Species Interactions Limit the Predictability of Community Responses to Environmental Change

Abstract

Predicting how ecological communities will respond to environmental change is challenging but highly relevant in this era of global change. Ecologists commonly use current spatial relationships between species and environmental conditions to make predictions about the future. This assumes that species will track conditions by shifting their distributions. However, theory and experimental evidence suggest that species interactions prevent communities from predictably tracking temporal changes in environmental conditions on the basis of current spatial relationships between species and environmental gradients.We tested this hypothesis by assessing the dynamics of protist species in replicated two-patch microcosm landscapes that experienced different regimes of spatial and temporal environmental heterogeneity (light vs. dark). Populations were kept in monocultures or polycultures to assess the effect of species interactions. In monocultures, abundances were predictable on the basis of current environmental conditions, regardless of whether the populations had experienced temporal environmental change. But in polycultures, abundances also depended on the history of the environmental conditions experienced. This suggests that because of species interactions, communities should respond differently to spatial versus temporal environmental changes. Thus, species interactions likely reduce the accuracy of predictions about future communities that are based on current spatial relationships between species and the environment.

Biotic interactions structure zooplankton metacommunity dynamics following a summer heatwave

“…This in itself should not be surprising given the central role that species play in our understanding of community ecology (Clements 1916;Lotka 1922;Volterra 1926;Hutchinson 1957). Indeed, theory (Ives & Cardinale 2004;Thompson & Gonzalez 2017) and experimental evidence (Davis et al 1998;Brown & Vellend 2014;Alexander et al 2015;Thompson et al 2021) suggest that biotic interactions lead to context-dependent dynamics so that the composition of communities is rarely predictable purely based on environmental conditions. Still, most classic metacommunity theory only includes simple biotic interactions which do not result in context dependence (Loreau et al 2003;Gonzalez et al 2009).…”

“…Competition and predation, for example, may prevent a population from establishing and growing when environmental conditions would otherwise be suitable (Gilman et al 2010;Brown & Vellend 2014). Thus, biotic interactions are a primary reason why communities that experience the same environmental conditions may differ in composition (Davis et al 1998;Ives & Cardinale 2004;Thompson et al 2021). Biotic interactions are a critical driver in successional dynamics that are common in forest communities (Clements 1916).…”

“…More recent theory highlights the importance of biotic interactions, and makes the prediction that biotic interactions should reduce species sorting and lead to non-random patterns of species co-occurrence across space and time that are unrelated to local environmental conditions (Thompson et al 2020). When communities experience periods of extreme conditions, such as during a heatwave, experimental evidence suggests that biotic interactions may prevent the community from returning to its initial compositional state Thompson et al (2021).…”

Documenting the impacts of increasing salinity in freshwater and coastal ecosystems: Introduction to the special issue

“…We know that species occur within communities and ecosystems, and that the interaction between them can modulate the sensitivity of individual species to stressors (Baillard et al 2020; Thompson et al 2021). Kefford et al (2021) and Arnott et al (2022) call for more community‐based toxicity tests and coordinated mesocosm studies that account for species interactions rather than single species toxicity tests performed in laboratories when salinity standards for the protection of aquatic ecosystems are developed.…”

Biotic interactions structure zooplankton metacommunity dynamics following a summer heatwave

“…Competition and predation, for example, may prevent a population from establishing and growing when abiotic conditions would otherwise be suitable (Brown and Vellend 2014). Thus, biotic interactions are a primary reason why communities that experience the same abiotic conditions may differ in composition (Davis et al 1998;Ives and Cardinale 2004;Thompson et al 2021). Despite this, most classic metacommunity theory (e.g., Loreau et al 2003;Leibold et al 2004) is expressed in simple terms (competition is the only species interaction) and employs the assumption that the strength of competition is equal amongst all individuals and species.…”