River restoration and the trophic structure of benthic invertebrate communities across 16 European restoration projects
- 668 Downloads
River restoration enhances not only habitat diversity in the stream channel and riparian zone, but also retention of organic matter, which together are expected to enhance aquatic-terrestrial linkages, and the range of autochthonous and allochthonous resources. Consequently, alterations of food-web structure and trophic relationships can be expected. We applied stable isotope analysis (δ13C, δ15N) to characterize changes in the trophic structure of benthic invertebrate communities between paired restored and unrestored river reaches across 16 European catchments. We sampled dominant taxa of invertebrate assemblages belonging to different functional feeding groups and calculated δ13C range to estimate the diversity of basal resources assimilated, δ15N range as an indicator of the trophic length and standard ellipse area corrected for small samples as a measure of isotopic niche width. We analysed (1) if restoration influences the trophic structure of invertebrates, (2) if effects of restoration depend on the extent of restoration effort, and (3) if effects of restoration depend on restoration measures applied. Our European-scale comparison indicates that river habitat restoration effects trophic structure, primarily by increasing the breadth of resources assimilated by consumers; this effect increases with restoration effort and it depends on restoration measure type.
KeywordsRiver restoration Stable isotopes Trophic structure Food web Freshwater Functional feeding groups Community metrics Isotopic niche
This study results from the EU-funded project REFORM (Restoring rivers FOR effective catchment Management), European Union’s Seventh Programme for research, technological development and demonstration under Grant Agreement No. 282656. We further acknowledge a PhD fellowship of the German Environment Foundation (Deutsche Bundesstiftung Umwelt, DBU) to B.K. We are grateful to many colleagues who spent their time sampling in the field and preparing samples and to the crew of the stable isotope facility for analysing the samples. Two anonymous reviewers provided detailed and constructive comments which have improved this paper.
- Batschelet, E., 1981. Circular Statistics in Biology. Academic Press, London.Google Scholar
- Friberg, N., A. Baattrup-Pedersen, E. A. Kristensen, B. Kronvang, S. E. Larsen, M. L. Pedersen, J. Skriver, H. Thodsen & P. Wiberg-Larsen, 2014. The Gelså River Restoration Revisited: community persistence of the invertebrate community over an 11-year period. Ecological Engineering 66: 150–157.CrossRefGoogle Scholar
- Hering, D., J. Aroviita, A. Baattrup-Pedersen, K. Brabec, T. Buijse, F. Ecke, N. Friberg, M. Gielczewski, K. Januschke, J. Köhler, B. Kupilas, A. Lorenz, S. Muhar, A. Paillex, M. Poppe, T. Schmidt, S. Schmutz, P. J. Vermaat, P. F. M. Verdonschot & R. Verdonschot, 2015. Contrasting the roles of section length and instream habitat enhancement for river restoration success: a field study on 20 European restoration projects. Journal of Applied Ecology 50: 97–106. doi: 10.1111/1365-2664.12531.Google Scholar
- Jähnig, S. C., K. Brabec, A. Buffagni, S. Erba, A. W. Lorenz, T. Ofenböck, P. F. M. Verdonschot & D. Hering, 2010. A comparative analysis of restoration measures and their effects on hydromorphology and benthic invertebrates in 26 central and southern European rivers. Journal of Applied Ecology 47: 671–680.CrossRefGoogle Scholar
- Muhar, S., K. Januschke, J. Kail, M. Poppe, D. Hering & A. D. Buijse, 2015. Evaluating good-practice cases for river restoration across Europe: context, methodological framework, selected results and recommendations. Hydrobiologia (this issue)Google Scholar
- Parnell, A. C., R. Inger, S. Bearhop & A. L. Jackson, 2008. SIAR: Stable isotope analysis in R. http://cran.r-project.org/web/packages/siar.
- R Development Core Team, 2007. R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. http://www.R-project.org.