HUMAN IMPACT ON THE VEGETATION OF THE MIDDLE ATLAS, MOROCCO, DURING THE LAST 5000 YEARS

Pollen and magnetic mineralogical analyses of sediment cores from lakes in the Middle Atlas region of Morocco provide evidence for vegetational disturbance, almost certainly anthropogenic, since about 5000 BP. Localized periodic clearances of pine are recorded at Dayat Iffir before a major episode of pine clearance and soil erosion at about 2000 BP. Catchment disturbance at this and two other sites intensified about 1500 years ago, as arable farming increased in a predominantly pastoral economy. Because evergreen oak resprouts after cutting or burning, it has become the dominant forest tree in much of the region. Deciduous oak, once abundant, has become rare. Locally, the abundance of cedar has decreased. Overall, the forests have become less diverse, more open, and scrub-dominated as a result of human exploitation.