Case Study 7 is based in the densely populated Swiss plateau, an area of ca 11.000 km2, and aims to quantify the current state of knowledge on the dominant cause-effect relationships regarding the decrease in ecological status and biodiversity in Swiss plateau rivers. Furthermore, the Case Study uses this knowledge to identify river management strategies that can be expected to have positive effects on the ecological status and biodiversity of rivers on the Swiss plateau while also increasing or not significantly decreasing the provision of so-called ecosystem services. These objectives will be addressed in close collaboration with stakeholders, primarily professionals from governmental agencies in the field of surface water protection, to profit from their knowledge and creativity and to support the design of alternatives that may have the potential of being implemented in Swiss river management plans.
Throughout Europe, rivers have been heavily modified to increase ecosystem services, such as flood protection, agricultural or hydropower production. These modifications include the construction of weirs and dams, channelization and modifications of floodplains for agricultural and urban use. This has led to morphological river degradation, reduction in lateral and longitudinal connectivity, to modified flow regimes and water pollution, but also to a loss of biodiversity and habitats, as well as a decrease of other ecosystem services such as recreational and aesthetic value. So far, efforts to rehabilitate river sections, reduce negative effects of hydropower plants, improve water quality by constructing waste water treatment plants and decreasing pollution from agriculture have shown many positive local effects. These improvements, however, were not yet able to revert the trends of declining biodiversity and habitat loss in Swiss rivers. Case Study 7 considers whether water management could be improved to lead to larger positive effects on biodiversity and habitats, given the same budget and without a considerable loss of ecosystem services.
Research Questions: Specifically, Case Study 7 addresses the following research questions:
1. How to quantify the current state of scientific knowledge about cause-effect relationships between natural and anthropogenic influence factors and the ecological status and biodiversity in rivers on the Swiss plateau?
2. How to support the spatial planning of environmental management of river catchments at the Swiss plateau to improve the ecological status and taking into account the provision of ecosystem services?
Approach: To answer these questions, Case Study 7 constructs a statistical model of macroinvertebrates to investigate different human impacts on biodiversity and ecological status based on the current state of data availability and knowledge. Case Study 7 also addresses these questions by analysing the properties of the stream network on the Swiss plateau at the spatial scale of river catchments and developing spatial criteria that take into account the resilience and connectivity of the ecosystem, e.g. fish migration. Case Study 7 applies these catchment scale criteria to selected catchments at the Swiss plateau to evaluate their current state and to analyse current deficits. In collaboration with practitioners, the Case Study will develop scenarios for different management strategies based on current policies. Case Study partners will then explore potential effects of these management strategies on the ecological state of the catchments and potential implications to other management objectives such as budget constraints and the provision of ecosystem services. During stakeholder meetings, they will present and discuss preliminary results leading to a revision of spatial criteria and management scenarios. Management options considered include morphological river restoration and restoration of impairments by barriers.
Swiss Plateau, Switzerland
Lead partner organisation:
Eawag, the Swiss Federal Institute of Aquatic Science and Technology, leads Case Study 7.