Alpha, beta and gamma diversity in relatively natural, mixed and transformed landscape scenarios

Biodiversity losses and biotic homogenisation associated with human‐induced land‐cover changes are key issues for ecology. However, the effects of human‐caused land‐use changes on biodiversity change at the landscape scale are not well understood. Combining the PREDICTS global biodiversity database with MODIS satellite‐based land cover from 2001 to 2013, we created three landscape modification scenarios – relatively natural, partially modified (mixed, e.g. mixtures of crops and natural remnants) and fully modified (transformed, e.g. urban and plantation mosaics) and estimated the landscape‐scale alpha, beta and gamma diversity associated with each. Our results reveal that landscape‐scale modification from relatively natural landscapes to mixed landscapes increases the variety of ecosystem types and modification levels, hence increasing the variety of ecological communities (beta diversity) and maintaining landscape‐level diversity (gamma), despite reductions in average local‐level diversity (alpha). However, total transformation (from mixed towards completely transformed landscapes) causes a decline in both alpha and gamma diversity. Our results highlight that anthropogenic modification can potentially increase some elements of biodiversity while decreasing others and that high levels of landscape‐scale diversity can be maintained within mixed landscapes.