Ecology of small mammals across a strong environmental gradient in southern South America

Abstract

Abundances of species of small mammal in typical southern-Valdivian, temperate rainforest decline and those of more xeric-adapted species of Patagonian steppe increase across a major environmental gradient in southern Chile. Despite heterogeneous and skewed distributions of all individual species across this transition, community characteristics including species richness, community evenness, biomass of trophic groups (animalivores, folivores, fungivores, granivores, omnivores), and total biomass of rodents do not change significantly across this gradient. Across this transition, local (ecological) processes evidently compensate for geographical (historical) constraints, yielding remarkably constant community dynamics. Species richness of small mammals in this region appears limited by availability of resources rather than the pool of species available to colonize a site.