Cantharellus rubescens is known only from its type locality within the Caatinga, where was collected in 2011 and never found again.  It was found growing gregariously to scattered under unidentified Fabaceae living trees in the Araripe-Apodi National Forest, a currently undersampled area. Despite the lack of data to infer its potential occurrence range, it is plausible to suspect that the species occurs along in the Caatinga where its specific (and up to now unclear) biotic and abiotic requirements are met. The species produces large and conspicuous basidiomes with orange pileus and pale stipe, contrasting with soil and litter where it is found growing. It is plausible to state that the species forms symbiotic relationships with an unknown plant host, as species within Cantharellus are often ectomycorrhizal. The species’ rarity, despite its conspicuous basidiomes, and lack of distribution data hinders minimal understanding of its potential distribution, ecology, and niche requirements. More efforts are required to understand C. rubescens needs, past and current trends, and if it is facing threats. Therefore, C. rubescens is assessed as Data Deficient.

Cantharellus rubescens C.C. Nascim., F.G.B. Pinheiro, Wartchow & M.H. Alves, Cryptogamie Mycologie 35 (4): 370 (2014) [MB#810094]

Chanterelle project

The species is known only from its type locality, a Caatinga area within the Araripe-Apodi National Forest in Ceará State, Brazil. The region is extremely undersampled, representing a large knowledge gap for the Brazilian Funga knowledge. Despite this, other Caatinga areas have been well sampled, and despite the species basidiomes being conspicuous, it was never collected again since 2011. Therefore, the species is considered rare, and due to a lack of minimal data regarding its distribution and requirements, it is currently impossible to infer its potential distribution. Despite this, it is reasonable to assume that C. rubescens is distributed throughout the Caatinga in areas with similar conditions as its type locality.

After fourteen years of C. rubescens holotype collection, it was never registered again. Its first and only collection was made in Araripe-Apodi National Forest, a conservation unit that allows sustainable use of its area and resources, and therefore it is not strictly preserved without human disturbances. The species produces fleshy basidiomata with a deep and bright orange color, easily contrasting with its substrate, soil under unidentified Fabaceae trees, its expected host. The sampling gap that encompasses the species type locality contributes to its decade-long lack of recollection, but other Caatinga areas are comparatively well sampled and the species was never found in these areas, allowing the species to be considered rare. Considering the current lack of knowledge regarding the species, it is impossible to viably infer its population size, potential distribution, and trends, as well as minimally understand its niche requirements and ecology. Nonetheless, it is reasonable to assume that the species has a higher probability of occurrence in adjacent areas surrounding its type locality and other Caatinga regions that hold the same biotic and abiotic conditions and its known occurrence site. Despite this, the unknown species population can potentially be under threat and instability, as habitat quality is directly linked to species occupation (Berglund & Jonnson 2003, Haddad et al. 2015), and the Caatinga is expected to suffer important pressures that will translate into high loss of area (Câmara et al., 2015).

Cantharellus rubescens grow gregariously to scattered among living unidentified Fabaceae trees in a Caatinga area within Araripe-Apodi National Forest. Despite the lack of data to infer its potential occurrence range, it is plausible to suspect that the species occurs along the Caatinga where its specific biotic and abiotic requirements are met. The species produces large and conspicuous basidiomes with deep and bright orange pileus that fades in a vanished orange in the stipe, clearly contrasting with its substrate. It is plausible to state that the species forms symbiotic relationships with an unknown plant host, possibly the unidentified Fabaceae species that grows underneath, as species within Cantharellus are often ectomycorrhizal.

As Cantharellus rubescens lacks data that enables a minimal understanding of its population parameters and requirements, it is impossible to fully understand and identify the threats to its unknown population. Despite this, the species is currently considered endemic to the Caatinga, a Brazilian ecoregion that is projected to face an increase in current anthropogenic pressures associated with land use, which will translate into a high loss of area (Câmara et al., 2015), potentially threatening the species unknown population, as habitat quality is linked to species occupation (Berglund & Jonnson 2003, Haddad et al. 2015).

Direct and precise conservation actions aiming to preserve C. rubescens population are currently hindered by knowledge lack regarding the species distribution, population size and trends, and potential niche. However, a cautionary solution would include its type locality and adjacent areas strict protection, where there is a bigger probability of C. rubescens occurrence, as the Araripe-Apodi National Forest is a conservation unit that allows sustainable use of its area and resources, and current legislation lacks reinforcement.

Further research and sampling efforts are needed in order to better understand the species distribution and potential niche, which would in turn enable total population inferences and threats mapping. Additionally, Cantharellus species are generally symbionts, thus ecological research regarding the species potential hosts would increase its ecological and niche understanding.

None known.

Berglund, H., & Jonsson, B. G. (2003). Nested plant and fungal communities; the importance of area and habitat quality in maximizing species capture in boreal old-growth forests. Biological conservation, 112(3), 319-328.

Câmara, G., Soterroni, A., Ramos, F., Carvalho, A., Andrade, P., Cartaxo Souza, R., ... & Bocqueho, G. (2015). Modelling land use change in Brazil: 2000-2050.

Haddad, N. M., Brudvig, L. A., Clobert, J., Davies, K. F., Gonzalez, A., Holt, R. D., ... & Townshend, J. R. (2015). Habitat fragmentation and its lasting impact on Earth’s ecosystems. Science advances, 1(2), e1500052.