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 haasii is associated mainly with Abies spp (Abies alba, A. nordmanniana), sometimes also with Pinus sylvestris. Its major habitat is montane, calcareous Abies- or Abies-Picea-Fagus forests of C and S Europe, a forest type with many habitat-specific taxa of Cortinarius, subgenus Phlegmacium.
The Phlegmacium-rich, calcareous Abies or mixed Abies-Picea-Fagus forests often occupies small and fragmented areas, and the habitat is vulnerable of habitat loss due to urbanization, lime quarries, shift in tree species (uniform Picea plantations) etc, and to decreased ecological conditions due to modern forestry (with clear-cuts).
Global red-list assessment: The species is known from 50 localities in Europe/globally. The total population is estimated to approx. 150(-200) localities, which is equivalent to approx. 3 000(-4 000) individuals according to IUCN standards. According to the C criterion (C2 a(i)), the species becomes red-listed as VU, based on a continuous decline, population size <10 000 individuals and very small/isolated subpopulations.
According to present data, Cortinarius haasii is mainly distributed in the montane regions with (mixed) Abies alba forests of the Jura and Prealps. It is known also from the Pyrenées and W Carpathians, and occurs SE to the Abies nordmanniana forests of W Caucasus. Probably the species has a wide distribution within the natural Abies alba range of the Carpathians, the Italian Apennines and the Balkan-Greech mountains (but the calcareous fir forests are little investigated in most of these regions). Outside the natural Abies forest range, the species is recorded under Pinus sylvestris in E Spain and SE Sweden (Gotland).
The element of habitat-specific taxa of calcareous Abies forests are never found outside Europe, e.g. never found within the Abies sibirica range of Asian Siberia, and never recorded in N America. In other words, this element is according to present knowledge assumed to be strictly European (at least when the Abies nordmanniana range of N Turkey is included).
Cortinarius haasii is known from 50 sites/localities in Europe/globally; approx. 10 sites from N Europe/SE Sweden, 3 from NE Spain, 1 from the Czech Republic, and the rest from the Jura-Prealps-Black Forest region. The total population is estimated to approx. 150-200 sites/localities, which is equivalent to approx. 3 000-4 000 individuals, according to IUCN standards.<10 000 individuals and very small/isolated subpopulations. The decline of the calcareous Abies forests (or mixed Abies-Picea forests) in the evaluation period (last 50 years) is estimated to be in the magnitude of 15-20%. Based on this, the species becomes red-listed as NT according to the A-criterion (A2c + 3c + 4c) (species/habitat decline >
According to the C criterion (C2 a(i)), the species becomes red-listed as VU, based on a continuous decline, population size
Population Trend: Decreasing
Cortinarius haasii is associated mainly with montane calcareous, herb-rich-mossy Abies or Abies-Picea-Fagus forests, where it forms mycorrhiza with Abies alba, possibly also with Picea abies in areas with mixed Abies-Picea forests; in Caucasus with Abies nordmanniana. Southwest and north of the natural Abies alba forest range, the species occur in calcareous, herb-rich pine forests, where it forms mycorrhiza with Pinus sylvestris (NE Spain, SE Sweden). The species regularly occur together with other species of the calcareous Abies forest element, such as C. atrovirens, C. citrinoolivaceus.
Cortinarius haasii and its habitats (calcareous Abies(-Picea) forests, calcareous pine forests) have been declining e.g. due to areal loss (urbanization, including tourist resorts, expansion of limestone quarries, shift from Abies stands to Picea plantations) as well as decreased habitat quality/ecological conditions due to modern forestry with clear-cuttings. Forest statistics from Austria indicates that forestry activity has been doubled the last 40 years, and according to a habitat-redlist in Austria, the Abies-Picea forests are endangered in many regions of Austria.
To prevent decline and further fragmentation of calcareous Abies (-Picea) forests and calcareous Pinus forests with good habitat quality, it is important to set aside reserves on calcareous hotspots, housing many rare/redlisted, habitat-specific species such as C. atrovirens, C. citrinoolivaceus and C. haasii. It is furthermore important to establish also sites with a less strict conservation regime, such as woodland key biotopes, where some non-destructive human activities are accepted (such as non-intensive forestry, with closed cutting).
More mapping/surveying and monitoring of C. haasii is needed. More data on occurrences in the little studied calcareous Abies alba forests of the eastern Carpathians and the montane regions of Balkan is especially needed. Finally, more documentation on the degree of decline of the habitats themselves is needed.
Brandrud, T.E. 2000. Some distribution patterns of Cortinarius subgenus Phlegmacium species in Europe. J. Journées Européennes Cortinaire 2: 49-55 [Engl. version].