Modelling the spatio-temporal dispersal of benthic macroinvertebrates in rivers as a tool for predicting recolonization

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An increasing number of river restoration projects targets the improvement of hydromorphological features. Several of these projects, however, have not had the anticipated effects on the biota and failed in terms of recolonization of restored sites by sensitive benthic inver-tebrate species. A widely accepted hypothesis is that dispersal abilities of benthic invertebrate species limit and control recolonization of restored river sections, however, little effort has been spent on the verification of this hypothesis. This project aims at the development and validation of habitat and dispersal models for benthic invertebrate species during their aquatic and terrestrial life stages to better understand and predict their ability to colonize restored river sections. Applying a stepwise approach we will develop grid-based GIS habitat and dispersal models for two catchments and four benthic invertebrate species, representing different dispersal mechanisms and life strategies. The habitat models will predict habitat suitability and spatial distribution of the model species. Models for the dispersal in the aquatic and terrestrial environment will be based on the conversion of environmental variables into “costs” describing the barrier effect on the dispersal of a species. The results of the habitat and dispersal models will be validated by field investigations. Through the comparison of the individual dispersal models we will identify general dispersal pathways for the benthic invertebrate community.