Landscape-scale drivers of mammalian species richness and functional diversity in forest patches within a mixed land-use mosaic
Yvette C. Ehlers Smith, David A. Ehlers Smith, Tharmalingam Ramesh, Colleen T. Downs
Abstract
We estimated the influence of habitat fragmentation characteristics (patch size, isolation and number of neighbouring patches), habitat and land management types at the community level, specifically, on species richness, functional- α (alpha), guild- and β (beta) diversity of forest and dense bush habitat patches in southern KwaZulu-Natal Province, South Africa. We used mammal camera-trap data from 245 survey points across 157 habitat patches. We partitioned β diversity-change (βtotal) into its nestedness (βnestedness) and turnover (βturnover) components. Species turnover was the dominant component of species β diversity, while nestedness was the dominant component of functional β diversity. Carnivore and insectivore diversity significantly decreased with increasing isolation from large patches. Patch size did not influence species-, functional- or guild diversity. We found that the number of neighbouring patches nested within the mixed land-use matrix were important drivers of functional- and species α diversity, carnivore- and herbivore diversity. Fragmentation characteristics alone did not explain the patterns of diversity tested, but habitat and land management type were important factors for all diversity indices. We recommend incentivised protection for privately owned forest patches, as they act as stepping stones for movement of forest-associated mammals throughout the landscape. Furthermore, we emphasise the importance of habitat quality and of effective management of forest in mixed land-use mosaic landscapes to prevent further degradation.