Rethinking Community Assembly through the Lens of Coexistence Theory

TLDR

Research on competitive interactions in community assembly has recently revived, yet limitations of isolated approaches leave a poor understanding of which niche axes and traits shape competition and community structure. The study aims to combine contemporary coexistence theory with three empirical approaches to better determine which niche axes and traits govern plant community assembly. The authors evaluate experimental manipulations of abiotic/biotic environments, trait‑phylogeny‑environment relationships, and frequency‑dependent population growth using contemporary coexistence theory emphasizing stabilizing niche differences and relative fitness differences. Their analyses reveal that all three empirical approaches indicate strong influences of stabilizing niche differences and fitness differences on plant community assembly outcomes.

Abstract

Although research on the role of competitive interactions during community assembly began decades ago, a recent revival of interest has led to new discoveries and research opportunities. Using contemporary coexistence theory that emphasizes stabilizing niche differences and relative fitness differences, we evaluate three empirical approaches for studying community assembly. We show that experimental manipulations of the abiotic or biotic environment, assessments of trait-phylogeny-environment relationships, and investigations of frequency-dependent population growth all suggest strong influences of stabilizing niche differences and fitness differences on the outcome of plant community assembly. Nonetheless, due to the limitations of these approaches applied in isolation, we still have a poor understanding of which niche axes and which traits determine the outcome of competition and community structure. Combining current approaches represents our best chance of achieving this goal, which is fundamental to conceptual ecology and to the management of plant communities under global change.