Lichen studies along a wet sulfate deposition gradient in Pennsylvania

Lichens were surveyed at four study areas along a wet sulfate deposition gradient in north-central Pennsylvania. This study, performed in September 1988, utilized ten lichen study sites in each of the four study sites was conducted using 7.5' topographic maps in May 1988. Species richness was significantly less in high sulfate deposition areas than in low sulfate deposition areas. Although the causal agents for these differences are not known, it is hypothesized that SO2 is responsible at least in part