Contribuţii Botanice, XLIII, 2008 Grădina Botanică “Alexandru Borza” Cluj-Napoca THE RELATIONSHIP BETWEEN THE STRUCTURE OF GRASSLANDS FROM THE NORTH-EASTERN SLOPE OF THE VLĂDEASA MASSIF AND SOCIO-ECONOMIC ACTIVITIES Gheorghe COLDEA, Liviu FILIPAŞ, Sorina FĂRCAŞ, Adrian STOICA, Tudor URSU, Ana-Maria POP Institute of Biological Research Cluj-Napoca 48, Republicii str., RO-400015 Cluj-Napoca, Romania e-mail: icb@cluj.astral.ro Abstract: In this article we present the spatial distribution of plant communities from the north-eastern slope of the Vlădeasa massif, mapped at a 1:25000 scale, the most important environmental factors involved in the determination of the structural variability of grassland, as well as the relationship between their structure and socio- economic activities. The results from the canonical correspondence analysis (CCA) identify the presence of water and nitrogen in the soil as the main factors involved in the determination of the pastures’ eco-coenotic variability. Nitrogen content in the soil is directly influenced by socio-economic activities, respectively by the different use of the fields (pastures or hay meadows). As a result, the phytodiversity of plant communities is influenced by their management. The highest phytodiversity is that of the Poo-Trisetetum flavescentis association, which is maintained artificially by traditional land use (periodical fertilization), depending on the quantity of hay that is needed, while the lowest phytodiversity is that of the Violo declinatae-Nardetum association, used as a pasture. Key words: montane pastures, phytodiversity, CCA Analysis, socio-economic activities Introduction The semi-natural grasslands from the sub-alpine area are the habitats with the highest plant diversity in Europe (Kull and Zobel, 1991). Their areas are continuously diminishing because of abandonment of practices that led to their appearance or because of changes in their management. Numerous studies report a significant decrease in biodiversity correlated with changes in traditional land use practices (Pimm et al., 1995; Hannah et al., 1995; Michelsen, 2003), with the decline of socio-economic activities in the region (Austrheim et al., 1999), or by their intensification (Vandvik and Birks, 2002). In this study we have identified in the field the plant communities and delimited their areas in order to draw the vegetation map at a 1:25000 scale for the north-eastern slope of the Vlădeasa massif. Also, by multivariate analysis of data collected in the vegetation period of the year 2007, we have sought to reveal the relationships between the floristic structure of pastures, environmental factors and socio-economic activities. Materials and Methods The studied perimeter is located on the north-eastern slope of the Vlădeasa Massif (Apuseni Mountains) and includes the lower basin of Valea Henţului. Here, in the Western part of Cluj county, there are 6 rural localities (Bologa, Traniş, Valea Drăganului, Vişag, Săcueu, Rogojel) whose number of inhabitants varies between 362 and 1735. Like in most mountain settlements, the range of socio-economic activities is dominated by livestock raising (sheep and cattle). The vegetation units for mapping have been established by doing releves in 1 square kilometer grid cells.