For effective river management it is important to understand the role of different human impacts and environmental stressors on the structure and function of river ecosystems. In this project we want to explore Swiss monitoring data to identify the cause-effect relationship between anthropogenic stressors, e.g. pollution from agriculture and urban sources, habitat degradation, hydropower, and the community composition of macroinvertebrates and fish. We will take into account environmental variables like height, temperature, hydromorphological conditions, and dispersal limitation that influence the occurrence of organisms. We will analyze different community descriptors as response variables like taxonomic composition at different taxonomic levels, trait composition linking to community function, food web-network-properties to identify most sensitive indicators.
We will use different statistical and mechanistic approaches. The project will consist of three main tasks:
- The Identification of human impacts on macroinvertebrates and fish using different methods from multivariate statistics to identify influence factors on different community descriptors;
- detailed food web analyzes for selected sites to combine structural and functional aspects to find out how food web properties and feeding habits of fish and macroinvertebrates are influenced by environmental conditions and human impacts;
- a further development and application of the mechanistic model streambugs to selected sites to test our understanding of community assembly and improve the predictive capabilities of the model.
The overall goal of this project is to derive guidance for the identification of human impacts on the aquatic communities of Swiss streams.