Mid-term changes of dry grasslands with conservation management in the Hainburger Berge Mountains

Abstract

Our study focused on evaluating plant diversity and vegetation changes in the dry grasslands of the Hainburger Berge Mountains protected within the NATURA 2000 reserve Hundsheimer Berge. Traditionally, these grasslands have been managed through intensive grazing but have experienced significant land-use changes since the 1950′s, including a prolonged period of abandonment. We investigated rocky and xeric grasslands of Festuco-Brometea, and mesic grasslands of Molinio-Arrhenatheretea using six nested plot series of various spatial scales. We also resampled relevés that were initially recorded in 2007 and analyzed them alongside older relevés (1930–2001) from the Austrian Vegetation Database. The compositional data variation was primarily influenced by moisture and nutrient gradients along the first DCA axis, and soil reaction and light availability along the second DCA axis. Grazing intensity had a significant effect on species richness at small spatial scales, while at larger scales, habitat conditions played a more crucial role. A continuous successional development could be detected in grassland composition, leading to a denser vegetation canopy and increased moisture and nutrient availability. However, plot resampling since 2007 revealed only minor changes, primarily due to interannual dynamics rather than a clear directional trend. We conclude that the current conservation management of rocky and xeric grasslands is proving successful in maintaining grassland biodiversity as well as high number and proportion of endangered plant species. Controlling grazing intensity, involving more farmers, and implementing flexible rules for grazing, mowing, and subsidy eligibility, could be instrumental in achieving conservation targets in the future.