Daily activity rhythm of roe deer in Wulingshan Nature Reserve, Miyun District, Beijing

Rhythms are key indicators of wild animals' adaptive strategies to varying environmental conditions. Ungulates play a crucial role in forest ecosystems, influencing not only the structure of plant communities but also the dynamics of predator-prey interactions, particularly in relation to large carnivores. However, there is a lack of comprehensive studies on the long-term and seasonal variations in the activity rhythms of hoofed species. This study focuses on the roe deer (Capreolus pygargus) in the Wulingshan Nature Reserve, Miyun District, Beijing, as a model species. Using infrared camera trap data collected from 2016 to 2021, we applied non-parametric kernel density estimation to analyze the temporal patterns of roe deer activity. This approach allowed us to explore the seasonal and long-term variations in their daily activity rhythms, providing insights into how these animals adapt to changing environmental conditions. The results indicated that the activity rhythms of roe deer in the Wulingshan Nature Reserve remain stable over extended periods, with the annual activity patterns showing low sensitivity to minor environmental changes. The daily activity rhythm of roe deer has obvious characteristics of morning and evening activity, with peak intensities observed at 05: 00 - 10: 00 and 17: 00 - 20: 00, respectively. Roe deer are more active at night in spring and summer. The activity overlap coefficient of roe deer in each season was above 0.83, and there was no obvious seasonal difference in activity rhythm. The highest overlap coefficients were observed between spring and summer (Δ4 = 0.900 8), and the lowest between spring and winter (Δ4 = 0.834 7). During summer time, roe deer tended to forage earlier and later in the day. Whereas in winter, they exhibited a delayed morning activity peak, an earlier evening peak, and a longer duration of peak activity compared to other seasons. This study found that the daily activity rhythms of roe deer in the Wulingshan Reserve exhibits no significant seasonal variation, with primary activity occurring in the morning and evening and nocturnal activity being less pronounced. The findings of this study offer a solid scientific foundation for evaluating the success of roe deer habitat restoration and the stability of the associated food chain. Additionally, they provide critical insights that can inform strategies for the reintroduction and management of large carnivores in conservation efforts.