MONITORING 20 YEARS OF INCREASED GRAZING IMPACT ON THE GREEK ISLAND OF CRETE WITH EARTH OBSERVATION SATELLITES

The degradation of permanent semi-natural vegetation and the resulting acceleration of soil degradation and erosion processes constitute maj or elements of land degradation in the Mediterranean basin. These elem ents are triggered by human activities rather than climatic conditions . The Greek island of Crete represents a characteristic case of land d egradation resulting from hundreds of years of intensive grazing and f ires. Since Greece joined the European Communities in 1981, grazing in mountainous regions has greatly increased due to subsidies that becam e available through the Common Agricultural Policy. Within a European Research Project on the use of satellite remote sensing for monitoring environmental change in Mediterranean ecosystems (DeMon-2: An Integra ted Approach to Assess and Monitor Desertification Processes in the Me diterranean Basin), we have initiated a study to monitor the impact of increased grazing pressure on two mountainous ecosystems in Crete. Th e approach is based on describing surface conditions and vegetation co ver over time with a long-term series of earth observation satellites. (C)1998 Academic Press Limited.