Mechanisms and consequences of aquatic invasion in European RiversAquatic Invasion

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founded by the German Research Foundation with an Emmy Noether grant

 

The phenomenon of alien species’ invasion is attracting a growing attention worldwide. Invasion of alien benthic invertebrates is a global and important feature of large rivers and is assumed to pose a threat to biodiversity and ecosystem functioning. While changes of invertebrate communities have been described in detail, it is still unknown whether these structural changes translate into functional changes. The aim of this project is to understand the underlying key mechanisms of invasion and its consequences for ecosystem functioning and water–quality relevant processes. As a model the invasive amphipod Dikerogammarus villosus and its impacts are studied on multiple levels of complexity (individual, population, and community level) with ecological and physiological methods. Field mesocosm experiments will be conducted in three European rivers which differ in their invasion history (dominated by natives, invader-dominated, and invader’s home range). Thereby the effects of different D. villosus densities on biotic interactions and important ecosystem functions are compared among those rivers. This offers the unique opportunity to study invader traits and community features and their importance for the success of a biological invasion over different spatial and temporal scales. In addition it allows estimating the large scale effect of D. villosus invasion.

 

Schema der geplanten Mesokosmosanlage Principle set-up of the mesocosm system we are planning to use in the three rivers. At each site nine channels will be exposed where the sediment filled baskets can be kept at the water surface by a pontoon construction. This system can be disassembled and thus transported relatively easy.

 

Leader Dr. Carola Winkelmann
Researcher Dr. Claudia Hellmann