Vegetation ecology of Castelporziano woodlands

In the present work the results of a three-year ecological study carried out in 11 forest sites of the CP Estate, are discussed. Three different data set, ecological-floristic, edaphic and microclimatic, have been collected through phytosiological relèves, soil profiles and microclimatic measurements. The Ellenberg model (1974) has been applied to the floristic matrix to obtain for each community indicator values for light, temperature, continentality, soil moisture, soil reaction and soil nutrients. A statistical treatment of data showed several significant correlations between ecological indicators of species and communities and variables of soil and microclimate measured in the field. In particular, a strong relationship between soil moisture indicator value and Available Water Capacity measured in the soils (AWC) has been found. Microclimatic data focus on a remarkable heterogeneity of the Castelporziano woodlands, showing different seasonal trends as well as different critical periods during the year. In particular, different associations can be ordered according to a gradient of a few correlated parameters: temperature, yearly thermic excursion, air moisture. The seasonal trend of different microclimatic parameters varies along this gradient, and it seems that not average values but seasonal variaton is the key factor in structuring vegetation. Microclimatic parameters are also correlated with chemical soil parameters: for instance, high soil temperature correlated with high soil water capacity increases microbial activity and consequently influences the cycles of nitrogen, carbon and phosphorus. The whole of the correlations suggests the strenght of the interactions existing between plant communities and environmental measured variables, indicating a rather coherence of the ecological processes in the forest habitat of the CP Estate.