ALBERT

Description: Timing and accumulation of snow are among the most important phenomena influencing land surface phenology in mountainous ecosystems. However, our knowledge on their influence on alpine land surface phenology is still limited, and much remains unclear as to which snow metrics are most relevant for studying this interaction. In this study, we analyzed 5 snow and phenology metrics, namely timing (snow cover duration, SCD); last snow day, LSD), accumulation of snow (mean snow water equivalent, SWE m ), and mountain land surface phenology (start of season, SOS; length of season, LOS) in the Swiss Alps during the period 2003–2014. We examined elevational and regional variations in the relationships between snow and alpine land surface phenology metrics using multiple linear regression and relative weight analyses, and subsequently identified the snow metrics that showed strongest associations with variations in alpine land surface phenology of natural vegetation (NV) types. We found that the relationships between snow and phenology metrics were pronounced in high elevational regions and alpine natural grassland and sparsely vegetated areas. SOS was influenced primarily by SCD, secondarily by SWE m , while LOS was equally affected by SCD and SWE m across different elevational bands. We conclude that SCD plays the most significant role compared to other snow metrics. Future variations of snow cover and accumulation are likely to influence alpine ecosystems, for instance their species composition due to changes in the potential growing season. Also, their spatial distribution may change as a response to the new environmental conditions if these prove persistent.