Pollen Analysis of Iola Bog and Paleoecology of the Two Creeks Forest Bed, Wisconsin

Abstract

Pollen analysis of Duck Creek Ridge, eastern Outagamie County, and Peter's Quarry, northeastern Brown County, two exposures of the Two Creeks Forest bed was completed to gain a more through understanding of the Two Creeks vegetation. Pollen and macrobotanical data reveal a simple flora dominated by boreal wetland pioneers Picea and Larix along with Cyperacea. Because of the high amounts of non—arboreal pollen, the general lack of stumps, roots, and logs associated with the deposit, and the field relations, the Two Creeks vegetation is believed to have been an open boreal woodland. Iola Bog, near the town of Iola in western Waupaca County, provided a late—glacial pollen record from outside the region of the Valders advance. The pollen record from Iola Bog was divided into nine zones that correlate well with the known glacial and climatic fluctuations, as well as with other work done in central Wisconsin. A basal Picea—Cyperaceae assemblage is replaced by a species—rich, mesic vegetation that represents the Two Creeks, interval. A drying trend is inferred to correlate with the Valders readvance; zones above this record the postglacial Pinus invasion and an Hypsithermal. A comparison of the Two Creeks localities and the Two Creeks core interval reveal marked differences in the inferred vegetation. This difference is explained by the shorter period the Two Creeks sites were exposed for revegetation and the pattern of invasion and colonization by boreal pioneer species.