Biodiversity and ecosystem stability across scales in metacommunities

The autors used a dynamical model of competitive metacommunities to study the relationships between species diversity and ecosystem variability across scales. They derived analytic relationships under a limiting case; extending theses results to more general cases with numerical simulations. Their model shows that, while alpha diversity decreases local ecosystem variability, beta diversity generally contributes to increasing spatial asynchrony among local ecosystems. Consequently, both alpha and beta diversity provide stabilizing effects for regional ecosystems, through local and spatial insurance effects respectively. They further show that at the regional scale, the stabilizing effect of biodiversity increases as spatial environmental correlation increases. Finally, their findings have important implications for understanding the interactive effects of global environmental changes (e.g. environmental homogenization) and biodiversity loss on ecosystem sustainability at large scales.