Assessment of floristic diversity, functional composition and management strategy of North Adriatic pastoral landscape (Croatia)

European semi-natural calcareous grasslands are species-rich ecosystems, considered as priority habitats by the European Union (92/43/EEC Directive) and judged worthy of conservation. They are in strong decline in extension and are threatened by abandonment throughout Europe. It is known that grasslands management (grazing, mowing) acts as driving force in plant community diversity, which in turn is an important conservation aim of European environmental policies. The area of current pastoral landscape (about 1000 ha) of the North Adriatic (Æiæarija, Croatia) was studied in order: 1/ to understand which factors drive floristic differentiation – environmental features and/or grassland management conditions, 2/ to identify indicator species sets linked to those factors and 3/ to appraise the effects of management type on the coenological and functional composition of indicator species. 73 phytosociological relevés were carried out; for each of them field data (altitude, aspect, slope and land form), productivity measurements and information on grassland management were collected. Redundancy analysis (RDA) identified a productivity-related soil moisture gradient as the environmental driving force of grassland floristic differentiation. Indicator species analysis (ISA) detected the indicator species sets related to environmental features and management type. The results indicate that undergrazing and the lack of periodic mowing are responsible for the higher total variance of floristic data set explained by environmental parameters rather than by management (use/not use). For the same reasons, the variations that emerged from comparison of the functional characteristics of the indicator species of grazing and of mowing (avoidance strategy, life form, and storage organs) proved more important than those observed in comparing used and abandoned grasslands. The management system adopted (grazing or mowing) appears in turn to be conditioned by the soil moisture/productivity gradient.