Paleoecological history of west‐central okefenokee swamp based on palynologic and petrographic analysis

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Abstract
Palynologic and petrographic analyses were performed on nine cores selected from an east‐west transect in west central Okefe‐nokee Swamp. From these cores it was possible to reconstruct the local vegetational successions from the time of initial peat formation (about 6,000 yr B.P.) to the present and to draw some inferences about regional vegetational changes in southeastern Georgia. Both the pollen assemblages and petrographic data indicate a local upward change in vegetation from a marsh environment, consisting predominantly of Nymphaea, Gramineae and Cyper‐aceae (with Sagittaria and Xyris as moderate contributors), through a transitional zone dominated by Gramineae and Cyperaceae (with both Nymphaea and Taxodium as major contributors) and finally to a Taxodium‐dominated swamp‐forest (with Sphagnum and Woodwordia as moderate contributors). Sphagnum was noticeably absent in the lower zones, suggesting a change from a more minerotrophic setting at the base to a nutrient‐poor, ombrotrophic environment toward the top. Cheno‐podiaceae pollen exhibited the opposite trend (decrease toward the top). Regionally, an upward decease in Quercus and other hardwood trees was observed. This trend supports the findings of others (Watts, 1971; Rich, 1979; Fearn, 1981; Stack, 1985;) for a regional decrease in oak‐dominated forests in the southeastern United States.