Methods for targeting the restoration of grazing marsh and wet grassland communities at a national, regional and local scale

Abstract

Grazing marsh has been recognised as a key habitat in the UK, and included within the Biodiversity Action Plan structure. In the present research, the conservation value of extant English grazing marsh and its geographical variation were assessed, and a strategy for targeting restoration of grazing marsh developed. A two-stage approach was taken: Botanical species groups were targeted for restoration, and areas identified where this might be attempted. Those species commonest in the wet grassland biotope were defined and classified into species groups on the basis of (a) their established strategy, habitat requirements and life forms; and (b) their occurrence in described plant communities (National Vegetation Classification – NVC). Areas where restoration was practical were identified using co-occurrence mapping of species from both species groups and NVC communities, and the same method used to identify where marked declines in these groups had occurred since 1950. Using national databases (plants, birds, insects) and information on areas through which restoration schemes might be administered (e.g. the English Nature “Natural Areas”), six ecological attributes were derived enabling sites and areas to be ranked for restoration. Areas were also ranked by the total grazing marsh area they presently contained. Qualitative and quantitative rankings were compared. Ranked Natural Areas were assessed on the basis of the liability to flooding, altitude and land cover. Research identified two philosophies for targeting restoration, focusing either on high-quality areas where success is likely, or on degraded sites where relative gain in biodiversity may be greater.