A rarely collected wood-inhabiting, fungus that is confined to ash (Fraxinus excelsior). Ash is seriously declining due to ash decline caused by the introduced invasive pathogen Hymenoschyphus fraxinea that is sweeping across Europe. The disease affects both young and old ash trees. Ash appears to have very limited resistance to ash decline, is rapidly declining throughout Europe and is evaluated to critically effect all species confined to ash.
Preliminary global red-list assessment: NT A3bc+4bc; B2ab;D1 (Near Threatened)
Motivation. Evaluation period is critical. Here we have used 20 years (e.g. 3 generations = 20 years; if confined to coarse woody debris and potentially more long-lived mycelia, 30 years evaluation period could be motivated; and if confined to fine woody debris and potentially more short-lived mycelia, 10 years evaluation period could be motivated). Ash has neither been globally red-listed nor been red-list assessed for Europe. However, nationally it is e.g. in Sweden it was classified as VU (A3ce+4ce) in 2010 and is suggested to upgraded to EN (A3ce+4ce) in 2015.
Population reduction is suspected to be met in the future based on the area of occupancy and decline in habitat quality (A, B and C criterion) . The decline will depend on the length of the evaluations period. There is also an uncertainty, depending on the species is endophytic/saprotrophic as the wood of appropriate ash substrate may increase in a short-term perspective (if saprotrophic).
Area of occupancy (AOO) less than 500 km2 even considering unrecorded localities. Number of known locations less than five.
Total number of mature individuals (including estimate of unknowns) very difficult to estimate.
It is probably close to VU in criteria A, close to EN in criteria B (as it not fully fulfill criterion B for EN or VU it falls down to NT) and close to VU in criterion D, why we suggest NT.
Originally also motivated by “Cannon & Minter (2013), suggested this fungus globally as critically endangered”
EUROPE: France, Spain, UK. These records are probably within the natural distribution of the species. Records up to about 200 m above sea level, but may occur higher.
Three records (specimens, databases and bibliographic sources combined, excluding duplicates) from at least 1976 to 2011, with observations in April, May and October.
There are very few records of this species even though it belongs in a group of ascomycetes generally rather well covered by field mycologists. It appears to be extremely rare and is known from only three localities. Ash, the only associated plant on which it has been observed to grow is seriously threatened by a new dieback disease which is sweeping across Europe.
Estimated extent of occurrence [calculated using http://geocat.kew.org]. About 0·3 million km2 (Europe: 0·3 million km2). Estimated area of occupancy [calculated using http://geocat.kew.org]. About 12 km2.
Population Trend: Decreasing
Stromata and ascomata occur on dead and decorticated wood of Fraxinus excelsior, suggesting the fungus is a saprobe. Nothing is known about interactions between this species and organisms other than plants. This species may be an endophyte.
At present the plant with which it is associated, Fraxinus excelsior, is a common and widespread species, but ash dieback caused by Hymenoscyphus pseudoalbidus Queloz, Grünig, Berndt, T. Kowalski, T.N. Sieber & Holdenr. (better known by the synonym Chalara fraxinea T. Kowalski) is likely to result in significant loss of habitat as it spreads across Europe. Currently, Fraxinus excelsior L. has not yet been assessed for the UICN Red List.
Previously, Cannon & Minter (2013), using IUCN categories and criteria, evaluated this fungus globally as critically endangered.
Well documented species. Area of occupancy less than 500 km2. Number of locations less than five. Number of mature individual less than 250. Population reduction suspected to be met in the future based on the area of occupancy. However, criterion A4 falls because there is no certainty of the generation time and increase of substrate short-term. It is close to Endangered both in criteria A and B so we suggest Near Threatened.
For in situ conservation, no actions exist. For ex situ conservation, no sequences were found in a search of the NCBI, GenBank database [www.ncbi.nlm.nih.gov]; no living strains of this species were found in a search of the Culture Collection Information Worldwide on-line catalogue [www.wfcc.info/ccinfo/home].
CANNON, P.F. & MINTER, D.W. Nemania gwyneddii. IMI Descriptions of Fungi and Bacteria No. 1946 (2013).
PETRINI, L.E. & MÜLLER, E. Haupt- und nebenfruchtformen Europäischer Hypoxylon-Arten (Xylariaceae, Sphaeriales) und verwandter pilze. Mycologia Helvetica 1: 501-627 (1986).
POUZAR, Z. Reassessment of Hypoxylon serpens - complex 1. Česká Mykologie 39 (1): 15-25 (1985).
WHALLEY, A.J.S., EDWARDS, R.L. & FRANCIS, S.M. Hypoxylon gwyneddii sp.nov. from Wales. Transactions of the British Mycological Society 81 (2): 389-392 (1983).
Also: Asturnatura.com [www.asturnatura.com/especie/nemania-gwyneddii.html]