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Titre :
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The seed bank and the between years dynamics of the vegetation of a Mediterranean temporary pool (NW Morocco) (2001)
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Auteurs :
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Laïla Rhazi, Auteur ;
Patrick Grillas, Auteur ;
Laurine Tan Ham, Auteur ;
Driss El Khyari, Auteur
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Type de document :
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Article
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Dans :
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Ecologia Mediterranea (27(1) 2001)
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Article en page(s) :
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69-88
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Résumé :
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The vegetation dynamics were studied for 3 consecutive years on quadrats arranged along permanent transects and the seed bank stocks were counted (1 year) using the germination method in each of the 3 vegetation belts identified (centre: B1, intermediate: B2 and margin: B3). The number of species, the total density of seeds and the percentage of annuals in the seed banks differed significantly between belts, increasing from the centre (B1) toward the margin (B3). The dominant species in the seed banks of the intermediate belt were more similar to those of the centre (B1) than of the margin (B3). The species composition of the vegetation varied with the topographical gradient, the vegetation of the belt B2 being more similar to that of B3 than to that of the centre (B1). Annuals dominated belts B1 and B3 (except in year 3) whereas perennials dominated in B2. The abundance of species in the vegetation was usually poorly correlated with their abundance in the seed banks (total vegetation). There was usually a stronger correlation with the annuals in the outer belts except when perennials dominated the vegetation (B2 and B3 for year 3). The zonation of the vegetation is interpreted as the result of a combination of various spatial constraints. In an intermediate position along the topographical gradients perennials limit the expression of the seed banks of annual species. The comparison of vegetation and seed bank data between years suggests that the location and species composition of the intermediate belt can vary with time. The marginal belt is enriched by species from neighbouring ecosystems in dry years.
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