Calibration of pollen assemblages and carbon–nitrogen ratios to discriminate boreal wetland types

Abstract

Differentiation of boreal wetlands in the palaeo record is required for studies of isostacy and sea level change, landscape change, and climate dynamics. To develop palynomorph signatures and calibrate soil C–N ratios for boreal wetlands we sampled low and high elevation tidal marshes, fens and bogs along eastern James Bay, Canada. A discriminant analysis model showed that a small subset of palynomorph taxa can effectively discriminate between the four wetland types. Cyperaceae, Poaceae, and Potamogeton–Triglochin-type are important to the classification of high marshes. Bryidae spores and pollen of Myrica gale, Cyperaceae, and Poaceae are indicative of fen. Moss spores alone, primarily from Sphagnum, but also Bryidae type spores, derived from brown mosses are the indicators of bog. The use of palynomorph assemblages to discriminate among wetland types is not dependent upon the localized presence of a plant source — as it would be using macrofossil analysis. C/N of bog soils can be clearly distinguished from fen and tidal marshes and can be used as a pollen-independent proxy to indicate fen to bog wetland succession.