Ectomycorrhizal fungus of wet forests with Southern Beech in New Zealand. The macroscopic 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 recognised species between these surveys. The number of known locations where this taxon is present in New Zealand is less than 5, based on both herbarium collections and observational records.
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 (Dahlberg & Mueller 2011) as Endangered under B. Geographic Range for B2 Area of occupancy (NZ 18 km2) along with meeting the subcriteria (a) Severely fragmented, with one currently known population near Lower Hutt in North Island. It has not been re-collected at the Type locality Karamea, South Island, despite extensive searching over many years. A collection from Makarora on the edge of the Mount Aspiring National Park in South Island requires assessment to confirm the identity. There is also concern that over the (iii) quality of the habitat, as it appears that suitable habitat has been lost at the largest site at Karamea.
The species is assessed as Critically Endangered under C Small population size and decline with the
estimated number mature individuals about 40, based on 4 known individuals, increased by 100% to allow for undetected individuals, and then using a x 5 multiplier to convert to mature individuals. Recorders state that sightings consist of a single group of fruit-bodies at each site.
Two small populations have been identified:one in Karamea on the west coast of South Island, and a second at Lower Hutt North Island.
It may be 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.
Population Trend: Decreasing
Ectomycorrhizal in southern beech (Fuscospora, Lophozonia) forests and associated with Fuscospora truncata growing in relatively mature forest with a sparse understorey.
The Lower Hutt site 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 State Highway 2.
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 identification of the sites in the management plans for the Lower Hutt site might protect the species from direct and destruction. Protecting mature Fuscospora truncata could possibly aid succession and would at least enhance the chances of the population’s survival.
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.
Dahlberg A, Mueller GM, 2011. Applying IUCN red-listing criteria for assessing and reporting on the conservation status of fungal species. Fungal Ecology 4: 147-162.
McNabb R. (1968). The Russulacea of New Zealand. New Zealand Journal of Botany 6 (2), 137 – 176.
Molloy J, et alia, 2002. Classifying species according to threat of extinction. Threatened Species occasional publication 22, Department of Conservation, New Zealand.
NZ Fungi 2 (2015). http://nzfungi.landcareresearch.co.nz/html/mycology.asp