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Hydnellum gracilipes (P. Karst.) P. Karst.

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Scientific name
Hydnellum gracilipes
Author
(P. Karst.) P. Karst.
Common names
 
IUCN Specialist Group
Mushroom, Bracket and Puffball
Kingdom
Fungi
Phylum
Basidiomycota
Class
Agaricomycetes
Order
Thelephorales
Family
Bankeraceae
Assessment status
Published
Assessment date
2015-04-27
IUCN Red List Category
VU
IUCN Red List Criteria
A2c+3c+4c
Assessors
Brandrud, T.-E.
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/76170958/76170972

Justification

Hydnellum gracilipes is a strange, hydnoid fungus with a reduced, thin stipe, and a thin pileus normally attached to the underside of old, often burned logs (Køljalg and Renvall 2000). The species forms mycorrhiza with Pinus sylvestris, and is confined to old-growth, often more or less pristine, sandy pine forests. H. gracilipes is regarded as an indicator species of old-growth forest conditions, with downed logs and influence from forest fires, and is therefore vulnerable to (clear-cutting) forestry, fragmentation of old-growth forest patches, and a nowadays a reduced frequency of fires. It suffers from decline in the proportion of old-growth forests with intact, natural disturbance regimes in all parts of its distributional area. The proportion of forested areas with clear-cuts is decreasing with approx. 1% per year nowadays in Sweden and Finland. Furthermore, sandy pine forests are regionally declining, due to (i) change in land-use/urbanization, and (ii) eutrophication/increased N-loads ((Brandrud and Bendiksen 2014). Altogether, a population-loss of >30% during the past 50 years (three generations) and this is predicted to continue into the future.

The species seems to be almost confined to the Fennoscandian, boreal Scots Pine forest, and is Red-listed in Norway, Sweden and Finland.

Geographic range

With present knowledge, this species seems to be primarily restricted to North Europe, almost confined to Fennoscandia-West Russia. The main subpopulations are in the northern boreal regions. The species was also recently reported from the Caledonian pine forests of Scotland (one find, confirmed by molecular identification). Occurrence in the coniferous regions of Central Europe is not well documented, but one record is indicated from Austria, and one from Slovenia.

Population and Trends

Hydnellum gracilipes is currently know from ca. 200 localities. In Norway the species is recorded from 32 localities, half of them at Pasvik, Finnmark, NE Norway. In Sweden, the species is known from 120 localities (mainly in N Sweden), probably with a similar occurrence in Finland. It is known from one site in Russia, Leningrad region, and could have a wider distribution in the sandy pine forests also in this region, being adjacent to the core area of Sweden-Finland. The real number may be 10x higher and are estimated to approx. 2,000, inferring a maximum of 40,000 mature individuals. The species has (only) small subpopulations and is severely fragmented.

The species and its habitat (old-growth, sandy pine forests) are probably decreasing by more than 30% in three generations (50 years; see Dahlberg and Mueller 2011). Forests where it occurs are primarily threatened by clearcutting and possibly it is also negatively affected by nitrogen fertilization of forests (Brandrud and Bendiksen 2014). There is furthermore a loss of sandy pine forest habitat in many areas due to expanding urbanization, road construction, etc. The species seems to be lacking in younger forests after clearcutting, probably due to the lack of downed logs which the species needs as attachment of the basidiocarps. It may also be due to its slow population dynamics, surviving natural disturbances like forest fires on surviving, old pines. Historically, boreal forest fires were low-intense with a high degree of tree survival, and hence with a high likeliness for mycelia of ectomycorrhizal fungi to be very old. 

Population Trend: decreasing


Habitat and Ecology

Hydnellum gracilipes forms mycorrhiza with Scots Pine (Pinus sylvestris), in dry, preferentially lichen-dominated, richer, continental sandy pine forests, sometimes also in richer low-herb(-calcareous) pine forests, and in rocky pine sites with shallow soils, possibly with small deposits of sandy moraine ((Køljalg and Renvall 2000, Brandrud and Bendiksen 2014). The species furthermore regularly occur in old-growth to pristine, often forest-fire influenced forest sites. The mycelia of the fungus is considered to potentially be as old as the pines, or older. Probably, the mycelia of the fungus survive forest fires if the Scots Pine trees they are associated with do.

Threats

It is primarily threatened by clear-cutting of old-growth pine forests, nitrogen fertilization of forests, and measures to prevent forest fires (Brandrud and Bendiksen 2014).

Conservation Actions

To prevent decline and fragmentation of the old-growth, dead- wood-rich sandy pine forests with natural dynamics it is important to set aside Scots Pine forest reserves, preferentially larger, continuous areas, in regions where the species have good populations. In these forests, natural or prescribed burning should be considered to maintain desired forest dynamics.

Research needed: Since the species is rather well hidden (under logs) and little known until recently (almost all Fennoscandian finds are after 2000), more mapping/monitoring is needed, especially in new potential areas such as northern boreal sandy pine forests in Russia. The species supposed slow population dynamics, with probably very old genets, and re-vitalization by forests fires should also be studied/documented further.

Use and Trade

The species is not known to be used.

Source and Citation

Brandrud, T.-E. 2015. Hydnellum gracilipes. The IUCN Red List of Threatened Species 2015: e.T76170958A76170972. https://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T76170958A76170972.en .Downloaded on 31 January 2021

Country occurrence