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abstracts
Seven centuries of precipitation variations in the Bolivian Altiplano inferred from the world’s highest-elevation tree-ring records: Environmental and sociocultural implications
Mariano Morales, Axel Nielsen, Ricardo Villalba, Jeanette Pacajes, Jaime Argollo, Duncan Christie
Dry farming and pastoral economies in the Bolivian Altiplano are sensitive to fluctuations in climate, particularly drought. However, it is difficult to examine these relationships because of the scarcity, shortness and inhomogeneity of the available instrumental climate records. The recent development of well-replicated, climate-sensitive tree-ring records from Polylepis tarapacana allows the reconstruction of past environmental conditions at various temporal scales and examination of the links between climate and particular events in past human history. Polylepis tarapacana, growing between ca 4500-5000m, has remarkable dendrochronological potential, and was regularly used by pre-Columbian populations for fuel and construction. We used a network of P. tarapacana chronologies to reconstruct precipitation variability in the Bolivian Altiplano for the past 640 years. This reconstruction has periods of several decades with precipitation below the mean and a negative trend in precipitation during the last 150 years. Archeologists have identified a major shift in settlement patterns in the Altiplano-Puna and adjacent valleys during the 14th and 15th centuries. Low-elevation, vulnerable villages occupied until the 13th century were rapidly abandoned in favor of highly visible, frequently fortified sites with difficult access. This process has traditionally been related to the onset of a state of endemic warfare, possibly triggered by periods of drought resulting in repeated crop failure and high animal mortality that forced dry farmers and pastoralists to fight for the control of marshes and irrigable farmlands on both sides of the Andes. The reconstruction of severe drought in AD 1380-1399 and 1432-1452 provide strong support for this hypothesis.
Mariano Morales, IANIGLA, CONICET,Av. Ruiz Leal s/n, CC: 330, Mendoza, 5500, Argentina, mmorales@lab.cricyt.edu.ar
Axel Nielsen, Universidad de Buenos Aires, Instituto Interdisciplinario Tilcara , Argentina
Ricardo Villalba, CONICET, IANIGLA, 5500, Argentina
Jeanette Pacajes, Universidad Mayor de San Andrés, Laboratory of Dendrochronology, Bolivia
Jaime Argollo, Universidad Mayor de San Andrés, Laboratory of Dendrochronology, Bolivia
Duncan Christie, Universidad Austral de Chile, Laboratory of Dendrochronology, Chile
Session: F4: Human-Climate-Ecosystem Interactions
Download Talk:
> YSM09_OralG_Morales.pdf
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