Impacts of anthropogenic habitat modification on mammalian diversity in the Mau Forest Complex, Kenya

Abstract

Habitat destruction is a major driver of biodiversity loss, especially in the tropics. We investigated changes in the diversity and occupancy of forest-dwelling mammals in response to habitat loss, alteration, and degradation at the Mau Forest Complex (MFC), southwestern Kenya. Using a systematic camera trapping grid, we estimated patterns of mammalian diversity, occupancy of small carnivores, and detection rates of functional mammalian groups across three habitat types (primary forests, secondary forests, and cultivated habitats). Between March 2019 and October 2021, 246 camera traps were deployed across 181 locations representing 5509 sampling days, resulting in 47,345 images of 52 mammalian species in nine mammalian orders. Alpha diversity differed among treatments, with primary forests having the highest diversity, and cultivated habitats the lowest, though results were not statistically significant. Beta diversity differed significantly among treatments, indicating differences in community composition as well as species richness. Overall occupancy for small carnivores was highest in primary forests and lowest in cultivated habitats, with some species specializing in primary forests while others were able to occupy more degraded habitats. Among functional groups, detection rates only differed significantly for large rodents, primates, and ungulates. Our results indicate that although functional groups and species may respond differently to habitat loss and alteration at the MFC, overall species diversity of specialist mammals was highest in the less-disturbed primary forests. Specialist, forest-dependent species are likely most affected by human activities, making them especially vulnerable to habitat loss at the MFC.