Between Scylla and Charybdis – managing connectivity for freshwater fish
Anthropogenic fragmentation has particularly strong effects in dendritic networks, like river-scapes, where there is only one connecting route between two locations. Man-made obstacles, such as dams and weirs, often form absolute barriers for upstream migration, with many negative effects on fish communities. Restoring connectivity by removing barriers is thus important for improving the functioning of stream-lake networks, but may have unwanted side-effects by facilitating the spread of invasive species.
The overarching objective is therefore to provide a decision support system for the management of connectivity in the form of interactive maps of river-scapes. The maps will be provided as a web service and show local slopes, colonization probabilities, and extinction risks for different management scenarios proposed by the user. The decision support system will be developed for Scandinavia, where much of the required infrastructure in the form of high-resolution geographic and ecological data is available. An important sub-objective is to provide a road map for the development of similar systems for other EU-regions.
The requirements in the form of data and models that underlie the decision support system are extensive. Important project activities are thus the development of ecological and geographical databases and models as well as their integration and implementation in a web service:
• Quantification of the ability of important native and non-native species to pass barriers and colonize.
• Quantification of relationships between fragment size and extinction rates for these species.
• Studies of how the effects of connectivity interact with other anthropogenic stressors such as drought, water quality, climate change and invasive species.
• Development and implementation of a web service that allows managers to investigate the ecological consequences of connectivity modifications.
Coordinateur du projet :
Umeå University, Umeå, SWEDEN (Coordinator)
Institut de Recherche pour le Développement
Norwegian University of Technology and Science, Trondheim, NORWAY
Norwegian Institute for Nature Research, Trondheim, NORWAY
University of Girona, Girona, SPAIN
Luleå University of Technology, Luleå, SWEDEN
Contact BOREA : Céline Bellard