Non-random defaunation: Multidimensional dark diversity demonstrates pervasive mammal community incompleteness in China’s protected area network

This approach overlooks dark diversity—the species absent from biogeographically suitable habitats and their associated evolutionary and ecological roles. We used a dataset comprising 7.4 million camera-trap days across 199 nature reserves in China to assess the taxonomic, phylogenetic, and functional dark diversity of medium- and large-sized mammals.

Biogeographic null models and Bayesian hierarchical models showed that mammal communities in these reserves were, on average, 56% incomplete. Dark diversity across all three dimensions was highest in southern and east-central China, despite these regions having the highest observed species richness. Null-model analyses indicated that mammal losses in southern China were non-random, with disproportionate losses of evolutionary lineages and functional trait space.