Multiscale effects of habitat changes on diversity of rainforest snakes

Abstract

Snake response to habitat changes is frequently investigated at the species level, but it is still poorly known how snakes respond to habitat changes at the community level and at which spatial scale. Here, we used a multi-model inference approach to evaluate the effects of local and landscape composition (percentage of forest cover and silviculture) and habitat fragmentation (number of forest patches and total edge) on species, functional, and phylogenetic diversity of snake communities in tropical fragmented landscapes. Additionally, we tested whether silviculture acted as an environmental filter for snakes. Species and functional diversity responded primarily to landscape elements: species richness, abundance, and functional diversity decreased with deforestation. In addition, species richness and abundance increased with the proportion of forest and the number of patches in the landscape. In contrast, phylogenetic diversity was driven by the local habitat composition. Although habitat types did not filter entire clades and functional groups, each species tended to have a co-occurring species with similar traits (at landscape level) and a close relative (at both levels) in impacted habitats. In contrast, the co-occurrence of close relatives and functionally similar species was avoided in the native forest. Our findings indicate that snake responses to habitat changes occur on multiple scales and highlight the importance of conserving native forests to maintain multiple components of biodiversity. Strategies for conserving snake diversity in tropical fragmented landscapes should therefore consider management practices at both the local and landscape scales.