Abstract

Restoration of channelized streams by returning coarse sediment from stream edges to the wetted channel has become a common practice in Sweden. Yet, restoration activities do not always result in the return of desired biota. This study evaluated a restoration project in the Vindel River in northern Sweden in which practitioners further increased channel complexity of previously restored stream reaches by placing very large boulders (>1m), trees (>8m), and salmonid spawning gravel from adjacent upland areas into the channels. One reach restored with basic methods and another with enhanced methods were selected in each of ten different tributaries to the main channel. Geomorphic and hydraulic complexity was enhanced but the chemical composition of riparian soils and the communities of riparian plants and fish did not exhibit any clear responses to the enhanced restoration measures during the first 5years compared to reaches restored with basic restoration methods. The variation in the collected data was among streams instead of between types of restored reaches. We conclude that restoration is a disturbance in itself, that immigration potential varies across landscapes, and that biotic recovery processes in boreal river systems are slow. We suggest that enhanced restoration has to apply a catchment-scale approach accounting for connectivity and availability of source populations, and that low-intensity monitoring has to be performed over several decades to evaluate restoration outcomes.

Keywords

fish; geomorphic complexity; hydraulics; ice; landscape scale; restoration; riparian chemistry; riparian plants; Sweden

Published in

Ecosystems
2017, Volume: 20, number: 1, pages: 144-162

SLU Authors

• Palm, Daniel

  • Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences
    

• Lundqvist, Hans

  • Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences
    

Sustainable Development Goals

Ensure availability and sustainable management of water and sanitation for all
Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss


UKÄ Subject classification

Ecology
Fish and Aquacultural Science
Oceanography, Hydrology, Water Resources


Publication identifier

DOI: https://doi.org/10.1007/s10021-016-0020-0

Permanent link to this page (URI)

https://res.slu.se/id/publ/77380