Long-term taxon-specific responses of macroinvertebrates to dam removal in a mid-sized Swedish stream
2013 (English)In: Rivers Research and Applications: an international journal devoted to river research and management, ISSN 1535-1459, E-ISSN 1535-1467, Vol. 29, no 9, 1082-1089 p.Article in journal (Other academic) Published
Dam removal to restore ecologically impaired rivers is becoming increasingly common. While the target often is to facilitate fish migration, dam removal has also been assumed to benefit other types of organisms. Because few studies thus far deal with effects of dam removal on stream macroinvertebrates, and because results have been equivocal, we investigated both short- and longer-term dam-removal effects on downstream macroinvertebrate communities. We did this in a before-and-after study of the removal of a dam located in a south Swedish stream. We sampled the benthic fauna 6 months prior to dam removal and both 6 months and 3.5 years after the dam was removed. We compared species composition, taxonomic richness, total densities, and densities of macroinvertebrate groups before and after dam removal and between downstream and reference sites. We found that dam removal reduced some macroinvertebrate taxa at the downstream site, but we found no effect on community composition. While this corroborates results from previous short-term studies, we also found a reduction of taxonomic richness and that some dam-removal effects persisted or even increased over time. The most likely explanation for the suppression of benthic macroinvertebrate richness following dam removal is a significantly increased sediment transport from the former reservoir, and a subsequent loss of preferred substrates. Our results indicate that adverse dam-removal effects may be long-lasting, but taxon-specific. We therefore call for longer-term studies on a variety of organisms to better understand how dam removal may influence downstream macroinvertebrate communities.
Place, publisher, year, edition, pages
John Wiley & Sons, 2013. Vol. 29, no 9, 1082-1089 p.
dam removal, river restoration, macroinvertebrate density, taxonomic richness, sediment deposition, long-term effects, Sweden
Biological Sciences Oceanography, Hydrology, Water Resources
Research subject biology
IdentifiersURN: urn:nbn:se:umu:diva-55568DOI: 10.1002/rra.2592ISI: 000325823900002OAI: oai:DiVA.org:umu-55568DiVA: diva2:527470