Boosting freshwater fish conservation with high-resolution distribution mapping across a large territory.

The lack of high-resolution distribution maps for freshwater species across large scales fundamentally challenges biodiversity conservation worldwide. Here, we propose a simple framework to delineate the distributions of freshwater fishes in a high-resolution drainage map using stacked species distribution models and expert-based information. Applying this framework to the whole Chinese freshwater fish fauna (+1600 species), we produced high-resolution biodiversity patterns and revealed potential conflicts between biodiversity and anthropogenic disturbances. The correlations between spatial patterns of biodiversity facets (species richness, endemicity and phylogenetic diversity) were all significant but idiosyncratic (r = 0.43-0.98, P < 0.001). Areas with high values of different biodiversity facets overlapped with anthropogenic disturbances. Existing protected areas, covering 22% of China's territory, were shown to protect 25-29% of fish habitats, 16-23% of species, and 30-31% of priority conservation areas. Moreover, 6-21% of the species are still completely unprotected. These results suggest the need for extending the network of protected areas to ensure the conservation of China's freshwater fish biodiversity and the goods and services it provides to humans. Specifically, middle to low reaches of large rivers and their associated lakes from Northeast to Southwest China host the most diverse species assemblages and should be the target of future expansions of the network of protected areas. More generally, the framework we propose to draw high-resolution biodiversity maps combining species occurrence data and expert knowledge on species distribution provides an efficient way to unlock protected area designs regardless of the ecosystem, taxonomic group or world area considered. This article is protected by copyright. All rights reserved.