Faculty of Biology
Aquatic Ecology
Universitätsstrasse 5
D-45141 Essen

Room S05T03B45
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PhD thesis: Parasites as indicators for restoration success

Traditionally, communities of free-living species are studied to assess the success of restoration measures. Since all free-living organisms serve as hosts for at least one parasitic species, it can be expected that the diversity of parasites in restored ecosystems will increase. Especially parasite taxa with complex life cycles, such as digenean trematodes, are expected to respond to changes in ecosystem dynamics.

Knowledge of the occurrence and prevalence of host-specific trematodes can provide valuable information on the presence of the required hosts. Thus, trematodes could serve as an integrative indicator for restoration success and local biodiversity, as they depend on the presence of a diverse and intact free-living species community.

To test this, aquatic gastropods are sampled in degraded, restored and near-natural river sections and examined for trematode infections. It can be expected that the increased species diversity and abundance of free-living organisms will be reflected in the parasite fauna, so that we expect a rather low prevalence and species richness in degraded and recently restored sites, whereas sites restored many years ago and near-natural sampling sites can be expected to show a higher prevalence and species richness.

Our results so far indicate a clear correlation between renaturation measures and species richness and diversity of parasite communities.