Hymenopellis atroruginosa is a distinctive species, easy to identify in the field. Distribution is limited to wet montane forests. The habitat is largely unmanaged and undergoing change due to feral animals.
There have only ever been 4 functional individuals of this fungus found from two sites. Using the Dahlberg & Mueller (2011) methodology we estimate that, allowing for previously known and as yet undiscovered sites, there might be up to 5 sites and a population of up to 50 mature individuals. This takes in to account the very steep and inaccessible terrain of a substantial part of the Tchamba Valley and Mont Bouo.
This species is assessed as “ critically endangered” on the basis of criteria B1, B2a and B2b with only two known sites and a potential of 5 sites in an endangered ecosystem and D1 on account of the a very small estimated population of less than 50 mature individuals.
Pileus: shallow convex with an umbo; 40 - 55 mm diameter;reticulate, with raised radial striae and cross striae, glabrous umbo; pale silver grey ground with blue black striae overlay; margin acute.
Stipe: cylindrical; 60- 120 × 5–25 mm; glabrous to pruinose; pale silver grey.
Gills: adnexed to free; moderately spaced, white; lamellulae in one series.
Spore print: white.
Spores: globose; 14 - 15 × 12.5 - 14.5 µm, Q = 1 = 1.1; with a large vacuole.
Habitat: in leaf litter in montane forest above 800 M.
Notes: this Hymenopellis does not readily fit any of the species described by Petersen and Hughes in their world monograph on the genus. They do not record any species for New Caledonia. The cap is reminiscent of Bolbitius reticulatus, but this is a new Hymenopellis.
There are at least two endemic Hymenopellis species in New Caledonia that are found in motane and humid forests. This one has been published and is readily recognized because of its dark almost black reticulate cap and contrasting pale stem. It was described from the high mountain forest of Mont Bouo near Noumea. In the past decade the SMNC have visited most of the remaining areas of montane forests and it has not been seen again. We may reasonably assume that this fungus species is naturally rare.
There has been no system of formally recording fungi in New Caledonia in the past. Le Rat made many fungal collections between 1900 and 1910 some of which were then described and published by Patouillard. Roger Heim published some further species in the 1930s. Horak visited New Caledonia during the 1970s and published several papers during that decade. It was not until 2009 (?) that a more formal system was established to monitor fungi, following Marc Ducousso’s formation of the Societe Mycologique du Nouvelle Caledonie. Since then some 25,000 fungi have been photographed by members of the SMNC and these form the basis of current records. There was also a formal survey of dry sclerophyll forests in 2010 directed by Ducousso which sets a base line for that forest type. In 2001 a website was established by Endemia NC to provide a record of all New Caledonia’s wildlife. In its early years it concentrated on birds and NC’s rich plant flora. It has recently (2018) started to accumulate fungal records.
The paucity of data might suggest that all NC fungi should be considered as data deficient. However for well defined species and particularly for those which can be reliably identified from photographic evidence we can claim relatively good information on current distributions but not on population trends. Hymenopellis atroruginosus remains known from two collections in the Tchamba Valley in North Province and at Mt Bouo in South Province.
In humid and montane forest remnants on Grand Terre.
Only a very small portion of the original forest cover of New Caledonia remains. Clearing in the past for timber and to create grazing and agricultural land have destroyed much of the forest cover. Wild fires and open cast mining have also accounted for extensive losses. There is however virtually no active management to encourage regeneration or to discourage invasive species.
Pigs are very numerous throughout New Caledonia’s forests, even in montane forests. Thought to be the legacy of Captain Cook’s visit in 1774. The gift of 12 Rusa deer to the Governor of New Caledonia in 1862 has resulted a large current population; estimates range from 400,000 to 1,000,000. There are also established populations of feral cattle and horses in parts of New Caledonia but they are not thought to affect the Mt Buou forest. All these introduced species cause damage to native forests, in particular through selective grazing which impedes regeneration, changes species composition and through nutrient enrichment and digging (pigs) and compaction (horses and cattle).
Pigs are the main pest species in the Tchamba Valley and at Mont Buou and probably specifically target fungal species. There is no known published research on the effect of pigs on the genus Hymenopellis.
Recognition of the role of fungi in the ecology of forests by including references in management plans would be helpful. More effective control of feral animals would be beneficial.
Research on the effects of feral animals on vegetation is ongoing but needs to be extended to cover fungal populations.
Atlas de la Nouvelle Caledonie (1983). Auteur? Imprimerie H. Dridé
Global Biodiversity Information Facility: gbif.org
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Eyssartier, G. et Ducousso, M. (2014). Hymenopellis atroruginosa sp. nov. un nouveau champignon xeruloide de Nouvelle-Caledonie. Bulletin de la Société Mycologique de France. 130(4):267-273
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