The neglected otters in China: Distribution change in the past 400 years and current conservation status

Freshwater biodiversity is currently facing critical threats worldwide. As top predators, otters are indicator species of ecosystem health, and flagship species for conservation in freshwater ecosystems. Three otter species – Lutra lutra, Aonyx cinereus, and Lutrogale perspicillata – exist in China. They were once widely distributed but have experienced dramatic decline in the late 20th century, being listed as Class II protected animals in China. We searched in gazetteers, publications, online news, museum specimens, and camera trapping databases, and conducted questionnaire surveys to obtain otter records to reconstruct the historical (1550–1950), recent (1950–2000), and current (post-2000) distribution maps of otters in China. Unlike many other mammal species, otters' range did not contract during 1550–1950. Otters' recent and current distributions were comparable or even surpassed their historical ranges. However, applying rigorous verification criteria, only 57 sites in China were confirmed with otter occurrence since 2000. The potential distribution of L. lutra was mainly on the Tibetan Plateau and in northeast China, whereas only small and sparse patches remained in southeast China, where otters were frequently recorded in historical gazetteers. Although being endangered, otters have been neglected in China, with few research projects and no project funded by National Natural Science Foundation of China. Consequently, even wildlife experts have poor knowledge of otters. Surveys and specific research are urgently needed for otters in China. Public education is also advocated to raise awareness of otter conservation. Without sound information generated from research and urgent conservation actions, otter species will remain severely threatened in China.