Prof Christopher Ramsey

Abstract:

© 2014 Elsevier Ltd. The research project 'Response of Humans to Abrupt Environmental Transitions' (RESET) used tephra layers to tie together and synchronise the chronologies of stratigraphic records at archaeological and environmental sites. With the increasing importance of tephra as chronological markers in sedimentary sequences, both in this project and more generally, comes a requirement to have good estimates for the absolute age of these volcanic horizons. This paper summarises the chronology of the key tephra in the RESET tephra lattice in the time range 10-60kaBP, from the existing literature, from papers produced as part of the RESET project, and reanalysis conducted for this paper. The paper outlines the chronological approach taken to the dating of tephra within the RESET project, and the basis for further work, as part of the INTIMATE (INTegrating Ice core MArine and TErrestrial records) initiative. For each of the tephra layers in the lattice, the existing literature is discussed and, where relevant date estimates updated using the latest radiocarbon calibration curves (IntCal13 and Marine13) and methods. Maps show the approximate extent of tephra finds, giving a visual indication of the coverage of the lattice in different time-periods.

Abstract:

Significance We present early evidence linking a high prevalence of caries to a reliance on highly cariogenic wild plant foods in Pleistocene hunter-gatherers from North Africa. This evidence predates other high caries populations and the first signs of food production by several thousand years. We infer that increased reliance on wild plants rich in fermentable carbohydrates caused an early shift toward a disease-associated oral microbiota. Systematic harvesting and processing of wild food resources supported a more sedentary lifestyle during the Iberomaurusian than previously recognized. This research challenges commonly held assumptions that high rates of caries are indicative of agricultural societies.

Abstract:

Radiocarbon dating of individual samples only yields limited chronological precision (typically of the order of 150–200 years for 95% confidence). This is in large part due to the complex nature of the calibration curve. Only by using large numbers of radiocarbon determinations together can we hope to resolve chronological issues at the sub-century level. Interpretation of such datasets is very difficult to do accurately by eye and for this reason statistical methods are needed. The methods most often employed are those of Bayesian analysis. Such methods do indeed allow us to improve our precision beyond that which is possible for single age determinations by radiocarbon but, critically, they also allow us to see the limitations in our data. In cases where statistical analysis shows that the radiocarbon measurements cannot resolve the chronological issues we need to accept that we must rely on other forms of archaeological information and interpretation.

Abstract:

Priority question exercises are becoming an increasingly common tool to frame future agendas in conservation and ecological science. They are an effective way to identify research foci that advance the field and that also have high policy and conservation relevance. To date, there has been no coherent synthesis of key questions and priority research areas for palaeoecology, which combines biological, geochemical and molecular techniques in order to reconstruct past ecological and environmental systems on time-scales from decades to millions of years. We adapted a well-established methodology to identify 50 priority research questions in palaeoecology. Using a set of criteria designed to identify realistic and achievable research goals, we selected questions from a pool submitted by the international palaeoecology research community and relevant policy practitioners. The integration of online participation, both before and during the workshop, increased international engagement in question selection. The questions selected are structured around six themes: human-environment interactions in the Anthropocene; biodiversity, conservation and novel ecosystems; biodiversity over long time-scales; ecosystem processes and biogeochemical cycling; comparing, combining and synthesizing information from multiple records; and new developments in palaeoecology. Future opportunities in palaeoecology are related to improved incorporation of uncertainty into reconstructions, an enhanced understanding of ecological and evolutionary dynamics and processes and the continued application of long-term data for better-informed landscape management. © 2013 The Authors. This is an open access article under the terms of the Creative Commons Attribution NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.