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Lactarius novae-zelandiae McNabb

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Scientific name
Lactarius novae-zelandiae
Author
McNabb
Common names
 
IUCN Specialist Group
Mushroom, Bracket and Puffball
Kingdom
Fungi
Phylum
Basidiomycota
Class
Agaricomycetes
Order
Russulales
Family
Russulaceae
Assessment status
Published
Assessment date
2017-03-10
IUCN Red List Category
EN
IUCN Red List Criteria
B2ab(iii); C2a(i); D
Assessors
Leonard, P.L. & Cooper, J.A.
Reviewers
Dahlberg, A.

Assessment Notes

The content on this page is fetched from The IUCN Red List of Threatened Species: https://www.iucnredlist.org/species/80188416/80188421

Justification

Lactarius novae-zelandiae is an endemic ectomycorrhizal fungus producing large and conspicuous sporocarps only very rarely recorded in wet forests with Southern Beech in New Zealand. The sporocarp appearance of this taxon is striking and the fact that there has been a 47 year gap since it was last sighted strongly underlines the need for an assessment. There has been extensive surveying of the Russulaceae by McNabb (1968) in the 1960s and by Cooper and Leonard between 2005 and 2015. There was only a single record of this easily recognized species between these surveys.  Only two populations where this taxon is present have been identified in New Zealand and the number of known locations is less than five, based on both herbarium collections and observational records. The type locality has been modified by the clearing of forested areas and converted to dairy farming pasture.

Lactarius novae-zelandiae
is classified as Nationally Critical under the New Zealand. Threat Classification System (Molloy et al. 2002) and its classification is currently under review by the New Zealand Department of Conservation, but is likely to remain unchanged.

The species is assessed EN (Endangered) under criteria B and C. It meets the requirements for criterion B as the area of occupancy is estimated to be about 20 km2 along with the subcriterion (a) severely fragmented, with two reported but only one currently known subpopulation near Lower Hutt in North Island and (b(iii))  due to concern over a continuing decline in extent and quality of habitat. It appears that suitable habitat has been lost at the type locality and also the largest site at Karamea where it not has been re-collected since 1971 despite extensive searching over many years. The assessment also meets criteria C and D due to the continuing decline in combination with (a) the number mature individuals estimated to be less than 100 and (b) the number of mature individuals in the largest subpopulation.

Geographic range

Lactarius novae-zelandiae is endemic to New Zealand. Two small subpopulations have been identified, one in Karamea on the west coast of South Island, and a second at Lower Hutt North Island. A collection from Makarora on the edge of the Mount Aspiring National Park in South Island requires assessment to confirm the identity.

Population and Trends

The appearance of the sporocarp of this taxon is striking and the fact that there has been a 47 year gap since it was last sighted strongly imply it to be rare. There has been extensive surveying of the Russulaceae by McNabb (1968 ) in the 1960s and by Cooper and Leonard between 2005 and 2015. There was only a single record of this easily recognized species between these surveys. The fungus has not been seen in Karamea since 1971. New Zealand Fungal Foray participants visited the area during their Westport foray in 2006. Patrick Leonard surveyed the area in 2008 and 2011. No records were made. The total number of known locations where this taxon is recorded is less than five, based on herbarium collections and observational records. 

The estimated number of mature individuals is based on four known unique individuals (genotypes or genets), increased by 100% to allow for undetected individuals, and then using a x 5 multiplier to convert to mature individuals (i.e. fragmented and functionally individual parts of the genotype, or ramtes, see Dahlberg and Mueller 2011). Recorders state that sightings consist of a single group of sporocarps at each site, i.e. single genotypes.

Population Trend: decreasing


Habitat and Ecology

Lactarius novae-zelandiae is an ectomycorrhizal fungus growing  in southern beech (Fuscospora, Lophozonia) forests and associated with Fuscospora truncata growing in relatively mature forests with a sparse understory.

Threats

It is inferred that there has been a decline in the range of this species. The precise type locality is unknown but localized to the area around Karamea. The area has been modified by the clearing of some forested areas and their conversion to dairy farming pasture. The fungus has not been seen in Karamea since 1971. New Zealand Fungal Foray participants visited the area during their Westport foray in 2006. Patrick Leonard surveyed the area in 2008 and 2011. No records were made. It appears that the appropriate habitat at the type locality in Karamea has been much reduced by bushland reclamation for dairy farming, both at Umere Road and at Granite Creek where McNabb made his original collections, however, some suitable habitat may remain in the more inaccessible areas of the Karamea gorge.

The only currently known population near Lower Hutt on North Island lies within a small Park (40 hectares) managed by the local authority and thus receives some protection from development. However, the site is not managed for conservation value, shows signs of low recreational pressure, and is surrounded by private land with recent tree clearing and development. The surrounding area is the main dormitory corridor for Wellington, the New Zealand capital, an area under increasing development pressure. The population lies within 200 metres of a State Highway.

Lactarius novae-zelandiae
is classified as Nationally Critical under the New Zealand Threat Classification System (Molloy et al. 2002) and its classification is currently under review by the New Zealand Department of Conservation, but is likely to remain unchanged.

Conservation Actions

The identification of the sites in the management plans for the Lower Hutt site might protect the species populations from destruction. Protecting mature Fuscospora truncata could possibly aid succession and would at least enhance the chances of the population’s survival. A better understanding of the biology and ecology of the Lactarius novae-zelandiae would clearly be of value. Surveys of other area of mature Fuscospora truncata forests may yet reveal new populations.

Source and Citation

Leonard, P.L. & Cooper, J.A. 2017. Lactarius novae-zelandiae. The IUCN Red List of Threatened Species 2017: e.T80188416A80188421. https://dx.doi.org/10.2305/IUCN.UK.2017-3.RLTS.T80188416A80188421.en .Downloaded on 31 January 2021

Country occurrence