How Do Biota Respond to Additional Physical Restoration of Restored Streams?
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- 作者：Christer Nilsson ; Judith M. Sarneel ; Daniel Palm ; Johanna Gardeström…
- 关键词：fish ; geomorphic complexity ; hydraulics ; ice ; landscape scale ; restoration ; riparian chemistry ; riparian plants ; Sweden
- 刊名：Ecosystems
- 出版年：2017
- 出版时间：January 2017
- 年：2017
- 卷：20
- 期：1
- 页码：144-162
- 全文大小：1325KB
- 刊物类别：Biomedical and Life Sciences
- 刊物主题：Ecology; Plant Sciences; Zoology; Environmental Management; Geoecology/Natural Processes; Hydrology/Water Resources;
- 出版者：Springer US
- ISSN：1435-0629
- 卷排序：20
文摘
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 (>1 m), trees (>8 m), 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 5 years 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.