Assessment Notes

Justification

This species has an estimated population size of 1,600-16,000 mature individuals, with very small subpopulations of around 40 mature individuals, and a projected continuing decline due to ongoing threats of habitat fragmentation and degradation including invasive species and fire. It is, therefore, precautionarily assessed as Endangered C2a(i).

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Taxonomic notes

The basionym for this species is Octaviania chilensis E. Horak, (Sydowia 17(1-6): 311 (1964) [1963]). However, this species was transferred to the genus Stephanospora by Vidal as Stephanospora chilensis (E. Horak) J.M. Vidal (Revta Catal. Micol. 26: 102 (2005) [2004]).

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Geographic range

This species is rare, but has been found at several sites in southern Chile, including both in the coastal range and wet sites in the Andes mountains.

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Population and Trends

This species is known from eight collections from four sites. Around 4 genets are expected per site, with each genet representing 10 ramets, i.e. 40 mature individuals per site. It is likely to occur in additional sites, however much of the habitat is fragmented and although truffles generally have low detectability, the region has been relatively well surveyed and the species has been found both in spring and autumn. We therefore take a precautionary approach and apply a multiplier of 10-100 to account for the unknown sites, resulting in a total population size estimated as 1,600-16,000 mature individuals, with very small subpopulations of approximately 40 mature individuals. 

This species occurs in some of Chile's protected areas (including Parque Nacional Perez Rosales, Reserva Nacional Los Ruiles, and Reserva Nacional Nonguén) but in the northern part of its range these sites are potentially endangered by fire and invasive plants, and this part of the range has undergone significant degradation and fragmentation in the last 50 years. A continuing decline in the number of mature individuals is inferred based on these ongoing threats.

Population Trend: decreasing

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Habitat and Ecology

Stephanospora chilensis is found in leaf litter of Nothofagaceae forests or mixed Nothofagaceae forests. Although this species can be found in small forest patches, relatively high quality forest seems to be required by this species. Evidence suggests that species in this group of fungi are saprotrophs or root biotrophs but the exact ecology is unknown.

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Threats

This species is threatened across its range due to grazing, timber harvesting, road-building, fire and potentially by drought due to climate change. In the northern part of the range, Nothofagaceae forests are seriously fragmented and disturbed. Invasive plants (especially Broom, Cytisus scoparius) and pine plantations also threaten the habitat.

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Conservation Actions

Preservation of high quality forest, particularly in the northern range of this species, will be critical to the long-term survival of this fungus. Mitigation of invasive plants and reduction of ongoing grazing in conservation areas will be important in some of the reserves in the northern range of this species. This species occurs in some of Chile's protected areas (including Parque Nacional Perez Rosales, Reserva Nacional Los Ruiles, and Reserva Nacional Nonguén) but in the northern part of its range these sites are unable to protect the species from some serious threats such as fire and invasive plants. This taxon may represent a species complex and more work is needed to determine whether multiple species are present within this one morphological species. Also, the distribution of this species requires further research.

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Use and Trade

This species has no known human uses.

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Source and Citation

Furci, G. & Smith, M. 2021. Stephanospora chilensis. The IUCN Red List of Threatened Species 2021: e.T172833039A195455314. https://dx.doi.org/10.2305/IUCN.UK.2021-1.RLTS.T172833039A195455314.en .Accessed on 9 April 2024

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• Country occurrence