Biodiversität am Piz Alv (2974 m): Lokaler hot spot in der Region Bernina (Graubünden, Schweiz)

Abstract

During the years 2002, 2003 and 2006, vegetation records, 201 in total covering 30 plant communities with a total of 415 vascular plants, were kept about an area of 0.32 km2 at the foot of the Piz Alv (2974 m a.s.l., Bernina pass, Canton of the Grisons, Switzerland). The records have been investigated regarding biodiversity (Shannon-index and evenness) and the constancy of occurrence. In addition an earlier vegetation map of Piz Alv has been revised and completed. On the lower mountain slope the dominating features are acidophilic subalpine meadows (Geo montani-Nardetum), slope peat bogs and pastures, whereas on the upper slope section, basophilic alpine meadows (Seslerio-Caricetum sempervirentis) and pioneer plant communities (Dryadetum octopetalae) prevail. The highest biodiversity is shown by the plant communities Geo montani-Nardetum and Seslerio-Caricetum sempervirentis with 179 and 152 plant species respectively (Shannonindex 2.80 and 2.37 respectively). The highest constancy of plant species occurrence is exhibited by the basophilic alpine meadows (Seslerio-Caricetum sempervirentis), subalpine pastures (Poion alpinae), hanging bogs and alluvions. 10 species of orchids could be recorded and more than 12 additional rare plant species, found in the Swiss Red Data Book, could be recognized. The investigated locality in the Bernina pass area represents a local Swiss hot spot of plant biodiversity and should be put under nature protection