17 May 2011

Open University research on dung fungus sheds light on pre-Incan populations in Bolivia

New research from The Open University provides insight into levels of trade among pre-Incan populations in the Cochabamba Basin (Bolivia) and how environmental changes transformed their use of the landscape. The rise of the Tiwanaku culture and the later arrival of the Inca in Bolivia brought an increased use of the llama and alpaca in transporting goods and providing valuable resources. This major cultural change could be seen as the start of what is now viewed as the peak in prosperity of the first Andean civilisation, the Tiwanaku.

Published in Quaternary Research, the research links early human societies in the Andes, climate change and the environment. Joseph Williams, Research Student at the Palaeoenvironmental Change Research Group at The Open University and lead author, said: “The main Cochabamba Basin is today a major region for food production with topography that favours agriculture. We used a 4000 year record on vegetation, fire and cultural change to provide insight into climate change, pre-Columbian societies and the environment”.

The Cochabamba Basin is on the ancient road network connecting Andean and lowland areas. The eastern end of the Cochabamba valley system constricts at the Vacas Lake District, constraining the road network and providing an ideal location in which to examine past human–environmental interactions. An abundance of charcoal 2,000 – 4,000 years ago indicates continuous use of the ancient road network.

The research team analysed sediment from Lake Challacaba, which provided a reconstruction of its 4,000 year history. Fluctuations in the pollen of drought tolerant plant species and deposits of calcium carbonate indicate two periods of reduced moisture, compared to adjacent wetter episodes. The moisture fluctuations are associated with El Niño-Southern Oscillation variations, which are widely reported.

Today, the lakes within the Vacas municipality are an important source of water and feed for cattle which are driven into the lake during the dry season, and in the past were an important resource for the llama and alpaca herds. Herbivore presence around Lake Challacaba substantially increased from 1,210 years ago, as can be seen from pre-Columbian increases in dung deposition surrounding the lake. A decline in charcoal and an increase in dung fungus between 1,340 – 1,210 years ago suggest cultural changes were a major factor in shaping the modern landscape. The increase in the availability of dried dung allowed the local population to switch from predominately burning wood to using dung as more efficient fuel, as commonly used in rural areas of Bolivia today.

The research provides further insight into the lives of pre-Incan peoples, distant from the centres of the empire. Analysis of the deposited lake sediment builds on the limited existing knowledge from archaeological sites in this region, and helps to piece together how pre-Columbian peoples existed in a changing environment and how they impacted the local landscapes which they occupied.

Editor’s Notes
1. Authors J.J.Williams, W.D.Gosling and A.L.Coe are members of The Open University’s Centre for Earth, Planetary, Space & Astronomical Research (CEPSAR). The strength and excellence of the research supported by the Centre was acknowledged in the UK’s last Research Assessment Exercise (RAE 2008), with 70% of its research deemed internationally excellent and world-leading, achieving 3*/4* rankings. CEPSAR website:

Dr William Gosling supervised Joseph Williams’ research, and the National Geographic funded the field research.

2. The Open University is the UK’s largest university and a world leader in distance education, with more than 250,000 students in over 40 countries, over 1,300 of whom are postgraduate research students. The University celebrated its 40th anniversary in 2009.

3. Open Research Online (ORO), the University’s freely accessible repository of research publications, is available at: ORO has around 35,000 visitors from over 170 different countries each month, and is currently ranked the third best higher education repository in the UK by the Registry of Open Access Repositories (ROAR).

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