Assessment prepared by Clayton Merideth from Albuquerque BioPark
Iceland Moss (Cetraria islandica) is a broadly distributed fruticose, terricolous lichen. It occurs in boreal and tundra habitats in a Holoarctic range, as well as montane areas of Colombia, southern Australia, New Zealand, Patagonia, Antarctica, and several Antarctic and sub-Antarctic islands. In portions of its range, the species may form the dominant ground cover species and its population is thought to be very large, though decreasing in number. (Sinigla et al. 2015). It occurs in relatively open boreal forest and tundra habitats, preferring heaths, dunes, coastal plains, lichen woodlands, bogs, and meadows. It is used for a wide variety of applications including as a food source for humans and livestock, as a dye, and as a medicine. The species is threatened by air pollution, habitat loss, range contraction caused by climate change, and excessive harvest. Despite these threats, the species’ extremely large range and population makes it unlikely to be at risk of extinction range-range wide. It is therefore listed as Least Concern.
Iceland Moss (Cetraria islandica) has a Holarctic distribution. In North America the species is reported from Alaska, Canada, Greenland, and portions of the contiguous United States ranging southward into the Appalachian, Ozark, and Rocky Mountain ranges (CNALH 2020, Matthews 1993). In Europe the species ranges from Svalbard and Iceland south to mountainous areas of the Iberian Peninsula, Italy, the Balkans, eastern Anatolia, and the Caucasus Mountains. Its distribution extends eastward into Japan (CNALH 2020, GBIF 2020). The species is also reported from Colombia (Ramiro Fonnegra and Jiménez Ramirez 2007), Patagonia, Tierra del Fuego, the Falkland Islands, South Georgia, Papua New Guinea (Mt. Wilhelm), Australia (New South Wales, Tasmania, and Victoria), and the South Island of New Zealand (McCarthy 2020). It occurs at elevations ranging from 0 to 4,500 meters (GBIF 2020).
EOO: >100,000,000 km2 (Estimated based on GBIF occurrence data using GeoCat tools.)
Elevation range: 0-4400
Map notes: Point data derived from SEINet (2019) and GBIF (2019).
Occurrence: Nearly everywhere.
In portions of its range, the species may be the dominant ground cover species (Matthews 1993). Given this, and its extremely large range, it is likely to have a very large population which certainly does not meet any thresholds for listing under a threatened category. The species may have a disjunct and sporadic distribution at the temperate margins of its range where it is considered to exist in secondary habitats. In montane regions such as these, the range of the species is likely to be contracting as a result of climate change (Sinigla et al. 2015). Given the nature of threats to the species, the population is likely to be in decline.
Population Trend: Decreasing
Iceland Moss is a fruticose, terricolous lichen species (Sinigla et al. 2015). It occurs in relatively open boreal forest and tundra habitats, preferring heaths, dunes, coastal plains, lichen woodlands, bogs, and meadows (Matthews 1993, McCarthy 2020)
The species is utilized as forage by caribou, mountain goats, moose, and muskox (Matthews 1993).
Threats to the species include susceptibility to several forms of air pollution, habitat loss, increasing fire frequency in much of its range, contractions in range caused by climate change, and unsustainable harvest. Air pollution is likely to be the largest contributor to population declines. The species accumulates heavy metals and radioactive fallout deposited in soils within its range (Outola et al. 2003). The specific impact of heavy metal contamination on Iceland Moss population has not been well studied and heavy metal contamination may present a greater threat to consumers of Iceland Moss which would be subject to greater exposure through bioaccumulation, particularly at higher trophic levels. Of greater concern, is the species’ intolerance of sulfur dioxide emissions which have contributed to significant habitat losses in Europe (Hauck 2008).
The species is intolerant of fire (Matthews 1993) and may be threatened by changing fire regimes in boreal forest habitats attributed to global climate change. Rapid temperature increases and altered precipitation regimes have resulted in significant changes to forest composition in large areas of boreal forest (Baltzer et al. 2019, Hart et al. 2019, Whitman et al. 2019). Collectively, these changes may result in a shift toward increasing fire frequency in much of the species’ range. Given the species’ slow growth rate (Matthews 1993), it is likely that increased fire frequency and intensity will have detrimental impact on the species.
The impact of range shifts caused by climate change has not been modeled for this species, but range shifts are likely to have the greatest impact on montane subpopulations in at lower latitudes. Harvest of the species occurs at high levels, particularly in Iceland and Scandinavia, which may lead to localized population declines (Blumenthal 2000).
The species incidentally occurs in many protected areas (IUCN and UNEP-WCMC 2020). At the margins of its range (including in Hungary and Tasmania) it is considered threatened or rare (Sinigla et al. 2015, Threatened Species Section 2020).
The species has been used for a large number of applications for several centuries and is commercially available in several forms today. Medicinal applications of the species include as a cough suppressant, and anti-inflammatory. Several compounds, including usnic acid, produced by the species have also been investigated for anti-cancer properties and as a treatment for ulcers. The species is currently available in lozenges intended to treat upper-respiratory tract ailments, and as a flavoring agent for liqueurs (marketed as Fjallagrasa) (Blumenthal 2000, Iceland Products 2020). Culinary uses of the species include use as a flour substitute, as a gelling agent, and, during times of famine, as a feedstock for molasses production. The species is also used in the production of brown dyes (Blumenthal 2000). It may also be used as a feedstock for cattle and pigs (Matthews 1993).