R-L categories correct, but text here does not match final assessment. Updated version will be published in IUCN´s Red List June or Nov 2019.
Stereopsis vitellina is yellowish, stipitate corticioid fungus with the reduced stipe and pileus forming fan or rosette shaped structures (Eriksson et al. 1984). The species is mycorrhizal and is confined to old growth dry Pinus forests with long continuity of trees and decaying wood with traces of wildfire (Arnolds & Veerkamp 2008). It is vulnerable to clear-cutting, fragmentation, reduces the amount of dead wood and suppressed forest fire.
Sandy oligotrophic pine forests are declining due to land use and urbanization, wood harvest and eutrophication coursed by atmospheric nitrogen deposition. The decline in area and quality of suitable habitat possible exceed > 30% during the past 50 generations (three generations) and is predicted to continue. Currently, the population size of mature individuals 60000, hence criterion A is applied. The species meets the category vulnerable (VU) under criteria A2c+3c+4c.
Stereopsis vitellina wood decomposer or mycorrhizal species found in old-growth pine forests under coarse pine logs or on soil under roots or in mole- or vole galleries. It grows in the sandy pine forests where rare stipitate hydnoid fungi also grow. The potential habitat of Stereopsis vitellina decreasing due to harvesting of old – pine forests on sandy soil, removal of coarse woody debris, regulation of fire.
Stereopsis vitellina has its core distribution in North Europe with the main subpopulation in Fennoscandia. In Norway, all localities are in southeastern part. In Denmark, it occurs in central Jutlandia. The species was recently after many years rediscovered in Scotland (Gurney 2015). It is also reported from several localities in the coniferous forest from the Czech Republic, Estonia, Germany (database), The Netherland (Arnolds & Veerkamp 2008), Lithuania and in Russian Karelia (Kotkova 2017).
Stereopsis vitellina is currently known from ca. 300 localities. In Sweden, it is the estimated number of localities ca 200. Its potential habitat, old forests of Scots pine on sandy soil has decreased sharply and continue to decrease due to logging. Evaluated as VU (Artdatabanken). In the southeastern part of Norway known from 20 localities, evaluated as VU. Assumed ongoing reduction in habitat and population over three generations. In Finland, the species is known from most of the country and considered the least concern (LC). In Denmark known from seven localities restricted to the northern part. In Scotland it has known from ca. 60 localities all in Caledonian pine forests. Very rare and declining in several European countries. In the Netherland recorded from 11 localities till 1990, and 4 between 1990-2018 and evaluated as critically endangered (CR) (Arnolds & Veerkamp 2008). Several localities in Belgium, Czech Republic, Estonia, Germany, Lithuania and Russia.
The real number of localities may be 10 times higher and are estimated ca. 3000 localities. Maximum mature individuals inferred 60000 assuming 20 mature individuals in a locality (2 gentes x 10 ramets).
The population and its habitat (old-growth, dry sandy pine forests) is declining and are probably decreasing by more than 30 % in three generations (50 yr). Such forests are threatened by clear-cutting and the species seems have difficulties to establish in younger forests after cutting because of removal of coarse woody debris which is suitable for fruit body attachment. Dry pine forests of Calluna type changes due to nitrogen depositions and absence of wildfire.
Stereopsis vitellina is an ectomycorrhizal fungus restricted to old growth dry Calluna type pine forests with long continuity of trees and decaying wood, often burned in a wildfire. This forest type is usually rich in red-listed fungi (Westerberg & Karström 2009). It is found mostly on humid, exposed soil under roots, in mole- or vole galleries, under coarse pine logs overgrown by mosses and shrubs like heather, blueberry, in a hole of charred rootstock of pine. It is a stipitate resupinate fungus forming 2-3 cm tall, soft and fragile fruit fan-shaped basally tapering to a stipelike part (Eriksson et al. 1984). The fresh fruit body yellowish-white to yellow or pale ochraceous then dry.
Stereopsis vitellina is strongly affected by clear-cutting of old-growth pine forests, removal of dead wood, nitrogen fertilization of forests and measure to prevent forests fires.
To prevent decline and fragmentation of old sand pine fortes, to leave a sufficient amount of coarse dead wood, to protect the larger continuous area where the species occurs.
The species is not known to be used.
Arnolds, E., Veerkamp, M. 2008. Basisrapport rode lijst paddenstoelen [Basic report on red list of fungi]. – Nederlandse Mycologische Vereniging, Utrecht. (in Dutch).
Eriksson, J., Hjortstam, K., Ryvarden, L. 1984. The Corticiaceae of North Europe, vol 7. Fungiflora, Oslo.
Gurney, M. 2015. Gains and losses: extinctions and colonisations in Britain since 1900. Biological Journal of the Linnean Society 115: 573–585.
Kotkova, V.M. 2017. New data on aphyllophoraceous fungi (Basidiomycota) of the protected areas of the Leningrad Region. IX. Natural Park «Toksovskiy» (Karelian Isthmus). Novosti Sistematiki Nizshikh Rastenii 51: 166-177 (in Russian)
Westerberg, S., Karström, M., 2009. Vedrester I våra tallskog hyser daldisar bland swamparna. Svensk Mykologisk Tidskrift 30: 9-16.