metacommunity

Metacommunity is an ecological concept describing a set of local communities that are spatially connected by the dispersal of multiple species across a landscape. In this framework, the composition of each local community results from the interplay between local processes such as competition, predation, and environmental filtering, and regional processes such as immigration and dispersal. The metacommunity perspective highlights how regional connectivity shapes local diversity and species turnover across space and time.

Dispersal and connectivity rank as central factors in metacommunity dynamics. The framework emphasizes that local communities do not exist in isolation; rather, colonization and extinction events, immigration, and movement of individuals across patches influence community composition and persistence. This leads to patterns of beta diversity, where turnover in species composition across sites reflects both local interactions and regional processes.

Several governing paradigms have been described. Patch dynamics emphasizes discrete habitat patches with colonization-extinction dynamics and competitive interactions. Species sorting stresses environmental heterogeneity and trait-based filtering of species across patches. Mass effects focuses on the influence of high dispersal, which can import species into suboptimal patches and alter local communities. Neutral metacommunity theory posits stochastic assembly under functional equivalence among species, highlighting random dispersal and drift.

Real systems often show a mixture of these processes, with their relative importance varying with dispersal rates, habitat connectivity, and patch quality. Researchers use comparisons of local and regional diversity, beta diversity metrics, and metacommunity models to infer underlying processes, along with experiments that manipulate dispersal and network approaches to quantify connectivity.

Metacommunity concepts inform conservation and landscape planning by emphasizing connectivity and habitat mosaics, reserve design, and the maintenance of regional biodiversity in fragmented landscapes. They are related to, but distinct from, metapopulation theory, which centers on extinction and colonization of populations within patches rather than cross-taxa community dynamics.