The average global temperature has been reported rising in recent decades, particularly in mountainous regions (IPCC, 2018, 2018). In the European Alps, the average temperature has increased by about 1.1°C over the past 100 years (Böhm et al., 2001). The European Alps were reported to be particularly sensitive to inter-annual variations in climatic drivers such as temperature, precipitation, and solar radiation (Beniston et al., 2003; Gobiet et al., 2014), as well as, depending on elevation, snow cover extent and its depth (Jonas et al., 2008; Xie et al., 2017). Recent climatic warming was reported to have led to considerable variance and shifts in plant phenology across ecosystems (Graven et al., 2013; Parmesan, 2006; Parmesan & Yohe, 2003) and thus may threaten species with synchronized life cycles (Dozier & Painter, 2004; Post et al., 2009). The firm link between phenological changes and seasonal temperature variability suggests that broad-scale and long-term phenology observations could serve as a proxy for detecting and tracing global climate change over space and time (