Reservoirs promote the taxonomic homogenization of fish communities within river basins

• DOI: 10.1007/s10531-010-9945-3
• Publication Date: 2010-11-16T04:53:30Z
• Authors: Miguel Clavero; Virgilio Hermoso
• Keywords: 0106 biological sciences; 570; Environmental management; Biotic homogenization b-diversity; beta-diversity; Evolution; 590; 01 natural sciences; Ecological applications; 1105 Ecology; 2309 Nature and Landscape Conservation; Behavior and Systematics; 14. Life underwater; Ecology; Freshwater fish; Invasive species; Mediterranean rivers; 15. Life on land; Biotic homogenization; Fish conservation; 6. Clean water; Regulated rivers; Freshwater ecology; 2303 Ecology

Peer reviewed<br/>Most studies analyzing patterns in biotic homogenization of fish communities have used large-scale approaches, while the community-level effects of species intro- ductions and local extinctions within river basins have been sparsely analyzed. In this article, we examine patterns in freshwater fish a- and b-diversity in relation to the presence of reservoirs in a Mediterranean river (Guadiana river; Iberian Peninsula). We used fish samples from 182 river localities and 59 reservoir ones to address two main questions: (i) do reservoirs favor the establishment of invasive fish species?; and (ii) do reservoirs bear taxonomically homogenized fish communities? Although total species richness was not different between rivers and reservoirs, the latter had more invasive species and less native ones. Fish species found in reservoirs tended to be larger ones, but invasive species of any size showed higher preferences for reservoirs. Native species that were rare or absent in reservoirs were those that showed higher sensitivity to invasive species in rivers. Reservoir fish communities were taxonomically homogenized in relation to river ones, both when considering all fish species and using only natives or only invasive ones. Our results suggest that invasive species occupying reservoirs constitute an ecological filter excluding most native species from such systems. Invasive species in the study area are often widely introduced elsewhere, while native species found in reservoirs are congeneric and eco- logically similar to those found in other Iberian studies. Thus, we conclude that reservoirs<br/>