Too disturbed or too hot: summer temperatures more than hikers disturbance affect circadian activity of females in northern chamois
Recreational activities often result in a spatial and/or temporal activity shift in wildlife. With the concurrent development of outdoor activities and increase in temperatures due to climate change, mountain species face increasing pressures in terms of managing their activity pattern to limit both risk exposure and thermal discomfort. Using more than 15 years of long-term GPS and activity sensor data, we investigated how female northern chamois, Rupicapra rupicapra rupicapra, adjust their summer circadian activity to spatiotemporal variation in both temperatures and hikers presence. Chamois behaviour was more affected by high temperatures than by hikers presence. During the hottest days, they shifted their activity peak earlier in the morning, were more active at night, less active during daytime and had longer morning and evening peaks compared to the coldest days. Global activity was only slightly different during the hottest than the coldest days. Conversely, hikers disturbance had weak effects on activity levels and on the timing of activity peaks. This is especially true for temporal disturbance (weekdays versus weekends and public holidays), possibly because most weekdays in summer fell during school holidays. During the hottest conditions, the morning activity peak was shorter and the evening peak longer in females living in the most exposed areas compared to females living in the least exposed areas. One possible explanation for the overall low effect of hikers disturbance may be that behavioural changes buffering animals from high temperatures and hikers presence (e.g. moving away from trails) allow them to just marginally modify their activity pattern. In the context of ongoing socioenvironmental changes, it is critical to conserve habitats providing thermal refuges against summer heat and protection from disturbance to mitigate potential detrimental consequences.