Abstract: Orsolya ÁRENDÁS, Miklós BOZSÓ, Róbert GALLÉ, Attila Torma & László KÖRMÖCZI Orsolya Árendás, Miklós Bozsó, Róbert Gallé (contact author), Attila Torma, Dr. László Körmöczi, Department of Ecology, University of Szeged, Szeged, Pf. 51, H-6701 Hungary. E-mail: galle.robert@gmail.com Myrmecol. News 10: 100 The central region of the Great Hungarian Plain (Kiskunság) consists mainly of agricultural fields and small patches of natural forest-steppe. We studied the spatial changes occurring along a perpendicular gradient to a dense juniper bush-open grassland edge (site 1) and a poplar forest with a juniper bush-open grassland (site 2) edge. We used 100 pitfall traps at both sites, arranged in 10 parallel transects running from the grassland through the edge into the forest interior. The traps were operated eight times in 2004 and 2005. Each sampling period lasted for two weeks. Hierarchical cluster analysis and the Wilson-Schmida β-diversity index revealed that the ants exhibited abrupt changes in assemblage structure…