Integrating eco‐evolutionary dynamics and modern coexistence theory

Abstract

Community ecology typically assumes that competitive exclusion and species coexistence are unaffected by evolution on the time scale of ecological dynamics. However, recent studies suggest that rapid evolution operating concurrently with competition may enable species coexistence. Such findings necessitate general theory that incorporates the coexistence contributions of eco‐evolutionary processes in parallel with purely ecological mechanisms and provides metrics for quantifying the role of evolution in shaping competitive outcomes in both modelling and empirical contexts. To foster the development of such theory, here we extend the interpretation of the two principal metrics of modern coexistence theory—niche and competitive ability differences—to systems where competitors evolve. We define eco‐evolutionary versions of these metrics by considering how invading and resident species adapt to conspecific and heterospecific competitors. We show that the eco‐evolutionary niche and competitive ability differences are sums of ecological and evolutionary processes, and that they accurately predict the potential for stable coexistence in previous theoretical studies of eco‐evolutionary dynamics. Finally, we show how this theory frames recent empirical assessments of rapid evolution effects on species coexistence, and how empirical work and theory on species coexistence and eco‐evolutionary dynamics can be further integrated.

Trait adaptation enhances species coexistence and reduces bistability in an intraguild predation module

“…This extinction risk was strongly reduced with increasing speed of trait adaptation. Additionally, in line with previous studies (Vasseur et al, 2011;Yamamichi et al, 2022), biomass-trait feedbacks drive species trait values to vary over time at higher enrichment, which creates new opportunities for coexistence that do not exist for any fixed trait values (Figure S16). Thus, in the adaptive IGP model, coexistence was strongly promoted as species were able to adapt to suitable trait values at a steady state enabling, for example, indirect evolutionary rescue.…”

Different measures of niche and fitness differences tell different tales

“…While conceptually straightforward, there are many different methods to compute niche and fitness differences (Godwin et al 2020, Spaak and De Laender 2020), with new methods still being developed for competition for mutualists (Johnson 2021), resource competition (Koffel et al 2021), plant–soil feedbacks (Kandlikar et al 2019), multitrophic communities (Spaak et al 2021b), spatial explicit communities (Luo et al 2022) or communities with evolving species (Yamamichi et al 2022). Few of these methods have been applied extensively to experiments, while others have been rarely used (Buche et al 2022) and little is known about their practical usability .…”

Metabolic evolution in response to interspecific competition in a eukaryote

“…Predicting how species evolve in communities remains a formidable challenge (51)(52)(53). Interactions among multiple species can diffuse competition (54), weakening selection between any pair of competitors (55,56).…”