Taxonomic and spatiotemporal patterns and ecological correlates of new mammal distribution records in China

Aim: Species' geographic distributions are central to research in biogeography, macroecology, and conservation biology. However, incomplete or inaccurate knowledge about species' spatiotemporal distribution ranges—known as the Wallacean shortfall—hampers our understanding of biodiversity patterns and processes. We aim to investigate the taxonomic, spatiotemporal and biogeographical patterns of new mammal distribution records in China and identify the species-level and provincial-level drivers underlying the discoveries. Location: China. Methods: We compiled 192 peer-reviewed papers published from 2001 to 2023 that reported the first provincial-level new occurrence records for 150 mammal species in 26 families across 7 orders. We assessed the effects of species-level traits and environmental conditions on the detection likelihood of new records using Bayesian phylogenetic generalized linear mixed models, evaluated how provincial-level survey efforts, species richness and socio-economic factors influenced new record counts using Poisson regression models, and tested whether new records were spatially non-random in direction using chi-square analysis. Results: Chiroptera (n = 69), Eulipotyphla (n = 26), and Rodentia (n = 23) had the highest numbers of new records. Yunnan (n = 31), Guangdong (n = 22), and Xizang (n = 18) yielded the most records. Two new records were discovered in historically unrecognized zoogeographic realms. Smaller-bodied and nocturnal species were more likely to yield new records. New record counts were positively correlated with species richness and current survey efforts (r > 0.5, p < 0.05). New records showed significant directional bias (χ² = 183.8, df = 7, p < 0.01), with 61 (40.7%) extending northward and 32 (21.3%) eastward. Main conclusions: This study expands the known ranges of China’s mammals, mitigate the Wallacean shortfall and sheds light on how species detectability and regional sampling bias shape the accumulation of new records. These findings underscore the urgent need for intensified surveys in biodiversity-rich but underexplored areas and among understudied taxa, especially small-bodied, nocturnal and data-deficient species, to better inform conservation strategies.