Russula alnijorullensis is an ectomycorrhizal species associated with aliso del cerro forests (Alnus acuminata), being considered up to now an endemic species of the cloud forests of NW Argentina and Bolivia (Morrone 2002). Despite its conspicuity and sampling efforts, only eleven collections (1949-2011) from five localities are known for this species, being 2 in Tucuman, 2 in Catamarca provinces in Argentina and 1 photographic record from Bolivia in iNaturalist. Therefore, the species is likely present in approx. 60 sites in Argentina and Bolivia, based on occurrences of Alnus acuminata within Southern Yungas (Wicaksono et al. 2017). This host species is distributed in the cloud forests that are located on the border between the montane forest and the grassland, often in ravines, which generate a prosperous microclimate for the species.
One of the main threats to this ecosystem is global warming, which is expected to propitiate the conditions for the invasion of species from the Montane Forest, a vegetation floor that is at a lower altitude, displacing the cloud forests at higher altitude. It is inferred that currently there are no more than 10,000 mature individuals of R. alnijorllensis and is predicted that, mainly due to climate change, the area suitable for the specific forest will decrease by 25-50% in the next 30 years (year 2050) (Wicaksono et al 2017), causing a suspected population size reduction of at least the same magnitude, along with reduction of the habitat quality. It is assessed as Vulnerable - VU A3c; C2a(ii).

Russula alnijorullensis (Singer) Singer, Agaric. mod. Tax., Edn 4 (Koenigstein): 824 (1986)
Basionym: Russula emetica var. alnijorullensis Singer

Russula alnijorullensis is an endemic species of the Montane Forests of the southern Yungas. It is an ectomycorrhizal species associated with Alnus acuminata (Aliso del Cerro) within cloud forests in Argentina and Bolivia. It is estimated that currently there are no more than 10,000 mature individuals of R. alnijorllensis and is predicted that, mainly due to climate change, the area suitable for the specific forest will decrease by 25-50% in the next 30 years (year 2050).

Eleven collections (1949-2011) from five localities are known for this species, being 2 in Tucuman, 2 in Catamarca provinces in Argentina and 1 photographic record from Bolivia in iNaturalist. Russula alnijorullensis is an endemic species of the Montane Forests of the Southern Yungas. Since this species has an ectomycorrhizal habit, its distribution pattern is likely related to the distribution of its host, Alnus acuminata, which is distributed throughout the Andean countries and Central America, up to Mexico (according to GBIF there are 525 observations from NW Argentina to Mexico). Nevertheless, considering R. alnijorullensis records, its distribution might be restricted to the Southern Yungas, which encompasses the cloud forests of NW Argentina and Bolivia (Morrone 2002). Therefore, the species is likely present in approx. 60 sites in Argentina and Bolivia, based on occurrences of Alnus acuminata within Southern Yungas (Wicaksono et al. 2017).

Russula alnijorullensis is considered a rare species. Although it has medium-sized basidiomes and striking colors, no abundant records of this species have been found. In addition, soil and root metagenomic analysis of A. acuminata forests carried out in NW Argentina (Becerra et al. 2005, Geml et al. 2014, Wicaksono et al. 2016) did not find OTUs associated with Russula species, which could indicate that it is not a common species.
An average of 2 specimens were observed per site, but it is considered that it could appear 5 to 25 times more at each site with a greater sampling effort (20-50 specimens/site). Due to its solitary habit, it is inferred that currently there are between 2,400 and no more than 10,000 mature individuals in one subpopulation. The generation time of this species is 50 years, and it is predicted that due to climate change, the area suitable for the specific forest which harbors this species will decrease by 25-50% in the next 30 years (year 2050) (Wicaksono et al 2017), causing a suspected population size reduction of at least the same magnitude, along with reduction of the habitat quality.

Russula alnijorullensis is an ectomycorrhizal species associated with aliso del cerro forests (Alnus acuminata) in the Montane Cloud Forests of Southern Yungas.

Russula alnijorullensis is related to Alnus acuminata as an ectomycorrhizal species. This host species is distributed in the cloud forests that are located on the border between the montane forest and the grassland, often in ravines, which generate a prosperous microclimate for the species.
One of the main threats to this ecosystem is global warming, which is estimated to propitiate the conditions for the invasion of species from the Montane Forest, a vegetation floor that is at a lower altitude, displacing the cloud forests at higher altitudes. Current and future (year 2050) habitat models developed for A. acuminata predict a 25–50% decrease in suitable area (Wicaksono et al 2017).
The species is also threatened by its proximity to anthropic influence caused by cattle grazing, deforestation, and prescribed fires.

Most known collections of R. alnijorullensis were found in protected areas, therefore, the main action to prevent a possible decline of the species is the preservation of quality of habitat. In addition, cloud forest is located on boundaries of protected areas where anthropogenic influence exists. Considering this,  it is suggested to reinforce controls in these areas so the protection of the species is effective. Furthermore, it is essential to strengthen policies that stimulate citizen science, making the community know, value, and collaborate in the conservation of species.

To achieve the conservation of the species, it is essential to confirm if its distribution extends to the cloud forests of other regions of the Yungas.

No use/trade is known

Becerra A, Beenken L, Pritsch K, Daniele G, Schloter M, Agerer R. (2005) Anatomical and molecular characterization of Lactarius aff. omphaliformis, Russula alnijorullensis and Cortinarius tucumanensis ectomycorrhizae on Alnus acuminata. Mycologia 97(5):1047-57.  doi: 10.3852/mycologia.97.5.1047. PMID: 16596956.
Geml J, Pastor N, Fernandez L, Pacheco S, Semenova T, Becerra A, Wicaksono C, Nouhra E (2014) Largescale fungal diversity assessment in the Andean Yungas forests reveals strong community turnover among forest types along an altitudinal gradient. Mol Ecol 23:2452–2472. https ://doi.org/10.1111/mec.12765
Morrone JJ. (2002) Presentación sintética de un nuevo esquema biogeográfico de América Latina y el Caribe. Red Iberoamericana de Biogeografía y Entomología Sistemática
Wicaksono CY, Aguirre Guiterrez J, Nouhra E, Pastor N, Raes N, Pacheco S, Geml J (2017) Contracting montane cloud forests: a case study of the Andean alder (Alnus acuminata) and associated fungi in the Yungas. Biotropica 49:141–152. https ://doi.org/10.1111/btp.12394