CHANGES IN BOTANICAL DIVERSITY OF SOWN GRASSLANDS DUE TO NATURALIZATION AND EXTENSIVE MANAGEMENT

The paper deals with sown grassland naturalization models related to changes in botanical diversity of extensively managed meadows under temperate climate conditions. The vegetation surveys were carried out in S?li?k?s and Polyma Experimental Field Stations (Lithuania). Based on our research data and literature sources (on the investigation of Lithuanian natural meadows), we developed the following hypothetical models of sown grassland naturalization: vascular plant species constancy alteration chronocline, vascular plant species constancy and productivity alteration topocline and a scheme of sown grassland naturalization on hilly landscape. Here we consider extensive management and naturalization as one of most natural and requiring minor investments method for grassland restoration.