Free-ranging livestock grazing shifts the acoustic community in a northeast Asian temperate forest.

Understanding livestock-wildlife interactions, especially in forest ecosystems, is critical for biodiversity conservation and sustainable land management. However, the long-term and cascading impacts of livestock grazing on forest structure and community bioacoustics are important yet largely neglected areas of research. Here, we used acoustic indices and a sound event detection (SED) model to evaluate the effects of continuous cattle grazing on seasonal soundscapes in Northeast China. We collected and analyzed over 18,785 h of recordings from 10 cattle-grazed forest plots and 10 ungrazed forest plots in Northeast China. We identified sound events in each recording via deep learning and calculated six acoustic indices, as well as extracted vegetation characteristics using light detection and ranging point cloud data. Our results revealed that grazing activities significantly changed seasonal soundscape dynamics, with biophony being highest in grazed forests and lowest in ungrazed forests in winter. Livestock shifted the forest soundscape composition by increasing the audibility of birds and insects while decreasing the vocalizations of sika deer (Cervus nippon) and crows, resulting in reduced sound diversity and complexity in grazed forests. We also found that grazing can reduce the leaf area index, herbaceous plants, and canopy density, which can influence these effects indirectly. Interestingly, cowbells noticeably altered the dawn chorus of birds; during spring and summer grazing periods, the chorus was characterized by an increased bird calling rate and greater vocal complexity (elevated Acoustic Complexity Index), patterns consistent with a behavioral adjustment to acoustic masking. This study highlights how livestock modify forest acoustic communities. To preserve natural soundscapes, we suggest mitigating cowbell noise through silent trackers (e.g., GPS) or reduced bell density in priority zones. Sustainable practices, including rotational grazing and buffer zones, are also vital to maintain forest structure and acoustic diversity. We suggest that integrating SED models with acoustic indices provides a robust framework for monitoring such anthropogenic disturbances.