HR: 1340h
AN: U13B-1148    [Abstracts]
TI: Quantitative Estimates of Precipitation and Temperature Change and Associated Climate- Vegetation Feedbacks During Heinrich Events in Florida, USA
AU: * Donders, T H
EM: t.h.donders@uu.nl
AF: Palaeoecology, Institute of Environmental Biology, Laboratory of Palaeobotany and Palynology Budapestlaan 4, Utrecht, 3584 CD, Netherlands
AU: Dekker, S C
EM: s.dekker@geo.uu.nl
AF: Department of Environmental Sciences, Utrecht University, PO BOX 80115, Utrecht, 3508 TC, Netherlands
AU: Grimm, E C
EM: grimm@museum.state.il.us
AF: Illinois State Museum, 1011 East Ash Street, Springfield, IL 62703, United States
AU: Finsinger, W
EM: w.finsinger@uu.nl
AF: Palaeoecology, Institute of Environmental Biology, Laboratory of Palaeobotany and Palynology Budapestlaan 4, Utrecht, 3584 CD, Netherlands
AU: Wagner, F
EM: f.wagner@uu.nl
AF: Palaeoecology, Institute of Environmental Biology, Laboratory of Palaeobotany and Palynology Budapestlaan 4, Utrecht, 3584 CD, Netherlands
AB: Several paleoecological reconstructions from Lake Tulane in subtropical central Florida (USA) have revealed a series of sharp vegetation switches from open scrub oak and prairie communities towards pine dominated forests during the past 60 ky. A recently improved age model shows that the pine phases are coeval with North Atlantic stadials that are terminated by Heinrich events. Based on these vegetation reconstructions, the pine phases are now considered to represent warmer and wetter conditions in Florida, which points to an antiphase relationship between climate in Florida and the North Atlantic region. We have developed a number of pollen-climate inference models using surface sediment samples from the southeastern USA to quantitatively estimate the past climate changes associated with the vegetation shifts in Florida of the past 60 ky. The models are derived from partial least squares (PLS) and weighted-averaging PLS (WA-PLS) of summer and winter precipitation and growing-season temperature with bootstrap cross-validated prediction errors. Results show that summer rainfall increased by 80-90 mm/yr during Heinrich pine phases, while temperature increased between 0.5-1.0 degrees C. These reconstructions support the previous qualitative interpretations and permit testing with climate models. A regional vegetation-atmosphere model forced by the reconstructed climate shifts is used to investigate runoff and evaporation changes during Heinrich events and assess vegetation-climate feedback processes.
DE: 0545 Modeling (4255)
DE: 1632 Land cover change
DE: 1635 Oceans (1616, 3305, 4215, 4513)
DE: 1845 Limnology (0458, 4239, 4942)
DE: 1851 Plant ecology (0476)
SC: Union [U]
MN: 2007 Fall Meeting