Rhizopogon togasawarensis is hypogeous ectomycorrhizal fungus strictly associated to Japanes Doulas-fir, endemic to Japan. This host tree is a very rare slow growing species consisting of about 2000 trees, with only small and scattered subpopulations and red-list assessed as EN (ENdangered) due to contioniusly declining in popuation size. On the basis of R. togasawarensis (1) strict dependence on it host tree, (2)its population size estimated to be in the same or smaller size than the tree and (3) subjected to te same decline, the fungus is assessed as EN under the C criterion.
Why suggested for a Global Red List Assessment?
This species is the ectomycorrhizal fungus that lives only in symbiosis with the critically endangered Japanese Douglas-fir (Pseudotsuga japonica). Therefore, I think that this species should also be included in the Red List.
Rhizopogon togasawarensis is an endemic fungus only found east Kochi prefecture and the Kii peninsula in Japan where the Japanese Douglas-fir stands grow.
Add extent of occurence
Population and Trends
Rhizopogon togasawarensis is an ectomycorhial fungus only associated with Pseudotsuga japonica. Hence, the population size of R. togasawarensis is fully dependent on presence and the population status and trend of P. japonica. The host tree is endemic to Japan and a very rare species, with only small and scattered subpopulations of very slow growing trees and the total population consists of approximately 2000 mature trees. The total population of the tree is considered to be continuously declining and is redlisted as EN (Katsuki, T., Luscombe, D & Farjon, A. 2013). The population size and trend of R. togasawarensis is estimated to be in the range of, or even smaller than of the tree host.
Some more about the C and B criteria.
Population Trend: Decreasing
Habitat and Ecology
This species is the ectomycorrhizal fungus that lives only in symbiosis with the critically endangered Japanese Douglas-fir. Therefore, the fungus is only present in forests dominated by Japanese Douglas-fir. In addition, the fungus is hypocarpogean which produces fruiting bodies in the soil and the dispersal of its spores is dependent on animals.
Add tree not cultuvated and no ex situ conservation. The fungus strictly dependent on te tree in the wild.
The threat of this species is the same as the threat of endangered Japanese Douglas-fir, as this species cannot survive without its host.
Add host declining due to forestry operations (ref 2013.
Scale Unknown/UnrecordedIntentional use: subsistence/small scale (species being assessed is the target) [harvest]
As this species has only recently been discovered, there has been no conservation action done on it. On the other hand, some areas of its habitat are protected for its host, Japanese Douglas-fir.
Add something about…..We cannot be fully sure that the species is only associated with Japanese Doglas Fir.