Pleurotus rickii was originally regarded by Rick (1907) as a new record of Armillaria procera for Rio Grande do Sul state, Southern Brazil. Latter, Bresadola (1920) revised the specimen and described it as P. rickii in honor to the mycologist.
Pleurotus rickii is an edible species of mushroom with a greyish pileus. Although conspicuous, it has only been recorded 10 times since its description 100 years ago, from Argentina and Brazil. Most of the records are from the Atlantic Forest, which is under an array of deforestation, among other threats. Other vegetation where it occurs, the Yungas in Argentina, is also threatened, and its population is expected to be rather small. More research on neotropical macrofungi are needed to better understand its distribution, biology and population trends.
Pleurotus rickii is assessed as Vulnerable [(VU) C1], having an inferred population of between 4000 to 8000 mature individuals.
The species is known from the southern brazilian Atlantic Forest and the Yungas in Argentina, and is expected to be widespread in the regions where it occurs. It may also occur in the Humid Chaco in Argentina and Paraguay.
In Argentina it was recorded in Tucumán (Singer & Digilio 1952, Lechner et al. 2004); in Brazil it is known from Rio Grande do Sul (Rick 1907, Bresadola 1920), Santa Catarina and São Paulo (Menolli et al. 2014) states, in the Southern and Southeastern regions of Brazil.
The species is currently known from 10 sites, 8 of them in the Atlantic Forest of Brazil and 2 of them in Argentina. In Brazil, it is expected to be widespread throughout the southern and southeastern Atlantic Forest. In Argentina, it is estimated to occur throughout the Yungas and in the Atlantic Forest in Misiones, and may also be found in the Humid Chaco in Argentina and Paraguay.
The species is conspicuous, and occurs in areas that have been intensively sampled where it has only been collected few times (1 to 2 mature individuals) at each site. Thus, we assume that P. rickii is a rare species. There are at least eight known sites where this species occurs. Even though the area of potential suitable habitat is large, the total population size is estimated between 4000 and 8000, calculated from an estimated 1000 potential sites, each with 4-8 mature individuals.
The forests where the species is found are declining in area and quality due to continuing deforestation, increase in fire frequency and intensity, and impacts of climate change. The number of individuals are estimated to be smaller now than they were in the past, and the decline is predicted to continue into the future, with a projected decline in population size of at least 10% over the next 30 years.
Population Trend: Decreasing
Saprotrophic on dead trunks of angiosperms in Neotropical forests, including the Yungas, humid Chaco and Atlantic Forest (Bresadola 1920, Lechner 2004, Menolli et al. 2014).
The Atlantic Forest is regarded as one of the global biodiversity hotspots for conservation priorities due to their high diversity, endemism rates and habitat loss (Myers et al. 2000). The Yungas, although covering less than 2% of Argentina, still plays a major role in the biodiversity of the country, where about 50% of its species can be found (Brown et al. 1993, Vides-Almonacid et al. 1998). About 300 km² of the Yungas are currently protected, but human occupation and land use and transformation to soybean fields continues to cause loss habitat and facilitate fire (Brown et al. 2002). In some areas the loss reaches the rate of 100 km² per year (Brown et al. 2002). Both areas continue to be threatened with further decline due to land use changes, deforestation, and ‘savannization’ of tropical forests of South America due to climate change in the next decades (Salazar et al. 2007). The Chaco domain, where the species probably also occur, also suffers from deforestation for agricultural land implementation (Boletta et al. 2006), with soybean cultivation being the greatest cause of cleaning in Argentina, Brazil, and Paraguay (Grau et al. 2005, Fearnside 2001, Kaimowitz & Smith 2001).
There is a need for habitat conservation and better management, including enhanced public policies, based on conservation plans.
Additional mycological surveys in other sites of Atlantic Forest, humid Chaco and the Yungas is needed to confirm its potential distribution and better understand its distribution. Revision of herbarium specimens may reveal additional records of this species and help clarify its distribution. As P. rickii is an edible species, studies about its life cycle, phenology and commercial cultivation should be carried, as this could help preserve the species ex-situ.
Edible according to Singer & Digilio (1952), trade unknown.
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