Diversity and assemblage structure of bark-dwelling spiders in tropical rainforest and plantations under different management intensities in Xishuangbanna, China

1. In tropical Southeast Asia, large-scale establishment of forest plantations has reduced forest diversity and altered arthropod assemblages by changing plant communities and ecological properties. Few studies address the impacts of forest change on important predatory groups on tree trunks. 2. We compared spider assemblages on tree trunks in natural forests and three forest plantation types in the Xishuangbanna area of southwestern China, to determine how tropical forest management influences bark-dwelling spider composition. Spiders were sampled using trunk traps in tropical seasonal rain forests (TSRF), rubber plantations (RP), rubber-tea mixtures (RTM) and Aporosa yunnanensis plantations (AYP). 3. Spider species composition differed between TSRF and forest plantations. Canopy cover in both seasons and grass cover and shrub cover in the dry season well explained species assemblages. Spider diversity between TSRF and forest plantations differed more distinctly in the rainy season. AYP had an intermediate level of disturbance, which was associated with highest species richness, whereas TSRF had the highest beta diversity. The mean number of individuals was the highest in RP, but species richness and beta diversity were the lowest. 4. An intermediate level of disturbance increased alpha diversity of bark-dwelling spiders, whereas intensive management that altered vegetation structure had adverse effects on these spiders. Preservation or enhancement of surface vegetation in RP may maintain or increase species richness of bark-dwelling spiders. The highest beta diversity of the TSRF indicated that undisturbed natural forests better conserved regional spider diversity than plantations.