Document: BRY-3-83-10

Vegetation response to late-glacial and early Holocene climate change in New England.

SHUMAN, B.N.*, P.C.NEWBY and T.WEBB III

Brown University, Providence, RI 02912 USA ¹

Abstract:
Sedimentary evidence for climate change during the late-glacial and early Holocene in New England can be compared with fossil pollen records to examine the response of vegetation to climate change. Here, we use loss-on-ignition records from several small, closed kettle lakes to confirm climatic cooling in New England during the Younger Dryas chronozone (13,000 - 11,000 cal yr B.P.). Also, sedimentary evidence, provided from transects of cores, show that after the Younger Dryas chronozone, water-levels fell at many sites in New England. We interpret these data to mean that conditions became warmer and drier between 11,000 and 8,000 cal yr B.P., followed by relatively moist conditions by 7,000 cal yr B.P. The sedimentary record, therefore, documents a series of climatic changes: 1) cooling at 13,000 cal yr B.P., 2) warming and drying at 11,000 cal yr B.P., and 3) an increase in moisture availability after 8,000 cal yr B.P. The fossil pollen data illustrate vegetation responses to these climatic changes. The result is a climatic basis for the well-documented shifts, from Picea to Pinus, and then Quercus, in the dominant pollen types of the New England pollen zones. These climatic changes also likely influenced the arrival and expansion of Fagus, Tsuga, and other New England plant taxa, and impacted local ecosystems by, at least, changing the hydrology. By documenting the relationship between ecosystem dynamics and climate changes in New England between 14,000 and 7,000 cal yr B.P., we can provide a case study useful to conservation efforts ongoing in the face of future climate changes.

Keywords: Vegetation change, climate change, Holocene, late-glacial, lake-levels

This abstract is being presented at: 1:15 PM in session:
Oral Session #66: Large Scale Climate Change.