Drivers of functional and taxonomical diversity within fragmented grasslands

Seminatural grasslands are biodiversity hotspots in the increasingly fragmented Central European landscape. In consequence vegetation scientists and conservationists are looking for factors maintaining such diversity under the threat of land-use changes. In our study, we surveyed around 1200 grassland patches within a region of 400 km2 in the Železné hory Mts. (Czech Republic). According to field measures and remote sensing information these patches varied in terms of productivity, wetness, disturbance, size and connectivity and different historical trajectories. We evaluated the effects of these factors on both taxonomical and functional biodiversity, and community functional properties. As expected, taxonomic diversity was positively correlated with grassland area and connectivity and was also higher on traditionally managed meadows. This effect of management is nevertheless meadow type specific and is much more pronounced on wet compare to dry meadows. Functional diversity, such as taxonomical, is positively affected by meadow size, but on the contrary, is higher on dry meadows. Mown meadows host less clonal, smaller, earlier flowering species with lighter seeds, however there are considerable differences among habitat types. In addition, the decrease in meadow size has more negative effect on species richness in unmanaged meadows in contrast to managed ones. This indicates the high importance of traditional management for maintaining species diversity of smaller grassland patches which often represent important landscape elements maintaining connectivity but are mostly omitted in conservation planning