ESTIMATES OF ALPINE SEED BANK SIZE IN 2 CENTRAL-EUROPEAN AND ONE SCANDINAVIAN SUB-ARCTIC PLANT-COMMUNITIES

Seed bank sizes of two alpine plant communities in the Central Alps wi th differing substrates and of one subarctic alpine site were estimate d on the basis of the emergence of seedlings. Estimates of seed bank s ize to 5 cm depth were 1350 +/- 177 and 1521 +/- 236 seedlings m-2 for the Austrian alpine communities on silicaceous and calcareous substra tes, respectively. Diaspores of 27 to 45% of all the species present i n the communities germinated from a total of 50 soil samples. All seed bank taxa were present in the existing vegetation, as well. The overa ll relative frequency of established taxa in a given community is a we ak predictor for the abundance in the seed bank. Seedling density also is not related to the extent of vegetative cover at the sampling loca tion. Emergence of diaspores from the Swedish subarctic alpine site am ounted to merely 37 +/- 19 seedlings m-2, suggesting that seed bank si ze is low or germination requirements of subarctic/alpine taxa are inh erently different, compared to temperate alpine species.