Parasites of non-native freshwater fishes introduced into england and wales suggest enemy release and parasite acquisition

When non-native species are introduced into a new range, their parasites can also be introduced, with these potentially spilling-over into native hosts. However, in general, evidence suggests that a high proportion of their native parasites are lost during introduction and infections by some new parasites from the native range might occur, potentially resulting in parasite spill-back to native species. These processes were investigated here using parasite surveys and literature review on seven non-native freshwater fishes introduced into England and Wales. Comparison of the mean numbers of parasite species and genera per population for each fish species England andWaleswith their native ranges revealed\9 % of the native parasite fauna were present in their populations in England and Wales. There was no evidence suggesting these introduced parasites had spilled over into sympatric native fishes. The non-native fishes did acquire parasites following their introduction, providing potential for parasite spill-back to sympatric fishes, and resulted in non-significant differences in overall mean numbers of parasites per populations between the two ranges. Through this acquisition, the non-native fishes also had mean numbers of parasite species and genera per population that were not significantly different to sympatric native fishes. Thus, the non-native fishes in England and Wales showed evidence of enemy release, acquired new parasites following introduction providing potential for spill-back, but showed no evidence of parasite spill-over

The populist radical right in government: The structure and agency of success and failure

Contains fulltext : 111905.pdf (publisher's version ) (Closed access)25 juli 201128 p

How to please voters without alienating friends? Parties, organised interests and advocacy coalitions in Swiss immigration policy

This article seeks to explain why and how political parties adopt more restrictive migration policy positions by using Paul Sabatier’s Advocacy Coalition Framework (ACF). While a number of studies have focused almost exclusively on electoral factors to explain this anti-immigration turn, this article argues that policies and cooperation constraints with organised interests for purposes of coalition maintenance are also fundamental factors to understand change in party positions. Using the Swiss case as an empirical application, the article first shows how an increasingly anti-immigration policy discourse by parties has been triggered by a series of exogenous shocks (economic crisis, European integration and changes in partisan power relationships). Within advocacy coalitions, parties have sought to accommodate changing voter preferences with longstanding connections with organised interests. Centre-right parties have turned to an ever more restrictive stance on selective aspects of immigration policy (third country migration, asylum, access to citizenship) without challenging high levels of EU labour migration so central for employers. Social Democrats, for their part, have had to negotiate between the preferences of their middle–class voters keen on multiculturalism and those of trade unions whose base has become increasingly opposed to migration