Modern and ancient pollen sedimentation around tree islands in the Okefenokee Swamp

Abstract

Peat cores taken from Okefenokee Swamp tree‐islands ("houses") and analyzed by peat petrography and pollen stratigraphy permit us to reconstruct the plant successions which led to the “house”; formation. The peats are believed to be autochthonous and their petrology has been shown to provide an accurate record of plant successions in cores. Because of differences among pollen grain transportation and sedimentation, the reliability of pollen profiles from the islands was initially questioned. The profiles may not represent an accurate record of “house”; vegetational history. Analysis of pollen assemblages collected in the marsh area around an island indicates two distinct assemblages: one derived from shrubs found on the island (Ilex, Cyrilla, Ericaceae); another derived from the surrounding marsh, consisting of aquatic herbs and arboreal genera (Nymphaea, Pinus, Myrica). Palynological analysis of island peats show that shrub pollen is deposited primarily on the island with little contamination from the aquatic herb pollen of the marsh. This indicates the reliability of these data for vegetational history reconstruction. Where the “house”; assemblage occurs above or below a marsh assemblage in core profiles, we observed an actual change of successional communities.