Glacial-interglacial climate cycles are known to have triggered migrations and reassortments of tropical biota. Although long-term precessionally-driven changes in temperature and precipitation have been demonstrated using tropical sediment records, responses to abrupt climate changes, e.g. the cooling of Heinrich stadials or warmings of the deglaciation, are poorly documented. The best predictions of future forest responses to ongoing warming will rely on evaluating the influences of both abrupt and long-term climate changes on past ecosystems. A sedimentary sequence recovered from Lake Petén-Itzá, Guatemalan lowlands, provided a natural archive of environmental history. Pollen and charcoal analyses were used to reconstruct the vegetation and climate history of the area during the last 86,000 years. We found that vegetation composition and air temperature were strongly influenced by millennial-scale changes in the North Atlantic Ocean. Whereas Greenland warm interstadials were associated with warm and relatively wet conditions in the Central American lowlands, cold Greenland stadials, especially those associated with Heinrich events, caused extremely dry and cold conditions. Even though the vegetation seemed to have been highly resilient, plant associations without modern analogs emerged mostly following sharp climate pulses of either warmth or cold, and were paralleled by exceptionally high rates of ecological change. Although pulses of temperature change are evident in this 86,000-year record none matched the rates projected for the 21st Century. According to our findings, the ongoing rapid warming will cause no-modern-analog communities, which given the improbability of returning to lower-than-modern CO 2 levels, anthropogenic barriers to migration, and increased anthropogenic fires, will pose immense threats to the biodiversity of the region.
Bibliographical noteFunding Information:
We are grateful to H. Hooghiemstra, an anonymous reviewer, and J.S. Carrión, handling editor, whose comments strengthened the manuscript. We thank all individuals who participated in the field and laboratory work during the Lake Petén-Itzá Scientific Drilling Project. We are also grateful to the numerous agencies and individuals in Guatemala who provided assistance to the project. We also thank our many collaborators from University of Florida, University of Minnesota (Minneapolis/Duluth), Geoforschungszentrum (Potsdam), Swiss Federal Institute of Technology (Zurich), Université de Genève, as well as the personnel of DOSECC. The cores are archived at LacCore (National Lacustrine Core Repository), Department of Geology and Geophysics, University of Minnesota-Twin Cities and we thank Kristina Brady, Amy Myrbo and Anders Noren for their assistance in core description and curation. Anders Noren kindly sampled the cores for this study. This project was funded by grants from the US National Science Foundation ( ATM-0502030 ), the International Continental Scientific Drilling Program , the Swiss Federal Institute of Technology , and the Swiss National Science Foundation . This is publication 66 of the Florida Institute of Technology Institute for Research on Global Climate Change.
Copyright 2012 Elsevier B.V., All rights reserved.
- Central America
- Climate change
- Ecological change
- Heinrich stadials
- Last Glacial Maximum
Continental Scientific Drilling Facility tags