Mitigating land degradation in Mediterranean agro-silvo-pastoral systems: a GIS-based approach

Agro-silvo-pastoral systems were studied in central–eastern Sardinia (Italy) to assess their environmental impact in marginal Mediterranean areas. Land cover changes between 1955 and 1996 were assessed by using multitemporal aerial coverages. The shift from extensive to semi-extensive production systems resulted in a decrease in woodland and in a marked increase in artificial pastures. Related field surveys highlighted widespread land degradation processes in areas where pasture amendment actions on land characterised by steep or fairly dissected morphology had been carried out. Starting from a past land suitability classification developed at farm level, a scheme for the evaluation of the land suitability to the creation of new pastures at regional scale was developed by using GIS methodologies. The scheme classifies the land into five land suitability classes as defined in the FAO Framework for Land Evaluation (highly suitable, moderately suitable, marginally suitable, currently not suitable, permanently unsuitable). The land suitability classification performed by the GIS model showed high accuracy if compared to the traditional procedure. The comparison between the land suitability and current land uses allows the identification of areas sensitive to land degradation where land resource conservation programmes can be proposed.