Authors: Gallé, Róbert; Korányi, Dávid ;Tölgyesi, Csaba;Lakatos, Tamás;Marcolin, Fabio;Török, Edina;Kuli-Révész, Kitti;Szabó, Ágota;Szitár, Katalin;Torma, Attila;

As a consequence of agricultural intensification, grassland biodiversity has declined considerably in Europe. We assessed how variation in fragment size (small vs. large) and landscape configuration (connectivity index), affect plant and arthropod diversity. We studied two threatened grassland ecosystems in the Hungarian Great Plain, 30 forest steppes, and 30 burial mounds (kurgans). Forest-steppes are natural mosaics of undisturbed dry grasslands and small patches of forests in a matrix dominated by plantation forests. Kurgans are ancient burial mounds that harbour moderately disturbed natural grasslands surrounded by agricultural fields in the Eurasian steppe and forest-steppe zone. We focused on the diversity pattern of plants, spiders, true bugs, wild bees, and wasps. We found that fragment size, connectivity, and their interaction affected species and generalist species abundances of forest-steppes and kurgans. Large fragments had higher species richness, and the effect of connectivity was stronger positive for specialist arthropods and stronger negative for generalists in large than is small fragments. However, we also found a strong positive impact of connectivity for generalist plants in large kurgans in contrast to smaller ones. We conclude that enhancing connectivity between fragments by increasing the amount of natural and semi-natural habitats via restoration would help maintain grassland biota