Subalpine-nival gradient of species richness for vascular plants, lichens and bryophytes in the Swiss Inner Alps

Détails

ID Serval
serval:BIB_90921FCA48F4
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Subalpine-nival gradient of species richness for vascular plants, lichens and bryophytes in the Swiss Inner Alps
Périodique
Botanica Helvetica
Auteur(s)
Vittoz P., Camenisch M., Mayor R., Miserere L., Vust M., Theurillat J.-P.
ISSN
1420-9063
Statut éditorial
Publié
Date de publication
2010
Peer-reviewed
Oui
Volume
120
Numéro
2
Pages
139-149
Langue
anglais
Résumé
In the European GLORIA project, 12 summits (treeline to nival belt) were inventoried in three regions of Switzerland: two in the Swiss National Park Graubünden and one in Valais. Vascular plants were recorded in all three regions and bryophytes and lichens were recorded only in Valais. On each summit, vegetation and temperature data were sampled using sampling protocols for the GLORIA project (Global Observation Research Initiative in Alpine environment) on large summit sections and in clusters of four 1x1-m quadrats. We observed a general decrease of species richness for all three systematic groups with increasing elevation in the summit sections, but only for vascular plants in the quadrats. In Valais, there was higher species richness for vascular plants than for bryophytes and lichens on the lower summits, but as the decrease in species richness was less pronounced for cryptogams, the latter were more numerous than vascular plants on the highest summit. Vascular species showed a clear shift of the dominant life form with elevation, with chamaephytes replacing hemicryptophytes. Bryophytes and lichens showed a weak trend among the life forms at the summit section scale, but a stronger shift of the dominant forms was seen in the quadrats, with cushion replacing turf bryophytes and crustaceous replacing fruticose lichens. Altogether, these results sustain the temperature-physiographic hypothesis to explain the species richness decrease along the altitudinal gradient: the harsh climatic conditions of the alpine-nival belts act as a filter for species, but the diminishing diversity of microhabitats is also an important factor. Because cryptogams depend more on humidity than temperature and more on smaller microhabitats than vascular plants, the decrease of species richness is more gradual with elevation for bryophytes and lichens.
Mots-clé
Altitude, Aspect, Diversity, Elevation range, Life forms, Switzerland
Web of science
Création de la notice
22/09/2010 12:32
Dernière modification de la notice
03/03/2018 19:25
Données d'usage