Amylocystis lapponica is a widespread circumboreal wood-decaying fungus in coniferous forest ecosystems in Asia, Europe and North America. It grows in old-growth humid forest within coarse logs of predominantly Norway spruce, Sitka spruce and Engelmann spruce. Amylocystis lapponica is nationally red-listed in northern Europe (Fennoscandia) as its habitat is in decline due to clearcutting and it is used as an indicator species for old-growth forests. In North America, there is no evidence of decline and the status in boreal Asia is unclear. Therefore, it is globally assessed as Least Concern.
Preliminary European red-list assessment; NT close to VU (A2c+3c+4c), population decline approaching 30 % during the last 30 years and the decline is expected to continue at the same speed in the next 30 years. The past, ongoing and expected decline may exceed 30%, if so VU. Evaluation period (= 3 generations) is considered to be 30 years for A. lapponica.
Records in the Sierra Nevada and Cascade ranges (in California, Oregon and Washington) may represent a distinct species, as these fruit on Abies magnifica and A. concolor, often in the spring following snowmelt.
Amylocystis lapponica has a circumboral distribution; Asia, Europe and North America. Outside the boreal zone, appropriate habitat is sparse. It is reported from a few central European countries and the Changbaishan Nature Reserve in north-eastern China.
In Europe, A. lapponica occurs almost exclusively in boreal old-growth forests with Picea abies. The majority of known European localities are situated in Sweden and Finland, albeit it is likely that the population is larger in European Russia. The number of known localities in Europe was estimated to 1000 in 2015 (Fraiture & Otto 2015). A large portion of the appropriate habitat of old-growth forests for A. lapponica have been cut during the last half century due to forestry in northern Europe and the major part of remaining appropriate forests is expected to disappear within the next 50 years. Not or only sparsely recorded in managed forests. In Finland and Sweden, the populations are estimated to have declined by >15% since 1985. In Norway it is assessed to have declined by >30% since 1985. It has not been assessed for national red-listing in Russia, but is included in several regional Russian Red Lists, e.g. the Sverdlovsk Region (Shiryaev et al. 2010) where it is assessed as VU. Its status in the boreal parts of Asia is poorly know.
In North America it is widespread and locally common, occurring across the northern latitudes, and south in the mountains. It is currently (2018) known from ~300 locations, but is considered under reported, and a large amount of suitable habitat have not been surveyed for this species. In north-east NorthAmerica it occurs both on native spruce forests, and in some Norway spruce plantations. There are scattered reports (on Mycoportal) from Quebec and Ontario; the Canadian National Mycological Herbarium (DAOM) has not been digitized, and accessible data is lacking. It occurs in the Rocky Mountains, from Arizona and New Mexico, USA in the south, north into British Columbia and Alberta, Canada. It also is fairly common on the Pacific Coast, from Humboldt County, California into south-central Alaska (roughly following the range of Sitka Spruce).
Population Trend: Decreasing
Amylocystis lapponica is a wood-decomposing fungus causing a brown rot. It was originally described (from Lappland) on Abies although nowadays in Europe it is found almost exclusively in coarse fallen logs of Norway spruce (Picea abies), larch (Larix) and rarely on pine (Pinus) in uneven-aged virgin old growth forests and forests historically subjected to selective cutting with a long continuity of logs. It occurs in forests with high humidity, typically spruce swamp forest, herb-rich mesic-moist spruce forest and mountain spruce forests. It is used as an indicator species for old-growth forests and woodland key habitats. It does not seem to be present in managed forests in Europe. The sporocarp is annual while the mycelium is long-lived and potentially present in logs for many decades. The mycelia of A. lapponica seem largely to be located in the inner parts logs. In North America it grows on Sitka Spruce (Picea sitchensis) on the Pacific coast, and in the Rocky Mountains from Arizona north into Canada; especially on Engelmann spruce (Picea engelmannii). It is also found on Abies magnifica in the Sierra Nevada.
The main threat is clear cutting and transforming of old growth forests with high amount of coarse woody debris into managed forests with shorter rotation times and few of coarse logs. Forest certification recommends certain conservation considerations for forest management, however implementation of these is only expected to slightly diminish the expected continued large decline in the population of A. lapponica. There is no immediate threat in North America.
Setting aside forest reserves occupied by A. lapponica in which there is a continous formation of coarse dead wood (logs) of Norway spruce. If site protection is not possible, A. lapponica may survive clearcutting if large areas (>0.5 ha) with dead wood are set aside for nature conservation within the area to be cut. Similarly, restricted selected cutting management may be the next best option if sufficent areas with dead wood are set aside for nature conservation.
There are some apparent ecological differences between European and N. American populations. In N. America it occurs in Picea plantations and whereas it seems to fruit late in the year in Europe, it is a spring fruiter (soon after snowmelt) in some areas of N. America. Insufficient DNA barcode (ITS) sequences in GenBank and UNITE to resolve whether there is taxonomically significant divergence of European and N. American populations.
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