Successional changes of dry grasslands in southwestern Slovakia after 46 years of abandonment

Abstract

Dry grasslands are endangered by succession because of changes in management, soil conditions and abandonment. The successional changes in vegetation composition after 46 years of abandonment were subject of the study. The analyses were designed to minimize errors that could be caused by application of historical data. With the help of numerical classification, internal variation within the associations was evaluated. Using computer modeling in GIS, the suitable management model for dry grasslands was defined. The following impact of successional changes was observed: The cover of expansive woody species Crataegus sp., Prunus sp., Rosa sp.; non-native species Pinus nigra, Prunus serotina, Robinia pseudoacacia, Syringa vulgaris, Fraxinus ornus, and competitively strong species Bromus erectus, Calamagrostis epigejos, and Peucedanum cervaria increased. The covers of non-native species represent 29% of the total forested area. The Poo badensis-Festucetum pallentis communities are the most endangered. The species diversity, cover of Festuco-Brometea species and Red List species decreased significantly in this vegetation type. The area of grasslands has been reduced by 61.1% compared with 1949 levels. We defined the “core” zone with the highest abiotic potential for the conservation of the xero-thermophilous communities, where their long-term occurrence will not depend on the presence of the management interventions.