Vegetation history in the Oukaimeden Valley. Human action and the evolution of the landscape

Résumé

The archaeobotanical (Palynology and Anthracology) analysis of eight series from Oukaïmeden Valley (Atlas Mountains, Morocco) shows an archaeobotanical record that has undergone climatic and anthropic changes for the last 5147 ± 55 years BP (4050 - 3780 call BC). Climatic changes have been detected and human impact has been observed on the environment as regards to the use and exploitation of the resources of the territory. The territorial context shows several archaeological settlements from the end of the Neolithic and the Bronze Age. Archaeobotanical information displayed an open vegetation landscape. Its composition reveals a dry and high-altitude mountain Mediterranean environment. At a lower height we find Mediterranean taxa. Riparian vegetation and deciduous forest appear related to the bottom of the valley. The development of the different taxa progressively defines a combination of wet and dry periods in a territory highly affected by its excessive use as pastures. This fact culminates with the development of scrub vegetation associated to an important phytodiversity loss. The variability of the identified fragments of charcoal defines a diverse collection of firewood following an altitudinal gradient in the studied area.