INFLUENCE OF MANAGEMENT CESSATION ON REEDBED AND FLOODPLAIN VEGETATION ON THE KLOOSTRI FLOODPLAIN MEADOW IN THE DELTA OF THE KASARI RIVER, ESTONIA

Abstract

. The practice of cutting and grazing seminatural meadows is diminishing in Estonia like in the rest of Europe. As a result, plant species diversity is decreasing and species composition is changing on these meadows. The extent and speed of changes depend greatly on the ecological conditions of the habitats. The influence of management cessation on reedbed, floodplain marsh, and floodplain meadow vegetation was analysed on a landscape transect in the Kloostri floodplain, West Estonia. The above-ground biomass and litter were measured in 20 sample plots along the landscape transect in 1996. The species composition and cover data were compared with those estimated nine years earlier, in 1987, when the area was still under management. Above-ground biomass of reedbed was 1900-2100 g/m?, which coincides well with the earlier data. The biomass of floodplain meadow communities was 300-800 g/m’. Litter was abundant and in most floodplain meadow communities its amount was higher than that of biomass. Using Ward’s method of the coefficient of squared Euclidean distance for ordination of the species cover data from 1987 and 1996, it was found that the vegetation of drier sites (on higher elevations) had changed most notably while there were no changes in the sample plots of reedbed. The species composition of floodplain communities had changed a little; a few species common for pastures had disappeared. Differences between plant communities had decreased, vegetation had become more uniform. The dominance of tall grasses and sedges had increased.