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The Response of Vegetation on the Andean Flank in Western Amazonia to Pleistocene Climate Change

Cárdenas, Macarena L., Gosling, William D., Sherlock, Sarah C., Poole, Imogen, Pennington, R. Toby, Mothes, Patricia
Science 2011 v.331 no.6020 pp. 1055-1058
Podocarpus, biodiversity, climate, climate change, cooling, fossils, isotopes, montane forests, plant communities, pollen, radiometry, temperature, volcanic ash, wood, Amazonia, Andes region, Ecuador
A reconstruction of past environmental change from Ecuador reveals the response of lower montane forest on the Andean flank in western Amazonia to glacial-interglacial global climate change. Radiometric dating of volcanic ash indicates that deposition occurred approximately 324,000 to 193,000 years ago during parts of Marine Isotope Stages 9, 7, and 6. Fossil pollen and wood preserved within organic sediments suggest that the composition of the forest altered radically in response to glacial-interglacial climate change. The presence of Podocarpus macrofossils approximately 1000 meters below the lower limit of their modern distribution indicates a relative cooling of at least 5°C during glacials and persistence of wet conditions. Interglacial deposits contain thermophilic palms suggesting warm and wet climates. Hence, global temperature change can radically alter vegetation communities and biodiversity in this region.