Late Pleistocene and Holocene Vegetation Changes in the Sandhills, Fort Jackson, South Carolina

Document Type

Article

Publication Date

10-2011

Publication Title

Southeastern Geology

Abstract

A small streamhead pocosin wetland at Fort Jackson, South Carolina, preserves a history of late Pleistocene and Holocene plant communities in an upland habitat of the Sandhills of the upper Coastal Plain. During the late Pleistocene, the assemblage of Pinus (pine, including P. banksiana [jack pine]), Picea(spruce), and Asteroideae (a sub-family of Asteraceae, the sunflower family) signals a cold, dry climate.Quercus (oak) was sparse; Liquidambar (sweetgum) and Nyssa (tupelo) were absent. During the Holocene, pine dominated except for an interval of oak dominance beginning after 9,520 cal yr BP and ending around 7,400 cal yr BP. Sediment characteristics suggest higher or more intense precipitation in the earlier segments of the Holocene record. Evidence from the pollen record is equivocal. Higher proportions of Nyssa(probably N. biflora, an obligate wetland species, or N. sylvatica, a facultative wetland species, or both) during the oak interval dominance could indicate expansion of the wetland, reduced fire frequency, or decreased pollen contributions from other sources, such as pine in the uplands. The rapid transition back to pine dominance was accompanied by decreases in Nyssa and Fagus (beech, prominent only in the uppermost sample of the mid-Holocene oak interval) and an increase in Gramineae (grasses), suggesting an increase in fire frequency or intensity, a decrease in moisture, or both. Asynchronies in the oak-pine transition across the Coastal Plain suggest that it is a poor proxy for Holocene climate change. The asynchronies may be in part a consequence of the importance of fire in shaping these communities.

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