Diversity and community assembly structure in canopy jumping spiders (Araneae: Salticidae) across a land use gradient in Jambi, Sumatra

Canopy arthropods function as important predators and pollinators and constitute the majority of biomass and biodiversity in tropical ecosystems. However, rainforest canopies are threatened, particularly in Southeast Asia, by the rapid transformation of lowland rainforest to monocultures of oil palm (Elaeis guineensis) and rubber (Hevea brasiliensis). The study aims to investigate the effects of these transformation processes on the diversity and community assembly structure of canopy jumping spiders (Araneae: Salticidae). Spiders are sensitive in their distribution and assembly structure towards disturbances and alterations in the vegetation, thus they are useful organisms to study biodiversity across changing environments. As many of the investigated spiders are either not formally described to taxonomy or need to be determined by experts, we use morphology-based identification to morphospecies, in order to assess biodiversity. Biodiversity patterns are tested for correlation against a set of environmental variables, describing changes in vegetation complexity, land use intensity and microclimate, caused by rainforest transformation. In a community phylogenetics approach, we will calculate the Net Relatedness Index (NRI) and Nearest Taxon Index (NTI), two commonly used metrics, based on the phylogenetic distance of species in a community, which allow to reveal potential influences of rainforest transformation on the community assembly structure. This study will help to understand how agricultural expansion in Southeast Asia affects biodiversity and community assembly of jumping spiders and might hint to the impact on spiders and their associated ecosystem function as arthropod top predators, in general.