Rock Gnome Lichen (Gymnoderma lineare) Monitoring Assessment, Southern Appalachian Mountains, 1983–2008

Open-File Report 2021-1011
Prepared in cooperation with the U.S. Fish and Wildlife Service



Rock gnome lichen (Gymnoderma lineare [Evans] Yoshimura and Sharp) was listed as a federally endangered species in 1995. It is endemic to the southern Appalachian Mountains, with most known populations occurring in North Carolina, where it grows on vertical rock faces in the fog zone above an elevation of 1,525 meters or in humid, deep river gorges. Threats to the species include recreational use of habitat by hikers, climbers and sightseers; collectors; changes in microclimate due to loss of Fraser fir (Abies fraseri) to the exotic pest balsam woolly adelgid (Adelges piceae); air pollution; and climate change. Quantified estimates of population size are limited in number and only are available from 1983 to 2008. They show that known rock gnome populations increased in number during this period and increased in size from 1996 to 2008. The period of increase coincided with negative trends in nitrogen and sulfur deposition, stable precipitation and streamflow, and a positive trend in air temperature. Populations may have been afforded greater protection from recreational activities and collectors during this time. Specific incidents of population decline were associated with a high streamflow event and loss of shade owing to a fallen Fraser fir. Although the outlook for rock gnome lichen seems to have improved through 2008, threats from climate change and increasing human activity likely are increasing.

Suggested Citation

Woodward, A., 2021, Rock gnome lichen (Gymnoderma lineare) monitoring assessment, southern Appalachian Mountains, 1983–2008: U.S. Geological Survey Open-File Report 2021–1011, 12 p.,

ISSN: 2331-1258 (online)

Study Area

Table of Contents

  • Abstract
  • Background
  • Objectives
  • Methods
  • Results of Updated Analysis of Rock Gnome Populations
  • Discussion
  • Conclusions
  • Acknowledgments
  • References Cited
Publication type Report
Publication Subtype USGS Numbered Series
Title Rock gnome lichen (Gymnoderma lineare) monitoring assessment, southern Appalachian Mountains, 1983–2008
Series title Open-File Report
Series number 2021-1011
DOI 10.3133/ofr20211011
Year Published 2021
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Forest and Rangeland Ecosystem Science Center
Description v, 12 p.
Country United States
State North Carolina
Other Geospatial Southern Appalachian Mountains
Online Only (Y/N) Y
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Additional publication details