The estimated number of mature individuals is 150.
Xerocomellus griseoolivaceus is known with certainty from the type locality in the north of North island New Zealand.
Why suggested for a Global Red List Assessment?
A large bolete species associated with tea-tree under threat from land-use change and invasive species.
Population and Trends
Known with certainty only from 3 records all from the same general area. All known locations are in areas of bush directly adjacent to pasture farmland.
We infer the presence 3 genotypes, x 10 to account for undetected colonies, x 5 to convert to an estimate of 150 mature individuals. Area of Occupancy 4 km2
Habitat and Ecology
Xerocomellus griseoolivaceus is ectomycorrhizal with tea-tree (myrtaceae). It appears to be restricted to areas with mature stands of tea-tree, and has a northern distribution.
The known area for this species is subject to increasing tourism from the nearby Auckland city with consequent increase in disturbance in the immediate areas. The populations are also likely to decrease over the next 20 years as the impact of Kauri die-back on Kauri forest alters the surrounding forest structure. Areas are also likely to be disturbed because of future disease management actions. The impact of changing farming practices in adjacent areas may have some impact on the quality of mycorrhizae.
A number of ectomycorrhizal species associated with tea-tree (myrtaceae) in New Zealand are potentially impacted by changing agricultural practices, in particular the clearing of remnants bush fragments to accommodate large-scale irrigation machinery, and the direct impact of fertilizers and irrigation on soil chemistry and mycorrhizae extent and function.
The ectomycorrhizal fungi associated with tea-tree in northern parts of New Zealand require greater survey and characterisation.