Sediments from the lake site of Marcacocha in the Peruvian highlands have recorded a detailed palaeoclimatic history for the region over the last 4000 years
The Andes are recognised as a major centre of biological and cultural diversity that have witnessed the rise and fall of numerous civilisations over the past few millennia. As such, the area has received increasing attention from researchers interested in addressing a variety of cultural, climatic and ecological issues over a range of timescales. In South America the last two thousand years are of particular interest, since they encompass a sustained period of significant cultural turnover and societal evolution, culminating in the rise to power of the Inca Empire (AD 1400-1533), the largest and most sophisticated indigenous state ever to develop on that continent. Crucially, this phase of dynamic social development was played out against a background of major environmental change on a global scale; the first four centuries of the last millennium were characterised by a sustained period of higher than average temperatures (known in the northern hemisphere as the Medieval Warm Period); this was followed by an interval of lower than average temperatures (the Little Ice Age), lasting until the mid-late 1800s.
The head of a fossilised oribatid mite (about 0.5 mm across). Mites are a potential new proxy for tracking pre-Incan economies in the Andes. Read more about this development here or listen here to a Today Programme interview on BBC Radio 4 (you will need Realplayer to listen to this file).
The factors driving the success and/or demise of the Incan forebears are not always clear, due in part to the fact that South American societies did not develop any form of written record. One school of thought holds that climatic variability may have played a major role in determining the success and/or failure of these cultures, particularly as the Andean environment is one in which successful agricultural practices require novel technological solutions (such as raised fields and terracing), even during optimal climatic circumstances, and are therefore highly susceptible to any decline in conditions. Another school of thought suggests that social and political pressures were dominant factors in the demise of pre-Incan Andean societies; and a third holds that it must have been a combination of socio-political and environmental factors which ultimately determined the success or failure of these cultures. Regardless of the merits underlying each of these arguments, it remains clear that the effects of environmental and socio-political changes on Andean cultures over the last two millennia remain poorly understood. Questions relating to population size, trading activities, land use, land degradation and large-scale demographic changes amongst these dominantly agricultural-pastoral societies continue to be largely unanswered or, at best, only inferred from a variety of often-incomplete palaeoenvironmental and archaeological records.
Research at Sussex concentrates on analysis of the palaeoenvironmental histories preserved in the sediments of the many lakes located in the Cuzco area of highland Peru. This region is not only sensitive to climatic variability, but has also been the centre of much of the societal development witnessed in the Andes over the past few thousand years. Work combines a rigorous palaeoenvironmental approach with an appreciation of the independently-derived archaeological record.
Current projects
Characterising the last 2000 years of climatic history in the Peruvian Andes. Collaboration with Alex Chepstow-Lusty (Sussex/IFEA), Brian Bauer (Chicago), Melanie Leng (NERC Isotope Geosciences Lab, Nottingham), Andy Cundy (Brighton) and Hubert Vonhof (Vreij Universiteit, Amsterdam) and Erick Gil (Universidad Nacional de San Antonio Abad del Cusco, Peru). Recent work by the group, published in Climate of the Past (see below), has formed part of a review by Jared Diamond in the journal Nature (vol. 461, 24 September 2009, pages 479-480) about societal resilience and response to environmental change.
Tracking the development of pre-Incan economies in the Andes using oribatid mite remains (funded by NERC). Collaboration with Alex Chepstow-Lusty (Sussex/IFEA), Anne Baker (Natural History Museum, London), Melanie Leng (NERC Isotope Geosciences Lab, Nottingham) and Alfredo Tupayachi Herrera (Universidad Nacional de San Antonio Abad del Cusco, Peru).
Publications
Chepstow-Lusty, A.J. (2011). Agro-pastoralism and social change in the Cuzco heartland of Peru: a brief history using environmental proxies. Antiquity 85, 570–582.
Frogley, M.R., Chepstow-Lusty, A.C. and Leng, M.J. (2010). High and dry in the Andes. Planet Earth (NERC magazine), Spring 2010 issue, 28-29.
Chepstow-Lusty, A.J., Frogley, M.R., Bauer, B.S., Leng, M.J., Boessenkool, K.P., Carcaillet, C., Ali, A.A. and Gioda, A. (2009). Putting the rise of the Inca Empire within a climatic and land management context. Climate of the Past 5, 375-388.
Chepstow-Lusty, A.C., Frogley, M.R., Bauer, B.S., Leng, M.J., Cundy, A.B., Boessenkool, K.P. & Gioda, A. (2007). Evaluating socio-economic change in the Andes using oribatid mite abundances as indicators of domestic animal densities. Journal of Archaeological Science 34 (7), 1178-1186.
Sterken, M., Sabbe, K., Chepstow-Lusty, A., Frogley, M.R., Cundy, A.B. & Vyverman, W. (2006). Climate and land use changes in the Cuzco region (Cordillera Oriental, South East Peru) during the last 1200 years: a diatom based reconstruction. Archiv für Hydrobiologie 165, 289-312.
Chepstow-Lusty, A.C., Bush, M.B., Frogley, M.R., Baker, P.A., Fritz, S.C. & Aronson, J. (2005). Vegetation and climate change on the Bolivian Altiplano between 108,000 and 18,000 yrs ago. Quaternary Research 63, 90-98.
Chepstow-Lusty, A., Bauer, B. & Frogley, M.R. (2004). The environmental history of the Cuzco region. In: Bauer, B. (ed.), Ancient Cuzco. University of Texas Press, Austin, pp. 23-29.
Chepstow-Lusty, A., Frogley, M.R., Bauer, B.S., Bush, M.B. & Herrera, A.T. (2003). A Late Holocene record of arid events from the Cuzco region, Peru. Journal of Quaternary Science 18 (6), 491-502.