Hydrological and hydrochemical conditions characterising Carex chordorrhiza L. fil. (String Sedge) habitat in a Scottish riverine floodplain wetland

The hydrological and hydrochemical conditions which characterise one of the two known UK habitats supporting Carex chordorrhiza (a glacial relict, occurring in riverine wetlands) were quantified. The environmental data were related to structural measurements of the species, and the plant assemblages in which it occurred. The communities which contain C. chordorrhiza in Scotland are closely related to two wetland vegetation types quite widely distributed in Europe, but the fact that C. chordorrhiza shows a severely limited, and scattered, European distribution within this general community type suggests that it has highly specific habitat requirements. These include moderately reducing hydrosoil conditions and near-constant shallow inundation, both producing intermediate levels of stress. The results suggest that management aimed at maintaining such conditions, and preventing invasion of more competitive species into habitats which support C. chordorrhiza, is a pre-requisite for conservation of this species in boreal regions of Europe. (C) 2003 Elsevier B.V. All rights reserved.