Activity-specific evaluation of winter habitat use by Japanese macaques in snow areas, northern Japan: Implications for conifer plantation management

Monocultural conifer plantations are often recognized as low quality habitats for most mammals, owing to the scarcity of understory plants. This paper presents a multifaceted assessment of conifer plantations as habitats of Japanese macaques (Macaca fuscata) inhabiting an area of heavy snow cover in northern Japan. We evaluated habitat use by two macaque troops in cool-temperate forests, including conifer plantations, which are located in the Shirakami Mountains. Habitat use was classified into three behavioral categories; feeding, resting, and traveling. We directly observed two radio-tagged troops by using the scan sampling technique throughout the day during winter, which is the main bottleneck season in terms of food availability. At each sampling event, we recorded the location of different troops and the behavioral patterns of individuals. We then constructed suitability models for each of the three types of habitat use, by using ecological-niche factor analysis (ENFA) with 12 environmental variables. The ENFA results showed that macaques avoid old conifer plantations, but use young conifer plantations for all behavioral categories, especially as feeding sites. However, the suitability models indicated that geographic features have a larger influence on macaque habitat use than forest cover type. In fact, the feeding, resting, and traveling sites were concentrated on the southern slopes of near the roads at low altitudes. Our findings provided a reasonable indication that macaque habitat use during the snowy season has greater sensitivity to microclimate, such as the amount of sunlight and air temperature, compared to other environmental conditions (e.g., the distribution of food resources). In light of this finding, we suggest that standard timber production does not necessarily directly compete with the conservation of macaque habitats.