The role of plasticity and stochasticity in coexistence

Abstract

Species coexistence in ecological communities is a central feature of biodiversity. Different concepts, i.e., contemporary niche theory, modern coexistence theory, and the unified neutral theory, have identified many building blocks of such ecological assemblies. However, other factors, such as phenotypic plasticity and stochastic inter‐individual variation, have received little attention, in particular in animals. For example, how resource polyphenisms resulting in predator–prey interactions affect coexistence is currently unknown. Here, we present an integrative theoretical–experimental framework using the nematode plasticity model Pristionchus pacificus with its well‐studied mouth‐form dimorphism resulting in cannibalism. We develop an individual‐based model that relies upon synthetic data based on our empirical measurements of fecundity and polyphenism to preserve demographic heterogeneity. We demonstrate how the interplay between plasticity and individual stochasticity result in all‐or‐nothing outcomes at the local level. Coexistence is made possible when spatial structure is introduced.

Competitor-induced plasticity modifies the interactions and predicted competitive outcomes between annual plants

“…Our results also illustrate the possibility that the history of interactions a species experiences may influence the strength of the competition affecting its growth in the future. One research direction emerging from our work would involve building mathematical models where each individual has a "memory" (encoded by their morphology) of the competition they have experienced [63,66,67,68,69,70]. A similar approach has been proposed in the context of trait-based priority effects, in which the strength of species interactions shifts as a function of trait values which themselves depend on community composition [71,72].…”