Integrated Microscopy Approaches in Archaeobotany: proceedings of the 2016 and 2017 workshops, University of Reading, UK

The collection of papers in this special issue arises from research presented at the 2016 and 2017 workshops in ‘Integrated Microscopy Approaches in Archaeobotany’ held at the University of Reading, UK. The aim of the workshops was to bring together students and specialists in geoarchaeology, biogeochemistry, anthracology and other plant macroremains, palynology, non-pollen palynomorphs and phytoliths who are working in universities, major heritage organisations, curatorial bodies, and commercial archaeology companies in order to share research and skills. Since then, the IMAA workshops have been successfully celebrated in Reading every year, testifying to the growing interest for archaeobotanical microscopy approaches in conjunction with other proxies, and particularly from the field of geosciences.

Archaeobotany is the study of archaeological plant remains, which include macroremains, such as seeds and wood charcoal, and a range of associated microfossils, such as phytoliths, pollen, spores and starch grains. These papers showcase a range of microscopy approaches that can be applied to examine and interpret botanical and organic assemblages in the archaeological record, and to address a range of topical research themes and current debates in archaeology, such as environmental management, human responses to environmental change and sustainable life-ways spanning a broad geographical and chronological time periods. Soil micromorphology is a technique that enables the formation and post-depositional processes of archaeological deposits to be understood by reconstructing sediment histories. It allows archaeobotanical remains to be examined within their depositional context to provide a micro-contextual interpretation of the evidence, and to understand different types of archaeobotanical remains in a range of preservation conditions (e.g. Matthews 2010; Vrydaghs, Ball, and Devos 2016; Ismail-Meyer 2017; Ismail-Meyer, Stolt, and Lindbo 2018). As with many other proxies, formation processes and taphonomy are key issues in the study of any type of plant remains (e.g. Van der Veen 2007; Matthews 2010), and this is reflected in several contributions of this volume.

Banerjea et al. and Borderie et al. address a paucity of multi-proxy environmental archaeological studies on European castle sites from the medieval period, and enhance our understanding of the earliest phases of their occupation. In both papers, the integrated results have allowed the potential of these proxies to be powerfully exploited to show new archaeobotanical perspectives on the function and development of castle complexes and their relationships with the castle's hinterland.

Banerjea et al. use soil micromorphology, plant macroremains, phytoliths and palynology results from two castles in the Baltic (Elbląg, Poland, and Karksi, Estonia) to show changes in animal husbandry through time, whereabouts within the castles the animals were stabled, and livestock alimentation. The study represents an important investigation of deposits from medieval castles, particularly from the period of active crusading, which are rarely revealed through excavation and, in the past, have seldom been subjected to an integrated environmental investigation.

Borderie et al. use soil micromorphology, plant macroremains and phytoliths, including their morphometric analysis, to provide new evidence of the richness and the complexity of the town of Gien (France), and of the activities which could take place within early castra, such as the use of floor preparation materials, the maintenance practices, and domestic, metallurgical and animal husbandry activities. Morphometric analysis of phytoliths in micromorphological thin sections showed cultivated cereals which were processed in situ, such as Triticum durum, Secale cereale and Hordeum vulgare.

The paper by Vrydaghs and Devos propose a system for the simultaneous observation and description of phytoliths in thin sections of soils and archaeological sediments. It presents three aspects of phytoliths in thin section, namely VPC index: (V) visibility, expressing to what extent these are masked and/or surrounded by fine material; (P) preservation, as indicator for the physic-chemical alterations that affected them; (C) colour, describing the extent to which the phytoliths are coated by other particles and indicator for the charring of the organic material surrounding them. This paper presents an important contribution towards the standardised description and recording of phytoliths in thin section to facilitate comparison and interpretations of microfossil datasets from different sites and research areas.

A good knowledge of livestock management and herding practices is crucial when investigating the subsistence of farming societies. These aspects do not always have a good visibility within the archaeological record, so that archaeobotanical evidence should be employed to shed light on them, along with other analytical techniques including contextual micromorphology as above outlined, and direct microscopic dung indicators such as calcitic spherulites, coprophilous fungal spores, isotopic and biomolecular signatures, along with zooarchaeological remains from different origin. Of particular interest for unveiling pastoral and agro-pastoral activities in archaeology is understanding the nature and taphonomy of animal dung remains, which is in this issue explored in archaeological and modern ethnographical contexts through the use of direct and indirect proxies of various origin, including in vegetal micro-remains such as opal phytoliths and calcium oxalates, as well as faecal indicators such as fungal spores and calcitic spherulites that form in the digestive system of a variety of animals (e.g. Shahack-Gross 2011; Friesem 2016, and references therein).

Two papers deal with both ethnoarchaeological plant and dung microfossil evidence for livestock management (Dalton and Ryan; Morandi).

The study of Dalton and Ryan on a New Kingdom pharaonic settlement in Sudan combines dung spherulite and phytolith analyses of desiccated and charred ovicaprid dung pellets as well as faecal material in thin sections, with further support provided by micromorphological evidence and chemical signatures. Their experimentally produced datasets from modern reference materials suggest differences in dietary calcium intake and feed Ca availability implicated in dung spherulite crystallization within ovicaprid digestive tracts, thus providing new insights into spherulite formation, aspects poorly-defined to date.

Analysing a sequence from a recent pastoral cave context in northwestern Italy, the paper by Morandi also follows an integrated approach combining direct faecal microfossil indicators from calcitic spherulites and coprophilous fungal spores, which are more widely utilised in wetland palaeoecology to assess past herbivore presence (Johnson et al. 2015; Baker et al. 2013). This study highlights the contribution of ethnoarcheological approaches to understand microfossil taphonomy and their distributions within penning cave deposits.

The paper by García-Suárez, Portillo and Matthews presents micro-contextual studies in open site areas through simultaneous examination in thin section micromorphology and integrated phytolith and dung spherulite analyses for the identification of early animal management strategies in the Konya Plain, a key region in the origins and spread of Neolithic innovations in Central Anatolia, Turkey (e.g. Hodder 2006; Baird et al. 2018). Dung assemblages are identified at high-resolution studies from midden deposits at the early agricultural site of Boncuklu, as well as at the later occupations of Çatalhöyük and the Late Neolithic settlement of the Pınarbaşı rockshelter, thus proving direct evidence for animal management, diet and ecological diversity, as well as for site formation and organisation of the space of early settled life. In sum, all three papers within this section show the potential of archaeobotanical microfossils and other micro-remains for reconstructing livestock management, animal diet and potential indicators of seasonality.

No proxy record has the ability to enable reconstruction of past landscapes in isolation. However, substantial on-site archaeobotanical macrofossil assemblages including charcoal do offer the opportunity to examine aspects of the local landscape and presence/absence of exploited habitats across the wider source area (Chabal 1997; Asouti and Austin 2005; Théry-Parisot, Chabal, and Chrzavzez 2010). The presence of charred wood on an archaeological site relies on it having been gathered and transformed through use or discard, and so its examination can also provide insights into a range of human activities and targeted resource exploitation (Smart and Hoffman 1988; Théry-Parisot, Chabal, and Chrzavzez 2010). Despite these opportunities for knowledge gain, analysis of charcoal, and to a degree other on-site macroscopic proxies, such as mollusca and coleoptera, are often overlooked, underestimated or felt to be a poor relation of plant macrofossil analysis as a tool in archaeological studies.

Reflection is made in the paper presented in this volume by Barnett on whether systematic, large-scale, analysis of wood charcoal is of significant value in understanding landscape, resource use and lifestyles at and around Iron Age Silchester, Hampshire, UK, and the wider implications of that reflection are considered. Barnett's paper shows that anthracology has high potential to inform not only on the presence of tree and shrub taxa in the past but also on the structure and location of former woodlands, heathlands and wetland fringes.

Lastly, Portillo and colleagues present an extensive and up-to-date review of the literature dedicated to morphometric investigations in archaeobotany. Over the last few decades, morphometrics have particularly contributed to the study of the domestication and spread of many crops around the world, such as cereals and legumes, underground storage organs (USO), and a wide range of fruits (e.g. Terral et al. 2004, 2010; Willcox 2004; Fuller 2007; Fuller et al. 2017; Ball et al. 2016, and references therein). This paper presents an overview on current methodologies, recent applications, and advances in the use of morphometrics for various types of plant remains (mainly seeds, pollen, phytoliths, and starch grains), its applications for improving taxonomic resolution, and discusses its contributions to addressing major research questions, challenges and possible future directions in archaeobotanical research.

Collectively, the papers explore ways to address the challenges of integrating and presenting datasets that were recovered from (a) multiple sites and (b) through different types of excavation, often within the same project. Arising from these issues stems a necessity to understand the sampling and data interrogation requirements of fellow specialists. Overall, the articles included in this volume illustrate a range of perspectives by which microscopy approaches in archaeobotany contribute to address main research questions and current debates in archaeology, making these studies a valuable research tool especially when integrated with other proxies.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Rowena Yvonne Banerjea, a post-doctoral researcher at the University of Reading, writes on the application of geoarchaeology to understand the formation processes of the archaeological record, and to understand frontier landscapes in medieval Europe. Rowena has publications on these topics in the journals Antiquity, Geoarchaeology, Journal of Archaeological and Anthropological Sciences, Journal of Archaeological Science, and Quaternary International.

Catherine Barnett is a Senior Research Fellow at the University of Reading and Co-Director of the Silchester Environs Project. She is an archaeological scientist, focussing on prehistoric landscape archaeology and specialising in archaeobotany (wood and charcoal analysis) and geoarchaeology (gross sediments).

Lionello F. Morandi holds a Doctorate from the University of Reading, and is currently post-doctoral researcher at the University of Tübingen. His research interests are wide, and he is actively involved in a number of projects ranging from Etruscan archaeology to the archaeology of death, ethnoarchaeology, palaeodemography and palaeoenvironmental reconstruction.

Marta Portillo was a Marie Sklodowska-Curie fellow at the University of Reading. She is an environmental archaeologist whose research focuses on the developments of cultural, economic and technological behaviours in the Western Mediterranean and the Near East, with particular interest on the emergence of sedentism and early agricultural life-ways. She is specialised in phytoliths in integration with geoarchaeological methods, as well as with experimental and ethnoarchaeological approaches. She serves at the board of the International Phytolith Society (IPS).

ORCID

Rowena Y. Banerjea http://orcid.org/0000-0002-1786-357X

Catherine Barnett http://orcid.org/0000-0002-6156-1640

Lionello F. Morandi http://orcid.org/0000-0001-8840-6096

Marta Portillo http://orcid.org/0000-0002-2703-031X

Additional information

Funding

Funding, administrative and technical support has been provided by the School of Archaeology, Geography and Environmental Science for the successful development of the IMAA workshops, and we thank the Association for Environmental Archaeology, Beta Analytic and Quaternary Scientific (QUEST) for their sponsorship. The 2017 workshop also received funding from the University of Reading's Endowment Fund. Rowena Banerjea's research was carried out within the framework of The Ecology of Crusading project, which received funding from the European Union’s Seventh Framework Programme (FP7/ 2007–2013) under grant agreement No. 263735. Catherine Barnett's research was funded by the Calleva Foundation as part of the wider Silchester Environs project. The work of Marta Portillo was carried out within the framework of the EU Horizon 2020 MICROARCHEODUNG project. This project has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No. H2020-MSCA-IF-2015-702529.