Abstract
The metacommunity concept has greatly advanced our understanding of how spatial dynamics shape ecological communities. To date, this framework has emphasized discrete differences between mechanisms structuring metacommunities (e.g. niche vs. neutral), despite the recognition that assembly processes are continuous. Here we present a fundamental reconception of the framework that explicitly links local coexistence theory to metacommunity theory and allows for a continuous range of competitive metacommunity dynamics. These dynamics emerge from the underlying processes that shape the dynamics of ecological communities: 1) density-independent responses to abiotic conditions, 2) density-dependent biotic interactions, and 3) dispersal. We also incorporate stochasticity in the demographic realization of each of these processes. The traditional metacommunity archetypes exist as discrete regions within this space, but our framework highlights a range of dynamics that are missed in classic metacommunity theory. We formalize this framework using a simulation model that explores the full range of competitive metacommunity dynamics by varying the strength of the underlying processes. We illustrate how the different processes interactively shape the diversity, functioning, and stability of metacommunities. This process-based framework extends the rich history of metacommunity ecology and can be used to generate testable hypotheses on the processes structuring metacommunities in nature.
Footnotes
Statement of authorship: This project was conceived at the sTURN working group, of which all authors are members. PLT developed the framework and model with input from all authors. PLT wrote the model code. PLT and LMG performed the simulations. PLT produced the figures and wrote the first draft with input from LMG and JMC. All authors provided feedback and edits on several versions of the manuscript.
Data accessibility: All code for running the simulation model and producing the figures will be archived on Zenodo upon acceptance and the doi will be included at the end of the manuscript.