Response of wet grassland plant communities to water regime

Abstract

Lowland wet grasslands support a diversity of flora and fauna, yet in the UK the area of high quality habitat has been depleted due to agricultural intensification, particularly drainage. Development of agri-environment schemes is providing increased opportunities for restoration of degraded wet grasslands. Water level management is recognised as a key to the success of these initiatives. This research project aims to assess the response of lowland wet grassland plant communities to a change in water regime, including flooding. A review of previous research into wet grasslands demonstrated that water regime and vegetation management are critical for restoration and sustainable conservation of wet grassland plant communities. Field studies were undertaken at two locations in Sussex, England, where plant community response was analysed in using species abundance (cover and production), plant community structure and abundance of functional groups of species, using multivariate and inferential statistical techniques. The Pevensey Levels presented an opportunity to study the effects of in situ raised water levels on a twenty-one year chronosequence of sites, across a range of wet grassland plant communities and management types. ResuIts demonstrated the dynamic nature of plant communities at all hydrological regimes following raised water levels and that wet grasslands respond to flooding in particular, with effects differing between meadow and pasture management. Two experiments took place on West Dean Brooks, Cuckmere Haven. These were a reciprocal transplant study of plant communities characteristic of inundation and well-drained water regimes and an experiment to determine the impact of flood-borne deposition on plant community composition. Results of the reciprocal transplants study indicated that wet grassland plant communities were sensitive to water regime change and that vegetation developed on flooded sites was particularly dynamic. The deposition experiment showed that vegetation response to deposition depends upon depth of sediment and type of deposited material, related to the height of vegetation and competitive ability of species buried. Results are discussed in terms of implications for community concepts and dynamics, functional groups and key wet grassland species, and future prospects for restoration and sustainable management of wet grasslands.

Date of Award	Jan 2005
Original language	English
Awarding Institution	University of Brighton
Supervisor	Chris Joyce (Supervisor), Stephen Waite (Supervisor) & Daniel J. Metcalfe (Supervisor)