Masonhalea richardsonii is a large foliose lichen that is widely distributed in unglaciated Beringial arctic habitats of eastern Asia and western North America. The species has been nominated to be the official lichen of the Yukon Territory in Canada. It is not under significant threat at this time and is assessed as Least Concern.
Masonhalea richardsonii was described nearly two hundred years ago and consistently recognized with the same taxonomic concept since that time. It is a large, morphologically unique lichen with a distinct tumbleweed-like life history.
Why suggested for a Global Red List Assessment?
This species occurs across Beringial habitats in arctic Asia and North America. Most known occurrences are from Alaska, U.S.A. and Yukon Territory, Canada. There are scattered records from eastern Russia and the species is likely more widespread in that region than the data indicate.
Population and Trends
Detailed population data are not available for this species. Based on recent occurrences (>1970) the population is suspected to be stable as the species is widely distributed and often locally abundant where it occurs.
Population Trend: Stable
Habitat and Ecology
Masonhalea richardsonii primarily inhabits arctic tundra, as well as alpine heath and subalpine heath habitats. It grows free-living on the ground and its transient movement is likely facilitated by wind and animal mediated dispersal. It has a tumbleweed like life history and individuals frequently aggregate in tundra depressions. The species serves as forage for tundra caribou (Holleman & Luick 1977).
Detailed demographic and fine-scale modern occurrence data from comprehensive systematic surveys would fill in knowledge gaps for this species and facilitate a more accurate population assessment. Although it is assessed as Least Concern, long-term monitoring of populations would be beneficial for future assessments and detecting potential declines or extirpations that may result from ongoing large-scale changes its arctic habitat. Specific changes to the habitat that may impact this species include conversion of tundra habitat to shrub and forest vegetation, melting of permafrost potentially resulting in alterations to the depressions where the species aggregates, declines in the caribou population that may impact dispersal and reproduction. Many sites where this species occurs are located on public lands and in protected areas where it is incidentally protected.
Population size, distribution & trendsPopulation trendsHabitat trends
Use and Trade
This species has been reportedly used as fire kindling in Alaska (Brodo et al. 2001) and is collected by biologists studying its distribution and biology.
FuelsSport hunting/specimen collecting
Masonhalea richardsonii in the field in the Yukon Territory. Photo: J.C. Lendemer.