Mediterranean landscape changes: evidence from old postcards

Recent, rapid and often underestimated landscape changes have occurred over large areas in Mediterranean Europe. They are the result of major rural depopulation. Old photographs of landscapes taken at the beginning of the twentieth century (i.e. old postcards) and present-day photographs taken at the same places were compared in a 2500-km(2) area of southern France. Vegetation changes were analysed using transition matrices. During the 80-year study period, land uses and vegetation changed dramatically Woodland cover and tree height increased; but in contrast, the extent of cropped lands and rangelands decreased. Forest spread was heterogeneous, depending on initial composition of the vegetation, and locally dominant ecological and socio-economic conditions. Our data show that a Mediterranean forest can re-establish under humid climatic conditions and spread within a century, despite severe prior exploitation over several decades. These dramatic changes are liable to have biological and ecological consequences (e.g, spread of woodland species, threat against open habitat species, fire regime modification, deterioration in water resources), some of them being already perceptible.