Weak dispersal and landscape size inevitably promote local biodiversity in heterogeneous metacommunities of competing species.

Weak dispersal and larger landscape size promote local species richness in heterogeneous metacommunities of competing species.

• Why it matters: Understanding the factors that sustain biodiversity in spatially structured habitats is crucial for conservation and ecological management, especially in fragmented landscapes.
• What they did: Using analytical approximations of spatial Lotka-Volterra competition models, the study links local species persistence to the balance of total density and exclusion rate, and tests predictions with numerical simulations and long-term data from a natural microcrustacean metacommunity.
• The result: Results show that weak dispersal increases local species richness, especially with more patches, and landscape size consistently promotes coexistence, while dispersal effects diminish under strong competition and dispersal conditions.