The replacement of old olive groves by new plantation hints at criterion A (clearly there is an ongoing decline of its substrate)., but with so few known sites it looks it might well just be a rare species or under recorded? We need to get more information about search efforts for the species across its distribution range to be able to estimate population size.
Not enough data to establish population size.
Obligate synonyms of this taxon are Cerocorticium lusitanicum (Torrend) Jülich & Stalpers and Radulomyces lusitanicus (Torrend) Hjortstam (MycoBank, 2023).
Why suggested for a Global Red List Assessment?
With the replacement of old olive groves by new plantations, it is becoming difficult to find Adustomyces lusitanicus (Torrend) Jülich, a decomposer species known from Portugal, Spain, France, Greece and Morocco and always found on the dead wood of old olive trunks.
For many years, the species was only known from Portugal, where sporadic collections were recorded, and from Morocco. Later, its distribution was extended to Spain and Greece (Melo, 1992). According to GBIF, it is also found in France (two records, one in Corsica).
Population and Trends
The species is known from approximately XX sites:
GBIF: 1 in Greece (Corfu), 2 in Morocco, 2 in France, 2 in Spain ;
For Portugal: 6-7 documented in Melo (1992) not sure if there are two sites in Lisboa, Lumiar or if they correspond to the same one) + 1 site in Santarém from GBIF
Habitat and Ecology
Adustomyces lusitanicus is a poor decomposer, causing a white rot on old stumps or dead parts of old trunks of living trees, almost always Olea europea.
Mediterranean-type Shrubby Vegetation
Further research is needed to ascertain the population size of the species.