In-situ Temperature Stations Elucidate Species’ Phenological Responses to Climate in the Alps, but Meteorological and Snow Reanalysis Facilitates Broad Scale and Long-Term Studies

Linking climate variability and change to the phenological response of species is particularly challenging in context mountainous terrain. In these environments, elevation topography lead a diversity bioclimatic conditions at fine scales affecting distribution phenology. order quantify situ for mountain plants, CREA (Research Center Alpine Ecosystems) installed 82 temperature stations throughout southwestern Alps, different elevations aspects. Dataloggers each station provide local measurements four heights (5 cm below soil surface, 30 above 2 m ground). Given significant amount effort required installation maintenance, we tested whether meteorological data based on S2M reanalysis could be used instead data. Comparison two datasets showed that some indices, including snow melt-out date heat wave index, can vary significantly according origin. More general indices such as daily averages were more consistent across datasets, while threshold-based somewhat lower agreement. Over 12 year period, responses tree (ash ( Fraxinus excelsior ), spruce Picea abies hazel Corylus avellana birch Betula pendula )), coal tits Periparus ater ) common frogs Rana temporaria better explained, from both statistical ecological standpoint, by derived field stations. Reanalysis out-performed data, however, predicting larch Larix decidua budburst date. Overall, our study indicates choice dataset monitoring ultimately depends target variables species, also spatial temporal scale study.