Forecasting Environmental Responses to Restoration of Rivers Used As Log Floatways: an Interdisciplinary Challenge
Ecosystems (2005) 8: 779–800 DOI: 10.1007/s10021-005-0030-9 Forecasting Environmental Responses to Restoration of Rivers Used as Log Floatways: An Interdisciplinary Challenge Christer Nilsson,1* Fabio Lepori,2 Bjo¨rn Malmqvist,2 Erik To¨rnlund,1 Niclas Hjerdt,1 James M. Helfield,1 Daniel Palm,3 Johan O¨ stergren,3 Roland Jansson,1 Eva Bra¨nna¨s,3 and Hans Lundqvist3 1Landscape Ecology Group, Department of Ecology and Environmental Science, Umea˚ University, SE-901 87 Umea˚ , Sweden; 2Stream Ecology Group, Department of Ecology and Environmental Science, Umea˚ University, SE-901 87 Umea˚ , Sweden; 3Department of Aquaculture, Swedish University of Agricultural Sciences, SE-901 83 Umea˚ , Sweden ABSTRACT Log floating in the 19th to mid 20th centuries has interactions and increasing the retention capacity profoundly changed the environmental conditions of water, sediment, organic matter and nutrients. in many northern river systems of the world. The geomorphic and hydraulic/hydrologic altera- Regulation of flow by dams, straightening and tions are supposed to favor production, diversity, narrowing of channels by various piers and wing migration and reproduction of riparian and aquatic dams, and homogenization of bed structure are organisms. The response rates are likely to vary some of the major impacts. As a result, the condi- according to the types of processes and organisms. tions for many riverine organisms have been al- Some habitat components, such as beds of very tered. Removing physical constructions and large boulders and bedrock outcrops, and avail- returning boulders to the channels can potentially ability of sediment and large woody debris are be- restore conditions for these organisms.
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