Navas M.-L.,CNRS Center of Evolutionary and Functional Ecology
Weed Research | Year: 2012
The trait-based approach to plant functional ecology has gained considerable attention over the last two decades, allowing ecologists to address questions relating to species distribution, community assembly and ecosystem functioning. We show here how this approach can be used to address these issues for weed ecology in a new way, allowing research to shift from purely weed control issues to a more global understanding of the impact of weed communities on the agro-ecosystem. We review how weed species are sorted by environmental factors and management according to the value of traits and the role thereof in the assembly of weed communities. How weed trait values and their distribution within communities affect agro-ecosystem processes is discussed in relation to loss of crop production. We also introduce the question of the impact of weed functional structure on ecosystem services and suggest some directions for research at species, community and agro-ecosystem levels. © 2012 The Author. Weed Research © 2012 European Weed Research Society.
Benhamou S.,CNRS Center of Evolutionary and Functional Ecology
Ecology Letters | Year: 2014
With recent technological advances in tracking devices, movements of numerous animal species can be recorded with a high resolution over large spatial and temporal ranges. This opens promising perspectives for understanding how an animal perceives and reacts to the multi-scale structure of its environment. Yet, conceptual issues such as confusion between movement scales and searching modes prevent us from properly inferring the movement processes at different scales. Here, I propose to build on stationarity (i.e. stability of statistical parameters) to develop a consistent theoretical framework in which animal movements are modelled as a generic composite multi-scale multi-mode random walk model. This framework makes it possible to highlight scales that are relevant to the studied animal, the nature of the behavioural processes that operate at each of these different scales, and the way in which the processes involved at any given scale can interact with those operating at smaller or larger scales. This explicitly scale-focused approach should help properly analyse actual movements by relating, for each scale and each mode, the values of the main model parameters (speed, short- and long-term persistences, degree of stochasticity) to the animal's needs and skills and its response to its environment at multiple scales. © 2013 John Wiley & Sons Ltd/CNRS.
Debarre F.,CNRS Center of Evolutionary and Functional Ecology
The American naturalist | Year: 2012
Most models for the evolution of host defense against parasites assume that host populations are not spatially structured. Yet local interactions and limited dispersal can strongly affect the evolutionary outcome, because they significantly alter epidemiological feedbacks and the spatial genetic structuring of the host and pathogen populations. We provide a general framework to study the evolution of a number of host life-history traits in a spatially structured host population infected by a horizontally transmitted parasite. Our analysis teases apart the selective pressures on hosts and helps disentangle the direct fitness effect of mutations and their indirect effects via the influence of spatial structure on the genetic, demographic, and epidemiological structure of the host population. We then illustrate the evolutionary consequences of spatial structure by focusing on the evolution of two host defense strategies against parasitism: suicide upon infection and reduced transmission. Because they bring no direct fitness benefit, these strategies are counterselected or selectively neutral in a nonspatial setting, but we show that they can be selected for in a spatially structured environment. Our study thus sheds light on the evolution of altruistic defense mechanisms that have been observed in various biological systems. © 2011 by The University of Chicago.
Cheptou P.-O.,CNRS Center of Evolutionary and Functional Ecology
Annals of Botany | Year: 2012
BackgroundBakers Law states that colonization by self-compatible organisms is more likely to be successful than colonization by self-incompatible organisms because of the ability for self-compatible organisms to produce offspring without pollination agents. This simple model has proved very successful in plant ecology and has been applied to various contexts, including colonizing or ruderal species, islands colonizers, invasive species or mating system variation across distribution ranges. Moreover, it is one of the only models in population biology linking two traits of major importance in ecology, namely dispersal and mating system. Although Bakers Law has stimulated a large number of empirical studies reporting the association of self-fertilization and colonizing ability in various contexts, the data have not established a general pattern for the association of traits. ScopeIn this paper, a critical position is adopted to discuss and clarify Bakers Law. From the literature referring to Bakers Law, an analysis made regarding how mating success is considered in such studies and discrepancies with population genetics theory of mating systems are highlighted. The data reporting the association of self-fertilization and colonizing ability are also briefly reviewed and the potential bias in interpretation is discussed. Lastly, a recent theoretical model analysing the link between colonizing ability and self-fertilization is considered. Conclusions Evolutionary predictions are actually more complex than Bakers intuitive arguments. It appears that Bakers Law encompasses a variety of ecological scenarios, which cannot be considered a priori as equivalent. Questioning what has been considered as self-evident for more than 50 years seems a reasonable objective to analyse in-depth dispersal and mating system traits. © The Author 2011.
Lukas D.,University of Cambridge |
Huchard E.,University of Cambridge |
Huchard E.,CNRS Center of Evolutionary and Functional Ecology
Science | Year: 2014
Male mammals often kill conspecific offspring. The benefits of such infanticide to males, and its costs to females, probably vary across mammalian social and mating systems.We used comparative analyses to show that infanticide primarily evolves in social mammals in which reproduction is monopolized by a minority of males. It has not promoted social counterstrategies such as female gregariousness, pair living, or changes in group size and sex ratio, but is successfully prevented by female sexual promiscuity, a paternity dilution strategy. These findings indicate that infanticide is a consequence, rather than a cause, of contrasts in mammalian social systems affecting the intensity of sexual conflict.
Chevin L.M.,CNRS Center of Evolutionary and Functional Ecology
Philosophical transactions of the Royal Society of London. Series B, Biological sciences | Year: 2013
Population persistence in a new and stressful environment can be influenced by the plastic phenotypic responses of individuals to this environment, and by the genetic evolution of plasticity itself. This process has recently been investigated theoretically, but testing the quantitative predictions in the wild is challenging because (i) there are usually not enough population replicates to deal with the stochasticity of the evolutionary process, (ii) environmental conditions are not controlled, and (iii) measuring selection and the inheritance of traits affecting fitness is difficult in natural populations. As an alternative, predictions from theory can be tested in the laboratory with controlled experiments. To illustrate the feasibility of this approach, we briefly review the literature on the experimental evolution of plasticity, and on evolutionary rescue in the laboratory, paying particular attention to differences and similarities between microbes and multicellular eukaryotes. We then highlight a set of questions that could be addressed using this framework, which would enable testing the robustness of theoretical predictions, and provide new insights into areas that have received little theoretical attention to date.
Debarre F.,CNRS Center of Evolutionary and Functional Ecology |
Lenormand T.,CNRS Center of Evolutionary and Functional Ecology
Ecology Letters | Year: 2011
Understanding the conditions for the stable coexistence of different alleles or species is a central topic in theoretical evolution and ecology. Different causes for stable polymorphism or species coexistence have already been identified but they can be grouped into a limited number of general processes. This article is devoted to the presentation and illustration of a new process, which we call 'habitat boundary polymorphism', and which relies on two key ingredients: habitat heterogeneity and distance-limited dispersal. Under direct competition and with fixed population densities, we show that this process allows for the equilibrium coexistence of more than n types in a n-habitat environment. Distance-limited dispersal indeed creates local maladaptation at habitat edges, which leaves room for the invasion of more generalist alleles or species. This mechanism provides a generic yet neglected process for the maintenance of polymorphism or species coexistence. © 2011 Blackwell Publishing Ltd/CNRS.
Charmantier A.,CNRS Center of Evolutionary and Functional Ecology |
Gienapp P.,Netherlands Institute of Ecology
Evolutionary Applications | Year: 2014
There are multiple observations around the globe showing that in many avian species, both the timing of migration and breeding have advanced, due to warmer springs. Here, we review the literature to disentangle the actions of evolutionary changes in response to selection induced by climate change versus changes due to individual plasticity, that is, the capacity of an individual to adjust its phenology to environmental variables. Within the abundant literature on climate change effects on bird phenology, only a small fraction of studies are based on individual data, yet individual data are required to quantify the relative importance of plastic versus evolutionary responses. While plasticity seems common and often adaptive, no study so far has provided direct evidence for an evolutionary response of bird phenology to current climate change. This assessment leads us to notice the alarming lack of tests for microevolutionary changes in bird phenology in response to climate change, in contrast with the abundant claims on this issue. In short, at present we cannot draw reliable conclusions on the processes underlying the observed patterns of advanced phenology in birds. Rapid improvements in techniques for gathering and analysing individual data offer exciting possibilities that should encourage research activity to fill this knowledge gap. © 2013 The Authors. Evolutionary Applications published by John Wiley & Sons Ltd.
Penuelas J.,Autonomous University of Barcelona |
Staudt M.,CNRS Center of Evolutionary and Functional Ecology
Trends in Plant Science | Year: 2010
Biogenic volatile organic compounds (BVOCs) produced by plants are involved in plant growth, reproduction and defense. They are emitted from vegetation into the atmosphere and have significant effects on other organisms and on atmospheric chemistry and physics. Here, we review current knowledge on the alteration of BVOC emission rates due to climate and global changes: warming, drought, land use changes, high atmospheric CO2 concentrations, ozone and enhanced UV radiation. These alterations are very variable depending on the doses, timing, BVOC and species, but in overall terms are likely to increase BVOC emissions. These changed emissions can lead to unforeseeable consequences for the biosphere structure and functioning, and can disturb biosphere feedback on atmospheric chemistry and climate with a direction and intensity that warrants in-depth investigation. © 2009 Elsevier Ltd. All rights reserved.
Lion S.,CNRS Center of Evolutionary and Functional Ecology
Journal of Evolutionary Biology | Year: 2013
The coinfection of a host by several parasite strains is known to affect selective pressures on parasite strategies of host exploitation. I present a general model of coinfections that ties together kin selection models of virulence evolution and epidemiological models of multiple infections. I derive an analytical expression for the invasion fitness of a rare mutant in a population with an arbitrary distribution of the multiplicity of infection (MOI) across hosts. When a single mutation affects parasite strategies in all MOI classes, I show that the evolutionarily stable level of virulence depends on a demographic average of within-host relatedness across all host classes. This generalization of previous kin selection results requires that within-host parasite densities do not vary between hosts. When host exploitation strategies are allowed to vary across classes, I show that the strategy of host exploitation in a focal MOI class depends on the relative magnitudes of parasite reproductive values in the focal class and in the next. Thus, in contrast to previous findings, lower within-host relatedness in competitive parasite interactions can potentially correspond to either higher or lower levels of virulence. © 2013 European Society For Evolutionary Biology.