Assessment Notes

Justification

Pseudoplectania melaena is a saprotrophic wood-inhabiting, black and small cup fungus, depending on coarse woody debris – thick dead wood - as a food source. In Europe it grows probably exclusively on wood of white fir. It shows a tendency to grow in natural or semi-natural forests, as the required substrate is absent in many commercial forests. It is an indicator species for semi-natural forests, which are threatened by logging and more and more vanishing. It occurs mostly in spring after snowmelt; the preferred months are March to May with a clear growth peak in April. In total, finds are known in the period from December to May. Its worldwide distribution includes Europe, America and Asia. It is in the Red List of at least five European countries as critically endangered or endangered. The substrate required by P. melaena is absent in most of the managed forests in sufficient quantities, therefore the species is missing in many places and is mainly found in semi-natural forests. Although the latter are often taken out of commercial use, the general decline of the white fir even in natural forests, e.g., in the primeval forest of Boubínský Prales, where P. melaena is currently still quite common, poses a long-term threat.

Unmanaged forests are highly endangered by logging and management changes in many European countries, e.g. in Austria, only 3 % of Austrian forests are virgin forests (including very steep inaccessible ones) and carbonate- and clay-spruce-fir-beech-forests, habitats of occurrence of Pseudoplectania melaena, are endangered biotope types (Essl and Egger 2010).


Given the suspected population decline at a rate of 15-25% over the past three generations (30 years), this species qualifies as Near Threatened (nearly meeting VU A2c+3c+4c).

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Geographic range

Its worldwide distribution is Europe, America (Canada, Mexico, USA) and Asia (China, Japan and Taiwan). In Europe the species follows the natural range of White Fir, but also collections from outside this area or on other fir species are known.

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Population and Trends

Based on GBIF and databases available (see references) 172 subpopulations are known worldwide. The species is very rare. Its habitat of old growth Abies forest is declining throughout its range. It is difficult to accurately estimate the rate of decline worldwide, however we can conservatively suspect a rate of 15-25% over the past three generations (30 years).

Population Trend: decreasing

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Habitat and Ecology

It is a saproxylic mushroom species, depending on dead wood as a food source. In Central Europe it grows probably exclusively on wood of fir (Abies alba). Findings from dissimilar substrates (eg Picea abies) should be compared to the recently described species Pseudoplectania lignicola. In other areas of Europe, finds on Abies nordmanniana and A. holophylla are known. The following substrates are reported from other continents: Abies kawakamii (Taiwan), A. religiosa (Mexico), A. grandis (USA, Canada), and even Thuja plicata (USA).

In Central Europe, P. melaena shows a tendency to grow in natural or semi-natural forests, as the required substrate (large trunks of rotten white fir deadwood in final decay stage) is scarcely present in many commercial forests. In areas with plenty of deadwood, the species can fruit very numerously and is then sometimes among the most common spring fungi. This applies in particular to near-natural montane beech-fir spruce forests like the natural forest Lahnsattel (Lower Austria) or outside of Austria to different areas of the Bohemian Forest. For this reason, P. melaena is sometimes regarded as an indicator species for semi-natural habitats especially for semi-natural forests with large old trees (200+ years old) displaying ecological continuity, which was recently confirmed in the comparison of several near-natural spruce-fir-beech forests. 

At suitable locations it can be found for years, e.g. in the natural forest Lahnsattel (St. Aegyd am Neuwalde) where the species was first observed in 1992, and the latest evidence comes from 2017. 

Pseudoplectania melaena prefers to grow on recumbent, heavily pruned, barked, and overgrown trunks and thicker branches of old trees. Since the dead wood acts as a water reservoir, the species can form fruit bodies even in unfavourable weather conditions.

Phenologically it fructifies mostly in spring from snowmelt; the preferred months in Austria are March to May with a clear growth peak in April. In total, finds are known in the period from December to May.

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Threats

It is in several Red Lists of Central European countries in which it is classified as at least Endangered: Germany, Austria, Slovakia, Switzerland, Czechia. The population shows declining tendencies.

The habitat in North America is highly restricted and had undergone serious decline until protection in the last 20 years.

Habitat trends in Asia are currently insufficiently known.

The substrate required by P. melaena - rotten fir dead wood - is present in most of the managed forests in insufficient quantities, therefore the species is missing in many places or is mainly found in semi-natural forests. Although the latter are often taken out of commercial use, the general decline of the white fir even in natural forests, e.g., in the primeval forest of Boubínský Prales, where P. melaena is currently still quite common, poses a long-term threat.

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Conservation Actions

In managed forests the targeted promotion of white fir and its deadwood, e.g. in the form of old wood islands, could be a great contribution to foster biodiversity and also to the protection of Pseudoplectania melaena. Many other endangered species of fungi rely on fir deadwood and would also benefit from appropriate measures.

In unmanaged forests longer-term inventories of the funga should be executed, in combination with studies on the local stock trend of the white fir, so as to define the most accurate risk situation and appropriate conservation measures.

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Use and Trade

There is no use or trade known.

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Source and Citation

Krisai-Greilhuber, I. 2019. Pseudoplectania melaena. The IUCN Red List of Threatened Species 2019: e.T147440561A148048893. https://dx.doi.org/10.2305/IUCN.UK.2019-2.RLTS.T147440561A148048893.en .Accessed on 3 February 2024

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• Country occurrence