Date of Award

2014

Document Type

Thesis

Degree Name

Master of Environmental Studies (MES)

First Advisor

Robert Reber

Second Advisor

Paul Rothrock

Third Advisor

Ray Showman

Abstract

The hardwood forests of Indiana are experiencing a decline in oak (Quercus) regeneration. Most forests are undergoing sugar maple (Acer saccharum) replacement in the understory. This dynamic is of concern because of the potential decline in total species diversity in these forests. Lichens can be valuable indicators of forest health; however, they are not included in Indiana’s forest health monitoring program. An analysis of lichen biodiversity was conducted at Salamonie River State Forest (SRSF) in Wabash County, Indiana. The objectives of this study were to survey the current lichen biodiversity within SRSF in northeastern Indiana and to evaluate a potential shift in lichen diversity due to the maple growth in forests with an oak dominant canopy. Additional questions related to the dependence of lichen richness and coverage on bark crevice depth, tree diameter, and a soil moisture gradient were addressed.

A total of 11 species of corticolous macrolichens were identified in the study. The shade tolerant lichen, Phaeophyscia rubropulchra, was found in the highest abundance in each plot and on sugar maples. There is the potential for P. rubropulchra to outcompete other lichen species. Mean lichen richness and coverage were significantly higher in upland sites. A general regression analysis revealed as the mean bark crevice depth increased, the mean lichen coverage decreased. Tree diameter was not a statistically significant variable. An R² value of 15.5% indicated that more factors were at work determining lichen coverage and diversity than those included in this study. Overcrowding in the understory by sugar maples reduces the light intensity which may explain the decline in lichen diversity and coverage on the trunks of oak species. Silvicultural treatments such as the thinning of sugar maples and the opening of gaps in the forest canopy could help increase the biodiversity of lichens in the forest and promote overall forest health.

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