Seasonal niche dynamics and interspecific interactions reveal winter conservation priorities for the endangered Alpine musk deer

The persistence of endangered species in seasonal alpine ecosystems depends on their ability to adjust to fluctuating resources and potential interspecific interactions across multiple niche dimensions. Using camera traps, two-species occupancy models, diel activity analyses, and DNA metabarcoding of diet, we examined how the endangered Alpine musk deer ( Moschus chrysogaster ) responds to seasonal interactions with the dominant sympatric white-lipped deer ( Przewalskium albirostris ). Results showed that, in summer, no clear spatial association was detected (ψBa = 0.545, ψBA = 0.620, SIF = 1.067, 95% CI: 0.826–1.308), while temporal niche differentiation was limited (Δ = 0.87, p = 0.524). Diets differed significantly between species (PERMANOVA, R 2 = 0.236, p < 0.001). In winter, spatial association increased (ψBa = 0.324, ψBA = 0.597; SIF = 1.261, 95% CI: 1.046–1.476). Temporal differentiation also increased (Δ = 0.51, p < 0.001), with musk deer becoming more nocturnal in the presence of white-lipped deer (Δ = 0.66, p = 0.042). Trophic niche use also shifted in winter, with dietary overlap between the two species decreasing from 0.814 to 0.616, while Alpine musk deer showed an increase in dietary niche breadth and dietary evenness. Together, these findings reveal a seasonally shifting, multidimensional niche pattern in Alpine musk deer. This coordinated seasonal variation across niche dimensions is consistent with flexible niche use under resource limitation and potential interspecific competition, further highlighting winter as a critical conservation window for Alpine musk deer and emphasizing the need for multi-season, multidimensional frameworks in endangered species assessment.