Spatial patterns of Mediterranean land abandonment and related land cover transitions

In Mediterranean France, land abandonment is a widespread change. To understand and predict the land abandonment process and its consequences, land cover change models are used. An essential step in the development of a land cover change model is the identification and quantification of the factors controlling land cover change. In this paper we present a change detection study using aerial photographs in combination with an extensive dataset of field data and geographical data, to identify and quantify these factors for a study area in Mediterranean France, 60 km west of the city of Montpellier. We distinguished 11 land cover change classes and 7 associated "time since abandonment" classes at a detailed scale. Several environmental and non-environmental factors were found to be important variables for the land abandonment process. Differences in soil class explain a large part of the land abandonment pattern and the associated transition paths and transition rates. Most abandoned lands are located on regosols and lithosols, which are marginal soils with respect to water holding capacity. Within soil classes, we could recognise different transition paths and transition rates. However, within the 55 years covered by this dataset detailed transitions from pioneer vegetation to vegetation higher in the succession, as described by other authors, were only found for a limited number of vegetation/soil combinations. We relate these slow transitions for some areas to ongoing grazing and for some other areas to irreversible degradation.