Assessment Notes

Justification

Stropharia agaricoides is a mushroom forming species restricted to Araucaria moist forest, a very fragile habitat that is estimated to have decline by nearly 97% and that is projected to further decline in the future. Its total population is estimated at no more than 10,000 mature individuals in one subpopulation distributed in up to 250 sites. It is assessed as Vulnerable.

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Geographic range

The species is restricted to the Araucaria moist forests of the Atlantic Forest domain. It is currently known only from São Francisco de Paula National Forest in Rio Grande do Sul, southern Brazil but is expected to be found throughout the Araucaria moist forests in southern Brazil and a small part of northern Misiones, Argentina.

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Population and Trends

Stropharia agaricoides is currently known only from the type locality. It is likely to be a rare species as there are few records even in well surveyed areas in its potential range, and only 5 specimens have been found over the 10 years since its description. The habitat in which the species is found has declined about 97%, with the remaining areas heavily fragmented. 80% of the fragments are less than 50 ha and are surrounded by agricultural lands. These scattered fragments have been shown to hold a smaller diversity than larger forests, and show signs of disturbance (Ribeiro et al. 2009, Souza et al. 2012, Nodari 2016). The total population size is estimated at no more than 10,000 mature individuals distributed in up to 250 sites, each with up to 40 mature individuals. Between 2001 and 2018, there has been a loss in cover of approximately 3.1% (13% loss and 9.9% gain) (World Resources Institute 2020). Additionally, in chronically disturbed areas, the Araucaria moist forests are kept at early successional stages, which may not support the have conditions to support species from pristine fungal communities such as S. agaricoides. Despite this, though, it is thought that the species could be said to be in one subpopulation.

Population Trend: decreasing

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Habitat and Ecology

Stropharia agaricoides is a saprotrophic mushroom found on soil and litter in Araucaria moist forests.

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Threats

The species is threatened by habitat loss, mainly due to logging, fire and conversion of forests into agricultural lands. Araucaria moist forests have lost about 97% of their original extent, with 80% of the remaining area being composed of disturbed fragments under 50 ha inside of private farms and surrounded by crop fields and grasslands. Only 3.1% of the remaining habitat is in protected areas, which corresponds to 0,09% of the original Araucaria moist forests. Araucaria moist forests are restricted to higher altitudes with subtropical climates, high year-long precipitation, cold winters and temperate summers. Studies have shown that by 2070, Araucaria angustifolia, the dominant tree of the AMF, will likely be restricted to highland microrefugia as an impact of climate change. This means that the structure of the AMF will likely be drastically different, or that the AMF itself will also be restricted to these areas.

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Conservation Actions

The main actions required to preserve the species are the protection of its habitat, restoration of Araucaria moist forests, and creation of new conservation areas to harbour the probable microhabitats to which the AMF may be restricted in the future. Also, measures must be taken to assure that the protected AMF state. More surveys are needed in other areas to confirm the species range, including its association with mature forest conditions. Also, there are no DNA sequences available for the species, and no phylogenetic studies have been conducted to test its phylogenetic position.

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Use and Trade

No use/trade is known.

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Source and Citation

Kossmann, T., Martins da Cunha, K., Seger, C. & Drechsler-Santos, E. 2021. Stropharia agaricoides. The IUCN Red List of Threatened Species 2021: e.T196136087A196846049. https://dx.doi.org/10.2305/IUCN.UK.2021-1.RLTS.T196136087A196846049.en .Accessed on 31 March 2024

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• Country occurrence