Behavioural thermoregulation by montane ungulates under climate warming

Aim: Global warming is threatening species survival worldwide. Cold-adapted montane ungulates may be among the first species to be affected by global warming. Here, we investigate the behavioural thermoregulation hypothesis that montane ungulates buffer the effects of warming climate through behavioural adjustment. Location: Foping National Nature Reserve (FNNR) on the southern slopes of the Qinling Mountains, Shaanxi, China. Methods: We used infrared camera traps over six consecutive years to monitor behavioural responses of montane ungulates to seasonal and diurnal changes in ambient temperature. We evaluated how seasonal altitudinal migration and changes to their daily activity budget may mitigate the effect of warming on montane ungulates. Results: All four montane ungulate species examined here preferred ambient temperatures <22 degrees C in summer. On this basis, we estimate that 27.9% (+2 degrees C) and 46.7% (+3 degrees C) of suitable summer habitats will become unsuitable under climate change. Chinese muntjac and tufted deer displayed behavioural changes to daily activity budgets, which may help them overcome global climate warming to a certain extent. By contrast, golden takin and wild boar did not display similar behavioural changes, and it may be because they are not affected by current shifts in climate due to larger body size and thus lower thermal stress. Main Conclusions: These analyses demonstrate different species responses to warming are likely and are determined by specific tolerances to ambient temperature thresholds. However, it remains to be seen whether species interactions caused by behavioural shifts may affect species ability to respond to climate.