Assessment Notes

Justification

There are currently only a limited number of known subpopulations of this species over a rather large geographic area in South America. The type locality is now possibly extinct, but further subpopulations potentially are yet to be discovered. The overall population size is estimated to be fewer than 1,000 mature individuals, and this species is listed as Vulnerable under criterion D1.

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Geographic range

Nothojafnea thaxteri is recorded from Nothofagus forests of northern and central Patagonia, from region VII (Maule) in the north to Chubut in the south. It is currently known from five sites, although it may now be extinct around Concepcion (which is the type locality). Further survey effort may find this species at further sites.

Since the distribution range of ectomycorrhizal species associated with Nothofagaceae are usually confined within continents, mention of the species from Tasmania (Gates et al. 2009) may be a misidentification of the Australian species Nothojafnea cryptotricha, or another, potentially undescribed species. Further genetic research into these Tasmanian specimens is required to decipher their status (G. Gates pers. comm. 2020). An additional voucher specimen from Ecuador (NYBG, Mycology Collections Portal 2019) was actually originally described as cf. Nothojafnea thaxteri, and it is not believed to truly represent this species.

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Population and Trends

Until recently, Nothojafnea thaxteri was only known from a limited number of records, including the type specimen in Chile (Biobío, 1905) and a recent collection from Argentina (Chubut, 2014), while additional literature records from Argentina (Neuquén, Río Negro, Tierra del Fuego) require further investigation. Recently, in 2019, various new subpopulations were found in northern Patagonia (Araucania and Maule) indicating that the species was previously overlooked. In addition to the type locality (where it is now possibly extinct), there are currently four known, georeferenced sites over a rather large geographic area. However, the species is rare at observed sites, and the number of mature individuals per subpopulation is estimated at only 10 mature individuals. Taking this into account, as well as the amount of suitable Nothofagus habitat in the region, it is highly unlikely that there are over 100 subpopulations of this species, and so the total population size is likely to be fewer than 1,000 mature individuals. Given that there have been these recent discoveries, and there are further literature records that require future re-investigation in the field, we cannot say with any confidence that there are <25 subpopulations, and so a tentative population size of 250-999 mature individuals is used in this assessment.

Population Trend: stable

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Habitat and Ecology

Nothojafnea thaxteri is an ectomycorrhizal species fruiting on soil, sometimes abundantly (up to 30 fruiting bodies). It is associated with Nothofagus forests, in particular those including N. dombeyi. This species seems to fruit more in the spring rather than the fall.

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Threats

This species is associated with a reduced and fragmented Nothofagus forest (due to agriculture and fires), particularly in the northern part of its distribution. Deforestation and forest fires due to drought and climate change are a growing threat. Urbanisation potentially played a role in the possible disappearance of the Concepcion subpopulation.

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Conservation Actions

Various localities lie within protected areas at the regional or the national level (Los Alerces National Park, Los Ruiles National Reserve, Huerquehue National Park). Increasing awareness of this species within these sites would be beneficial. One of the reasons why this species is of interest for conservation action is that because it is one of only two species known from its genus (the other of which is in Australasia) with a basal phylogenetic placement in a family of truffles (but it is apothecial). Further research is needed about the biology (fruiting patterns, dispersal) and the ecology (habitat requirement, host specificity and interactions) of the species, as well as the biogeography of the genus Nothojafnea in the southern hemisphere. Recent collections indicate that more populations probably exist, although mention of the species from Tasmania needs further investigation to delimit the species based on morphology and molecular data.

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Use and Trade

No use or trade is currently known for this species.

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Source and Citation

Truong, C., Monroy Guzmán, C., Kuhar, F. & Pfister, D. 2020. Nothojafnea thaxteri. The IUCN Red List of Threatened Species 2020: e.T163618381A163626053. https://dx.doi.org/10.2305/IUCN.UK.2020-3.RLTS.T163618381A163626053.en .Accessed on 8 February 2024

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• Country occurrence