A HIGH-RESOLUTION LATE HOLOCENE POLLEN RECORD FROM AN OLD-GROWTH CYPRESS-TUPELO SWAMP, CYPRESS BRIDGE, VA

Cypress Bridge Swamp Nature Area Preserve is a Cypress-Tupelo swamp located along the Nottoway River in Virginia. The Preserve includes a 37-acre tract of un-cut, old growth forest that includes trees estimated to be between 800-1000 years old. From a 162cm sediment core collected in this virgin forested wetland, we used pollen biostratigraphy and carbon-14 dating to generate an age model spanning the last 1700 years. Here, we present paleohydrologic records with decadal to centennial-scale resolution, using pollen as a proxy to document the response of a forested wetland to late Holocene climate variability and post-Colonial land clearance on the Atlantic Coastal Plain, USA. Pollen assemblages generally are dominated by Pinus pollen, with Carya and Quercus subdominant, with fluctuations in abundance of hydrologic indicators recording variability in wetland hydroperiods. The most significant hydrologic shift occurred during the Little Ice Age (LIA; 450-150 cal yr BP), when consistent presence of Taxodium pollen indicates the presence of a cypress backswamp with long hydroperiods. The LIA is unconformably truncated by the agricultural horizon at ~ 200 cal yr BP, when Ambrosia pollen increased in abundance in response to Colonial land clearance. Abundant Nyssa pollen throughout the post-Colonial interval documents the persistence of backswamp vegetation with long hydroperiods during the last few centuries. Selective logging of hardwood species at different intervals during the post-Colonial era provides a record of land use but prevents interpretation of the post-Colonial vegetation response to regional climate variability.

Additional work on this core will allow us to further quantify the impact of regional climate variability on mid-Atlantic wetlands and provide resource managers with data on how these wetlands have responded to past periods of natural hydrologic variability.