Biological and ecological characteristics of invasive species: a gammarid study

Abstract

Knowledge of characteristics helpful in screening potential invaders and in elaborating strategies to limit their success is highly desirable. We focused on gammarid amphipods from Western Europe and North America to discover biological and/or ecological traits that may explain successful invasion by these species. Two typologies were considered: an analytical one, with groups built on the basis of biological or ecological similarities, and an empirical one, with groups constituted a priori according to a species' invasive status and its fresh or brackish water origin. The results obtained are discussed in the light of three hypotheses that may influence invasiveness: biotic potential, species size and euryoeciousness. The analysis revealed a particular ecological profile for invaders, with a strong influence of salinity tolerance, but no typology was found based on biological characteristics. Invasiveness cannot be predicted from a limited number of criteria, and is the result of a combination of several characteristics. Invasive species therefore exhibit a particular ecological profile rather than a biological one, contrary to most classical explanations.

Abiotic factors affecting habitat selection by two invasive gammarids Dikerogammarus villosus and Pontogammarus robustoides

“…Salinity varies horizontally near river outlets to the sea and where affluents enter larger rivers of different ionic contents (Rozengurt, 1971;Grabowski et al, 2009). Raised ionic content may be beneficial for alien species adapted to brackish water and/or unstable salinity conditions (Devin & Beisel, 2007).…”

Effectiveness of zebra mussels to act as shelters from fish predators differs between native and invasive amphipod prey

“…Both these types of associations with bivalves have been exhibited by various gammarid species: for instance, D. haemobaphes and Gammarus roeselii Gervais, 1835 preferred living mussels (Mörtl and Rothhaupt 2003;Kobak et al 2009), whereas Gammarus fasciatus Say, 1818 and Gammarus fossarum Koch, 1836 selected empty shells as well (Gonzalez and Downing 1999;Kobak and _ Zytkowicz 2007). Ponto-Caspian gammarids invaded Europe in the last century (Ja_ zd_ zewski et al 2002), considerably affecting local environments due to their tolerance to wide ranges of environmental factors, gregariousness and omnivory with a strong tendency for predation (Devin and Beisel 2007;Grabowski et al 2007;Bącela-Spychalska and van der Velde 2013). Thus, their environmental role clearly differs from that played by their native congeners, which undergo displacement by the aliens in areas of co-occurrence (Berezina and Panov 2003;MacNeil et al 2011).…”

Geographic patterns in freshwater gammarid invasions: an analysis at the pan-European scale

“…Identifying potential invaders generally requires paying attention to the role of the biological and 32 ecological features of invaders in order to draw a general profile of species at risk (Williamson 33 and Fitter, 1996; Kolar and Lodge, 2001). This kind of analysis, already performed for 34 gammarids, revealed the predominant role of ecological traits (Devin and Beisel, 2007). An 35 innovative and complementary method is the investigation of geographic patterns in the 36 distribution of invasive and non-invasive species within a taxonomic group.…”