Abandonment and reinstated management upon coastal wet grasslands in Estonia
Berg, Maureen Jennifer
PublisherUniversity of Brighton
MetadataShow full item record
Abstract Coastal wet grasslands are internationally important habitats as they support high biodiversity. The combination of periodic flooding, fluctuating ground water and regular low-intensity management has created a unique habitat providing ecological niches for a wide diversity of flora and fauna. This habitat, however, is globally threatened due to changes in land management, particularly agricultural intensification or abandonment. In Estonia, agricultural abandonment such as grazing cessation has been recognized as the main cause of coastal wet grassland losses, which results in the encroachment of shrubs and competitive grasses (e.g. Phragmites australis, Elytrigia repens). This research assessed the response of coastal wet grassland plant communities to abandonment and management practices, namely cutting, grazing and soil disturbance. Changes in vegetation composition and abundance were monitored using species and functional groups, and then analysed using multivariate and inferential statistics. Three experiments were located in western Estonia: (i) to compare the responses of species-poor and species-rich wet grasslands to cutting management (Hosby), (ii) to investigate changes in upper shore grasslands under different management practices (i.e. abandonment, cutting and grazing) and in response to reinstating management (Tahu), and (iii) to assess the effects of different levels of disturbance on encroaching grass species and the composition of wet grasslands (Rumpo). Results demonstrated the dynamic nature of coastal wet grassland plant communities as seasonal variations and environmental conditions affected the plant community composition and abundance. A species-rich grassland showed greater stability in response to cutting management when compared to a species-poor community, as more significant changes in species composition and abundance affected the species-poor vegetation. Upper shore grasslands demonstrated similar patterns in plant community changes and composition under different management practices, although cutting positively affected some species and created bare ground. The similarities between abandoned and grazed upper shore grasslands indicated that the grazing intensity practised might not be sufficient to maintain the plant community at an earlier successional stage. Wet grassland responses to disturbance were dependant upon the intensity of disturbance and the type of vegetation, in relation to the competitive ability and sensitivity of the species present, but the effects of disturbance upon encroaching grasses were insignificant after a year. The results of the research provide a better understanding of the dynamic nature of coastal wet grasslands and the implications of management practices for the restoration and conservation of coastal wetlands.