Assessment of freshwater ecosystem services : with a case study in river Arbogaån

Sammanfattning: Humans are dependent on a large variety of services that come from the eco-systems around us. Some of these ecosystem services are provided by rivers and lakes and include for example drinking water, water for irrigation and industry, flood control, climate regulation, and recreation. Ecosystem ser-vices are increasingly threatened by human activities, including hydropower, forestry, agriculture and fisheries. Another threat is climate change which will lead to for example intensified rainfall, more frequent flooding, and higher temperatures. This study aims to contribute to the understanding of what in-dicators and methods that can be used for assessing freshwater ecosystem services, and to evaluate and describe how flooding might affect the condition of them. This was done by conducting both a literature review of previous research and a case study of the river Arbogaån. During the literature review 344 indicators were found that could be used for assessment of freshwater ecosystem services status. Different methods for assessing ecosystem ser-vices were also examined, for example expert judgements, case studies, qual-itative vs quantitative methods, and citizen science. The review also gave an understanding of how climate change could affect freshwater ecosystem ser-vices, and the results showed that primarily drinking water and biological di-versity are threatened in Europe. In the case study of river Arbogaån, a new method was developed for assessing flooding impacts on ecosystems ser-vices. The method consisted of a GIS overlay analysis and an assessment of flooding impacts based on previous research. The method can be used as a starting point for future research, when assessing the impacts of climate change on ecosystem services. The method was tested on six ecosystem ser-vices that are assumed to be sensitive to climate change (flooding) in river Arbogaån. The assessment indicated that biological diversity, drinking water, and habitat will be affected negatively by flooding in river Arbogaån. No change in condition was found for flood control or water for irrigation and industry, and not enough data was available to estimate the effects on regula-tion of eutrophication. Without knowledge on how climate change influence ecosystem services and how to assess it, it will be impossible to know when, where and what actions that are necessary to protect them. The findings pre-sented in this master thesis provide a framework for future studies wanting to explore similar issues.