首页 | 官方网站   微博 | 高级检索  
     


Responses of fishes and lampreys to the re‐creation of meanders in a small English chalk stream
Authors:G H Copp  C D Sayer  H M Clilverd  L George  L Vilizzi  J Clarke  A M Walker
Affiliation:1. Salmon and Freshwater Team, Centre for Environment, Fisheries and Aquaculture Science, Lowestoft, Suffolk, UK;2. Centre for Conservation Ecology and Environmental Science, Bournemouth University, Poole, Dorset, UK;3. Environmental Change Research Centre, Department of Geography, University College London, London, UK;4. Department of Ecology and Vertebrate Zoology, Faculty of Biology and Environmental Protection, Uniwersytet ?ódzki, ?ód?, Poland;5. Environment Agency, Dragonfly House, Norwich, UK
Abstract:River rehabilitation initiatives have become commonplace in European water courses as a result of European Union Water Framework Directive requirements. However, the short‐term responses of fishes to such work have thus far been varied, with some river rehabilitation efforts resulting in demonstrable improvements in diversity and size structure, whereas others have resulted in little or no change. Electrofishing and channel character surveys were conducted annually between 2009 and 2014 on a reach of the River Glaven (North Norfolk, UK) before and after rehabilitation work (embankment removal in 2009 and re‐meandering in 2010) as well as on a control reach immediately upstream. To assess the effects of rehabilitation work, before‐after‐control‐impact analysis tested for changes in channel character (geomorphology, substratum composition, and mesohabitat structure) and in fish species richness, relative abundance, population density, and size structure (calculated after fish data entry into the UK Environment Agency's National Fisheries Population Database). Following re‐meandering work (i.e., treatment), habitat heterogeneity and depth variation increased in the treatment reach, but fish responses were not significant except for biomass and density increases of brown trout Salmo trutta and abundance decreases of European eel Anguilla anguilla, in the treatment but not the control reach. These results are consistent with comparable river rehabilitation initiatives elsewhere, and they suggest that larger‐scale rehabilitations are probably needed to produce greater increases in fish density and diversity. It is recommended that future rehabilitation initiatives address catchment‐scale factors that can enhance ecosystem recovery, for example, removal of barriers to colonization, and increases in connectivity and water quality issues linked to eutrophication, elevated fine sediment inputs, and various pollutants.
Keywords:brook lamprey  brown trout  floodplain connectivity  rehabilitation  restoration  River Glaven
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号