This species appears to have a discontinuous spread, with the majority of records coming from areas with Myrceugenia exsucca in central Patagonia. There is evidence that the species may also occur in Tierra del Fuego on different hosts, but genetic work is needed on individuals occurring there to confirm that it is conspecific and those individuals are precautionarily not considered in this assessment. The overall population size is fairly small (c.16,020 - 40,050), but this comes with some uncertainty; and more work is needed to confirm the subpopulation structure in the northern part of its range. The likely population size is closer to the low end of this estimate. Thus, the species is assessed as Near Threatened under criterion C2a(ii).
The species is characterized by the crustaceous white corticioid basidiome, growing almost specifically on bark of living Myrceugenia exsucca. Microscopically it is characterized by the encrusted dendrophyses and cylindric and smooth basidiospores with a median characteristic constriction (Greslebin and Rajchenberg 1998).
Dendrothele pitrae is a rare corticioid fungi living on bark of living trees, only known from the temperate zone of Argentina.
It is almost confined to Myrceugenia exsucca which is restricted in distribution to Argentina and Chile.
Dendrothele pitrae has not been found in surveys in neighboring Chilean forests (Gorjón & Hallenberg 2012).
Host presents a decreasing population trend frequently altered by the action of man and by the construction of recreational areas.
The ongoing decline of its host tree of in combination with its fragmentation and rareness, considering undiscovered sites, results in it being assessed as Vulnerable (VU) under the criteria:
A: VU A4 c this criterion applies because the decline of its host is expected to drive a reduction in population size in a period of 3 generations (100 years)
B: EN B1 B2 a b (i, ii, iii) this criteria applies because area of occupancy (estimated on the base of AOO of its host), is less than 500 km2.
C: VU C1 this criterion applies because the number of mature individuals is estimated as <10,000 and the number of mature individuals in each subpopulation is estimated <250
D: VU D D2 This criteria apply on the basis of an inferred population with less than 1000 individuals and a AAO <20 km2.
E: NT Probability of extinction is estimated as <10% in the next 100 years
This species is known from few localities in Argentina: Chubut, Lago Puelo (SPG 2789); Chubut, Cushamen, Epuyen (AG 1084, holotype); Neuquén, Nahuel Huapi National Park, Puerto Blest (SPG 2906); Río Negro, El Bolsón (MR 11220). Its main host (Myrceugenia exsucca) is associated with water courses, temporary flooded lands and marsh areas. Stands of M. exsucca in Chubut were surveyed and the species was recorded in 75 % of them. It has been searched for but not found in Chile (Gorjón and Hallenberg 2012). There is a record in one locality in Tierra del Fuego (Estancia Moat, Depto. Ushuaia, Argentina), growing on Berberis ilicifolia and Maytenus magellanica, but these records are not included within the assessment pending genetic confirmation.
The species is known from less than 10 collections. The population is suspected to be decreasing as the host tree is likely in decline. The species has been found at 75% of surveyed sites in the northern part of its range, but only on a limited percentage of trees at each site. Based on the potential range of the main host in the northern part of the species’ range and assuming 2 mature individuals per host tree, the overall population size in the northern part of its range could be in the range c.16,020 - 40,050 mature individuals. The small isolated subpopulation in Tierra del Fuego would not significantly increase this estimate.
Population Trend: Decreasing
This species grows on the bark of living Myrceugenia exsucca. The records from Tierra del Fuego wer found on Berberis ilicifolia and Maytenus magellanica.
The species’ host, Myrceugenia exsucca, is a very hydrophilic species, occurring next to rivers, lakes and estuaries, especially in temporarily flooded lands, in sites frequently altered by the action of man and by the construction of recreational areas, campsites, jetty areas etc. Therefore, this presents some degrees of vulnerability and threat. Any increase in drought frequency due to climate change would significantly impact the species’ host. Fires can also pose a threat.
Protection of the species’ host is important for this species’ conservation as would wider-spread protection of habitat in the region.
A fuller understanding of the species’ geographic distribution needs to be assessed, especially in Chile, as well as knowledge of factors affecting its limited distribution within the host range. An assessment of the genetics of the subpopulation in Tierra del Fuego is important to confirm its presence within this species, and to help to define the limits of its range. Further research into the life history of the species would be useful, in order to assess dispersal ability and the connectivity of different habitat patches in the northern part of the range.
There is no use/trade of this species.
Greslebin, A and Rajchenberg, M. 1998. Corticioid Aphyllophorales (Basidiomycotina) from the Patagonian Andes forests of Argentina. 3. The genus Dendrothele. Mycotaxon, 67: 469–486.
Gorjon, S. P., and Hallenberg, N. (2012). Some new species and new records of corticioid fungi (Basidiomycota) from the Brazilian Amazon. Phytotaxa, 67(1), 38-54.