Building modern coexistence theory from the ground up: The role of community assembly

• Published in: Ecology letters Vol. 26; no. 11; pp. 1840 - 1861
• Main Authors: Spaak, Jurg W., Schreiber, Sebastian J.
• Format: Journal Article
• Language: English
• Published: Paris Blackwell Publishing Ltd 01.11.2023
• Subjects: Assembly; Coexistence; Growth rate; invasion growth rates; Invasive species; Mathematical models; modern coexistence theory; niche and fitness differences; permanence theory; Rare species; storage effect
• ISSN: 1461-023X; 1461-0248
• DOI: 10.1111/ele.14302

Modern coexistence theory (MCT) is one of the leading methods to understand species coexistence. It uses invasion growth rates—the average, per‐capita growth rate of a rare species—to identify when and why species coexist. Despite significant advances in dissecting coexistence mechanisms when coexistence occurs, MCT relies on a ‘mutual invasibility’ condition designed for two‐species communities but poorly defined for species‐rich communities. Here, we review well‐known issues with this component of MCT and propose a solution based on recent mathematical advances. We propose a clear framework for expanding MCT to species‐rich communities and for understanding invasion resistance as well as coexistence, especially for communities that could not be analysed with MCT so far. Using two data‐driven community models from the literature, we illustrate the utility of our framework and highlight the opportunities for bridging the fields of community assembly and species coexistence. Modern coexistence theory (MCT) is limited by its dependence on the naive invasion growth rate criterion. We extend the applicability of MCT by using permanence theory. We use this newly developed method to gain new insights into community coexistence and its limits.