This species is the ectomycorrhizal fungus that lives only in symbiosis with the endangered Pinus amamiana. Therefore, I think that this species should also be included in the Red List.

This species is found only in the Pinus amamiana stands. Pinus amamiana is only present onYakushima and Tanegashima Islands, Kagoshima Prefecture in Japan.

This species is only sympatric with Pinus amamiana, so the population size is also dependent on the tree. The host population is approximately 2300 (Yakushima: 2000, Tanegashima: 300) individuals and is decreasing.

Motivate criteria. Tree population is declining, pine wood nematod is causing mortality, past timber exploited, very rare in cultivation. Maybe present in Japanese gardens (perhaps also this R. taxon). 2000 of the 2300 trees protected.

The same assessemnt as the previous R.

This species ectomycorrhizal fungus is only recorde in symbiosis with the tree Pinus amamiana. Therefore, the fungus is only present in forests dominated by P. amamiana. In addition, the fungus is hypocarpogean which produces fruiting bodies in the soil and the dispersal of its spores is dependent on animals.

Develop the text.

The threat of this species is the same as the threat of endangered tree Pinus amamiana, as this species cannot survive without its host. Pinus amamiana is globally redlisted under criteria A and B as EN (Katsuki, T. & Farjon, A. 2013). This rare species has an area of occupancy (AOO) of less than 100 km²; the total population size amounts to fewer than 3,000 trees (ca. 2,000 on Yakushima) and is declining. These trees were formerly exploited for timber and regeneration is slow due to exposed conditions. Pine Wood Nematodes accidentally introduced from the U.S.A. have caused increased mortality among seedlings and saplings according to information obtained by Tetsukazu Yahara (pers. comm.) of the IUCN SSC Japanese Plant Specialist Group in 1999.

This species meets the thresholds for Endangered under both criteria B and C. Even though exploitation has ceased, the more recent infestation with pine nematodes continues to cause serious population decline. The use of the A-critera does not qualify for EN for the truffle.

As this species has only recently been discovered, there has been no conservation action done on it. On the other hand, All areas where Pinus amamiana, the host of this species, is present are protected. NPOs are active on Yakushima and Tanegashima with the aim of conserving P. amamiana.

Same comment as for the other Rhizopogon, if associated to other trees.

Katsuki, T. & Farjon, A. 2013. Pinus amamiana. The IUCN Red List of Threatened Species 2013: e.T34180A2849479. https://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T34180A2849479.en. Downloaded on 22 April 2021.