Local impacts of a rural coal-burning generating station on lichen abundance in a New England forest

To test whether emissions from a coal-burning, electrical generating statio n in rural Massachusetts have had measurable ecological impacts on the surr ounding riparian forest, we compared abundance of epiphytic lichens at diff erent distances from the station. Per cent covers of crustose, fruticose, a nd foliose lichens were measured along l-km transects downwind and upwind f rom the station on the north and south sides of trunks of two dominant tree species, Acer saccharinum and Populus deltoides. Lichen cover increased wi th distance from the station, especially in the upwind direction. The tende ncy for lichens to be more abundant on the north than on the south side of trees also increased with distance from the station. These effects of dista nce and side on lichen abundance were stronger in some lichen growth forms than in others and also depended on host tree species. Two different method s of measuring lichen cover, visual estimate and point occurrence, gave sim ilar values. We conclude that emissions from the station have had measurabl e impacts on the adjoining plant community. (C) 1999 Elsevier Science Ltd. All rights reserved.