Ecological Archives E096-073-A1

Helen C. Wheeler, Toke T. Høye, Niels Martin Schmidt, Jens-Christian Svenning, and Mads C. Forchhammer. 2015. Phenological mismatch with abiotic conditions—implications for flowering in Arctic plants. Ecology 96:775–787. http://dx.doi.org/10.1890/14-0338.1

Appendix A. Effect of spring temperature and winter snow depth on timing of snowmelt.

We assessed the effect of mean May temperature and snow depth on the timing of snowmelt using data from a single weather station in Zackenberg Greenland. Multiple regression was used to assess the relative contribution of May temperature and end of winter snow depth on timing of snowmelt. As date of maximum snow depth varied considerably in these years (range DOY 48–139) we used snow depth in the last day of April as our measure of snow depth, with the exception of 2003 where this data was unavailable so we used the snow depth 3 days later. End of winter snow depth was highly correlated with peak winter snow depth (correlation R = 0.98). Correlation between end of winter snow depth and May temperature was very weak (R = -0.13). Both May temperature and end of winter snow depth had significant effects on timing of snowmelt (snow depth: F_1,11 = 40.23, p < 0.0001, temperature: F_1,11 = 5.12, p = 0.044, adjusted R² for model with both variables = 0.77), the association between snow depth and timing of snowmelt was stronger than the association between temperature and timing of snowmelt (Fig. A1).

Fig. A1. Effect of May temperature and snow depth on timing of snowmelt from 1998 to 2011 at Zackenberg, Greenland.

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