Degree Name

Master of Science (MS)

Semester of Degree Completion


Thesis Director

Andrew S. Methven


In 1971, a graduate student at Eastern Illinois University, James E. Wiedman, studied the lichen flora of Rocky Branch Nature Preserve, Clark County, Illinois. During his study he collected, identified, and recorded a total of 64 lichen species. Since 1971, Rocky Branch Nature Preserve has experienced a dramatic increase in use by people and a concomittant decline in the quality of lichen habitats. In order to assess the decline of suitable lichen habitats and the reduction of lichen species a second study of the lichens at Rocky Branch Nature Preserve was undertaken. As part of this study, ten habitat sites were selected from which lichens were collected, identified, and recorded. Ten collecting trips were made and a total of 46 lichen species were collected. A comparison of lichens collected in 1971 and 1993 is included as are all possible explanations for the decline in lichen diversity over this twenty-two year period.