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Squamanita schreieri Imbach

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Scientific name
Squamanita schreieri
Author
Imbach
Common names
Gelber Schuppenwulstling
parazitnica Schreierova
IUCN Specialist Group
Mushroom, Bracket and Puffball
Kingdom
Fungi
Phylum
Basidiomycota
Class
Agaricomycetes
Order
Agaricales
Family
Tricholomataceae
Assessment status
Published
Assessment date
2019-03-28
IUCN Red List Category
EN
IUCN Red List Criteria
C2a(i)
Assessors
Kautmanova, I.
Reviewers
Gonçalves, S.C., Brandrud, T.-E. & Saar, I.

Assessment Notes

The content on this page is fetched from The IUCN Red List of Threatened Species: https://www.iucnredlist.org/species/70406908/70406916

Justification

Squamanita schreieri is a rare parasitic fungus on the ectomycorrhizal fungi Amanita solitaria and A. strobliformis. It occurs mainly in alluvial forests, with an overall small population (not expected to exceed 2,000 mature individuals). A decline is the population size is inferred from its habitat degradation (caused by inappropriate management of water levels and the hardwood tree hosts). The number of mature individuals in each subpopulation is assumed to be less than 50, therefore the species is assessed as Endangered under C2a(i).

Taxonomic notes

Squamanita schreieri is only known from continental Europe, except a single record from India. This latter record is considered doubtful and therefore disregarded in this assessment.

Geographic range

This species occurs in temperate to submeridional Europe from France to Ukraine, mainly in local regions in Switzerland and north Italy.

Population and Trends

Only very few localities are known and the species fruits only occasionally. In Switzerland and Hungary, where the species has been recorded more frequently in the past, a strong decline of the species during the last 10 years has been reported. In recent times, it been collected more frequently in Italy (15 records in total, with 10 records from 2008-2018). Other countries report only isolated occasional records: approximately, 20 localities are known from Switzerland, one in Hungary, 4-6 in Germany, one in Austria, two in Slovakia. Considering the overall bad state of the habitat (hardwood alluvial forests) in Europe we can estimate that the decline of the species will continue also in the future, from which a negative trend is inferred in the population.

The species is currently known from 45 localities, that having into account the unknown sites and according to standards (Dahlberg and Mueller 2011), could be considered to equal a maximum of 450 localities in total for this species. Assuming two fungal genotypes per site and the total number of localities to be fewer than 450, the global population size is suspected to be around 1,800 mature individuals.

Population Trend: decreasing


Habitat and Ecology

Squamanita schreieri is known as parasite of two thermophilous Amanita species: (A. strobiliformis and A. solitaria=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 there are also records from xerothermophilous habitats reported from France, Hungary, Greece and Italy.

From Germany and Switzerland it is reported also from mountainous mixed forests with Picea, Pinus and Abies. 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.

Threats

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 logging, replacing 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 various habitats, and even in human influenced ones (parks, roadsides etc.) Squamanita species is rarely recorded in such sites. They seem to be more frequent in undisturbed habitat of various types.

Conservation Actions

The species seems to be mainly occurring in association with NATURA 2000 habitat 91F0, therefore the species is expected to benefit from some protection; however, an appropriate management of the habitat, including maintenance of hardwood tree hosts, would be essential.

The species is included in the Red Lists of four countries, in Hungary it is protected by law. Some of the sites (e.g. in Slovakia) are within protected areas.

Research is needed into the ecology of the species. The Indian collection must be revisited if possible.

Use and Trade

The species is not known to be used.

Source and Citation

Kautmanova, I. 2019. Squamanita schreieri. The IUCN Red List of Threatened Species 2019: e.T70406908A70406916. https://dx.doi.org/10.2305/IUCN.UK.2019-2.RLTS.T70406908A70406916.en .Downloaded on 31 January 2021

Country occurrence