Cantharellus attenuatus is known from South Australia. While there are some potential records from New Zealand these have been excluded from this assessment due to uncertainty. potentially restricted to an extent of occurrence of <40,000 km2, there have been high levels of forest cover loss over recent decades, assumed to be associated with agriculture and fire events. It may not be completely restricted to forest habitats, and rates of forest cover loss may not accurately correspond to population trends in C. attenuatus. However, an ongoing three generation decline of 30-49% is precautionarily suspected and so C. attenuatus is assessed as Vulnerable under criterion A4c.
It is probably not a Cantharellus, or at least the spore-shape does not appear typical for a Cantharellus (I. Olariaga Ibarguren in litt. 2022).
The species was first described from Mt. Lofty (now within Cleland National Park) in Southern Australia (Cleland 1934). Records also appear to come from Belair National Park (Grgurinovic and Simpson 2001), although such description appears to suggest the species only occurs there and so it is questionable whether this reference actually refers just to the Mt. Lofty description given how close the sites are. GBIF (2023) also includes records from the Mary Seymour Conservation Park. Therefore, it may persist at additional localities in this southern part of South Australia, and potentially into Victoria. Within the potential wider distribution in South Australia, it could have a maximum extent of occurrence of 32,938 km2.
Furthermore, there are four specimens in GBIF assigned to this species (GBIF 2023). However, two of these at least were collected as Cantharellus c.f. attenuatus, so do no necessarily refer to this species. Given the uncertainty, the species’ occurrence in New Zealand is considered to be unconfirmed.
Within the potential range of this species in South Australia there has been a significant reduction in forest cover at >30% canopy cover over recent years. Between 2001 and 2022, 24% of forest cover was lost (see World Resources Institute 2023), and there appears to be a degree of connection to the impacts of fire events, as peaks in forest cover loss seem to correlate with years of peak fire activity. Directly using this measure as a proxy for population change, though, is risky as the species may not be completely dependent on forest, and it is plausible that areas could be denuded of their above-ground vegetation by fire, yet the species may potentially persist in the soil. Such losses to fire have become more regular and will likely continue into the future (Jones et al. 2022), so if there were a 1:1 relationship this would extrapolate to a 57.1% reduction over three generations (50 years; Dahlberg and Mueller 2011). However, this is likely to be an overestimate based on the above considerations, but precautionary an ongoing decline of 30-49% over three generations could be suspected.
This species grows in clusters (Cleland 1931), and it could be estimated that there are a potential 5-10 genets per site, which would undergo a scaling factor of 10 to convert to mature individuals per Dahlberg and Mueller (2011); thus 50-100 mature individuals per site. While there is some uncertainty there are at least two sites known in South Australia (potentially three) and given the availability of suitable habitat the number of sites could be 100 times greater. Therefore the overall population size could fall in the range 10,000-30,000 mature individuals.
Population Trend: Decreasing
This species, described as possessing pear-shaped spores and a thin outer white flesh, tends to grow in clusters on the ground (Cleland 1934). Published data on habitat preference appears to be lacking, however based on this record by Cleland, this ectomycorrhizal species (Grgurinovic and Simpson 2001) likely occurs within temperate forest; and it has been noted on sandy soils under shrubs (Department of Environment and Natural Resources 2023 in GBIF 2023).
This species’ area is known to be degraded as a result of livestock farming and agriculture. Annual forest cover loss figures from World Resources Institute (2023) also suggest that fire may have a significant impact on forest cover within its range, as years of greater incidence of fire appear to have higher rates of forest cover loss.
This species occurs within protected areas.
Further research into the distribution and habitat preference of this species is needed in order to more accurately deduce this species’ geographic range and population trends.