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.
Squamanita schreieri is rare parasitic fungus on the ectomycorrhizal fungi Amanita solitaria and A. strobliformis in alluvial forests as well as in coniferous forest in mountain areas. It has an overall small population and is declining.
VU to EN (D, D1) Number of mature individuals is less than 1000, probably less than 250. Number of known localities in the last 10 years is around 20 with 1-2 individuals per site. Assessed for 10 years period proposed by Dahlberg & Mueller (2011) for fungi on short-lived discrete substrata, likely to have short generation length.
EN (B2a+bii+biii) AOO is less than 500 km2 and population is severely fragmented with observed and estimated continuing decline of area of occupancy and quality of habitat.
CR (C2ai) Small declining population with number of mature individuals in each subpopulation less than 50.
Squamanita schreieri is extremely rare parasitic species, friuting on dead basidiomata of Amanita strobiliformis and A. echinocephala. Except one record from India known only from continental Europe. Probably less than 50 records worldwide, of that only up to 15 recent (2012 - 2018).
Most of the records are from alluvian lowland forests and dry mediterranean growths. Numerous collecttions: Italy 15, Germany 4 - 6, France 5, Switzerland 3 (probably same locality). Only single records are reported from other countries. Isolated record from Kashmir in India at altitude 2700 m could be considered doubtful.
Only very few localities are known and the species fruits only occasionally. Switzerland and Hungary, where the species has been recorded more frequently at past reported strong decline of the species during the last 10 years. Only in Italy it has been collected more frequently, 2008 - 2018 - 10 records. Other countries report only isolated occasional records.
Considering overall bad state of the habitat (hardwood alluvial forests) in Europe we can estimate that decline of the species will continue also in future. The species is redlisted in 4 countries, in Hungary it is protected by law.
Some of the sites (e.g. in Slovakia) are within protected areas.
Estimated number of mature individuals is less than 1000, probably less than 250. Number of known localities in the last 10 years is around 20 with 1-2 individuals per site.
Though the EOO is more than 20 000km2, AOO is less than 500 km2 and population is severely fragmented with observed and estimated continuing decline.
Population Trend: Uncertain
Squamanita schreieri is known as parasite of two Amanita species (A. strobiliformis and A. echinocephala) which are themselves considered rare. Both Amanita species are xerothermophilous, mycorrhizal with various deciduous, mostly hardwood trees (Quercus, Fagus, Tillia a.o.). This is in contrast with the preferred habitat of S. schreieri, which is alluvial forests. Despite the lack of data this leads to the conclusion that S. schreieri probably needs hardwood alluvial forest (Querco-Ulmetum), corresponding with NATURA 2000 habitat 91F0 - Riparian mixed forests of Quercus robur, Ulmus laevis and Ulmus minor, Fraxinus excelsior or Fraxinus angustifolia, along the great rivers (Ulmenion minoris). However also records from xerothermohilous habitats are reported from France, Hungary, greece and Italy, if the wether is unusually wet and warm (Cupressus sempervirens, Cedrus atlantica, . From Germany and Switzerland it is reported also from mountainous Picea, Pinus and Abies forests. Atitude from 50 to 500 m (in India 2700 m).
In Slovakia A. strobiliformis frequently occurs in alluvial forests (hardwood and softwood) but Squamanita has been observed only in hardwood sites. Since 2007 no recent record of Squamanita, despite intensive search.
The current state of NATURA 2000 habitat 91F0 - Riparian mixed forests of Quercus robur, Ulmus laevis and Ulmus minor, Fraxinus excelsior or Fraxinus angustifolia, along the great rivers (Ulmenion minoris) is assessed as ‘unfavourable-bad’ in most European countries, reflecting the ’bad’ status o f the habitat area and structure and function. The functions of the habitat are closely linked to the flood regime of the river. This habitat is seriously threatened due to management of water levels and the regulation of water courses with very few of Europe’s larger rivers having a natural flood regime. (Eionet Forum, Article 17 - Reporting under Habitats Directive).
Moreover, this habitat is threatened by invasive logging, replanting of the native hardwood trees by rapidly growing cultivars and non-native species, inappropriate forestry techniques, resulting in land degradation and spreading of invasive plant species and water pollution.
Though Amanita strobiliformis and A. echinocephala occurs in varoius habitats, and even in human influenced ones (parks, roadsides etc.) Squamanita species has never been recorded in such sites. They probably require undisturbed habitat of various types.
Research needed in ecology of the species. Revision of Indian collection if possible.
The species is not known to be used.
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