Boletopsis nothofagi is an ectomycorrhizal fungus of wet forests with Nothofagus in New Zealand. This large, conspicuous and obviously rare fungus is a pored member of the Thelephorales. The number of known locations in New Zealand is two, based on both herbarium collections and observational records. Boletopsis nothofagi was discovered and described after the last review of the New Zealand Threat Classification System (Molloy et al. 2002). Its classification is currently under consideration by the New Zealand Department of Conservation.
The species is assessed as Endangered (EN) under criterion B. The extent of occurrence (B1) is estimated to be 5,000 km2 of available beech forest in an area encompassing the two known sites. The area of occupancy (B2) for the two subpopulations is estimated at 35 km2. The populations meet the subcriteria (a) severely fragmented/few locations, with one subpopulation in the Orongorongo Valley in the Rimutaka Forest Park in North Island and the other at West Bay in the Nelson Lakes National park in South Island. There is also concern over a continuing decline in extent and quality of habitat fulfilling the subcriterion b(iii), as both known sites are open recreational areas under increasing visitor pressure as local populations increase (census increase of 6.4% in the Wellington region in the period 2006-2013). Both populations of B. nothofagi may be considered within the context of the recognised vulnerable Temperate Broadleaf Forest ecoregion of the northern part of New Zealand’s South Island, (http://www.worldwildlife.org/ecoregions/aa0408).
The species are also assessed as Endangered under criterion D as the number of mature individuals is estimated to be less than 250 but higher than 50. This is a conservative estimate based on the number of known genotypes being only two, which is inferred to correspond to a maximum of 10 mature individuals (using a x 5 multiplier to convert to mature individuals (Dahlberg and Mueller 2011)). Recorders state that sightings consist of single clump of fruit-bodies at each site.
The first collection of B. nothofagi was made in 2009 and the species described 2012 (Cooper and Leonard 2012). Only two small subpopulations have been identified, one in the Orongorongo Valley in the Rimutaka Forest Park in North Island and the other at West Bay in the Nelson Lakes National Park in South Island, both at New Zealand. The two subpopulations are separated by the Cook Strait and there is almost no suitable habitat that might be colonised in the area between the currently known location.
There has been extensive surveying by mycologists of the Thelephorales and other mycorrhizal fungi by Cunningham (1958 and 1963) between 1925 and 1945, by McNabb (1968) in the 1960s and by Horak (1971) between 1960 and 1990.New Zealand has a well-documented, if largely undescribed mycota, with national/international mycologists contributing to the PDD fungarium of over 100,000 collections. In addition New Zealand beech forests have come under increasing scrutiny over the last twenty years by annual week-long fungal forays (FUNNZ) attended by between 20-40 people generating over 12,000 observation records, and more recently Naturewatch New Zealand with 4,000 observers contributing 8,000 fungal records to date. From this extensive surveying there are no reports of B. nothofagi other than records from the two locations cited here.
Boletopsis nothofagi is clearly a very rare fungus, It has only been recorded at two locations despite extensive fungal surveying and having are unusually large and conspicuous sporocarps.
The number of mature individuals is estimated to be less than 250 but higher than 50. This is a conservative assessment based on the calculation that the number of known genotypes is only two which is estimated to correspond to a maximum of 10 mature individuals (using a x 5 multiplier to convert to mature individuals (Dahlberg and Mueller, 2011) and also taking unrecorded genotypes of B. nothofagi into account. Recorders state that sightings consist of single clump of fruit-bodies at each site.
There is concern about the decline of the habitat of B. nothofagi, as both known sites are open recreational areas under increasing visitor pressure as local populations increase (census increase of 6.4% in the Wellington region in the period 2006-2013). Both subpopulations of B. nothofagi may be considered within the context of the recognised vulnerable Temperate Broadleaf Forest ecoregion of the northern part of New Zealand’s South Island, (http://www.worldwildlife.org/ecoregions/aa0408).
Population Trend: decreasing