Determining the Distribution of Red Deer (Cervus elaphus L.) in the Kopački Rit Nature Park Using Bioacoustic Monitoring

Red deer (Cervus elaphus), as a highly vocal species, provide versatile ecosystem functions beyond grazing. Their flexible use of different habitats allows them to occupy a variety of ecosystems. As global efforts to conserve biodiversity increase, there is a growing need for new approaches to continuous wildlife monitoring. Bioacoustics is a rapidly developing field that provides valuable data, especially in environments that are difficult to access. The spatial occupancy of red deer in Kopački Rit Nature Park was investigated using passive acoustic devices during the rutting season (September–October) in 2023 and 2024. A total of 332,302 recordings were collected with AudioMoth devices configured to record for 1 min every 5 min over a 10-day period. A recognition model was trained on the Arbimon platform, and a random forest model was applied to the detection data. The occupancy model revealed differences in spatial occupancy between the two years. Although none of the tested covariates showed statistically significant effects, the observed differences likely reflect unmeasured ecological dynamics, such as hydrological variability and resource availability. These findings highlight the potential of passive acoustic monitoring as a reliable, non-invasive approach for large mammal studies.