Phlebopus bruchii is currently known only from
subxerophytic Montane Chaco Forests (“Bosque Serrano”) of central Argentina, in an altitudinal range from 600 to 1400 m a.s.l, in the Sierras Chicas and Sierras Grandes of Córdoba and San Luis provinces. The species has a potential distribution throughout the extension of the Montane Chaco Forests from Central Argentina, along northern-central mountains reaching southern Bolivia, restricted to an altitudinal range between 600-1400m, associated with mature forests patches where Fagara coco (Rutaceae) and Lithraea molleoides (Anacardiaceae) are present. However, there are no records of the species outside Córdoba and San Luis provinces (Central Argentina), hence so far being endemic of this area even though it has been searched for in other suitable habitat. The species is likely undergoing severe population decline due to habitat loss. The forest fragments where it grows are extremely endangered and more than 90% have been lost between 1969 and 1999 (Zack et al 2004, Atala et al 2009). This decline is still ongoing, mainly due to logging and fire. As the species is restricted to these closed canopy forests, Phlebopus bruchii is estimated to have had a population decline of 80-90% in the last 50 years, a decline that is still ongoing.
Phlebopus bruchii is the only native wild edible species from Cordoba forests sought and collected by local people. It is considered of better quality than other exotic species (such as Suillus spp.) that grow in exotic pine forests established in the region and is under threat from uncontrolled harvesting. The development of a sustainable use management plan of the species and a legal frame for its commercialization is needed. Because of the decline in suitable habitat and intense pressure from harvesting the species is assessed as Critically Endangered.
Phlebopus bruchii (≡ Boletus bruchii Speg.) was described by Spegazzini (1926). The species was synonymized with Phlebopus tropicus (Rick) Heinem. & Rammeloo (under Phaeogyroporus tropicus (Rick) Singer) (Singer 1949), however the morphological characters support its current placement as an independent species in Phlebopus (Heinemann & Rammeloo, 1982).
Phlebopus bruchii (Speg.) Heinem. & Rammeloo is the only native edible bolete species presents in the subxerophytic montane chaco forests “Bosque Serrano” of central Argentina. Phlebopus brouchi is associated to mature forests patches dominated by Fagara coco (Gill.) Engl (Rutaceae) and Lithraea molleoides (Vell.) Engl. (Anacardiaceae) in a range from 600 to 1400 m a.s.l. These forests are extremely endangered, more than 90% have been lost between 1969 and 1999 (Zack et al 2004, Atala et al 2009). In addition, Phlebopus bruchii is heavily harvested by local people and there is no management plan, and year by year its occurrence has been declining.
Phlebopus bruchii is currently known only from the subxerophytic Montane Chaco Forests (“Bosque Serrano”) of central Argentina in the Sierras Chicas and Sierras Grandes of Córdoba and San Luis provinces at an altitudinal range of 600 to 1400 m a.s.l. The species has a potential distribution throughout the Montane Chaco Forests from central Argentina along the north-central mountains reaching southern Bolivia, associated with mature forests patches where Fagara coco (Rutaceae) and Lithraea molleoides (Anacardiaceae) are present. However, there are no records of the species outside Córdoba and San Luis provinces (Central Argentina) even though it has been searched for in other suitable habitat.
To date the species is known only from the Cordoba region of central Argentina, found in the Bosque Serrano in the “Sierras Chicas” and “Sierra Grande” mountains, in an altitudinal range between 600-1400m associated with mature forests patches dominated by Fagara coco (Rutaceae) and Lithraea molleoides (Anacardiaceae). This forest type extends from central Argentina to the north, in a thin strip of intermittent patches reaching southern Bolivia. The species is expected to be found throughout this habitat, although it has not been reported outside of Cordoba and San Luis provinces.
There are an estimated 100 sites where the species is known to be harvested for food (with different extraction pressures). There are an estimated 30-50 mature individuals at each site in Cordoba where the species is expected to be most abundant. It is conservatively estimated that throughout its potential distribution there are approximately 300 sites, each with an average 20-40 mature individuals. Based on this estimation, the total number of mature individuals are calculated at 8,000-12,000. However, based on satellite data, there is approximately 160,000 ha of closed canopy, highly fragmented forest remaining in the Montane Chaco Forests in Cordoba province, where 90% of Phlebopus bruchii known occurences are. Mature individuals are usually found forming small individual clusters of basidiomata, with only one cluster on average per hectare. Extrapolating from 1 -2 mature individuals per ha, there is a possibility of 160,000 - 300,000 mature individuals in Cordoba Province. Although these two methods of estimating the number of mature individuals give very different results, the species is likely undergoing severe population decline due to habitat loss. The forests fragments where it grows are extremely endangered and more than 90% of its area was lost between 1969 and 1999 (Zack et al 2004, Atala et al 2009). This decline is still ongoing, mainly due to logging and fire. As the species is restricted to these closed canopy forests, Phlebopus bruchii is estimated to have had a population decline of 80-90% in the last 50 years due to habitat loss that is continuing.
Population Trend: Decreasing
Phlebopus bruchii is distributed in the subxerophitic Montane Chaco forests of Cordoba mountains, growing on the ground associated with Fagara coco trees and Lithraea molleoides (in an elevation range of 600 to 1400 m a.s.l.). The species is expected to occur throughout the distribution of the “Chaco Serrano forests” from Argentina to Bolivia. However, its presence outside the Córdoba mountains is not confirmed. As with most boletes, this species was assumed to form an ectomycorrhizal (ECM) association with trees, but it has been shown that a mycorrhizal relationship is not established (greenhouse and field observations), and the species is considered a saprotroph (Nouhra et al 2008).
The species is strongly threatened by deforestation of the Mountain chaco forests in addition to uncontrolled harvesting. The Montane Chaco Forests in Córdoba province covered 2,334,712 ha in 2009, of which only 8.25% (193,689 ha) correspond to dense or mature forest, as the rest has been degraded to open forests, shrublands and grasslands (Atala et al 2009). During the last 10 years, intentional fires, as well as the advance of the agricultural frontier and urbanization have continued at an increasing scale, causing an additional decline in the Montane Chaco Forests area, and there is only an estimated 160,.000 ha of high quality forest remaining. Forest fire is the most important threat, e.g., 22,000 ha were burned in La Paz locality in December 2019. La Paz is home to some of the most important sites, and P. bruchii has been shown to be an ethnomycological important species in the region (Flamini et al 2018).
Phlebopus bruchii is the only native wild edible species from Cordoba forests sought and collected by local people. It is considered of better quality than other exotic species (such as Suillus spp.) that grow in exotic pine forests established in the region. This has resulted in it having a higher price resulting in a greater extraction pressure (Flamini et al 2018). In Córdoba Mountains a single farmer can collect approximately 25-30 kg (3 kg dehydrated) during the season (Flamini et al 2018), even in Conservation Areas. The exploitation of this resource is carried out without any legal framework controlling it, nor is there any sustainable management plan that guarantees the conservation of the species.
The main action to prevent the decline of the species is the protection of its habitat. A survey to verify the presence and abundance of the species in the current Protected Areas that includes “Bosque Serrano” is needed, as well as enforcement of public policies aimed at recovering secondary forests and supporting existing “forests restoration programs” organized by local NGOs. Surveys are needed to facilitate decisions t about the creation of new conservation areas, as well as the reintroduction of the species in protected areas where it is not present or occurs in low abundance. The development of a sustainable use management plan of the species and a legal frame for its commercialization is also urgent to guarantee sustainable harvest (number and stage of individuals).
More surveys are needed to confirm the potential distribution of the species. The relationship of this fungi with its host tree species has been partially addressed, confirming the absence of an ectomycorrhizal relationship with the supposed host tree (Nouhra et al 2008). However, it is not clear why the species seems to prefer particular sites associated with these trees. Further studies are needed in order to understand the requirements (relationships/adaptations) of the species.
As the the species has not been sequenced and not included in any phylogenetic analysis, including the species in such studies could help understand its ecology, as different clades in Boletales present different ecological roles.
Although the species is able to be grown in culture (petri dishes) (Descamps 2002), the production of basidiomata ex-situ has not been investigated. Development of cultivation protocols are needed to decrease its extraction pressure. The chemical and nutritional composition of basidiomata need to be characterized to assess its quality compared to other edible species (Suillus spp.).
The first published record of the edibility of this species was reported by Spegazzini (1926b). However, until relatively recently the species was largely collected, appreciated and consumed by indigenous people. Nowadays it is sold sliced and dried by locals in villages and at city markets (Nouhra et al. 2008, Flamini et al 2018). In 2012 the species was included in the National Alimentary Code, as a wild edible species. However its nutritional data have never been described. Currently, it is being harvested and commercialized as part of the economy of many local people in the touristic corridor of Sierras de Córdoba, but its extraction and commercialization has been developed without any sustainable use program or legal framework.
Atala, D., Baudo, F., Álvarez Igarzabal, M.A., Fernández, F., Medina, A. M., Miatello, R.A. and Sonzini, B. 2009. Proceso y Programa de Ordenamiento Territorial de los Bosques Nativos de la Provincia de Córdoba. Módulo de Gestión Ambiental Sierras y Pampas de Altura. Secretaria de Ambiente de la Provincia de Córdoba. Córdoba, Argentina. p. 202.
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