Figure 1 - available via license: Creative Commons Attribution 4.0 International
Content may be subject to copyright.
Time-series of stochastic simulations depicting evolution of species. In all simulations species were introduced at the high colonization (low competitive) end of trait space and allowed to subsequently evolve For all simulations shown d = 0.6, = 0.654, and the average mutation in trait value β, for every bout of reproduction, is μ = 0.001* (1/N) unless otherwise stated (see Methods for details). (A) Simulation when community is defined by classic competition-colonization trade-off of Equation (1) with the minimum threshold, β0, indicated by the vertical dashed line. (B) Evolutionary dynamics in a one-species system for the generalized metapopulation model of Equation (2) with k = 60. Species now avoid evolution to stochastic extinction by evolving to a singular strategy, β1*, some distance above the minimum threshold β0. (C) Illustration of disruptive selection with high average mutation distance (μ = 0.0095*(1/N)) in trait value and intermediate k values (k = 60). (D) Community assembly for a large number of species for k = 60 and with distinct phenotypic distances between strategies corresponding to predictions from Equation (9).
Source publication
We utilize a standard competition-colonization metapopulation model in order to study the evolutionary assembly of species. Based on earlier work showing how models assuming strict competitive hierarchies will likely lead to runaway evolution and self-extinction for all species, we adopt a continuous competition function that allows for levels of u...
Citations
... varying dispersal ability across species, or develop an alternative configuration where traits evolve as a tradeoff between local competitive ability and colonization ability [28,29]. Ecoevolutionary simulation models with explicit consideration of sequence evolution (e.g., NEMO-AGE [17], sPEGG [24], SLiM 4 [20]) (see Figure I in Box 1) allow tests for the role that genetic architecture plays in structuring eco-evolutionary dynamics (e.g., species with similar niche axes but different degrees of standing genetic variation, mating systems, or other properties that impact adaptive capacity [30]). ...
While the reciprocal effects of ecological and evolutionary dynamics are increasingly recognized as an important driver for biodiversity, detection of such eco-evolutionary feedbacks, their underlying mechanisms, and their consequences remains challenging. Eco-evolutionary dynamics occur at different spatial and temporal scales and can leave signatures at different levels of organization (e.g., gene, protein, trait, community) that are often difficult to detect. Recent advances in statistical methods combined with alternative hypothesis testing provides a promising approach to identify potential eco-evolutionary drivers for observed data even in non-model systems that are not amenable to experimental manipulation. We discuss recent advances in eco-evolutionary modeling and statistical methods and discuss challenges for fitting mechanistic models to eco-evolutionary data.
... Despite the importance of life history and performance trade-offs in shaping ecological communities (Chesson, 2000;Kneitel & Chase, 2004;Tilman, 1990), and the strides in theoretical work on the competition-colonization trade-off (e.g. Burton et al., 2010;Calcagno et al., 2006;Figueiredo & Connolly, 2012;Pillai & Guichard, 2012), there remains considerable uncertainty about the generality of this trade-off in real systems and therefore whether it plays a significant role in facilitating co-existence across diverse ecological communities (Pastore et al., 2014;Yu et al., 2004;Yu & Wilson, 2001). ...
Performance trade‐offs between competition and colonization can be an important mechanism facilitating regional coexistence of competitors. However, empirical evidence for this trade‐off is mixed, raising questions about the extent to which it shapes diverse ecological communities. Here, we outline a framework that can be used to improve empirical tests of the competition‐colonization trade‐off.
We argue that tests of the competition‐colonization trade‐off have been diverted into unproductive paths when dispersal mode and/or competition type have been inadequately defined. To generate comparative predictions of associations between dispersal and competitive performance, we develop a conceptual trait‐based framework that clarifies how dispersal mode and type of competitor shape this trade‐off at the stage of dispersal and establishment in a variety of systems. Our framework suggests that competition‐colonization trade‐offs may be less common for passively dispersing organisms when competitive dominants are those best able to withstand resource depletion (competitive response), and for active dispersers when traits for dispersal performance are positively associated with resource pre‐emption (competitive effect).
The framework presented here is designed to provide common ground for researchers working in different systems in order to prompt more effective assessment of this performance trade‐off and its role in shaping community structure. By delineating key system properties that mediate the trade‐off between competitive and colonization performance and their relationship to individual‐level traits, researchers in disparate systems can structure their predictions about this trade‐off more effectively and compare across systems more clearly.
... We can consider two extreme cases of community assembly: (i) where immigration events are common enough to completely outpace the effects of in situ coevolution, we recover the classic "invasion-structured" food webs; and, (ii) where evolution has plenty of time to proceed in-between invasion events, we may obtain "adaptive radiations", i.e. the in situ formation of new species by evolution (see also Vanoverbeke et al., 2016). This second extreme case is sometimes called "evolutionary community assembly" (Bonsall et al., 2004;Br€ annstr€ om et al., 2012;Doebeli and Dieckmann, 2000;HilleRisLambers et al., 2012;Loeuille and Leibold, 2014;Pillai and Guichard, 2012;Tokita and Yasutomi, 2003). Evolutionary community assembly has been mostly applied to competitive communities, but some studies have considered evolutionary diversification in the context of food webs. ...
To understand why and how species invade ecosystems, ecologists have made heavy use of observations of species colonization on islands. The theory of island biogeography, developed in the 1960s by R.H. MacArthur and E.O. Wilson, has had a tremendous impact on how ecologists understand the link between species diversity and characteristics of the habitat such as isolation and size. Recent developments have described how the inclusion of information on trophic interactions can further inform our understanding of island biogeography dynamics. Here, we extend the trophic theory of island biogeography to assess whether certain food web properties on the mainland affect colonization/extinction dynamics of species on islands. Our results highlight that both food web connectance and size on the mainland increase species diversity on islands. We also highlight that more heavily tailed degree distributions in the mainland food web correlate with less frequent but potentially more important extinction cascades on islands. The average shortest path to a basal species on islands follows a hump-shaped curve as a function of realized species richness, with food chains slightly longer than on the mainland at intermediate species richness. More modular mainland webs are also less persistent on islands. We discuss our results in the context of global changes and from the viewpoint of community assembly rules, aiming at pinpointing further theoretical developments needed to make the trophic theory of island biogeography even more useful for fundamental and applied ecology.
... We can consider two extreme cases of community assembly: (i) where immigration events are common enough to completely outpace the effects of in situ coevolution, we recover the classic "invasion-structured" food webs; and, (ii) where evolution has plenty of time to proceed in-between invasion events, we may obtain "adaptive radiations", i.e. the in situ formation of new species by evolution (see also Vanoverbeke et al., 2016). This second extreme case is sometimes called "evolutionary community assembly" (Bonsall et al., 2004;Br€ annstr€ om et al., 2012;Doebeli and Dieckmann, 2000;HilleRisLambers et al., 2012;Loeuille and Leibold, 2014;Pillai and Guichard, 2012;Tokita and Yasutomi, 2003). Evolutionary community assembly has been mostly applied to competitive communities, but some studies have considered evolutionary diversification in the context of food webs. ...
... Following the theory of competition exclusion that suggest that two species with same niche requirement cannot co-exist [40][41] [42], suggests that wild herbivores and livestock will not be possible to co-exist in the Delta. Nevertheless, meta-populations theories suggest that spatio-temporal distribution and allocation of resources through colonisation of unused resources, coexistence of species with similar ecological niche is possible [43] [44]. Therefore, if strategies that promotes the principles of metapopulations dynamics are practiced, wild herbivores and livestock can co-exist. ...
... Following the theory of competition exclusion that suggest that two species with same niche requirement cannot co-exist [40][41] [42], suggests that wild herbivores and livestock will not be possible to co-exist in the Delta. Nevertheless, meta-populations theories suggest that spatio-temporal distribution and allocation of resources through colonisation of unused resources, coexistence of species with similar ecological niche is possible [43] [44]. Therefore, if strategies that promotes the principles of metapopulations dynamics are practiced, wild herbivores and livestock can co-exist. ...
In southern Africa, coexistence between human and wildlife is hampered by the rate of conflict between the two, especially where the two share a common resource. We investigated this in the Okavango Delta using crop raiding and livestock predation by wildlife. We found that both crop raiding and livestock predation were significant increase from 1992 to 2012 around the Okavango Delta. Potential strategies (conservation agriculture, game ranching and community natural resource management) to reduce the conflict and promote coexistence are suggested.
... We studied the evolution of continuous asymmetric traits that entail a tradeoff between better ability to compete locally with neighboring population and better ability to disperse offspring. Specifically, in one variant we considered a tradeoff between local competition and global dispersal (colonization-competition tradeoff, [17,[21][22][23]42]); in another variant we considered a cooperative trait that increases the ability of neighbors to disperse offspring but incurs an individual cost [26,29,[43][44][45]. In both variants, we considered two basic parameters: strength of local selection, s, and potential mean number of dispersers that initiate a population in a newly formed patch (seeders), α. ...
... Similarly, in the context of ecological communities, it was suggested that species with higher fecundity may stably sustain by colonizing patches that are unoccupied by species with stronger competitive abilities (colonization-competition tradeoff), which may promote coexistence between several species with different trait values [22,23]. Moreover, it was shown that moderated strengths of local disruptive selection may promote multimodal body-size distributions [21], and may also promote coexistence between a few branches of coexisting species at the community level [17,18,25,42]. In the present study, we demonstrated that the increment in polymorphism with increased selection is a consequence of the evolutionary dynamics and is insensitive to the form of the fitness function. ...
A major conundrum in evolution is that, despite natural selection, polymorphism is still omnipresent in nature: Numerous species exhibit multiple morphs, namely several abundant values of an important trait. Polymorphism is particularly prevalent in asymmetric traits, which are beneficial to their carrier in disruptive competitive interference but at the same time bear disadvantages in other aspects, such as greater mortality or lower fecundity. Here we focus on asymmetric traits in which a better competitor disperses fewer offspring in the absence of competition. We report a general pattern in which polymorphic populations emerge when disruptive selection increases: The stronger the selection, the greater the number of morphs that evolve. This pattern is general and is insensitive to the form of the fitness function. The pattern is somewhat counterintuitive since directional selection is excepted to sharpen the trait distribution and thereby reduce its diversity (but note that similar patterns were suggested in studies that demonstrated increased biodiversity as local selection increases in ecological communities). We explain the underlying mechanism in which stronger selection drives the population towards more competitive values of the trait, which in turn reduces the population density, thereby enabling lesser competitors to stably persist with reduced need to directly compete. Thus, we believe that the pattern is more general and may apply to asymmetric traits more broadly. This robust pattern suggests a comparative, unified explanation to a variety of polymorphic traits in nature.
... adaptation, speciation) overlap in space and time with ecological dynamics (i.e. dispersal, survival, coexistence) (McPeek 1996;Jansen & Mulder 1999;Gillespie 2004;Gavrilets & Vose 2006;McPeek 2008;Gavrilets & Losos 2009;Beardmore et al. 2011;Cornell 2013) creating a new theoretical framework (Etienne et al. 2007;Emerson & Gillespie 2008;Urban et al. 2008;Vellend 2010;Davies et al. 2011;Desjardins-Proulx & Gravel 2012a,b;Pillai & Guichard 2012;Ai et al. 2013). Here, we propose a synthesis that examines this paradigm at various scales of evolutionary (i.e. ...
... Jansen & Mulder 1999;Bonsall et al. 2004;Gudelj et al. 2007;Beardmore et al. 2011;Pillai & Guichard 2012). The shape of the trade-off function is determined by the strength of competition for space.The life history trade-off paradigm is based on the following initial assumptions:(A1) Ecological equivalence (patches): all patches are ecologically equivalent or ecological variations among patches do not impact species abundances (landscape ecology).(A2) ...
The emergence of new frameworks combining evolutionary and ecological dynamics in communities opens new perspectives on the study of speciation. By acknowledging the relative contribution of local and regional dynamics in shaping the complexity of ecological communities, metacommunity theory sheds a new light on the mechanisms underlying the emergence of species. Three integrative frameworks have been proposed, involving neutral dynamics, niche theory, and life history trade-offs respectively. Here, we review these frameworks of metacommunity theory to emphasise that: (1) studies on speciation and community ecology have converged towards similar general principles by acknowledging the central role of dispersal in metacommunities dynamics, (2) considering the conditions of emergence and maintenance of new species in communities has given rise to new models of speciation embedded in the metacommunity theory, (3) studies of diversification have shifted from relating phylogenetic patterns to landscapes spatial and ecological characteristics towards integrative approaches that explicitly consider speciation in a mechanistic ecological framework. We highlight several challenges, in particular the need for a better integration of the eco-evolutionary consequences of dispersal and the need to increase our understanding on the relative rates of evolutionary and ecological changes in communities.
© 2015 John Wiley & Sons Ltd/CNRS.
... Theoretical models show that these trade-offs can alone produce stable community associations (Dislich et al., 2010). Simple models have been extensively studied (Levins and Culver, 1971;Nee and May, 1992;Tilman, 1994;Calcagno et al., 2006;Pillai and Guichard, 2012) and even show coexistence within homogeneous landscapes (Nattrass et al., 2012). The relevance of these results to natural communities depends on the empirical verification within real assemblages. ...
... We hypothesize that the need for functional trade-offs, such as the familiar dispersal-colonization trade-offs (e.g., Ben-Hur et al., 2012;Pillai and Guichard, 2012), can be relaxed when multiple traits and spatial dynamics within heterogeneous landscapes are considered (Higgins and Cain, 2002;Potthoff et al., 2006;Buechi et al., 2009;Dislich et al., 2010;Seifan et al., 2012Seifan et al., , 2013. Ecological processes that maintain diversity for sessile organisms are inherently spatial (Gardner and Engelhardt, 2008): habitats are spatially correlated; competition for resources is most intense among immediate neighbors; dispersal is spatially limited; and most disturbances are spatially discreet, aggregated events. ...
... Theoretical models show that these trade-offs can alone produce stable community associations (Dislich et al., 2010). Simple models have been extensively studied (Levins and Culver, 1971;Nee and May, 1992;Tilman, 1994;Calcagno et al., 2006;Pillai and Guichard, 2012) and even show coexistence within homogeneous landscapes (Nattrass et al., 2012). The relevance of these results to natural communities depends on the empirical verification within real assemblages. ...
... We hypothesize that the need for functional trade-offs, such as the familiar dispersal-colonization trade-offs (e.g., Ben-Hur et al., 2012;Pillai and Guichard, 2012), can be relaxed when multiple traits and spatial dynamics within heterogeneous landscapes are considered (Higgins and Cain, 2002;Potthoff et al., 2006;Buechi et al., 2009;Dislich et al., 2010;Seifan et al., 2012Seifan et al., , 2013. Ecological processes that maintain diversity for sessile organisms are inherently spatial (Gardner and Engelhardt, 2008): habitats are spatially correlated; competition for resources is most intense among immediate neighbors; dispersal is spatially limited; and most disturbances are spatially discreet, aggregated events. ...
Access to critical resources for sessile organisms, such as light, water, and nutrients, is determined by the variability of landscape patterns, species traits and environmental drivers. We have studied the interactions among these variables for tidal marshes where sediment deposition and erosion, sea level rise and disturbances can shift the elevation of the landscape and alter the structure of the herbaceous plant community. A spatially-explicit model for 16 herbaceous species with differing life-history traits governing growth, fecundity, dispersal, and mortality was compared with field data from ongoing studies of a marsh community within the Potomac River estuary. Comparisons of patterns of species richness and relative abundances with field data were used to verify model adequacy. Results of 40-y simulations for different environmental change scenarios (sediment deposition, sea level rise, variable weather conditions and disturbances) showed that species richness patterns were remarkably stable. Species abundances, however, varied dependent on model scenario and life-history traits. Species coexistence was found to be enhanced by differences in habitat preferences and dispersal-limited patterns of aggregation which elevated negative intraspecific interactions. This new model highlights the importance of spatial processes in maintaining biodiversity even in the absence of absolute trade-offs, a necessity in non-spatial models.
