Posted by: oikosasa | August 29, 2013

Editor’s Choice August

DriesLook up for the must-reads on the global biogeography of autotroph chemistry (Borer and colleagues) and litter decomposability of temperate rainforest trees (Jackson and colleagues). These are two different synthetizing contributions by reviewing the current state of the art and using an integrated, multispecies research approach.

Clearly, such contributions enhance our understanding of ecosystem functioning.

Posted by: oikosasa | August 20, 2013

Parasite changes during an epidemic

In the Early View paper “Rapid change in parasite infection traits over the course of an epidemic in a wild host–parasite population”, Stuart Auld and colleagues examines how parasite traits vary during an epidemic.

In this film, Stuart tells you more about the study:

and here’s more about Stuart’s research:


Posted by: chrislortie | August 15, 2013

Intecol 2013 presentations

Intecol meeting almost upon us! Remember, the Nordic Society is doing what I hope will be a very exciting session on biodiversity. This was a joint effort by Ecography & Oikos. I just completed preparing my talk.  Here it is as a little teaser!  I may also do a short video of it to practice.  Any other speakers game, post your talks too!


Posted by: oikosasa | August 14, 2013

Lessons from Late Jurassic

What can we learn from the Jurassic when it comes to modern Climate changes? read more in the Early View paper in Oikos Learning from the past: functional ecology of marine benthos during 8 million years of aperiodic hypoxia, lessons from the Late Jurassic by Bryony Caswell and Chris Frid.

Below is Bryony’s background story and summary:

“A few years ago whilst on a field trip Chris and I began discussing the ideas that form the basis for this paper.  To him Jurassic marine systems initially appeared to be very different from those we see today being dominated by exotic large marine reptiles, ammonites, belemnites and fish.  The seafloor however was more familiar in its composition of clams, snails, echinoids and so on.  Modern marine systems depend upon key functions delivered by sea-floor communities such as these.  The ecological functions support and regulate multiple processes in the marine ecosystem such as the regeneration of nutrients, absorption and treatment of wastes, and the provision of food. Our discussions led us to ask how will the functioning of marine systems respond to the rapidly expanding footprint of human pressures, such as climatic change and nutrient runoff, in the longer term? The effects that these pressures exert on the seafloor, and the wider marine system, are not unique to modern marine systems. The Mesozoic oceans suffered from similar, albeit natural, pressures the effects of which manifest as remarkably similar patterns of change.  This observation inspired us to explore the potential changes in the delivery of key ecological processes within the Late Jurassic oceans (~150 million years ago) as an analogue for the changes that we see today.

Our study is the first to quantify changes in ecological functioning of the ancient seafloor. The data we use comes from the Late Jurassic and covers ~8 million years of fluctuating regional ocean de-oxygenation, and with it we investigate changes in the biological attributes that supported the palaeoecological functioning in the Wessex Basin, Dorset, UK. The fossilised remains of the Late Jurassic seafloor contain gastropods, brachiopods, scaphopods, bryozoans, echinoids, serpulids, hydroids and crustaceans, but it was dominated by bivalve molluscs.

In the oceans today we are witnessing the rapid expansion of areas of low dissolved oxygen that is caused by a combination of warming and elevated nutrient/organic enrichment of the oceans. The Jurassic was a period of ‘greenhouse’ conditions and de-oxygenation was common in its shallow continental seas within restricted basins such as the Wessex Basin. The results of our analyses show that the species composition of the Late Jurassic seafloor communities changed in the face of the environmental stress caused by the decreased oxygen levels, but that ecological functioning was initially maintained – lowered oxygen levels did not trigger a switch to a seafloor ecosystem that worked in a fundamentally different way. However, as oxygen levels continued to decrease the system underwent a marked change in the way it functioned. We have been able to identify this threshold relative to geochemical proxies for environmental change.

The results of our study suggest that we may be able to identify the thresholds that will trigger this change in modern systems.  The modern seas and oceans support multiple ecosystem services and the collapse of ecological functioning has serious implications for coastal economies. Collapse of functioning is therefore a state that environmental managers should seek to avoid. The ecological changes we observe in the Jurassic are consistent with the patterns emerging from studies of modern systems. Functional collapse occurs rapidly once critical thresholds are exceeded and recovery from this often takes decades and follows a unique and unpredictable return path.


The cliffs near Kimmeridge showing clear metre scale alternation between organic-poor and organic-rich layers.  These variations reflect changes in oxygen levels at the seafloor during the Late Jurassic. 


Exploring the Jurassic seafloor as it is exposed, in the Kimmeridge Clay Formation, today on the foreshore.


A fossil rich bedding plane representing one of the hypoxic palaeocommunities (E2c).  It contains several of the dominant bivalve species (Protocardia morinica, Palaeonucula menkii, and Isocyprina spp.) and the limpet Pseudorhytidopilus latissima.”

Posted by: oikosasa | August 13, 2013

Meet our EiC in London next week!




Posted by: oikosasa | August 2, 2013

Moving plants and invasions

Climate change and plant movements and invasions was discussed during the ESA-meeting 2011. The result – a Forum paper is now published online in Oikos: “Movement, impacts and management of plant distributions in response to climate change: insights from invasions” by P. Caplat et al. Below you find Yvonne Buckley’s background story to the paper:

Plants are moving as their habitat changes due to climate change. If species are to persist they are required to adapt or move somewhere else. Species dynamics are extremely hard to predict, making global change research a challenging enterprise. Invasion ecology however has many case-studies, concepts and challenges in documenting, predicting and managing how species move, and how their movement affects ecosystems.

Invasive plants are extremely good at moving and present very real challenges for predicting where they will move to, how fast and how ecosystems will respond to immigrants. We invited 10 colleagues from around the world with diverse interests in the ecological, evolutionary and social dimensions of invasion to discuss how invasion ecology can contribute to predictions of plant movement in response to climate change at a special session of the 2011 Ecological Society of America meeting in Austin. Sparked by presentations and discussion at that session we wrote a discussion piece for the Oikos Forum.

Climate change and biological invasions exhibit similar dynamics and processes. In the following figure, we show A: a New-Zealand native tree (Nothofagus menziesii), recruiting above the climatic tree line in the Mataketake Range, New-Zealand (courtesy of M. Harsch); B: an invasive pine (Pinus nigra) expanding on a mountainous grassland near Lake Coleridge, New-Zealand.


In the paper, we outline the similarities between invasion dynamics and climate induced range-shifts. The figure below shows how concepts from invasion biology can contribute to questions relevant to climate change research.


Many of these concepts concern the properties plants should have to be able to track their environment or adapt to new conditions. The colonisation of new environments emphasizes the role of dispersal, which has been intensely studied in invasion biology. The following picture illustrates this. A: Invasive thistle Carduus nutans responded to experimental warming by growing taller, therefore increasing its dispersal ability; B: having light, winged seeds allows pine tree Pinus nigra to spread far and fast; C: the dispersal traits of invasive Crepis sancta evolved rapidly when the plants colonized a fragmented urban environment (courtesy of G. Przetak); D: high seed production , amongst other traits, allow Acacia pycnantha to invade grasslands in the Western Cape, South Africa.


Invasion processes are not entirely analogous with plant movements in response to climate change but they do present some useful examples and a large volume of data which could be synthesised to shed light on ecological, evolutionary and social processes that are involved when plants move.

Posted by: oikosasa | July 29, 2013

Swans go with the flow

Many animal species show seasonal switches in their habitat use. For example, animals may move between aquatic and terrestrial habitats, flowing and still waters, coastal areas and open seas, or forest floors and canopies. How do animals decide which habitat to use? One way to understand animal habitat selection is to focus on the energetic gains and costs associated with foraging in each habitat. This has been the basis of much ‘optimal foraging’ research over the past few decades. Foraging models, which calculate the net energy intake per unit time (‘profitability’) available to the animal while foraging in different habitats, can yield a process-based understanding of why animals switch habitats.

In our paper Go with the flow: water velocity regulates herbivore foraging decisions in river catchments , now published Eary View, we used a combination of observational, experimental and modelling work to understand why flocks of non-breeding mute swans (Cygnus olor) show a seasonal switch in habitat use in shallow river catchments. From our previous work, we knew that swans switch from feeding on grasses in pasture grass fields, to feeding on aquatic plants in the river itself, between April and May each year. Due to their high food requirement (up to 4 kg of fresh vegetation per day), lack of predators and high tolerance to disturbance, non-breeding swans are ideal for studies of the influence of foraging profitability on habitat selection. Hence we suspected that the habitat shift would be linked to seasonal changes in one or more of three parameters: food quantity, food quality, and metabolic foraging cost.


A flock of mute swans feeding on submerged plants in a shallow rive

A flock of mute swans feeding on submerged plants in a shallow rive


We combined field and literature data with an optimal foraging model to investigate the observed seasonal habitat shift by mute swans. Our study system for this investigation was the River Frome in southern England, which has a population of approximately 300 swans. We measured the quantity and quality of the two food resources available to swans, aquatic plants and pasture grass. We took quantitative plant samples each month from 18 paired river and field sites within the catchment to measure how the biomass of each food resource changed over the study period. The energy content of plant and swan faeces samples from four of these sites were determined using bomb calorimetry, which showed that the food quality was relatively constant over the study period. We estimated the intake rates for aquatic plants by conducting feeding experiments on captive swans, and for pasture grass by allometric scaling of published data. We used published literature and calculated water velocities to estimate foraging costs. Whilst foraging costs of pasture grass feeding were stable over time, river feeding became more efficient as water velocities declined between spring and summer; slower water meant less energy had to be expended swimming.


The lead author with a tray of swan faeces for energy analysis, illustrating the less glamorous side of working with large, charismatic vertebrates

The lead author with a tray of swan faeces for energy analysis, illustrating the less glamorous side of working with large, charismatic vertebrates


The lead author delivers part of the ad libitum supply of aquatic plants to a captive swan at the start of the functional response experiments

The lead author delivers part of the ad libitum supply of aquatic plants to a captive swan at the start of the functional response experiments


Finally, we used an optimal foraging model to predict the average net rate of energy gain in each habitat, for each month between March and September. The model could have either fixed values (i.e. average values for the study period) or variable values (i.e. monthly values) for the key parameters, to allow us to assess the effects of seasonal changes on profitability and habitat use. We compared the predicted ‘best’ habitat for each month with the observed field data on habitat use. By sequentially testing alternative models with fixed or variable values for food quantity, food quality and foraging cost, we found that we needed to include seasonal variance in foraging costs in the model to accurately predict the observed habitat switch date (i.e. April to May). However, we did not need to include seasonal variance in food quantity and food quality, as accurate predictions could be obtained with fixed values for these two parameters. Therefore, our model indicated that the seasonal decrease in aquatic foraging costs was the key factor influencing the decision to switch from pasture to river feeding habitats. Many previous studies have ignored the role of seasonal changes in foraging costs in driving switches between habitats. Our study offers a mechanistic understanding, based on the gains and costs associated with different food resources, of the observed shifts of a generalist herbivore between alternative habitats.

Understanding the factors which determine habitat selection are necessary to explain the patterns of animal distributions that we observe in nature. Furthermore, we aim to use our understanding of swan habitat selection to inform ecosystem management. Where they feed in shallow rivers, flocks of mute swans may damage the plant community and threaten conservation objectives. Herbivore damage to valuable plant communities is a problem seen around the world, for example deer in temperate woodlands and geese in agricultural crops. Where we understand the factors which determine herbivore habitat use, we may be able to manipulate these factors to shift herbivores away from the threatened habitat. Whether or not we can successfully use our understanding of the rules of habitat selection to devise practical habitat management schemes to prevent overgrazing, it certainly provides an interesting applied focus for future research in this area of ecology.

Kevin A. Wood

Posted by: oikosasa | July 26, 2013

Personality and metabolic rate

Do bold individuals have higher metabolic rates? Find out in the new Early View paper “Personality and basal metabolic rate in a wild bird population” by Sandra Bouwhuis and co-workers. Here’s Sandra’s short summary of the study:

Like humans, individuals of many species are found to vary in their personality type. Some individuals are bold and eager to explore new environments, while other individuals are shy and more cautious. Such personality variation has been suggested to be related to general lifestyle differences between individuals, such that bold individuals opt for a ‘live fast, die young ‘ lifestyle, while shy individuals invest in survival and the future. On the physiological level, such individual differences have been proposed to be supported by different metabolic machinery and, as a result, different metabolic rates. This latter theory was tested in a wild population of great tits, living in Wytham Woods in the UK, over three years. Contrary to the expectation, among 700 individual birds no strong relationship between metabolic rate and personality was found. Instead, the results of the study suggest that individual metabolic strategies may be highly variable and that such metabolic strategies, instead of an average metabolic rate, may be related to personality variation.

Wytham Woods mistnetted great tit personality assay room

Posted by: oikosasa | July 22, 2013

Mom knows best – maternal care in perennial plants

How can we provide the best circumstances for our kids? The new Oikos Early View paper “Adaptive transgenerational plasticity in the perennial Plantago lanceolata” , by Vit Latzel and co-workers, deals with this issue – in plants. Read Vit’s story here:

Imagine that you have to live your whole long life in one spot and that your kids, for whom you cannot even choose the father, will then live very close to you without the possibility of them finding a better environment. How can you best provide for them and make their lives at least slightly easier? This is exactly the challenge that many cross-pollinated long-lived plants must face. Luckily for some mothers, it seems that they can prepare offspring for the environment that they will be facing – giving them an advantage over unprepared competitors. They could do this through the mechanism known as adaptive maternal effects or adaptive transgenerational plasticity. However, rigorous demonstrations of this have been surprisingly rare, probably because appropriate experiments are difficult to conduct and/or the wrong traits have been measured. We did a straightforward experiment on the common perennial Plantago lanceolata (ribwort plantain), testing whether offspring grown in the same level of nutrient availability as their mothers were more successful than offspring grown in a non-maternal environment. Unlike other studies, we considered total carbon storage in roots as the measure of offspring success, because, in contrast to fitness estimates based on single-year fecundity, storage amounts accurately indicate long-term success of polycarpic perennials across several seasons. We found that offspring took an advantage of maternal environmental nutrient levels where they accumulated significantly more carbohydrates than those grown in non-maternal environments. This adaptive transgenerational plasticity was consistent across maternal genotypes and was not affected by climatic fluctuations during offspring development. Our work suggests that adaptive transgenerational plasticity is common in Plantago lanceolata. We also believe that if appropriate estimates of plants success are considered, similar transgenerational adaptive plasticity can likely be found in many other perennial species, and that transgenerational modification of storage dynamics in perennial plants can contribute to their ecological variation.

Ribwort plantain in a natural population and in our cultivation. Graph shows the higher level of carbon storage in offspring grown in maternal than in non-maternal nutrient environment.

Ribwort plantain in a natural population and in our cultivation. Graph shows the higher level of carbon storage in offspring grown in maternal than in non-maternal nutrient environment.

Posted by: oikosasa | July 19, 2013

Scared of darkness?

Are you scared of the dark? Predators can change the species present in a community by consuming particular individuals removing them from the ecosystem. However, a new paper published Early View in Oikos “Fear in the dark? Community-level effects of non-lethal predators change with light regime”, Coreen Forbes and Edd Hammill” shows that under dark conditions, fear of predation alone is enough to lose species from communities. Under dark conditions, photosynthesis is impossible meaning the only species that can survive are ones that can collect energy from existing sources. Moving around to collect this energy also increases the chances of encountering a predator, so when scared, some species reduce the rate at which they move around. This reduction in movement means other species can harvest the energy source faster than the “scared” species. Because the scared species is now less competitive, it can be driven to extinction despite the fact it is not being eaten by predators. Our research shows how important predators are for keeping ecological communities in order


Posted by: oikosasa | July 16, 2013

Welcome Isabel Smallegange – new SE

OLYMPUS DIGITAL CAMERAWelcome to the Oikos Editorial Board, Dr. Isabel Smallegange, University of Oxford, UK. Isabel’s research focuses on unravelling the mechanisms that maintain male polymorphisms, and on understanding and predicting the eco-evolutionary consequences of (human induced) environmental change. In her studies she uses mites as a model system and combines modelling with behavioural and population experiments. More info is found on her website:‎.

Isabel, what’s you main research focus at the moment? 
The focus of my research is to understand how ecology and evolution interact to determine the evolution of traits and the dynamics of populations in response to environmental change. I specifically focus on the evolution of male dimorphism and combine theory with experiments to unravel the links between ecology and evolution.

Can you describe you research career? 
I started out in behavioural ecology as I was (and still am) fascinated by all the different behaviours that animals display. During my PhD at the Netherlands Institute for Sea Research I studied the foraging behaviour of shore crabs. However, by the end of my PhD I wanted to scale up my work to the population level, which was not possible with shore crabs, and therefore I went to the Max Planck Institute for Ornithology to analyse long-term datasets on bird abundances. This first Post Doc was a great learning experience, however, I missed the experimental element to my research and moved to Imperial College London where I set up a laboratory to use mites as a model system to study population dynamics and the evolution of male dimorphism. My lab has now moved to the University of Oxford where I’m continuing my research on eco-evolutionary dynamics.

male morphs mites more mites copy

How come that you became a scientist in ecology? 
I always liked biology and from a young age I was fascinated with animal behaviour. I actually thought I would never be able to get a job in behavioural ecology but, luckily, I did find a PhD position to study animal behaviour. During my PhD I learnt many different skills that set me up for a career in ecology. Although now I’m not studying animal behaviour anymore, I still work with animals on very exciting questions in ecology and evolution.

What do you do when you’re not working? 
At the moment I spend most of my spare time with my 6-month old son who demands a lot of attention!

Selected publication: Smallegange IM, Coulson T. 2013. Towards a general, population-level understanding of eco-evolutionary change. Trends in Ecology and Evolution 28:143-148.

The introduction of non-native plants usually invokes a wave of pessimism among biologists.  Some of these introduced plants can invade natural ecosystems where they can cause tremendous problems.  And to make matters worse, it is very difficult to predict much about the ecological impact of a particular non-native plant prior to its introduction.  We argue that one important consequence of a plant introduction is fairly predictable:  which native herbivores are able to colonize it.

In the Early View Oikos paper “Predicting novel herbivore-plant interactions”, Ian Pearse, David Harris, Richard Karban, and Andrew Sih argue that we can predict which native herbivores will successfully colonize which introduced plants if we understand some of the mechanisms of native herbivore plant interactions and the general properties of native food webs.

The basis for predicting novel associations between herbivores and plants is to define the “match” between an herbivore and its potential hosts.  The logic behind this ends up being analogous to the way the Netflix movie website guessed (perhaps correctly) that I might like to watch “His Girl Friday” next (it is similar to another movie that I watched recently) or maybe an episode of “Downton Abbey” (a show that seems to be popular with many people right now).  Indeed, the attempts to “match” us with a novel product (log in to Amazon) or person (visit are essentially pervasive to anyone who ventures onto the internet.  This works because internet sites and companies collect a large (creepy?) amount of information about us and the products they sell.

Microsoft PowerPoint - hostmatchdotcom.ppt

In the context of novel herbivore-plant associations, we already know many of the factors that drive these associations (phylogenetic constraint in host breadth, secondary metabolites, phenology, etc).  And we have even begun to compile information about many native plant-herbivore food webs, which is perhaps akin to Netflix’s list of movies that I and other costumers have watched.  So, this paper suggests that (when armed with accurate native food webs and good lists of plant traits and evolutionary histories) we can start to make more accurate predictions about which native herbivores will colonize which non-native plants.

Of course, the natural history of individual organisms is complicated, and some interactions will be hard to predict.  For example, the interaction between an herbivore and its novel host is an evolving relationship (see a recent Oikos review by Matt Forister dealing with this topic).  But for many cases, herbivore interactions may be one of the most predictable elements of plant introductions.

Posted by: oikosasa | July 9, 2013

Editor’s Choice July

The Editor’s choice papers in the July issue of Oikos are “A critical analysis of the ubiquity of linear local–regional richness relationships” by Goncalves-Souza et al. and “Bottom–up and top–down forces structuring consumer communities in an experimental grassland” by Rzanny et al.  Both are available free online! Here’s the EiC’s motivation for the choice:

DriesBesides promoting synthesis, Oikos has a tradition in publishing studies that challenge widely accepted ecological paradigms. The ubiquity of linear relationship between local and regional species richness is such an idea that found its way to many textbooks. The potential impact of regional and local processes on community structure has been traditionally tested by regressing local against regional species richness. This approach was justified by the idea that communities controlled by regional processes are unsaturated, while those affected by local processes are not. However, while such a linear relationship has been theoretically criticized, a critical reevaluation has so far not been done. Thiago Gonçalves-Souza and colleagues reanalysed published studies with a new unbiased method and found no prevalence of linear relationships and more than 40% of misclassifications. Its apparent ubiquity appeared to be due to the use of biased statistical methods (linear regressions to detect linearity). The study demonstrated such local-regional diversity relationships to follow other ‘rules’ than linear ones. The metacommunity perspective provides a framework to study the importance of processes acting and interacting at different spatial scales. A full understanding of these mechanisms will ultimately generate synthesis on the form and strength of the local-regional diversity scaling rules.

While this framework likely advances our understanding of the processes leading to species diversity, we still lack proper insights on the relative strength of different local mechanisms (food web interactions for instance) that structure species communities. Species at intermediate trophic levels (consumers) are expected to be affected by the interplay between bottom-up and top-down effects, but synthesis on the relative importance of these effects is lacking. By analysing data from a long-term grassland diversity experiment, Michael Rzanny and colleagues demonstrate bottom–up forces to account for the major part of the explainable variation within the composition of all functional groups of consumers (plant chewers, suckers , saprophages) but also predators and parasitoids. Legumes appeared to be an especially important driver of consumer community structure. Predator-mediated top–down forces also influenced the majority of consumer functional groups, but were much weaker. In order to partition the different sources of variation, redundancy analysis was applied. Equally interesting, and again emphasising the interactive effects between local and regional processes, was the importance of different spatial components for explaining, especially, predator community structure.

The Nordic Society has put together a special symposium for the upcoming Intecol meeting.  We hope to see you all there and that you will find it an interesting set of talks.  It is a double session on Tuesday August 20th in the morning. The full programme details will be available by the end of July apparently.

Goals of the diversity symposium

The primary objective of this symposium to highlight the breadth of diversity studies, both empirical and theoretical, with an eye to promoting novelty and identifying research gaps for the next 100 years.  Ancillary goals that will be addressed to meet this overarching objective include the following.

(i) To critically examine scale as it relates to understanding ecological and evolutionary processes that shape patterns of diversity.

(ii) To develop a clear set of directions for future studies of diversity that augment species diversity estimates with genetics in spatial landscapes.

(iii) To describe pivotal concepts and relationships that limit our capacity to effectively use and measure diversity and how it has changed and will change in the future and propose solutions.

(iv) To identify the critical species and places that anchor diversity studies and enhance diversity in changing climate.

The line-up of speakers is very extensive, and the second column in each table lists the allotted time.  We designed the first session to cover mover ground quickly and directly and the second session provides a bit more time for their respective topics.

Session 1 chaired by Jens-Christian Svenning

Dr Richard Michalet The contribution of local-scale facilitative interactions to community diversity and composition


Dr Carlos Melian Connecting diversification and biodiversity dynamics across spatial scales


Mr Tadashi Fukami Spatial scale and the historical contingency in community assembly as a source of beta diversity


Dr Brody Sandel Patterns of diversity across scales: Challenges and opportunities


Dr Hanna Tuomisto A critical look at the diversity of diversity: do we know what we are talking about?


Dr Pedro Peres-Neto Spatial autocorrelation, metacommunities, and null models: the thrills of diversity


Dr Franz Uiblein Widely distributed species versus species complexes in the oceans: where to go towards management of species-rich resources and habitats?


Summary by Chair


Session 2 chaired Christopher Lortie 

Dr W. Daniel Kissling Multi-species interactions across trophic levels at macroscales: retrospective and future directions


Mr Matthias Schleuning Integrating functional and interaction diversity into biodiversity-ecosystem function research


Dr Lonnie Aarssen Evolution and the sizes and numbers of species:  unpacking the diversity of vegetation


Dr Christian Schöb Global patterns of β-diversity along alpine gradients point to locally changing drivers of community assembly – but only in the absence of foundation species


Dr Christopher Lortie Diversity versus interactions: are diverse groups more important than large effects?



Posted by: chrislortie | July 3, 2013

Fun ecological synthesis facts

In my recent explorations into synthesis and the role of Oikos and other major drivers of this movement, here are some facts from Web of Knowledge and online search tools.

(1) Close to 20,000 primary research publications discuss/report effect size estimates in ecology.

(2) Approximately 15 times more meta-analyses published in ecological journals relative to systematic reviews.

(3) PLOSONE publishes majority of systematic reviews for most disciplines possibly including evolutionary biology.

(4) Historical signal of narrative reviews persists in modern synthesis.

(5) Citations per item to meta-analyses now trump narrative reviews.

(6) Oikos ranks 5th in publishing meta-analyses.

(7) The benefit to effort for systematic reviews generally higher than meta-analyses*.

*However, see pre-print on this as it does not necessarily mean we should do them instead of meta-analyses as evidence-based transformations are more likely to occur from meta-analyses.

frequency finalcites final

oikos meta-performancebenefit-effort plot

Posted by: chrislortie | July 3, 2013

Synthesis in ecology

I am experimenting with PeerJ as a new model to get friendly peer-review in advance of submitting to a journal.  Two papers were on my plate – a general synthesis and role of meta-analyses and systematic reviews paper and a more practical paper on how to interpret them. Any feedback appreciated!

Formalized synthesis opportunities for ecology: systematic reviews and meta-analyses. 

Practical interpretation of ecological meta-analyses.

synthesis solar system.003

Posted by: oikosasa | July 3, 2013

How does increased temperature affect herbivory?

Now online: “Increased temperature alters feeding behavior of a generalist herbivore” by Nathan P. Lemoine and co-workers. Read more about how an  increased temperature may affect plant growth and herbivory:

Temperature plays a crucial role in determining ecological processes. For example, temperature can control rates of predation, herbivory, individual growth rates, population growth rates, and mortality rates, to name a few. Unfortunately, we know little regarding the effects of temperature on herbivore choices. That is, we do not fully understand how temperature influences which foods herbivores choose to eat or which foods provide optimal diets. Herbivore physiology is strongly controlled by environmental temperature (if the herbivore is an ectotherm), as rising temperatures promote growth (to a point) and increase the demand for vital nutrients, like sugars, proteins, nitrogen, or phosphorus. If true, then daily, seasonal, decadal, or climatic fluctuations in temperature should alter the plants that herbivores consume.

We tested the hypothesis that temperature alters herbivore performance (consumption and growth rates) and feeding preferences among plant species using the Japanese beetle, Popillia japonica.


We found that the effects of temperature on P. japonica growth and consumption rates varied widely among plants species: increased temperatures stimulated growth on some plants and decreased growth on others. The differences in growth among plant species are attributable to plant nutritional quality. At low temperatures, plant nutritional content did not affect beetle growth. At high temperatures, beetles grew best on plants with high nitrogen and carbon content, perhaps reflecting increased demand for nitrogen-rich materials or carbohydrates.

Additionally, by extracting plant secondary chemicals, we found that temperature reorganizes beetle feeding preferences by altering the effects of plant chemical defenses. Interestingly, the plants that beetles preferred at high temperatures were not the plants on which beetles grew best, indicating that the beetles were making decisions that may not lead to optimal growth rates.


Our results indicate that direct effects of temperature on herbivore physiology can possibly re-organize the intensity of herbivory among plant species and that these changes can be predicted based on plant nutritional quality. These changes will become more important in the future as the climate warms.

Posted by: oikosasa | June 28, 2013

Exploitation-interference link

How interference competition affect population dynamics is explored in the new Early View paper in Oikos “Linked exploitation and interference competition drives the variable behavior of a classic predator–prey system” by John P. DeLong and David Vasseur. Here’s John’s background story and summary:

We had a hunch. While trying to understand how interference competition works, we began to suspect that traits that influenced the rate at which consumers encountered their resources would also influence the rate at which consumers encountered each other. Maybe some measure of exploitation competition would therefore be related to a measure of interference competition.

Figure 1. Traits that influence the rate of consumer-resource encounters might also influence the rate of consumer-consumer encounters, generating a link between exploitation and interference competition.

Figure 1. Traits that influence the rate of consumer-resource encounters might also influence the rate of consumer-consumer encounters, generating a link between exploitation and interference competition.


To find out, we measured foraging rates in the classic Didinium nasutum – Paramecium aurelia predator-prey system. By measuring foraging rates at different levels of both the predator and the prey, we could fit a functional response to the data and retrieve estimates of parameters that reflect the magnitude of these forms of competition. If there was any variation in those parameters, we would expect it to be correlated.


Figure 2. Here a Didinium nasutum is consuming a Paramecium bursaria.

We created 16 different populations and nudged them in different directions – they received varying amounts of nutrients, varying amounts of prey and predators, and were allowed to grow for different amounts of time. Then we pulled individuals from the populations and conducted the foraging experiments, once for each population separately. Our functional response included the power-law form of interference – mutual interference – and the standard ‘a’ parameter that characterizes exploitation. Across the populations, exploitation was strongly correlated with interference.

Figure 3. Interference competition (which gets more intense as it gets more negative) is strongly and positively related to exploitation competition (a).

Figure 3. Interference competition (which gets more intense as it gets more negative) is strongly and positively related to exploitation competition (a).


Turns out we weren’t the first ones to suspect this. In 1954, Park suggested that the two forms of competition might be linked, but since that time research into competition has largely investigated interference separately from exploitation. Keeping them separate is likely to obscure how competition influences ecological and evolutionary dynamics, especially given that interference can have a rather strong impact on foraging rates.

For example, the Didinium – Paramecium is famous for having highly variable dynamics. Usually, dropping a few Didinium into a plate full of Paramecium leads to one cycle of growth followed rapidly by the extinction of both populations. However, slowing everything down can lead to more oscillatory behavior. These variable dynamics are easily explained by the link between exploitation and interference, with low interference and low exploitation leading to oscillatory dynamics, intermediate competition values leading to stabilized dynamics, and higher values of both leading to deterministic extinction.

Figure 4. Predator-prey dynamics, here simulated for Didinium – Paramecium, vary from oscillatory to deterministic extinction due to the correlated nature of the interference and exploitation parameters.

Figure 4. Predator-prey dynamics, here simulated for Didinium – Paramecium, vary from oscillatory to deterministic extinction due to the correlated nature of the interference and exploitation parameters.


We also found a way to modify the mathematical formulation for the ‘a’ parameter that generates the kind of exploitation-interference relationship we observed. This model suggests that the rate of travel of the predator is an important driver of both forms of competition, bringing a measurable trait to bear on this problem.

Posted by: oikosasa | June 25, 2013

Welcome Michael Scherer-Lorenzen – new SE!

Michael Scherer-Lorenzen has just joined the Editorial Board of Oikos. Get to know him by reading the presentation below. And welcome to Oikos, Michael!

Scherer-Lorenzen_webIn my research I aim to mechanistically understand the biotic control of ecological processes and how global change drivers – such as climate change, land use change, nitrogen deposition, or invasive species – are interacting with this control.  Within this field I focus on the functional role of biodiversity for productivity and biogeochemical cycles. I am currently coordinating the EU Framework Programme VII project FunDivEUROPE, which aims to quantify the role of forest biodiversity for ecosystem functioning and the delivery of goods and services in major European forest types.


1. What’s you main research focus at the moment? 

Does it matter to the way how ecosystems function whether there are only few or many species present? And if so, which are the mechanisms behind such biodiversity effects on ecosystem processes? Do such functional effects of biodiversity change with changing land use intensity or climate?
These kind of questions are at the basis of my group´s current field of research. We are focusing on processes such as productivity or nutrient cycling, with litter decomposition and plant nutrient uptake being key functions. One challenge we are currently dealing with is the quantification of resource use complementarity, which is one main mechanism that could explain positive plant diversity effects on productivity. In terms of study systems, we work in grasslands and forest ecosystems mainly, using both experimental and comparative appraoches.


2. Can you describe you research career? Where, what, when? 

Because there was a strong focus on ecology at the University of Bayreuth, Germany, I went to this little city in northern Bavaria in autumn 1988, to study Biology. I finished my studies with a thesis on land use effects on plant communities in Southern Chile.
In 1995, I begun my PhD within the pan-European BIODEPTH project under the supervision of Detlef Schulze. BIODEPTH was the first biodiversity – ecosystem functioning experiment in Europe at that time and was coordinated by John Lawton. The whole consortium was a real dream-team, and I learned a lot.
After finishing the PhD in 1999, I worked as an assistant to Detlef Schulze in the German Advisory Council on Global Change (“WBGU”), followed by a position as Executive Director of the Institute of Biodiversity Network (ibn). These two jobs offered interesting insights into policy advising and the function of important international treaties, such as the UN Convention on Biological Diversity, CBD.
I went back to science in 2001 as a research scientist at the Max-Planck-Institute for Biogeochemistry in Jena, Germany, where I established a large tree diversity experiment (BIOTREE).
From 2003 to 2009 I was working in the research group of Nina Buchmann at ETH Zurich, Switzerland. Here, I started to use isotopic tracers to quantify resource use complementarity and to study drought effects on alpine grasslands.
Finally, in April 2009, I got the position as a Professor for Geobotany at the University of Freiburg, which enabled me to set up my own research group on functional biodiversity research.OLYMPUS DIGITAL CAMERA

3. How come that you became a scientist in ecology? 

It all begun during field trips with my parents (my father collected beetles), where my fascination for nature was born. In school, I participated in nature conservation actions and research competitions. For example, together with friends, I was mapping amphibians or developped a protection programme for social wasps. So, it was very clear for me that I wanted to study biology after school. And so I went to Bayreuth…see above.


4. What do you do when you’re not working? 

We have two wonderful children, Falk and Alva, who take most of my non-working time, of course. We are often going out into the forest just behind our garden, or take the bicycle, or play football.

Selected publication:
Scherer-Lorenzen, M. (2013). The functional role of biodiversity in the context of global change. In: D. Burslem, D. Coomes, & W. Simonson (Eds.), Forests and Global Change. Cambridge: Cambridge University Press. In press.

Posted by: oikosasa | June 18, 2013

Fish eye view of forest canopies

 “In discussing the peculiar type of refraction which occurs when light from the sky enters the surface of still water, it seems of interest to ascertain how the external world appears to the fish.” With these words renowned physicist R.W. Wood, Professor of Experimental Physics at Johns Hopkins University and proud owner of one of the firsthome aquariums, started his 1906 article “Fish-Eye Views and Vision Underwater“. The article was set to offer a scientifically based description of how a fish might view the world outside his glass tank.

Fish eye 1Even with all his intellectual curiosity and intuitiveness, Prof. Wood probably could not have imagined that decades later a modern descendant of the water camera he had once designed would be balanced on tripods in forests around the world. Nor could he have envisioned that it would soon become the standard field instrument for characterization of canopy structure and light regimes of forest ecosystems.

But let’s take a step back to understand how the fish got to view the forest.

The phenomenon Prof. Wood exploited in his experiment is governed by Snell’s law. Dating back to the 17th century, Snell’s law also known as Snell’s window is a phenomenon by which an observer looking up from beneath the water sees a perfectly circular image of the entire above-water hemisphere—from horizon to horizon. This is caused by refraction, light bending as it travels from one medium (air) to another (water). As argued by Prof. Wood, the cone of light entering the fish’s eye has an aperture of about 96°, but the rays within it came originally from a cone of 180°. This is the same phenomenon by which a fisheye lens (or hemispherical lens) is able to reach far to the sides of a scene and pull in the visual information of the entire hemisphere onto a plane.

The first practicable methods of hemispherical photographs were developed in 1924 shortly after Dr. R. Hill developed the first fisheye camera for cloud survey records and formation studies. During mid the 50s two ecologists, G.C. Evans and D.E. Coombe from the Botany School of the University of Cambridge, learned that one of these ingenious fisheye cameras had survived the war. Shortly after, they were standing under the dense shade of a small tree of Napoleona vogelii situated in Oil Palm bush near Ibadan, Nigeria. Of course – taking hemispherical photographs.

In 2007 another camera equipped with a fisheye lens was pointing upward to the sky in the canopy of yet another tropical forest, this time in Taita Hills South-East Kenya, where Alemu Gonsamo and colleagues from the University of Helsinki were conducting an extensive measurement campaign for the remnant cloud forest fragments.  Gonsamo and colleagues did not have to face many of the technological shortcomings Evans and Coombe were confronted with just half a century earlier. At that time hemispherical photograph analysis required tedious manual overlaying of sky quadrants and superimposing the track of the sun. With the advent of personal computers and with the replacement of film cameras by digital cameras, researchers are now able to develop digital analysis techniques (link here) and today various commercial and non-commercial software programs have become available for rapid hemispherical photograph processing and analysis. Yet many fundamental issues remain to be resolved.

The resulting hemispherical photographs serve as a permanent record of the canopy geometry, which can be precisely used to characterize canopy structure and light regimes. Canopy structural parameters are critical to adequately represent vegetated ecosystems for purposes ranging from primary productivity, climate change studies, water and carbon exchanges, and radiation extinction. However, as observed by Gonsamo and co-authors, standardization in the definitions of the fractional canopy cover and openness parameters has fallen short, leading to confusion of terms and concepts even in standard text books, making the comparison of historic measures futile.

Fish eye2

In the Oikos Early View paper Measuring fractional forest canopy element cover and openness–definitions and methodologies revisited Alemu Gonsamo and colleagues take an exciting tour, reviewing concepts, polishing up definitions, and presenting new methodologies to obtain large scale fractional canopy element cover and openness measures using photographs with a fisheye view perspective. Finally, in their Oikos paper, Gonsamo and colleagues argue that hemispherical photography is less time, labour and resource intensive, as compared to the traditional point based measuring techniques of canopy element cover and openness. This included measurements in topographically complex terrains.

Posted by: oikosasa | June 14, 2013

Editor’s Choice June


Oikos’ Editor-in-Chief, Prof. Dries Bonte, explains his choice of EC-papers for the June issue:

Editor’s choice papers from the June issue create synthesis on invasions.

Zenni & Nuñez  focus in a forum paper “The elephant in the room: the role of failed invasions in understanding invasion biology” on the importance of failed invasions to understand mechanisms behind invasions. They provide a review on studies documenting success and especially failures of invasions and found –not surprisingly I have to say- that only few studies have documented conclusively why populations fail to invade. The authors followed a paired approach contrasting environmental factors in invasive versus non-invasive populations of different species. They were, despite the lack of a well-developed research framework, able to demonstrate that different mechanisms may be causing failures vs. successes: propagule pressure, abiotic resistance, biotic resistance, genetic constraints and mutualist release. Rafael and Martin discuss the evidence available for the factors associated with these failures to invade. They additionally identify research field that are likely to produce misleading insights when neglecting these mechanisms of failure. Such biased reporting may thus not only mislead researchers, but certainly managers on the mechanisms leading to invasions.

There is consensus that when introduced organisms invade, they may cause considerable changes in community and ecosystem dynamics. While invasions are generally associated with negative impacts, Paul Gribben and colleagues demonstrate in their paper “Positive versus negative effects of an invasive ecosystem engineer on different components of a marine ecosystem” that an invasive engineer species may also contribute positively to marine community structure. They more specifically studied the impact of the invasive green alga Caulerpa taxifolia in southeastern Australia on the composition and abundance of the epifaunal and infauna community. More detailed species responses where experimentally approached. While contrasting impacts on different community components were obvious, they also showed that community change following the invasive species’ removal appeared strongly density dependent with the degree of recovery five months post removal related to the initial biomass. Areas with different biomasses of habitat-forming (invasive) species may subsequently have different temporal recovery trajectories. So, as highlighted by Zenni & Nuñez, the impact of the invasive species is strongly context-dependent and its impact differs according to the community components under study.

Posted by: oikosasa | June 12, 2013

Welcome Anna-Liisa Laine – new SE

We’re very happy to welcome Anna-Liisa Laine, University of Helsinki, Finland, to our Editorial Board!

Anna-LiisaRead more about her below and visit her website

What’s you main research focus at the moment?
Much of my research is focused on understanding why pathogens occur where they do. To get at this seemingly simple question I combine
experimental and molecular studies of host-pathogen co-evolution with data on epidemiology. I’m especially interested in how variation is generated in host resistance and pathogen infectivity, and how this variation affects epidemiological dynamics. While I mainly study within season disease transmission, I’m also extremely interested in how parasites transmit from one season to the next.
At heart I’m an ecologist and we do our field work in the Åland archipelago where 4000 meadows are annually surveyed for fungal pathogens of plants.

Can you describe you research career?
After completing my Masters at the University of Oulu in 2001, I started a PhD in the Metapopulation Research group at the University of
Helsinki, under the supervision of Ilkka Hanski. In my PhD I focused on understanding how host-parasite coevolution proceeds in a situation where the hostpopulations are highly fragmented. I defended my theses in 2005 and in 2006-07 in did a post doctoral project in the lab of John Thompson at the University of California, Santa Cruz. There we focused on understanding how plant-pollinator mutualism responds to changes in the local Community composition. I had another post doctoral stint in 2009-10 in with Pete Thrall and Jeremy Burdon at CSIRO, Canberra, Australia. There I had the opportunity to work with the classic wild flax-rust pathogen interaction,
addressing questions of host-parasite coevolution. Now I’m back at the University of Helsinki where I started my own lab in in 2010, and I
work as an Academy research fellow.

How come that you became a scientist in ecology?
When I was a high school student, I loved cell biology, and coming from a family of scientist going into seemed like an obvious choice.  However, when I started my studies at the university, I became fascinated with ecology. This was mainly due to two professors in those early years, Lauri Oksanen and Juha Tuomi. I had the chance to work as a research assistant in Lauri’s herbivory project and my interest for species interactions has continued ever since.

What do you do when you’re not working?
With two small kids, I’ve spent a fair amount of time playing with legos and finger painting recently… When I have a chance, I go

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Posted by: oikosasa | June 4, 2013

How ants and plants interact over space in the Amazon?

I protect you and you feed me, says the ant to the plant…read more about ecological networks in the new Early View paper “Spatial structure of ant–plant mutualistic networks” by Wesley Dattilo and coworkers.

In tropical environments, ant diversity is extremely high, reaching approximately 500 species at local scales. Because of both their abundance and diversity, it is extremely common to see ants foraging on plants. Within a spatial environment with a remarkable diversity (eg. Amazon rainforest) different plant and ant species can interact with each other and generate complex ecological networks of interactions. In this study, we studied how ants and plants with extrafloral nectaries interact over space, and we show that although the ant and plant composition of networks changed over space, the highly connected plants and ant species, and the structure of networks remained unaltered on a geographic distance of up to 5,099 m in the southern Brazilian Amazon. These finding indicate that different populations of plants and ants can interact in the same way independently of variation in local and landscape environmental factors. Therefore, our study contributes to understanding of the maintenance of biodiversity and coevolutionary processes in ecological networks.

Ants collecting extrafloral nectar on a plant in the fieldwork.

Ants collecting extrafloral nectar on a plant in the fieldwork.

Wesley Dáttilo collecting ant-plant interactions in the southern Brazilian Amazon

Wesley Dáttilo collecting ant-plant interactions in the southern Brazilian Amazon

Posted by: oikosasa | May 31, 2013

Welcome Sa Xiao, new Oikos Editor!

We also welcome Dr. Sa Xiao, Associate Professor at School of Life Sciences, Lanzhou University China. Learn more about him below and on his website

Sa Xiao1

What’s you main research focus at the moment?

My research interests mainly focus on the theoretical ecology and plant ecology. I am particularly interested in the areas of competition and facilitation, species coexistence and diversity, community structure and function. I use computer simulation model as the main research tool, especially the individual-based model programmed with multi-agent modeling language Netlogo. My current researches investigate the relative contributions of neutral theory’s process and niche theory’s process in explaining the multiple empirical patterns at the community-level, such as diversity-productivity relationship.

Can you describe you research career?

I took my PhD at School of Life Science here at Lanzhou University in 2006, where I have been Assistant and Associate Professor since then. In 2009-2011, I did a post-doc in Richard Malet’s lab nin Bordeaux, France. And I have been a Visiting Professor  in Ragan Callaway’s at University of Montana lab during 2010.

 How come that you became a scientist in ecology?

When I was in high school, I had a naïve belief that “Darwin’s theory solved the problems of living nature, and Marx’s theory solved the problems of human society, whereas how to solve the problems between human and nature? This should be the responsibility of ecologist”. So I decided to choose ecology as my life-time career.

 What do you do when you’re not working?

I like cooking very much and I’m particularly well versed in cooking Chinese food. I have strong interest in traditional Chinese philosophy such as Confucianism, Taoism, Yi- ology and Zen. I also like pop music, table tennis and swimming.

And a selected paper:

Xiao, S., Callaway, R.M., Newcombe, G. and Aschehoug E.T. (2012) Models of experimental competitive intensities predict home and away differences in invasive impact and the effects of an endophytic mutualist. The American Naturalist 180, 707-718.

Posted by: oikosasa | May 28, 2013

Welcome Mei Sun, new Oikos Editor!

We’re very happy to welcome Dr. Mei Sun, School of Biological Sciences, University of Hongkong to our editorial team!
Get to know Mei Sun here:
What is your research interest?
My main research focus at the moment is on plant speciation mechanisms and biological or other features that facilitate the rate of evolutionary diversification of angiosperms, especially in the family Orchidaceae as well as the Rhizophoraceae.
Can you describe your research career?
I became interested in plant ecology when I was an undergraduate working on a final-year thesis project in the field. During my postgraduate studies at the University of British Columbia, I become more interested in plant evolutionary biology. My Ph.D. research was on evolutionary genetics of Hawaii endemic species of Bidens (Asteraceae), a morphologically and ecologically diverse group arising from a single long-distance dispersal event followed by adaptive radiation into a variety of habitats on the Hawaiian Islands.
What made you become a scientist in ecology?
I am a molecular ecologist in the broad sense. Using various molecular marker systems, We aim to address various evolutionary questions, such as the investigations of genetic structure and outcrossing rates of hermaphrodites in natural populations of Bidens to determine whether inbreeding depression is one of the major factors in the evolution and maintenance of gynodioecy (e.g., Sun & Ganders 1986 Evolution); genetic diversity and evolutionary origin of Spiranthes orchids in Hong Kong (e.g., Sun 1996,1997 American Journal of Botany; Sun 1996 Conservation Biology); genetic resources and crop evolution (e.g., Amaranthus, sweetpotato, and rice); natural hybridization and phylogeography of Rhizophoraceae. More recently, I am also interested in comparative genetic analysis to understand the evolution of invasiveness in plants that are exchanged between SE Asia and Americas.
What do you do when you’re not working?
Reading about any subject that catches my attention at the moment; listening to soundscape music; watching TV; and doing Yoga …
For a recent representative publication:  please see
Mei Sun, Eugenia Y. Y. Lo   2011
Research Article | published 11 May 2011 | PLOS ONE 10.1371/journal.pone.0019671
Posted by: oikosasa | May 24, 2013

Can native species be invasive?

What should be included in the term “Invasive species”? In the new Early View Forum paper “Another call for the end of invasion biology”, Loic Valery discusses the issue. Here is a short summary of the paper:

The bulk of the literature devoted to biological invasions ignores native species and restricts the field of study to only introduced species. This split used by many researchers to justify the emergence of a distinct discipline is increasingly openly challenged.

Based on the etymology of the word “phenomenon” (i.e. what is seen, what is perceived by the senses), we show that a biological invasion manifests itself, always and only, by the rapid appearance of a state of dominance of a species. Therefore, there is no reason to take into consideration other factors (in particular, the biogeographical origin of the invader) that prove to be both inappropriate and inoperative from a theoretical and practical viewpoint, respectively.

Thereby removing any justification for the autonomy of invasion biology, we advocate a more integrated study of all species on the move.

Sus scrofa_A. MauxionElymus athericus_A. Mauxion

Invasive species can also be native. Here are two examples of native invaders in Europe:  the sea couch grass Elymus athericus Link spreads in salt marshes, from high marsh towards middle and low parts where it forms large dense monospecific stands (here, in the Mont-Saint-Michel bay); and  the wild boar Sus scrofa L., whose populations have exploded demographically in forests and agricultural systems, now extends in big cities such as Berlin, Milan or Barcelona for foraging. (Photographs: courtesy of André Mauxion).

Posted by: oikosasa | May 21, 2013

Even the small ones are important!

Size is not all! Even small herbivores have effect on plant community, as shown in Salvador Rebollo and co-workers new Early View paper shows: “Disproportionate effects of non-colonial small herbivores on structure and diversity of grassland dominated by large herbivores”.

Here is a summary of the study by Rebollo:

Daniel G. Milchunas and Salvador Rebollo, two out of five authors of the article, along-side a large-plus-small herbivore exclosure in the shortgrass steppe.  We tested our hypotheses over a 14-year period in pastures grazed at moderate intensities by cattle and in two types of exclosures: for large (barbed-wire) and for large-plus-small herbivores (small-mesh hardware cloth).

Grasslands are grazed by a complex assemblage of herbivores that differ in body size, abundance, diet, and foraging strategies.  Grazing studies have most often examined effects of large herbivores, probably due to their greater amounts of plant consumption and economic importance.  Studies of small herbivores have focused on social, central-place foragers that reach high local densities and build conspicuous burrow systems, such as prairie dogs or European rabbits.  The role of more evenly dispersed small herbivores in structuring vegetation, especially in perennial grasslands, has been less studied.  What is the importance of these cryptic small herbivores?

Our research was conducted in the semiarid shortgrass steppe of the North American Great Plains, a grassland with a long evolutionary history of grazing by large generalist herbivores and one of the most tolerant ecosystems to grazing by these herbivores.  This ecosystem is considered marginal habitat for small herbivores (except for the social and colonial prairie dogs) due to the lack of overhead cover, the low seed-to-vegetation production ratios, and small seeds of the dominant plant species.  Peak biomass and consumption of rodents and rabbits was estimated to be a fraction (<8%) of that of large herbivores.  We hypothesized that 1) large generalist herbivores would affect more abundant plant species and proportions of litter (old fallen vegetation), bare ground, and vegetation cover through non-selective herbivory, and 2) small herbivores would affect cover and richness of less abundant species, through selective but limited consumption.

Photo 2

Vegetation in one of the large-plus-small herbivore exclosures. Exclusion of herbivores of both body sizes had complementary and additive effects that were linked to increased abundance of tall and decreased abundance of short plant species. Uncommon species as a group were not affected by the additional exclusion of small herbivores, but the tall annual Tragopodium dubious (compositae plant located in the front part of the photo), was an example of one uncommon species that did increase with small herbivore exclusion.

David Augustine conducts a prescribed burn in shortgrass steppe at the Central Plains Experimental Range.

David Augustine conducts a prescribed burn in shortgrass steppe at the Central Plains Experimental Range.

The study site was at the Central Plains Experimental Range (CPER) in northeastern Colorado, USA, one of the Long Term Ecological Research (LTER) grassland sites (Photos 1 and 2), as well as a Long-Term Agro-ecosystem Research (LTAR) network site.  We found that the exclusion of large herbivores affected litter and bare ground, and basal cover of abundant, common, and uncommon species.  Contrary to our hypothesis, additional exclusion of small herbivores did not affect uncommon components of the plant community, but had indirect effects on abundant species, decreased the cover of the dominant grass Bouteloua gracilis (blue grama) and total vegetation, and increased litter and species diversity.

Paul Stapp handles a thirteen-lined ground squirrel, one of the most common small mammal species in shortgrass steppe at the Central Plains Experimental Range.

Paul Stapp handles a thirteen-lined ground squirrel, one of the most common small mammal species in shortgrass steppe at the Central Plains Experimental Range.

Our findings show that small mammalian herbivores had disproportionately large effects on plant communities relative to their small consumption of biomass.  Grazing by the combination of large and small herbivores favored recovery of short grasses after extreme droughts, providing resilience to the shortgrass steppe and contributing to the long-term maintenance of vegetation basal cover.  Our study expands prior work about small herbivores and demonstrates that even in small-seeded perennial grasslands with a long history of intensive grazing by large herbivores, non-colonial small mammalian herbivores should be recognized as an important driver of grassland structure and diversity.  Therefore, the importance of small herbivores was greater than initially thought and their effects on plant communities, isolated or in interaction with large herbivores, should be part of an integrated theory of how about herbivores influence grassland diversity.

Photo 5

Justin Derner sorts yearling steers for grazing experiments (and provides comedy relief) at the Central Plains Experimental Range.


Posted by: oikosasa | May 17, 2013

Habitat complexity, preys and predators

In the new Early View paper “Trait-mediated indirect interactions in a marine intertidal system as quantified by functional responses”, Mhairi E. Alexander and co-workers, have studied how factors as habitat compelxity affect predators and how the predators effect prey populations. Here’s their own summary:

It is well known that predation is important in community structure and functioning. It is also understood that the impact of a predator can be influenced by a number of biotic and abiotic factors. For example, the presence of higher-order predators can influence behaviours of intermediate species that can affect their consumption of prey through trait-mediated effects. Habitat complexity can also be an important mediating influence that in turn can influence the numbers of prey that are consumed. What is less well understood however is how these factors interact and contribute to prey population stability. In this study we address this by detecting and quantifying such trait-mediated indirect interactions (TMIIs) using functional responses, which consider a predator’s consumption over a range of prey densities, to investigate the implications for prey population regulation and stability,


We conducted several experiments to investigate how the influence of a higher-order fish predator combined with habitat complexity affects the behaviour of an intermediate amphipod predator from marine intertidal habitats. We first tested whether amphipods were able to determine higher-order predator presence. We found that amphipods demonstrated anti-predatory behaviour via a reduction in activity with the addition of cue that was seawater mixed with crushed conspecifics as well as seawater from tanks holding fish fed conspecifics and also those fed bloodworm. Interestingly, there was no reaction to fish fed an algal diet or those that had been starved. As we didn’t find any response of the basal prey, a commonly occurring isopod, to these cues, we went on to investigate how the presence of the cue in combination with habitat complexity affected the amphipods predation rates and whether the observed reduced activity translated into reduced foraging.


We observed that when there was no habitat or fish cue, amphipods showed what are considered to be potentially destabilising predatory responses towards the isopod prey. With the addition of habitat, however, the response was found to become stabilising as a result of a reduction in consumption of prey at low densities.  When habitat complexity was not included, the presence of fish cue was found to reduce the magnitude of the predator’s consumption of prey at higher densities, as would be expected with reduced activity in the presence of a predator. However when habitat was present in combination with fish cue, although reduced consumption occurred at low densities, at high prey densities it was increased in comparison to predation with habitat complexity and no cue. This seemed to occur as the fish cues drove the amphipods into habitat with more prey and thus actually enhanced predation of the basal prey.

The results from this study demonstrate the utility of functional responses in addressing questions of prey population stability. In addition we have further highlighted how complex predator-prey interactions can be, as well as exploring the relevance of environmental and biological cues that can result in unexpected and complex outcomes.

Posted by: oikosasa | May 14, 2013

Editor’s choice May

DriesOikos will publish synthetic meta-analyses open access and with high priority, and has assigned Christopher Lortie as deputee editor responsible for handling and inviting such contributions.  Jodi Price and Meelis Partel used meta-analyses to examine experimental evidence that functional similarity between invaders and resident communities reduces invasion. They found evidence for forb species but not for grasses, but equally important, their study highlights the fact that such patterns are more prominent in artificially assembled communities than in more natural communities with species or functional groups removed. Only by synthesing data from multiple studies the authors can unambiguously demonstrate that ecological mechanisms that are both theoretically and empirically underpinned may be only limited expressed under natural settings.

As a second editor’s choice we selected a theoretical study by Sonia Kefi and co-authors exploring to which degree critical slowing down is a key phenomenon to measure the distance to a tipping point in ecosystems. Tipping points are abrupt, unexpected and irreversible shifts within ecosystem. Specific ecosystem characteristics like spatiotemporal changes in biomass or population sizes may provide hints or early warning signals about an approaching shift. There is indeed a quickly expanding literature suggesting the presence of such early warning signals. By using analytical modelling, the authors demonstrate that -contrary to the ruling perspective- early warning signals based on critical slowing down are representative for a broader class of situations where systems experience increasingly sensitivity to perturbation. They are hence not solely specific to catastrophic shifts. This study consequently warns for a careful interpretation of critical slowing down as an early warning signal. It thereby stimulates further research aiming at developing and interpreting alike indicators to catastrophic ecosystem shifts whose occurrence may be extremely important for the livelihood of people living in such threatened ecosystems.

Editor’s Choice papers are freely accessible online for three months.

Posted by: oikosasa | May 7, 2013

Top of the pops

One of the most cited papers in Oikos, during 2011 (published 2009 and 2010) is “Life history tradeoffs influence mortality associated with the amphibian pathogen Batrachochytrium dendrobatidis”  Trenton W.J. Garner and co-workers. Here, Trent gives a short summary about the paper and tries to explain why it has been so important.


The chytridiomycete fungus Batrachochytrium dendrobatidis is a potentially lethal parasite of amphibians considered by many to be a primary factor behind global amphibian declines. It’s been associated with mass mortality and amphibian species decline on four continents and is the subject of a heck of a lot of research effort. However, at the time of the work, almost no published studies had attempted to test hypotheses developed from field observations of infection and mortality, and none had done so using both robust experimental design and multiple life history stages. The study was a real team effort, incorporating the results of extensive field work, multiple experiments and a concerted effort to isolate the parasite from field mortalities. While the results of experiments broadly supported the conclusions derived from field data (infection and death are predominantly related and Batrachochytrium dendrobatidis is likely the cause of post-metamorphic mass mortality events of common toads Bufo bufo in Spain), some previously unconsidered dynamics were revealed. We found that increased mortality was associated with weaker doses of the fungus, but often when infection did not appear to have occurred. We have since shown this to be the case in another amphibian species (Luquet et al 2012 Evolution).

Exactly how the risk of mortality can increase without detectable infection at time of death remains uncertain, but this is certainly different from what is seen in highly susceptible host species, where the burden of infection correlates positively with increased risk of death. As well in our study decoupling of infection from mortality was only detected in larvae. Previous to this, the tadpole stage was primarily overlooked as a stage susceptible to any substantial costs imposed by chytridiomycosis. This is because the parasite requires superficial keratinized tissue to proliferate, and this kind of keratin is only ubiquitously available on host anurans after metamorphosis, when the keratinized stratum corneum is fully developed. I think this may be the most interesting part of the study, that potentially lethal costs may be accrued by a host species even when the tissue that is the primary target for infection is still not fully available to the parasite.

For me one of the most satisfying outcomes of this study has been the ability to export the experimental methodology to other labs, which we have done through our EU-funded project RACE (Risk Assessment of Chytridiomycosis for Europe’s amphibians, Several researchers in several countries have benefitted from using techniques developed during this study, most importantly several graduate students. We’ve also employed our experimental system to explore relationships between climate change and chytridiomycosis (Garner et al. 2011 Global Change Biology) and investigate the evolution of the fungus itself (Fisher et al. 2009 Mol Ecol, Farrer et al. 2011 PNAS). In doing so, I believe we’ve been able to shine some light on the rather unpredictable and context-dependent relationships between Batrachochytrium dendrobatidis and amphibian hosts that are not highly susceptible to chytridiomycosis, but may still experience the lethal form of the disease.

We use cell culture flasks to house tadpoles individually through metamorphosis. This system allows us to replicate extensively while keeping the individual animal the unit of replication. Replicating treatments 30 or 40 times is easily achievable for most experiments using this approach. Not bad for a vertebrate.

We use cell culture flasks to house tadpoles individually through metamorphosis. This system allows us to replicate extensively while keeping the individual animal the unit of replication. Replicating treatments 30 or 40 times is easily achievable for most experiments using this approach. Not bad for a vertebrate.


Posted by: oikosasa | May 6, 2013

Oikos at INTECOL

INTECOL 2013, takes place in London August 18-23, see

We’ll be there! Will you?

More info on Oikos symposium and other activities will come soon!

The 11th INTECOL Congress, Ecology: Into the next 100 years will be held in London as part of the centenary celebrations of the British Ecological Society.The theme of the Congress is Advancing ecology and making it count.

Early-bird registration closes on 12th May:

Read about butterflies finding romance in the mountains in the new Early View paper “Simple rules for complex landscapes: the case of hilltopping movements and topography” by Guy Peer and colleagues. here’s Guy’s summary of the paper:

Mating on a hilltop

Mating on a hilltop

You are lost in an unfamiliar, hilly landscape. What shall you do? Most people would ascend the nearest hill and try to get a good overview. Butterflies may have much more limited vision, but they manage quite effectively in aggregating on mountain tops which serve as rendezvous for mating. An individual-based model which focuses on this “hilltopping” phenomenon identifies simple behavioural rules that can optimise mating success, and the success of mated females in finding habitat patches, across landscapes regardless of their complexity. One interesting rule is: when moving uphill, butterflies should respond strongly but not ‘perfectly’ to topography. A perfect response, without occasional random movements, would simply trap them on local summits. If such mild randomness might be adaptive, shall we adopt the rule and accept our imperfections? At least for butterflies, it clearly helps finding a mate.

Fighting overe a female on a hilltop

Fighting overe a female on a hilltop

Guy Pe’er when chasing hilltopping butterflies in Israel, long ago when doing his PhD. While his “hilltopping model” is by now 12 years old, new results continue to emerge.

Guy Pe’er when chasing hilltopping butterflies in Israel, long ago when doing his PhD. While his “hilltopping model” is by now 12 years old, new results continue to emerge.
Posted by: oikosasa | April 23, 2013

The zombie killing spree continues

Look up, zombies are all around us nowadays! Even within science! In the Early View paper  “A critical analysis of the ubiquity of linear local–regional richness relationships“, Thiago Goncales-Souza and colleagues  goes on a zombie-killing adventure. Here is there summary of the paper:

Recently, ecologists have gone on a zombie killing spree, started by a blog post of Jeremy Fox here at the Oikos blog (link here). Dr. Fox defined zombie idea as having “survived decades of attacks from the theoretical and experimental equivalents of chainsaws and shotguns, only to return to feed on the brains of new generations of students.” He featured other zombie ideas such as “neutral = dispersal limitations” and the unimodal diversity productivity relationship. The post on his original zombie idea actually resulted in a peer-reviewed publication (Fox 2013) that, in his own words, has “No zombie jokes or other inflammatory rhetoric in it. I leave it you to judge if that makes the paper better or worse than the blog posts.” (link here).

We think that our publication fits into this zombie killing tradition. One of the most fundamental interests of ecologists since the early development of the ecological theory is the understanding of (potential) processes that drive local community structure. At a fundamental level, communities are structured by a combination of local environmental and regional processes (Ricklefs 1987).  The easiest and most traditional way to test whether regional or local processes affect local community structure consists of regressing local against regional species richness (the famous LSR-RSR relationships). The argument goes that communities controlled by regional processes are considered unsaturated, whereas communities controlled by local processes (such as species interactions) are considered saturated. Sadly enough, this argument survived indeed decades of attack (D. Srivastava, F. He and collaborators, and H. Hillebrand).

Sadder still, this method has kept on feeding on the brains of new generations of students, since it is used and featured prominently in ecology textbooks such as Begon et al. (Ecology: from individuals to ecosystems), Krebs (Ecology: the experimental analysis of distribution and abundance), and Ricklefs (The Economy of Nature and Ecology). Probably every ecology student has heard about the ubiquity of regional processes as drivers of local community structure using this method.

In addition to these fundamental problems, Szava-Kovats and collaborators in Oikos showed that the statistical test for detecting the linearity of the relationship is biased towards linear relationships, and moreover provided an unbiased method (called log-ratio method). In this Forum paper, we reevaluated the evidence for the ubiquity of linear LSR-RSR relationships by comparing the biased conclusions with the unbiased method, and found:

  1. In 113 relationships found in 47 studies, 70% and 30% were considered unsaturated and saturated, respectively, when using the biased method. However, by using the unbiased log-ratio method we found no prevalence of either unsaturated (53%) or saturated (47%) communities (Figure 1);
  2. 40% of the studies using the biased method were misclassified (i.e., mistakenly found an unsaturated pattern when it was saturated or vice-versa) and thus reached wrong conclusions.
  3. 50% of the examples of LSR-RSR relationships used in four (classic) ecology textbooks were misclassified.

Our conclusions thus add a new weapon in the arsenal against the zombie idea of interpreting local-regional relationships based on the linearity of the relationship. We showed that the last argument in favor of the method (its ubiquity) was based on a biased statistical method. We argue instead that future studies should consider the reciprocal interactions between regional and local such as those that take advantage of the metacommunity theory to understand the relative influence of regional and local processes on local community.

While studies of LSR-RSR relationships were instrumental to the development of the ecological curriculum, we hope that we can now finally put this zombie idea to rest and move on. As a final note, one of the reviewers for this manuscript was … non other than Jeremy Fox, zombie slayer par excellence.


Posted by: oikosasa | April 18, 2013

Welcome Susan Harrison – new SE

We are very happy to welcome Prof. Susan Harrison from UC Davies, USA, to our editorial board.
 susan at sensitive plant canyon 

My research seeks to understand the processes that shape and maintain plant species diversity at the landscape scale, where small-scale forces such as competition and facilitation interact with large-scale forces such as niche evolution and dispersal.  In the past few years, one particular focus has been to understand what characteristics of plant species and communities make them more or less susceptible to climate change, as well as to other interacting perturbations like fire, grazing, and invasion.  We’ve found that plant communities on nutrient-poor serpentine soils seem to respond less strongly to natural and experimental climatic variation than other communities, but we don’t yet understand the roles of soil properties, plant traits, and emergent community properties in causing this pattern.

Read more:

GG burn wildflowers 7
Posted by: oikosasa | April 16, 2013

Same, same but oh so different.

They look the same, but perform so differently. And act differently against each other. Cryptic amphipods are dealt with in the Early View paper “Phenotypically similar but ecologically distinct: differences in competitive ability and predation risk among amphipods” by Rickey D. Cothran and colleagues. Read their summary here:

Traditionally, species that look alike were thought to be unlikely co-inhabitants due to competitive exclusion. However, newer theory suggests that a mix of ecological similarity that limits performance asymmetries that lead to competitive exclusion and slight differences in niche use may maintain species diversity. We provide data on the relative competitive ability and predation risk for three amphipod species that co-occur in lakes in North America. Until recently, these species were only differentiated using molecular markers (see picture). We discovered that slight differences in phenotype lead to differences in how well these species compete and deal with predators. We also found that the two species that show the strongest overlap in distribution within lakes are very similar when it comes to their competitive ability and predation risk. Our work suggests that a mix of niche differentiation and ecological similarity are maintaining amphipod species diversity in lakes.

 Cryptic amphipod species before (top) and after (bottom) preservation in 70% ethanol. From left to right: species A, species B, and species C. All animals are females.

Cryptic amphipod species before (top) and after (bottom) preservation in 70% ethanol. From left to right: species A, species B, and species C. All animals are females.

Picture caption: Cryptic amphipod species before (top) and after (bottom) preservation in 70% ethanol. From left to right: species A, species B, and species C. All animals are females.

Posted by: oikosasa | April 11, 2013

Taking metacommunity models to the empirical world

Will the use of “real” connectivity between communities improve metacommunity models? Read more in C.Moritz and colleague’s Early View paper: “Disentangling the role of connectivity, environmental filtering, and spatial structure on metacommunity dynamics”. Here’s their summary of the paper:

For decades, the environment has been proven to structure biodiversity. However, dispersal of organisms is also  a process that helps structuring and maintaining biodiversity in local communities. The problem is that  connectivity between communities (the fact that these communities are linked, resulting from the dispersal  process) is often assessed using a more or less simple function of geographic distance. Theoretical metacommunity models can incorporate both environmental and dispersal processes, but empirical  studies considering real connectivity instead of a function of geographic distance are more scarce. In our work,  we have included real connectivity measures to analyse polychaete community structure in the Gulf of Lions (NW  Mediterranean Sea) at different spatial scales. Our results are not trivial…and equivalent methods should be  applied to other ecosystems (terrestrial or marine) to continue quantifying the importance of dispersal on  biodiversity, either for particular species of interest or for entire communities.


Posted by: oikosasa | April 9, 2013

When plants help other plants…

Nice to see that nature provides other kinds of interactions than nasty predation, competetion and parasitism! Christian Schöb and coworkers have studied the importance of “nursing” plants – plants that fascilitate for other plants – in community ecology. Read their Early View paper “Direct and indirect interactions co-determine species composition in nurse plant systems”.

Here is a summary of their study:

Our motivation to build a framework based on observational data in order to disentangle direct nurse effects from indirect effects among beneficiary species was twofold:

1) In some very common nurse plant systems, such as alpine cushion plant communities, the removal of the nurse to eliminate the direct effect and unambiguously estimate interactions among beneficiary species is simply not feasible.


The physical removal of the nurse cushion Arenaria tetraquetra ssp. amabilis growing in the Sierra Nevada Mountains in Spain would destroy the beneficiary species growing within the cushion canopy; in particular because beneficiary species often root in the organic matter accrued under the cushion.

2) Even in nurse plant systems where the physical removal of the nurse is feasible, taking away aboveground nurse parts does not remove the permanent effects of the nurse, e.g. the effects on soil properties including texture, resources and microbial communities.

An intact Retama sphaerocarpa nurse plant system in the semi-arid lowland of southeastern Spain with the nurse shrub and its understory community of beneficiary species.

An intact Retama sphaerocarpa nurse plant system in the semi-arid lowland of southeastern Spain with the nurse shrub and its understory community of beneficiary species.

The removal of aboveground parts would not remove the whole effect the nurse shrub, such as accumulation of soil organic matter and its specific communities of soil bacteria and fungi, which all together influence beneficiary species even after the nurse plant has been removed.


In our article we propose a simple but powerful mathematical framework to take apart direct effects of the nurse on its associated community from effects of interactions among beneficiary species. Our results showed facilitative effects of the nurse on its beneficiary species whereas interactions among beneficiary species where mostly competitive. Both interactions contributed significantly to the composition of the beneficiary plant community even though the direct nurse effect was ca. five times stronger than the effect of the interactions among beneficiary species. Interestingly, these patterns where similar in the two nurse plant systems studied even though they differed considerably in abiotic conditions (high alpine vs. semi-arid lowland) and growth form of the nurse (cushion plant vs. shrub). Our data therefore indicate functional parallelism of different nurse plant systems and highlight the complexity of species interactions within plant communities.

Hello everyone, my name is Ross Boucek and I am PhD student at Florida International University. Oikos has asked me to write about our Early View paper “No free lunch: displaced marsh consumers regulate a prey subsidy to an estuarine consumer” where we investigate the value of food subsidies to recipient consumers as well as what controls the amount of food subsidies available to them.  Food subsidies are resources that enter an ecosystem from another place, and add on to the resource base that is already available within the system. Subsidies in some instances can be almost considered a bonus, like getting cash for your birthday in the mail.  If you are on a graduate student stipend, birthday cash subsidies can go a long way! Because of the predictability of birthday cash, many graduate students budget these cash bonuses into their spending well before they arrive.  Therefore, if for some reason these checks get lost in the mail, or they are for less money, we could be in some trouble!

Graduate students and their reliance on birthday money is very similar to how some animals rely on food subsidies to survive.  One particularly charismatic example of consumer-subsidy interaction is bears and salmon in the U.S. Pacific Northwest.  In the fall, these bears congregate around rivers and streams to gorge themselves on salmon that predictably migrate from the oceans to spawn. These salmon subsidies help bears build necessary fat reserves that play a major role in their survival and reproduction over the winter. Because of the importance of food subsidies to consumers, biologists and ecologists have gone to great lengths to identify where subsidies occur in nature, and more importantly what controls how much of the food subsidies reach recipient consumers.


Diagram of the relationship between marine salmon subsidies and bears

Moving back to the bear-salmon subsidy interaction, in some areas of the U.S. Pacific Northwest, sea lions have figured out salmon are easy prey during their spawning migration; such that some sea lions track salmon up rivers, and pig out on these spawning fish, preventing them from reaching bears. The interception of these salmon subsidies by sea lions can be so intense, that they can reduce salmon available to hungry bears waiting upstream by as much as 65%.

Boucek 2

Diagram showing how sea lions reduce salmon subsidies to bears

This brings me to my research.  I work in the Florida Everglades, more specifically, where the iconic Everglades marshes or the “river of grass” joins the beautiful tropical mangrove estuary.


The study area of our research, located at the marsh-estuary interface in the Southwest Everglades

At this interface between the marsh and the estuary, during the winter and spring, rainfall decreases, causing freshwater marshes to dry.  When these marshes dry, large numbers of small-bodied freshwater fishes are forced into the estuary. At the same time that these prey enter the estuary, estuarine fish predators triple in abundance presumably to gorge on the marsh fish prey forced into the estuary.  Thus at the Everglades ecotone, estuarine predators function similarly to the bears in the Pacific Northwest, and small bodied marsh prey are like the salmon. However, similar to the sea lions, these small bodied fishes are accompanied by large-bodied fish predators that also live in the marsh that can intercept and remove or reduce fish prey subsidies to the estuarine consumers.  With all of this in mind, my research questions were 1) how important are marsh prey subsidies to estuarine consumers? And 2) how much of this subsidy is being removed by marsh predators?


Boucek 5

Diagram showing the relationsship between estuarine and marsh predators and marsh prey subsidies at the marsh-estuarine interface of the southwest Everglades

Our results show, like the salmon-bear example, that estuarine predators gorge themselves on these marsh prey subsidies. Consequently, the consumption of this subsidy makes estuarine predators roughly 15% fatter than they were before.

However, like the sea lion example, freshwater marsh predators consume about 60% of the fish prey that enter the estuary, leaving only 40% for the estuarine consumers.   The regulation of this subsidy to snook, the estuarine predator, could influence how much energy snook allocate to reproduction each year.  Snook spawn in the early summer to mid fall. Therefore the weight snook gain from this subsidy in the spring could go to egg production in the summer, thus increasing reproductive output.  If marsh predators decrease in abundance, then the amount of subsidy available to snook could increase, which may allow snook to invest more energy into reproduction and increase spawning success.  My current research is investigating just this question, whether or not larger prey subsidies, facilitated by the loss of marsh predators, result in increased spawning effort by snook.

Understanding the dynamics behind this subsidy could have important implications for South Florida.  In South Florida, snook are an important recreationally sought after fish.  In fact, snook are the 5th most targeted fish in the entire east coast of the United States, despite only occurring in South Florida. The money spent from anglers fishing for snook generates substantial amount of revenue for local businesses.  Therefore, knowing the drivers behind snook population dynamics like the regulation of food subsidies will help us better understand the provisioning of ecosystem services such as fisheries in the Everglades.


Posted by: oikosasa | April 2, 2013

Large-scale testing of Bergman’s rule

The colder, the bigger, suggested Bergman in 1848. In 2013 we publish a paper testing Bergman’s rule on a large data set. Showing…well find out in “Bergmann′s rule in mammals: a cross-species interspecific pattern” by Marcus Clauss and his co-workers. Below is their background story to the study:

I first learnt about ‘Bergmann’s rule’ (that among closely related species, those living at higher latitudes/at colder temperatures are larger) in school. It was one of the biological facts I had always considered a background fact that is unquestioned.  

When preparing a manuscript on the reproductive seasonality of ruminants (Zerbe et al., 2012) we collated various biological data on ruminants, including body mass and mid-latitude of their geographical range, and before testing relationships of these data with our proxy for seasonality, we tested them amongst themselves for potential correlations. We did this without accounting for the phylogenetic structure of the data (ordinary least squares) and with such an accounting (phylogenetic generalized least squares, pgls).


We were not surprised when we found a relationship between latitude and body mass in our phylogenetic analysis – because this simply reflected Bergmann’s rule. The fact that this relationship was not significant in conventional statistics, but significant in pgls, just supported the notion that the rule holds among closely related species, not just any species you lump together. For us, this was a minor side-dish result in our set of analyses, and one we were not excited about, because it simply confirmed what we knew from school. In a quite similar way, our ruminant dataset supported, for example, Rensch’s rule (which was cool for our co-author that had the same name). But when we prepared the manuscript, and searched for other papers to cite in connection with our side result, we realized that Bergmann’s rule had, as far as we could find, not been analysed in this fashion among mammal species, not in ruminants, and surely not in a larger mammal dataset. Literature on Bergmann’s rule in mammals most often dealt with the intra-specific side of the phenomenon or with mammal assemblages, but not on the taxonomic/interspecific level. So we expanded the dataset beyond the ruminant species for which we had seasonality data, to comprise all mammals (based on availability of data in the PanTheria database). Again, we found the same effect: the relationship between latitude and body mass was significant if the phylogenetic structure of the dataset was taken into account. In a sense, we felt like having found a simple proof for a school lesson that had not been provided so far. This does not mean we claim to be first, best, closest, whatever, to proving Bergmann’s rule – we just found a simple, maybe elegant way to demonstrate it. Actually, once you start looking at individual taxonomic subgroups or certain geographic ranges, the picture becomes less simple – but that’s in the paper.  

For us, several lessons came with working on this topic. One is that the statistical procedure (pgls, sometimes called ‘phylogenetically controlled statistics’) is not only a quarrelsome one that one has to apply nowadays to get a paper published, but actually facilitates, in special circumstances, the detection of a pattern that would not be evident from simply plotting the data, or from ‘conventional’ statistics. So we tried to understand how patterns would look that yield different results in conventional and phylogeny-informed statistics, drawing on textbooks on the matter, and produced some schematic graphs to get a mental grasp on this (provided as a supplement to our paper). In my experience, there are quite some examples where a relationship that is significant in conventional statistics is no longer so in phylogenetic statistics (which then needs to be interpreted), but there are very few examples where a relationship is not significant in conventional stats but clearly is in phylo-stats.  

The other lesson came from going through the literature – at some stage, we decided to try to locate the original source itself, Bergmann’s own account, which was sometimes described as ‘hard to get at’ – and were surprised that you could simply download the whole text from the net (it is now part of the google books resource pool). Reading this text was quite some fun, due to the old style it was written in. From other literature, we had gained the impression that Bergmann formulated his rule for mammals, and were therefore surprised to see that he actually developed it, and supported it, using birds. And all the examples Bergmann used himself were between, not within, bird species, so no need to debate whether he meant it on an inter- or intra-specific level. Because the text is written in German, we decided to provide a relatively detailed translation of larger parts of it, so that others could get a picture of how he built his argument. I personally especially cherished his concluding comment, where he cautions the reader that in trying to support his hypothesis, he might have looked at the actual evidence in a biased way, and that therefore independent tests would be welcome.    

Posted by: oikosasa | March 28, 2013

Editor’s choice April 2013

DriesFor the April issue, we chose the following two papers as editor’s choice according to our motto of synthesizing ecology. Mumby et al. (2013) discuss various articles that either support or reject the hypothesis that coral reefs might be able to exist under certain conditions in two alternative stable states (ASS): a coral-dominated and a macroalgae-dominated state. Given the fact that the existence of multiple attractors is controversial, synthesis needs to be created by compiling various forms of evidence. Mumby and colleagues provide such an overview of evidence by providing analyses of the literature and the available empirical and theoretical data. By means of this integrated approach, they conclude that the most compelling evidence, which combines ecological models and field data, is far more consistent with multiple attractors than the competing hypothesis of only a single, coral attractor. This message warns managers that degraded reeds might never be able to be restored once dominated by macro-algae. Read Peter Mumby’s summary of the paper here

The second paper we selected is Baiser et al. (2013) testing the ability of metacommunity models to predict the network structure of the aquatic food web found in the leaves of the northern pitcher plant Sarracenia purpurea. It is the central aim of metacommunity theory to elucidate the relative impact of local and regional processes on local community structure. The structuring processes have, however, been predominately inferred from statistical modelling. The work of Baiser and colleagues takes an elegant approach to formally test to which degree patch-dynamics, species-sorting, mass-effects, and neutral metacommunity models, as well as three hybrid ones are able to predict observed patterns of the aquatic foodweb structure within these plants. By merging empirical data and more mechanistic models they test the probability that dispersal and sorting processes are important mediators of food web structure. While such integrated empirical-theoretical approaches have been developed for other ecological questions, Baiser et al. here demonstrate its usefulness for understanding drivers of food web structure.

Both papers as Open Access.

Posted by: oikosasa | March 26, 2013

New Oikos Cover!!

From the April issue 2013 onwards, Oikos will have a photo illustrating ecology in action on it’s cover.

To find the right photo for this year’s cover, we had a photo competition during winter. The happy winner of the competetion is Sascha Rösner, Marburg, Deutschland. See more of his photos here:

And here is our new cover:


And here, Sascha tells us how he took the winning photo:

Wildlife photography often entails long travels to distant and remote landscapes that harbour a particular species of interest. This picture of two sawfly caterpillars (Nematus spec.), however, was taken just three meters of the front door of the photographer’s home. In the front yard, a small willow tree (Salix spec.) was densely populated with hundreds of these caterpillars. An easy opportunity to take the camera from indoors, attach a macro lens to the camera, mount it on a tripod, and take pictures (in fact, still wearing slippers). By chance, two of these guys apparently fed synchronously in the center of a leaf. Within 24 hours, the tree was completely naked, the caterpillars “abseiled” to the ground, and dug into the soil where they would morph into the imago flies some weeks later. Canon EOS 20D, EF 100 mm 2.8 @ f 7.1, ISO 100, tripod, remote control.

Posted by: oikosasa | March 22, 2013

Time to get rid of the males?

It has been debated for a while…are males really necessary? Find out how fish of the genus Chrosomus solve the small problems associated with asexual reproduction, in the Early View paper “Diets of sexual and sperm-dependent asexual dace (Chrosomus spp.): relevance to niche differentiation and mate choice hypotheses for coexistence” by Jonathan A Mee and co-workers.

Here’s a short summary of the study:

In order to persist, sperm-dependent asexuals must be ecologically divergent and/or more sperm-limited compared to their sexually reproducing hosts.

It’s easy to be fascinated by sperm-dependent asexual species – they’re one of those oddities of natural history that, collectively, are the reason many of us became students of biology. These all-female “Amazons” require a male (or just their sperm) of a sexually reproducing host species to provide the trigger for egg development and reproduction, but, in most cases, discard the male’s genome.

In addition to being a fascinating natural oddity, the existence of sperm-dependent asexuals raises an interesting scientific question: how do sperm-dependent asexuals coexist with their host species?  All-female asexuals have a great advantage over sexuals – by producing no males, the asexuals have twice the potential population growth rate relative to the sexuals.  But, in the case of sperm-dependent asexuals, vastly outcompeting the sexuals (i.e., eliminating the source of sperm) would eliminate the ability to reproduce.  There are two general mechanisms by which sperm-dependent asexuals and their sexual hosts can achieve stable coexistence.  First, sufficient ecological divergence between the sexuals and asexuals would avoid competitive exclusion.  Second, if males prefer mating with sexual females rather than asexual females, asexual females would be more sperm limited (and have reduced reproductive output) relative to sexual females.

blog eos

Our contribution to understanding how sperm-dependent asexuals coexist with their sexual hosts examined the combined influence of these two mechanisms (ecological divergence and male mate choice) on the coexistence of sperm-dependent asexual species and their sexual hosts – previous work only considered each mechanism independently. We integrated the insights of mathematical modeling and empirical data on ecological divergence (from two natural populations of the sperm-dependent asexual fish, Chrosomus eos-neogaeus) to conclude that a combination of both mechanisms may be required for coexistence. This integrated approach is valuable to understanding many ecological and evolutionary processes.

blog figure

Posted by: oikosasa | March 19, 2013

On the evolution of fruit colour

Ever thought about why an orange is orange while an apple is green? And a blueberry blue and blackberry black, while a raspberry is red? Well, one explanation – seasonality – is studied in the new Early View Paper  “Fruit color and contrast in seasonal habitats – a case study from a cerrado savanna” by Maria Gabriela G. Camargo and co-workers. Here is their short summary of the study:


Examples of fruits with different colors. A. green; B. multicolored; C. yellow; D. black; E. multicolored; F. brown; G. multicolored; H. red.

Fruit color is an important signal for diurnal seed dispersers, mainly for birds, and the contrast between the fruit and the background is regarded as more important than the color per se for fruit detectability. However, the contrast between fruit displays and their background are not necessarily constant in seasonal habitats where part of leaves is shed in the dry season.

We thus hypothesized that the contrast between fruit displays and their background vary throughout the year in a seasonal habitat and if this variation is adaptive, we predicted higher contrasts between fruits and foliage during the fruiting season.

To verify our hypotheses we used reflectance measurements of fruits and leaves and contrast analysis. We also accessed a six-year data base of fruit ripening according to the fruit color (red, yellow, black, brown and multicolored) for a woody community in a cerrado-savanna vegetation, southeastern Brazil. The cerrado is subjected to a seasonal climate, with a wet summer between October and March and a dry winter between April and September, when the leaf background get yellowish.


Circular histograms for the frequency of fruiting onset dates per fruit colors in a woody cerrado savanna community, southeastern Brazil.

We found that black, and particularly red fruits, that have a high contrast against the leaf background, were highly seasonal, peaking in the wet season. Multicolored and yellow fruits were less seasonal, not limited to one season, with a bimodal pattern for yellow ones, represented by two peaks, one in each season. We further supported the hypothesis that seasonal changes in fruit contrasts can be adaptive because fruits contrasted more strongly against their own foliage in the wet season, when most fruits are ripe. Hence, the seasonal variation in fruit colors observed in the cerrado-savanna may be, at least partly, explicable as an adaptation to ensure high conspicuousness to seed dispersers.


Mean leaf reflectance curves during the dry and wet seasons for 49 species of the woody cerrado savanna community, Southeastern Brazil.

To consider at your Friday dinner tonight: Sex-biased diets affect the ecology of other species in the surroundings. Read more in the new early View paper “Antelope mating strategies facilitate invasion of grasslands by a woody weed” by Shivani Jadeja and colleagues. To get a good feeling of the antelope and the seeds that the males eat, read Shivani’s beautiful description of the wildlife reserve in western India, in her summary of the paper:


Mesquite (Prosopis juliflora) pods

In Velavadar National Park, a grassland wildlife reserve in western India, invasive mesquite trees (Prosopis juliflora) obstruct the horizon, where the land meets the sky. The dominant woody plant in the area, mesquite juts out as green crowns among the drying grasses that give the grassland a hue of yellow, red and olive streaks in the winter and summer. Velavadar is home to a large population of the threatened native antelope, blackbuck (Antilope cervicapra). Male blackbuck defend territories in open grasslands; these territories are either solitary or in clusters called leks. The classical lek in Velavadar, the size of a football field, may have more than ninety rutting males during peak mating season. During this time, the lek turns into a battle field where males perform strenuous displays and engage in fierce fights to defend their territories. Females visit the lek and seem to use a variety of information to choose a male to mate with. Males use urine and dung to create huge scent marks on their territories. These dung-piles can be seen as black dots from outer space (Look at blackbuck dung-piles on Google satellite images at 22° 2’54.82″N and 72° 1’20.78″E).


Fruit removal by male blackbuck (Antilope cervicapra) captured in a camera trap

3_Seed deposition through dung on a male mating territory- Inset- Large dung-pile on the classical lek

Seed deposition through dung on a male blackbuck mating territory. Inset: A large dung-pile on the classical lek


Presence of mesquite seeds in blackbuck dung

As blackbuck prefer open habitats, we predict that this concentrated seed dispersal by males will result in a positive feedback process where territories, which are typically in open grasslands, are modified into woodland patches, following which  males shift their territories to more open areas. We also predict that this male-aided conversion of grasslands to mesquite woodlands will negatively affect this open plains antelope species and cause shifts in mating system and social organization and a reduction in population size. Thus, here is one mechanism of spread of a woody invasive in grasslands, where one sex of a disperser, here male blackbuck, through its extreme mating behaviour, is planting seeds in new habitat, and perhaps negatively affecting its own lifestyle.


Seedling growing in a dung-pile on a blackbuck mating territory

Posted by: oikosasa | March 12, 2013

The little black dress of ecology

Taylor´s power law and bird populations are studied with in the new Early View paper “Interspecific differences in stochastic population dynamics explains variation in Taylor’s temporal power law”, by Marit Linnerud and her coworkers. Here’s Marit’s summary of the study:

Taylor’s power law – an oldie but goodie!

Taylor’s power law is like the little black dress of ecology, a general law that fits every species regardless of size or other personal characteristics.  According to the law the variance of population abundance in either time or space can be described by a function of the mean. A reasonable null expectation following from the definition of the variance is that as the abundance of a population increase by one unit on a logarithmic scale the variance is expected to increase by two logarithmic units, resulting in a slope of two. However, empirically the slope is often less than two, thus revealing some interesting ecological dynamics. Although the causal mechanism behind the law is not agreed upon, it seems likely that several factors are at play. A theoretical framework based on stochastic population dynamics provides testable predictions of what causes the deviations from the expected slope of two.

In our recent study we estimate the temporal mean-variance relationship for a large number of British bird populations. There were two significant challenges. Firstly, we could not ignore that sampling in itself could bias the estimates of the variance and secondly the estimated of variance increases with the number of years the population have been studied. Taking this into account we evaluated how the different deterministic and stochastic factors known to affect temporal population dynamic influenced the slope of the power law. It turns out that differences in demographic stochasticity among species were the main explanation of the variation in the slopes of Taylor’s power law.

Posted by: oikosasa | March 8, 2013

Cocktail mingle ecology

I would so much like to see someone using Hari Sridhar, Ferenc Jordán and Kartik Shankers paper “Species importance in a heterospecific foraging association network” as a basis for a study of humans on cocktail parties. Which small groups may be the core of highly important individuals (instead of species)? Is the same group of people important if they go to a party in another place? Or to a scientific conference in another research area? Or are humans not at all like birds?

Here is Hari’s background story to the study. The beautiful drawing is made by Rangu Narayan.

Chance and luck played a big part in the making of this paper. It was early 2008, and I had just begun my doctoral work on mixed-species bird flocks, when Ferenc visited my department. Ferenc specializes in using network approaches to tackle problems in ecology. In a talk during his visit, he mentioned that ‘network thinking’ was particularly useful in two ecological contexts: (1) to understand interactions among individuals in animal social groups (2) to understand interactions among species in communities, e.g. foodwebs. When we heard this, both Kartik (my PhD supervisor) and I immediately realized the value of network thinking in my doctoral work because mixed-species flocks fit both the contexts that Ferenc highlighted. Each mixed-species flock is a social group built on interactions among individuals of different species; but across multiple such flocks in an area, populations of species are linked in a community-level species interaction network. We spoke to Ferenc and he readily agreed to help us, since he too was keen on trying his hand at a new ecological system.  Given our different geographical locations (Ferenc was based in Trento, Italy, and Kartik and I in Bangalore, India), the plan was to work the collaboration entirely over email. But another lucky break meant that I could go to Ferenc’s institute in Italy to work on the project. My fieldwork was supported by a grant from the International Foundation for Science (IFS), of which a large portion remained unused till the end.  IFS allowed me to use this money to travel to Italy for two weeks in early 2012. Over endless cups of coffee and food at an Indian (!) restaurant in Trento, Ferenc and I built and analysed the flock networks for this paper.


 This collaboration had other useful spinoffs. Ferenc came back to India in 2012 to conduct a network analysis workshop as part of a student conservation conference in Bangalore that Kartik and I were involved in organizing. Kartik and Ferenc are also putting together a special issue on ecological networks for a conservation magazine called Current Conservation, which will include a non-technical piece based on this Oikos paper.

Posted by: oikosasa | March 7, 2013

Theoretical weed ecology

Do you like trying new food items? I do. And many herbivore insects seem to do so as well. Invading alien species, yummy yummy! How these interactions affect the ecology of the invaders is studied by Matthew L. Forrister and Joseph S. Wilson in “The population ecology of novel plant–herbivore interactions”. Here’s their background to the study:

Everyone knows that weeds are everywhere these days, and most ecologists know that native insects often like to eat exotic plants.  That dynamic (native herbivores utilizing novel hosts) has been very productive for evolutionary biologists (think about the apple maggot fly on apple or the soapberry bug on goldenrain trees), and has become increasingly useful for ecologists who realize that we can watch novel interactions and communities assemble before our eyes.


The ubiquity of interactions between native herbivores and novel plants has led to an imbalance in the ratio of empirical to theoretical work.  Moreover, some of the relevant theoretical work (for example on the evolution of niche width) is not always accessible to the average field biologist observing caterpillars eating weeds.  Our motivation in writing this paper was to provide an easily accessible conceptual framework that might serve to organize and focus experimental approaches.  For example, studies are often reported in which the “preference-performance” relationship is examined using native insects reared on native and exotic hosts.  We believe that the focus on that particular relationship demonstrates a certain inertia in the literature that should be overcome, because (for one thing) a rather definitive meta-analysis of that issue has been recently published (Gripenberg et al. 2010 Ecology Letters 13:383-393), and moreover there are many other facets of insect life history that need to be studied, such as interactions with natural enemies, indirect interactions with other herbivores or behavioral factors that affect realized fecundity.

In addition to making the rather fundamental point that our studies need to go beyond the performance of juvenile herbivores and the preference of ovipositing females, we offer some hypotheses to challenge assumptions and spur future work.  We present our hypotheses in qualitative, graphical format in the spirit of the late Robert MacArthur.  Some quantitatively-sophisticated readers might find this approach simplistic, but we hope that other readers will find it useful.  For example, we ask about the shape of the relationship between dispersal ability, population growth rate on a novel host, and the rate at which a new host is utilized.  Also in the spirit of MacArthur, we hope that other researchers will be inspired to propose alternative hypotheses, which is something that we believe the graphical (as opposed to verbal) format encourages.

Posted by: oikosasa | March 5, 2013

Can we trust field-guides in ecological studies?

How consistent are field-guides and atlases? Enough to be used as sources in ecological research studies? Jay Fitzsimmons has checked and has the answer! Find out in his new Early View paper “How consistent are trait data between sources? A quantitative assessment”. Below he tells us what made him conduct the study:

Compare all the sources meme

I compared several field guides and atlases to see whether they were consistent in what they said about species’ traits.  The proximate reason why I did this research is that, given the popularity of trait-based research, I wanted to determine how consistent trait data were among authoritative sources.  The ultimate reason why I did this research is that I’m a paranoid city slicker who worries over how little I know about my study species.

Trait-based ecology is increasingly popular, with researchers evaluating whether species’ traits are related to a variety of ecological factors (e.g., extinction risk, invasiveness).  In my PhD I did such an analysis myself, evaluating the relationship between butterfly species’ traits and their rates of northward range shift in Canada over the 1900s (not yet published – it’s only been two weeks since my PhD ended so give me a break).  The advice given to me on how to obtain species’ trait data was “just use an atlas or a field guide.”  This is when my paranoia alarm started ringing.  Which atlas or field guide should I use?  Do they all say the same thing?

 While I love and respect natural history (I volunteer as Journal Manager for The Canadian Field-Naturalist –, I am not a great naturalist myself.  I cannot even identify most of Canada’s butterflies, never mind critically evaluate the accuracy of their trait data.  This is a serious problem for macroecology that isn’t given the critical attention it deserves: researchers using fancy models and elaborate analyses can miss critical issues if they don’t know the natural history of their study species.  Non-naturalist macroecologists can miss interesting results that merit follow-up, or wonky results that could indicate coding errors.

 So which source should a paranoid, butterfly-ignorant macroecologist use?  All the sources of course!  Ok, not all the sources (not by a long shot), but I used five authoritative sources authored by recognized experts.  I entered data from each source for 22 traits for 263 Canadian butterfly species.  I compared trait data for species across sources: do different sources say the same things about species?  I found some traits to be very consistent across sources, and others worryingly inconsistent.  In general it seems that subjective traits (e.g., habitat association) were less consistent than more clearly-defined traits (e.g., wingspan, over-winter stage).  This suggests results from single-source trait studies may depend in part on which source was used for trait data.

It was a pleasure to do this work, and to vindicate my paranoia (I can put the tinfoil hat away for another day).  I hope others do similar comparisons of field guides and atlases for other taxa and regions to reveal how general my findings are, and what effect such inconsistency has on trait-based research results.

How do animals decide how to forage? In the new Early View paper “How a simple adaptive foraging strategy can lead to emergent home ranges and increased food intake” Jacob Nabe-Nielsen and colleagues demonstrate that it only requires a few simple behavioural rules to produce most of the complex movement patterns observed for harbour porpoises.

What is it that makes an animal stay within more or less the same area for weeks or months before eventually moving to a new place? Surely it must have been feeding in the area, but how does it decide when it is time to leave? One of the central questions in behavioural ecology is whether animals have evolved many different kinds of behaviour, where each behavioural response is fine-tuned to a particular condition that the animals encounter in nature, or if a few simple mechanisms are sufficient to enable them to respond optimally in a wide range of conditions.

Porpoise in a pound net

The simulated harbour porpoise movements closely corresponded to those of satellite-tracked animals.

Porpoise release after tagging

The harbour porpoise (Phocoena phocoena) is an example of an animal species that displays very complex movement patterns. Porpoises often stay within relatively well-defined areas, or home ranges, where they presumably prey on various species of small fish before moving to new areas. In order to investigate whether a few different cognitive mechanisms could be sufficient to generate this complex behaviour, we developed a simulation model that included only two different kinds of behaviour. In the model the food was distributed in minute, scattered patches. Animals that had recently found plenty of food moved at random, much like cows that walk at their own pace in a field with lots of fresh green grass. Animals that had not been able to find food for some time became increasingly attracted to the patches where they had found food in the past. We let the animals’ ability to find their way back to previously visited food patches be governed by a spatial memory. It turned out that the combination of these two kinds of behaviour enabled home ranges to emerge, and when the animals’ memory about previously visited foraging sites decayed at a particular rate the model was able to produce movement patterns that closely resembled those observed for satellite-tracked porpoises in Danish waters. The right balance between the two kinds of behaviour also allowed animals to maximise their food intake. This suggests that it could be selectively advantageous for animals to base their decision on how to forage on a few, simple behavioural mechanisms.

Posted by: oikosasa | March 1, 2013

Plagiarism in Oikos?

We now check all submitted manuscripts for possible plagiarism using iThenticate.This means that all manuscripts are compared to more than 32 billion webpages, more than 34 million scholarly content items and more than 91 million news pages, books and magazines (and yes, these numbers are “plagiated” from iThenticate’s webpage…).

How similar are manuscripts generally to already published stuff? Most manuscripts show between 5 and 15% similarity.

And where is the limit for plagiarism? When a paper show more than 25-30% similarity with other published material, we do a thorough check for the similarities.

Reference lists, protocols in Methods and author adresslists may generate high similarities that are not really plagiarism. When high similarities are found in Results and Discussion, we act.

So it’s no use trying the copy and paste method for Oikos manuscripts…

Posted by: oikosasa | February 26, 2013

Top of the Pops

One of the most cited papers in Oikos, during 2011 (published 2009 and 2010) is “New perspectives for estimating body condition from mass/length data: the scaled mass index as an alternative method“, by J Peig and AJ Green.

Here, Jordi Peig gives a short summary of the paper and an explanation to it’s impact:

Jordi and Andy

Body condition (physical or nutritional status) is a widespread concept in the ecological literature. Although usually poorly defined, it encapsulates the animal’s health, quality and vigour, and hence its biological fitness. Scientists have used different approaches to estimate BC, but those based on morphometry and particularly on mass-length relationships have been adopted for routine use due to the ease of application and their ‘a priori’ conceptual simplicity. Briefly, morphometric indices attempt to quantify how heavy is an organism for a given body size, because the extra mass indicates more fat and protein reserves to overcome periods of food scarcity or high energy demand in general. However, larger animals will be inherently heavier, and vice versa, so the standardization of body size is the central challenge that underlies all morphometric methods, and is the subject of our paper. Many mathematical formulas and statistical methods have been proposed to standardise body size, yet there is still much debate among scientists as to the most suitable method.

The work published in Oikos has been popular partly because so many studies included attempts to establish the influence of body condition in population ecology. The idea of the paper was born in 2006 when distinct BC indices reported in the literature yielded opposite results when applied to my own data on small mammals. I found that those contradictory results were each scientifically plausible and arguable from an ecological viewpoint, hence the need to rethink the nature of these methods. After reading in and around the subject, including biostatistics, theoretical biology and epidemiology, I conceived the Scaled mass index. Because of the intrinsic tendency within sciences towards specialization, different disciplines have promoted and advocated their own methods (including the Body Mass Index used in medicine), and I searched for a common, unifying approach. With this complexity in mind, and the difficulty of publishing in this area for a PhD student (introducing alternative methods inevitably meets some scepticism and resistance) led me to seek collaboration with my co-author Andy Green, who had previously published in this field. From our first contact by email Andy was enthusiastic, and made substantial improvements to the manuscript. My original draft was prohibitively long for modern journals, and part of it went into a sister paper in Functional Ecology in 2010.

In the Oikos paper we attempt to explain the complexity of the BC issue from the fundamental viewpoint of allometric growth, and develop the Scaled Mass Index from that perspective. Amongst the papers that have cited our work, there are good independent examples of how our index outperforms previous methods. We can only hope that our future contributions on this topic become as successful as the Oikos’ paper.


Posted by: oikosasa | February 22, 2013

Mites hitch-hiking with bugs

Thumb’s out when the mite Spadiseius calyptrogynae needs to move to a new host plant. It can’t get their on it’s own, so it simply hitchhikes on bees, bats or beetles. Emanuel H. Fronhofer and co-workes have studied this in the new Early View paper “Picky hitch-hikers: vector choice leads to directed dispersal and fat-tailed kernels in a passively dispersing mite“. Here is Emanuel’s summary of the exciting study:

Tropical species diversity can be so high that while walking through a lowland rainforest it may be difficult to see two individuals of the same tree species. This phenomenon has fascinated generations of naturalists, but at the same time such high diversity represents a considerable challenge for any organism that, because of its biology, has to find another tree of a certain species to feed on, for example. How do specialized mutualists, predators or parasites manage to find their host(s)? This problem is especially relevant and critical for a lot of small, non-mobile species that occupy ephemeral habitats, such as small ponds, dung or, as in this study, flowers.

In this context, we have studied the dispersal strategies of a neotropical phoretic flower mite, that uses a number of different animal vectors – bats, beetles and bees – in order to hitch-hike from one host plant to the next. These mites (Spadiseius calyptrogynae) are specialized to their host plant, an understorey palm (Calyptrogyne ghiesbreghtiana), while the flower visitors and potential dispersal vectors are generalists.


The long distance disperser (Chasmodia collaris) on a male inflorescence of the palm Calyptrogyne ghiesbreghtiana (left). The detail (right) shows the phoretic mites (Spadiseius calyptrogynae) shortly after boarding their dispersal vector. Photo: E.A. Fronhofer.

Using a dual approach that combines field observations with experiments and individual-based modelling we find that our study species shows a highly developed capacity to discriminate between potential dispersal vectors based on chemical cues. These mites choose their dispersal vectors in order to optimize their dispersal kernel, i.e. the distribution of dispersal distances. The evolutionarily stable dispersal kernel is a mixed kernel resulting from short distance dispersal with bees (Trigona fulviventris) and rare long distance dispersal events with beetles (Chasmodia collaris). This results in a fat-tailed distribution of dispersal distances and additionally guarantees directed dispersal towards especially suitable habitat, as the short distance dispersers prefer young over old flowers.

Besides being an example of information use for making dispersal decisions, we show how passive dispersers may realize directed and long distance dispersal. Furthermore, our study highlights the benefits of combining field work and individual-based modelling or theoretical approaches in general.


Posted by: oikosasa | February 20, 2013

New populatin metrics for top-down-bottom up

Here is an interesting essay about measuring top-down-bottom-up effects, written by Leonard Polishchuk. He is also the first author of the Early View paper “How to measure top–down vs bottom–up effects: a new population metric and its calibration on Daphnia“, on which the essay is based.

Arguably, one of the saddest fallacies in ecology is the concept that «Everything is connected to everything else» (known as the first Barry Commoner law of ecology). The key assumption underlying this concept is that all interactions within the system are equally strong. Let’s examine which kind of science this assumption implies. Even in a modest system of 10 species the number of pair interactions between species amounts to 55 (including the effect of a species on itself), and to 5050 for a system of 100 species, leaving aside interactions with the abiotic environment. Such a large number is too big to study the interactions on a one-by-one basis, but probably too small to completely ignore their individuality. The latter is possible if the number of interacting entities is on the order of 1023, the Avogadro constant, but this will lead us to the realm of statistical physics rather than ecology. The Commoner law, if correct, would make our attempts to understand Nature almost hopeless, and turn ecology into hardly more than a casebook of idiosyncratic examples. Or, following Ernest Rutherford’s famous dichotomy, ecology would have been close to stamp collecting rather than hard science. (Rutherford actually said “physics” and was basically right, because physics is a role model for genuine science. But we do not think that “physics envy” can really motivate the ecologist.)


The picture is not all gloom, however. Rather than falling into despondency, one could quantify species interactions in order to see whether they are of the same strength or not. The actual problem, as it often happens, is therefore an operational one; it is about how to measure the things of interest. Let us focus our attention on trophic interactions, that is, on bottom-up and top-down effects. One way to assess them dates back to Justus von Liebig and consists of addition of biological nutrients to see which of them elicit a strong response from the pot plant, in terms of its growth, or from the planktonic algae in a water sample, in terms of primary production. These simple experiments, which in the era of ANOVA are called factorial-design experiments, immediately disprove the Commoner law. Liebig’s law of the minimum states that there is a single factor that produces the biggest response in a given species or a set of species with similar requirements, and thus affects them most strongly. Hence, not only the interactions are different in their strength but, under any given circumstances, there is only one that is most important. Clearly, the Liebig law makes a contrast with the Commoner law.

While the factorial-design experiment is a powerful and efficient tool to reduce the number of significant interactions and detect the strongest one, it has its shortcomings. The imposed shifts in food and/or predator abundance, while not completely arbitrary, may not reflect the current situation in the system. Often, for example, one of the treatments completely excludes predators, despite their presence in the environment. In his 2001 review, Mark Hunter sarcastically notes that if we were to completely exclude food, this would have inevitably revealed an “obvious and dramatic bottom-up effect”. Of course, nobody would act that way in regard to food but this reductio-ad-absurdum example shows a general problem: the manipulative (addition / removal) approach does take into account the actual (rather than imposed) dynamics observed in the system. The dynamics is a fundamental feature of natural systems (Pimm 1991), implying that one driving factor, e.g. food, may be quickly replaced by another, e.g. predation, in the course of time and space. The factorial-design experiment is not tuned to track these changes while a truly dynamic approach might be able to make it.


These considerations naturally bring us to the field of population dynamics. In the paper, we have focused on zooplankton, in particular Daphnia, a well-known model organism in ecology (Lampert 2011, see Figure), though we do believe that our approach is a general one and may not be limited to zooplankton. The population characteristic we are dealing with is birth rate. In part, this is because planktonologists can take advantage of the Edmondson-Paloheimo model for birth rate. Interestingly, birth rate as a response variable is somewhat similar to growth or production rates often taken as response variable in manipulation experiments, but our use of it is different. The Edmondson-Paloheimo model, being slightly modified (Polishchuk 1995), relates birth rate to fecundity and proportion of adults in the population. Fecundity is closely associated with food conditions and proportion of adults with size-selective predation, the latter being common in zooplankton. Thus, birth rate depends on both bottom-up and top-down effects, which is another reason why it is used here. To quantify the role of fecundity and hence bottom-up effects and that of proportion of adults and hence top-down effects in birth rate dynamics, we employ a mathematical approach called contribution analysis (Caswell 1989, Polishchuk 1995, 1999, Polishchuk and Vijverberg 2005, Hairston et al. 2005, Ellner et al. 2011). This provides us with the ratio of contributions of changes in the proportion of adults and fecundity to birth rate change taken as a measure of the relative strength of top-down vs. bottom-up effects.

We view the ratio of contributions as a kind of measuring instrument, something like a thermometer. The comparison of the ecological instrument to the physical one is, of course, a metaphor – primarily because ecological variables do not obey simple and general quantitative relations such as those used to construct physical instruments; an example is the relation describing the thermal expansion of the physical body, which underlies the functioning of the thermometer. But it is a useful metaphor, for it leads to the next task: calibrating the ratio of contributions as a tool to measure the strength of top-down vs. bottom-up effects. This calibration is based on microcosm and computer experiments, and constitutes a major part of the paper. The main experimental result is that the ratio of contributions allows one to distinguish a strong top-down effect from a strong bottom-up effect.

In the end, we would like to emphasize some points not mentioned in the paper. First, while our approach focuses on population dynamics and, as such, is intended to avoid inappropriate averaging (used, though implicitly, in manipulative experiments), some time-averaging seems necessary. The ratio of contributions is found to be sufficiently robust only when applied to a set of successive sampling intervals rather than an individual interval. (This set covers the second part of the experiments where top-down and bottom-up effects appeared in full strength; see Online Appendix 3 of the paper.) In our experiments, this set was identified by means of ANOVA, the procedure that will not apply to field populations due to lack of “replicate populations”. Hence, we need to understand how to recognize, in natural populations, a set of intervals over which the ratio of contributions remains roughly constant. This will open the way to the use of this approach for natural Daphnia (and other zooplankton) populations.

Second, the Edmondson-Paloheimo model, when appropriately modified, has the potential to estimate birth rate in animals other than Daphnia, such as mammals. If applied to a wider range of organisms, this approach may be a useful supplement to conventional Liebig-style factorial-design experiments.

Posted by: oikosasa | February 18, 2013

Hiding in the litter from the beasty ants

In the new Early View paper “Non-trophic effects of litter reduce ant predation and determine caterpillar survival and distribution”, Richard Karban and co-workers have studied the importance of litter for caterpillars hiding from ants in a hetergenous landscape. Here is Richard’s lay summery of the paper:


It is well established that trophic interactions can influence the spatial distribution and abundance of organisms.  What is less well understood is how these interactions vary across space.  In this study, we conducted several observational surveys and manipulative field experiments to examine the role of predators as drivers of caterpillar abundance and distribution across a heterogeneous landscape composed of three predominant habitat types, marsh, coastal grassland, and dune.  Unexpectedly, ants were found to readily prey upon early instar caterpillars.  The intensity of predation varied across habitat types such that caterpillars in marsh habitat had a higher probability of survival than those in drier, upland habitat. Marsh habitat in our study system is characterized by think leaf litter, while less leaf litter is associated with drier habitat.  We hypothesized that habitat substrate complexity may moderate caterpillar predation by ants. This hypothesis was supported by two findings: ant recruitment to baits decreased with litter depth and litter protected caterpillars when ants were present but not when ants were experimentally excluded. Our results show that litter confers a survival advantage to caterpillars by providing habitat, a non-trophic mechanism. In contrast to trophic effects, the importance of spatiotemporal variation of non-trophic effects in mediating species interactions has been underappreciated by many ecologists.


Posted by: oikosasa | February 15, 2013

Cascading effects of fish migration

How the anadromous fish alewife affect the whole food-web in it’s ecosystem is studied by Jerome J. Weis and David M. Post in their new Early View paper “Intraspecific variation in a predator drives cascading variation in primary producer community composition”. Below is Jerome’s presentation of the paper:

We know that predation can have a strong influence on the richness, biomass, and composition of prey communities.  We also know that these effects can cascade down a food web to lower trophic levels, including primary producers.  Often, when we design studies to ask how these top-down effects of predators influence lower trophic levels, we focus either on differing densities of a single predator species, or on differences among multiple species.  However, in some cases, variation within a predator species can be an important component of these top-down effects.

YOY AlewifeMesocosms 2

In coastal New England lakes, a species of zooplanktivorous fish, alewife, has a strong influence on zooplankton biomass, diversity, and composition.  Among lakes that support alewife, populations show one of two distinct life histories, an anadromous life history, where ocean residing adults spawn in coastal lakes and young-of-the-year alewife have a substantial impact on zooplankton communities from approximately June until November, and a landlocked life history, where alewife populations are isolated from the ocean and are present through the year.  Differences in the behavior, morphology, and seasonal timing between anadromous and landlocked alewife drive distinct differences in their zooplankton prey communities across the landscape.

In this study we tested the hypothesis that alewife presence and life history will have cascading top-down impacts on phytoplankton density and community composition. We analyzed phytoplankton communities from a mesocosm experiment that manipulated the presence and life history form of alewife and observed lower zooplankton biomass density, average size, and species richness in the anadromous treatment than the landlocked and no-fish treatments.

Mesocosms 1Phytoplankton

We observed a statistically significant shift in phytoplankton community composition among treatments that was consistent with lower zooplankton densities in the anadromous alewife treatment.  The biovolume density of two common single-celled phytoplankton genera, Chlamydomonas and Gymnodinium, was significantly higher in the anadromous treatment than the landlocked and no-fish treatments.  Both of these genera are considered vulnerable to herbivory by zooplankton.  However, these differences in community composition did not result in statistically significant differences in overall phytoplankton biovolume density nor richness among treatments, suggesting that the cascading effect of alewife was relatively small in this study.

Posted by: oikosasa | February 13, 2013

Modelling species interactions

A model to quantify species interactions is proposed in the new Early View paper “Costs, benefits, and loss of vertically transmitted symbionts affect host population dynamics” by Kelsey M. Yule, Tom E.X. Miller and Jennifer A. Rudgers. Below is Kelsey’s background story to the study:

How do we quantify the relationship between two species? When individuals of the two species interact at many points throughout their lifetime, the answer is not as simple as we sometimes assume.  The effect of the interaction at different points in the species’ life history may not affect fitness in the same way. Take, for example, an insect pollinator that greatly increases the reproductive success of its plant partner. We might consider this a classic example of a mutualism, as the presence of the pollinator allows the plant to produce more seeds and the presence of the plant allows the pollinator to produce more eggs.  However, that same pollinator may lay those eggs directly onto the plant, which later suffers significant herbivory damage from the larvae. So, which plant produces more offspring: the one that interacts with that particular pollinator or the one that doesn’t? Without following the plants’ growth, reproduction and survival throughout their lifetimes, it’s difficult to say. Even humans harbor many symbionts of which the varying positive and negative effects are only recently beginning to be understood and debated.  This tension between cooperation and conflict is not uncommon in many of the systems we traditionally call mutualisms or parasitisms. In our paper, we argue that a snapshot at one point in the life history is not sufficient for understanding the population-level effects or evolutionary significance of any interspecific interaction.

Fungal endophytes that produce herbivore-deterring alkaloids are generally considered clear mutualistic partners of their grass hosts in agronomic systems.  Yet, confusion and debate over their role in native systems has arisen due to some documented costs, notably reduction in host survival.  Theory suggests that when these endophytes are vertically transmitted, harming their hosts should doom them to extinction, as the endophytes can only increase their own reproduction by increasing their hosts’ reproduction.  Yet, vertically transmitted endophytes are often present at high frequencies in native systems, despite transmission rates that can be well under 100%. Therefore, we wondered whether an approach that could integrate the effect of endophytes across the entire life history of the host could shed some light on this problem.

To do this, we developed a new modeling approach in which we could structure a native grass host’s population both continuously by size and discretely by the presence or absence of endophyte symbionts.  With our integral projection model (IPM) megamatrix, which we parameterized with experimental field data, we were able to show that endophyte symbiosis provided a net benefit to its host by increasing population growth. Indeed, we saw costs to host survival that were outweighed by boosts to growth and reproduction.


More surprisingly, we saw some patterns that we did not expect given previous theory. Early life history stages, like germination and seedling establishment, were critically important for determining the locations of transmission rate thresholds below which these beneficial symbionts go extinct.  For example, if seedlings are able to survive to adulthood 2% of the time, endophytes will not be able to persist if endophyte symbiotic adults produce endophyte symbiotic seeds, as opposed to endophtye-free seeds, less than 50% of the time. However, if seedlings establish 3% of the time, endophyte persistence requires a transmission rate of more than about 75%.  This complex interaction between early life history and vertical transmission arises because higher seedling establishment leads to a greater proportion of the population being made up with seedlings, which will be dominated by endophyte-free plants at low transmission rates. This result also highlights the need for a greater understanding of the mechanisms behind variation in endophyte transmission.

We believe that the modeling approach we developed will be broadly applicable to understanding how species interactions, especially those involving vertically transmitted symbionts, influence populations.  For myself, this research, which I began as an undergraduate, is influencing my thoughts on species interactions as I start my graduate career at the University of Arizona.  In the future, I hope to continue integrating models with empirical data. I believe that doing so is a  particularly powerful way to improve our understanding of relationships in nature that so often slide on the continuum between mutualism and parasitism.

Posted by: oikosasa | February 12, 2013

To join the party or not…?

Did you believe that hermite crabs were always seeking lonelyness? Oh, now, partytime might attract the hermits as well! Read more in the new Early View paper “Eavesdropping foragers use level of collective commotion as public information to target high quality patches” by Mark Laidre. Here is Mark’s own short verison of the paper:


Many people like a party that’s pumping and jostling at just the right amount. Too little commotion and it’s just not attractive. The same seems to hold for terrestrial hermit crabs, which are highly social animals that frequently join aggregations of conspecifics to acquire valuable resources like food or shells. We conducted an experiment to determine what level of commotion from an aggregation would be most attractive to crabs that were eavesdropping outside the aggregation and deciding whether or not to join. The experiment involved creating the equivalent of a puppet show for hermit crabs, with several plugged shells being jiggled at the end of fishing line to simulate different levels of jostling by an aggregation. The jostling of these sham aggregations represented the sort of wild commotion and fighting that goes on when hermit crabs are competing with one another naturally. Indeed, when hermit crabs are contesting highly-quality food resources or when they are in the process of evicting another individual from its shell, their aggregations exhibit especially high levels of natural jostling. In our experiment, we found that eavesdropping hermit crabs were most attracted to the sham aggregations that were jostled at higher rather than lower levels, suggesting that the crabs were using the raucous public commotion as a reliable cue to the presence of valuable resources that were worth competing over. Our experiments provide the first evidence that animals use the behavioral by-products of collectives as a way to increase their own personal foraging efficiency.

Posted by: oikosasa | February 7, 2013

Environmental pollution goes theoretical ecology

Pollution issues meet complex food-web modelling and theoretical ecology in the Early View paper “The more polluted the environment, the more important biodiversity is for food web stability”, by Leslie Garay-Narvaez, Matias Arim, José D. Flores and Rodrigo Ramos-Jiliberto.

RodrigoHere’s the background story to the study, written by Rodrigo Ramos-Jiliberto:

I was the advisor (together with M. Arim) of Leslie Garay-Narváez, who recently obtained her PhD degree at the University of Chile. This article is the first chapter of her PhD dissertation. When we began to think about possible alternatives for her thesis work, Leslie decided to combine a theoretical approach for studying the dynamics of food webs, with questions related to the effect of human disturbances, particularly pollution. Our desire was to connect very abstract work, based on mathematical modeling and complex networks, with practical needs of social interest. Thus, we decided to go in the direction of revising or perhaps reformulating some key issues of ecological theory, which had been building (explicitly or implicitly) with a pristine world in mind, but considering a polluted world. We envisioned developing some sort of “applied theoretical ecology of polluted complex systems”. In this article we show how the complexity-stability relationship is affected by pollution. Two other papers are in the pipeline.

LeslieAs a result of Leslie’s work, our institution, the National Center for Environment (CENMA), appreciated the importance of theoretical ecology, and many members of our academic community agreed in that applied questions are affordable from a sound, theoretical perspective. After that, three months ago, Leslie became a happy mother of a baby and obtained a 3-year postdoc fellowship at the University of Chile. Indeed in developing countries like ours, science is a fine form of living, and theoretical ecology even better !

Posted by: oikosasa | February 4, 2013

Pasture – red kangaroo – dingo interactions

Read David Choquenot’s and David M. Forsyth’s new Early View paper “Exploitation ecosystems and trophic cascades in non-equilibrium systems: pasture – red kangaroo – dingo interactions in arid Australia” to learn more!

Here’s Dave’s background story to the study:

Fig1_Dave Forsyth at Kinchega National Park

This article had a long gestation. The seeds were sown in 2000, when two influential articles were published in The American Naturalist on the inter-related topics of trophic cascades (Schmitz et al. 2000 Am. Nat. 155, 141) and the Exploitation Ecosystems Hypothesis (EEH; Oksanen and Oksanen 2000 Am. Nat. 155, 703). After reading these articles we discussed the idea of adding the dingo (the top-order predator in mainland Australia) to Graeme Caughley’s two-link rainfall – pasture – red kangaroo model (Caughley & Gunn 1993 Oikos 67, 47), to test whether an empirically derived model could recreate EEH predictions and generate trophic cascades. In Caughley’s system, which was based on data collected in Kinchega National Park (western NSW; Image 1), prevailing productivity is tightly linked to rainfall through its effect on pasture growth and dieback. However, rainfall in this ecosystem is highly stochastic between seasons and years. Over the subsequent ten years we worked sporadically to test whether this system could produce dynamics consistent with the EEH and trophic cascades.

The model did reproduce the three zones predicted by the EEH, but a surprising outcome was the discovery of an additional zone at productivities above which the maximum densities of the dingo was achieved. The additional zone, in which kangaroo densities increased and pasture biomass declined due to the re-engagement of the kangaroo-pasture feedback loop, occurred because dingo densities are believed to be socially regulated (via dominant female infanticide): if dingo densities are instead constrained wholly by the availability of kangaroos then that zone disappears, kangaroos become less abundant and pasture biomass more abundant.


Increasing stochasticity in seasonal rainfall had sometimes counter-intuitive effects on model outcomes. High levels of stochasticty led to more frequent extinction of dingoes from the system, resulting in the re-engagement of the kangaroo-pasture feedback loops. Hence, increasing stochasticity led to increased attenuation in this system.

Roger Pech (Landcare Research, New Zealand) thoughtfully suggested that we use the normalized difference (rather than the absolute difference) of the log-response ratios to evaluate attenuation in this system. Roger’s suggestion will be appropriate to other studies assessing attenuation in trophic cascades.

Several journal reviewers also suggested that we assess the effects of potential diet switching by dingoes from kangaroos to reptiles, as has been observed in some areas of arid Australia. We found that prey switching by dingoes to reptiles weakened trophic cascades.

The role of the dingo as a trophic regulator has been the subject of much recent debate, with some scientists calling for culling to cease and reintroductions to be made in areas where it has been extirpated. The rationale for returning dingoes to previous densities in parts of their range focuses primarily on their potential to reduce the abundance of introduced red foxes and feral cats. However, our study suggests that additional benefits may occur through regulation of large kangaroo abundance, and the associated release of vegetation from grazing pressure. Depending on the degree to which the diversity of each trophic level is maintained by consumption-mediated co-existence, these changes may have flow on implications for amongst herbivores and vegetation biodiversity in these ecosystems.

Our study has generated testable predictions about interactions between top-order carnivores, their prey, and vegetation across productivity gradients. These predictions are obviously highly testable in Australia where dingo management is widespread. However, the generality of the predictions could also be tested in entirely different predator-driven ecosystems.

Posted by: oikosasa | February 1, 2013

The elephant in the room


What makes invasive species invasive? Find some of the answers in Rafael Zennis and Martin Nunez paper “The elephant in the room: the role of failed invasions in understanding invasion biology”  now on Early View.

Here, Martin Nunez gives a short background:

Invasive species grow bigger, reproduce earlier and more often, and spread faster than other species, right? Well, sometimes yes, but not always. Many known invasive species have populations introduced in areas where they do not naturalize or invade after arrival. As it turns out, only invasive populations exist in nature. In this study, we reviewed the literature on invasions and found that failures are the most numerous and often ignored part of the biological invasion process. We learned that very few people are interested in introduced populations that do not thrive in the new environment. There are many anecdotal reports on failures, but really few studies on why these populations fail. We also found that different mechanisms may be causing failures vs. successes, but more research is needed to shed light on this. Based on these findings, we show and discuss research areas where it may be key to incorporate more info on failures to avoid an important bias.


Maritine pines (Pinus pinaster) are invasive in many parts of the southern hemisphere, but in Rio Negro, Brazil, experimental plantations died out 18 years after planting leaving no trace of its past presence in the area, now colonized by exotic eucalyptus and native araucaria pines.

We focused our study on reviewing cases of species that are invasive somewhere, but that fail to invade in other areas, habitats or time periods. We did this because these situations can provide useful information on the particular mechanism of invasion (e.g., what is different between areas where the species invade and where the species does not invade?). We avoided studying species that never invaded, which might provide little information about other invasive species.  Finally, we put caution in the use of the term “invasive” to indicate an intrinsic species-level trait because even some of the most aggressive invaders are reportedly unable to colonize some area. This does not change, however, the fact that when introduced organisms do invade, they may cause considerable changes in community and ecosystem dynamics.

Posted by: oikosasa | January 31, 2013

Waste to hurry

Do animals spend too much energy on just being? Read Bas Kooijman’s new Early View paper “Waste to hurry: dynamic energy budgets explain the need of wasting to fully exploit blooming resources” to find out! Here, Bas gives you the background to the study:

Many years ago, I did a very simple experiment, which results puzzled me for a long time. Take 6 beakers, fill them with water, add 5 daphnids each, and feed them with algae daily. The beakers got 6, 12, 30, 60, 120 and 240 million cells per day, respectively, for 24 days. Except for the highest feeding level, all daphnid populations settled to constant numbers per beaker in this period and the numbers are directly proportional to the feeding levels. To convince myself that it really is the feeding level that controls the numbers, I gave all beakers 30 million cells per day after 24 days and indeed all numbers converged to that level. From this we learn that a 2.8 mm daphnid needs 6 algal cells per second at 20°C and they cannot grow or reproduce with this intake and all need it for maintenance only. With plenty of food they can become over 4 mm and produce some 20 young per day. It turns out that they have a specific maintenance cost that is two orders of magnitude bigger than is typical for animals. My problem was to understand why.


Some two years ago, I started the add_my_pet collection of data on animal energetics, and fitted the standard Dynamic Energy Budget model to each species. These data and the model cover all aspects of energy and mass balances during the full life cycle of individuals, including the embryo stage. The collection has representative of most larger animal phyla, ranging from 2.4e-8 g hairy-backs to  1.6e8 g blue whales. I developed this model to separate overhead costs of assimilation, growth and reproduction from maintenance. Because of the presence of reserve as quantifier for metabolic memory, this task is less easy than is generally recognized. In fact, it requires a whole new view on the relationships between respiration, metabolic rate and maintenance. With help of many enthousiastic people, the add_my_pet collection grew till 165 species at present.

By comparing extremes in specific maintenance costs I found the explanation for the very high maintenance costs of daphnids and for why it took me that long to see it. It is namely completely counter-intuitive: animals need to waste resources to boost their growth and reproduction. Within the context of the Dynamic Energy Budget theory, it is completely logical and easy to understand, the only problem is to recognise it. It has been sitting right before me for 30 years and I didn’t see it. Intuition is not always a good advisor.

Posted by: oikosasa | January 30, 2013

Editor’s choice Febuary

DriesEditor in Chief Prof. Dries Bonte introduces the two Editor’s choice papers in the February Issue: (Note that Editor’s choice papers are Open Access)

For the February issue of Oikos, we decided to highlight Sorte’s forum paper on the importance of flow direction and limitation to redistribution for the persistence of species in the light of climate change, and the contribution of Stier et al., demonstrating the use of model-based approaches to study functional predator-prey responses within a community context. These contributions were chosen according to our motto of synthesising ecology.

Sorte (2013) emphases the role of directional flows of wind or water currents as an important factor limiting species’ distributions, especially when equilibrium conditions become disrupted by human interference. There is a consensus that adaptation or tolerance may not be sufficient for many species to persist under conditions of climate change, and that dispersal is essential to keep track with the shifting climate window. In cases of actively moving organisms, such movements can be expected to be informed and at least partly in the direction of the shifting window. Passively dispersing organisms, being either wind dispersed plants, rafting arthropods or planktonic stages of many marine vertebrates and invertebrates are expected to face constrained movements due to their dependency on flow directions. Such asymmetric air and water flows need to be considered when assessing the vulnerability of populations and species to climate change. Cascade Sorte provides a synthesis on how the interplay between directional flows and life histories may limit species’ distributions and their persistence under climate change. The review comes up with clear predictions that may help ecologists to detect the set of passively dispersing species at risk, but equally provides clear considerations for future research.

Adrian Stier and colleagues provide a novel analytical tool for analysing predator foraging behaviour and offer insight into the processes driving the dynamics of coral reef fish. While group benefits are well documented from a single-species point of view, we lack insights on how such group benefits change according to the community context. In their study, the authors use a shoaling coral reef fish as a model species to test how prey group benefits change according to group size, the presence of competing predators and alternative prey. They use an original approach by quantifying mortality rates as perceived from the predator’s perspective, so by quantifying changes in the predator’s functional response. Their sets of experiments confirm group size advantages by reduced predation risks, but these benefits decrease in the presence of alternative prey species. While there is already quite some literature demonstrating such a community context of predator-prey interactions, the applied model-based approach allowed for testing several alternative hypotheses of mechanisms leading to variation in functional responses.

Posted by: oikosasa | January 29, 2013

Surf and Turf 2: Snorkeling with wildebeest

We have now come to the second Surf and turf paper in Oikos february issue. I let Deron Burkepile introduce you to his study “Comparing aquatic and terrestrial grazing ecosystems: is the grass really greener?”


At a big ecology meeting, you can often tell what people study by how they dress – the marine ecologists (Hawaiian shirts, flip flops), the terrestrial ecologists (Chacos or Tevas, Carharts). As an ecologist, the communities and ecosystems you study often define you – forest ecologist, intertidal ecologist, benthic ecologist. Like our current series of reviews and commentaries in Oikos trying to bridge the gaps among terrestrial, marine, and freshwater ecology, we often compare and contrast the different patterns and process in our different ecosystems via reviews and our meta-analyses. We search for common patterns and themes and build testable hypotheses, even theories. Yet, many of us don’t have research experience outside of a couple of closely related ecosystems. For many of us, branching out to a new ecosystem means including tropical forests into our research program on temperate forests. But, I would argue that we could all be better ecologists, if we truly had diverse research experiences on our ecological resumes, and the field would be better for it.

Having had a diversity of research experience, I feel like I am one of the lucky ones. I’ve spent more than a decade studying coral reefs, even lived underwater for a total of twenty days in the Aquarius, an undersea research station off of Key Largo, Florida to study herbivorous fishes (parrotfishes and surgeonfishes) and their importance to reef ecosystems. But, I also got to spend two years living in a tent in Kruger National Park in South Africa (periodically having to put my computer in the refrigerator to keep it from overheating in the 40°C+ heat). Instead of parrotfish and surgeonfish, I was studying elephants, wildebeest, and impala and how these different herbivores structured savanna ecosystems. While the beasts were different, the ecological processes were not. I like to think I’m the only ecologist who has gotten to live and work both in the bush in Africa and also underwater (if you know otherwise, please don’t burst my bubble).

How did I get from coral reefs to African savannas and back? It all started with reading broadly. While studying for my qualifying exams as a graduate student in coral reef ecology, I came across the classic papers on the Serengeti by Sam McNaughton and the book Serengeti: Dynamics of an Ecosystem by Sinclair and Norton-Griffiths. I was enthralled reading about wildebeest migrations, the dynamics of multiple large predators, and the overwhelming impact of herbivores on the landscape. As I was devouring the coral reef ecology literature, I couldn’t help thinking how similar coral reefs and African savannas actually were. Instead of herds of wildebeest there were schools of parrotfish. Instead of roving impala, there were marauding urchins. Regardless of whether the system was wet or dry, big, diverse groups of herbivores ran the show. I was fixated on how cool it would be to test similar hypotheses about how diverse groups of herbivores impact community structure and ecosystem function in two structurally different, but functionally similar ecosystems.

After convincing my future post-doc advisor, terrestrial ecologist Melinda Smith, that it would be a good idea to let a marine ecologist who had never even been to the African continent to go live in a tent in South Africa and study ungulates, it was mostly downhill from there. Of course I had to learn a brand new ecosystem (dry vs. wet), a new set of taxonomy (grasses vs. seaweeds), a new set of dangers (lions vs. sharks), get used to new field methods (see picture as exhibit A), and learn a new set of literature (fun, and probably the most challenging part). There are clearly concepts that don’t cross these ecosystem boundaries. The effects of drought and water stress are extremely important at our sites in the savanna – on a coral reef, not so much of a problem. But after six years of working in both African and North American savannas while also continuing my work in reef systems (yes I have a lot of frequent flyer miles), I’ve been able to build a much more nuanced and thorough understanding of how herbivores shape ecosystems and of the drivers that determine herbivory.

So I encourage ecologists at all levels (especially ones early in their careers) not just to read broadly but to research broadly. Start a collaboration with someone in a very different ecosystem than your primary research. If you work in forests, go talk to someone about kelps. It will push your intellectual boundaries and stimulate more ideas to tackle in your primary research area. Every aspect of your career will likely benefit, from your lectures to your journal reviews to your grants.

I remember in my first few months in South Africa walking through an area of savanna where an African buffalo herd had been the day before. The soils were churned, the small shrubs mangled, the grasses gnawed. But what I remember most was the amount of dung. Buffalo flops everywhere. I distinctly remember thinking how important these big herds must be for moving nutrients around the landscape and impacting primary production. That same scene came to mind a couple of years ago while diving on a coral reef watching big schools of fish congregate around corals. That same thought then popped into my head – how important these fish must be for moving nutrients around within this landscape. So, now one of my lab’s main areas of research is the impact of fish-derived nutrients on coral reef community structure and ecosystem function. My blended heritage of marine and terrestrial ecology will, hopefully, continue to help me unravel the connections and common themes between wet and dry ecosystems. Even now, when I am following a parrotfish around the reef documenting its feeding behavior, I can’t help but think “What would a rhino be doing?”

Posted by: chrislortie | January 25, 2013

The future of publishing for ecology & evolutionary biology

An NCEAS working group examining the future of publishing in ecology and evolutionary biology ( would like to solicit your input. Our goal is to establish a baseline of your opinions on the current state of scholarly communication for our field so as to highlight potential gaps and improvements. The survey includes the opportunity to provide feedback on the value of Twitter, blogging, social networking, and other online outlets as it relates to publications.

The survey will take approximately 7-10 minutes.

Posted by: oikosasa | January 25, 2013

Surf and Turf 1

Yesterday, Randi Rotjan and Josh Idjadi introduced us to the Surf and Turf concept. Today, Howard V. Cornell gives a short background to his and Susan P. Harrison’s Surf and Turf paper “Regional effects as important determinants of local diversity in both marine and terrestrial systems”:

When Josh Idjadi and Randi Rotjan organized the Surf and Turf Symposium at the 2009 meeting of the Ecological Society of America, it was immediately clear that they had identified an important problem. Marine and terrestrial ecologists do not always follow each others’ work, and as a result, there is not enough cross-fertilization of ideas derived from the study of these two realms. When Josh and Randi invited Susan Harrison and me to participate in the symposium, it forced us to think hard about how large-scale biogeographic  and evolutionary processes affect the species diversity in marine vs. terrestrial communities. Because of differences in dispersal between atmospheric and aquatic media, the ease of identifying marine vs. terrestrial species pools, and the historical development of marine and terrestrial community ecology, marine ecologists have placed more emphasis on the importance of large-scale effects on community structure than terrestrial ecologists. Nevertheless, it became clear to us upon reflection that large-scale processes are important in both realms but such processes are studied in different ways. We were grateful for the opportunity afforded by the symposium to look at this issue more deeply and as a result, have come to a clearer understanding of the general importance of examining different spatial scales when trying to understand ecological patterns. Below is a short summary of our paper.

s&t1bs&t1Terry Hughes

One apparent difference between marine and terrestrial ecology is that the influence of regional processes on local populations and communities is better established in the marine literature. We examine three potential explanations: 1) influential early studies emphasized local interactions in terrestrial communities and regional dispersal in marine communities. 2) regional-scale processes are actually more important in marine than in terrestrial communities. 3) recruitment from a regional species pool is easier to study in marine than terrestrial communities. We conclude that these are interrelated, but that the second and especially the third explanations are more important than the first. We also conclude that in both marine and terrestrial systems, there are ways to improve our understanding of regional influences on local community diversity. In particular, we advocate examining local vs. regional diversity relationships at localities within environmentally similar regions that differ in their diversity either because of their sizes or their varying degrees of isolation from a species source.


Figure: Scenarios for propagule supply in marine and terrestrial systems. (a) In marine systems, habitats are immersed in a homogeneous surrounding medium containing propagules of many species with few dispersal barriers, many of which pass through the fitness filter and are able to recruit to the habitat. (b) In terrestrial systems, topography and environmental heterogeneity erect larger dispersal and fitness barriers to arriving propagules and ‘seed banks’, confound arriving propagules with those already present in the habitat.

Posted by: oikosasa | January 24, 2013

Surf and Turf in Oikos Feb 2013

Check out the Surf & Turf papers in the February Issue! For an introduction to the concept, I leave the word to our Surf and Turf editors Josh Idjadi and Randi Rotjan. Their introductory paper in the February Issue is found here. Presentations of the actual papers are to come on this blog the following days!


It is an interesting time to be a scientist. We have access to more research tools and information than ever before, including literature access. With that access comes great opportunity: data mining, meta-analysis, global comparisons and insights, and cross-disciplinary and cross-system inspiration. However, this tremendous level of access also opens up the conversation about responsibility: are we responsible for reading that huge literature? The answer is, by necessity, “of course not”.  But like everything in science and in life, this is not a black and white issue. Among the many shades of gray are whether or not you have the responsibility to read everything in your field (traditionally, “yes”), but defining ‘your field’ is ever-harder. Is your field defined by the organism you work on? By the ecosystem you work in? By the methodology you use? By the types of questions you try to answer? The answer is “all of the above, depending on the situation”. Practically, however, it would be impossible to read and absorb information on all of these levels, in real time, all of the time. Not only do we have more access to information, but there is more information! More scientists, more journals, more articles, and more communication mediums (including blogs, like this one). In reality, we all simply do the best we can, all-the-while recognizing the importance of deep and wide reading to good scholarship.

Recently, in a rare moment of quiet and clarity, we realized that our worlds had become very “marine”. Though we both graduated from more traditional and cross-system biology departments and considered ourselves ecologists, in reality, we were working in marine systems, attending marine conferences, and immersed in marine literature. We missed being part of the general biological scene, and we wanted to engage in the scholarly exercise of thinking about some of our research questions from the perspective of a different field.  “Surf and Turf” emerged as a concept – not to wholly solve the problem – but as one part of the solution to service cross-systems cravings in a way that would be relatively short, with a reasonable time investment, and would engage collaborators in a meaningful discourse without diluting point-of-view by trying to reach consensus in a single document. We thought an effective format for this concept might be a main piece on a topic by a system-specific author, with short responses written by other system-specific authors. In this multi-paper-per-topic dialogue, the goal was to achieve breadth without compromising depth in a format that didn’t swamp an individual author by forcing an all-systems literature review, and in a way that didn’t swamp the already overwhelmed reader who is forever trying to keep up with their own field (however it may be defined).

Our authors found both agreement and debate in the 2 topics highlighted by Oikos (regional determinants of diversity, and grazing ecology), and we hope this virtual issue showcases these 2 topics as proof-of-concept examples for future Surf and Turf endeavors. In the process of putting this virtual issue together, we engaged with a number of other authors who are pursuing other venues for several additional topics. Oikos was a wonderful place to launch this concept – and we are now hoping that other journals and authors will embrace it. Still immersed in our system-specific questions, we both value and recognize the importance of cross-systems ecology as one of the key drivers of synthesis. This will not be our last attempt at cross-systems thinking, and we encourage you to do the same.  And at the least, and in this cluttered world of fast-flowing literature: thank you for reading.

-Randi Rotjan & Josh Idjadi

Posted by: oikosasa | January 23, 2013

Is competition less common i harsh environments?

What do animals actually do in poor environments? Compete more or facilitate for each other? Isabel Barrio and her co-workers studied this in herbivores in the harsh alpine tundra, resulting in teh new Early View paper: Extending the stress-gradient hypothesis – is competition among animals less common in harsh environments? Here’s Isabel’s own background story to the study:


Many summers in the alpine tundra have inspired our study.  Alpine environments are strongly seasonal and are characterized by harsh environmental conditions, but they can host a surprisingly large numbers of herbivores.  Annual net primary productivity in alpine ecosystems is generally low, so negative interactions (i.e. competition for resources) are usually expected to dominate among herbivores.  However, the stress gradient hypothesis (SGH) developed by plant ecologists leads to the opposite prediction; namely, that in stressful environments, positive interactions (i.e. facilitation) would be the most common type of interaction.  But, are plants and animals so different in this respect?  Although facilitation among animals has been described in some highly productive ecosystems, such as tropical savannas, no theoretical framework exists that relates the balance between positive and negative interactions along environmental gradients.  In our paper “Extending the stress-gradient hypothesis – is competition among animals less common in harsh environments?” we evaluate how the stress-gradient hypothesis might apply to terrestrial herbivores.  


We considered  alpine herbivores for developing our framework, because most examples of the SGH come from alpine plant communities.  According to the SGH, and given that stress for herbivorous animals in these environments can be equated to inverse productivity gradients, we wondered if positive interactions would prevail in alpine environments because of their low productivity.  We reviewed the available examples on interactions among alpine herbivores and found very few experimental studies on this topic.  Interestingly, they were biased towards reporting on significant competitive interactions.  Despite this bias, we found no evidence of competition being the dominant interaction type in low productivity alpine environments, which directly challenges the dominant view among animal ecologists.  Although we did not find strong support for the SGH either, we argue that specifically designed experiments can help investigate the applicability of this framework to terrestrial vertebrates.  Extending the SGH through clear predictions can provide a solid starting point for understanding the role of positive and negative interactions in structuring terrestrial animal communities.

sheep marmot

Posted by: oikosasa | January 21, 2013

Editor’s choice January

From January 2013 our Editor’s in Chief select two papers in each issue as Editor’s Choice. Those papers are Open Access, and the complete January Issue is OA! Here, Dries Bonte explains why they chose the following for the January issue. Read more here about News in Oikos 2013.

DriesThe following papers Pattern Detection in Null Model Analysis’ (Werner Ulrich and Nicholas J. Gotelli) and How does the invasive/native nature of species influence tadpoles’ plastic responses to predators’ (Eudald Pujol-Buxó, Olatz San Sebastián, Núria Garriga and Gustavo A. Llorente)were selected as the first editor’s choice papers for 2013.

We selected these papers for two different reasons, thereby demonstrating the different pathways by which ecologists can create synthesis in their own field of expertise. The work by Pujol-Buxó considered the importance of phenotypic plasticity in both functional morphology and behaviour in a set of invasive and native prey and predators. The work brings synthesis by merging concepts of behavioural ecology, developmental plasticity and invasion ecology and provides a mechanistic understanding of invasions in a well selected set of species (interactions).  It is true that the ecological impacts of invasions are becoming well understood, often in the sense of impact on population and species dynamics of native species. However, since all changes in ecology should ultimately result in altered selection pressures and back, more effort is needed to understand eco-evolutionary dynamics of species invasions, both in the invasive and native species. This field becomes nowadays overwhelmed with theory and empirical work is clearly lagging behind, so contributions like this are essential as critical tests of the developed theory.

The second contributions Ulrich and Gotelli emphasises on the proper use of different metrics to identify distinctive patterns in species x site presence-absence matrices. These approaches are important for understanding metacommunity organisation. Because the behaviour of different metrics is often correlated, it proved to be difficult to distinguish different patterns. Therefore, Ulrich & Gotelli created synthesis by testing the performance of a suite of null models and metrics that have been proposed to measure patterns of segregation, aggregation, nestedness, coherence, and species turnover. While there is no need to provide more detail here, they concluded that sources of non-randomness are best assessed by using different combinations of metrics. As such the paper is a natural and logic continuation of their previously published and highly valued consumer’s guide to nestedness analysis. We are sure that this contribution will receive the same attention and use in future community ecology.


Posted by: oikosasa | January 18, 2013


It’s always fun to read all submitted manuscripts. Especially when explanations are like this:

bakerypostdocI’m very happy that it doesn’t happen too often!

This one was actually copied from  #overlyhonestmethods

Have a great weekend everyone!

Posted by: oikosasa | January 17, 2013

Understanding wood decomposition

How do wood decomposition relate to other traits in the tree? Answered by Benjamin G. Jackson and co-workers in the Early View paper “Are functional traits and litter decomposability coordinated across leaves, twigs, and wood? A test using temperate rainforest tree species”. Here’s Benjamin’s short summary and his pedagogic figure showing the results:

Dead wood represents an important pool of carbon and nutrients entering the decomposer subsystem in forested ecosystems. However, our understanding the factors regulating wood decomposition remain poorly characterized. In our study we ask two main questions:

  1. Do tree species with leaves that decompose rapidly also have wood that decomposes rapidly?
  2. Do the same functional traits that control leaf litter decomposition control the decomposition of wood?

We addressed these questions by comparing how traits and litter decomposition vary across 27 co-occurring tree species from temperate rain forests in New Zealand. For each tree species, we quantified the functional traits of their green leaves and leaf, twig and wood litter and then decomposed the three litter types under controlled conditions. Below we show how the main findings of our study fit into the broader picture emerging from recent research into plant functional traits and litter decomposition.

Fig1. Oikos Blog entry for Jackson et al 2012

Posted by: oikosasa | January 15, 2013

Oikos in 2013: advancing synthesis in Ecology

Oikos’ Editor in Chief, Prof. Dries Bonte, presents some interesting news and wishes you all a wonderful 2013:

DriesA survey among readers revealed that Oikos is considered as a solid, high quality journal publishing broad ecological topics, often controversial papers and synthesising papers.  Synthesis in Ecology is already for long time our branding, but it is not always clear for readers and authors what is actually meant by that. For us, bringing synthesis is the only way to make serious advance in ecology. This can be achieved by merging different methodological, disciplinary, taxonomical or geographical aspects of ecology to create novel insights that move beyond providing the n-th case study on a certain ecological topic. While this rather confirmative research is intrinsically highly valuable, and inevitable to eventually create synthesis, Oikos will continue to prioritise the publication of the most novel, synthesising contributions. In a world flooded by scientific journals, such initiatives are essential to remain updated with the newest advances and insights in the field.

One new direction Oikos is heading for is the publication of meta-analyses as a separate section. Chris Lortie, our senior expert editor will be in charge of these incoming papers, evaluate proposals and invite original contributions. Dustin Marshall remains responsible for handling incoming Forum papers.

Authors publishing manuscripts that create synthesis –either meta-analyses, forum or regular papers- in Oikos will receive from 2013 onwards a real incentive, by providing fast publication, highlights of their work in the issue and social media, and open access. These papers will be highlighted as editor’s choice, and a box on the synthesis will be provided on each of these papers. In the near future, we will ask all authors to provide such a synthesis box at submission. When feasible, virtual issues centred on these synthesising contributions will be published.  In the near future, you can expect for instance such a guest-edited issue on Surf and Turf papers, and some more other exciting proposals have been received. More news on these will follow on our Facebook-page and on the Oikos-blog of course. On the other hand, Oikos will refrain from publishing rebuttal papers, but instead welcome balanced commentary papers that progress the field as a forum.

Oikos will further invest in the blog to show what Oikos is, communicate with readers, to serve authors with promotion of their papers. The base will be posts about papers in Early View that are provided by the authors. It could be photos, a background story to the study, a popular summary.  Essentially we seek for the blog answers on the following questions:  how did you get the idea, how long have you spent working on the project, any mistakes, why that species/system/field site etc.

As you can read, we do continue our investments to bring Oikos at the front in publishing the most exciting work in the field of ecology. We received about 1000 manuscripts in 2012 (of which we can print approximately 220 to keep the backlog rather limited). The editorial work is consequently only possible by having an extremely dynamics and motivated team, starting with the senior editors and 50+ handling editors that take fast and well-considered decisions on the incoming manuscripts, technical and managing editors processing all incoming and accepted papers, and of course, all our readers and authors that are engaged in the publication process by providing peer review of the highest quality. I truly thank you all for your work to support Oikos as a leading journal in ecology. My best wishes for 2013!!

Isn’t it just amazing how well adapted the tiny parasitic wasps are? Parasitoids want to lay their eggs in good, yummy caterpillars. Yummy caterpillars are those feeding on high quality plants. Quality of plants is partly determined by if their roots have been eaten by below ground herbivores. Plants smell differently above ground, depending on if their roots have been eaten or not. These odour variations are learned by the parasitic wasps when identifying the high quality hosts.

These results are presented in the new Early View paper “Effect of belowground herbivory on parasitoid associative learning of plant odours” by Marjolein Kruidhof and her co-workers. Here’s Marjolein’s own summary:

Only experienced parasitic wasps adapt their preference for plant odours in the presence of root feeders

Parasitic wasp laying eggs into a caterpillar

Although hidden in the soil, insects that feed on plant roots often do not go unnoticed by insects living aboveground. Upon root feeding, the odour the plant emits into the air changes. Tiny parasitic wasps, which lay their eggs inside the body of host caterpillars that feed on the plant leaves, use these plant odours to locate their hosts. Researchers from the Netherlands Institute of Ecology (NIOO-KNAW) in the Netherlands tested whether two closely-related parasitic wasp species, Cotesia glomerata and C. rubecula, expressed a preference for plants with or without Delia radicum root feeders. As inexperienced wasps of both species did not respond to the presence of root feeders, they continued to investigate whether the parasitic wasps could develop a preference after gaining experience when parasitizing caterpillars on root-infested or root-uninfested plants. Indeed, both wasp species adapted their preference for plant odours to the presence of root feeders, but did so in an opposite direction.  While C. glomerata learned to prefer the odour of plants with intact roots, C. rubecula learned to prefer the odour of root-infested plants. These findings stress the importance of not only assessing the influence of root herbivores on the responses of inexperienced parasitic wasps, but of also taking learned responses into account. In a publication that will soon appear in Oikos the authors discuss the possible reasons why these two parasitic wasp species respond so differently towards the presence of root feeders.


What are the chances that the reefs recover? And how likely is it that they just turn into seeweed-dominated ecosystems instead?  Important issues that Peter Mumby and his colleagues have studied and modelled in the new Early View paper “Evidence for and against the existence of alternate attractors on coral reefs”.

Here’s Peter’s summary of the study:

Coral reefs have been heavily stressed by local anthropogenic disturbances, like fishing and pollution, as well as global events such as ENSO which can cause coral bleaching and wreak devastation on living coral. Ideally, corals would recover after some kind of disturbance but a number of studies have documented a lack of recovery and even continued decline of corals rather than return to a coral-rich ‘attractor’. This raises the question, ‘do coral reefs exhibit multiple attractors?’. If they do, then it is possible for negative feedbacks to emerge that not only prevent reef recovery but reinforce themselves and trap reefs within an undesirable state, often dominated by seaweed. If reefs do become trapped in an undesirable state it might prove extemely difficult for management to reverse the decline and facilitate the return of a healthy ecosystem. 
Ecological models of coral reefs have studied the effects of various disturbances including the fishing of herbivores such as parrotfishes. Theory predicts that Caribbean coral reefs do indeed exhibit alternate attractors particularly in their somewhat degraded states today. However, empirical studies have claimed to find no evidence to support this theory. There is, therefore, a controversy over whether reefs can become trapped in seaweed-dominated systems. In this paper we argue first that the empirical studies were incapable of testing for multiple attractors. We then provide new comparisons between theoretical predictions and field observations, both of which are consistent with multiple attractors. However, it is also possible to fit a simpler model to empirical data that does not exhibit multiple attractors. When we take a careful look at this model we find that it makes several troubling ecological assumptions, which lead us to doubt its veracity.
Proving the existence of multiple attractors is extremely challenging and there is, as yet, no definitive proof either way. However, the weight of theory and field observation appears to support the notion for Caribbean coral reefs. Given this, and it’s important conservation implications, we feel that management should proceed on the conservative – and more likely – assumption that reefs can become stuck in seaweed states if stringent steps are not taken to increase their resilience.
Posted by: oikosasa | December 18, 2012

Playing dead – when not needed to

The Ecology of Playing Dead – when not needed to…something that Xinqiang Xi, John N. Griffin and Shucun Sun have diged deeper into in their new Early View paper “Grasshoppers amensalistically suppress caterpillar performance and enhance plant biomass in an alpine meadow”.

Read Shucun Sun’s story about Playing dead behaviour in grasshoppers:


As a child, I would often wake in the middle of the night thinking I could hear a burglar in the kitchen downstairs (in reality, my family cat coming through the cat flap). I would lay there, alert in bed, not daring to move in case I would be heard. By mistaking sounds of the cat for those of a burglar, I had inappropriately employed a danger avoidance strategy, costing myself much-needed sleep. We know that, in nature, prey are often highly-tuned to the signals of their predators and take action to avoid predation, like growing defensive body armor, shifting habitats, or even playing dead. Prey take these energetically demanding measures because being eaten tends to be rather more costly to one’s fitness! However, just like my childhood anecdote, prey species can get it wrong and misidentify a friend for a foe, reacting to cues from animals within their trophic level (competitors) that pose no predation threat. This sort of interaction could be common in nature and may not only incur a cost for the ‘victim’ but also have knock-on effects to other species that interact with them.

In our paper, we describe and explore the direct and indirect consequences of interactions between two common grazing insects in alpine meadows of the Tibetan Plateau in northwestern China. We ran a season-long field experiment in which we manipulated the presence and absence of the caterpillar, Gynaephora alpherakii, and grasshopper, Chorthippus fallax, in enclosures, and measured responses of both grazer species and their plant resources. After two months we discovered a strong negative one-way interaction between these species – the seldom considered form of interaction known as amensalism. While caterpillars showed reduced growth, survival, egg production, and delayed metamorphosis in the presence of grasshoppers, there was no reciprocal negative affect of caterpillars on grasshoppers. Because caterpillars are voracious grazers, changes in their activity and survival caused by the presence and absence of grasshoppers propagated to influence the composition and biomass of plants.

We put the amensalistic interaction down to a case of mistaken identity. We observed that by whacking into – and landing heavily upon – grass stems as they move about the meadows, grasshoppers trigger a death-feigning response in caterpillars whereby caterpillars, upon perceiving risk, drop to the ground from the grass stems and leaves where they forage, cease movement, and curl up for about 20 minutes before resuming foraging. Repeated disturbances from the seasonally abundant grasshoppers could have significant effects on feeding time and energy uptake. Indeed, caterpillars in the same enclosures as grasshoppers were observed actively foraging significantly less frequently than when they were alone – evidence of the cost of mistakenly playing dead and helping to explain grasshopper effects on caterpillar growth, timing of metamorphosis, and grazing impact on plants.

Our study provides a rare example of amensalism in a natural ecosystem and shows that it can result from a previously unappreciated mechanism – mistaken identity. Furthermore, this work highlights that such interactions can have significant consequences for the functioning of ecosystems, as revealed by marked shifts in the relative abundances of plant functional groups and overall biomass. Strong amensalistic interactions, if common, could have consequences for our understanding of key issues, such as the evolution of risk-reducing behaviors and traits and the link between consumer biodiversity and ecosystem functioning.

Posted by: oikosasa | December 14, 2012

The Arctic tundra as a natural laboratory

In the new Early View paper “Predator-mediated interactions between preferred, alternative and incidental prey in the arctic tundra”, Laura McKinnon and her colleagues used the Arctic Tundra in Canada as a natural laboratory to study predator-prey interactions.

20708cHere is Laura’s short version of the paper:

Predators can have direct impacts on prey populations by decreasing survival and fecundity, and in turn, prey populations can also drive predator densities.  These interactions between predator and prey can often lead to coupled cycles in population abundance, many studies of which have become classic textbook examples in ecology.  More recently, these models have been expanded to incorporate multiple prey species and even multiple trophic levels in order to have a better understanding of the causes and consequences of predator prey interactions in more complex realistic environments.  However, testing these models in complex ecosystems can become rather cumbersome due the sheer number of interactions between species.  Luckily, there are some terrestrial ecosystems, such as the Arctic tundra which provide less complex natural laboratories in which to study trophic interactions between predators and multiple prey items.   In our recent study, we took advantage of this natural laboratory to study indirect interactions between preferred, alternative and incidental prey.


In the arctic tundra, numerical and functional responses of predators to preferred prey (lemmings) affect the predation pressure on alternative prey (goose eggs) and predators aggregate in areas of high alternative prey density.  Therefore, we hypothesized that predation risk on incidental prey (shorebird eggs) would increase in patches of high goose nest density when lemmings were scarce.  By measuring predation risk on artificial shorebird nests in quadrats varying in goose nest density on Bylot Island (Nunavut, Canada) across 3 summers with variable lemming abundance, and monitoring quadrats for predator activity, we provide evidence that the abundance of preferred prey influences the indirect relationship between alternative and incidental prey.  Predation risk on artificial shorebird nests increased in the presence of increasing goose nest densities, especially at low lemming abundance, as predicted.  In addition to supporting our incidental prey hypothesis which suggests that when preferred prey decrease in abundance, short-term apparent competition via aggregative response can occur between alternative and incidental prey, these results also provoke interesting applied questions regarding the potential effects of increasing goose densities on incidental prey such as shorebirds.


Posted by: oikosasa | December 13, 2012

Opossums’ seed dispersing job

Seed diseprsal by animals is an important ecological service. How selective or general the animals are in their choice of fruits to eat might have a huge effect on dispersal of the plants. Read more in the new Early View paper “Individual variation in resource use by opossums leading to nested fruit consumption” by Mauricio Cantor et al.

Here is the authors’ own summary of the paper:


Seed dispersal by fruit-eating vertebrates is an important ecological service that has consequences for the plant community and regeneration process. Despite recent findings on the ecological relevance of within population diet variation far less attention has been devoted to the role diet variation for ecological services, such as seed dispersal. In this paper we unravel fruit consumption patterns by the white-eared opossum (Didelphis albiventris), a South American didelphid, which is regarded as an important seed disperser commonly found in disturbed environments, where vegetal regeneration is especially required.

opossum4_SetzWe detected fruit consumption patterns suggesting these opossums may differ in their degree of fruit selectivity what may result in heterogeneity in seed dispersal efficiency within the population. In this sense, the actual result of the seed dispersal provided by these animals probably differs from what one would expect from the average behavior of the population. The result of such heterogeneity would probably be dependent on the proportion of opportunistic and selective individuals in the population. This frequency-dependent seed dispersal may have implications to both plant individuals and species, affecting plant performance and the local plant community composition.


Posted by: oikosasa | December 12, 2012

Will your photo be on Oikos cover 2013?

249518_413427882044243_950633876_nOikos is changing it’s cover style in 2013. Replacing the quote, there will now be a photo. We therefore, as an annual competition, call for photos illustrating the Oikos’ goal of Synthesising Ecology. We seek a photo also demonstrating ecology in action (e.g. processes or interactions), not only a single organism or a landscape.

Please send your photos together with the oikos-photo-competition-form2 to, with Photo competetion as subject, before January 31st 2013. The winner will be awarded a book price from Amazon for a value of 100 Euro. The winning photo will be at the cover of all issues of Oikos from April 2013-December 2013. A selection of contributions will be exhibited at the Oikos meeting in Linköping, Sweden Feb 4-6.

Competition Rules:

Entries must be digital images, submitted electronically, in jpg or tiff-format. Images must be available in 300 ppi.

Digital enhancements must be kept to a minimum and must be declared. Both the original and the enhanced image must be submitted.

File names must include appplicant’s surname.

Photos must be accompanied by an entry form that describes illustrated species and scene. Download the oikos-photo-competition-form2

A prize committee consisting of Managing Editor, Editor in Chief, deputy editors, Technical Editor of Oikos and the Director of the Oikos Editorial Office, will judge which photo that best suits our requests. The decision by the committee is final.

All submissions will be entered under a Creative Commons License and will be displayed on Oikos webpage and social media and may be used  for commercial purposes. Download Creative Commons License here.

Oikos takes no responsibility for submitted images being lost, damaged or dealyed.

Posted by: oikosasa | December 10, 2012

Winners in a changing world

Invasive species may actually increase resistance to climate changes. Celia Olabarria and co-workers studies this interaction in marine macroalgal assemblages.  Now on early View: Response of macroalgal assemblages from rockpools to climate change: effects of persistent increase in temperature and CO2

Here is a short summary by the authors:

Climate change is one of the greatest threat  that marine systems are facing. Changes in ocean temperature, biogeochemistry, sea level, UV radiation, and circulation patterns have been identified over the last few decades. Specifically, warmer and more acidic oceanic water (due to the increase of CO2 in the atmosphere and oceans) are of great concern to marine biologists. Non-indigenous species are also impacting marine communities around the world at an unprecedented rate. These species are often ecosystem engineers (e.g. brown canopy algae) that can replace native species and their functional role in the ecosystem, or modify habitat characteristics and food sources for consumers. We do not have information about how invaded communities will respond to climate change compared to non-invaded communities.

Marine macroalgae that dominate the rocky intertidal in most oceans, and in temperate and Polar regions cover rock surfaces in the shallow subtidal, make a substantial contribution to marine primary production (10%) and describe important ecological functions. They may be also actively involved in lowering global warming and climate change. Research about effects of different climate change scenarios on macroalgae has found quite variable and species-specific responses. Until now, most research has focused on the effects of climate change on single macroalgae species, rather than on whole communities. While this approach is useful for understanding species-specific mechanisms behind the effects of environmental changes, it ignores species interactions which may buffer or amplify individual responses thereby altering predicted assemblage-level responses.


Macroalgal assemblages from rock pools are interesting model systems to study climate-driven changes because they are composed of different morpho-functional groups of varying diversity and identity of species. Despite coping with daily and seasonal variations in pH and temperature, their response to more persistent changes are unknown. We were able to manipulate temperature and CO2 concentration in mesocosms to evaluate how these to climate-change factors affected several ecosystem functioning variables at both individual and assemblage level. For that, we used synthetic macroalgal assemblages of varying diversity and identity of species resembling those characteristic of rock pools.


Results revealed that the increase in temperature and CO2 concentration may interact and affect the functioning of coastal macroalgal assemblages, with effects largely dependent on species composition of assemblages. Although the effects of assemblage richness were mostly negligible, significant differences were found between the response of native and invaded assemblages. Data suggested that  invaded assemblages might be more resistant in the predicted future scenario of climate change. This paper emphasises the importance of using multiple stressors-study approaches at community level to get better predictions of climate change impacts on ecosystem functioning.

Photo: F. Arenas and M. Matias

Posted by: oikosasa | December 7, 2012

High-fat food makes females unattractive

Protein or fat in food – which is best? Well, if you’re a female preying mantid, you should definitely go for the high-protein diet! Females on high-lipid diet attract much fewer males than females on high-protein diet. These results are presented in the new Early View paper “Macronutrient intake affects reproduction of a predatory insect” by Katherine L. Barry and Shawn M. Wilder.


Here is a short summary by Katherine:

164bWe tested how diet affected the reproductive success of female praying mantids by feeding them live locusts that were injected with solutions of lipid or protein.  Not too surprisingly, females fed high-lipid locusts gained more fat and produced about half as many eggs as females fed high-protein locusts. 

We also tested female attractiveness by placing females in small mesh cages (that excluded visual cues) within large enclosures, and allowing males to choose between females from the different feeding treatments.  Usually females with more eggs are more attractive than females with less eggs and, in our study, the high-protein females attracted more males (56 males) than the high-lipid females (1 male).  However, the effect was much more extreme than we predicted.  In previous studies, females were fed a standard diet of crickets, and individuals with as few as one egg were able to attract up to three males.  But in our study, females on the high-lipid diet had over 20 eggs on average but only one female attracted one male.  Hence, diet quality seems to have a large effect on the quantity or quality of pheromone produced by females.  It would be interesting to test how diet mediates pheromone production in praying mantids and if similar effects occur in other species of arthropods.


Posted by: oikosasa | December 6, 2012

Are you a helper?

Do you have any “helper” around you? Maybe are you one yourself? “Helpers” are those researchers who regularly provide valuable feedback to their colleagues’ manuscripts and to scientific discussions.  Who regard this feedback as part of the research, and a part of their working tasks. However, their input is awarded as best with their names in the acknowledgement of the publication, and not that often in the author field.

Alexander Oettl, a professor in Immunology at Georgia Institute of Technology, Atlanta, USA, studied the effect of “helpers” by comparing their colleagues’ impact of papers (IF of journals, n publications and citations) before and after the “helpers” involvement.  What he found was a clear positive effect of the involvement of the “helpers” for their colleague’s publications.

The question is – how are these helpers awarded? In evaluations of applications for academic positions and research grants, factors as large numbers of highly cited papers get higher rates than increasing over all scientific quality in the group or at the department. Perhaps it’s time for a new metric to take into account – average acknowledgements per year?

Read Oettl’s paper in Nature here  (Figures from Oettl’s paper)

Posted by: oikosasa | December 4, 2012

Top of the pops

You can now find a list of the most cited Oikos papers 2011, that were published in 2009 and 2010, on our webpage.

On top of the list,  is “A consumer’s guide to nestedness analysis” by Werner Ulrich, Mário Almeida-Neto and Nicholas J. Gotelli.

Here is a short description by Werner Ulrich, on what it’s all about:

wernerEcologists look for patterns in nature. The nested pattern – in which the composition of small assemblages is a nested subset of larger ones – is one that received a lot of attention, both because it is so simple and because it is so common. In biogeography, if sites are ordered by area or along an environmental gradient, a nested pattern can be interpreted as an orderly loss of species along the gradient. This is the most common interpretation of nestedness. It was popularized in the 1980s by Bruce Patterson and the late Wirt Atmar, who introduced a nestedness temperature calculator, compiled a large set of ecological presence-absence matrices from the published literature, and detected nestedness in most of them. Since then, much research has been devoted to articulating alternative mechanisms for nestedness, and developing appropriate metrics and null models for testing the pattern. Nestedness has also been used in food web or species interaction analysis, population genetics, and even molecular biology. However, the nestedness tale is also a story of failure and a warning on the challenges of statistical pattern analysis in ecology. Many studies have unfortunately used ad hoc measures of the degree of nestedness, inappropriate statistical benchmarks, and questionable ecological arguments. That was the point where we (Nick, Mario, and I) stepped in. The origin of our “consumer’s guide” paper was from an idea of Mario’s, who noticed that the quantification of a nested pattern went into a wrong direction. He asked me to take part in the development of a new metric, and the resulting Oikos paper was a success. We then tried to give guidelines for proper pattern identification and testing. During the writing, we noticed how many snags even a simple pattern like the nested one provides for researchers. Apparently, many other scientists shared our views. Our impression is that the quality of nestedness research has improved during the last few years, and we hope that our review has contributed to that trend.

During the work on nestedness, we started developing new metrics to quantify observed patterns and expanded the framework for proper statistical testing. Two new Oikos papers by Nick and me on statistical challenges and on pattern detection in ecology are the fruits of these efforts. We can only hope they will become as popular as the “consumer’s guide” to nestedness.’

Posted by: oikosasa | November 30, 2012

Are women too busy householding to write Nature papers?

Do you remember the Correspondence in Nature about contributions by women to Nature News and Views, that I wrote about here earlier this autmun? Obviously, the paper made the editor’s of Nature to analyze their situation and to come up with a solution to the problem. The recipe is to ask all editors to make an extra “concious loop” to identify five women to ask when commissioning articles and similar tasks. Most interesting though, is the statement that ” But it is certanly the case that women typically spend more time than men as housemakers and looking after children, further reducing the time available for journal contributions”. I wonder – how many times have Nature editors got that reply from an invited woman? -Sorry I don’t have time to write an invited paper to Nature, have to look after the kids you know? I’m pretty sure that there is no single female scientist out there who makes a choice between householding and writing Nature papers.

Here is Nature’s reply

But I’m curious – are the authors of the original paper happy with the response they have got? From Nature and from others? I asked one of them, Johanna Stadmark some questions:

Johanna_Stadmark_foto1. How much have you and Daniel been involved in the response article? Got the chance to read it before publication?

Nothing, we did not know it was coming, and were happily surprised last Thursday.

2. How easy was it to get Nature publish a paper critisizing their work?

They immediately showed an interest in our study, but with revisions and comments back and forth it took some time. A correspondence should view our opinion, so we did not want to accept all suggested revisions. Nature edited our piece, but we had the possibility to make changes. I think it is of utmost importance for the journals to also accept criticism on their work, it shows that they are serious in their work.

3. What do you think of their reply? And about their suggestion to solve the problem?

I am happy that the idea to think outside of your own network was one thing that they suggested. If you reflect on how you are doing things you also have the possibility to make changes where necessary.

4. Do you think things will change now?

I do. The aim of our piece was to point at an unconscious bias that is occurring, not only in the leading science journals, but also at conferences, workshops etc. Over the last days we have received emails from people telling us where the Nature Editorial has been distributed and if some of these people change the way of selecting people for different tasks we have succeeded.

5. What advice can you give Oikos’ editors to avoid gender biases? (We have just started to invite authors to write forum papers, for example).

Have a protocol, to avoid using the “standard network”. Go and find the best authors irrespective of gender or ethnicity or other irrelevant conditions!

6. And finally, How big do you think, the problem of women spending more time than men householding and caring for children, is for invited papers in Nature?

I do not think that is important. Approximately half of the invited authors are full professors and if you have come that far in your career you have been able to deal with the so-called double tasks. And if you are invited to write a piece like a News & Views- or Perspectives article you do not want to miss the opportunity and you would give it a high priority.

I think the householding and caring for children in some cases can play a role in the advancement of the career and what kind of work you choose (teaching, research, administration). However, there are countries where public day care has been available since the 70’s and where caring of children should not be a task designated to women only. (I know it takes a long time to change society, and we are still not there, but to use “caring for children” as an explanatory parameter is not a good way to go in the discussions of the future, since it could be a fulfilling of an unwanted condition.

Posted by: oikosasa | November 29, 2012

Do we publish too much?

H-index, Impact Factor, citations, number of publications per year – metrics all around the scientist. The currency of science. Has it gone that far that the metrics is about to kill scientific quality?

This “quantity mantra” – the obsession with measuring scientific quantity – and not quality- was recently criticized by Joern Fischer, Euan G. Ritchie and Jan Hanspach in TREE. They argue that metrics has lead to an increased number of publications, larger research consortia and more administration. More papers published means more time spent on reading papers, reviewing papers and editing papers. With a general limit of 24 hours per day, that inevitably means less time for other activities. And it’s particularly reflection time and time spent to stimulate creativity that is suffering most, according to Fischer et al. This in turn, leads to decreased quality of science. Is this the way we want to go? The paper finishes with “Starting with our own university departments (but not stopping there), it is time to take stock of what we are doing. We must recreate spaces for reflection, personal relationships, and depth. More does not equal better.”  The question is, How?

Good place for reflection…

As a reply to Fisher et al.’s paper, Panu Halme, Atte Komonen and Otso Huitu transfer the problem from individual researchers and departments to science politics and funding strategies. They argue, that the main problem lies in the absence of scientific thinking among senior scientists. “Senior scientists rarely enjoy the luxury of having time to read about and contemplate the theory of their field, let alone participate in the gathering of primary data in the field or laboratory. Halme et al.’s solution to this problem, and suggested mean to leave room for slower science and increased quality, is to limit the numbers of students associated with each professor, and funding forms enabling seniors to focus exclusively on science.

In a reply, Fischer et al. actually comes up with a number of hands-on solutions, both for individual scientists, department leaders, science politicians and decision makers and for funding agencies.

Is it the increased quantity of publication that actually causes the increased stress for scientists? And how should the problem best be solved? Bottom up or top down? How do you release time to think deep, scientific thoughts and to reflect over your research?

Fischer et al.’s “Academia’s obsession with quantity

Halme’ et al.’s Solutions to replace quantity with quality in science

Fischer et al.’s “An academia beyond quantity…”

Posted by: oikosasa | November 28, 2012

New Editor: Matty P. Berg

Let me introduce you to our new Subject Editor, Dr. Matty P. Berg, Vrije Universiteit Amsterdam, the Netherlands.

– What gets me out of bed every morning is the question what determines the diversity and composition of soil fauna communities, Matty says.

 What’s you main research focus at the moment?

My research focuses on the role of trait diversity in community and ecosystem ecology and can be divided in two major research areas.The first focal point is on the role of traits, both inter- and intra-specific, for the regulation of community structure. I measure functional traits of soil fauna, especially terrestrial isopods and springtails and use field experiments and trait analysis to study temporal and spatial changes in soil invertebrate community composition, at a hierarchy of spatial scales. The second focal point is on the role of traits in ecosystem ecology.This focal point comprises work on the role of trait diversity, both on a  species and community level, for the regulation of ecosystem processes. I measure traits and conduct experiments to understand how environmental variation influences ecosystem processes, trough alteration of species composition and interactions, using a response-to-effect trait framework. More recently I start to get interested in the importance of trait variability and plasticity in these research areas.

Can you describe you research career? Where, what, when?

I have studied Biology at the University of Amsterdam, with a major in Ecology, Biogeography and Taxonomy (1988-1992). During my internship I have studied the effect of changes in springtail abundance on the fat storage in carabid beetles and their reproductive output in coniferous forests. I did my PhD at the VU University, Amsterdam on the effects of enhanced atmospheric nitrogen deposition on soil food web structure and how changes in food web composition affect C and N dynamics in soils (1992-97). After that I did a Post-Doc at the Swedish University of Agricultural Sciences (Uppsala, Sweden) where I studied how competition between two functional groups of Basidiomycete fungi effected wood decomposition (1997-98). About 1.5 years later I returned to the VU university were I was appointed for five years as a Royal Dutch Science Academy-fellow. During this period I studied the effects of species richness and composition on the resilience of springtail communities to extreme events and the role of species composition of macro-detritivores for litter decomposition  (1999-2004). Since then I have an appointment as an Assistant professor (till 2011) and currently as an Associated professor in Soil Community Ecology. My main focus is currently on spatial ecology and on functional diversity.

How come that you became a scientist in ecology?

I am a true field ecologist. Already when I was young my main interest were found outdoors. My grandfather took me out to the Dutch polders on Wednesdays and introduced me to hares, wetlands birds and aquatic life. I guess like most scientists I started with birds and plants and was wondering why species occur where they do. The reason why I took up Biology was that I wanted to know how the natural world around me works. How are natural communities maintained? How do all these species interact? What is determining their composition? This question still lays behind most of the projects I am currently working on or are involved in. I have a second interest in the taxonomy and systematics of soil fauna, but during my BsC it became clear that career wise this was not the avenue to take. This is something I keep for my spare time.

What do you do when you’re not working?

To be honest the line between work and hobby is very thin. Natural history is my passion and in my spare time I can be found outdoors looking down for soil animals (or up for birds). I am a member of the European Invertebrate Survey, a society that aims to increase the knowledge on the distribution, ecology and protection of invertebrates. The society is based at the Naturalis Biodiversity Centre, Leiden where I am an associated researcher. As co-ordinator of the isopods, centipedes, millipedes, and collembolans survey groups  I make regular field surveys all over the country, study museum collections, describe new species for the Dutch fauna, make identification keys and try to make others interested in the wonderful world of soil critters. But I can also appreciate good music, nice food, and I am a sucker for a good glass of single malt whiskey to be consumed  in company of friends or colleagues.

Posted by: oikosasa | November 27, 2012

Seed size have demographic consequences

So those small small seeds produced by plants have actually big effects on plant demography. Read more in the Early View paper “Non-native conditions favor non-native populations of invasive plant: demographic consequences of seed size variation?” by José L. Hierro et al. 

Or be quicly updated by Josés own short summary:

We conducted a reciprocal common garden in part of the native (southwestern Turkey) and introduced (central Argentina) range of a globally distributed plant invader, Centaurea solstitialis (yellow starthistle, Asteraceae) to explore the idea that the demographic success of the species in Argentina relates to differences between native and introduced populations.   Unusual among common gardens, our experimental design included seed additions to explicitly evaluate population level responses.  We found that seed mass was two times larger for Argentinean than Turkish populations.  Similarly, plant establishment at the end of the experiment was greater for Argentinean than Turkish populations, but only in the common garden in Argentina.  In Turkey, we detected no differences in plant establishment between population origins.  Our results suggest that increased seed size in Argentinean populations may have demographic consequences under central Argentina conditions that can contribute to the invasive success of C. solstitialis.  Our study offers the most complete evaluation to date to the idea that variation in seed size can contribute to differences in plant density between native and non-native distributions of invasive plant species.

Field site in Turkey (native)

Field site in Argentina (introduced)


Posted by: oikosasa | November 23, 2012

Heavy work in community ecology

When I did an undergraduate project at Silwood Park, my supervisor, Hefin Jones used to say that ecological research is about 10 % inspiration and 90% transpiration. And this is exactly what Winfried Voigt report about in his story about his and his colleagues Early View paper “Bottom–up and top–down forces structuring consumer communities in an experimental grassland” (Rzanny et al.). He story also shows what might be the outcome of large collaborative projects.

Gathering up sufficient and useful data for answering questions concerning entire communities is always a strenuous and costly job. It is actually only feasible when working in cooperation with a large team. We were lucky to be involved in an appropriately large team, the Jena Experiment, a controlled biodiversity experiment []. The dimensions (10 ha, 80 plots each 20×20 m with a set plant species diversity of 1, 2, 4, 8, 16 and 60 as well as 1,2,3 or 4 functional plant groups, and numerous smaller plots) are unique and  turned out to be the right platform for asking “bigger” questions about structure and function in grassland communities. A lot of periodic work, in particular weeding, was done by a capable maintenance staff (5 professional gardeners and numerous student assistants) so that the only thing left to do was to collect our own data. Nevertheless, for our closer small team (with some support  of a few student assistants) even that was quite a strenuous job but all the effort and suffering (not to say blood, sweat and tears) are not  always obvious if one looks at the end result on just a few hundred Kbyte of data we hold in an excel file. We collected arthropods 5 times, from May to October in 2005, on 5 quadrats randomly placed within the core area of 50 big plots (16 monocultures, 16 four-species, 14 sixteen-species and four 60-species mixtures) using suction samplers combined with biocenometers (see photograph) as well as using pitfall traps. All in all, we successfuly accrued 322 arthropod species/taxa with 81658 individuals that we could exploit in the end.

Identifying the key factors for structuring ecological communities is at the heart of ecological research. Most studies dealing with this question on community level rely on lumped, aggregated variables such as summed species abundance, biomass or diversity measures or they confine to a small part of species usually one or a few taxa.

We already developed a different approach 10 years ago by assigning all species to functional groups representing approximately the entire community. Because we hold all functional groups as matrices containing abundances of their members (species), we acquire a sufficient simplification, while retaining full species information. As we see ecological communities as a system of interdependent functional groups, we performed an exploratory multivariate analysis, explicitly addressing species composition of functional groups. We used species resolved plant biomass and arthropod abundance data from the Jena Experiment to estimate the dependencies among plant – and consumer functional groups, thereby accounting for spatial effects and differences in soil conditions.

Using a set of five groups of biotic and abiotic predictor variables (Plants, Herbivores/Detritivores, Carnivores, Soil, and Spatial patterns), we aimed to determine the independent and shared fractions of variation explained by these variables in the composition of all consumer functional groups. Depending on the trophic level of the predictor variables, we quantified the relative roles of top-down and bottom-up effects.

It turned out that legume composition explaines the highest fraction of variation in virtually all consumer functional groups, indicating that legumes play a key role in controlling multiple ecosystem processes. Both plant species richness and plant functional richness show significant effects on (nearly) all functional groups, however, the fraction of variation explained is always exceeded by the fraction explained by plant community biomass. Carnivore composition explain significant fractions of variation in many functional groups, the same applies for the soil and space variables. Consequently, we conclude that bottom-up effects seem to play the most important role in structuring the consumer communities in our experimental system, but at the same time top-down effects are still important for the majority of arthropod functional groups.

Posted by: oikosasa | November 22, 2012

With inspiration from the past

Sometimes it’s worth bringing good old science back into the light. Hideyuki Doi and Terutaka Mori were inspired by two papers from 1932 and 1953 about species abundance distirbution and brought them into modern days’ science. Read the paper “The discovery of species–abundance distribution in an ecological community” on Early View. Here’s the author’s own background story:

Species–abundance distribution (SAD), representing relative species abundance, is one of the most basic descriptions of an ecological community. The description can represent more detailed attributes of the community than species richness. Universal observations that few species in a community are dominant, but that many more species are rare, can be neatly encapsulated in a SAD, but not represented by species richness.

Prof. Isao Motomura (1904–1981, photo) first found a SAD pattern for some animal communities and then published a notable paper in 1932. Motomura (1932) described SAD in the following way: ‘In a community, there are generally many more species with relatively low abundances. When the species found within a quadrat are ranked according to abundance (i.e. the order of dominance in the community), a definite graphic pattern is observed between the rank and abundance of species’. He found that a straight line is produced when logarithm of abundance is plotted against rank, and then fitted observed SAD to “geometric series”. Motomura’s study is the first discovery of a SAD pattern, but has often been overlooked or incorrectly cited, probably due to being published in Japanese.

In this article, we in-deep introduce the works of Motomura and the subsequent research history of SAD. Specifically, we also introduce the work of Numata et al., another Japanese paper, which provided the biological explanation for Motomura’s model of SAD. Numata et al. (1953) showed that Motomura’s model (i.e. geometric series) is explained by supposing that species occupy the available area according to the rank of a set of ability for individual and species survival (i.e. reproduction, competition, etc.). Therefore, they provided biological explanations with a deductive approach for Motomura’s model in which an inductive statistical approach was employed. We believe that the field of SAD is increasing in importance and activity, because SAD has proven to be one of the most important fundamental tools in community ecology and management. Motomura (1932) paper also includes an important suggestion for ecologists: ‘In a natural ecosystem, it is very unusual to find such geometric series for the abundances of species coexisting in a habitat’. The finding of such a surprising pattern in ecological communities therefore represents a frontier of ecological research. Our motivation for finding a new general rule in ecology is highly recommended.

Posted by: oikosasa | November 21, 2012

Sex in plants depends on their neighbours

Root competition appears to effect sex allocation in plants. Åsa Lankinen and her colleagues have studied this in the Early View paper “Allocation to pollen competitive ability versus seed production in Viola tricolor as an effect of plant size, soil nutrients and presence of a root competitor”. Here is a short summary by Åsa:

Even though plants lack brains, there is clear evidence that they can perceive and respond to their neighbours. For example, in some species plants can sense airborne chemicals transmitted from the leaves of another plant attacked by herbivorous insects, acting as a cue to start the induced defence system. Another example of plant communication is the possibility to detect the presence of self vs. non-self roots in the soil. Presence of unrelated root neighbours can even cause plants to allocate relatively more resources to their roots than to their shoots, thereby allowing more effective root-uptake when competitors are present. But can plants also use these kinds of cues to optimize their mating success, such as altering relative allocation to male versus female function in hermaphroditic plants depending on the presence or absence of competitors? In hermaphrodite animals, the social context (e.g. group size) can clearly influence male-female allocation.

In this study on violets, a hermaphrodite annual, our results indicate that sex allocation may not only be size dependent and influenced by soil nutrients, but also affected by presence of a root competitor. Taking the additional aspect of social environment into account also in studies on sex allocation in plants has the potential to increase our understanding of sex allocation across taxa.  This knowledge might help us answer difficult questions such as how evolutionary transitions can occur between breeding systems.

Posted by: oikosasa | November 16, 2012

Effects of monoculture on plant litter decomposition

In the new early view paper “Do physical plant litter traits explain non-additivity in litter mixtures? A test of the improved microenvironmental conditions theory”, Marika Makkonen and co-workers, present a new theory on decomposition rates. Here’s their own summary of the paper:

Terrestrial plant litter decomposition is a key component in carbon flux models. The models and thus the predictions they produce could be improved by ensuring the comprehensiveness of the variables included in the model and the close resemblances between nature and the input data. Usually the input data is derived from litter monoculture studies and this creates a crucial source of error, as monocultures do not present well the majority of land cover. Importantly decomposition rates usually differ between litter monocultures and mixtures. The causes for this non-additive effect are still debated and unclear. One plausible theory suggests that the non-additivity of litter mixtures derives partly from improved microclimatic conditions given by physically more diverse plant species in mixtures compared to monocultures. The physical characteristics of litter determine e.g. water acquisition and retention and thus alter the microenvironmental conditions determining the habitat and resource availability for decomposers.

We tested this theory in a dry subarctic birch forest in the Swedish Lapland in two contrasting moisture conditions. By testing some water holding capacity (WHC) traits, we found clear support for this theory and thus our results strongly encourage the inclusion of plant litter physical traits as the predictors of the decomposition rates. Yet the modeling will face more challenges as we found the direction of non-additivity (positive or negative deviation compared to monocultures) in litter mixtures to vary between climatic (moisture) conditions. Namely we found that the higher dissimilarity in WHC traits between the component litter species in a mixture increased synergistic effects in litter mixtures under limiting moisture conditions whereas, increased antagonistic effects were observed under improved moisture conditions. We also observed differences in non-additivity, its relation to WHC traits and their modifications by different climatic conditions between litter mixtures of varying decomposability further obscuring the process. Although the non-additivity of litter mixture remains complex, some major advances were made by this study.

Posted by: oikosasa | November 15, 2012

How good isn’t a reject?

A couple of weeks ago, I wrote here about the close connection between failure and success. And associated it with improvement of a manuscript due to a reject. Now, I also found some scientific support for this. Vincent Calgno and his co-workers have tracked the history of more than 80 000 scientific papers, published between 2006 and 2008 within the bioscience area. They found that papers that had been rejected in one journal and submitted and accepted in another one, gathered significantly more citations than papers accepted on the first try. Even if they were published in the same journals. Despite that 75% of the papers were published in the jornal it was first submitted to, the proportion of papers that had been submitted elsewhere, was actually higher for high impact journals such as Nature and Science, than it was for low-imapct, specialized ones.

So no more tears over rejects! Things will only be better!

So how good will not this one be?:

Posted by: oikosasa | November 13, 2012

Why red leaves?

At least here in southern Sweden, the autumn colours have been fantastic this year! As an evolutionary ecologist one starts wonder: why does trees differ in level of coloration? Is it only a benefit to the tree? Or are there costs associated with it as well? And why are some leaves red early in spring? In the new Early View paper, “Red young leaves have less mechanical defence than green young leaves”, Ying-Zhuo Chen and Shuang-Quan Huang have found answers to some of these questions. Here is a short version by Shuang-Quan Huang:

People in North Temperate Zone often enjoy seeing colorful leaves in autumn, an obvious phenomenon in deciduous forests. Evolutionary biologists Hamilton and Brown (2001) considered that autumn leaf coloration is expensive because it involves the costs of pigment synthesis, resource loss and loss of primary production (photosynthesis). A functional hypothesis proposed by Hamilton & Brown (2001) and Archetti (2000) suggest that leaf redness could be an adaptive strategy as a warning signal reducing insect attack (anti-herbivory hypothesis), but is still largely controversial.

Many species have red young leaves in spring. For example, an investigation of tropical plants in a Nature Reserve, Singapore showed that 60% species with young leaves were red (see Dominy et al. 2002). The anti-herbivory hypothesis has also been adopted to explain color change during leaf development. We are interested in why so many species produce constant green leaves in its life cycle if leaf-color change involves an obvious benefit (less herbivory). A similar question was asked by David Lee (2002) who argued that if anthocyanins in leaves confer some physiological/selective advantage, how do the species lacking anthocyanins compensate?

To test whether green leaves reduce herbivory by physical defense as an alternative to the supposed warning signal of red leaves, we conducted comparative analyses of leaf color and protective tissues of 76 woody species around our campus Wuhan University, a subtropical area in central China. We found that the species with green young leaves showed a significantly higher incidence of enhanced cuticle, multiple epidermis, and trichomes compared to species with red young leaves. This analysis suggests that green leaves may compensate for the lack of anthocyanins by adopting enhanced physical defense. Our finding of relatively poor mechanical protection in red young leaves may provide new evidence for the adaptive explanation of leaf color change.

Posted by: oikosasa | November 12, 2012

New Oikos SE

It’s really nice to be able to present yet another new Oikos Subject Editor:

Shawn Wilder, University of Sidney, Australia.

1. What’s you main research focus at the moment?

My main research focus now is examining the nutritional requirements of spiders and comparing these requirements to the distribution of nutrients in prey to better understand how diet regulation behavior by predators affects the structure and function of ecological communities.  Recent work has shown that the nutrient content of prey can have large effects on the growth and reproduction of predators and that some predators will tightly regulate their diet.  I’ve been using the geometric framework of nutrition to quantify the nutrient requirements of a spider (redback spider, Latrodectus hasselti) and have measured the nutrient content of over 500 species of arthropods.  Future experiments and modeling work will combine this information to predict which prey or combinations of prey may be preferred by predators and how these prey preferences may affect prey populations and community dynamics.

 2. Can you describe you research career? Where, what, when?

My career began by helping with fieldwork on charismatic megafauna.  During undergrad, I was a field assistant on large-scale studies that captured, radio-collared, and tracked black sea turtles in the Gulf of California and, the next summer, black bears in the Blue Ridge Mountains of North Carolina.  The fieldwork experiences were amazing and motivated me to go to graduate school to become an ecologist.

For my M.S. at Miami University, Ohio I move to a smaller and more manageable study species, white-footed mice, and examined how fragmentation of their forest habitat due to agriculture affected their population dynamics.  However, in the lab next door, friends of mine were studying the behavioral ecology of wolf spiders, including chemical communication, predator-prey interactions and mating behavior.  I soon became very interested in spiders and began my Ph.D. studying the ecology and evolution of sexual cannibalism.  I was interested in understanding why cannibalism was frequent in some species but rare in others.  Female hunger had an obvious and large role in predicting cannibalism but my work also suggested that nutrition may be important.

I then moved to Texas A&M University for a postdoc to study the role of food-for-protection mutualisms in facilitating the invasive success of red imported fire ants, Solenopsis invicta, in the Southern USA.  Due to differences in competitor communities, fire ants have greater access to mutualisms in their introduced range in the USA than their native range in Argentina.  As a consequence, fire ants in the USA consume more carbohydrates than fire ants in Argentina and these carbohydrates significantly increase fire ant colony growth even when insect prey are available ad libitum.

I continued with my interest in nutrition by moving to the University of Sydney to study the nutritional ecology of carnivores with Steve Simpson.  I’ve since been promoted to Lecturer and received an ARC Discovery Early Career Researcher Award.  Australia has an exciting diversity of insects and spiders and I’m looking forward to exploring and studying them further.

 3. How come that you became a scientist in ecology?

My interest in ecology and nature developed at a young age.  I grew up in the Northeastern USA and my family spent a lot of time camping, hiking, and fishing when I was young.  I also spent a lot of time flipping over rocks and searching in tide pools for insects, spiders, salamanders and crabs.  I would even occasionally feed the spiders that lived in the backyard.  Fortunately, my parents were very encouraging.

4. What do you do when you’re not working?

I enjoy camping, hiking, kayaking, and fishing.  Sydney has been a great place both for work and fun.  Although it’s a big city, it is surrounded by National Parks that are easily accessible and have a lot of beautiful trails through rainforests, mountains, and cliffs overlooking the ocean.

I also enjoy traveling both for research and fun.  Some of my recent highlights for research trips include traveling around northern Argentina studying ants and traveling to the Northern Territory of Australia to study araneophagic jumping spiders.  I’ve also recently traveled to Thailand and South Korea, both of which were a lot of fun.

Own website:

Posted by: oikosasa | November 8, 2012

How the aphids got their spots…

…is explained in Miroslav Kummel et al.’s new online paper “How the aphids got their spots: predation drives self-organization of aphid colonies in a patchy habitat”.

A short summary is given here by Miroslav:

Spatial self-organization is the ability of a system to develop a spatially heterogeneous distribution of population sizes across otherwise identical locations This self-organization can result in static areas of high and low population density across otherwise homogeneous underlying conditions. Alternatively it can result in traveling population waves, or in spatial deterministic chaos. Self-organization has emerged as a key concept in population ecology, because it can fundamentally alter the outcome and stability of interspecific interactions. It has been studied extensively theoretically, but there are very few empirical studies that establish the presence and causality of spatial self-organization in the field.

 In addition, the majority of current studies in spatial ecology (both empirical and theoretical) examine self-organization in laterally connected systems. These are systems where spatial effects are strongly determined by distance (e.g. the probability of colonization decreases with distance) and adjacency. However, space can be conceptualized in ways that are different. For example, space can be conceptualized as a network of connected patches, where the connections between patches are determined by other variables than pure distance. Human examples of such networks include a network of airports connected flights, natural examples include a collection of food patches connected by ant trails. The “network” conceptualization of space is very new to ecology and allows us to address previously intractable issues. Recent developments in network theory show that self-organization is possible in other network topologies such as random or scale-free networks.

In the field system that we study, foraging flights of coccinellid (ladybug) predators connect spatially discrete colonies of aphids into a network that has topology more complex than a laterally connected lattice. We show that predation by coccinellids induced self-organization in sessile aphid populations into small and large colony sizes on otherwise identical racemes of Yucca glauca that grew in close proximity to each other.

The self-organization was supported by a bi-modal frequency distribution of aphid colony sizes, and by the structure of density dependence that showed multiple attractors. The position of the attractors matched the position of the two modes in the bimodal distribution.

 We demonstrated that predation was the key driver of self-organization both empirically, and through a simple field-parameterized mathematical model. In the empirical study we showed that the multiple-attractor nature of density dependence disappeared when coccinellids were experimentally excluded from the system. The simple field-parameterized mathematical model showed that the multiple attractor structure was likely a consequence of the distribution of coccinellids among the aphid colonies: coccinellid number increased as a power (less than one) of aphid colony size. Thus the self-organization likely originated from spatial foraging decisions of the coccinellids.

The nature of self-organization in our system resembles that which was found in mathematical models of more complex networks. Thus our study provides the first link between these recent theoretical developments and field ecology.

Posted by: oikosasa | November 7, 2012

New pollination network model

In the new paper “Adaptive foraging allows the maintenance of biodiversity of pollination networks” Fernanda S. Valdovinos and her colleagues present a new population-dynamics model for plant-pollinator interactions:

 Here’s Fernanda’s summary of the model: One of the main novelties of our work is the new model of mutualistic networks that we proposed. Our model includes the trophic dimension of mutualistic interactions, by incorporating a separated equation for the dynamics of the resources that plant species offer to their animal visitants. In this way we could incorporate to the analysis of mutualistic networks the next biologically important process: 1) the production and animal consumption rates of plant rewards, 2) the competition and/or facilitation among plants via shared pollen/seed animal vectors, 3) the competition among animals for plant rewards, and 4) the animals’ allocation of foraging efforts. These processes were neglected by the traditionally used models on mutualistic networks, which simply represent mutualistic relationships as phenomenological positive effects among species. I think that these four processes may affect the interplay of network structure and dynamics that some studies have documented during the last years, like are the effects of nestedness, connectance and richness on the species persistence of those networks.

Posted by: oikosasa | November 6, 2012

Per Brink award winner 2013

We are very happy to congratulate Dr. Sharon Strauss, University of California, to being the winner of the Per Brink award 2013. Sharon will be awarded the Per Brink prize at the Oikos meeting in Linköping, Sweden in February 2013.

Here is a presentation of Sharon:

My research focuses on how organisms are influenced both ecologically and evolutionarily by the complex communities in which they are embedded, and by the inextricable interrelationship between ecology and evolution. The ecology of organisms reflects their long-term evolutionary history, with all its contingencies. The extent to which related species share and diverge in ecologically important traits, and how this shared ancestry affects community assembly is a growing area within ecology.  In addition, ecological dynamics and community assembly are influenced by microevolutionary change.  Ecological communities and abiotic environments exert selection on organisms; evolution in response to such selection, under the constraints of long-term evolutionary history, often results in populations that differ in traits from the parental generation. These different trait values, in turn, can feed back to affect the ecology of a system.

We can often predict how systems will respond under simplified conditions or when one ecological force is clearly dominant. For example, application of pesticides has consistently resulted in the evolution of resistance in insect pests (more than 300 spp.). When interactions are variable in space or time,  interactive in their effects on fitness, and when the selective effects of different agents are somewhat comparable in strength– as they are in complex communities– then our ability to predict how or whether traits will evolve, and how populations and communities respond through time, becomes much more of a challenge. As counterexamples, the ecology of introduced species, and the selective effects of  human actions that overwhelm other agents of selection on natural populations both represent useful, more simplified, contexts in which to explore the implications of natural community complexity.

The Per Brinck Oikos Award recognizes extraordinary and important contributions to the science of ecology. Particular emphasis is given to scientific work aimed at synthesis that has lead to novel and original research in unexplorered or neglected fields, or to bridging gaps between ecological disciplines. Such achievements typically require theoretical innovation and development as well as imaginative observational or experimental work, all of which will be valid grounds for recognition.

The /Per Brinck Oikos Award/ is delivered in honor of the Swedish ecologist Professor Per Brinck who has played an instrumental role for
the development and recognition of the science of ecology in the Nordic countries, especially as serving as the Editor-in-Chief for Oikos for many years.

The award is delivered annually and the laureate receives a modest prize sum (currently €1500), a diploma and a Swedish artisan glassware.
The prize ceremony is hosted by the Swedish Oikos Society. The award is sponsored by the Per Brinck Foundation at the editorial office of the journal Oikos and Wiley/Blackwell Publishing.

Posted by: oikosasa | November 5, 2012

Jessica Abbott – new SE

We are very happy to welcome Dr. Jessica Abbott as new Subject Editor for Oikos. And of course, we want to know more about Jessica so:

Jessica, what is your research about?

At the moment my main research focus is on how sexual antagonism influences an organism’s genetic architecture.  Sexual antagonism is when the same trait has opposite fitness consequences in males and females.  Sexually antagonistic genes and traits are interesting because they may hold the key to one of the long-standing paradoxes in evolutionary biology: the maintenance of standing genetic variation.  When selection is strong and traits are heritable, it is expected that standing genetic variance for fitness should be rapidly depleted.  Yet this is not what we see when we look at natural populations.  Sexual antagonism may provide an answer since it means that the fitness of any given allele is context-dependent, preventing rapid depletion of genetic variance.  I’m currently working on testing the hypothesis that sexual antagonism on the sex chromosomes maintains standing genetic variation across the genome, using two model systems: the fruit fly Drosophila melanogaster and the hermaphroditic flatworm Macrostomum lignano.

Can you shortly describe your career?

I am originally from Canada, and started my undergraduate degree at the University of Guelph.  During my third undergraduate year I came to Lund University as part of an international exchange program.  I liked it so much that I wanted to stay longer, and ended up living there for 8 years while completing a Master’s and and a PhD on female-limited colour polymorphism in the damselfly Ischnura elegans, under the supervision of Erik Svensson.  One of the female morphs is a male mimic, which benefits from reduced male mating harassment. This led me to become interested in sexual conflict in general, and in constraints on the evolution of sexual dimorphism and intralocus sexual conflict and sexual antagonism in particular.  In 2007 I therefore moved back to Canada on a Swedish Research Council-funded postdoc with Adam Chippindale at Queen’s University in Kingston.  It was there that I started working on sexual antagonism in fruit flies, using an established set of populations that had experienced male-limited experimental evolution for many generations.  In November 2009 I moved back to Sweden to join Ted Morrow’s lab at Uppsala University.  While there I carried out an investigation of my own set of experimental evolution populations, this time lines that had experienced male-limited X-chromosome evolution.  In 2011 I started a collaboration with Klaus Reinhardt from the University of Tübingen, on genotype-by-environment effects on sperm traits.  I started working in Lund again in February 2012, after receiving a Junior Researcher Project Grant from the Swedish Research Council, which has enabled me to set up my own independent lab.

How do you feel about becoming a subject editor at Oikos?

I’m excited about becoming a subject editor at Oikos.  I’ve been very active so far as a reviewer, both for established journals and within the new initiative Peerage of Science, but I’ve never worked as an editor before.  I’m looking forward to seeing the peer review process from the other side.

What do you do when not working?

I have two young daughters, so when I’m not working I mostly spend time with my family.  I love to read, so that’s what I do when I can find time just for myself.  Even though I’m busy I usually manage to finish a book once every couple of weeks.
Even more curious on Jessica? Visit her websites:

Institutional website:
Own website:

Posted by: oikosasa | November 2, 2012

Exotic invaders are modified by natives

Alien, invasive species are an increasing threat to biodiversity. In their paper “Competitive outcomes between two exotic invaders are modified by direct and indirect effects of a native conifer”, Kerry Metlen and co-workers has studied what two invasive species – a grass and a herb – and how they are affected by a native pine. Here, Kerry gives a short background to their study:

This research was inspired by a very striking pattern observable at undisturbed sites in the intermountain grasslands of western Montana, USA; Centaurea stoebe is supremely dominant in open prairie but virtually absent under the canopies of large ponderosa pines growing in the grassland.  At disturbed sites, any component of the native vegetation has been removed, C. stoebe appears to then move in aggressively, suggesting that some complex interaction among species drives this very simple pattern. 

 Extensive field observations confirmed the pattern that had seemed so obvious, as at this site just east of Hamilton, Montana, USA.  Germination experiments and extensive litter manipulation – in the field and in the greenhouse gradually allowed us to tease apart these complex interactions.  This fantastic adventure, lead us to discover that direct effects between species were insufficient to explain patterns of invasion of C. stoebe and Bromus tectorum and that shifting interactions among species gave a more complete picture of this dynamic plant community.

Posted by: oikosasa | November 1, 2012

Don’t forget to laugh…

Humour is an important creativity booster. And science can be oh so serious sometimes.

Check out this site when you need to laugh…

And don’t ever believe that we editors, at various stages, are lacking empathy or an understanding of the consequences of our decisions and messages:

This is the result, we know:

Or this:

Posted by: oikosasa | October 30, 2012

Battlefield study: Grasshoppers vs. wolf spiders

That predator-prey interactions can be temperature-dependent is something that Angela Laws and Anthony Joern shows in the new Early View paper in Oikos “Predator–prey interactions in a grassland food chain vary with temperature and food quality”

Read their background story here:

“Grasshoppers are important components of most grassland ecosystems.  These abundant herbivores can influence many ecosystem processes such as nutrient cycling and primary productivity.  But the effects of grasshoppers on ecosystem processes often depend on the outcome of their interactions with other species, including predators.  For example, spiders are common predators of grasshoppers that alter grasshopper behavior and can limit grasshopper population size. But the outcome of species interactions can be sensitive to changes in many biotic and abiotic environmental factors.

We were interested in learning how temperature can influence predator-prey interactions between grasshoppers and wolf spiders.  Ectothermic organisms like grasshoppers and spiders are likely to be especially impacted by shifting temperatures, because temperature affects many physiological processes including feeding, activity, and digestion.  But temperature may also alter species interactions with effects on food web functioning.  In our system, grasshoppers prefer warm temperatures and are active during the day while wolf spiders prefer cooler temperatures and are crepuscular.  Therefore, we predicted that shifting temperatures can alter predator effects on grasshoppers by expanding (through cooling) or contracting (through warming) the total amount of time each day that both grasshoppers and wolf spiders are active.

We conducted a three-year field experiment to test these predictions using common species of grasshopper (Orphulella speciosa) and wolf spider (Rabidosa rabida). We set up field cages and stocked them with grasshoppers only or grasshoppers and spiders.  To alter temperature, we surrounded some of the cages with temperature chambers constructed of steel frames covered with shade cloth (decreased temperatures) or with plastic sheeting (increased temperatures).  Other cages were left uncovered as a control.  The roofs of these temperature chambers were mounted on garage door tracks and could be opened and closed.  The roofs only covered the cages during the morning and were left open for most of the day.

We found that spiders had strongest effects on grasshopper survival in the cooled treatments, and weakest effects on grasshopper survival in the warmed treatments, as predicted.  In some years, this led to the appearance of a trophic cascade (an indirect effect of predators, where predator presence leads to an increase in plant biomass) in cooled treatments, but not warmed treatments.   Our results show that the outcome of predator-prey interactions between grasshoppers and wolf spiders, and their effects on plant production, can shift with temperature.  Our data also suggest that wolf spiders may be less effective at limiting the size of some grasshopper populations under warmer conditions.”

Posted by: oikosasa | October 29, 2012

How Google affects biodiversity

Is there really a connection between biodiversity and conservation and Internet? Oh, yes, read Michal Zmihorski and his colleagues new Early View paper in Oikos, Ecological correlates of the popularity of birds and butterflies in Internet information resources”.

Below, Michal tells us what made him and his co-workers to do this analyses:

“The idea concerning wildlife in the Internet resulted from a simple observation. Namely, we noted that different species are popular in the Internet whereas others are relatively rare. For each query Google provides the number of web pages containing the searched word(s) (here the name of a bird or butterfly). Consequently, we searched for possible mechanisms explaining the differences. More specifically, we expected that the patterns of popularity and rarity in the web were not random and should be somehow linked to the phenotype of particular species. Therefore we selected some basic characteristics of species, such as body size or migratory behaviour, and checked their importance in explaining the popularity on the internet. We excluded species whose names had more than one meaning. Initially we worked on Polish names of Polish birds but, following editors’ advice, we extended this to English names of British butterflies.


Several characteristics related to ecology and morphology of species were associated with their popularity in society. This in turn may have some obvious consequences for selection of species for conservation actions (e.g. as flagship species). We suggest that conservationists may use some phenotypic features of species in a more systematic manner to select for flagship species. However, to be honest, this is not of primary interest to us. The most exciting aspects of the association between phenotype and popularity is related to possible feedback, i.e. profits that popularity brings to a given species. First of all, we showed that there is some filtering of “colonization” of the internet by birds and butterflies (some features make species more effective in this “colonization” process). Secondly, the assumption that popularity in society is profitable for species seems to be true and may be related to the fact that organisms which are commonly known and well recognized by peoples may benefit from e.g. artificial feeding, nest-boxes, nest protection from predation and devastation, conservation actions, effective fund raising and so on (it is not easy to find references confirming this assumption, fortunately, we do not have to provide any in text for an Oikos blog!). If this is so the following mechanism can be proposed: the phenotypic features that makes a species popular in the Internet may also affect its fitness (because species that are popular in society may benefit from their popularity). Of course, the proposed mechanism has several weak points and needs to be confirmed, but in our opinion may be a catalyst for further studies. What is important is that if the mechanism works this means that natural selection may partially go through the virtual world of the internet, and such an idea is something new.

            All your comments and suggestions (including proposals for cooperation) concerning the topic of our study are highly welcomed. You have full text access to this content

Posted by: oikosasa | October 26, 2012

Relatedness and colonisation

How close to a relative should one settle? David Aguirre et al have shown that relatedness has an effect on colonization and settlement in some species, at least.

Here’s David’s summary of the paper that is now on Early View in Oikos:

“In organisms with sessile adults (e.g. many plants and marine invertebrates) variation in the density of colonisers is known to have a profound influence on the structure of populations and communities. Recent studies also indicate that the relatedness among interacting adults can be an important driver of differences in ecological performance among populations. Thus, it is surprising that few studies have examined the effects of relatedness on the non-adult life-history stages, and thereby the effects of relatedness on colonisation processes. In our study we bridged the gap between these two lines of ecological enquiry, and found that the effects of relatedness on colonisation differed in direction and magnitude in four sessile marine invertebrates.”

Posted by: oikosasa | October 25, 2012

On architecture and moose populations

In the new Oikos paper (now on Early View), “Simulated responses of moose populations to browsing-induced changes in plant architecture and forage production”, John Pastor and Nathan R. de Jager present a model examining how tree crown architecture affects moose populations. Here, they give a background to the study:

In the recently published paper, “Simulated responses of moose populations to browsing-induced changes in plant architecture and forage production”, we report the results from a model we developed nearly a decade ago as part of Nate’s Master’s thesis at the University of Minnesota-Duluth. The model examines the feedback effects of moose browsing-induced changes in plant architecture on moose population dynamics. We were able to construct the model because of a very well thought out and executed experiment in northern coastal Sweden (Persson et al. 2005 a, b). Inga-Lill Persson and her colleagues  annually removed plant tissue from study plots in proportion to different moose population densities and also added corresponding amounts of urine and fecal material. By measuring the architectural responses of different tree species to simulated moose densities (De Jager and Pastor 2008, 2010) we were able to ask a very simple question: Can the forage produced by trees that have been previously browsed in proportion to known moose densities support the same moose population densities over the long-term? Our main finding of the field study was that some properties of the crown architecture of deciduous trees, such as fractal dimension and twig density, responded quadratically to increased moose population density. At intermediate moose densities, these properties more than compensate for reductions in twig size, leading to small increases in forage production.

Our approach to constructing the model was extremely simple, assembling these equations for the architectural responses of plants to known moose population densities and the winter food requirements of moose, but ignoring other known factors that influence moose population dynamics (e.g. animal feeding rates, population demographics) and other known effects of moose on ecosystems (e.g. changes in soil fertility). The point was to see if these architectural responses in isolation could in principle determine moose population densities and dynamics. In fact, it was the simplicity of the model that kept us from submitting it as a manuscript for several years. John developed a renewed interest in the model after receiving positive comments from colleagues in Sweden following a presentation in  2010. Indeed, the editorial reviewers at Oikos liked the model and our paper because of its simplicity, not in spite of it.

It turns out that the architectural responses of plants that we measured can produce realistic moose population densities for northern Sweden  (an average of ~10-15 moose/1000 ha). But these population densities were only sustainable at the sites with the highest productivity and with species compositions heavily weighted toward deciduous trees, which can overcompensate for lost tissue due to moose browsing.  One of the new things we found was the quadratic responses of plant architecture to moose population density, especially those of birch, produced oscillations in moose populations on highly productive sites. The lessons we learned from this model were, first, that architectural responses of plant crowns to browsing may play a more important role in regulating moose population density than previously suspected and, second, that these architectural responses might cause complex population dynamics such as population cycles.”

Link to Persson et al. 2005 a

Link to Persson et al. 2005 b

Link to De Jager and Pastor 2008

Link to De Jager and Pastor 2010

Posted by: oikosasa | October 24, 2012

Secrets of Nobel Prize winner

Recently, the Noble prize laureates for 2012 were presented. But what is it that turns these researchers into Nobel prize winners? What are the key factors that makes the difference between a winner and the average researcher?

My interest for thistopic, stems from my concern that many university departments are not very good at providing the creative environment that I believe is required to house a coming Nobel prize winner. Constant stress, strong hierarchy, too heavy workload and a culture of criticism toward new ideas and suggestions rather than an open mind, are factors actively inhibiting creativity. But providing a creative environment is important for any department  and any research group that strives, maybe not for a Nobel prize, but to perform at the top international level and conduct novel research that might for example lead to a paradigm shift in their field. Innovative, novel research is key for Oikos as well, and it certainly requires a high dose of creativity.

Therefore, I was really curious when I found an article by Serge Haroche, co-winner of this years’ Noble prize in physics, The secrets of my prizewinning research, where he tries to explain what made him a Nobel Prize winner. He gives a lot of credit to the “unique intellectual and material environment of the Kastler Brossel Laboratory at the Ecole Normale Superieure in Paris”. At this lab, he got the opportunity “to gather a permanent research group of exceptional quality, transmitting expertise and knowledge accumulated over time to successive generations of bright students.

Other important factors he mentions are reliable financial support and European mobility programmes, “bringing expertise and scientific culture to complement our own” by opening up for visiting students and researchers. Specifically important, he argues, was “the freedom to choose our path without having to justify it with the promise of possible applications”.

Haroche also expresses an anxiety over the scarcity of resources and “the requirement to find scientific solutions to practical problems of health, energy and the environment”, that meet young scientists today. “I can only hope that they will be granted similar opportunities to those that we had: being free to choose research goals and to manage his own efforts over the long term, and able to afford the pursuit of hazardous paths before seeing the light.

What about you, do you work in an environment stimulating Noble prize research or at least innovative, novel research that will fit in Oikos?

Posted by: oikosasa | October 22, 2012

Well informed animal movement

In the paper “From random walks to informed movement”, Emanuel Fronhofer and colleagues present a model showing that with “memorized” spatial information, an animal will boost it’s foraging success, as compared to random walk. Now on Early View.

Read Emanuel’s story about the model:

When animals move they frequently search for resources. This may, for example, be a female butterfly searching for proper host plants, a gnu exploiting grassland, or a male dragonfly searching for mating partners. Being an efficient searcher is thus an ability of great fitness implications. Indeed, movement is so fundamental to life that research on animal movement is highly relevant for many basic and applied issues.

Up to now movement is mostly modeled as a random process (random walk) and it is fascinating that such models, like the “Lévy walk”, are so capable in grasping the statistical attributes of animal movement. Yet, if we want to predict the influence of man made modifications of landscape structure on foraging success or the implications of global climatic change on animal dispersal we need a thorough understanding of the mechanisms governing movement decisions. Evidently, movement is controlled by an animal’s perception, memory, and its ability to infer the likely position of resource based on general knowledge about landscape attributes and the specific information at its hand. Further, animals should also be able to think more than one step ahead (anticipation), i.e. foresee future consequences of its moves.

Here we propose a model that accounts for all these elements (perception, memory, inference and anticipation). Our analysis shows that even a very basic implementation of these processes allows an enormous increase in foraging efficiency and results in movement patterns typical for systematic search within resource patches (e.g. of flowers of food plants; fig.1), straight movement between such patches (fig. 1) and even the emergence of foray loops (fig. 2) that have been observed in e.g. butterflies.

Our model is easily applied to insects like butterflies, wasps, or flies, searching for food or suitable plants to lay their eggs. The analysis of this model highlights the strength of mechanistic approaches to movement modeling and sets the stage for the development of more sophisticated models of perception and memory use invoked in movement decisions and dispersal. 


Posted by: oikosasa | October 19, 2012

What shapes the personality?

Oh, yes, fish have personalities as well! Matthew Edenbrow and his colleague has digged deeper into this to unravel the basis behind it. Now on early View: “Environmental and genetic effects shape the development of personality traits in the mangrove killifish Kryptolebias marmoratus”

Here’s Matthew’s own story:

Personality is defined as individual consistency in behaviour over time or situations. In humans it is obvious that we all differ in our personalities with some individuals being risk takers or bolder than others. While personality is clearly part of what it means to be human, there is considerable evidence suggesting that these traits are also exhibited throughout the animal kingdom. In particular, personality has been documented in several animal groups including primates, reptiles, fish and even insects, suggesting that personality is not only important but that it evolved early. At present, however, we have little insight into what factors determine individual differences in personality. Research suggests that experiences of different environments during development may underpin personality variation. In addition, growth as well as age at sexual maturity may also be important; with fast growth/early maturity suggested to generate bolder personalities. In this study we used the naturally “clonal” mangrove killifish (Kryptolebias marmoratus) as our study organism. This species is exciting because it permits us to investigate how genetically identical individuals adjust behaviour, growth and reproductive development depending upon the environment experienced. In this study we reared several genetically identical individuals in three rearing environments: 1) the presence of siblings, 2) reduced food and 3) simulated predation risk. We then investigated growth and three personality traits: exploration, boldness, and aggression, at three stages of development. Our results indicate that only individuals exposed to simulated predation risk exhibited behaviour consistency, suggesting that risk perception during early life stages is likely to be important in personality development. In addition, each of our rearing environments resulted in different growth rates and age at sexual maturity yet these differences were not key drivers of the resulting behavioural differences we observed

Posted by: oikosasa | October 17, 2012

Fruit-frugivore interactions not that simple after all…

Now online: Perea et al. “Context-dependent fruit-frugivore interactions: partner identities and spatio-temporal variations”

Here Ramon Perea summarizes the study:

Plants are able to use animals as vectors for the dispersal of their seeds. Many fleshy fruits constitute a food attractive for different vertebrate species, that usually ingest jointly the edible pulp and the seeds, which are later defecated or brought up in suitable conditions for germination. Studies on this kind of plant-animal mutualism, called endozoochory, are numerous, but usually refer to only one pair of mutualists, or are made during one fruiting season or at only one place.

Does seed dispersal by mammals depend on the spatio-temporal context in which the interaction takes place? For instance, species abundances, specific seed crops, availability of alternative foods or vegetation structure usually change from year to year or from one habitat to another at the same locality. Many of these changing factors might affect important attributes of the plant-animal interaction. In our particular case of seed dispersal, the environmental context might modify, for example, the quantity of seeds dispersed (interaction strength) or the quality of dispersal (seed treatment, deposition on suitable sites for germination and survival, etc.), which could eventually alter the so-called sign of the interaction (from a highly successful dispersal –mutualism- to a highly unsuccessful dispersal –antagonism).

Our field work was performed in the Doñana National Park (SW Spain), under Mediterranean conditions, where we collected about 1600 faeces of a whole assemblage of fruit-eating mammals (frugivores: red fox, badger, red deer, wildboar and rabbit).  About 300,000 seeds of fruit-bearing plants were recovered of these faeces, measuring frequency of seed occurrence, plant species and seed damage for three different habitats.

For each particular fruit-frugivore pair, the interaction strength largely varied with the spatio-temporal context (year and habitat) at our local scale, leading to a low specificity across the seed-frugivore network. Frugivory and potential endozoochory should not be simply considered a mutualism leading to successful seed dispersal, but a rather variable relationship along the mutualism-antagonism continuum, depending on the ecological context.

Posted by: oikosasa | October 16, 2012

Evolution in cave amphipods

First author Cene Fiser gives a short version of their paper Coevolution of life history traits and morphology in female subterranean amphipods“. 

Fine-tuning evolution often requires compromises. Maximizing female’s fitness by optimization egg number and egg size to the environmental demands is a classic trade-off in evolutionary biology. But, can co-evolving morphological changes affect or even avoid this trade-off? We compared Niphargus species found in springs and in deep caves and showed that cave species are larger, stouter, have larger eggs, yet the number of eggs is not lower compared to spring species. These changes seem to be a result of decreased fluctuations of abiotic factors and of decrease in food availability in deep caves compared to springs. The environmental gradient most likely presents major source of selection that affected all herein studied morphological and life history traits. However, we have shown that the co-evolution of biological traits can modify the otherwise expected outcome of selection. We suggest that increased body size, that also enables storage of more energy, enables allocation of additional nutrients in egg size, yet the number of eggs can remain the same. Additionally, as larger eggs require better supply with water for aeration, bigger species have also modified body shape.


Posted by: oikosasa | October 15, 2012

Double trouble in paradise

In the study “Density- and trait-mediated top–down effects modify bottom–up control of a highly endemic tropical aquatic food web” Christopher Dalton and co-workers have looked at bottom-up and top-down effects in anchialine ponds on Hawaii. Here’s Chrsitopher’s own story about the study:

For centuries, early Hawaiian residents divided land on the island into expansive parcels known as ahupuaʻa, with each ahupuaʻa containing all of the resources the residents would need to survive (water, food, shelter). Ahupuaʻa typically ran in radial lines extending from the top of the nearest volcano (Mauka; near the mountains) to the shore of the ocean (Makai; near the ocean). The expression Mauka to Makai lives on as an important model for island conservation today, emphasizing that the spectacular and unique biodiversity of these islands cannot be preserved without understanding the links between ecosystems.

Perhaps no single Hawaiian ecosystem better reflects the necessity of landscape-scale conservation as the anchialine ponds of coastal Hawaiʻi, connected through porous lava substrate to both tidal seawater and fresh groundwater. One of the most striking organism in the ponds is the endemic atyid shrimp, Halocaridina rubra (locally known as ōpaeʻula, or red shrimp).  This locally abundant invertebrate shows diel migration between daytime refuges in subterranean environments and nighttime foraging in productive surface habitats. In anchialine pools, the grazing of ōpaeʻula is often attributed a keystone function for maintaining a diverse and tuft-like epilithic crust of algae, cyanobacteria and heterotrophic bacteria.

We assess the roles of nutrients and invertebrate consumers in anchialine pond food webs by taking advantage of long-term, whole-ecosystem anthropogenic modification of bottom-up (nutrient enrichment) and top-down (grazing) controls. This study provides insight at the ecosystem scale for the interactions between top-down and bottom-up control in a system of dire need of information to direct management practices against threats from development and invasive species.

We collected quantitative samples of the epilithon quantity and composition, the abundance (day and night) of ōpaeʻula, the presence of fish and the dissolved nutrient concentrations. Sometimes this meant getting wet in the deepest pools, and sometimes it meant wading through algal and detrital mats up to half a meter deep. In the end, we captured a snapshot of the relatively simple food web structure and nutrient availability of twenty pools.

This study provides whole-ecosystem scale insight into the relative influence of bottom-up and both trait and density mediated top-down effects in pool food webs, and it also provides evidence to help guide management decisions. Our research suggests the ecological benefits of mitigating nutrient pollution are comparable to those of removing predatory, invasive fish, and monitoring these two factors can prevent the dramatic ecological change we observed in high nutrient ponds with fish.

Ultimately, preservation of Hawaiian anchialine ponds requires a perspective beyond the edges of these ecosystems. The nutrient enrichment that we observed in anchialine ponds was associated with land use (resorts, hotels and golf courses) immediately surrounding those ponds.

To truly understand and protect these hotbeds of endemism into the future, however, research must look from Mauka to Makai and assess the role of landscape context in driving change in these unique ecosystems.

Posted by: oikosasa | October 12, 2012

Mistletoe network

Isn’t it often so that the most brilliant ideas come to us when our brains are “on holiday”, thinking of something completely different. That was the case for Ray Blick. The idea of studying networks among mistletoes and their hosts, that came during along train journey across Australia, has now resulted in a paper in Oikos, that is now online: Dominant network interactions are not correlated with resource availability: a case study using mistletoe host interactions” by Blick et al. Ray describes what happened:

All field scientists have their peculiarities. Botanists are typically found near their transportation, unable to get past nearby plants. Ornithologist can be found walking with their eyes closed and their ear to the wind (somehow avoiding all objects in their path). And Ecologists have a spectacular ability to chop-and-change direction like a drunken person driving a car at night. I fall into the last category, where slight ‘abnormalities’ in tree shape or colour will draw my attention – Mistletoe?


The idea for this research originated during a ‘forced’ 1100 km train-line transect on a 16 hour journey from Sydney to Broken Hill, New South Wales, Australia. During this time the train followed a precipitation gradient traversing urban/city parks, temperate and subtropical rainforests, a wheat belt, closed Eucalypt woodlands and finally open, inconsistent sclerophyllous vegetation. All of which contained a range of mistletoe species.


Unable to ‘chop-and-change’ from my N = 1, ocular sampling, holiday fixed-distance, train-line transect, with an expected sleep-deprived error bias, I became interested in testing the idea that the structure of an ecological community did not have to depend on commonness. The current manuscript addresses whether host-availability, or dominance, is an important factor structuring an ecological network between a parasite and its host.    

Posted by: oikosasa | October 11, 2012

Understanding fox demography

One of the new papers online in Oikos is about the importance of full understanding of demography of wild populations for management programs. One of the authors, Eleanor Devenish-Nelson gives us here the background to the study Demography of a carnivore, the red fox, Vulpes vulpes: what have we learnt from 70 years of published studies?”:

The successful management of wildlife depends on the ability to predict the consequences of management actions. That, in turn, often requires a good knowledge of a species’ demography and dynamics. We can use that knowledge, of issues such as birth and death rates, to produce predictive models with which we can simulate different management strategies. In situations in which we don’t know enough about a population of interest, it is common to use ‘surrogate data’ (demographic parameters from other populations of the same, or closely related, species) in order to construct predictive models.

    One species of considerable management concern is the red fox. Red foxes are widely hunted and are important hosts for several diseases. The management of red foxes is often contentious, invoking strong feelings in many people. We wanted to produce what we thought would be a straightforward model of red fox dynamics, as the foundation for answering several applied questions. At first glance, foxes appear to be well studied: a quick search brings up over 1000 papers on aspects of their demography. However, an initial assessment of that literature revealed that the demography of this widespread species was surprisingly poorly known, with limited data for most populations and, even for several better-studied populations, missing information on birth or death rates. Some of the demographic rates that we collated were highly variable between populations – but was this a result of genuine differences, or of poorly defined or presented data?

            Although the available data on red fox populations are often uncertain and frequently based on relatively short-term studies, we were able to analyse the demography of eight different populations. Those analyses revealed considerable variation in demography among the populations. Differences were sufficient to be of consequence for management. More importantly, by substituting demographic parameters between fox populations, we showed that using surrogate data could often be very misleading for managers. Data substitution is often a necessity but our analyses suggest that it can guide how managers prioritise measuring demographic parameters for their focal populations. In general, for example, a model using surrogate data on the probability with which females breed will be more misleading than if surrogate data on litter size is used. Hence, managers should prioritise accurate estimates of the former.

            Overall, what started out as a simple study revealed the significant gaps in our understanding of fox demography, especially in relation to the selection pressures this species faces, such as hunting, disease and a highly variable climate across its range. Owing to variability between populations and the dangers of using surrogate data, the need for more widespread, long-term monitoring is clear. Emerging technologies should be harnessed to make routine the widespread collection of demographic data on wildlife populations. This paper emphasises why a better understanding of the demography of fox populations is of relevance for management. 

Photo  © Paul Cecil

Posted by: oikosasa | October 10, 2012

Hello – are you out there? On detectability and abundance

In the new Early View paper  The influence of abundance on detectability” McCarthy and co-workers explore the relationship between actually being detected and being there.

Here is Michael McCarthy’s own story on the study, the paper and the results:

How hard do we need to look to be sure a species is absent when it is not detected? This question is fundamental in ecology. It is relevant when determining the appropriate level of survey effort, when compiling lists of species, when determining the extinction of species, and when developing surveillance strategies for invasive species.

Without sufficient survey effort, species are not detected perfectly. Imperfect detection arises because species may be temporarily absent, hidden from view, or simply require extra effort to find. The detectability of species can be defined by the rate at which individuals of a species (or groups of those individuals) are encountered.

Detectability of species will increase with abundance, all else being equal. But what is the nature of that relationship? We present a model of this relationship, with the rate of detection being a power function of abundance (Fig. 1). The exponent for this function (b) will equal 1 if individuals are encountered independently of one another. When clustering of individuals increases with abundance, we expect this exponent to be less than 1, but greater than 0.

As values for the scaling exponent approach 0, the detection rate becomes less sensitive to abundance (Fig. 1). Knowing how detection rate scales with abundance can assist when determining detection rates of rare species. This is important because detecting rare species is often important, yet estimates of detection rate are often most uncertain for these species. A scaling relationship would allow extrapolation of detection rates to cases when species are rare.

The field trials were conducted in a remnant of eucalypt woodland in Royal Park near The University of Melbourne searching for plants and coins, in an exotic grassland in Royal Park searching for planted Australian native species, and in eastern Australian forests searching for frogs.

Posted by: oikosasa | October 9, 2012

On the beauty of beta diversity

Recently published in Oikos online is the paper by Carvalho et al. “Measuring fractions of beta diversity and their relationships to nestedness: a theoretical and empirical comparison of novel approaches”. Here, José Carvalho gives us the background and a summary of the paper:
Paul Jaccard proposed the well known Jaccard index of similarity in 1901. Since then the index has been used, in its (dis)similarity forms, widely by ecologists, notably in beta diversity studies. Beta diversity is one of the most broadest concepts in ecology, leading to multiple interpretations, meanings and discussions. This is probably the reason why ecologists took over more than 100 years to discover that the Jaccard index can be decomposed into two sound components of dissimilarity, replacement (turnover) and richness differences. Interestingly, after such a long time, two teams arrived independently to the same conclusions. This work represents the unification of the efforts made by the authors of both teams to elucidate others about the advantages of this approach in understanding the processes that originate beta diversity. However, the proposed decomposition is, indeed, much more general than a simple partitioning of a beta diversity measure, and applications in other fields may be expected. The generality of this approach comes from the fact that it may be viewed as the natural decomposition of a contingency table into two asymmetric components, representing the substitution of units (replacement) and differences in the number of units (richness differences).
Therefore, there is an intrinsic beauty in this approach, which comes from its generality, deep significance and remarkable simplicity.
Posted by: oikosasa | October 5, 2012

Future h-index?

Too much h-index around? Number of citations, h-index and journal’s impact factors are easily used statistics in evaluations of applications for academic jobs and fundings. Easy – yes. But appropriate – not really. One of our editors, Stefano Allesina (University of Chicago), has –together with two colleagues– suggested an alternative metric to use in evaluations: Future h-index, based on scientific activities, diversity of journals where papers are published, network etc. Their method was recently published in Nature.
Stefano, is this the future for academic evaluation committees?
When I am sitting on hiring committees, I often think: “is it even possible to determine which candidates are going to be good scientists by just looking at their CVs?” To answer the question, we analyzed the career of hundreds of neuroscientists. It turns out that yes, you can pretty much forecast their future impact (i.e., predict their future h-index) using exclusively information that is contained in their CVs. What I think it’s good news is that the variables with the strongest exploratory power are basically those you would have thought they should be: current h-index, number of publications, number of publications in top journals. However, we find that the diversity of journals (and hence the size of the “audience”) is also very important. Thus, I think hiring committees should also evaluate the potential candidates for their ability to reach scientists outside their disciplines and main field of interest.
What response have you met on your method?
-There is definitely some interest, as this work adds to the heated debate on how to measure productivity in academia. However, I see the contribution as a way to skew the debate from past accomplishments toward future achievements. If anything, concentrating on the past tends to promote very conservative science, while what we need is innovation.
Isn’t this just what evaluators actually are considering, but in a non-statistical way?
-Definitely. In a way, you can read the results by saying that “science works”: what we’re telling our students to focus on — good publications — is really what matters. However, I think the emphasis on the diversity of audiences is something that is not normally fully considered by committees and funding agencies.
Can the method be used to calculate future Impact factor for journals as well?
-We found the method to be quite context-dependent. It works well on neuroscientists, when we model neuroscientists. However, the predictive power diminishes when we’re trying out-of-fit predictions in other fields. That said, I think that it could be possible to adapt the technique and extend it to journals.
Posted by: oikosasa | October 4, 2012

Allee effect – a matter of friendship

Suppose you don’t have enough friends around you to do well. Then a foe shows up and takes the place of a friend. What would happen? In our paper “Competition, facilitation and the Allee effect”,  we study the dynamics of two populations with Allee effect (you need a number of friends to do well). The two populations compete (are foes) but can functionally replace members of the other population for some aspects (take the place of a friend). For example, some plants experience an Allee effect because they cannot attract enough pollinators when rare. But a competing plant species can help. So what does happen? Can you imagine that you might be completely dependent on your foe – and they on you?

Frihjof Luscher (on picture)

Lutscher’s and Iljon’s paper is now on Early View in Oikos, read more here



Posted by: chrislortie | October 2, 2012

DataUp now live

No excuses now, you can archive your data directly from excel files. A real snap! Here’s the link, check it out. I will try it this week too. At this point, it does not seem to provide DOIs but maybe they will.

Perhaps we should encourage authors to archive Oikos datasets, once ms accepted, using this tool?

Apparently, they take babies too (pic from their site).

Posted by: oikosasa | October 2, 2012

Oikos now on facebook

Yihaa! Finally we’re on facebook as well! Like us and get updated on new hot Oikos papers online!


Posted by: oikosasa | September 28, 2012

It’s raining again…

Nothing can spoil a vacation as efficiently as a rainfall. And nothing affects a farmer’s mood as rain- it’s presence or it’s abscence. Too much or too litte. Always an issue worth of debating.

In one of the latest Early View papers in Oikos, “Seasonal, not annual precipitation drives community productivity across ecosystems”, Todd M. P. Robinson, and co-workers study the effects of precipitation on plant production in various ecosystems.

Below, the authors give a short background to the study:

While any farmer will tell you how important it is to receive rainfall at certain times of the year, many ecological plant studies focus on how total annual rainfall affects plant production. After a meeting for the US Long Term Ecological Research Network (LTER), a group of us decided to test just how helpful it would be to focus on shorter time scales by examining whether rainfall during either the beginning, middle, or end of the growing season correlated with total aboveground production during the same season. We found that focusing on the amount of rain across one or two short time periods usually gave as much or more information on plant production as annual rainfall amounts. This was generally true across a wide array of communities from desserts to forests, despite the large difference in vegetation types and total available water.

As a graduate student working group with members from multiple institutions, we supplemented our initial LTER funded workshop by using Skype and email to coordinate our analyses and writing. As young scientists, we are excited that our cross-site analysis can contribute to the development of a more nuanced approach to plant-rainfall interactions. We expect that the combination of our work with other advances in plant-water dynamics will improve our understanding of how current and future variation in precipitation will affect plant communities.


Posted by: oikosasa | September 20, 2012

Failure leads to success!

Last week I attended the conference ”Innovation in Mind” here in Lund. It’s not about technical innovations per se, but more about the creative process that might lead to technical innovations. Or groundbreaking research results. Or the brilliant idea that allows you to both help people and become rich yourself. Or solve the big life problem…or other things gaining from allowing creativity to flow.

One take-home message from the meeting was a reminder about the classic importance of failures. Professor Henri Petroski, at Duke University pointed out that failures lead to success just as success often leads to failures in a kind of cyclic manner. Without failures, no progress and development.

So remember, next time your manuscript is rejected you’re one step closer to a successful accept!

And, as Petroski also pointed out – success is a bad teacher, but a good motivator. Failure on the other hand might not be a very good motivator (easy to give up…) but a very good teacher!

Posted by: oikosasa | September 13, 2012

Gender bias in invited Nature papers

” fewer women than men are offered the career boost of invitation-only authorship in each of the two leading science journals”, states researcher Daniel Conley, from the Department of Geology in Lund.

Together with his colleague Johanna Stadmark he critices this gender bias in an article in Nature recently

I would be both very proud and very surprised if I could state that such discrimination does not occur at Oikos. But I’m afraid I can’t. Until recently we have however not invited researchers to write papers, so in that category of articles we dont’t have any large dataset to analyse.  I am rather convinced that our EiC for Forum papers (including some newly invited manuscripts), Dustin Marshall will be careful when inviting man after man after man in the future…

Are you convinced of your own unprejudiced mind? Check your prejudice status at this site. Many variants to choose between, but go for the most relevant one – gender and science! The test is about associations, not conscious decisions.

Posted by: chrislortie | September 12, 2012

Future impact: Predicting scientific success

Cool Nature paper on how to predict success.

Posted by: oikosasa | September 5, 2012

Lots of equations=few citations?

In the July issue of PNAS, Fawcett and Higginson argue, based on statistical analysis of citation rates, that a high density of equations will increase citation by theoreticians, but reduce citations by nontheoreticians even more. They advocate putting a minimum of equations in the main text, move everything else to the (online) appendix, and insert a maximum of verbal explanations of each equation.
This sounds trivial. Don’t we teach all our students to leave out unnecessary maths in presentations and manuscripts? Apparently this is easier said than done, as we still see very equation-rich papers in journals for the general ecological and evolutionary audience (such as Oikos). The reason may be that “necessity of equations” is subjective. For a thorough understanding, a full mathematical derivation seems indispensable, and hiding it from view by putting it in an appendix may also hide it from peer review. This may be good for the author (higher acceptance probability and more citations), but can be detrimental for science, and in the long run also for the author: there is nothing more terrifying for a theoretician than being confronted with an error in a derivation after publication, please let it be found during peer review!
Hence the theoretician faces a serious dilemma for which I have no full solution, only a couple of recommendations. To minimize errors, find collaborators that can check your derivations (so editors, be suspect of single author theoretical papers). A thorough verbal explanation of a model’s assumptions (and some of the derivation) may not only aid the reader, but may also advance the author’s own understanding of his/her work: when a theoretician has difficulty explaining what he/she is doing, the work is either unrealistic or incorrect. And, something Fawcett & Higginson did not analyse in detail, use simple equations: avoid Greek or curly symbols whenever possible, divide the equation in pieces where each piece has a clear meaning. Finally, when you’re really reluctant to banish your cherished formulas to an appendix, use a box. A box is really an inline appendix, and may represent the best of both worlds. Remember to think out of the box!

Rampal Etienne, SE Oikos

Posted by: oikosasa | August 28, 2012

Per Brink award lecture in the September issue

Each year, at the Oikos meeting, Oikos and Wiley/Blackwell together with the Per Brink Foundation, awards the Per Brink Oikos award in honor of Professor Per Brink. This year’s laureate, Prof. Tim Coulson from Imperial College London gives you below a short version of his paper entitled “Integral projections models, their construction and use in posing hypothesis in ecology”.

More about the award is found in the Editorial for the September issue 

At any point in their lives individual can be measured for a large number of characters.   These characters might be genotypes at a specific locus, age, body size, the ability to fight disease and behaviours.  Some characters might be continuous, some might be discrete.  Population level distributions of these characters can be constructed at each point in time.  Over time, a population level character distribution might change as individuals are born, die and develop.  Any population can consequently be considered as a temporally fluctuating character distribution.  Population biologists – be they life history theorists, quantitative geneticists, population geneticists or population ecologists – work with statistics that summarize aspects of the dynamics of character distributions.

Integral projection models provide a way of modeling the dynamics of character distributions.  Recently, a number of biologists including Steve Ellner, Mike Dixon, Mark Rees, Shripad Tuljapurkar, Dylan Childs, Jessica Metcalf, Peter Adler and I (to name a few), have worked on developing and applying integral projection models to address a number of questions in ecology, life history theory, micro-evolution and longer-term evolution.  A growing body of research has revealed that these models can be relatively easily parameterized for both observation and experimental laboratory and field studies, and that they can be analyzed to provide novel insight.  Given the utility of the models, many researchers, including me, believe that their use will increase in future.  For this reason I felt writing a paper showing how they can be constructed and used could be useful.  In the Per Brinck lecture I gave this year I described integral projection models, their parameterization and analysis.  The Oikos paper that accompanies this lecture develops this theme, and I hope it useful to researchers who want to learn how to construct and use integral projection models. I hope it proves of some use.

I was surprised, delighted and honoured to be awarded the 2012 Per Brinck award, and I’d like to thank the Oikos society for selecting me to receive it.  The Karlstad meeting of the Oikos society was one of the most enjoyable meetings I’ve been to, and I plan to attend many of these meetings in the future.  I do hope my paper generates some interest.


Posted by: oikosasa | August 19, 2012

Being a Subject Editor…

Why being a Subject Editor at Oikos? And what does it really mean? Wim van der Putten, who has been Subject Editor at Oikos for many years, and for several other journals as well, gives you his answers:

Why would you submit your research papers to Oikos and what would you expect to read in this journal? Those are key questions that each Subject Editor has to answer every time a new manuscript is ending up on the digital desk. Before that happens, however, the submitting authors had to answer the same questions, as did the Editor in Chief and the Managing Editor, and later on the anonymous referees. If somewhere in this chain a weak connection shows up, the submitted paper will not appear, at least not in Oikos. In spite of the high rejection rate at Oikos, my experience is that simply addressing these basic  why-what questions results in a balance between papers for which I proposed acceptance and rejection that comes close to the acceptance-rejection final rate of Oikos and official complaints are rare.

I am Subject Editor for Oikos since 2007. As in all journals that I was involved in as Subject, or Handling Editor, the atmosphere is nice, personal, involved, and, quite important, professional. The way how decisions are made may differ among journals. For example, in the case of the Journal of Applied Ecology, it was pivotal that the work presented should be both scientifically novel and practically applicable, which ruled out quite some submissions. On the other hand, in the case of Ecology Letters the question whether the paper presents excellent novel science that is of interest for a wide audience provides another sort of criterion and my experience is that reviewers often are quite outspoken on that issue.

My subject is terrestrial ecology, soil ecology, aboveground-belowground interactions, climate change and invasions. Quite wide and luckily I don’t get all papers in this area. All these papers get equal chance, provided that they are not narrowly focused. This may happen with for example soil ecological papers that are too obvious for specialists and not for a wider ecological audience. I think that Oikos is very suitable for soil ecological papers, provided that they are strongly conceptual. Those papers are, to my experience, very well cited in Oikos. Papers that deal with, for example, mesh sizes of soil sieving or a process in plant ecology that has already reported ten times, will not be sent out to reviewers. Also, papers that do not test clear hypotheses may not find their way through. Pleasantly, it is not too difficult to find referees, except in Summer or just before Christmas. I really don’t understand why authors submit their paper on the day before their Summer holyday starts. All potential referees may also be out for field work, hiking in the mountains, or whatsoever, which provides a hassle for the journals to find appropriate available referees.

Why would you be a Subject Editor? I see it this way. Progress in science depends on a peer review system and that depends on scientists who are willing to spend their time to handling and reviewing manuscripts for journals. When you wish to publish, but not to contribute to this process, you are capitalizing on time from others to keep the system running. That would be sort of cheating. I don’t get paid, so that my decisions will not depend on money, but on the question if I wish to make time available for this activity. The nice thing of being a Subject Editor is to send manuscripts out to who are the best experts in that field, ask their view and then weigh the outcomes. The difficulties are always in weighing contrasting views. It would be far more comfortable when all research would be published open access and I hope that we will gradually move towards that system, but there are many limitations and constraints as well.

For the near future, I hope that Oikos will be able to develop a strategy that facilitates easy availability of published work. It is very easy these days to send a request for a copy to the corresponding author, but that takes extra time and efforts, which is a real waste of money. Contents-wise, I think that Oikos is a great journal in the field of community ecology and that it might be developing even more profile into that area. Aboveground-belowground interactions and the rapidly developing area of analyzing the composition and functioning of networks in pristine ecosystems and those under (human-induced) global changes such as land use, climate change, and invasions are in my view perfect topics for Oikos and I hope to see some really great manuscripts in this area. I am ready for them!

Wim van der Putten

Here is a superb interview with Stephanie Hampton. She is the Deputy Director of NCEAS and one of the PIs on the DataOne project. Her talk at the esa 2012 meeting was very well received so I nabbed her for a chat.  The interview also includes suggestions for Oikos and journals in general. Also, she introduced me to some new terminology and thinking on the importance of data. I hope you enjoy it.

Posted by: chrislortie | August 17, 2012

Vibrant data: another example of novel synthesis

This project is cool, Eric Berlow is one of the founders and is an ecologist with publications on food webs, interactions, alpine meadows, and the marine intertidal. This new project is bring together big data, designers, and Intel researchers to model and understand the dadta ecosystem they inhabit. Click on the research part and you will see the scope of data. Similar to the Ocean Health Index post below, this is another really nice example of ecological principles blending with social data. Here, they are using collective human input and network analysis to identify a few ‘under-nourished’ Grand Challenges for democratizing data. Wow, how can we help?

Posted by: chrislortie | August 16, 2012

Ocean Health Index

This is definitely novel synthesis. Here is the link to a really fascinating index that integrates both human and environmental condition estimates to provide a composite score of ocean health. It is also organized by public goals such as food provision, carbon storage, and provides a score for each. Canada beats Norway, Finland, and Belgium. Here is the link to the full details in Nature and the news reports.

Posted by: cjlortie | August 11, 2012

Data samples & data abstracts alongside Oikos papers

I was wondering what ecofolks thought of this: Oikos publishing a small data sample alongside each paper (when authors provide). This could be as simple as a small txt file or flat sheet showing the data structure with a few reps. Of course, an eml or link to the full dataset is preferable and should also be there, but it might be nice to at least have a little preview right there we could click on. In addition to this, we could publish a small file describing the meta-data, formally or informally, and could include a list of all factors and responses measured. This would be so fascinating. I don’t see this as impediment to full and open access to data. This would be a journal-level contribution to the process. It is also a teaser for readers to get the community wanting to see more data.

Posted by: cjlortie | August 9, 2012

DataUp interview with Carly Strasser at ESA2012

Here’s a quick interview about DataUp and how authors and journals can participate.

Posted by: cjlortie | August 9, 2012

Opensci interview at ESA2012

Here’s a great interview from today at the esa about the open sci initiatives in eeb.

Posted by: oikosasa | August 7, 2012

Meet Oikos at ISBE in Lund in August!

The 14th International Behavioral Ecology Congress is held in Lund on August 12-17 2012. Oikos is represented at Wiley’s stand, and I will be around from time to time.

If you have questions about Oikos or issues you’d like to discuss with me, send a mail and we’ll set up a meeting.

Mail to

Hope to se you in Lund!

Åsa Langefors

Managing Editor

Posted by: oikosasa | July 31, 2012

Inspiration from Tallinn

A couple of weeks ago, the Oikos Editorial Office attended the conference “Editing in the Digital World”, organized by EASE (European Association for Science Editors) in Tallinn. Apart form giving us the opportunity to explore the midevial Estonian capital, it provided us with some really productive and creative inspiration.

It was especially two plenary talks that got us going on the new digital editing world. First, Deborah Khan from BioMedCentral, London talked about “Open Access and Digital Models”. We are heading there. Sooner or later. To Open Access. Yes, Oikos as well. The questions are just how and when? Deborah made it sound much easier than we had conisdered before, giving some answers to those questions. The answer to the second question is now: A bit sooner that we had counted on… The most tricky problem to solve first is of course the financial one (it’s always about money…). Who will pay?

The second inspiring talk was held by Alan J Cann from Annals of Botany, talking about “Social Media and Academic Publishing”. And here we are! In social media! The blog is a firts step already taken, but you can soon follow us on Facebook as well. What other social media should we be at? Where do you mingle?

Oikos’ former Managing Editor, now Director of the Editorial Office, Linus Svensson and Journal of Avian Biology’s Managing Editor Johan Nilsson. Herb beers served in medivial “glasses” at olde Hansa.

Big celebration with birthday cake for EASE turning 30! In City Town Hall.

Posted by: oikosasa | July 19, 2012

Oikos’ own jazzsinger

We are very proud to have our own jazzsinger in the Oikos Editorial Board. I’m talking about our Subject Editor Lonnie Aarssen, Queen University, Kingston Canada.

When not holding the microphone in his hand, Lonnie is doing research within the field of Plant Ecology and Evolution. His special interest is in the development and testing of new hypothesis and conceptual models. These interpret adaptive strategies for growth, survival and reproduction, and how these strategies affect abundance, distribution, composition, diversity and productivity.

Lonnie has also started to bring evolutionary thinking to the area of Human Affairs, giving courses where students “apply Darwinian evolutionary theory to the interpretation of culture and human nature, and how these effects impact on civilization and the challenges it faces for
the 21st century.” Sounds really thrilling and interesting to me!

Lonnie is also Editor at the realtively new journal “Ideas in Ecology and Evolution”.

Read more about Lonnie here:

Posted by: Jeremy Fox | July 11, 2012

I am leaving the Oikos Blog and starting my own blog

I have an announcement to make: I am leaving the Oikos Blog and starting my own blog, Dynamic Ecology. This was a difficult decision for me, and not one I took lightly. To understand my reasons for making this decision, you first need to know something about the history of the Oikos Blog and my involvement with it.

The Oikos Blog wasn’t my idea. The first I heard of the blog was when it was announced to the editorial board by Chris Lortie, the editor who was and remains in overall charge of the blog. The initial vision was basically that it would be a group blog: all the editors would post occasionally on whatever ecological topics interested them (here is a link to Chris’ video, introducing the Oikos Blog to the world). The hope, as I understood it, was that the blog would be a new way to promote the kinds of interesting conversations and new thinking that the journal had always tried to promote. Certainly, that was my own hope. I thought the blog was a great idea, a case of Oikos thinking outside the box and recognizing the potential of a new technology. There are lots of ideas in science that are worth sharing and discussing, but aren’t best shared or discussed via formal papers, or at least not only via formal papers. Besides being valuable in its own right, I had high hopes that the blog could help encourage its readers (especially students and postdocs) to take note of the journal’s content and support the journal as authors and reviewers.

At the time, I was reading a few blogs, but I’d never thought of blogging myself. But since the journal was starting a blog, I figured it might be fun to try it out. Plus, when colleagues ask me to do something, I try to default to saying “yes”.

So I started posting. I found that I enjoyed it, I seemed to be pretty good at it, and it didn’t take much of my time. But of course, everyone has to make their own time allocation decisions, and early on Chris and I were the only editors who chose to post with any frequency. I figured other folks might start posting once we built a bit of an audience, but that hasn’t happened. To be clear, I’m not criticizing my colleagues at all for this. Again, it’s up to each of us to choose how to allocate our time. I recognize that I’ve made an unconventional choice, and also that my circumstances (I’m a tenured professor in Canada) arguably make it unusually easy for me to allocate a bit of my time to blogging. But given the choices I and my colleagues have made, I don’t feel that the Oikos Blog is serving its original intended purpose as well as it could. Rather than functioning as an extension of the journal, I think the blog has become identified with me in the minds of many readers.

Which is something I find increasingly awkward. There are topics I would like to blog about, but which I avoid because they seem inappropriate even for a journal blog as broadly-defined as the Oikos Blog. There are also some new things I’d like to try that can’t really be tried on the Oikos Blog. I’ve also found that, in my own mind, I’ve started to think of the Oikos Blog as “mine”, which it isn’t. Over time, I’ve mostly stopped connecting my posts even tangentially to Oikos journal content, which is something I tried quite hard to do early on. And if someone at Oikos or Wiley were to (quite reasonably) suggest that the blog needs to develop some sort of tighter connection to the journal, I don’t know how I’d react. Which means it’s time for me to go.

I’m tremendously grateful to Chris Lortie, Dries Bonte, Tim Benton (our previous EiC), and other folks at Oikos and Wiley for coming up with the idea for the Oikos Blog, and for trusting me to run with it essentially as I saw fit (no one ever gave me any explicit or implicit instructions on posting, or exercised any pre- or post-publication review on my posts). I hope that I lived up to their trust. My decision to leave is entirely my own and in no way reflects badly on Chris, Dries, or anyone else at Oikos or Wiley. I’ve never had anything but positive feedback and support from everyone. Chris and Dries in particular (and Tim before Dries) have been enthusiastic about my blogging, and very understanding about my decision to move on, both of which I greatly appreciate. I continue to want to see the Oikos journal do well, and I’ll continue to support the journal.

I’ll also look forward to seeing what Chris et al. do with the Oikos Blog now that I’ve gone my own way. The Oikos Blog is not ending and you should definitely keep following it; I will. I’ve made some suggestions to my Oikos colleagues on cool new directions the Oikos blog could go, and I know Chris and other folks have their own ideas. Oikos Blog is going to change, but they’re going to be good changes. Right now, the blog and the journal are pretty independent. I think they can actually be greater than the sum of their parts, and I’m very much looking forward to watching that happen.

Finally, I hope you’ll check out my new blog, Dynamic Ecology. Initially, it’s going to be quite similar to my blogging for Oikos. Almost all of my old posts and the comments on them are archived over there. I already have some new content up, and I plan to try out what I think are some cool new ideas. Thank you very  much for reading my work on Oikos Blog, I’m tremendously flattered to have such a great readership. Looking forward to seeing you over on Dynamic Ecology.


Jeremy Fox

Posted by: Jeremy Fox | July 10, 2012

Evolution 2012: Tuesday notes

Evolution 2012 is over for me, couldn’t stay for the final afternoon. Highlight of the morning was watching my students talk, of course. They all did the Fox lab proud.

I enjoyed the meeting, and got out of it what I wanted to get out of it. I wasn’t blown away by the science the way I was in 2009, probably because I had a better idea what to expect, but it was still a very good meeting. It ran very well, a big thank you to the organizers, especially Howard Rundle and Andrew Symons, who I’m sure are glad to be getting their lives back in a few hours.

Time to get back to work–about which, more soon…


Posted by: Jeremy Fox | July 10, 2012

Evolution 2012: Monday highlights

Susan Bailey’s discovery of synonymous beneficial mutations continues to be the talk of the meeting, or at least that portion of the meeting that I hear about.

Another good day for conversations. Had a good chat with Carl Simpson, a paleontologist who’s using Price equation-type approaches to quantify species selection and major evolutionary transitions. It’s a rare treat to talk to someone about something highly technical, but who comes at it from a slightly different perspective than you. So you totally understand and appreciate each other (so don’t have to work hard to make yourself understood), and you aren’t arguing with each other, but yet you each have something new to say to the other. Got to catch up with some old friends, and was flattered by multiple people coming up to say how much they like the Oikos blog (or just to ask my opinion on stuff!)

Saw Peter and Rosemary Grant talk; I’d never seen them talk before, so that was cool. Peter began with a (better translation of) this bit of verse from Lucretius.

A good day for talks by my collaborators. Rees Kassen was very good on the genetics of adaptation in microbes, he included some meta-analytical-type results from his forthcoming book. And Dave Vasseur was very good on eco-evolutionary dynamics in a spatial context, looking at how dispersal affects spatial synchrony of population dynamics on the one hand, and local selection and local adaptation on the other.

Had dinner at the Manx with Nick Rowe, an economist here at Carleton in Ottawa and a blogger for Worthwhile Canadian Initiative. Really enjoyed chatting with Nick about everything from Darwin’s life and times to the contrasting cultures of ecology and economics to how blogging makes you a better teacher.

Last day tomorrow, I won’t be here the whole day. Just long enough to see my students’ talks in the morning. Don’t know if I’ll be able to do a wrap-up post, or whether I’ll just end up skipping straight to the big announcement…

Posted by: Jeremy Fox | July 9, 2012

Evolution 2012: Sunday notes

Fairly short tonight , I’m exhausted and I need to go to bed. Indeed, my exhaustion today caused me to embarrass myself when Elisabeth Pennisi, who writes for Science, asked me some questions about the meeting. I know who she is, I read her work every week, but I was so tired I just thought she was some random well-wisher. She was asking me questions about the meeting and I was just blathering semi-coherent responses. I realized what I’d done later and sent her an apologetic email with more sensible answers to her questions. But if anyone has somehow gotten the mistaken impression from this blog that I’m the slickest science communicator around, let me be the first to disabuse you of that notion.

The talk of the day for me was the very first one I saw. Susan Bailey talked about an extraordinary and totally unexpected result that cropped up in her work on experimental evolution of Pseudomonas fluorescens. She found not one but two synonymous mutations that increase fitness, by 6-8% (a quite non-trivial increase). The result is airtight: she transformed each of these mutations into the ancestral genetic background and showed that it increased fitness, despite being synonymous. Apparently “silent” mutations need not be so silent after all! She and her lab have some ideas as to how this could possibly happen, which they’re pursuing right now. Could be something like effects on rate of transcription or something. But even as it stands, just knowing what they know, it’s the most unexpected and potentially-important result I’ve seen so far.

Saw lots of stuff on evolutionary rescue today. Models and empirical work. Some of this stuff I’ve seen before, some of it was new to me. All of the experiments seem to work exactly as predicted. Always heartening to see real organisms behaving exactly the way theory says they should.

Also saw a really nice modeling talk extending Fisher’s geometrical model to the case of a directionally-moving optimum “chased” by an evolving population.  Actually had some relevance to the evolutionary rescue work. And made some predictions that would be totally straightforward (but a massive amount of work) to test with microbial evolution experiments. And I can’t remember who gave it as it wasn’t on my schedule until the last minute, and I’m too exhausted to look it up…

My own talk was today. Far from my best performance; I threw in some spontaneous jokes that ate up too much time. So I ended up running long, and the jokes didn’t even get very big laughs. The bit at the end that got cut off was just arm-waving speculation, so it’s not as if the audience missed out on too much, but still. Running long is a pretty amateur-hour thing to do for someone who’s done as many talks as I have. Hope I didn’t disappoint any readers who showed up assuming that my talks must be as awesome as my blog. I mean, I don’t think I was terrible or anything, and some folks were nice enough  to complement me afterwards, but I hold myself to high standards and I don’t really think I lived up to them today.

It was a good day for chats in the hallways with friends and colleagues, the sorts of conversations  that cause you to miss talks you were planning to see, but that’s ok because they’re good friends and good colleagues and good conversations. That sort of thing is why I love attending meetings like this.

And several people came up today and said how much they like the Oikos blog, which was really flattering. Thanks everybody! Keep watching this space, because I’m going to have a pretty big announcement to make in a couple of days…

Posted by: Jeremy Fox | July 8, 2012

Evolution 2012: Saturday notes (UPDATED)

Greetings from Evolution 2012 in delightfully summery Ottawa. My hometown of Calgary experienced an intense hailstorm centered on my house the day before I left for the meeting. I took this as an indication that it was a good time to get out of town for a few days.

The conference center is only about a year old and it’s great. Beautiful views of the canal and Parliament Hill. Just the right size for the meeting. Very easy to get back and forth between different rooms. Many of the seminar rooms are down short little hallways and so don’t open directly onto the main gathering spaces, which is good because it minimizes the noise from conversations outside the rooms.

And there are free boxed lunches! I didn’t know lunch was included. That was like the culinary equivalent of finding money in your pocket that you didn’t know you had. ;-)

p.s. In light of my deranged post about the chimes, I suppose you’re all wondering what I think of them. The answer is I don’t mind them as much as I thought I would, but I do mind them a little bit. I’d probably mind them less if they were having the intended effect more consistently. The first few talks I saw were very careful about using the chimes to time the talks as intended. But later in the day I saw many talks where one talk ended early, and so the next speaker started early, thereby defeating the purpose of the chimes. The presiders are presumably supposed to prevent this, but I think many presiders were just relying on the chimes and so not stepping in when speakers ignored the chimes. And as I expected, even when the chimes are adhered to, people are still coming in and out of the rooms while the talks are beginning and ending, simply because it takes more than 60 seconds to walk between even closely-spaced rooms. Please don’t get me wrong, I’m really enjoying the meeting, the chimes aren’t a big deal, and my opinion about the chimes is just my personal opinion. I’m sure many attendees think the chimes are great and many others don’t mind them at all.

Here are some highlights from what I saw today:

My colleague Sean Rogers did a great job summarizing his work on the genomics of ecological speciation in fishes. Very clear and very deft, compact and dense in a good way, without needing to resort to genomics jargon.

Tristan Long gave a great talk on a really clever experiment, selecting for fruit flies that can count. Yes, you can do this, apparently. You basically select for flies that, in response to an adverse stimulus, move towards a sequence of two light flashes rather than three, or three rather than four. And you have to be very careful about randomizing the properties of your flash sequences, to make sure the flies are “counting” the flashes rather than going by the total amount of time the lights are on, or the time between flashes, or the total time of the flash sequences. I envision a future in which math classes will be taught by highly evolved flies.

Anita Melnyk presented a nice series of experiments showing that Pseudomonas bacteria adapting to growth on xylose experience a more “rugged” fitness landscape than when adapting to growth on glucose. Which, as she noted briefly in the questions, is exactly the opposite of what you might have expected, given that these bacteria can metabolize glucose via two distinct biochemical pathways, but can metabolize xylose by only one. Predicting genotype-phenotype maps is hard, even for simple, well-known organisms; I’m curious if that’s something people will try to have a go at more frequently in the future.

Melanie Mueller talked about a very simple and elegant system using microbial colonizes growing on plates as a model system for studying selective sweeps in the context of populations undergoing spatial spread. Basically, it involves inoculating mixtures of different colored bacteria at a single point, and the resulting colony exhibits pretty, well-defined colored bands that change in size in predictable ways depending on the relative fitnesses of the different bacteria. Indeed, I actually wonder if the system is a little bittoo elegant, to the point of being too simple to really teach us anything new. It almost came off as engineering rather than science.

Andrew Furness talked about adaptive plasticity and bet-hedging in a really cool system, annual killifish that live in temporary ponds that dry every year. The timing of pond filling and drying is somewhat predictable (there’s a wet season, associated with reliable temperature and light cues), but somewhat unpredictable. And so as you’d expect, the fish lay diapausing eggs that initiate (and even pause!) development in response to cues, but that also develop and hatch somewhat randomly (thereby hedging their bets, rather than going “all in” in response to a possibly-unreliable cue).

Noah Ribeck explained how we’ve all been incorrectly estimating the strength of frequency-dependent selection (whoops!) The standard way to do it is to vary the initial relative frequencies of two different genotypes, then after some period of time measure their relative abundances again, and from that calculate what the selection coefficient was as a function of initial relative abundance. Which of course isn’t quite right, because you’re assuming that selection at any given initial frequency is constant over time, which it can’t possibly be in a system with frequency dependence (by definition, frequency-dependent selection coefficients change as relative abundances change). Noah derived the correct way to calculate selection coefficients for this sort of experiment, and showed that the resulting estimates differ substantially from those estimated via the usual method when frequency dependence is strong (so that relative abundances change a lot during the experiment).

Pedro Gomez did a nice poster asking how Pseudomonas fluorescens diversifies when grown under semi-natural conditions. In highly artificial lab conditions (unshaken, 6 ml batch cultures), P. fluourescens is a model system for adaptive radiation: it repeatedly diversifies into ecologically-distinct morphotypes, the two main ones being “wrinkly spreaders” and “smooths”, named for their colony morphologies when plated on agar. In nature, P. fluorescens lives in soil. And if you culture it in soil…wait for it!…it diversifies into the same frickin’ morphotypes as it does in batch cultures! Which is kind of amazing because the very specific spatial structure of batch cultures is thought to be what drives the repeatable diversification into these particular morphotypes, which occupy distinct spatial locations in batch cultures. Apparently this organism is a one trick pony! The match between the batch culture and soil diversifications is actually even tighter than that. In batch cultures you typically see a couple of different subtypes of smooths, and three or four subtypes of wrinklies–and you see all the same subtypes when you do the experment in soil! Now, it’s worth noting that in batch cultures you actually need rather specific culture conditions (e.g., specific growth medium) for the radiation to happen. And apparently those specific batch culture conditions are actually a really good analogue for this organism’s natural habitat! Who says laboratory microcosms are unrealistic?

Other notes:

“Eco-evolutionary dynamics” is hot. That kind of surprised me. I of course knew that it was hot in ecology, but I had thought that the proper evolutionary biologists would kind of dismiss it, since a fair bit of work by ecologists on “eco-evolutionary dynamics” treats the evolutionary side in kind of a weak way (a lot of it doesn’t, of course). But I’ve already seen a number of talks by people from proper evolutionary labs that sound just like the sorts of talks I’ve been seeing at the ESA meeting. Indeed, there’s a symposium on eco-evolutionary dynamics tomorrow that includes several speakers from a symposium on the same topic at the ESA meeting last year. I’m not complaining or criticizing this at all, it’s just something that surprised me a little.

Paralellism and convergence is hot. Under what circumstances is convergent evolution at the phenotypic level underpinned by the same mutations, or mutations at the same loci? But people mostly seem to be taking a case study approach to this. Maybe it’s just the brevity of the talks, but I haven’t seen any so far that have tried to place their results on this in a larger comparative or theoretical context. I don’t know, maybe we don’t yet have enough data or theory to make that worthwhile?

I saw a couple of talks on experimental bacterial evolution that pretty much came down to cross feeding (bacteria evolving to live off the metabolic waste products of other bacteria). That cross feeding evolves easily under certain culture conditions has been well-known for a long time, both experimentally and theoretically. I think it would’ve been nice to see recent work placed in the context of that literature–I wasn’t clear on if we’d learned anything really new about cross-feeding that we didn’t know before.

UPDATE: Post title corrected; it was late at night when I wrote it and for some reason I slipped into thinking I was at the ESA, where the first day of talks is always Monday.

A Canadian colleague has alerted me to a protest in Ottawa against the Canadian government’s suppression of scientific evidence, planned to coincide with the final day of Evolution 2012. Previously I’ve noted with dismay the government’s decision to cease funding the ELA; the protest organizers note that this decision can be seen as part of a larger pattern. The protest organizers (who have no connection to Evolution 2012 as far as I know) have set up a website which describes their motivation and plans. The protest will comprise a “Death of Evidence funeral procession” followed by a rally on Parliament Hill.

I emphasize that, in this as in all of my posts, I am speaking for myself, not for Oikos, its publisher, my employers, or anyone else.

Posted by: Jeremy Fox | July 3, 2012

Evolution 2012: facilitated networking

I’ve talked in the past about how to network at scientific conferences–how to overcome any shyness you might have in order to talk to the people you’d like to talk to. The Evolution 2012 meeting is trying an interesting experiment on this. Poster presenters have been given the opportunity to browse the list of attendees and select a few to invite to their poster. Their chosen invitees then get an email from the conference organizers, listing the posters to which they’ve been invited and asking them to make every effort to accept the invitation.

This seems like a very creative idea to me, not something I’d ever have thought of.* I’ll be interested to see how it works out. I would think it would facilitate some interactions that wouldn’t happen otherwise. If someone looks through a list of thousands of people and invites you to their poster, that’s a bit hard to turn down (well, maybe not if you get a whole lot of invites, but I’m guessing nobody’s going to get more than a few invitations) And while some of those interactions might end up being brief or awkward–say, a student invites Dr. Famous to their poster purely as a way to meet Dr. Famous, even though Dr. Famous works on something totally different–I don’t see that as a big deal in the grand scheme of things.

On the other hand, I would encourage those who are using this system to consider whether it might not be more effective to email people personally if you really want them to come to your poster. Everyone’s busy and has lots of demands on their time. If you want someone to allocate some of their scarce time to come to your poster, it might be more effective to allocate some of your own time to sending them a personal email. Introduce yourself and your work, and briefly state why you’d like whoever you’re inviting to come to your poster. By putting in a bit of time and effort, you’re giving an “honest signal” that’s probably more likely to elicit a positive response, at least from people about my age and older.** Just a suggestion.

They’re only doing this for posters, not talks, and I think that’s the right call given that they’re trying this out for the first time. Most people already have lots of time conflicts when it comes to choosing talks, and so using the system for talks would probably result in many declined invitations. Don’t get me wrong, I think it’s great for people to invite each other to their talks, but for now that’s probably best done the old-fashioned way, via an email directly from the speaker to the invitee.

*Maybe it seems like a no-brainer to the younger generation, with their tweeps and their Bookface and their MySpace and whatnot. (MySpace is still a thing, right?) ;-)

**”Old farts”

Posted by: Jeremy Fox | July 2, 2012

Carnival of Evolution #49

Now up at Mousetrap. Includes a contribution from yours truly. Now you know what to read on the plane to Ottawa.

Posted by: Jeremy Fox | July 2, 2012

How to become a leading ecology blogger


I swear by the techniques in panels 1 and 2. The techniques in panels 3 and 4 are totally beyond me. ;-)

Posted by: Jeremy Fox | July 1, 2012

Evolution 2012: Meeting preview

It’s almost here: the biggest (~2400 attendees) evolution conference ever! I’m excited. I’ve only ever attended the evolution meeting once before, in 2009 in Idaho when it was much smaller because there were fewer societies involved. Evolution 2009 was the best conference I’ve ever attended in terms of the quality of the presentations, the standard of science on display was just incredibly high. I’m not sure how much of that was down to me knowing less about evolution than I do about ecology and so being more easily impressed than at ecology conferences, vs. me choosing talks well, vs. all the talks just being really good. But I think it was mostly the latter. So I’m psyched for this year’s iteration.

As with any big meeting (although this meeting actually seems a bit small to a regular ESA attendee like me), you can’t see everything and shouldn’t try. You need to have a focus. My focus reflects my goal to build up my currently-modest sideline of research in evolutionary ecology, using bacteria as a model system. I’m trying to identify some interesting questions I can address with experimental microbial evolution without doing genomics (as that’s still too expensive for me, and also very far from my training). I admit that it’s not entirely clear if this is still possible. One thing I took away from the 2009 meeting was that the genomics train hadn’t only left the station, it was more like a genomics rocket that was blasting into orbit, leaving people like me far behind (unless we collaborate with the people on the rocket, of course). My hope is that, even in the genomics era, there’s still a place for clever experiments describing and evolving interesting patterns of phenotypic and fitness variation across environments. The sort of experiments that would be cool to follow up with genomics–but that are also interesting in their own right.

So my focus for the meeting is experimental microbial evolution. That won’t fill my entire schedule, and so I’ll also be seeing talks by friends, a few talks by famous people who I haven’t seen speak (just to fill out my “speaker life list”), and some talks on other topics that just sound interesting. I’m also judging the student awards, so I’ve been assigned a few student talks. In order to maximize the amount of new stuff I learn, I’ll probably skip some talks by well-known folks who I think are mostly going to say things I’ve seen them say before.

I’ll also be looking to see if studies of “field model organisms” like Darwin’s finches, Caribbean anoles, and threespine stickleback are continuing to bear fruit. As David Hembry suggests,  the fact that we know so much about these organisms makes them powerful systems for asking questions that just can’t be asked elsewhere. But the fact that these systems are so famous and popular also increases the risk of bandwagony studies, and studies that just fill in minor details in a nearly-complete picture. Doing really original and important work in these systems is in some ways especially difficult, not especially easy.

So what am I going to see? I don’t have time to preview my entire schedule in detail, plus it wouldn’t necessarily be of huge interest unless your focus was similar to mine. But as a summary, I’ve scheduled pretty much everything on experimental evolution of bacteria, phage, and yeast. That includes a bunch of talks and posters from the groups of folks like Rich Lenski, Rees Kassen, Graham Bell, Mike Travisano, and others. Here are some talks on other topics that I’m planning to see, all of which should be very good, so I encourage you to check them out as well:

  • Sat. 9:15, Canada Hall 2-3: Sean Rogers on Genomic approaches to studying speciation in postglacial fishes. You know how I said that genomics is taking off like a rocket? My Calgary colleague Sean Rogers is like the pilot of that rocket.
  • Sat. 3:15, Canada Hall 2-3: Carl Boettiger on Detecting evolutionary regime shifts with comparative phylogenetics. Carl is super-smart, his talk at ESA last year on detecting early warnings of ecological regime shifts blew me away. Now he’s turning his attention to analogous problems in evolution. Looks like he has some really creative ideas in terms of both identifying the problem and on how to solve it.
  • Sat. 3:45, Room 208: Andrew Furness on Adaptation to environmental unpredictability: phenotypic plasticity and bet-hedging in egg diapause. I think bet-hedging is cool (keep trying and failing to think of something I could do on it myself), so I want to see this.
  • Sat. 4:00, Room 215: Leithen M’Gonigle on Sexual selection enables long-term coexistence despite ecological equivalence. I’m interested in coexistence, and results coming out of my own lab (see below) suggest that sexual reproduction combined with species interactions creates some novel effects on coexistence. This talk sounds like it might be broadly related. Plus, while I don’t know Dr. M’Gonigle, some of the co-authors (Sally Otto, Ulf Dieckmann) are among the best theoreticians going.
  • Sun. 11:00, Canada Hall 2-3: Bronwyn Rayfield on Habitat connectivity and population dynamics in experimental networks. Bronwyn is sharp, she works with my friend and collaborator Andy Gonzalez, and like my students (see below) she works on spatial population dynamics using powerful lab-based model systems. So I really want to see this.
  • Sun. 1:30, Room 201: Jeremy Fox on Local adaptation and maladaptation in space and time: aquatic bacteria as a model system. Yours truly will talk about what I think is a novel experimental approach, doing reciprocal transplants across time as well as space in order to test for local adaptation. Yes, you can do this; all you need is a “time machine” (to see what I mean you’ll have to come to the talk).  And I’ll be presenting what I think are some surprising results. And if that’s not enough incentive, there will be free beer.
  • Sun. 4:00, Room 204: Ben Haller on Solving the paradox of stasis: Stabilizing selection and the limits of detection. Ben is a graduate student with Andrew Hendry. He won the “craziest thing you’ve ever done for science” thread by doing a simulation modeling study, the results of which required 2.5 billion regressions to analyze. I like to imagine Ben as Dr. Evil, putting his pinkie to his mouth and announcing that he plans to run one milllllllion regressions. Only to have a member of his committee clear his throat and whisper that one million regressions isn’t really all that impressive these days. To which Ben responds by going “Ok, two-point-five…[sidelong glance at committee member] billlllllion regressions!” (click the link if you have no idea what I’m talking about). In seriousness, this does sound like an interesting talk, independent of the whole “an-approach-so-crazy-only-a-grad-student-would-do-it” angle. ;-)
  • Mon. 4:30, Room 210: Dave Vasseur on Local adaptation alters the impact of spatial population synchrony. David is a good friend and collaborator, but I’d go to this even if he wasn’t either. Because David is really sharp and gives a very good talk. This is a theoretical talk on eco-evolutionary dynamics, looking at the interplay of population cycles, dispersal, and local selection. Dispersal easily synchronizes population cycles over space, which you’d think would result in temporally-fluctuating but spatially-uniform selection pressures and hence lack of local adaptation. But it’s not as simple as that, because (if I correctly recall Dave’s summary of the talk) localized selection can alter the spatial synchrony of the system. I suspect every microcosmologist who sees this is going to rush out to try to be the first to test it.
  • Tue. 8:45 am, Room 203: Stephen Hausch on Diversity, coexistence, and competitive ability: The effect of intraspecific diversity on invasibility and invadability in bruchid beetles. Full disclosure: Stephen is my student (co-advised with Steve Vamosi). Full honesty: this talk is really cool. In particular, if you’re into eco-evolutionary dynamics, you need to see this. Stephen has done a massive experiment looking at how intraspecific genetic diversity affects coexistence (mutual invasibility) in two competing species of bean beetles. The effects of intraspecific genetic diversity on species coexistence is an important, under-studied, and hot topic right now; the best current thinking on how it works was the subject of a major review in TREE recently. As far as we can tell, Stephen’s results can’t be explained by any of the ideas in that review.
  • Tue. 9:00, Room 203: Colin Olito on The interacting roles of foraging biology, flowering phenology and trait evolution in determining pollination network structure. After you see Stephen’s talk, just stay where you are so you can see my second student, Colin Olito. It’ll be quite different than Stephen’s talk, but equally good. It’s a modeling talk, looking at how the structure of plant-pollinator interaction networks emerges from the underlying phenologies of flowering plants and pollinators and the foraging decisions of pollinators. A novel aspect of this model is incorporating eco-evolutionary dynamics. Pollinator foraging and species’ current phenologies creates selection pressures that shift plant phenologies (e.g., to avoid competition for pollinators), which feeds back to alter the pollinator foraging and thus the selection pressures. The model builds on previous work by Devaux and Lande, who radically simplified pollinator foraging and phenology. It is quite rich and complicated (as is necessary if you want to ground your model in reality rather than in mathematical convenience), but not intractably so. For instance, you can turn off different features of the model so as to ask how they affect the model behavior, particularly the long-run plant-pollinator interaction networks structure. If you, like Colin and I, are dissatisfied with theoretical studies of interaction networks that are disconnected from real plant-pollinator interaction biology, this is the talk for you.
  • Tue. 11:00, Room 203: Geoff Legault on The threshold for dispersal-induced spatial synchrony in a model system. I can only assume that, in scheduling all three of my students for the final day, the organizers were trying to save the best for last. ;-) Geoff’s talk is on the latest results from my lab on spatial synchrony of population cycles. In previous work, we’ve shown in microcosm experiments that  dispersal between habitat patches “phase locks” the predator-prey cycles in those patches, so that prey populations in different patches all cycle  in near-perfect synchrony (i.e. in phase). This strongly suggests that phase locking may explain why cyclic populations in nature often are synchronized over vast areas. But it also raises a question: how does synchrony vary as a function of dispersal rate? In theory, the effect of dispersal rate on synchrony should be highly nonlinear, basically a threshold effect: you either have enough dispersal to produce phase locking, and thus very high synchrony, or else you don’t have enough, in which case you get no synchrony at all. We did an experiment to test that prediction, the first ever done in ecology as far as we know (analogous experiments have been done in fields like neuroscience, which deals with synchrony of neuronal firing).
Posted by: Jeremy Fox | July 1, 2012

Evolution 2012: use the scheduling app

Presenters at Evolution 2012 know about this, but I’m not sure if all attendees do: there’s a slick app for making your personal schedule. You can access if from any browser-equipped device. Its fully searchable as well as browsable, it auto-updates if there are cancellations (nice!), it includes profiles of all presenters and attendees (you can update your own profile to add all sorts of information). It also lets you take and email notes, but  I’m guessing most attendees already have their own preferred apps for doing that.

The ESA has had a browser-based scheduling app for years, and while I think it’s still pretty good, it’s not optimized for mobile devices and lacks some of the features of the Evolution 2012 app. Might be time for the ESA to look into upgrading.

Posted by: Jeremy Fox | June 29, 2012

The ecology of hipsters

The Dependent magazine wins the internet by estimating the population density of hipsters in Vancouver, using capture-recapture methods.

If they continue sampling and build up a time series, Ted Hart at UBC can show them how to estimate past hipster abundances.

HT Jeremy Yoder.

Posted by: Jeremy Fox | June 29, 2012

Advice: how to prep for, and attend, a conference

A mix of serious and silly advice on conferences, here.

HT American Naturalist, via Twitter.

FINAL UPDATE: The snark in this post is out of line, and for that I apologize to Howard Rundle and the other Evolution 2012 organizers. It was and remains true that I’m personally skeptical of the need for the chimes, based on my own experience over many years at an even larger meeting (the ESA). But as previous updates and Howard’s comment indicate, the organizers have good reasons for wanting to try the chimes. It was wrong of me to write a snarky post based on my own gut reaction to the idea without first checking in with the organizers.

As noted by Howard, myself, and others in the comments, it’s impossible to structure a large meeting in a way that will please everyone, so the only thing you can do is try to please as many people as possible. Which is exactly what the organizers are trying to do with the chimes. The chimes are an experiment, and the organizers deserve credit for carefully considering their options and deciding to give this experiment a go.

Evolution 2012 is going to be a great meeting, chimes or not, and it’s a massive amount of work to organize. Like all the attendees, I’m very grateful to Howard and his fellow organizers for putting this meeting together. And I appreciate him taking a bit of his very scarce time to stop by and clarify the reasoning behind the chimes.

In many elementary schools, a bell sounds throughout the building to indicate the end of one class, and a few minutes later another bell sounds to indicate the start of the next class. This practice is so common it’s given rise to popular slang, such as “saved by the bell“.

I have just received an email indicating that the Evolution 2012 meeting is going to work the same way (emphasis added):

You are scheduled to give a talk at the upcoming 1st Joint Congress on Evolutionary Biology in Ottawa. The purpose of this message is to provide some additional information about timing. All talks in the general concurrent sessions are 14 min MAXIMUM, INCLUDING QUESTIONS. A building-wide chime system will be in place to help keep all concurrent sessions on time and in synch, and to allow 1 min  movement time for attendees to switch rooms between talks (as well as time for the next speaker to get set up ). Using the building PA system, a brief start chime will be broadcast every 15 min on the hour (i.e. at xx:00, xx:15,  xx:30, xx:45), and then a 2nd slightly different ending chime at 14 min., 29 min, 44 min. and 59 min. past the hour. For example, if your talk is at 9:00 am, then it will begin with a start chime at 9:00 am and finish with an end chime at 9:14 am. 1 min later a start chime will indicate the beginning of the next talk (9:15 am). There will be a digital  clock in each room, situated so as to be visible to both the speaker and  the volunteer chair of each session, and it will be synchronized with the chimes.

It is unclear if attendees will also require hall passes to go to the bathroom.

I’m not looking forward to having my thoughts and conversations interrupted by chimes broadcast throughout the building every 15 minutes. Even if the chimes can only be heard in the seminar rooms (which I doubt), they’ll still be incredibly annoying. And no, I don’t think it will be worth it to avoid parallel sessions drifting 30-60 seconds out of sync with one another.

UPDATE: Just to be clear, the email also says that there will be a digital clock in each room, synchronized to the chimes and visible to both the presenter and presider. So the chimes are in addition to and not a substitute for clocks!

UPDATE#2: By the way, not all talks are 15 minutes–symposium talks and presidential and award addresses are longer. So those talks are going to have chimes sounding while the talks are going on! Correction: I am informed by the meeting organizers that the chimes will not sound in rooms hosting longer talks, with the exception of a small number of longer talks being held in one particular room that is also hosting shorter talks.

Hopefully, if enough people complain early enough, they’ll shut the chimes off. Peeps: start complaining on Twitter right now (#evol2012)!

UPDATE#3: And if you say “Well, we’ll get used to it”, my responses are (i) speak for yourself! and (ii) why the frick should we have to get used to it? If someone says to you, “I’m going to cause you discomfort twice every 15 minutes for no reason,” your response should not be “Ok, go ahead, I’ll get used to it.” (Plus, are you seriously claiming you’re going to get used to chimes going off during the longer talks?)

UPDATE#4: I have corresponded with some of the meeting organizers, who were gracious enough to reply very quickly to the concerns raised in this post. They said that the chimes are a response to complaints about parallel sessions getting out of sync in past years, they will be very short (2-3 seconds) and will serve only to indicate the time (as opposed to drowning out speakers), and now that the decision’s been made to use them it would cost $4000 to turn them off. (They also suggest that the chimes will be expected and therefore less bothersome than cell phones going off, but the relevance of this fact is unclear to me. You can’t justify deciding to disturb people by pointing out that other things disturb people even more).

So the organizers clearly had their reasons, and I certainly understand that it’s now too costly for them to change their minds. And I’m very glad to hear that longer talks (mostly) won’t be interrupted. I remain unconvinced that the cure is better than the disease here, but we’ll see–perhaps I and commenter Jeremy Yoder are in a minority on this. The reaction of attendees should reveal whether most folks prefer chimes to sessions drifting slightly out of sync.

Posted by: Jeremy Fox | June 28, 2012

Why “Lonesome George” was lonesome

It’s not why you think. ;-)

(warning: text a little NSFW)

Press release: The academic jungle: ecosystem modelling reveals why women are driven out of research. DOI: 10.1111/j.1600-0706.2012.20601.x
A large proportion of women and a growing number of men wish to work part-time in order to balance the demands of family and work.  However part-time employment in academia remains rare, and role models successfully balancing both teaching and research activities, are exceedingly rare.    There is a need to make part-time work more accessible and more viable in academia, in order to attract and retain more women in science and engineering research.   This paper identifies some of the most common and difficult issues faced by those working part-time in academia, and provides guidance about how to navigate around these.   It also identifies barriers faced by part-time academic staff which need to be addressed at a university level.

Assessing research performance of part-time staff is particularly difficult. Increasingly, research performance is assessed using metrics (such as number of papers, number of citations, h-index etc).   Application of these metrics can promote research output within an organization, however they can also undermine diversity.   In particular, research metrics are strongly biased towards full-time continuous employment, and penalize academics who take time off before becoming well established in their fields; e.g. women who part-time while raising their families.  This paper outlines the mechanisms by which metrics undermine the ability of women to participate in research if they work part-time.  This is done through an ecological analogy; just as a species is only sustainable if its population exceeds a minimum critical threshold, so too do researchers need to exceed a critical mass in order to attract more funding, students and high quality collaborators and so maintain their productivity.  In addition, the research production rate, analogous to the population birth rate, needs to exceed a critical rate if the population is to grow and survive –  these higher production rates are harder to achieve when part-time . A lower production rate is usually assumed to have a proportional effect on research outputs, but the ecological model suggests far more complex consequences on overall research productivity. If women have children before they are well established in their field, our model suggests that they will struggle to remain competitive.   This explains the observed drift of women from research to teaching, where performance is assessed on current rather than accumulated historical performance.

There are further analogies between ecosystems and universities: in both cases, diversity underpins resilience.  Optimizing a system, whether it be a forest or a faculty, to a narrow set of criteria is likely to undermine the ability of that system to respond to disturbance.   In the case of universities, over-reliance on research metrics could undermine the long-term quest for excellence by reducing the pool of talent from which our researchers are drawn.

The authors provide clear advice on how to address these issues:

  • part-timers should be strategic and concentrate on either research or teaching; they need wise mentoring, and need to brave to be the “odd ones out” in a system overwhelming dominated by full-time continuous employment.
  • university managers should use metrics cautiously, and implement schemes to ensure that part-time work and career breaks are not “one-way tickets” out of research.
Posted by: Jeremy Fox | June 25, 2012

Upcoming group blog on Open Data

This is pretty tangential, even for me, but I thought it might be of interest to some readers. Ecology, like many fields (including social science as well as hard science), is seeing a push towards data sharing becoming the norm rather than the exception (e.g., many leading ecology journals support the data sharing repository DataDryad). But in some areas, like politics, hard questions can be asked about whether Open Data is a good thing, or if it is a good thing, who or what it’s good for. Crooked Timber is going to be hosting a group discussion of Open Data, with a bunch of prominent and very sharp contributors, mostly from the social sciences. The focus looks like it will mostly be on Open Data in a government/politics context, but there might be something for those of you with more scientific interests. And of course, these two shade into each other, as I’m sure frequent commenter Jim Bouldin could discuss in the context of climate change politics and associated fights over access to raw climatological data.

If you can’t get enough of heavyweight intellectuals arguing about how to think about group selection, Steven Pinker has a lengthy post at The Edge, which has drawn responses from Dan Dennett and David Queller, among others (Queller’s response is particularly on point, I think).

HT Joan Strassman



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