This study correlated the floristic composition of grassland communities with environmental variation in the Western Romanian Carpathians, focusing on the effect of grazing. Grasslands were sampled using 231 plots each 0.25 km2 in area. Vascular flora, altitude, aspect, slope, bedrock and grazing intensity were recorded for each plot. Data were processed using direct gradient analyses (CCA) and a generalized linear model. The results revealed three distinct communities associated with bedrock, landscape topography and grazing intensity. Grazing changes the floristic composition of grasslands on limestone more than on other types of bedrock. Specifically the floristic composition of the limestone-area plots subjected to low grazing pressure differ significantly from that of the plots of grassland on flysch and volcanic bedrock. When intensively grazed, the floristic composition of chalk grassland does not differ from that of the lightly grazed vegetation growing on flysch or volcanic bedrock. The reasons for this pattern and implications for management are discussed.
The role of clonal traits in a plant’s response to changes in management of semi-natural grasslands is poorly known and the few studies examining their importance have yielded contradictory results. For a better understanding of the role of plant functional traits in determining competitive ability and clonal growth in response to early changes in management, we mowed and applied fertilizer to 22 wet meadows in the Železné hory Mts, Czech Republic. We used two methods of assessing abundance (plant cover and species frequency) to determine whether changes in frequency induced by changes in management are better predicted by clonal traits while changes in cover are mainly determined by competitive traits such as plant height. We evaluated (i) the response of individual species to changes in management and (ii) the response of the whole community, with and without taking abundance of individual plants into account, in order to separate the effect of local extinction and immigration from changes in abundance. The plant functional traits tested were generally found to be important soon after the changes in the management of the semi-natural grasslands occurred: competitively superior resident species (possessing tall erosulate, monocyclic shoots) that are able to spread far and multiply clonally (having a high clonal index) were favoured by applying fertilizer and/or suppressed by mowing. Some other traits supposed to be important in the response to changes in management did not change (persistence of connection between ramets). Results for the two methods of assessing abundance differed; however, neither was better at detecting the response of particular types of traits (i.e. relevant to clonal growth and competitive ability). The initial response of the whole community, with and without taking abundance of individual plants into account, was consistent indicating that species that went extinct possessed the same traits as those that decreased in abundance. The clonal index proved to be a useful characteristic of meadow plants. Our results further imply that (i) the method used to assess abundance significantly affects the output of analyses of the response of functional traits, and (ii) a comparison of analyses based on weighting abundance and unweighted means resulted in a deeper insight into the changes in the spectra of functional traits that occurred after changes in meadow management.