Effects of river restoration on riparian biodiversity in secondary channels of the Pite River, Sweden
2012 (English)In: Environmental Management, ISSN 0364-152X, E-ISSN 1432-1009, Vol. 49, no 1, 130-141 p.Article in journal (Other academic) Published
Between 1850 and 1970, rivers throughout Sweden were channelized to facilitate timber floating. Floatway structures were installed to streamline banks and disconnect flow to secondary channels, resulting in simplified channel morphologies and more homogenous flow regimes. In recent years, local authorities have begun to restore channelized rivers. In this study, we examined the effects of restoration on riparian plant communities at previously disconnected secondary channels of the Pite River. We detected no increase in riparian diversity at restored sites relative to unrestored (i.e., disconnected) sites, but we did observe significant differences in species composition of both vascular plant and bryophyte communities. At disconnected sites, plots closest to the stream featured greater representation of mesic-hydric floodplain species, whereas plots farthest from the stream featured greater representation of mesic-xeric species characteristic of the surrounding upland forest. In contrast, restored sites were most strongly represented by upland species at all distances relative to the stream. These patterns suggest that restoration has resulted in increased water levels in reconnected channels, but that the restored fluvial regime has not influenced the development of characteristic flood-adapted plant communities. This may be due to the short time interval (ca. 5 years) since restoration. Previous studies have demonstrated relatively quick responses to similar restoration in single-channel tributaries, but secondary channels may respond differently due to the more buffered hydrologic regimes typically seen in anabranching systems. These findings illustrate how restoration outcomes can vary according to hydrologic, climatic and ecological factors, reinforcing the need for site-specific restoration strategies.
Place, publisher, year, edition, pages
2012. Vol. 49, no 1, 130-141 p.
biodiversity, boreal, bryophyte, off-channel habitat, restoration, riparian, river, secondary channel, vegetation
IdentifiersURN: urn:nbn:se:umu:diva-37825DOI: 10.1007/s00267-011-9773-6OAI: oai:DiVA.org:umu-37825DiVA: diva2:370241