Bryological and Lichenological Section/ABLS
Washburn, Stephen .
Impact of Ambient Air Pollutants on Lichen Flora in the Greater Cincinnati Area.
Ambient air quality in the U.S. has been steadily improving over the last four decades. However, there are still significant improvements to be made in the urban environment where ozone and nitrogen oxides predominate. Lichens are known to be excellent indicators of air quality, with respect to some air pollutants, particularly sulfur dioxide. The sensitivity of lichens as indicators of other air contaminants, such as ozone, has been uncertain. This study examined the potential impacts of air contaminants on lichens in the greater Cincinnati metropolitan area. Percent cover and species richness for individual lichen taxa was evaluated on 110 trees from 11 locations in the study area. The most common lichen in the urban environment was Physcia millegrana, and is found to be tolerant of urban air quality. Existing ozone concentration data were obtained from the U.S. EPA from 1999 to 2003 for 12 monitor stations. These data were analyzed to estimate cumulative "annual" ozone indices (e.g., SUM06 and W126). Concentrations of sulfur dioxide, nitrogen oxides, and ammonia were examined as covariates. A multivariate analysis was performed to detect any ecological impacts on community composition and species richness. We demonstrate that both NOx and ozone, as measured by the AOT40 and SUM00 ozone exposure indices, have a significant correlation with lichen abundance. Other ozone exposure indices including the U.S. EPA 1-Hour and 8-Hour National Ambient Air Quality Standards and the N100, SUM06, and W126 indices do not have a significant correlation with lichen abundance.
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1 - University of Cincinnati, Department of Biological Sciences, 614 Rieveschl Hall, Cincinnati, Ohio, 45221, USA
Presentation Type: Oral Paper
Date: Wednesday, August 17th, 2005
Time: 1:45 PM