Abstract: Water deer (Hydropotes inermis) is an endemic species in East Asia, whose natural distribution onlyoccurs in China and Korean Peninsula. Because of the excessive human disturbance and habitat fragmentation, the population size of water deer has shown a sharp decreasing trend during the last several decades. To better understand their survival conditions in highly isolated urban forest parks, the activity rhythm and habitat preference of water deer in autumn and winter were monitored by infrared camera in Laoshan Forest Park and the surroundings in Nanjing, China. A total of 35 infrared-triggered camera-traps were installed from October 2020 to March 2021. The effects of temperature and vegetation type on the activity rhythm and habitat selection were analyzed using generalized linear model (GLM). During the monitoring period, 233 effective photos of water deer were taken by infrared cameras, contributing to 245 effective detection times. The relative abundance index (RAI) was 10.7. The daily activity rhythm of water deer displayed a typical bimodal pattern, with the intensive daily activities happening from 4:00 to 6:00 and from 18:00 to 20:00. The peak of monthly activities was in December. Temperature had significant effects on the daily activities of water deer, with the activity intensity being the highest when the environmental temperature was within a range from 4 to 6 ℃. Results of the generalized linear model showed that water deer tended to select habitats with evergreen deciduous broad-leaved forest and dominant shrub with height above 120 cm. In addition, the RAI index was positively correlated with the distance to road and negatively correlated with the disturbance index. Compared with its counterparts living in other large-scale nature reserves and water network areas, water deer showed typical morning and evening activity mode, no obvious diurnal or nocturnal activity patterns in Laoshan, with random selection on the distance from the nearest water source. Since the human disturbance in urban forest park is relatively high, reasonable control of human activities in Laoshan Forest Park and surrounding areas could be helpful to better safeguard water deer population in Laoshan.

Key words: disturbance index, microhabitat, temperature, generalized linear model.