Assessment Notes

Justification

Mycena flavovirens is found in a narrow arc in high rainfall forests across the north of North Island from the Urewera National Park in the East to Auckland in the west. It is restricted the dead trunks of tree ferns, primarily Cyathea, but how host species specific it is needs to be confirmed. There have been fourteen records of the species over the past 50 years, including 9 recent postings on iNaturalist, all from four main locations Urewera National Park, Manawhatai, Kamai-Mamaku Forest Park and forest sites around Auckland. The quality of the habitat appears to be declining due to feral animals and weather events.

While this is a conspicuous species occurring on large substrata, it has not been commonly reported supporting a hypothesis of it having a restricted distribution. The estimated number of mature individuals is 1500. It is therefore assessed as Near Threatened, nearly meeting Vulnerable D1.

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Taxonomic notes

A well defined fungus which has been recorded as Insiticia flavovirens by some mycologists.

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Geographic range

Mycena flavovirens is a New Zealand endemic restricted to the North Island. It has been recorded from a narrow band running from Lake Waikaremoana to Auckland. It occurs in big clusters on fallen tree fern trunks and is easily identified from its habit and yellow-green colouration.

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Population and Trends

This fungus is restricted to high rainfall forests that contain tree ferns, notably Cyathea. There have been fourteen records over the past 50 years, including 9 recent postings on iNaturalist. 

This is a conspicuous species occurring on large substrata, yet it has not been commonly reported, supporting a hypothesis of it having a restricted distribution. There are an estimated 100 sites each with 3 colonies (each representing 5 mature individuals) giving the estimated number of mature individuals as 1500.

Population Trend: decreasing

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Habitat and Ecology

Mycena flavovirens is a saprotrophic fungus. This species appears to only grown on fallen tree fern trunks. Stevenson described it from the trunk of Cyathea dealbata and although the majority of subsequent records confirm this association there is one record on C. medullaris and one on Dicksonia sp.

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Threats

The majority of the locations for this species are pockets of native forest that are not necessarily protected within the National Parks and Reserves systems of New Zealand. These areas are subject to land use change and may be under pressure from farming and urban development, particularly the five sites close to Auckland. Predictions of climate change indicate widespread increases in light intensities, temperatures, and the frequency and severity of droughts; all these are known to impact Cyathea spp. and hence substrata for the fungus.

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Conservation Actions

Confirmation the range of the species' host range would assist in understanding how best to conserve it.

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Use and Trade

The species is not utilized.

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Source and Citation

Leonard, P.L., Buchanan, P. & Cooper, J.A. 2019. Mycena flavovirens. The IUCN Red List of Threatened Species 2019: e.T154619291A154622315. https://dx.doi.org/10.2305/IUCN.UK.2019-3.RLTS.T154619291A154622315.en .Accessed on 5 February 2024

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• Country occurrence