Plant species diversity and distribution along environmental gradients in a submediterranean forest landscape (central Italy)

A survey of a submediterranean forest landscape in central Italy was carried out to assess floristic diversity and species ecological behaviour in relation to some environmental gradients (altitude, aspect, light intensity on the undergrowth, soil pH, nitrogen content and texture). Diversity indices (species richness, Shannon-Wiener and Evenness) trends, calculated in relation to environmental parameters, showed to be mostly related to stress gradients. The highest diversity, in fact, is linked to the least stressful conditions. Redundancy analysis (RDA) allowed to identify six species sets, related to the environmental parameters, which were tested through bioindication values analysis. Intensity of stress factors and their combination select one or more groups of specieswithdifferentecologicalbehaviour, leading to the local floristic differentiation of plant communities. This approach may be useful to predict floristic variation of forest ecosystems as a consequence of increasing stress levels, such as drought stress due to climatic changes, to the definition of plant diversity conservation guidelines and for biodiversity monitoring.