Influence of tree cover on the diversity of herbaceous communities in subalpine wooded pastures |
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Authors: | François Gillet Béatrice Murisier Alexandre Buttler Jean-Daniel Gallandat Jean-Michel Gobat |
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Institution: | 1. Laboratoire d'écologie végétale et de phytosociologie, Institut de Botanique, Université de Neuchǎtel, Rue Emile-Argand 11, CH-2007 Neuchǎtel, Switzerland;2. Fax: +41 32 718 21 01 |
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Abstract: | Abstract. The relationships between several diversity indices and tree cover in subalpine wooded pastures with Larix de-cidua were analysed at two spatial scales: phytocoenoses (2500-m2 plots) and herbaceous synusia (1-m2 quadrats). Diversity indices have a non-linear relationship to Larix cover; the best fit was obtained with Gaussian regressions. Species richness was influenced by Larix cover more than evenness. At the phytocoenosis level, the optimum for species and synusial richness in the herb layer was near 25 % tree cover. At the synusia level, species richness of the herb layer showed an optimum when mean distance to the four nearest Larix trees was ca. 30 m, or when the potential number of sunshine hours between April and September was close to 1250 h. Canonical Correspondence Analysis confirmed the influence of Larix cover on the composition of phytocoenoses and herbaceous synusiae, but included also the role of altitude, slope and aspect. |
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Keywords: | Canonical Correspondence Analysis Phytocoenosis Regression Silvopastoral ecosystem Switzerland Synusia |
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