AGRICULTURAL TERRACE ABANDONMENT IN THE ALPUJARRA, ANDALUSIA, SPAIN

The environmental impact of recent changes in land use is assessed in a part of Andalucia, southern Spain, where the deintensification and a bandonment of low productivity upland areas is taking place. In the up lands of the Alpujarra, the traditional landscape most at risk is that of the irrigated cultivation terraces. These have often been establis hed centuries ago and rely on water abstracted from streams draining t he southern slopes of the Sierra Nevada. The causes of this deintensif ication include labour shortages, which many Alpujarra municipios repo rting population decreases of up to 50 per cent since 1950. Landsat Th ematic Mapper digital data from May and August 1992 have been used to identify the various land cover components of the Alpujarra. Ground ve rification undertaken in September 1992 and April 1993 has confirmed t hat deintensification of terraced areas around the villages of Trevele z (at 1500 m, the highest village in Spain) and Portugos (1300 m) can be identified as either grassland or matorral. It is recognized that m any classes of land cover are mosaics with several elements at a subpi xel scale (e.g. terrace risers with fruit trees). However, the output from image processing has allowed areal estimates of the main land cov ers representing deintensification within the terraced zone. The patte rn of deintensification of terraced land is fairly complex. It can be assumed that all terraces were irrigated and cropped at some stage. La nd which is no longer cropped is usually grazed and the invasion of ma torral species is common, particularly when irrigation ceases. Unirrig ated tree crops and vines are sometimes planted on terraces no longer used for cropping. A model of deintensification of farming on terraced land in the Alpujarra is presented.