Reorganization of taxonomic, functional, and phylogenetic ant biodiversity after conversion to rubber plantation

Agricultural activity associated with habitat conversion is a major driver of biodiversity loss across the tropics. The decline of species richness is a common outcome of conversion to agricultural land use, but the associated changes in functional and phylogenetic diversities, and spatial patterns of beta diversity, are not well understood. These patterns may shed light on underlying ecological processes that are of both basic and applied interest; for example the relative roles of stochastic assembly, ecological filtering, and competition in structuring ecological communities as well as broader consequences for ecological functioning in agroecosystems. Here we investigate the effects of conversion to rubber plantation (Hevea brasiliensis), a rapidly spreading agroecosystem in Southeast Asia, on leaf-litter ant taxonomic, functional, and phylogenetic diversities at local and among-sites scales in Xishuangbanna, Southeast China. We found a sharp decline of ant species richness in rubber plantations compared with nearby forest habitat, with low beta diversity indicating spatial homogeneity of communities in rubber plantations. In addition, patterns of both functional alpha and beta diversities suggested the emergence of a functionally distinct ant community in the agroecosystem compared to the forest habitats. These results support a role of ecological filtering in structuring the taxonomic and functional composition of both rubber and forest habitats. In contrast, changes in phylogenetic diversity were modest and not significantly different from random expectations despite strong phylogenetic signal of functional traits. This study highlights the need for a pluralistic approach to characterizing the loss of biodiversity in agroecosystems, as well as understanding the underlying mechanisms of community assembly driving this biodiversity loss.