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.
Cortinarius prasinocyaneus is an extremely rare fungus forming ectomycorrhiza with hazel (Corylus) and lime (Tilia) in calcareous, broadleaved forest with long history of forest coverage in climatically favourable situations. The species seems to have high requirements and a very narrow ecological niche, only occurring on “hot-spot locations” widely dispersed in the landscape.
Very few known localities world-wide (Sweden 6, Norway 1, France ?, Hungary 1), small population and confined to a rare, fragmented and threatened habitat. These threats is often of two major causes: 1) Clear-cutting and other silviculture activities replacing the original vegetation with other forest-types or 2) Abandonment of extensive grazing, cutting and other small-scale disturbances causing changes in lignose species composition and “densification” of habitats.
Cortinarius prasinocyaneus represents a large number of similarily rare and ecologically very demanding species with small populations and limited availability of habitats under various threats from change in landuse. Also, these localities are often very fragmented. The localities and habitats for many of these species, incl. C. prasinocyaneus can be looked upon as sites of major importance for conservation of biodiversity.
Easy to identify and relatively well studied. Known from a handful of countries in Europe and probably in a very small total population. Disjunct distribution with few localities in each area (Norway, Sweden, France). Nowhere common and seems to have very narrow (allthough not easily understood) ecological niche.
AOO very small and distribution fragmented. Probably not more than 20 localities known globally, 10x gives estimation of 100 (20-200) localities. No. of ind acc to template gives 2.000 mature individuals, no subpopulation with more than 250 individulas. Decrease in area, distribution and quality of habitat.
Suggestion: EN on C2a(i)
Only known from Europe and probably restricted to western parts of Eurasia.
Easy to identify and relatively well looked after. Known from a handfull of countries in Europe having a very small total population. Disjunct distribution with few isolated localities in each area (Norway 1 locality, Sweden 6, France ? and Hungary 1). Redlisted or suggested for redlisting in all countries where it occurs. Seems to have very narrow ecological niche in a habitat that is deteriorating.
AOO very small and distribution fragmented. Probably not more than 20 localities known globally, 10x gives estimation of 100 (20-200) localities. No. of ind acc to template gives 2.000 mature individuals, no subpopulation with more than 250 mature individulas. Decrease in area, distribution and quality of habitat suggests EN on C2a(i).
Population Trend: Decreasing
A mycorrhiza-species with Corylus and Tilia confined to calcareous, xerothermic forests with long history of semi-open forest coverage. Needs shallow soils over rocky calcareous bedrock (leptosols) and warm and favourable situations. In Sweden the most characteristic habitat is low and more or less mosaic Corylus-stands (often together with Quercus robur) in extensively grazed areas with warm local climate and extremely high pH in soil profiles. Often also close to forest edges, wetlands, streams etc. where plenty of sunlight reaches the sites for the mycelium.
Felling of host trees and other forestry actions which results in changes of lignose composition, demography and densness are the main threats to Cortinarius prasinocyaneus. Change of land use, i.e. abandonment from earlier use as extensive semi-natural grazing habitat and small scale cutting resulting in semi-open forest ecosystems, are also negative. Finally the very small global population size and obviously fragmented populations constitutes a major threat.
Cortinarius prasinocyaneus could be considered an indicator species for a community of similarily rare and ecologically very demanding fungal species (mainly ectomycorrhiza but also some saprotrophic) with small populations and limited areas of habitats. Localities can be looked upon as sites of major importance for biodiversity and in need of conservation plans.
The remaining habitats are also very fragmented cross the total distribution area and even smaller AOO can be expected in future. This group of species needs a special conservation action plan incl. the following measures 1) Site/area protection 2) Managment and restoration of habitats and 3) Awareness of mycorrhiza-species biology and importance in eco-systems.
Dima, B. & Albert, L. 2009. NÉGY RITKA CORTINARIUS FAJ (AGARICALES, BASIDIOMYCOTA) MAGYARORSZÁGRÓL. Clusiana 48(2): 133-144.
Jacobsson, S. Faktablad Cortinarius prasinocyaneus. Link: http://www.artfakta.se/Artfaktablad/Cortinarius_Prasinocyaneus_1990.pdf.
Fröslev, T. & Jeppesen, T. 2007. Interesting species of Cortinarius subgenus Phlegmacium from broadleaved forest in Scandinavia. Svampe 56: 43-56.
Laurent, P., Muller, J-L., Schott, D. 2014. La Liste rouge des Champignons supérieurs menacés en Alsace. Avis favorable émis par le Conseil Scientifique Régional du Patrimoine Naturel le 4 décembre 2014. Link: http://odonat-alsace.org/sites/default/files/equipe/Listes_rouges/LR_Champignons_Alsace_2014.pdf
Knutsson, T. & Soop, K. 2005. Un nouveau cortinaire de la section Calochroi. Journal des JEC 7: 51-55.