Cortinarius cupreorufus is a characteristic and rather well-known indicator species of the rich mycorrhizal fungus element being restricted to calcareous coniferous forests. The species iswidespread but rare in Eurasia and N America, and is suffering from decline of calcareous coniferous forest types, due to e.g. areal loss in more heavy populated areas and loss/fragmentation of older coniferous forest stands from modern (clear-cut) forestry.
Preliminary global and European Red List assessment;
NT (A2c+3c+4c), with an estimated decline of >15%during evaluation period of 50 years.
The estimated decline is due to a long-term and persistent decline in mature/old-growth forests of calcareous coniferous forests.
Belonging to a bicentric boreal-montane coniferous forest element in Europe. Rare, but widespread within the areas of Cortinarius subgenus Phlegmacium-rich, calciphilous coniferous forests in (i) N Europe and (ii) montane-subalpine regions of C and S Europe. The species is also reported from N Asia (Russia) and western North America.
The species is known from 125 localities in Norway, 120 localities in Sweden, and probably approx. the same in Finland. The real number of localities in Fennoscandia is estimated to approx.. 3000, and the real number in N Europe could be 4000-5000 localities, when adjacent areas of Balticum and Russia are included. The species seems somewhat rarer in the montane-subalpine coniferous regions of C Europe, with a rough estimate of 3000-4000 localities; altogether approx.. 7000-9000 localities in Europe. (Few data are available on localities in C/S Europe; according to literature, approx.. 32 localities were known from this area per. 2000; according to recent databases and literature, approx.. 40 localities are known from Austria, 13 locs. From Slovenia, and 23 locs. in Baden-Württemberg, SW Germany.)
The species is recorded almost north to the northern border of Picea abies forests in N Fennoscandia, and south to NE Spain (Pyrenees 1400-1500m a.s.l.) and C Italy (N Apeninnes). Distribution in E Europe little known, but recorded from Poland, probably widely distributed in the Carpaths. The species are recorded from three regions of Russia, including Asian parts.
The species seems to be very rare west of the natural distribution area of Picea abies, but a few outposts are recorded in the Pyrenees (Abies alba forests) and in the fjord districts of Norway (Pinus sylvestris forests). The species occurs high up in the subalpine spruce forests both in C Scandinavia and in the Alps, and occurs near the arctic timberline in N Finland.
The species is reported from various parts of (montane) Western North America north to the Olympic peninsula, Washington.
The species is mainly associated with older coniferous forest stands, without influence of modern forestry with clear-cuts. In some, very calcareous areas, it may also (re-)establish in younger, planted forests, due to a high dispersal pressure from adjacent, larger populations in older forests.
Cortinarius cupreorufus is included in a number of European red data lists (e.g. of Austria and Germany). It is redlisted as NT (C2a(i) in Norway, and as VU (A2c+3c+4c) in Sweden. The estimates of decline of the species and its habitat (calcareous coniferous forests) varies from approx 10% to >30% decline in the evaluation period (50 y) in Fennoscandia. Calcareous pine forests (NT) and calcareous spruce forests (VU) is redlisted as nature types in Norway, and calcareous coniferous forests types (including e.g. calcareous pine forests of the Carpaths) are on the natura 2000 list. A decline of >15% during 50 years seems realistic for Europe as a whole.
In a European-global perspective, we therefore suggest the species to be redlisted as NT (A2c+3c+4c; C1+2a(i)).
Population Trend: Deteriorating
Cortinarius cupreorufus is growing in calcareous coniferous forests, often in deep moss, in dry, shallow soil on limestone outcrops/ridges, sometimes in seasonally ground water influenced habitats or along brooks/creeks. In Europe, it is associated mainly with Picea abies, but also with Pinus sylvestris and Abies alba. In North America probably also with other conifers such as Pseudotsuga menzieni. The species produces large fairy rings in optimal habitats. The species is an important indicator/signal species for calcareous forests with a rich funga of conservation value, with many specialized and rare species (rich hot spots).
The species is threatened by loss, depauperation and fragmentation of intact, calcareous coniferous forest habitat, due mainly to intensive forestry with clear-cuts. The species seems, especially in northern areas, to suffer from re-establishment in production forests with a (clear-cut) turnover period of less than approx. 80-100 years. The species seems also favoured by a moderate level of disturbances such as moderate forest fires and cattle grazing in forests, keeping the forests in a semi-open stage, with openings in the forest floor (small tracks/paths, etc.) and preventing a too heavy humification/acidification of the top soil overlying the calcareous layers.
To prevent decline and fragmentation of calcareous coniferous forests with good habitat quality, it is important to set aside reserves on calcareous hotspots, housing many rare/redlisted species such as Cortinarius cupreorufus. It is furthermore important to establish woodland key biotopes and similar kinds of forest stand where a non-intensive, closed cutting is performed, leaving much of the stand qualities intact, including a continuity in the spruce roots and their mycorrhizae.
Population dynamics, with emphasis on the species needs for old-growth forests, as well as the response to small scale forestry with closed cutting should be further studied. There is a need for further mapping/surveying of the species, to develop a good picture of its wide distribution on the northern hemisphere.
Brandrud, T.E. 2000. Some distribution patterns of Cortinarius subgenus Phlegmacium species in Europe. J. Journées Européennes Cortinaire 2: 49-55[Engl. version].