Succession of riparian plants following dam removal in a boreal stream in central Sweden
(English)Manuscript (preprint) (Other academic)
Worldwide there are numerous aging and non-performing dams that may face removal, for economic or other reasons. Dam removal initiates succession of plant and animal communities as a response to new morphological and hydrological conditions in the channel. We studied the succession of plant communities in riparian reaches upstream and downstream of a recently removed dam in central Sweden over 3 years. We monitored the vegetation development at each site and compared it with a reference site in an unimpacted upstream reach. The two reaches located in the former reservoir developed new riparian zones following dam removal. Plant colonisation in the new riparian zone was fast and species composition became increasingly similar to that of the reference reach. Dam removal largely restored species composition in the riparian zones that were formed in the previous reservoir, indicating that an appropriate species pool was available and that conditions for natural regeneration of riparian vegetation were sufficient. However, a significant decline in species richness in the downstream reach following dam removal may imply that the upstream and downstream effects of removal may differ and that the removal itself may have disturbed the reach downstream of the former dam. Although remaining timber floating structures and four hydroelectric dams upstream may hamper a more complete vegetation recovery we foresee many years of riparian vegetation development before the successional processes slow down.
dam removal, plant colonisation, stream restoration, riparian vegetation, succession, Sweden
Research subject biology
IdentifiersURN: urn:nbn:se:umu:diva-55566OAI: oai:DiVA.org:umu-55566DiVA: diva2:527467
Submitted manuscript2012-05-222012-05-212012-05-22Bibliographically approved