Factors outside privately protected areas determine mammal assemblages in a global biodiversity hotspot in the Andes

Abstract

Privately protected areas with voluntary forest protection are promoted as an innovative solution for biodiversity conservation across the globe, particularly in regions where high biological diversity is threatened by agricultural expansion and human disturbance such as the tropical Andes. Colombia alone has over 2000 privately protected areas, but how well private reserves achieve conservation goals is largely unknown. To understand the attributes of reserves that determine success and the types of species conserved, we evaluated regional diversity of medium and large mammals with camera trapping over two years in the western Andes of Colombia. We examined how mammal occupancy was influenced by the size and land use of privately protected areas, landscape-scale variables, and anthropogenic disturbance. We used a multi-species hierarchical framework to assess responses of species and functional groups to environmental covariates. We found that forest in this reserve network retains a diverse mammal assemblage, but low occurrence and restricted species distributions suggest high vulnerability. Forest-restricted species and large species had higher occupancy in larger sites and sites with a higher proportion of forest, regardless of whether a site was designated as a reserve. However, landscape-level measures of connectivity and human disturbance were the strongest predictors of occupancy. Our research indicates that conservation of biodiversity within reserve networks in the Andes will be effective only if these efforts are linked to landscape-level conservation initiatives that conserve large areas of native forest and limit human disturbance across the landscape.