Assessment Notes

Justification

Acanthocorticium brueggemannii appears to be restricted to the subtropical Brazilian dense ombrophilous forest (Atlantic Forest domain), which is restricted to the coastal zone, but restricted to mature forests in the south of Brazil. This distribution is expected because the adjacent areas are well studied regarding their corticioid funga, but it is only known from two collections along the same trail in the same site less than 20 km from the sea, at about 450 m asl. located in the State of Santa Catarina. The species is considered saprotrophic (but data from a related undescribed species suggest that it could be a biotroph (mycorrhizal)). Its basidiomes grow on the lower side of fallen trunks of hardwoods lying on the forest ground.

The main threatening processes for A. brueggemannii involve loss of habitat and declining habitat quality. About 60% of the Brazilian population is concentrated in the coastal zone (Rezende et al. 2018). The urbanization of the Brazilian Coastal Zone is the most important factor for loss of habitat, but there is also an expansion of silvicultural areas. Climate change is also an important threat since it can promote important changes in the environment of the species. The species is considered to be rare, and the total population is estimated at no more than 10,000 mature individuals, distributed in a single subpopulation. The current cover of Atlantic Forest is reduced to 28% of its original extension, and most of the remaining cover is drastically fragmented (Rezende et al. 2018). The population decline is suspected at 15% in the last 30 years, and a decline of 15% is also expected for the next 30 years. This decline primarily results from habitat loss and degradation, due to land use changes and climate change impacts. Considering the population size concentrated in only one subpopulation and habitat loss and degradation, this species is assessed as Vulnerable (VU) under C2a(ii), based on a small population undergoing a continuing decline.

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Taxonomic notes

Acanthocorticium brueggemannii was described by Baltazar et al. (2015) as a new genus and species. It has no synonyms. Molecular evidence places the species among cyphelloid fungi within Agaricales, which could make this species important to understand several questions regarding the evolution of Agaricomycetes.

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Geographic range

Acanthocorticium brueggemannii is only known from two collections along the same trail in the same site, one in September 2010 and another in March 2012. This site is located in the State of Santa Catarina, southern Brazil, at the border of a large conservation area. It is expected to occur along the Brazilian subtropical dense ombrophilous forest (Atlantic Forest domain). This southern distribution is expected because it has not been recorded in the adjacent State of São Paulo to the north which is well studied regarding its corticioid funga, in addition to differences in vegetation and climatic conditions above this subtropical region.

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Population and Trends

Acanthocorticium brueggemannii is considered to have a distribution restricted to mature forests in the subtropical ombrophilous dense forest in southern Brazil. Despite its low detectability, the potential area of occurrence and other adjacent areas have been intensively sampled by experts and collaborators in the last decades, but only two specimens have been found, both at the same site. For these reasons, the species is considered to be rare. It is estimated that there are up to 500 potential sites with up to 20 mature individuals at each site. Therefore, the total population size is estimated at no more than 10,000 mature individuals, distributed in a single subpopulation.

The species' population was probably larger in the past and the number of sites have likely decreased considerably. The current cover of Atlantic Forest is reduced to 28% of its original extension, and most of the remaining cover is drastically fragmented (Rezende et al. 2018). The habitat decline in the Atlantic Forest is estimated at 7.5% over the past 30 years (da Silva et al. 2020), so considering the annual average loss within this time period it is possible to estimate habitat loss of 7.5% in the next 30 years (three generations). Considering that habitat loss is accompanied by a major loss in habitat quality (Joly et al. 2014), a population decline is suspected at 15% over the last 30 years with another 15% is expected over the next 30 years.

Population Trend: Decreasing

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Habitat and Ecology

Acanthocorticium brueggemannii appears restricted to the subtropical Brazilian dense ombrophilous forest. The species is saprotrophic, and its basidiomes grow on the lower side of fallen trunks of hardwoods lying on the forest ground. The only known site of occurrence is less than 20 km from the sea, but at approximately 450 m asl. The site is within the dense ombrophilous forest, a typical vegetation type from the coastal zone of the Brazilian Atlantic Forest biome.

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Threats

The main issue for Acanthocorticium brueggemannii is loss of habitat and decline of habitat quality, as a result of multiple threats such as urbanisation, agriculture and logging. Its occurrence is likely restricted to the coastal zone of the State of Santa Catarina. About 60% of the Brazilian population is concentrated in the coastal zone (Rezende et al. 2018). The urbanization of the Brazilian coastal zone is the most important factor for loss of habitat. There is also an expansion of silvicultural areas with exotic tree species. Pinus spp. are one of the most cultivated trees, and there is no evidence that A. brueggemannii can grow on woods other than hardwoods. Climate change is also an important threat since it can promote important changes in the environment of the species.

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Conservation Actions

The main action required is to preserve the Atlantic Forest domain, especially the dense ombrophilous forest, keeping the protection of conservation areas, creation of new ones, and promoting the restoration of habitats whenever possible. The preservation of pristine forests could be critical for the maintenance of this species, since it occurs in large fallen hardwood logs. The application of current legislation would be very important to reach these goals. Furthermore, preventing the urbanization process is also very important to mitigate the loss of habitat.

Surveys are needed to find more specimens of this species and possibly new sites of occurrence. Recent research brings to light evidence that an undescribed species of Acanthocorticium could establish ectomycorrizhal relationships (M. Contreras-Pacheco et al. unpublished data). Considering this report, it is important to establish whether A. brueggemannii is a biotrophic or necrotrophic species.

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Use and Trade

There are no reported uses and trade.

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Source and Citation

Baltazar, J.M., Calaça, F., Costa-Rezende, D.H., Alves-Silva, G., Canêz, L., Monteiro, M., Trierveiler-Pereira, L. & Gusmao, L. 2024. Acanthocorticium brueggemannii. The IUCN Red List of Threatened Species 2024: e.T265094520A265151786. Accessed on 24 November 2025.

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• Country occurrence