• 1Proposed
  • 2Under Assessment
  • 3Preliminary Assessed
  • 4Assessed
  • 5Published

Arthonia kermesina R.C. Harris, E. Tripp, & Lendemer

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Scientific name
Arthonia kermesina
R.C. Harris, E. Tripp, & Lendemer
Common names
hot dots
IUCN Specialist Group
Assessment status
Proposed by
Erin Tripp
Toby Spribille
James Lendemer, Thomas Læssøe, Toby Spribille, Erin Tripp
Comments etc.
Anders Dahlberg, Christoph Scheidegger

Assessment Notes

Taxonomic notes

Why suggested for a Global Red List Assessment?

Arthonia kermesina (Hot Dots) is a highly charismatic microlichen that is endemic to high elevation spruce-fir forests of the southern Appalachians. It’s restricted distribution and narrow affinity to old growth montane forests suggest that this species should be high on lists of consideration for conservation activities in North America.

EOO calculated at 1209 km2, but this includes unsuitable lowland habitat between Smokies and Black Mtns.

AOO is calculated by Geocat at 48 km2.

The first specimen of the species was collected in 1965 (prior to its description). There are no documented outright extirpations.

Criterion A: historic decline due to logging; Maxent models of habitat decline plus disappearance of substrate trees due to introduced pathogens and pollution-associated forest dieback (J. Allen, pers. comm.) predict that suitable habitat will completely disappear within 75-100 yr. The species thus scores CR under A2(c,e,), A3(c,e) and A4(c,e).
Criterion B: currently 10 populations are known for this species based on clustering of quadrat adjacency in Geocat. Applies for VU if 95-100% sampling completeness is accepted in combination with inferred decline in AOO and area, extent and quality of habitat within last three generations (est. 90 years according to 2014 guidelines.
Criterion C does not apply.
Criterion D does not apply.
Criterion E does not apply.

Conclusion: species is proposed for CR A2(c,e), A3(c,e), A4(c,e) pending J. Allen modeling publication and/or other documentation of modeled habitat decline.

Geographic range

Hot Dots is restricted to the southern Appalachian Mountains of eastern North America. It is known only from Great Smoky Mountains National Park, with a single occurrence outside the Park, in suitable habitat of the nearby Black Mountains of North Carolina.

Population and Trends

Population Trend: Uncertain

Habitat and Ecology

Hot Dots is restricted to the bark of very mature trees of Picea rubens (Red Spruce), at upper elevations in the southern Appalachians. Since discovering this species several years ago, the original authors have searched for it extensively but have failed to find it in any other type of habitat.


Primary threats to Hot Dots include fog pollution, air pollution, forest degradation from invasive organisms, and global climate change. Because suitable habitat for this species is rare in the southern Mountains, and because the closest extensive suitable habitat is hundreds to thousands of miles away (to the north), Hot Dots may be particularly at risk to warming temperatures.

Tourism & recreation areasTransportation & service corridorsRoads & railroadsUtility & service linesNatural system modificationsInvasive & other problematic species, genes & diseasesInvasive non-native/alien species/diseasesNamed speciesPollutionAir-borne pollutantsAcid rainClimate change & severe weatherHabitat shifting & alterationDroughtsTemperature extremesOther impacts

Conservation Actions

There are currently no focused conservation activities to protect this species.

Site/area managementInvasive/problematic species controlHabitat & natural process restorationSpecies recoveryEducation & awarenessFormal educationAwareness & communicationsLaw & policyLegislationNational level

Research needed

Because Hot Dots is so conspicuous on the bark of mature trees, amateur and / or professional lichenologists could readily search for more populations of this species in areas beyond Great Smoky Mountains National Park.

Population size, distribution & trendsLife history & ecologyThreatsActionsConservation PlanningSpecies Action/Recovery PlanArea-based Management PlanMonitoringPopulation trendsHabitat trends

Use and Trade


Lendemer, J.C., R.C. Harris, and E.A. Tripp. 2013. The Lichens and Allied Fungi of Great Smoky Mountains National Park. The New York Botanical Garden Press, 260 pp.

Known distribution - countries

Regional Population and Trends

Country Trend Redlisted