TML> Badarau, Alexandru - Sabin*, Mihai Constantinescu, Stefan Dezsi, and Florin Pendea. The Transylvanian Basin is a tectonic depression in central Romania that has a hilly relief and is surrounded by the Carpathian Mountains. The western part of this basin, because it is in the rain shadow of the mountains, is semiarid and has forest-steppe type landscape. Among the typical components of the area vegetation are grasslands dominated by Stipa sect. Stipa. These grasslands fall into two categories: xerophytic grasslands dominated by Stipa pulcherrima and St. lessingiana and mesophytic grasslands with S. stenophylla that have a "meadow steppe" type of vegetation. These grasslands are similar to those in other portions of the western Palearctis, but have a unique mixture of Submediterranean and Central European species. In addition, our data suggest that they are not saturated, possibly because some species have failed to cross the Carpathian Mountains. In the past, botanists have not distinguished between these two types of grasslands, whether in relatively pristine condition or in various stages of degradation. We shall demonstrate that they are distinct, using ordination techniques and a database containing more than 350 releves sampled by our team. In addition, we shall show that indices of biodiversity provide clear indications of the extent to which such grasslands have been degraded and the entropy of their structure increased by human activity.

Key words: degradation processes, forest-steppe landscape, ordination, Stipa sect. Stipa, xerophytic and mesophytic steppe grasslands