Assessment Notes

Justification

Descolea archeureta is an endemic species of southern Chilean Nothofagaceae-dominated forest ecosystems. The species is known from 9 records from the regions of Biobio, Araucanía and Magallanes (Halling 1981, Kuhar et al. 2017). The species is an obligate ectomycorrhizal fungus with Nothofagaceae and the loss of its mycorrhizal hosts directly impacts its population. Although this species has a wide distribution in Chile it appears to be a rare species that is restricted to undisturbed, mature forest. The main known threat is habitat loss and degradation. It is assumed that Nothofagaceae forest have reduced in coverage by 45% between 1973 to 2010 (Miranda et al. 2017) and this decline continuing. Anthropogenic pressure on Nothofagaceae forests and habitat degradation is mainly due to deforestation, due to land use changes for exotic tree plantations. Forest fires in Chile have also increased in intensity and frequency in recent years with forest loss reported by global forest watch of 1.95Mha between 2001 and 2022 (World Resources Institute 2023). This includes many natural Nothofagaceae forest area, especially from Biobio and Araucania. Based on this trend we suspect that D. archeureta has undergone at least a similar rapid population decline in the past resulting in a population reduction higher than 50% in the last 50 years (three generation time period). Therefore, D. archeureta is assessed as Endangered under criterion A2c.

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Geographic range

Descolea archeureta is an ectomycorrhizal fungus associated with Nothofagaceae species in southern Chile. The species is known from nine records from the regions of Biobio, Araucanía and Magallanes (Halling 1981, Kuhar et al. 2017).

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Population and Trends

Descolea archeureta is an endemic species restricted to southern Chile Nothofagaceae-dominated forest ecosystems. The species is an obligate ectomycorrhizal fungus with Nothofagaceae and a loss of its mycorrhizal hosts directly impacts D. archeureta. Although this species has a wide distribution in Chile, reported in the regions of Biobio, Araucanía and Magallanes (Halling 1981, Kuhar et al. 2017), it appears to be rare, being restricted to undisturbed, mature forest. Only nine collections of this species have been made even after long term collection efforts since 2008. The holotype was collected in 1906 (kept at Farlow Herbarium) and since then there have been only eight others from 2016, kept at University of Florida Herbarium (FLAS). No additional collections were found at other herbaria (FH, LPS, BAFC, CORD and NY). A considerable decline of size population of this fungal species is suspected due to extensive past habitat loss and deterioration, which resulted in significant declines in its mycorrhizal hosts in Chile. Further pressure and population reductions are expected to continue. It is assumed that Nothofagaceae forests have reduced their extent by 45% between 1973 to 2010 (Miranda et al. 2017) and since this trend hasn't changed it is considered that a reduction of more than 50% has taken place up to the 2020's. Based on this trend we suspect that D. archeureta has undergone at least a similar rapid population decline in the past resulting in a population reduction higher than 50% in the last 50 years (three generation time period).

Population Trend: decreasing

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Habitat and Ecology

Descolea archeureta is a hypogeous species restricted to southern Chile Nothofagaceae dominated forest ecosystems (Halling 1981, Kuhar et al. 2017). The species is obligatorily ectomycorrhizal with Nothofagaceae, found in organic soils in mature and undisturbed forests. It is gregarious and considered a rare species at the sites where it has been reported.

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Threats

The main known stress to Descolea archeureta is habitat loss and fragmentation due to deforestation resulting in population declines of Nothofagaceae. It is assumed that Nothofagaceae forest has reduced in its coverage by 45% between 1973 to 2010 (Miranda et al. 2017) and this decline is continuing. Anthropogenic pressure on Nothofagaceae forests and habitat degradation are mainly due to deforestation due to land use change to replace them with exotic tree plantations (Pinus spp. and Eucalyptus spp.). Forest fires in Chile have also increased in intensity and frequency in recent years with forest loss reported by global forest watch of 1.95Mha between 2001 and 2022 (World Resources Institute 2023). This area includes many natural Nothofagaceae forests, especially from Biobio and Araucania.

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Conservation Actions

Habitat protection and enhanced forest management are needed in Chile. Nothofagaceae populations in Chile are largely unprotected and susceptible to deforestation or degradation for plantations of exotic species and fire. Due to its potential association with mature forest, all conservation actions should be focused on conservation of intact habitats. Due to a higher number of natural reserves conserving remaining of natural areas, there is a lower threat level for the species in Magallanes compared with Araucania and Biobio. Research is needed to evaluate population trends and further document distribution. Molecular analyses are needed for phylogenetic inference and to provide identified sequences to enable identification of environmental samples required for molecular-based ecological studies.

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Source and Citation

Torres, D., Smith, M., Corrales, A., Trierveiler-Pereira, L., Orellana Mondol, A. & Bustamante, C. 2023. Descolea archeureta. The IUCN Red List of Threatened Species 2023: e.T245800702A245801454. https://dx.doi.org/10.2305/IUCN.UK.2023-1.RLTS.T245800702A245801454.en .Accessed on 9 January 2025

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• Country occurrence