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Descripción
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| The high heterogeneity of the Mediterranean riparian areas along with their multiple sources of degradation, make responses of vegetation to flow alteration difficult to predict. In addition, most studies on impacts of flow changes in Mediterranean corridors have specifically addressed certain species, with no easily transferable results to similar stream types in other geographic regions. Given that species tend to associate according to similarity in response to environmental conditions (i.e., hydrologic regime for riparian zones), in this study we classified the riparian species of a Spanish stream into guilds using clustering techniques and ordination analysis and examined the responses of riparian guilds to flow regulation. We compared the changes in guild abundance that occurred following the construction of a dam in 1956 which caused a significant decrease of stream discharge. For comparisons, we used pre-dam and post-dam established vegetation bands identified based on old and modern air photographs and on field measurements of woody species diameter. Responses to flow regulation varied between vegetation guilds according to the ecological requirements of their dominant species. The ability to survive water stress (i.e., Xeric guilds) and to hydrogeomorphic disturbances (i.e., Torrential guilds) resulted in a shift of certain pioneer shrub-dominated guilds (e.g., Flueggea tinctoria and Salix salviifolia dominated guilds). In contrast, new hydro-morphological conditions following damming limited the recruitment of native late-successional tree guilds which were sensitive to floods (i.e., to drag forces and to inundation and anoxia; Slow-water and Flood-sensitive guilds, respectively) and of those with greater water requirements (i.e., Hydric guilds) (e.g., Alnus glutionosa and Celtis australis dominated guilds). The guild approach provides information about the general trends in plant populations and assemblage structures and allows generalizations and comparisons among different fluvial systems. | |
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Internacional
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Si |
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Entidad
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9th ISE 2012, BOKU, Vienna |
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Lugar
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Viena |
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Páginas
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1-8 |
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Referencia/URL
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www.ise2012.boku.ac.at/ |
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Tipo de publicación
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Acta de Congreso Internacional con revisores |