Ambient temperature
Transition of air temperature in the study site indicated relatively stable thermal conditions during the survey period (term 1–5) in both years (Fig. 1). Daily mean temperatures during the flowering season ranged between 10–15 ºC, daily minimum temperatures were 6–10 ºC, while daily maximum temperatures fluctuated between 10 and 23 ºC. Thus, the seasonal gradient of thermal conditions was less clear during the flowering periods. During the winter time, from early December to mid-March, daily minimum temperatures were often below zero, but daily maximum temperatures mostly remained above zero.