Table 1. Names, geographical coordinates, mean altitude, species and number of sampled individuals for the four sampling locations.

Sampling location	Country	Coordinates	Altitude	Species and no. of individuals sampled
Rhône Glacier	Switzerland	46° 34' 03.3'' N 08° 22' 12.3'' E	1770 m	S. purpurea, n=65; S. helvetica, n=66; Hybrids, n=51
Morteratsch Glacier	Switzerland	46° 26' 14.1'' N 09° 56' 01.8'' E	2000 m	S. purpurea, n=39; S. helvetica, n=37; Hybrids, n=6
Inn near San Niclà	Switzerland	46° 51' 28.1'' N 10° 25' 28.4'' E	1070 m	S. purpurea, n=52
Gepatschferner	Austria	46° 52' 45.9'' N 10° 44' 30.7'' E	2065 m	S. helvetica, n=27