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This paper reports on the most ancient unusual morphological trait of the apertures of Poaceae pollen found in archaeological layers. In Poaceae, high levels of hybridization, polyploidy, apomixis, and multiporate pollen are often related. Multiple genomes in polyploids are critical for the adaptation of plant species to stresses and could be revealed by anomalies in pollen development. Therefore, the paleoenvironmental research can gain great benefits from identifying polyploids in past contexts by observing anomalous pollen morphology during pollen counts. The occurrence of multiporate pollen in Poaceae has also been related to special features of the ecology of the species showing this anomaly, as well as to climatic and environmental stresses experienced by Poaceae living in a given region. Multiporate and bi- or tri-porate instead of monoporate pollen grains have been observed in samples taken from Takarkori rockshelter, an archaeological site in southwestern Libya (central Sahara) that has been occupied between ~10,200 and ~4650 cal BP. Multiporate pollen was found in organic sands and coprolites of ovicaprines. On the basis of archaeobotanical research, this work aims to investigate whether the presence of supernumerary pores in Poaceae pollen may be an effect of both climatic/hydrological changes and continued anthropogenic pressure on the wild grasses living in the region. The presence of multiporate pollen reveals that Poaceae that lived in central Sahara tackled several kinds of stress during the early and middle Holocene. The Takarkori pollen record suggests that climate change could have played a major role in the early Holocene, while human pressure became stronger during the middle Holocene. The change in environmental conditions determined adaptive responses of polyploid grasses even in the form of multiporate pollen. [ABSTRACT FROM AUTHOR]

The palaeoclimatic evolution of northwestern Libya has been deduced from the study of the palustrine and aeolian sediments. The Holocene environmental variations have been recognized through geological and stratigraphic surveys and by pollen analysis and malacofauna content of the sediments. Some organic-rich horizons have been dated using the radiocarbon method. The data show that in general, the presence of marshes is linked with the period of higher humidity, which began around 9.4 ka BP and ended around 5.0 ka BP. From c. 5.0 ka BP up to about 4.4 ka BP, there was a simultaneous presence of marshes and vegetation of arid climate as a consequence of rainfall in the mountains and/or a decrease in temperatures. The Holocene wet period was interrupted by two arid spells dated about 8.2 and 5.5–5.4 ka BP. The end of the wet phase must have been gradual. The climatic events that occurred in the Jefara plain seem to be well correlated with those identified in Saharan Africa even if the Mediterranean is only 100 km away. [ABSTRACT FROM AUTHOR]

Abstract: Pollen analyses of 13 archaeological sites in the Wadi Teshuinat area, in southwestern Fezzan, Libya, were synthesised to explore the potential contribution of palynological investigation to archaeological research in this area. During the Holocene, the sites were occupied by pre-Pastoral (hunter–gatherers) and Pastoral (pastoralists) cultures. Different pollen stratigraphies and floras characterised the diverse sites and the relevant cultural phases. Pollen data were reported by discussing the sites separately, and by combining them to interpret the regional data set. Emphasis was made on the anthropogenic pollen indicators and grasses, including large grass pollen grains (>40μm), which were considered evidence of plant transport into the site. These were ethnobotanical markers, human-made evidence of plant harvesting by hunter–gatherers, or of animal breeding by pastoralists. The disappearance of some wild cereals was also observed, consistent with increasing climate dryness and land exploitation. Macroremains were used as a parallel tool to better understand plant exploitation in the region. [Copyright &y& Elsevier]

Rock shelters in the central Saharan massifs preserve anthropogenic stratigraphic sequences that represent both a precious archive for the prehistory of the region and a powerful proxy data for Holocene palaeoenvironments. The geoarchaeological (micromorphology) and archaeobotanical (pollen analysis) approaches were integrated to investigate the anthropogenic sedimentary sequence preserved within the Takarkori rock shelter, a Holocene archaeological site located in the Libyan central Sahara (southern Tadrart Acacus massif). The site was occupied throughout the Early and Middle Holocene (African Humid Period) by groups of hunter–gatherers before and by pastoral communities later. The investigation on the inner part of the sequence allows to recognize the anthropogenic contribution to sedimentation process, and to reconstruct the major changes in the Holocene climate. At the bottom of the stratigraphic sequence, evidence for the earliest frequentation of the site by hunters and gatherers has been recognized; it is dated to c. 10,170 cal yr BP and is characterized by high availability of water, freshwater habitats and sparsely wooded savannah vegetation. A second Early Holocene occupation ended at c. 8180 cal yr BP; this phase is marked by increased aridity: sediments progressively richer in organics, testifying to a more intense occupation of the site, and pollen spectra indicating a decrease of grassland and the spreading of cattails, which followed a general lowering of lake level or widening of shallow-water marginal habitats near the site. After this period, a new occupational phase is dated between c. 8180 and 5610 cal yr BP; this period saw the beginning of the frequentation of pastoral groups and is marked by an important change in the forming processes of the sequence. Sediments and pollen spectra confirm a new increase in water availability, which led to a change in the landscape surrounding the Takarkori rock shelter with the spreading of water bodies. The upper part of the sequence, dating between c. 5700 and 4650 cal yr BP records a significant environmental instability towards dryer climatic conditions, consistent with the end of the African Humid Period. Though some freshwater habitats were still present, increasing aridity pushed the expansion of the dry savannah. The final transition to arid conditions is indicated by the preservation of ovicaprines dung layers at the top of the sequence together with sandstone blocks collapsed from the shelter's vault. On the contrary, the outer part of the sequence preserves a significantly different palaeoenvironmental signal; in fact, the surface was exposed to rainfall and a complex pedogenetic evolution of the sequence occurred, encompassing the formation of an argillic laminar horizon at the topsoil, the evolution of a desert pavement, and the deposition of Mn-rich rock varnish on stones. These processes are an effect of the general environmental instability that occurred in the central Sahara since the Middle Holocene transition. Finally, the local palaeoclimatic significance of the sequence fits well with Holocene regional and continental environmental changes recorded by many palaeohydrological records from North Africa. This highlights the potential of geoarchaeological and archaeobotanical investigations in interpreting the palaeoenvironmental significance of anthropogenic cave sediments in arid lands. [ABSTRACT FROM AUTHOR]

Abstract: The paper presents the large set of basketry and other worked fibre artefacts constituting the perishable artefacts assemblage from the Takarkori rock shelter. This site is located in southwestern Libya, central Sahara. Its well-preserved Holocene stratigraphy testifies to human occupations by foraging groups (Late Acacus culture; ca. 9000–7400 uncal years bp; ca. 8300–6100 BCE) and herders (Pastoral cultures; ca. 7400–4500 uncal years bp; ca. 6400–3000 BCE). The basketry collection includes 91 desiccated items. They have been divided into two distinct groups: basketry constructions and basketry elements (b-items: 53 fragments); ropes and other elements in the broad sense (r-items: 38 fragments). Stems were mostly used to make the b-items, while a fairly diversified set of materials was used for ropes and other elements. In a few cases, mixed animal and plant materials were also employed. SEM analyses showed some diagnostic characteristics such as epidermal stomata, phytoliths, hairs and vessels indicating monocotyledons. Many items were identified as Panicoideae, likely of the Setaria and Panicum types. Therefore, the main wild cereals collected for food and transported into the site also seem to have been the main plants used to make basketry. The only wooden item was attributed to Vitex. The majority of the basketry is made using the twined technique. Basketry remains were more common during the Late Acacus occupation of the site, possibly associated with wild cereal processing and storage, reinforcing the idea of a re-organization of food security towards a delayed use of resources. The basketry material could be interpreted as remains of large and open baskets to collect and store seeds. Decreasing availability of wild cereals, changes in resource exploitation and the nomadic mobility pattern may explain why a smaller number of basketry items was found in layers connected to the Pastoral phases of occupation. [Copyright &y& Elsevier]