PETERSON, ERIC B.1* and PETER NEITLICH2. 1Nevada Natural Heritage Program, 1550 E. College Pkwy #145, Carson City, NV, 89706; 2White Mountain Research Station, 3000 E. Line St., Bishop, CA, 93514. - Lichen communities, pollution signals, and an issue of scale.
The Forest Health Monitoring project is a nationwide effort by the US
to monitor several aspects of forest health. Lichen communities are
included in the monitoring, mainly due to concerns over pollution. In
Colorado, lichens were sampled through most of the 1990's leading to a
statewide pollution gradient model. In developing the statewide model,
a few places of particular concern were noted, including the Yampa
Valley and Park Range. This area is downwind of two large coal-fired
power plants that annually emit an estimated 20,000 metric tons of
sulfur dioxide and 25,000 tons of nitrogen oxides. During the summer
of 2000 we added 33 plots to the Park Range and an additional 2 plots
to the Elkhead and Flat Top Ranges which flank the power plants. Our
additional sampling was intended to (1) document lichen communities
after 30 years of emissions, and (2) establish a baseline for
following long term changes in lichen communities relative to changes
in air quality. When we began analyzing the data, we had difficulty
correlating the distance from the nearest power plant with the
pollution index calculated from the statewide model. That model was
based on the relative presence of pollution tolerant species. Many of
these occur primarily on Populus tremuloides. We suspect that
Populus tremuloides stands in the Park Range are naturally good
habitats for these species independent of any pollution presence. What
we did find correlating with distance from the nearest power plant was
the absence of pollution tolerant species. These would be difficult to
use in a statewide pollution gradient model because few lichen species
occur in all forested areas of the state.
Key words: community analysis, landscape, lichen, local scale, pollution