Rethinking plant community theory

TLDR

Plant communities have traditionally been viewed as either random collections or organismal entities, yet no comprehensive theory integrates stochasticity, abiotic tolerances, and biotic interactions. The authors argue that formal community theory should explicitly incorporate facilitation and indirect effects among competitors, rejecting strict individualism to better explain spatial variation, synthesize predictive dynamics, and model community responses to global change. They introduce the integrated community concept, positing that natural plant communities span from highly individualistic to highly interdependent based on synergistic interactions among stochastic processes, species tolerances, direct plant interactions, and indirect trophic interactions. Their analysis shows that these interactions do not support the traditional individualistic perspective.

Abstract

Plant communities have traditionally been viewed as either a random collection of individuals or as organismal entities. For most ecologists however, neither perspective provides a modern comprehensive view of plant communities, but we have yet to formalize the view that we currently hold. Here, we assert that an explicit re‐consideration of formal community theory must incorporate interactions that have recently been prominent in plant ecology, namely facilitation and indirect effects among competitors. These interactions do not suppport the traditional individualistic perspective. We believe that rejecting strict individualistic theory will allow ecologists to better explain variation occurring at different spatial scales, synthesize more general predictive theories of community dynamics, and develop models for community‐level responses to global change. Here, we introduce the concept of the integrated community (IC) which proposes that natural plant communities range from highly individualistic to highly interdependent depending on synergism among: (i) stochastic processes, (ii) the abiotic tolerances of species, (iii) positive and negative interactions among plants, and (iv) indirect interactions within and between trophic levels. All of these processes are well accepted by plant ecologists, but no single theory has sought to integrate these different processes into our concept of communities.