PARENT SESSION
Oral Session # 2: Paleoecology.
Presiding: B Lynch
Monday, August 4. 8:00 AM to 11:30 AM, SITCC Meeting Room 101.
The interpretability of wetland pollen records.
Finkelstein, Sarah*,1, Davis, Anthony1, 1 University of Toronto, Toronto, Ontario, Canada
ABSTRACT- The coastal wetlands of the Great Lakes region have been subject to heavy anthropogenic stresses over the past two centuries. Protecting and restoring these wetlands each require an understanding of natural rates and mechanisms of community change, including responses to shifts in climate and water level. Pollen analysis provides a useful method for studying the long-term dynamics of these systems. Essential to this analysis is the identification of sensitive plant species with interpretable pollen signatures. Using contemporary pollen rain studies, detailed morphological analysis of selected taxa, and the literature on species biology, we conclude that wetland pollen records can be useful in detailing long-term changes in wetlands. We emphasize here the representation in the pollen record of commonly dominant plants in Great Lakes coastal wetlands. Typha latifolia, T. angustifolia, T. x glauca and Sparganium eurycarpum can be separated in the pollen record on the basis of morphology. These have different sensitivities to water depth and different impacts on wetland communities. Typha pollen production, however, can be low relative to the abundance of plants; pollen percentages as low as 7% can indicate monodominant Typha stands. Zizania aquatica can be distinguished palynologically from other stand-forming grasses on the bases of size and exine sculpturing. Its pollen production is large relative to its plant abundance. Although Phragmites pollen is distinctive, the habitat range of this species is broad enough that its value as a paleoecological indicator is ambiguous.
Key words: pollen, Zizania, wetland paleoecology, Typha