Drivers for plant species diversity in a characteristic tropical forest landscape in Bangladesh

The importance of understanding biotic patterns in managed tropical landscapes is increasingly recognised. Bangladesh is a country with a long human land-use history and constitutes almost a blind spot in vegetation science on the landscape scale. Here, we analyse patterns and drivers of plant species richness and community composition along a land-use intensity gradient in a forest landscape including tea gardens, tree plantations and nature reserves (Satchari Reserved Forest) based on multivariate approaches and variation partitioning. We find richness as well as composition of tree and understory species to directly relate to a disturbance gradient that reflects protection status and elevation. This is astonishing, as the range in elevation (70 m) is small. Topography and protection remain significant drivers of biodiversity after correcting for human disturbances. While tree and non-tree species richness were positively correlated, they differ considerably in their relation to other environmental or disturbance variables as well as in the spatial richness pattern. The disturbance regime particularly structures tree species richness and composition in protected areas. We conclude by highlighting the importance of explicitly integrating human–biosphere interactions in any nature protection strategy for the study region.