This species has a very restricted range, and is known from only one locality. This site is under protection and no declines are currently known, but the situation should be carefully monitored. The overall population size is estimated to be very small, with a maximum of 200 mature individuals, but a more likely estimate of only 30 mature individuals. Therefore, this species is precautionarily assessed as Critically Endangered under criterion D.
The species is characterized by the cupuliform creamish basidiome growing specifically on bark of living Saxegothaea conspicua. Microscopically it is characterized by the stratose hymenial configuration, acanthobasidia, acanthophyses, gloeocystidia and globose and verrucose basidiospores (Gorjón et al. 2013).
Aleurodiscus stratosus is a very rare corticioid fungi living on bark of Saxegothaea conspicua only known from the temperate zone of Argentina. The ongoing decline of its host tree of in combination with its fragmentation and rareness, considering undiscovered sites, and the only know location of this species despite the intensive search in its host, results in it being assessed as Endangered (EN) under the criteria:
B2ab(v) EN: this criterium applies because area of occupancy estimated to be less than 500 km2, Severely fragmented or known to exist at no more than five location
D EN: this criterium is applied on the basis of population size estimated to number fewer than 250 mature individuals.
Host presents a decreasing population trend frequently altered by the action of man. Not found in surveys in neighboring Chilean forests (Gorjón & Hallenberg 2012).
It is known only from one locality in Neuquén, Argentina (Nahuel Huapi National Park at Puerto Blest). It has been searched for but not found in Chile (Gorjón and Hallenberg 2012).
The population trend is unknown, but it is possibly decreasing. The species is known from one location. There are probably only 100 trees that this species could occur on in this area, and out of c. 20 trees that have been checked it has been found on three. Therefore, assuming there are two mature individuals per tree, the overall population size is likely to be c. 30 mature individuals (maximum 200).
Population Trend: Uncertain
This species grows on bark of living Saxegothaea conspicua. The only location where this species has been found is very humid.
In Argentina, the host of this species, Saxegothaea conspicua is restricted in distribution and confined to national parks. In Chile, conversion of native forest in the coastal Cordillera to commercial plantations of Pinus radiata and Eucalyptus, means that much of the potential habitat for Saxegothaea conspicua has been lost and continues to disappear, but A. stratosus has not been recorded from Chile. Where A. stratosus itself is known to occur, it is fairly well protected, although tourism could be an issue.
It is necessary to protect the only known host of this species and its habitat. Education and awareness initiatives in the area could minimise impacts on the species from tourism.
The potential for this species’ presence in Chile needs to be assessed. Knowledge of factors affecting its limited distribution within the host range are needed. Work to understand the best management practices for the host species would be useful. Research into the taxonomy, population size, distribution and trends of this species and its host would be useful too.
There is no use/trade of this species.
Gorjón S.P., Greslebin A.G., Rajchenberg M. 2013. The genus Aleurodiscus s.l. (Stereaceae, Russulales) in the Patagonian Andes. Mycological Progress 12:91-108.
Gorjón S.P., Hallenberg N. 2012. Some new species and a first checklist of corticioid fungi (Basidiomycota) from Chile. Mycol. Progress 12:185-192.