Dr. Jonathan Dey works primarily on fruticose and foliose macrolichens in the eastern and southeastern regions--although he has field experience in many regions of the continental United States and Hawaii. Collaborations with IWU students have included field and laboratory studies of macrolichens in the Monongahela National Forest Region of West Virginia, in the Land Between the Lakes National Recreation Area in Tennessee and Kentucky, in the Great Smoky Mountains National Park in Tennessee and North Carolina, and in Mammoth Cave National Park, Kentucky. Other students have worked on various herbarium specimen based lichenological projects.

Dr. Dey's current work centers on contributing to the macrolichen inventory of the Great Smoky Mountains National Park as part of the All Taxa Biodiversity Inventory (ATBI) of the Park. IWU student research assistants (Rebecca Rincker and Holly Grey in 1998; Jana Rose and Adrianne Gagnon in 2000; Emily Richter and Sarah Mick in 2003; Erin Boente in 2004-5) have helped both with field work and identifications of specimens.

During the 1990s, Dey was a member of a scientific team, with Dr. Bruce McCune of Oregon State University and Dr. Susan Will-Wolf of the University of Wisconsin-Madison, developing and applying a lichen community indicator model used in monitoring the air quality in forest ecosystems in the middle Atlantic and southeastern United States as part of the National Forest Health Monitoring Program (now, in part, called the Forest Inventory and Analysis program).