A comparison of habitat diversity and interannual habitat dynamics in actively and passively restored mountain rivers of Germany
- 461 Downloads
We compared habitat diversity and morphodynamics of ‘actively’ restored reaches (including removal of bank fixation, widening and large wood placement) with ‘passively’ restored reaches (abandonment of channel maintenance) and adjacent non-restored control reaches in medium-sized Central European mountain rivers. Habitat diversity and river morphology were mapped in two consecutive years and changes in habitat composition (channel features, substrates) and morphological changes (active depth and width) were quantified. In both years, habitat diversity was generally higher in the restored reaches compared to their non-restored counterparts, and significantly differed between restoration approaches, with average values in actively restored reaches being about 60% larger than in passively restored reaches. Channel feature composition differed significantly, both between restored and unrestored reaches, and between restoration approaches, whereas substrate composition was similar in all investigated reaches, indicating that restoration had a higher effect on mesohabitat than on microhabitat conditions. Interannual habitat dynamics in respect to channel feature composition were larger in the actively restored compared to the passively restored reaches, while substrate composition remained fairly constant in all reaches. Regarding morphodynamics, changes in depth and width of actively restored reaches differed significantly from changes in passively restored ones in three of the four elements compared. Our findings imply increased habitat richness, diversity and habitat dynamics in the restored reaches, especially in actively restored ones. Analysis of discharge data suggests that flood events exceeding critical shear stress of the bed material, and the time span since restoration determine the potential for morphological changes.
KeywordsActive restoration Passive restoration Habitat diversity Morphodynamics Annual changes Hydromorphology Critical shear stress Floods
This study was funded by the EU Integrated Project Euro-Limpacs (GOCE-CT-2003-505540). The first author received financial support by a PhD Scholarship of the German Business Foundation (Stiftung der Deutschen Wirtschaft) and the research funding programme ‘LOEWE—Landes-Offensive zur Entwicklung Wissenschaftlich-ökonomischer Exzellenz’ of Hesse’s Ministry of Higher Education, Research, and the Arts. We are grateful to several authorities for providing information and data, particularly to Herbert Diehl and Wolfgang Klump from the Hesse State Environmental Agency in Giessen and Wiesbaden for various types of information on the Lahn sites, and the State Environmental Agencies in Cologne, Siegen and Trier for providing discharge data.
- Church M., & K. Rood, 1983. Catalogue of alluvial river channel regime data. Technical Report, Department of Geography, University of British Columbia, Vancouver.Google Scholar
- CLC, 2000. Corine landcover cover. Umweltbundesamt, DLR-DFD 2004.Google Scholar
- Fortin, M.-J., S. Payette & K. Marineau, 1999. Spatial vegetation diversity index along a postfire successional gradient in the northern boreal forest. Ecoscience 6: 204–213.Google Scholar
- Habitat Directive, 1992. Council Directive 92/43/EEC of 21 May 1992 on the conservation of natural habitats and of wild fauna and flora [available on internet at http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:01992L0043-20070101:EN:NOT]. Accessed 28 Dec 2011.
- Hering, D., A. Buffagni, O. Moog, L. Sandin, M. Sommerhäuser, I. Stubauer, C. Feld, R. K. Johnson, P. Pinto, N. Skoulikidis, P. F. M. Verdonschot & S. Zahradkova, 2003. The development of a system to assess the ecological quality of streams based on macroinvertebrates—design of the sampling programme within the AQEM Project. International Review of Hydrobiology 88: 345–361.CrossRefGoogle Scholar
- HMULV (Environmental Ministry of Hesse), 2008. Informationssystem zur Auswahl effizienter Renaturierungsmaßnahmen (Information system to select efficient stream restoration measures) (in German) [available on internet at http://interweb1.hmulv.hessen.de/umwelt/wasser/gewaesser_hochwasser/ISAR_Website/]. Accessed 11 July 2008.
- Hohensinner, S., M. Jungwirth, A. Drescher, G. Egger, G. Haidvogl, S. Muhar, S. Preis & S. Schmutz, 2005. Reconstruction of spatio-temporal habitat dynamics of the Danube river-floodplain system in the Austrian Machland 1812–1991. Geophysical Research Abstracts 7: 08127.Google Scholar
- Kail, J., & C. Wolter, 2011. Analysis and evaluation of large-scale river restoration planning in Germany to better link river research and management. River Research and Applications 27: 985–999.Google Scholar
- Knighton, D., 1998. Fluvial forms and processes: a new perspective. Oxford University Press, Oxford, NY.Google Scholar
- LUA NRW, 2001a. Merkblätter Nr. 29: Referenzgewässer der Fließgewässertypen Nordrhein-Westfalens, Teil 2: Mittelgroße bis große Fließgewässer—Gewässerabschnitte und Referenzstrukturen, Landesumweltamt Nordrhein–Westfalen, Essen: 249 pp.Google Scholar
- LUA NRW, 2001b. Merkblätter Nr. 34: Leitbilder für die mittelgroßen bis großen Fließgewässer in Nordrhein-Westfalen–Flusstypen—Landesumweltamt Nordrhein-Westfalen, Essen: 131 pp.Google Scholar
- Neill C., 1973. Hydraulic and morphologic characteristics of Athabasca River near Forth Assiniboine: the anatomy of a wandering gravel bed river. Technical Report REH/73/8. Alberta Research Council, Highways and River Engineering Division, Edmonton.Google Scholar
- Piégay, H., 2003. Dynamics of wood in large rivers. In Gregory, S. V., K. L. Boyer & A. M. Gurnell (eds), The ecology and management of wood in world rivers—American Fisheries Society Symposium 2000, Vol. 37. American Fisheries Society, Bethesda, MD: 109–133.Google Scholar
- Piégay, H., G. Grant, F. Nakamura & N. Trustrum, 2006. Braided river management: from assessment of river behaviour to improved sustainable development. In Sambrook-Smith, G. H., J. L. Best, C. S. Bristow & G. E. Petts (eds), Braided rivers: process, deposits, ecology and management; special publication 36 of the international association of sedimentologist. Blackwell, Oxford: 257–275.Google Scholar
- Shannon, C. E. & W. Weaver, 1949. The mathematical theory of communication. The University of Illinois Press, Urbana, IL: 187.Google Scholar
- Sommerhäuser, M. & T. Pottgiesser, 2005. Die Fließgewässertypen Deutschlands als Beitrag zur Umsetzung der EG-Wasserrahmenrichtlinie. In Feld, C., S. Rödiger, M. Sommerhäuser & G. Friedrich (eds), Typologie, Bewertung, Management von Oberflächengewässern. E. Scheizerbart’sche Verlagsbuchhandlung, Stuttgart: 13–27.Google Scholar
- Wohl, E., P. L. Angermeier, B. Bledsoe, G. M. Kondolf, L. MacDonnell, D. M. Merritt, M. A. Palmer, N. L. Poff & D. Tarboton, 2005. River restoration. Water Resources Research 41: W10301.Google Scholar