Lichens and air quality in Chequamegon National Forest Rainbow Lake Wilderness Area: Final report

Abstract

This study of the lichens of Rainbow Lake Wilderness was designed 1) to collect lichens for a lichen species list, 2) to collect lichens for elemental analysis, 3) to study the health and distributions of species most sensitive to air pollution, and 4) to assess the effects of air quality on lichens. Twenty seven localities were studied throughout the wilderness. Samples of three species were collected at three localities and one species was collected at one locality for elemental analysis.

The lichen flora is quite diverse. There were 190 species present including seven species very sensitive to sulfur dioxide. The distributions of these sensitive species do not show patterns that would suggest directional air quality problems. All of the lichens found were in good health and with normal fertility. The lichens studied by elemental analysis show levels of all elements comparable to other clean areas. ANOVA and pairwise comparisons of the elemental data showed somewhat higher element levels at the northern edge of the RLW and no singificant differences between the Boundary Waters Canoe Area and RWL. Therefore , there seem to be no indications of air quality problems (mainly sulfur dioxide) in the wilderness.

Recommendations are for periodic (5 year) restudy of the lichens by elemental analysis. A complete lichen restudy of the lichen flora should be done every 10-15 years. If construction or maintenance activities are planned within the wilderness, a lichenologist should be consulted to prevent loss of species.