Assessment Notes

Justification

This is likely to be a rare species, but sufficient data are lacking to enable estimation of its distribution, population size and trends. It is therefore assessed as Data Deficient.

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Taxonomic notes

Cortinarius nivalis is one of the truffle-like species in the genus. It is pure white and slimy and readily recognised. The species is sequence barcoded (type sequence) and phylogenetically well classified. This group of fungi has been extensively surveys in New Zealand for at least 50 years.

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Geographic range

This species is a New Zealand endemic associated with beech (Nothofagaceae) limited to the South Island. It is known from four collections from three localities. Cortinarius nivalis is one of the truffle-like species in the genus. It is pure white and slimy and readily recognised.

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Population and Trends

The species is known from four records in three localities over a 50 year period.
 
While it is a distinctive and easily detected species, and has a broad potential range because of the wide-spread mycorrhizal host, it is probably a rare species. The apparent limited distribution and population may be due to the potential loss of dispersal vectors (i.e., native animals) resulting in historic and continued decline. 

While it is assumed to be truly rare, sufficient data are lacking to enable estimates of its distribution, population size and trends.

Population Trend: unknown

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Habitat and Ecology

This truffle-like species is associated with beech forests (Nothofagaceae). Like many New Zealand truffle species, it is visibly noticeable and grows on the surface of the soil layer. These characters are thought to be adaptations to dispersal by animal vectors (the spores do not naturally disperse). Elsewhere truffles are buried, dull-coloured and dispersed by mammals. In New Zealand, without any native mammals (except two species of bat) the role is thought to be filled by ground-dwelling birds or reptiles, bats, insects (e.g., Weta), and snails, which are either extinct (Moa) or in decline. The role in dispersal by introduced mammals is unknown.

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Threats

Historic and continued loss of native spore dispersal animals may be negatively impacting the population. However, the role in dispersal by introduced mammals is unknown.

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Conservation Actions

The potential role of replacement dispersal agents (e.g. introduced rats, possums etc) is unknown. The long-term survival of current populations without active dispersal is unknown.

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Use and Trade

The species is not utilized.

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Source and Citation

Cooper, J.A. 2019. Cortinarius nivalis. The IUCN Red List of Threatened Species 2019: e.T154238045A154238198. https://dx.doi.org/10.2305/IUCN.UK.2019-3.RLTS.T154238045A154238198.en .Accessed on 1 February 2023

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• Country occurrence