Re-evaluation of Pollen-Climate Transfer Functions in Keewatin, Northern Canada.

Multivariate statistical analyses allow specification of pollen-climate transfer functions useful in studies of paleoclimate. Two previously published models, when applied to two documented sites in Canada's District of Keewatin, produce inconsistent reconstructions of mean July temperatures for themed- to late-Holocene (approximately the past 5,000 years). The discrepancy between the results arises from differences in the construction of the functions. Of particular importance are the choice of pollen taxa included, and the sample provenances and the geographical range of the modern pollen data. A new model is developed with all-possible subsets regression, with due regard to the assumptions of the general linear model. Linear relationships between taxa abundances and summer temperature are specified, and multivariate outliers are removed. The paleotemperature records produced by the model for the two sites are consistent with the general features of previously reported work, and are more nearly similar to each other than reconstructions produced by the earlier, less sophisticated, models. [ABSTRACT FROM AUTHOR]