Land Use Trajectories for the Assessment and Sustainable Management of Land Degradation

Abstract

Land degradation (LD) is regarded as one of the most important processes leading to environmental degradation. LD specifically refers to a reduction in terms of economic productivity and capacity of providing ecosystem services by cropland, rangeland, and woodlands. Archetypal patterns or "syndromes" of LD can then be evaluated in the past, and scenarios developed for the future, informing sustainable land management strategies. Land cover is the visible result of the interactions between natural and socio-economic systems. It often reveals the occurrence of LD, either because it bears a direct effect on the processes or because it is associated with unsustainable land uses. Land use and land cover (LULC) are therefore essential for interpreting change trajectories associated with LD and deriving prediction rules. Whenever available, LULC data providing comparable classifications as well as the needed spatial resolution and time coverage can be derived from existing thematic cartography. In alternative, a procedure for the semi-automatic generation of LULC data from archive Landsat (7,5) satellite imagery since the mid-eighties, is under development. The procedure combines pixel and object oriented classifications and makes use of multi resolution segmentation for down dating and updating procedures. Past trajectories in LULC are analysed at regional level together with trends in other relevant drivers, for investigating associated land degradation syndromes (e.g. urban sprawl and soil sealing, aridity and climatic aggressiveness, water and soil erosion, agricultural pressure) through quantitative indicators of vulnerability (e.g. ESAI-Medalus, ESI LADA-FAO) and more "narrative" and participative interpretations (e.g. "story lines"). Climatic forecasts, population projections, as well as land use modelling are also used for developing LD scenarios.In the context of the research project AGROSCENARI (Scenarios of agriculture adaptation to climate change) promoted by the Italian Ministry of Agriculture, the research line "Land Degradation Processes and Climate Change" intends to investigate trajectories and syndromes as well as scenarios of land degradation, especially in face of climate change, in a number of test areas in the country. Methodological issues and preliminary results are discussed in this paper, with particular reference to the case of the Emilia-Romagna Region and to degradation processes associated to urban growth and sprawl.