Patterns and predictors of mammalian taxonomic and functional species diversity in naturally fragmented Southern Mistbelt Forests in South Africa

Anthropogenic land-use change generally affects species movement, resource use, beta diversity and causes declines and changes in species diversity. In Africa, forest mammals are strongly affected by such anthropogenic factors. Functional diversity metrics have been used to understand changes in the landscape and how these affect species communities. Our study aimed to evaluate the response of forest mammal's functional diversity and species richness to factors such as forest patch size and isolation distance, forest structural complexity, and landscape configuration. We examined this in selected naturally fragmented Southern Mistbelt Forests in South Africa. Following camera-trapping of non-volant forest mammals, we used linear mixed-effects models to assess the response of functional diversity indices and species richness to patch size, forest structural complexity, isolation and neighboring patches. We calculated β-diversity and partitioned it into its additive components of species spatial turnover (βsim) and nestedness (βnes). Patch size and forest structural complexity showed a relationship with most of the functional diversity indices. Patch size often had a positive relationship with higher species diversity. The more fragmented a landscape was, the diversity of species decreased, implying difficulty of movement between patches and the inability to support viable populations. Patch size was an important factor in understanding mammalian species' β-diversity in a disjunct landscape. We showed the importance of forest structural complexity as it promoted functionally diverse mammalian communities and enhanced ecosystem functioning. Conservation of larger, structurally diverse forest patches in the naturally fragmented Southern Mistbelt Forests will promote forest mammalian communities persistence.