Royal Netherlands Institute for Sea Research

Impacts of biological invasions on species interactions

Invasive species can often have strong impacts on recipient ecosystems. In particular direct effects via predation on and competition with native species have received much interest. Invasive species can also have many indirect effects by mediating species interactions with repercussion for food webs and diseases. However, those have been little studied to date.

This project will investigate the direct and indirect impacts of the recent invasion of two crab species from Asia into the Wadden Sea, Hemigrapsus sanguineus and H. takanoi. The work will involve field studies on the distribution of crabs as well as of their parasites in the Wadden Sea and possibly elsewhere in Europe, laboratory and field experiments on the interaction with the native crab Carcinus maenas and controlled infection studies on the effects on parasites. In addition molecular work on both the crabs as well as their parasites would be possible.


Several independent projects for MSc students will be possible, depending on interests and timing. The length of the student project is approximately 6 months.


For more information and to apply, please contact Prof. Dr David Thieltges ( 

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