Abnormal chemical element concentrations in lichens of Isle Royale National Park

Environmental and Experimental Botany



Lichens have been used for many years to monitor changes in deposited airborne chemical elements in many areas, but few studies have focused on areas suspected of experiencing slightly elevated pollution. Detection of subtle patterns of slightly elevated pollutants calls for developing several lines of evidence as opposed to single line studies used in heavily polluted areas. This study of two lichen species, Hypogymnia physodes and Evernia mesomorpha, in Isle Royale National Park, Michigan compares the concentrations and ranks of elements with the concentrations and ranks of the elements in the earth's crust, changes in element concentrations over a nine year period, and the geography of element concentrations in the park. S, Zn, Pb, Cd and Se were elevated in both species and higher in rank compared to the concentrations and ranks in the earth's crust. Toxic elements increased 123% in Hypogymnia and 62% in Evernia over 9 years, compared to increases of 45% and 59% for non-toxic elements in each species, respectively. Geographically, the lichens at certain localities with higher exposures experienced higher than average element concentrations. Finally, tissue concentrations of Mn, S and Se at some localities were above levels known to be either toxic or similar to those found in polluted areas. These four lines of evidence suggest that Isle Royale National Park is experiencing the onset of chronic air pollution stress from a number of sources.

Study Area

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Abnormal chemical element concentrations in lichens of Isle Royale National Park
Series title Environmental and Experimental Botany
Volume 35
Issue 3
Year Published 1995
Language English
Contributing office(s) National Wildlife Health Center
Description p. 259-277
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Environmental and Experimental Botany
First page 259
Last page 277
Country United States
State Michigan
Other Geospatial Isle Royale National Park
Online Only (Y/N) N
Additional Online Files (Y/N) N
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