Temporal niche partitioning between Korean water deer and Siberian roe deer in temperate forests

We conducted a study to clarify the daily activity patterns of Korean water deer (Hydropotes inermis (Swinhoe, 1870)) and Siberian roe deer (Capreolus pygargus (Pallas, 1771)) to assess the potential temporal niche partitioning between these two sympatric species. We hypothesized that the two species would show different diel activity patterns in the temperate forest. Camera traps were employed in Japanese larch plantations (Larix kaempferi (Lamb.) Carrière) and natural deciduous forests on Mt. Gariwang, Pyeongchang, Gangwon Province, South Korea, during the summer of 2023. Kernel density estimation and overlap coefficients were analyzed using video data. The relative abundance index of the Korean water deer was 3.40 in plantations and 14.13 in deciduous forests, while that of the Siberian roe deer was 17.93 in plantations and 35.87 in deciduous forests. The overlap coefficients between the two species were 0.72 in both plantations and deciduous forests, suggesting temporal niche partitioning. Korean water deer exhibited nocturnal activity in plantations but showed no distinct pattern in deciduous forests; however, Siberian roe deer consistently displayed a crepuscular pattern in both habitats. We provide insights into the ecological interactions between these cervid species and highlights the need for further research on seasonal variations in their activity patterns.