CONSTRUCTED WETLANDS AND NATURE CONSERVATION

By reference to examples in the UK this paper examines the wildlife po tential of reedbed treatment systems, both in their ability to act as pollutant buffers to protect or create downstream wetlands of conserva tion importance and as wildlife resources in their own right. The cons traints of size, structural diversity, pollution stresses and design c riteria of constructed wetlands are evaluated in terms of wildlife con servation opportunities, and the more stringent water quality requirem ents for wildlife functions are discussed. As a case study example, th e paper examines in detail the South Finger Reedbed developed by The W ildfowl & Wetlands Trust. This system has been designed with the dual objectives of improving the quality of effluent from a large collectio n of captive wildfowl in order to buffer sensitive downstream wetlands and of creating a wetland habitat of nature conservation value. The p erformance of this system, constructed in 1993, indicates good treatme nt levels, with suspended solids reduction around 80% and BOD generall y above 60%. In terms of wildlife performance the system rapidly evolo ved to support a broad range of vertebrate and invertebrate species. T he paper concludes that constructed wetlands for waste water treatment can be designed and managed to achieve optimal wildlife potential if approached from an ecological perspective as opposed to a strictly eng ineering viewpoint. (C) 1997 IAWQ. Published by Elsevier Science Ltd.