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abstracts
Tropical cloud forest dendroclimatology and the demise of the Monteverde Golden Toad
Kevin Anchukaitis, Michael Evans
Recent, widespread amphibian extinctions in the mountains of the American tropics have been blamed on the interaction of anthropogenic climate change and a lethal pathogen. However, the temporal span of limited meteorological records make it impossible to confidently conclude whether current climate conditions at these sites are actually exceptional in the context of natural variability. Here, we use stable oxygen isotopes to reconstruct a century of hydrometeorological conditions in the Monteverde Cloud Forest of Costa Rica from trees without annual rings. Very high-resolution measurements reveal coherent isotope cycles that provide annual chronological control, which we confirm with precision radiocarbon assays. The amplitude of these cycles reflect interannual variability in dry season moisture. Dry years are associated with El Niño events and weaker tradewinds. Lower frequency oscillations appear to be related to multidecadal Pacific and Atlantic climate variability. There is no evidence of a trend in cloud forest hydroclimate associated with rising global mean temperatures. Rather, it appears that the extinction of the Monteverde Golden Toad (Bufo periglenes) occurred during an exceptionally dry interval caused by the 1986-7 El Niño event and coincident with a period of increased moisture seasonality.
Kevin Anchukaitis, Lamont Doherty Earth Observatory, Columbia University,61 Route 9W, Palisades, NY 10964, United States, kja@ldeo.columbia.edu
Michael Evans, University of Maryland, Department of Geology & ESSIC, College Park, MD 20742, United States
Session: CCT2: Proxy Development, Calibration and Validation
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