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Sulcaria spiralifera (Brodo & D. Hawksw.) Myllys, Velmala & Goward

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Scientific name
Sulcaria spiralifera
(Brodo & D. Hawksw.) Myllys, Velmala & Goward
Common names
IUCN Specialist Group
Assessment status
Assessment date
IUCN Red List Category
IUCN Red List Criteria
B2ab(i,ii,iii,iv,v); C2a(i)
McMullin, T., Stone, D., Lendemer, J. & Allen, J.
Reese Næsborg, R.

Assessment Notes

The content on this page is fetched from The IUCN Red List of Threatened Species: https://www.iucnredlist.org/species/80703106/80703113


Sulcaria spiralifera is a fruticose arboreal lichen that is endemic to coastal dune forests in western North America. It occurs at scattered localities from central California to Washington. It is rare throughout its range, except on the Samoa Peninsula in California's Humboldt County and on the Oregon Dunes in Coos County where it is locally abundant (Glavich 2003, 2008). This species, and its rare and sensitive ecosystem, are threatened by coastal development, climate change, and air pollution. This species is severely fragmented with an area of occupancy of only 104 km2, and is therefore Endangered under criterion B2. Its small and fragmented population containing fewer than 2,500 mature individuals also qualifies it as Endangered under criterion C2a(i)

Geographic range

Sulcaria spiralifera occurs at scattered and isolated localities from central California to Washington, but it is locally common only on the Samoa Peninsula in California's Humboldt County and on the Oregon Dunes in Coos County. It is known from ca. 15 localities (Glavich 2003, 2008).

Population and Trends

Sulcaria spiralifera was first described as two species, Bryoria spiralifera and B. pseudocapillaris (Brodo and Hawksworth 1977), which have been reclassified as one species with two chemotypes (Myllys et al. 2014). The norstictic acid chemotype (B. spiralifera) is less frequent, it is not known from Washington and it is only known from ca. 5 locations, the largest of which is the type locality on the Samoa Peninsula in California (Brodo and Hawksworth 1977, Glavich 2008). The barbatolic acid chemotype (B. pseudocapillaris) is known from the same locations as the norstictic acid chemotype in northern California and Oregon, but it occurs at an additional ca. 10 locations including some in Washington. The norstictic acid chemotype occurs further south in California than the barbatic acid chemotype. Most locations have been discovered since 2003 and the original locality discovered in the 1970's was confirmed as extant by R.T. McMullin in 2009 (Brodo and Hawksworth 1977, Glavich 2003, 2008, Glavich et al. 2005, McMullin 2015). All known localities are presumed to be extant and it is suspected that less than 2,500 mature individuals exist in the population, though further research is necessary to confirm this.

Population Trend: decreasing

Habitat and Ecology

This species is restricted to hyper-maritime dune forests. It is usually on the branches of conifer trees, predominantly on Picea stichensis and Pinus contorta var. contorta and less frequently on Abies grandis, Pseudotsuga menziesii, and Tsuga heterophylla (Brodo and Hawksworth 1977, Glavich 2003, 2005). The barbatolic acid chemotype rarely occurs on rock as well (Brodo and Hawksworth 1977).


Coastline development, climate change, and air pollution are the primary threats to Sulcaria spiralifera. This species appears to have a narrow tolerance for specific climatic conditions and its range is predicted to become warmer, increasing by as much as 1.5° C by 2050 (Mote et al. 2003). On-going coastal development and the resulting air pollution are also threats causing a decline in suitable habitat.

Conservation Actions

Several sites in California and Oregon are protected by state or federal land parcels, including Lake Earl State Park, US Fish & Wildlife Lanphere Dunes, and Samoa Dune (Bureau of Land Management, Geiser et al. 2004, Glavich et al. 2005). The barbatolic acid chemotype is ranked as S1 in Washington and G3 globally by the Washington Natural Heritage Program. The norstictic acid chemotype has a proposed rank of S1 in California and G1 globally (Glavich 2008). Regulations should be imposed to limit the development of urban and industrial areas in mature coastal dune forests in the Pacific Northwest. The impacts of climate change on the rare and sensitive habitat that Sulcaria spiralifera requires should be modelled to assist with sound conservation planning. Education and local stewardship are also needed to raise awareness and promote the conservation of this rare habitat, as are further research and conservation planning for this species. This species should be listed as a species at risk and protected by federal and state laws.

Source and Citation

McMullin, T., Stone, D., Lendemer, J. & Allen, J. 2021. Sulcaria spiralifera. The IUCN Red List of Threatened Species 2021: e.T80703106A80703113. https://dx.doi.org/10.2305/IUCN.UK.2021-1.RLTS.T80703106A80703113.en .Accessed on 5 April 2024

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