Deliverable D5.D – Exotic species in multi-stressor context Funded by the European Union within the 7th Framework Programme, Grant Agreement 603378. Duration: February 1st, 2014 – January 31th, 2018 Deliverable D5.D: Report on the position of exotic species in the context of estuaries, rivers and lakes multi-stressors and regarding ecosystem services Lead contractor: Irstea Contributors: Maxime Logez, Benjamin Agaciak, Christine Argillier, Mario Lepage, Nils Teichert (Irstea), Rafaela Schinegger, Stefan Schmutz (BOKU), Pedro Segurado, Maria Teresa Ferreira (ULisboa), Guillem Chust, Ainhize Uriarte, Angel Borja (AZTI) Due date of deliverable: Month 33 Actual submission date: Month 37 Dissemination Level PU Public X PP Restricted to other programme participants (including the Commission Services) RE Restricted to a group specified by the consortium (including the Commission Services) CO Confidential, only for members of the consortium (including the Commission Services) Page 1/51 Deliverable D5.D – Exotic species in multi-stressor context Content Non-technical summary ............................................................................................................. 3 Introduction ................................................................................................................................ 5 Methods ...................................................................................................................................... 7 Available data ......................................................................................................................... 7 Sites description ..................................................................................................................... 8 Fish species status .................................................................................................................. 9 Fish functional traits ............................................................................................................... 9 Functional diversity .............................................................................................................. 10 Results ...................................................................................................................................... 11 Regional species pool ........................................................................................................... 11 Distribution of native, translocated and exotic species ........................................................ 14 Functional attributes of fish species ..................................................................................... 19 Distribution of species with fishing interest ......................................................................... 24 Impact of non-native species on species of fishing interest ................................................. 31 Discussion ................................................................................................................................ 32 References ................................................................................................................................ 40 Supporting Materials ................................................................................................................ 46 Page 2/51 Deliverable D5.D – Exotic species in multi-stressor context Non-technical summary Non-native species, i.e. species occurring outside of their native range, have been recognised as a major threat for ecosystem functioning. Indeed, the number of non-native species introduced at all continents to support human activities or needs has increased during the last decades and several non-native species are now spread worldwide, e.g. mosquitofish species or salmonids. Aquatic ecosystems are particularly sensitive to these introductions. Numerous evidences were provided concerning their impact on native biota, at different levels of organisation (genetic, individual, population, community and ecosystem). Invasion biology is a complex discipline as the success of establishment of non-native species in new locations is driven by numerous factors that depend on the local context. Local environmental conditions, species tolerance, native biota and life history traits were hypothesised as key factors controlling the invasion success of an introduced species. The main objective of this study was to assess the impacts of non-native species on fish assemblages all along the freshwater-marine continuum at large scale in Europe. We thus considered lakes, rivers and estuaries of France, Spain and Portugal. The status of each species was defined at the national level (native, translocated or exotic) and served to assess the relative abundance of non-native species in fish assemblages. In order to understand the ability of non-native species to colonise new areas, we compared their characteristics to those of the native species through two components of functional diversity: specificity and originality. Results showed that estuaries were very different from lakes and rivers, with less non-native species. All were freshwater species with low occurrence and low abundances (Lepomis gibbosus, Ameiurus melas, Sander lucioperca. Silurus glanis, Carassius carassius, Cyprinus carpio). In contrast, in lakes and rivers, non-native fish species occurred in about 25% of fish assemblages, although with heterogeneous distributions across systems. Lakes were approximately four times more affected by the occurrences of non-native species than rivers. In France, Portugal and Spain, almost 1/3 of the regional species pools were composed of non-native fish species, with the pikeperch (Sander lucioperca), the pumpkinseed (Lepomis gibbosus), the largemouth bass (Micropterus salmoides) and the European catfish (Silurus glanis) being the most common non-native species encountered. With the exception of some particular locations, when non-native species were present, they only accounted for a small proportion of local fish abundances (on average 16.78% of catches). We also observed that the non-native species pool was overall more functionally original and specialized than the native species pool. This pattern suggests that non-native fish species exhibit functional traits that tend to differ from those of native species, which is consistent with previous observations. Moreover, this highlights the role played by non-native species in the functional richness of some assemblages, especially on the Iberian Peninsula, where local species and functional richness were generally low. A majority of non-native fish species investigated is known to be of interest, either for commercial or recreational fishing and, consequently, they have a high economic value. This Page 3/51 Deliverable D5.D – Exotic species in multi-stressor context observation is especially true on the Iberian Peninsula, where approximately half of the fished species represent non-native species. However, some of these non-native species with fishing interest are also known to deteriorate water quality, i.e. to increase nutrients and thus contributing to eutrophication of reservoirs. The management of non-native species (removal, control, etc.) should be integrated within an ecosystem service assessment framework, to weight the cost/benefits of given actions. Page 4/51 Deliverable D5.D – Exotic species in multi-stressor context Introduction The increasing concern about biodiversity conservation in face of a generalization of anthropogenic activities and their impacts gave rise to a huge literature focusing on the risk associated to introduced and invasive species in new environments (Lodge 1993). Indeed, it was claimed that introductions of non-native species may impair composition and structure of the communities, modify the whole ecosystem functioning and lead to an homogenization of communities (Vitousek 1990, Williamson 1996, Olden and Poff 2004, Villéger et al. 2014, Villéger et al. 2015). From an evolutional point of view, the geomorphological structure of freshwater ecosystems has been viewed as isolated biogeographic islands (Hugueny 1989), as natural barriers (ocean and land) limit connections between watersheds, with the exception for species tolerant to brackish waters (e.g. long distance migratory fish). These barriers to migration could have been overcome in some rare situations such as ice melting at the end of the last-glacial maximum (Hewitt 2000). The spread of non-native species after their introduction could potentially be limited in aquatic systems, as these natural barriers would prevent fish migration between basins. In spite of this limitation, non-native fish species are also now found in a large number of waterbodies (Welcomme 1988, Cowx 1998, Irz et al. 2004). It has been hypothesized that both artificial connections (i.e. channels) between waterbodies (Rahel 2007, Leuven et al. 2009) and fish stocking play a major role of in the spread of non-native fish into new habitats (Goudswaard et al. 2008, Gozlan et al. 2010b). Fish introduction could be accidental, when undesirable individuals are introduced with another native fish itself introduced to support natural population. It could also be intentional, as non-native fish are stocked to enhance recreational or professional fishing activities (Welcomme et al. 1983, Welcomme 1988, Holčík 1991, Cowx 1994, Crivelli 1995, Cowx 1998). Even if most introduced species do not succeed in settling (Williamson and Fitter 1996, Marchetti et al. 2004,