Homogenization Dynamics and Introduction Routes of Invasive Freshwater Fish in the Iberian Peninsula

Abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Ecological Society of America is collaborating with JSTOR to digitize, preserve and extend access to Ecological Applications. Abstract. Nonnative invasive species are one of the main global threats to biodiversity. The understanding of the traits characterizing successful invaders and invasion-prone ecosystems is increasing, but our predictive ability is still limited. Quantitative information on biotic homogenization and particularly its temporal dynamics is even scarcer. We used freshwater fish distribution data in the Iberian Peninsula in four periods (before human intervention, 1991, 1995, and 2001) to assess the temporal dynamics of biotic homogenization among river basins. The percentage of introduced species among fish faunas has increased in recent times (from 41.8% in 1991 to 52.5% in 2001), leading to a clear increase in the similarity of community composition among basins. The mean Jaccard's index increase (a measure of biotic homogenization) from the pristine situation to the present (17.1%) was similar to that for Californian fish but higher than for other studies. However, biotic homogenization was found to be a temporally dynamic process, with finer temporal grain analyses detecting transient stages of biotic differentiation. Introduced species assemblages were spatially structured along a latitudinal gradient in the Iberian Peninsula, with species related to sport fishing being characteristic of northern basins. Although the comparison of fish distributions in the Iberian Peninsula and France showed significant and generalized biotic homogeniza-tion, nonnative assemblages of northeastern Iberian basins were more similar to those of France than to those of the rest of the Iberian Peninsula, indicating a main introduction route. Species introduced to the Iberian Peninsula tended to be mainly piscivores or widely introduced species that previously had been introduced to France. Our results indicate that the simultaneous analysis of the spatial distribution of introduced assemblages (excluding native species that reflect other biogeographical patterns) and their specific traits can be an effective tool to detect introduction and invasion routes and to predict future invaders from donor regions.

Fish-based groups for ecological assessment in rivers: the importance of environmental drivers on taxonomic and functional traits of fish assemblages

“…Accordingly, similar pattern in species diversity was observed. These results are in accordance with numerous previous studies (Godinho et al, 1997(Godinho et al, , 2000Carmona et al, 1999;Pires et al, 1999Pires et al, , 2004Mesquita and Coelho, 2002;Magalhães et al, 2002aMagalhães et al, , 2002bMagalhães et al, , 2007Clavero et al, 2004;Ferreira and Oliveira, 2004;Clavero and Garcia-Berthou, 2006;Mesquita et al, 2006;Ferreira et al, 2007aFerreira et al, , 2007b. In fact, increasing local species richness along the longitudinal stream gradient is a very well known pattern (e.g.…”

“…Introduction of new species and other human interventions can influence assemblage composition in streams (Vila-Gispert et al, 2002). Homogenization of regional fish faunas by widespread species introductions or extinction of endemic species may blur the roles played by historical factors such as colonization and speciation in shaping local assemblages (Rahel, 2000;Olden and Poff, 2003;Clavero and Garcia-Berthou, 2006;Leprieur et al, 2008;). In the present study, the definition of fish-groups/regions were not influenced by this effect, as collected data showed low occurrence and abundance of non-native species (about 2% of fish density in all captures).…”

Evaluating taxonomic homogenization of freshwater fish assemblages in Chile

“…Human-mediated introductions of species have been a key factor leading to diversity losses in these systems (Clavero and García-Berthou 2006). Fishes are in particular among the most documented introduced species around the world (Rahel 2000) due to aquaculture, recreational fisheries, biological control, and ornamental uses (Ruiz and Marchant 2004;Vargas et al 2010;Marr et al 2010Marr et al , 2013.…”

“…Our expectation was that introduced species with wide distributions might have a larger influence in TH than those with narrow distributions, which conversely are more likely to drive TD. These processes are likely to be driven by similar fish taxa because of convergent human interests around the globe (e.g., salmonids, cyprinids, and poeciliids : Ruesink 2005;Clavero and García-Berthou 2006;Marr et al 2010;Marr et al 2013). To our knowledge, this is the first attempt to broadly evaluate TH in Chile (but see Marr et al 2010), thus permitting assessments of changes in the freshwater fish fauna in order to evaluate current implications for conservation and aid policy-making decisions.…”

The impact of wildfire on stream fishes in an Atlantic-Mediterranean climate: evidence from an 18-year chronosequence

“…The continental territory hosts a diverse assemblage of fish: 51 species are registered from freshwaters, 18 are Iberian endemics, five are unique to Portugal and 15 are introduced (Ribeiro et al, 2007). Although characterized by low taxa richness, upland tributary streams are largely free from invasive species and their associated impact on native fauna (Magalhaes et al, 2002;Clavero and Garcia-Berthou, 2006). Upland streams therefore provide important refugia for native species and represent river habitats of high conservation value (Ribeiro et al, 2000;Filipe et al, 2004;Ribeiro et al, 2009).…”