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Subalpine-nival gradient of species richness for vascular plants, bryophytes and lichens in the Swiss Inner Alps = Gradient subalpin-nival de la richesse spécifique des plantes vasculaires, bryophytes et lichens dans les Alpes internes en Suisse

Vittoz, Pascal ; Camenisch, Martin ; Mayor, Romain ; Miserere, Luca ; Vust, Mathias ; Theurillat, Jean-Paul

In: Botanica Helvetica, 2010, vol. 120, no. 2, p. 139-149

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    Titre
    • Subalpine-nival gradient of species richness for vascular plants, bryophytes and lichens in the Swiss Inner Alps
    Titre traduit ()
    • Gradient subalpin-nival de la richesse spécifique des plantes vasculaires, bryophytes et lichens dans les Alpes internes en Suisse
    Auteur
    • Vittoz, Pascal. Department of Ecology and Evolution, Faculty of Biology and Medicine, University of Lausanne, Bâtiment Biophore, 1015, Lausanne, Switzerland
    • Camenisch, Martin. Camenisch & Zahner, Weinbergstrasse 6, 7000, Chur, Switzerland
    • Mayor, Romain. Institute of Plant Sciences, Bern University, 21 Altenbergrain, 3013, Bern, Switzerland
    • Miserere, Luca. Via Melchiorre Voli 14, 10135, Turin, Italy
    • Vust, Mathias. Rue Montolieu 5, 1030, Bussigny, Switzerland
    • Theurillat, Jean-Paul. Fondation J.-M. Aubert, 1938, Champex-Lac, Switzerland
    Type de document
    • Postprint
    Langue
    • Inglese
    Publié dans
    • Botanica Helvetica, 2010, vol. 120, no. 2, p. 139-149. SP Birkhäuser Verlag Basel
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:315186
    Summary
    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 1×1-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