Historical review of land use changes in Portugal (before and after EU integration in 1986) and their implications for land degradation and conservation, with a focus on Centro and Alentejo regions

Changes in land use and production systems are to a large extent responsible for land degradation. In Portugal this process has been triggered mainly by socioeconomic drivers, such as agricultural technology, demography and policy changes. In this article land use changes in Portugal are discussed in terms of their main drivers and impacts, focussing on land degradation and conservation. The discussion includes a brief outline of historical land use changes in Portugal and a more detailed account of the changes in the period after 1986, when Portugal joined the European Union. An assessment of recent (1986-2006) land use changes and their impact was conducted for two selected research areas in the Centro and Alentejo regions. This assessment was based on information from the CORINE Land Cover programme (1985 and 2006) and the National Agricultural Census (1989 and 1999). In the Centro research area the land under forest declined from 52% to only 22% of the area, mainly as a result of forest fires. In the Alentejo research area the major change was the decline of miscellaneous shrub, declining from 23% to 11%, to open forest land, increasing as a result of afforestation measures from 1% to 22%. These land use changes resulted in a significant increase of soil loss estimates through RUSLE. In the Centro research area soil losses greater than 10 t ha-1yr-1were estimated to occur in 57% of the area in 1990, increasing as a result of land use change to 64% in 2006. In the Alentejo research area this change was from 65% in 1990 to 72% in 2006. The research raises questions regarding land use management, in relation to the Common Agriculture Policy support during the 1986-2006 period. Despite the increase in forest and permanent grassland areas, soil loss rates remain very high in the two research areas.