Classification and biodiversity patterns in pastures of province of Trento

In the Italian Alps, summer pastures are still managed in traditional ways, which maintain important grassland habitats of many species, although the number of pastures has declined drastically over the past few decades. Research on alpine pastures is important in many respects. From the aspect of nature protection, pastures represent a habitat for numerous plant and animal species; and, through their diversity, contribute greatly to the biodiversity and scenic value of the area. From the economic standpoint, grasslands are a source of feed for stock, a habitat for medicinal and melliferous plants. They are also capable of supporting particular dairy products, high added value, because fodder obtained from natural with unique qualities and not reproducible, capable of giving products derived valuable characteristics and identification. Land use changes constitute a threat to the persistence of these grassland ecosystems Therefore, it is very important to understand the mechanisms leading to the organization and distribution of these communities to preserve plant diversity and to develop effective agri-environment schemes, which can maintain and enhance biodiversity. Phytosociological investigation is important to understand some aspects of the study of grasslands. As in the forestry sector, also in grasslands sector have arisen in recent years some efforts to characterize, according to a typological approach, pasture vegetation. A purpose of this research was to realize an interpretative classification of pastures of Province of Trento. Since the pastures of the study area have not been systematically investigated for a long time, the pasture vegetation of the Province of Trento was classified using numerical methods, then the results were compared with the traditional syntaxonomic system, and finally were examined the influence of ecological factors on variation in grassland vegetation. Further aim of the research was assessed the relationship between topography, distance from the farm centre, altitude, bedrock, grazing intensity, species richness and vegetation composition across two spatial scales (within and between summer farms). A stratified random sampling design was used to collect 157 vegetation releves along an elevation gradient. It was hypothesized that plant diversity varies in response to topography due to the highly variable alpine environment and it depends strongly not only on grazing spatial gradient from the centres of the farms to the surrounding vegetation, but also on spatial distribution of the management practices within the study region The patterns of species richness and species composition found in alpine pastures result from the interaction of different environmental and management factors operating at different spatial scales. The results indicate that at small scales (within farms) species richness is mainly determined by slope, while specie composition is controlled by distance from the farm centre as well as slope. At large scale (between farms), was observed a key role of grazing intensity and bedrock types on species diversity patterns. The results indicate that the identification of appropriate stocking rates appears to be the most promising approach to conserve the high biodiversity of alpine pastures, as both intensification and abandonment changed species composition and reduced plant species diversity. Finally, to gain insight into the processes that may affect species diversity and functional diversity in alpine pastures, the observed local patterns of additive species diversity components (α-, β-, γ-) were analysed with respect to altitude, landscape, topographic hetereogeneity, bedrock type and grazing intensity. Additive diversity partitioning approach facilitated a quantification and comparison of the relative contributions of α- and β-diversity components to total regional diversity along an elevation gradient. Based on the results, I conclude that the observed patterns of plant species diversity appeared to be influenced by processes at multiple spatial scales. The results indicate that the maintenance of a large variety of grassland utilisation systems along with heterogeneous abiotic environmental conditions appears to be a promising tool for the conservation of species richness and functional diversity due to enhanced β-diversity among pastures parcels.