Chemical element concentrations in four lichens on a transect entering Voyageurs National Park

Environmental and Experimental Botany
By:  and 



A three factor transect study was conducted to test the hypothesis that chemical elements from air emissions in the vicinity of International Falls, Minnesota could not be detected in lichens along a 24 km transect reaching into Voyageurs National Park. It was hypothesized that element concentrations in lichens would decline exponentially downwind and would reach background values at a distance before the park boundary. Four species (Cladina rangiferina, Evernia mesomorpha, Hypogymnia physodes, and Parmelia sulcata) were sampled at ten sites for 3 years and 17 chemical elements were measured. The most notable result was a curvilinear geographic trend for many elements, which decreased from International Falls and then increased towards the park. This trend was significant for many anthropogenic elements, including S, Hg, Cd, and Cr, and for all four species. This type of distribution pattern has been observed in Hypogymnia physodes in other studies downwind of a steel mill and an oil refinery. Cladina, a ground-dwelling lichen, generally had lower tissue concentrations of the elements than the three epiphytic species. Tissue concentrations over the 3 years of sampling declined an average of 12%. Sufficient evidence exists to conclude that lichen tissue element concentrations in the vicinity of International Falls may be related to local air emissions, and that an exponential decline of element concentrations downwind of the sources does not apply to this situation.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Chemical element concentrations in four lichens on a transect entering Voyageurs National Park
Series title Environmental and Experimental Botany
DOI 10.1016/S0098-8472(96)01039-8
Volume 37
Issue 2-3
Year Published 1997
Language English
Publisher Elsevier
Contributing office(s) National Wildlife Health Center
Description 13 p.
First page 173
Last page 185
Country United States
State Minnesota
City International Falls
Other Geospatial Voyaguers National Park
Online Only (Y/N) N
Additional Online Files (Y/N) N
Google Analytic Metrics Metrics page
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