PARENT SESSION
Poster Session 21: Paleoecology
Wednesday, August 10, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Pollen Signatures of Everglades Tree Island Vegetation Zones.
Byers, Stacey*,1, McEnroe, Nicola1, Sabourin, Anne1, Ross, Michael2, Stone, Peter3, Chmura, Gail1, 1 McGill University, Montreal, Quebec, Canada2 Florida International University, Miami, Florida3 South Carolina Department of Health and Environmental Control, Columbia, South Carolina
ABSTRACT- Everglades tree islands are distinct patches of arboreal vegetation surrounded by herbaceaous wetland communities, often dominated by sawgrass (Cladium jamaicense). The larger tree islands (< 2 km long) are tapered with their long axis oriented parallel to the direction of water flow. Elevation declines from the upstream head of the island, providing a gradient in hydroperiod and subsequently vegetation composition. Four distinct communities are recognized. The Hardwood Hammock occupying the highest elevation, is rarely inundated. At a lower elevation is Bayhead forest which floods during most wet seasons. As elevation further declines and flooding becomes more prolonged, the forest canopy opens, and the herb layer increases in cover and diversity in the Bayhead Swamp. Eventually trees become scattered and give way to the tall sawgrass of the Tail community. Extensive modifications to the Everglades hydrology have probably affected the extent and nature of tree island communities, but paleoecological studies are needed to document that response. Palynological signatures have been successfully developed to distinguish between broad-scale Everglades ecosystems, such as tree islands or permanently flooded sloughs. In our study we search for indicators to distinguish among the communities within a tree island and interpret historical tree island vegetation change. The palynological signatures are derived from surface soils collected in each of the four tree island communities and are compared to pollen stratigraphies developed from sediment cores collected from three different tree islands of Everglades National Park.
Key words: Shark River Slough, Everlades National Park, modern pollen analogs, historical ecology