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Gerronema viridilucens Desjardin, Capelari & Stevani

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Scientific name
Gerronema viridilucens
Author
Desjardin, Capelari & Stevani
Common names
 
IUCN Specialist Group
Mushroom, Bracket and Puffball
Kingdom
Fungi
Phylum
Basidiomycota
Class
Agaricomycetes
Order
Agaricales
Family
Marasmiaceae
Assessment status
Published
Assessment date
2021-10-20
IUCN Red List Category
VU
IUCN Red List Criteria
C2a(ii)
Assessors
de Paula Drewinski, M., Kossmann, T., Neves, M.A., Martins da Cunha, K., Costa-Rezende, D.H., de Andrade Borges, M.E., Santos Ferreira da Cruz, R.H. & Drechsler-Santos, E.R.
Reviewers
Mueller, G.M.

Assessment Notes

The content on this page is fetched from The IUCN Red List of Threatened Species: https://www.iucnredlist.org/species/209595462/209597089

Justification

Gerronema viridilucens was described in 2005 based on material collected from the bark of living Eugenia fluminensis O.Berg. trees in the Atlantic Forest domain. The species is so far known only from the Parque Nacional Turístico do Alto Ribeira (PETAR), south of São Paulo State in Brazil. PETAR is one of the oldest conservation areas in the state of São Paulo. It consists of mature Dense Ombrophilous Forest. The species is expected to occur in another 200-500 sites with a total population between 6,400 and 16,000 (but most likely less than 10,000) mature individuals, restricted to one subpopulation. The population is expected to decline by at least 16% over the next three generations due to ongoing habit loss and degredation. G. viridilucens is a saproptrophic species and is the only known bioluminescent species in the genus. The species is assessed as Vulnerable according to criterion C2a(ii).

Geographic range

There are only 8 collections of the species, all found in the Parque Estadual Turístico do Alto Ribeira (PETAR), an Atlantic Forest remnant in the region of the Vale do Ribeira, south of São Paulo State. The species is expected to occur in other locations in the southeast and south of the Brazilian Atlantic Forest, in regions of mature and well-preserved forest.

Population and Trends

There are 8 collections of the species from 3 sites, all found within the same conservation area in the Parque Estadual Turístico do Alto Ribeira (PETAR). The five collections studied to describe the species were collected at the same locality (S24°16-38', W48°29-44') on different dates (December 11, 2002; December 13, 2002; February 27, 2003; September 2003 and April 2004). The other known specimens were found at other localities in the park on March 2005 and March 21, 2007. PETAR is one of the oldest conservation areas in the state of São Paulo and the predominant vegetation is Dense Ombrophilous Forest, a mature forest, with large emerging species. Gerronema viridilucens is a small and inconspicuous species, and the type collections (holotype and paratype) were found growing on bark of living Eugenia fluminensis, a late secondary successional species of Myrtaceae. The species is expected to occur in other sites in the southeast and south of the Brazilian Atlantic Forest, in regions of mature and well-preserved forest. Considering the history of collections and studies of macrofungi in the states of São Paulo, Paraná, Santa Catarina and Rio Grande do Sul, the species is expected to occur in up to another 200-500 sites with 32 individuals per site, with an estimated population size of 6,400–16,000 mature individuals, restricted to one subpopulation. 

The population is suspected to decline by at least 16% over the next 30 years (three generations). Since European colonization, the Brazilian Atlantic Forest has been exposed to high levels of deforestation and fragmentation (Joly et al. 2014). There is only 28% of native vegetation cover remaining, including both forest (26%) and non-forest native formations (2%). Much of the mapped vegetation consists mainly of edge-affected or secondary vegetation disconnected from large fragments (Rezende et al. 2018). According to Rezende et al. (2018) only 30% of the total vegetation cover is located inside protected areas. The remaining 70% may be protected by other conservation measures, which may allow intervention and deforestation in specific situations. A population decline was estimated in light of extension loss of suitable habitat (Joly et al. 2014, Rezende et al. 2018, da Silva et al. 2020) and the putative influence that habitat degradation has on species occupation in a given environment (Berglund and Jonsson 2005, Haddad et al. 2015).

Population Trend: decreasing


Habitat and Ecology

The species is saprotrophic, growing on wood, solitary to scattered, in bark of living Eugenia fluminensis (Myrtaceae) and possibly other trees in high quality Brazilian Atlantic Forest. According to Desjardin et al. (2005) the species is found during September to April when relative humidity is 85-90% and temperatures vary from 20-30°C. The species is bioluminescent and the lamellae emit bright yellowish-green light. This is the only known species of Gerronema reported to be bioluminescent (Desjardin et al. 2005). G. viridilucens bioluminescence is observed in both mycelium and basidioma.

Threats

Primary threats include habitat loss and fragmentation, logging, fire, and climate change. The expansion of urban areas is also an important pressure further reducing the area of the Atlantic Forest (Joly et al. 2014). Weak enforcement of conservation policies threaten some remaining high quality areas where the species occurs.

Conservation Actions

The main action to prevent the decline of the population is preservation of Atlantic Forest, the species' habitat. The occurrence of the species is only known for the Parque Estadual Turístico do Alto Ribeira (PETAR). The park is known for containing a huge amount of caves (almost 500 catalogued), which attracts many tourists; about 39,000 visitors a year. To guarantee the preservation of the species, it is necessary to maintain the conservation area, control visitation and appropriate management, based on the park's management plan. Effective enforcement of existing conservation policies and laws is also required.

There is only one DNA sequence of Gerronema viridilucens available. There are no studies on Gerronema diversity in Brazil, the phylogenetic position of the genus is still uncertain and needs to be further investigated. Despite the intense light emitted by the species and the facility of finding the mushroom at night in the forest (Desjardin et al. 2005), the species' basidiomata are small and inconspicuous by day, when most collections are made. It is necessary to expand sampling and carry out more nocturnal collections in other locations in the south and southeast of the Atlantic Forest. It is also important to carry out studies on the species occurrence substrate to better understand its possible distribution, as well as the impact of tourism as a potential threat to the species.

Use and Trade

It is unknown if this species is used.

Source and Citation

de Paula Drewinski, M., Kossmann, T., Neves, M.A., Martins da Cunha, K., Costa-Rezende, D.H., de Andrade Borges, M.E., Santos Ferreira da Cruz, R.H. & Drechsler-Santos, E.R. 2022. Gerronema viridilucens. The IUCN Red List of Threatened Species 2022: e.T209595462A209597089. https://dx.doi.org/10.2305/IUCN.UK.2022-1.RLTS.T209595462A209597089.en .Accessed on 28 July 2023

Country occurrence