New pollen data from the Uan Muhuggiag rockshelter (Libyan Sahara, VII-IV millennia BP).

The Uan Muhuggiag rockshelter (24°50'32''N 10°30'47''E; 900 m a.s.l.) is a pastoral site which provides primary archaeological evidence and a key series for palaeoenvironmental reconstruction of the Central Sahara. Based on new systematic sampling, stratigraphical, micromorphological and palynological research was carried out on this series. This paper presents the pollen diagram obtained from 11 samples taken in the series. Based on 14C dates, the pollen sequence covers a time span ranging from VII to IV millennium BP. A total of 118 pollen types belonging to 48 Families were recorded, out of 5,600 identified pollen grains. Well-preserved pollen grains prevailed; only sample no.7, rich in charcoal fragments, had a few and badly preserved pollen grains. The pollen diagram was consistent with the 14C chronology and three main pollen zones were identified in it. The bottom Zone (UM1) showed that a savanna vegetation was spread in the area (Gramineae and Cyperaceae) and suggested a permanent water source near the rockshelter, testified by hydro/hygrophilous plants (Typha, Potamogeton, Phragmites, Scirpus ). In Zone UM2, the vegetation was still open, but shrub and tree cover increased. The water environment was reduced. In Zone UM3, shrubs and herbs prevailed and a desert savanna together with typical wady communities and psammophylous plants finally emerged. Pollen assemblages, mainly in zone UM3, testified that the mid-Holocene vegetation cover was larger than today's, and flora was more various, characterized by a mixture of tropical and Mediterranean-Saharan-linking pollen types. The pollen diagram was consistent with previous studies on the rockshelter which had concerned both pollen and macrofossils, and provided more information about the mid-Holocene vegetal landscape in the area. Throughout the diagram a disturbance produced by human occupation was observed, increasing in Zone UM3. It was due to the pressure of grazing from domestic animals which accentuated the changes in vegetation induced by the climate, and also to the overrepresentation of some pollen types which had been carried by coprolites and harvested plants inside the rockshelter. Among these plants, Panicum cf. (millet) and Cereal pollen-type I (sensu Bottema) were found, suggesting the harvesting of wild caryopses. The wild flora/vegetation of Uan Muhuggiag appeared to have well supported the food needs of neolithic people during the mid-Holocene, from VII millennium to IV BP, even in the latter period which was characterized by arid climatic conditions.