Lichens as Bioindicators of Air Quality
Bennett, James P. .
23 Years of Lichen Elemental Analysis Studies in Great Lakes National Parks.
SINCE 1983, lichens have been sampled for elemental analyses in 13 national parks and other natural areas in four states in the Great Lakes region. Eleven species have been sampled at 166 localities as part of 37 park by year combinations. Concentration data on 29 elements, plus ash content, numbering over 35,000 data points will soon be available on the internet, as part of a larger database on lichen element data from national parks throughout the U. S. Analyses of the data have revealed patterns in space, time, by species, by thallus type, and by element. Notable among these is a significant 70% decline in Pb in the region during the period; and a small, but non-significant increase in S. Spatially, soil elements are higher in the Minnesota areas than in Wisconsin and Michigan, and Cu, Hg, Pb, S and Zn are higher in Michigan and Wisconsin than in Minnesota. This supports a hypothesis that soiling is upwind in the west, and pollutants are upwind in the east. All but one element were significantly higher in foliose species compared to fruticose species, with only Na being slightly higher in fruticose species. This appears to be due to the high affinities Hypogymnia physodes and Parmelia sulcata have for many elements, including Al, Ba, Ca, Cd, Co, Cu, Fe, K, Mg, Mn, Ni, P, Pb, S and Zn. Variation among species appears to be greater than variation geographically, suggesting that regional patterns are less important than species variability.
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1 - University of Wisconsin, Institute for Environmental Studies, 445 Henry Mall, Madison, Wisconsin, 53706, USA
Great Lakes region
Presentation Type: Symposium or Colloquium Presentation
Date: Tuesday, August 1st, 2006
Time: 10:45 AM