Cepaea on Salisbury Plain: patterns of variation, landscape history and habitat stability |
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Authors: | R A D CAMERON MA CARTER M A PALLES-CLARK |
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Institution: | Department of Extramural Studies, University of Birmingham, P.O. Box 363, Birmingham B15 2TT;Department of Biological Sciences, Portsmouth Polytechnic, Portsmouth, Hants;Leighton Park School, Reading, Berkshire |
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Abstract: | Patterns of variation in Cepaea nemoralis and C. hortensis on Salisbury Plain are related to its landscape history. Areas of arable or mixed farming, with hedgerows and woods, show patterns of variation with habitat and topography. Areas of downland, until recently heavily grazed by sheep, show area effects. Cepaea populations in these downland areas would have been much rarer, and more isolated when grazing was intense. This pattern is repeated in other parts of southern England, showing that area effects in Cepaea are strongly associated with areas of habitat instability, where Cepaea survived as small and isolated populations until recently. This evidence enhances the plausibility of explanations of area effects involving isolation, founder effect or local selection, and co-adaptation. |
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Keywords: | Cepaea populations variation landscape history- habitat |
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