1. School of Archaeology University of Oxford 36 Beaumont Street Oxford OX1 2PG UK
2. NERC Isotope Geosciences Laboratory British Geological Survey Keyworth Nottingham NG12 5GG UK
3. University of Connecticut Department of Anthropology Storrs CT 06269 USA
4. Center for Environmental Sciences University of Connecticut Storrs CT 06269 USA
5. Department of Agricultural and Food Chemistry Universidad Autónoma de Madrid, Ciudad Universitaria de Cantoblanco 28049 Madrid Spain
6. Department of Plant Biology, Ecology and Earth Sciences Universidad de Extremadura Plaza de Caldereros, s/n Edificio Rectorado 10003 Cáceres Spain
7. School of Social Science The University of Queensland St Lucia QLD 4072 Australia
8. Department of Agroecology and Environment Aarhus University Denmark