Kaernefeltia californica (current, 1996, (Tuck.) Thell & Goward)
Cornicularia californica (1926, (Tuck.) Du Rietz)
Coelocaulon californicum (1912, (Tuck.) Howe)
Alectoria californica (1910, (Tuck.) Merrill)
Cetraria californica (1859, Tuck.)

Taxon synonym: Alectoria cetrariza (1887, (Tuck.) Nylander)

Kingdom: Fungi, Phylum: Ascomycota, Class: Lecanoromycetes, Order: Lecanorales, Family: Parmeliaceae

The average size for this species is < 2-3 cm in diameter (McCune, p. 103) and is “typically richly fertile” (Thell & Goward, p. 126).

There are many misidentified records of Kaernefeltia californica in herbaria. All of the non-coastal records of the Consortium of Lichen Herbaria are most likely Cetraria merrillii or Nodobryoria abbreviata (McCune & Geiser, p. 103).

Kaernefeltia californica is a globally imperiled (G2) species endemic to the Pacific Northwest coast of North America. In the United States, it is considered to be critically imperiled (S1) in Washington, vulnerable (S3) in Oregon. It is apparently secure (S4) in British Columbia, Canada (NatureServe 2025).

The main threats to this lichen are habitat loss due to residential and commercial development, rising sea levels, and increased winter storm frequency and severity as a result of climate change.

Kaernefeltia californica is endemic to the Pacific Northwest coast of North America. It occurs in patchy locations from SE Alaska to southern California, where it is restricted to the immediate coast (McCune, p. 103). Below is a list of occurrences (in parentheses) gathered from the Consortia of Lichen Herbaria, with duplicates removed, including counties, boroughs, and provinces where the species has been recorded. 

Alaska (6): Sitka, Skagway, Juneau, Petersburg, and Bristol Bay.
Canada (25): British Columbia.
Washington (25): Clallam, Grays Harbor, King, Klickitat, Mason, Pacific, Pierce, Skagit, Whitman, and San Juan.
Oregon (55): Benton, Coos, Curry, Deschutes, Douglas, Jackson, Josephine, Lane, Lincoln, Tillamook, Linn, and Jefferson.
California (107): Alameda, Del Norte, Glenn, Humboldt, Lake, Los Angeles, Marin, Mariposa, Mendocino, Nevada, Riverside, San Luis Obispo, San Mateo, Santa Barbara, Santa Clara, Sonoma, Tehama, San Francisco, Tuolumne, Butte, Trinity, Monterey, Sonoma, San Diego, Sierra, and Napa.

When these records are filtered to 1km, which is the standard definition of an element occurrence according to NatureServe:

Alaska (2): Juneau and Hoonah–Angoon Census Area.
Canada (15): British Columbia.
Washington (6): Grays Harbor and Skagit
Oregon (18): Coos, Curry, Douglas, Lane, Lincoln, and Tillamook.
California (12): Alameda, Del Norte, Humboldt, Los Angeles, Marin, Mendocino, San Luis Obispo, San Mateo, Santa Barbara, Sonoma, San Francisco, Monterey, Sonoma, and San Diego.

The type specimen was originally collected by Tuckerman in Monterey, California in 1859 (1787FH/Tuck, holotype). In 1887, another type was recorded by Nylander in Millimak, Oregon on Pinus contorta (H/NYL35973, holotype). The oldest record is from 1864 collected by Bolander in California (UC567389). The exact location was not mentioned but was determined by Tuckerman (CLH, 2025). The number of Kaernefeltia californica herbarium records that are considered historical by NatureServe definition of >40 years old (1985) is 133 out of the 220 records (61%). 38 out of 220 herbarium records were recorded more than 100 years ago (17%).

Global Distribution (area and extent of occurrence):
Total area of occurrence: ~782,316.449 km2 (Extent of Occurrence), 300.000 km2 (Area of Occupancy)
Washington: ~ 3,671.945 km2 (Extent of Occurrence), 24.000 km2 (Area of Occupancy)
Oregon: ~3,954.417 km2 (Extent of Occurrence, 76.000 km2 (Area of Occupancy)
California: ~2060.64 mi2, 93,846.075 km2 (Extent of Occurrence), 100.000 km2 (Area of Occupancy)
Alaska: ~ 0.000 km2 (Extent of Occurrence), 8.000 km2 (Area of Occupancy)
Canada: ~93,282.842 km2 (Extent of Occurrence), 92.000 km2 (Area of Occupancy).

Country Occurrence: Canada (Graham Island, Florencia Bay, and Kwaspala Point), and the United States (SE Alaska, Washington, Oregon, and California).

The global population size of Kaernefeltia californica has been overestimated in the past due to 33% of the georeferenced herbarium records (34/102) being misidentifications of Kaernefeltia merrillii or Nodobryoria abbreviata. 70% of K. californica herbarium records are more than 40 years old; 18% are more than 100 years old; few of these sites have been revisited since the collections were made, highlighting the need for regular monitoring of rare lichen populations (CLH, 2025). 

Kaernefeltia californica global populations are inferred to have decreased significantly in the last 150 years due to habitat loss caused by coastal development and habitat structural changes. The generation length of Kaernefeltia californica is assumed to be ~15-20 years based on the length of time required for colonization of new substrate and the time required to grow to maturity and reproduce. Under generation categories, K. californica would be listed as a medium-to-long-lived: slow growing, long-term stable substratum associate (Yahr et al 2024). This species is also at increased risk of extinction and recolonization due to its small size and the fact that >50% of the global population for this species occur in small, isolated sub-populations across the species range (Yahr et al 2024). Percent decline over the last three generations (60 years, 1965) is estimated to be 11.5% (A2C Vulnerable?), based on observed and estimated declines verified through herbarium records and site revisits. 

Kaernefeltia californica is imperiled (S2) in Washington State with few isolated populations reported from Westport and Bay City area (Grays Harbor Co.) and in the northern part of the State from Fidalgo Head, Anacortes, (Skagit Co.) (Miller, J., Fertig, W., et al., p. 8). However, recent revisits to these sites showed that Kaernefeltia californica is no longer present or populations have been greatly diminished. This is due primarily to habitat loss and structural changes. It is possible that over-collecting in the early 1900’s as part of an exsiccati collection by A. S. Foster (1906-1908; Westport, WA) has contributed to the species decline in the State.

In British Columbia, Canada, Kaernefeltia californica is currently listed as S4 (apparently secure) with the majority of occurrences on Haida Gwaii, with a few additional records scattered on Calvert Island, Vancouver Island, and mainland coastal B.C. (iNaturalist 2025; NatureServe 2025).

Kaernefeltia californica is currently unranked in Alaska (NatureServe, 2025) where it is known from Juneau area (Douglas Island), Tongass National Forest (Chichagof Is.) and Gustavus area (Glacier Bay). More data is needed to assess the current population status and species range in Alaska.

Kaernefeltia californica is listed as vulnerable (S3) in Oregon where populations are concentrated along the coast in protected areas, notably Heceta Beach County Park, Oregon Dunes National Recreation Area and Oregon Dunes National Park (CLH, 2025). Populations are stable in California with many recent observations on iNaturalist and herbarium records dating back as far as the late 1800’s (CLH, 2025). There are many inaccurate records reported inland, which should be considered invalid. Kaernefeltia californica populations are restricted to the immediate coast and extend from Del Norte County in northern California to as far south as San Mateo County (iNaturalist, 2025).

Current Population Trend: Decreasing

Grows on Pinus contorta (Lodgepole Pine) and Picea sitchensis (Sitka Spruce) forests in coastal sand dunes near the ocean. Typically on conifer twigs and less often on shrubs (McCune, p. 103). However, it does colonize fence posts or other wooden structures at low elevations, usually no more than a few meters above sea level. In northern parts of its range, it will grow on twigs, cones, and bark of living P. contorta and on Pinus muricata (Bishop Pine) in other areas (Thell & Goward, p. 126).

In the northern part of its range (from south-central Alaska to the central Oregon coast), Kaernefeltia californica occurs in the North Pacific Maritime Dunes and Coastal Beaches ecosystem type, which is considered vulnerable globally (G3) and critically imperiled (S1) in Washington State (NatureServe 2025). This habitat type occurs within 2 km of the coast, and is defined by sand deposition, salt spray, wind erosion, long-shore transport, dune formations, and erosion from water from storm surges. Older dunes often have dwarf-shrub communities which provide additional substrate for K. californica (NatureServe, 2025). Dune-backed beaches cover ~40% of the Washington and Oregon coastlines; the foredunes, dune ridges that run parallel to the shore of a body of water, help coastal communities by protecting ecosystems, infrastructure, and lives from flooding and erosion during extreme winter storms (Mull, 2010).

In the southern part of its range, Kaernefeltia californica occurs in the Californian Coastal Beach, Dune & Sandy Bluff ecosystem type is considered vulnerable globally (G3) based on factors such as the ecosystem range being moderately extensive, potential for long-term decline of this ecosystem being moderate to high, and threats high from invasive species and development (NatureServe, 2025). This ecosystem consists of short (<1 m tall) shrublands on coastal sand dunes and beaches with persistent onshore winds and salt spray. 

Systems: Epiphytic

Habitat loss due to residential and commercial development is the primary threat to Kaernefeltia californica. Across the Washington and Oregon coastline, residential housing development, agriculture, commercial fisheries, dredging for shipping channels, and upland logging have been supporting factors in loss of coastal habitat and species decline (Huppert, et al., 2003).

As an example, Westport Light State Park, Grays Harbor County, WA, is one of the only known localities in the state where this species has been successfully relocated in the last 40 years. This location is currently being threatened by development into a golf course and the decision will be made in summer 2025 as to whether the golf course proposal will move forward by Washington State Parks and Recreation Commission.

The ecosystem where Kaernefeltia californica grows, The North Pacific Maritime Dunes and Coastal Beaches ecosystem, is considered vulnerable globally (G3) and critically imperiled (S1) in Washington state (NatureServe 2025). 

In the southern extent of the species range, K. californica occurs in the Californian Coastal Beach, Dune & Sandy Bluff ecosystem type (vulnerable globally-G3). 

Rising sea levels pose a threat to the narrow band of coastal habitat that Kaernefeltia californica is restricted to along the PNW coast of North America. In particular, populations in Washington state have the highest level of threat due to the critically imperiled status of the habitat. Within 3 generations (~15-20 years), the probability of sea level rise for the area of Westport, Washington is predicted to be up to 3.8-5.8 ft, which would lead to significant flooding and erosion of Kaernefeltia californica habitat (Stevens, 2021).

Increased winter storm frequency and severity as a result of climate change. Kaernefeltia californica is restricted to the immediate coast within earshot of the ocean so more frequent and severe storm surges will directly impact K. californica’s habitat by inundating and killing the shore pine (Pinus contorta) forests. These impacts have already been observed along the WA coast in places like Deception Pass State Park (Island County) where significant storm damage caused by high winds and massive waves destroyed coastal dune habitat in January 2024.

Invasive species such as non-native dune grasses (Ammophila arenaria & A. breviligulata), as well as Scotch broom (Cytisus scoparius) pose additional threats to Kaernefeltia californica habitat. These species have stabilized the dunes, leading to rapid succession of dense shore pine forests, altering plant community structure and microclimates necessary for K. californica. The denser shore pine forests have rapidly expanded across dunes, leading to reduced air flow and lower light levels. These conditions lead to heavy colonization by bryophytes and more shade-tolerant lichens that outcompete K. californica (Mull, 2010; Rossman & Dunwiddie, 2021).

Re-survey historical collection sites for Kaernefeltia californica to determine current population status.

Conduct new surveys of suitable habitat in coastal areas to locate potentially new populations, especially in Washington state where populations appear to be at high risk of extirpation. 

If the species is found, record data on population size and health, but do not collect specimens, because over-collection is thought to be a contributing factor for the species decline.

Disseminate updated conservation assessments (i.e. IUCN Red List, NatureServe, WHNP) to educate land managers about threats and declines.

Develop a detailed conservation and management plan for Kaernefeltia californica and other rare lichens at sites where it occurs.

Due to this species being identifiable through photographs, using platforms like iNaturalist is helpful in documenting its presence.

Whether or not this lichen has an economic importance, cross checking listed herbariums for correct species, and revisiting historical sites. There are many misidentified herbarium records of Kaernefeltia californica. All of the non-coastal records of the Consortium of Lichen Herbaria are most likely Cetraria merrillii or Nodobryoria abbreviata.

Not economically significant/not known.