Marta Portillo

Morphometric Analysis of Inflorescence Phytoliths Produced by Avena sativa L. and Avena strigosa Schreb

Morphometric analysis, the study of measurements of size and shape, has the potential to be an effective tool for phytolith analysis. This study reports the first attempt to apply the methodology to oats. In particular, this study was designed to determine if morphometric analysis could adequately discriminate between phytoliths produced in the inflorescence bracts of two species of oats, Avena sativa L. and Avena strigosa Schreb. Results indicate that while the taxa produce the same types of phytoliths, those phytoliths have significantly different measurements of size and shape. This suggests the technique has the potential to become a powerful research tool for investigators working in the wide variety of disciplines that utilize phytolith analysis.

Tracing microfossil residues of cereal processing in the archaeobotanical record: an experimental approach

Interdisciplinary methodological approaches are fundamental for studying tool use and crop processing patterns in the archaeological record. Many archaeological studies of plant microfossil evidence, primarily those of phytoliths, starch grains and pollen, are concerned with processing methods which can be replicated through experimentally produced plant residues. However, most of these studies rely on crop identification through the presence or absence of such microfossils while giving little or hardly any weight to taphonomy and formation processes, which are critical for interpreting archaeological contexts. An investigation of experimentally produced phytolith and pollen assemblages provides the opportunity to evaluate the impact of cereal processing on both microfossils. Controlled experiments were conducted at the Museum of Menorca, Balearic Islands, Spain, for assessing microfossil taphonomy using Iron Age Talayotic tools and Hordeum vulgare (hulled barley) grown nowadays on the island. For dehusking, a sandstone mortar and a wooden pestle were used outdoors, whereas grinding took place indoors using a limestone quern and handstone. The results indicate that the size of multicellular or anatomically connected phytoliths decreases as a result of mechanical degradation suffered through processing activities, whereas the proportion of cereal pollen grains increases through these processes. Additionally, experimental samples from dehusking and sieving provided abundant evidence of floral bracts, and also of other plant parts and even different plant species, such as phytoliths from leaves and stems and non cereal pollen taxa, which were also to be found on the surfaces of the ground stone tools. These findings highlight the importance of integrating different lines of microfossil evidence and taking into account formation and taphonomic aspects, as well as the value of experimentally produced data for a better understanding of tool use and crop processing.

Blame it on the goats? Desertification in the Near East during the Holocene:

The degree to which desertification during the Holocene resulted from climatic deterioration or alternatively from overgrazing has puzzled Quaternary scientists in many arid regions of the world. In the research reported upon here, a multi-disciplinary investigation of a 5-m deep, ~11,000-year-old sediment column excavated in a dry lake bed in southern Jordan revealed an early interval in which proxies of plant cover and sheep/goat stocking rates co-varied directly with climatic cycles. Beginning ~5.6 kcal BP, however, this pattern changed with fecal spherulite and phytolith densities failing to co-vary and with spherulites often greatly exceeding phytolith densities, which we suggest is indicative of overgrazing. Moreover, the lack of agreement between the high phytolith densities and other indicators of a desert landscape (i.e. geomorphic and palynologic) suggests that phytolith densities were inflated by fodder subsidies and as such are not entirely reflective of plant cover for this later interval. Given the co-incidental emergence of overgrazing with archaeological evidence for a marked rise in regional population, emergence of widespread trade, and expansion of the Timnian pastoral complex during Chalcolithic–early Bronze times, we argue that desertification was a consequence of socio-economic factors (e.g. higher stocking rates) associated with a shift from a subsistence to a market economy. In addition, we contend that the signature lithic artifact variety (tabular scraper) that appeared in great abundance during this period was directly tied to the emergent market economy and its secondary products (wool) in having been used to shear sheep. Moreover, in that these changes took place largely concurrent with local and regionally recognized evidence of a moist interval, we conclude that the mid- to late-Holocene desertification of the southern Levant was induced more by anthropogenic than climatic factors.

The use of wild plants in the Palaeolithic and Neolithic of Northwestern Africa: preliminary results from the PALEOPLANT project

This contribution presents preliminary results from PALEOPLANT, a European Research Council (ERC) multidisciplinary research project that focuses on the analyses of plant remains from Palaeolithic and Neolithic sites in North Africa. The project aims are to: (1) characterize wild plant exploitation among human communities; (2) refine current knowledge on past landscapes; and (3) improve archaeological methodology and fieldwork when studying plants. We discuss preliminary results from charred plant macroremains (wood, seeds and fruits) and plant microfossils (phytoliths and calcitic ash pseudomorphs), as well as dung spherulites recorded in several northwestern African sites spanning the Late Pleistocene to the Early-Middle Holocene (c. 33 to 2 ka BC). Charcoal assemblages indicate the presence of mixed oak/juniper woodlands during the Late Pleistocene while conifers become the dominant element of the vegetation during the transition from Late Glacial to Early Holocene. In these contexts, some of the main species of thermo- and meso-Mediterranean Holocene landscapes (Olea europaea, Pistacia, etc.) were already present but their spread occurred during the Middle Holocene, concurrently with Neolithic occupations. The combination of wood charcoal, other plant macroremains (seeds and fruits) and plant microfossils, including both plant and dung indicators, provide new insights not only into the presence of a wide range of plant resources (wild pulses, Ziziphus lotus, Pinus halepensis, Quercus sp., Stipa tenacissima and Chamaerops humilis) but also on the variability of their potential uses (including fuel, food, fiber, bedding, fodder). Archaeobotanical results suggest continuity in the use of wild plants during the Neolithic. In addition, wood charcoal assemblages reflect significant changes that occurred in plant composition including the expansion of thermo-Mediterranean species.

Early animal management strategies during the Neolithic of the Konya Plain, Central Anatolia: integrating micromorphological and microfossil evidence

ABSTRACT This paper examines the contribution of microscopic multi-proxy approaches to the study of early husbandry practices and animal diet by integrated micromorphological, phytolith, and calcitic dung spherulite analyses of midden deposits at the three neighbouring Neolithic sites of Boncuklu (9th–8th millennium cal BC), Pınarbaşı (7th millennium cal BC) and Çatalhöyük (8th–6th millennium cal BC) in the Konya Plain, Central Turkey. The results reveal considerable chronological and contextual variation in human-animal inter-relations in open areas between different communities and sites. At Boncuklu, middens display well-defined areas where phytoliths and substantial accumulations of omnivore faecal matter low in spherulite content have been identified. By contrast, open spaces at the Late Neolithic campsite of Pınarbaşı comprise large concentrations of herbivore dung material associated with neonatal ovicaprine remains from spring birthing. Here, the deposits represent repeated dung-burning events, and include high concentrations of dung spherulites and phytoliths from wild grasses, and leaves and culms of reeds that, we suggest here, derive from fodder and fuel sources. Late middens at Çatalhöyük are characterised by thick sequences derived from multiple fuel burning events and rich in ashes, charred plants, articulated phytoliths – mainly from the husk of cereals, as well as the leaves and stems of reeds and sedges – and omnivore/ruminant coprolites, the abundance of the latter declining markedly in the latest levels of occupation. The application of this integrated microscopic approach to open areas has contributed to unravelling the complexity of formation processes at these sites, providing new insights into herding practices, diet, and the ecological diversity of Neolithic communities in Central Anatolia.