Invasive amphipods - Trophic interactions between native and invasive amphipod species in aquatic systems



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(GE 2219/3-1)


Invasion of non-indigenous species has changed dramatically the fauna composition in most freshwater systems. Such alterations are often attributed to strong interaction effects by the invasive speicies, for example predation in case of the establishment of the invasive amphipod Dikerogammarus villosus.

The intension of this project is on the one side to proof the role of the predation effects - especially of D. villosus - on the native fauna under natural conditions, and therefore to receive a better understanding of the impact of invasive amphipods on aquatic macroinvertebrate communities and the food web structures. In doing so, we will determine different amphipod prey organisms by genetic gut content analyses with newly developed 28S and 18S rDNA primers. By combining these genetic analyses with stable isotope analyses, we define the predatory impact of D. villosus, on different prey organisms.

Furthermore, we will investigate how the displacement affects a native species on the population level. Such a displacement might lead  to a reduction in the genetic diversity and create a genetic bottleneck for the remaining fragmented population. We will analyse a long-term dataset and investigate the genetic population structure of the indigenous amphipod Gammarus roeselii in dependence of the invasion of D. villosus. Therefore, populations of G. roeselii, before and after immigration of D. villosus, will be investiged using microsatellite markers.


Financial support

German Research Foundation (DFG)



Since 01/2012



Dr. René Gergs