Seasonal Phenology and Temporal Niche Differentiation of Dung Beetle Communities in Yak Dung from Alpine Meadows of the Eastern Qilian Mountains.

Warm-season alpine meadow pastures on the Qinghai-Tibet Plateau receive large inputs of yak dung, yet the temporal organization of dung beetle communities inhabiting this resource remains poorly understood. From May to October 2025, we investigated dung beetle communities inhabiting yak dung in warm-season alpine meadow pastures of the eastern Qilian Mountains. A total of 28,208 beetles were collected, of which 27,068 individuals representing 12 scarabaeoid taxa were retained for community analyses. The community was dominated by Aphodius, with A. sublimbatus and A. erraticus as the dominant species. Community composition, density, biomass, and diversity showed pronounced monthly variation. Both density and biomass peaked in August, reaching 31.44 adults/pat and 407.38 mg/pat, respectively. Hill-Shannon diversity remained relatively high from July to September, whereas Sørensen beta diversity declined from 0.305 in May to 0.090 in August, indicating greater similarity in community composition among transects in August. Species activity timing and niche breadth also varied markedly among months, while mean Pianka niche overlap increased from 0.567 in May to 0.752 in August and subsequently declined. These results indicate seasonal niche differentiation among dung beetle species in both activity timing and resource use, which may reduce prolonged resource-use overlap and thereby facilitate species coexistence. This study provides a basis for understanding the seasonal dynamics, resource use, and coexistence of dung beetle communities in alpine grazing ecosystems.