Fragment configuration or environmental quality?: Understanding what really matters for the conservation of native mammals in the Atlantic Forest of Argentina

Abstract

The fragmentation of natural environments is one of the most important threatsto biodiversity and involves changes in landscape configuration and habitatquality. The Atlantic Forest of South America has been highly fragmented,which creates concern for the conservation of its biodiversity. We evaluated theeffects of forest loss and fragmentation on the terrestrial mammal assemblageof the Atlantic Forest of Misiones, Argentina. The area still contains largefragments and a forest cover >50%. We evaluated the effect of theconfiguration of the fragments (area, isolation) and the quality of theenvironment surrounding them (% of forest, land uses, poaching). We sampledmammal assemblages with camera-traps. We used generalized linear models,with the number of species in smaller forest fragments (49 stations) and thedifference in their composition to that of the largest forest fragment (controlsituation; 53 stations) as response variables. Species richness in the fragmentsincreased with the proportion of forest in their surroundings and decreased withthe distance to population sources. The dissimilarity of the assemblages ofsmaller fragments to those of the largest fragment increased with forestdisturbance and by the contrast of the land uses (e.g., annual crops)surrounding the fragments. We modeled and mapped these effects, which canbe used as spatially explicit planning tools for the conservation of the mammalassemblage in this landscape. The effect of fragmentation on the mammalassemblage is mediated by both anthropic effects that affect the quality of theenvironment and by the spatial configuration of fragments in the landscape.