Effects of habitat amount and fragmentation per se on mammals in a highly fragmented Colombian region

The effects of fragmentation on biodiversity are debated. Some studies find positive effects, while others link it to biodiversity loss. “Fragmentation per se” refers to habitat fragmentation independently of habitat loss or control of its effect, which ultimately relates more to how patches are organized (habitat configuration) on biodiversity. We tested the habitat amount hypothesis that postulates that habitat cover would be the main factor determining species diversity. We evaluated the effects of habitat amount and fragmentation per se of tropical dry forest in the Colombian Caribbean region on the taxonomic and functional species richness of medium- to large-bodied mammals. For this, we evaluated 34 landscapes with forest cover ranging from 5–90%. We calculated composition (forest cover) and configuration (forest edge density, number of patches, mean patch area) landscape structure metrics. In each landscape, we calculated total taxonomic richness, forest-dependent species richness, non-forest-dependent species richness, and functional richness using camera trap records. We found that the edge density had a positive effect for on total species richness and moderate positive effects on non-forest-dependent species, while, forest-dependent species richness was negatively affected by the number of patches and positively by forest cover and we found no significant or moderate effects on functional richness. These findings suggest that conservation efforts should focus on preserving and increasing the total amount of habitat and also take into account the configuration of the tropical dry forest in the Colombian Caribbean.