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Phaeophyscia leana (Tuck.) Essl.

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Scientific name
Phaeophyscia leana
(Tuck.) Essl.
Common names
IUCN Specialist Group
Assessment status
Assessment date
IUCN Red List Category
IUCN Red List Criteria
Lendemer, J.
Scheidegger, C. & McMullin, T.

Assessment Notes

The content on this page is fetched from The IUCN Red List of Threatened Species: https://www.iucnredlist.org/species/80703017/80703024


Phaeophyscia leana is a conspicuous macrolichen that occurs on the bark of trees above the high water line in periodically inundated floodplain forests along the Ohio River, associated waterways, and associated wetlands in central North America. The primary pressures on this species are from habitat loss or degradation, alteration of hydrological regimes, and pollution. Formal ranking and protections for the species, long-term monitoring of populations, improved conservation, and restoration of suitable habitat are actions that would improve the status of the species. The species has a limited Area of Occupancy (minimum AOO = 184 km2), severe fragmentation of the population, and ongoing declines in AOO, Extent of Occurrence and habitat quality. Therefore, it is listed as Endangered under criterion B2ab(i,ii,iii,v).

Geographic range

Phaeophyscia leana is narrowly endemic to areas associated with the Ohio River and its associated waterways (e.g. Cumberland River, Green River, Tennessee River, Wabash River, White River) in Alabama, Illinois, Indiana, Kentucky, Ohio and Tennessee in the United States of America.

Population and Trends

The population of Phaeophyscia leana is located on protected land as well as private land, and many known sites are in parks adjacent to urban or suburban areas.

Population Trend: decreasing

Habitat and Ecology

Phaeophyscia leana occurs on the bark of primarily hardwood trees in floodplain forests and swamps or riparian areas associated with ox-bow lakes and sloughs. The species has a narrow ecology in that it occurs at a specific height on the trunks of trees, just above the high-water mark of frequent inundation, within the floodplain and where there is little competition from other lichens.


There are five primary pressures on this species. The first stems from the large-scale loss and degradation of suitable habitat throughout its range, including development of river frontage, large scale conversion of habitat for agriculture, barge/ship traffic on the Ohio River, and development of understorey vegetation in habitats where such vegetation would not be present. The second stems from a lack of uniform protection for the species at the federal level, and across state boundaries within its range. The third is the potential impacts of air and water pollutants on the lichen itself and the ecosystems in which it occurs. The fourth is that the unique ecology of the species means that it could be impacted by alterations to hydrological regimes, as well as both intense flooding or droughts. Finally, an important host tree for the species, ash (Fraxinus), is currently undergoing large-scale mortality due to an invasive pest, leading to loss of suitable habitat for the species and morality of extant individuals. 

Conservation Actions

The species has the following state ranks: Illinois: Threatened (Illinois Endangered Species Protection Board 2015); Kentucky: Endangered (Kentucky State Nature Preserves Commission 2010); Ohio: Endangered (Ohio Department of Natural Resources 2014). It was also petitioned for Endangered Species Act listing in 2010, with a subsequent 90-day “Substantial” finding (U.S. Department of the Interior 2011), however a decision as to its status has not been reached. In addition to formal listing as an endangered species, conservation of the species would be effected by enhancing protected status of the existing locations, and continuing monitoring efforts of populations. Further research and monitoring of the species may also be beneficial.

Source and Citation

Lendemer, J. 2020. Phaeophyscia leana. The IUCN Red List of Threatened Species 2020: e.T80703017A80703024. https://dx.doi.org/10.2305/IUCN.UK.2020-3.RLTS.T80703017A80703024.en .Downloaded on 31 January 2021

Country occurrence