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Amanita torrendii Justo

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Scientific name
Amanita torrendii
Author
Justo
Common names
Torrend's Dry Caesar
Torrendie délicate
Weisser scheidenstäubling
IUCN Specialist Group
Mushroom, Bracket and Puffball
Kingdom
Fungi
Phylum
Basidiomycota
Class
Agaricomycetes
Order
Agaricales
Family
Amanitaceae
Assessment status
Published
Assessment date
2021-07-10
IUCN Red List Category
NT
Assessors
Gonçalves, S.C., Krisai-Greilhuber, I. & Kałucka, I.L.
Reviewers
Dahlberg, A. & Mueller, G.M.

Assessment Notes

The content on this page is fetched from The IUCN Red List of Threatened Species: https://www.iucnredlist.org/species/125433761/125435500

Justification

Amanita torrendii is a typically Mediterranean species that occurs only in the Mediterranean and sub-mediterranean forests and shrublands in sandy soils. It is ectomycorrhizal, primarily with Quercus suber. The conservation status of its most common habitat is reported by the EU Habitat Directive as “Unfavourable-Bad” due to changes in area, structure and function (habitat quality), and future prospects. The population of Q. suber, the species’ main host, is also decreasing. The population size of the species is estimated as 10,000-15,000, and may be declining at a rate approaching or above 10% over a three generation time period (50 years), but there is insufficient evidence to confirm this. Therefore, A. torrendii is precautionarily assessed as Near Threatened under criterion C1.

Taxonomic notes

Amanita torrendii was originally described as Torrendia pulchella by Bresadola (1902). Justo et al. (2010) transferred it to Amanita section Caesareae based on molecular data.

Geographic range

Amanita torrendii has so far been recorded in Spain, Portugal, France, Italy, Greece, and Cyprus, in the Atlas Mountains in Morocco and Algeria, and in Türkiye, a typical distribution around the Mediterranean Sea. The southern limit of distribution is unclear due to a lack of data (e.g. a single historical occurrence in Sierra Leone from 1905 by G. Malecón in GBIF). It is uncertain if the species occurs in other areas of Africa along the Mediterranean.

Population and Trends

In Europe, Amanita torrendii is confined to the Mediterranean region and its most common habitat is Quercus suber (cork oak) forests (Natura 2000 habitat type 9330). The number of known sites for A. torrendii was about 100 in 2015, most in the Iberian Peninsula with only seven in France (including three in Corsica), and four in Italy (of which three are in Sardinia) (Fraiture and Otto 2015). There are currently 210 records of the species in GBIF, approximately 155 are from Spain, and 33 are from Portugal; the number of records from the other countries is much lower (GBIF 2021). While the size of the suitable habitat throughout the region is large, the concentration of the host Q. suber primarily is restricted to the Iberian Peninsula. There are an estimated 1,000 - 1,500 sites throughout its range, each with up to 10 mature individuals per site, giving a total population size of 10,000-15,000.

The conservation status of Q. suber forests is ‘Unfavourable-Bad’ (based on data from Spain and Portugal) due to changes in area, structure and functions (habitat quality), and future prospects (European Environment Agency 2018). This lower status in comparison with the previous assessment period (2007-2012; ‘Unfavourable-Inadequate’) indicates the ongoing decline of this type of habitat in the stronghold of the species. The population of Q. suber, the species’ main host, is also decreasing (Barstow and Harvey-Brown 2017). As a whole, the Mediterranean basin is subject to many pressures (FAO and Plan Bleu 2018). With a growing population and a climate that is expected to become drier and warmer, the pressure on Mediterranean forests is enormous. Direct causes of decline include the conversion of forests to fire-prone shrub communities, outbreaks of pests and pathogens, and increased forest fires. Such pressures mean that the population of A. torrendii may be declining at a rate approaching or above 10% over a three generation time period (50 years; Dahlberg and Mueller 2011), but there is insufficient evidence to confirm this.

Population Trend: decreasing


Habitat and Ecology

Amanita torrendii is a typically Mediterranean species that occurs only in the Mediterranean and sub-mediterranean forests and shrublands in sandy soils. It is ectomycorrhizal with Quercus spp. (especially Q. suber), Pinus spp. (P. pinaster and P. pinea), Cistus spp. (C. monspeliensis and C. salviifolius) and, possibly, also with Castanea sativa. The species occurs in the following NATURA 2000 habitats (codes): 2180, 2270, 9230, 9260, 9330 (Quercus suber forests, the most common habitat), 9340, and 9540 (Dahlberg and Croneborg 2003).

Threats

The species is threatened by land clearance and loss of habitat connectivity, and the modification of semi-natural woodlands management regimes, e.g. overgrazing. Climate change is a growing concern, with increased wildfires, pervasive drought stress and diseases affecting the species’ main host, Quercus suber (Barstow and Harvey-Brown 2017).

Conservation Actions

About half of the known localities are part of the Natura 2000 network and hence thought protected, but appropriate management, e.g. preventing overgrazing, reducing fire frequency, etc. is needed. Protection from habitat changes outside of the Natura 2000 network is also needed. Additional information on distribution and host preference is needed, especially from Africa.

Use and Trade

There is no use/trade in this species.

Source and Citation

Gonçalves, S.C., Krisai-Greilhuber, I. & Kałucka, I.L. 2023. Amanita torrendii. The IUCN Red List of Threatened Species 2023: e.T125433761A125435500. https://dx.doi.org/10.2305/IUCN.UK.2023-1.RLTS.T125433761A125435500.en .Accessed on 2 January 2025

Country occurrence