Abstract:

Aims: Carnivores play a crucial role in maintaining the structural and functional stability of ecosystems. Investigating the mechanisms that allow their sympatric coexistence is critical for understanding community assembly and biodiversity maintenance. This study explores temporal niche differentiation among sympatric carnivores.

Method: From November 2020 to May 2024, we conducted long-term camera-trap monitoring of carnivores in the Shanxi Lishan National Nature Reserve. We analyzed the diel activity patterns of three species—North China leopard (Panthera pardus japonensis), leopard cat (Prionailurus bengalensis), and masked palm civet (Paguma larvata)—using kernel density estimation to compare their circadian activity rhythms. We also assessed how lunar cycles influenced activity intensity.

Results: The North China leopard showed significant seasonal variation in diel activity patterns (P = 0.01), demonstrating partial diurnality in the cold season (Jacobs selectivity index, JSI = 0.28) but a more random temporal distribution of activity in the warm season (r = 0.06, P = 0.78). The leopard cat showed no significant seasonal differences in diel activity levels or patterns (P > 0.05), with high overlap between seasonal daily activity curves (Δ = 0.80, 95% CI: 0.71-0.92). The leopard cat and masked palm civet did not differ significantly in diel activity patterns (P > 0.05; Δ = 0.87, 95% CI: 0.82-0.93); both were primarily nocturnal. However, their activity levels and patterns differed significantly from those of the North China leopard across all seasons (P < 0.05). The civet was recorded only six times during the cold season, indicating seasonal temporal-niche differentiation relative to the leopard cat. In terms of diel activity selection, the civet exhibited a stronger preference for nocturnal activity (JSI > 0.65) than the leopard cat (JSI > 0.55) and showed some avoidance of crepuscular periods (−0.43 < JSI < −0.23). Regarding lunar-cycle effects on activity intensity, no significant differences were observed among the three species across the five lunar phases during the warm season (P > 0.05). In the cold season, however, both the North China leopard and the leopard cat exhibited significant lunar-phase-dependent variation in activity intensity (North China leopard: χ² = 10.84, P = 0.03; leopard cat: χ² = 13.09, P = 0.01). Specifically, the leopard increased nocturnal activity during the full and waning crescent moon phases, whereas the leopard cat exhibited signs of lunar phobia.

Conclusion: These findings provide fundamental insights into the mechanisms of species coexistence among carnivores and offer a scientific basis for biodiversity conservation and ecosystem management in the Lishan region of Shanxi Province.

Key words: carnivores, sympatric distribution, circadian activity rhythms, lunar cycle, Lishan National Nature Reserve