Patterns of Avian Frugivory in Beijing's Urban Forest Across Multiple Temporal Scales

Avian frugivory is a vital process shaping the diversity of bird and plant species. Nevertheless, how this process varies temporally in urban forests is not well understood. In this study, we employed arboreal camera trapping to investigate the temporal patterns of bird-fruiting tree interactions across hourly to annual time scales in three urban forest sites in Beijing, China. We captured 618 independent frugivory events involving 19 bird species and 12 fruiting tree species from 584,886 images recorded in 12 months. Large-scale temporal events like fruiting phenology and bird migration had primary effects on the seasonal patterns of frugivory events, while site conditions, including fruit tree diversity and human activities, significantly affected the monthly and diurnal patterns. The structure of the interaction network also reflected the effects of these factors. Our results show that maintaining consistent fruit availability and minimizing human disturbances are critical for sustaining avian frugivory in urban forests. Additionally, the results show that observations at high temporal resolutions are indispensable for understanding avian frugivory in urban environments.