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 investigated the taxonomic, spatiotemporal and biogeographical patterns of new mammal distribution records in China and identified the species-level and provincial-level drivers associated with these records. Location: China. Time period: 2001-2023 Major taxa studied: Mammals Methods: We compiled 192 peer-reviewed papers reporting 225 new occurrence records at the provincial level for 150 mammal species in 26 families across seven orders. We assessed the effects of species-level traits and environmental conditions on the likelihood of new record detections using Bayesian phylogenetic generalized linear mixed models. We also evaluated how provincial-level survey efforts, mammal species richness and socio-economic factors influenced new record counts using generalized liner regression models, and tested whether new records were spatially non-random in directions using chi-square analyses. Results: Three orders, Chiroptera (n = 69), Eulipotyphla (n = 26), and Rodentia (n = 23), had the highest number of new records. Three provinces, Yunnan (n = 31), Guangdong (n = 22), and Xizang (n = 18), reported the most records. Two new records were discovered in historically unrecognized zoogeographic realms. Smaller-bodied, nocturnal and data-deficient species were more likely to have new records. New record counts were positively correlated with species richness and current survey efforts (β > 0.4, p < 0.05). New records showed significant directional bias (χ² = 183.8, df = 7, p < 0.01), with 40.7% of records (n = 61) extending northward and 21.3% (n = 32) eastward. Main conclusions: This study underscores the urgent need for intensified surveys in biodiversity-rich, yet underexplored areas, and among understudied taxa, particularly small-bodied, nocturnal and data-deficient species. By integrating traits, climate, and socioeconomic factors, this study provides a framework to identify where and for which taxa new records are most likely to be detected. This study contributes to mitigating the Wallacean shortfall and informs biogeographical research and conservation strategies.