Spatiotemporal Patterns of Five Sympatric Ungulates in the Tangjiahe National Nature Reserve, Sichuan, China

Ungulates serve as a critical link between primary producers and higher-level consumers, and play an irreplaceable role in maintaining the structural and functional integrity of forest ecosystems. Understanding the spatiotemporal niche differentiation of sympatric ungulates is of great guiding significance for forest biodiversity conservation and refined habitat management. Based on camera-trapping data collected across the entire Tangjiahe National Nature Reserve from 2022 to 2024, this study systematically analyzed the relative detection intensity, multi-scale activity rhythms, spatiotemporal niche overlap characteristics, and environmental response patterns of five sympatric ungulate species: the Chinese takin (Budorcas tibetana), Chinese serow (Capricornis milneedwardsii), Chinese goral (Naemorhedus griseus), tufted deer (Elaphodus cephalophus), and forest musk deer (Moschus berezovskii). The results showed that the relative detection intensity of the five ungulates exhibited a three-tiered hierarchical pattern, with the Chinese takin showing the highest relative detection intensity and the Chinese serow and forest musk deer showing the lowest detection rates. Fitted diel activity curves were characterized mainly by crepuscular bimodal patterns, whereas forest musk deer showed a predominantly nocturnal unimodal pattern; the DI of Chinese serow showed no statistically supported overall bias between the predefined daytime and nighttime windows. Seasonal overlap coefficients and activity curves indicated species-specific seasonal adjustment, with Chinese serow showing the greatest cold–warm-season divergence and Chinese goral the highest seasonal similarity. The three widely distributed species displayed moderate to high spatiotemporal overlap, whereas the two narrowly distributed species showed pronounced differentiation in spatial-use patterns. Generalized additive models further revealed species-specific nonlinear associations with environmental variables, with elevation and distance to roads emerging as the most consistent predictors across all five species. These findings characterize the spatiotemporal niche differentiation pattern of sympatric ungulates in the Minshan Mountains, and offer a scientific basis for targeted monitoring and conservation of species with low detection rates, habitat zoning optimization, and seasonally adaptive regulation of human disturbance within the nature reserve.