Freshwater fish introductions in mediterranean-climate regions: are there commonalities in the conservation problem?
To compare patterns and drivers of freshwater fish introductions across five climatically similar regions and evaluate similarities and differences in the non-native species introduced. Location
Five mediterranean-climate regions: California (USA), central Chile, south-western Australia, the Iberian peninsula (Spain and Portugal) and the south-western Cape (South Africa). Methods
Species presence–absence for native and non-native fishes were collated across the regions, and patterns of faunal change were examined using univariate and multivariate statistical approaches. Taxonomic patterns in freshwater fish introductions were evaluated by comparing the number of species introduced by order to the numbers expected from binomial probabilities. Factors influencing multiple introductions of freshwater fish species in mediterranean regions were determined using generalized linear modelling. Results
High levels of endemism (70–90%) were revealed for south-western Cape, south-western Australia and Chile. Despite their high rates of endemism, all regions currently have more non-native species than endemic species. Taxonomic selection was found for five orders, although this was only significant for Salmoniformes across regions. The average increase in regional compositional similarity of fish faunas resulting from non-native fish introductions was 8.0%. Important factors predicting multiple introductions of a species include previous introduction success and mean latitude of its distribution Main conclusions
The mediterranean-climate regions of the world, separated by vast distances, originally had a few fish species in common but are now more similar, owing to species introductions, illustrating the extent and importance of taxonomic homogenization. Introductions are largely driven by taxonomically biased human interests in recreational fisheries, aquaculture and ornamental pet species.
Document Type: Research Article
Affiliations: 1: Department of Biology, California State University, Chico, CA 95929, USA 2: School of Aquatic and Fishery Sciences, University of Washington, Box 355020, Seattle, WA 98195-5020, USA 3: Institute of Aquatic Ecology, University of Girona, E-17071 Girona, Spain 4: Freshwater Fish Group, Centre for Fish and Fisheries Research, Murdoch University, South Street, Murdoch, WA 6150, Australia 5: Escuela de Graduados, Facultad de Ciencias Forestales, Universidad Austral de Chile, Casilla # 567, Valdivia, Chile 6: Zoology Department, University of Cape Town, Private Bag X3, Rondebosch 7700, South Africa 7: South African Institute for Aquatic Biodiversity, Private Bag 1015, Grahamstown 6140, South Africa
Publication date: 2010-07-01