Assessment Notes

Justification

Agrocybe elatella is saprotrophic fungus with its main distribution in Europe, preferring moderately nutrient-rich wetlands and marsh meadows, flat bogs and bog edges, spring slopes, sedge meadows, reed beds, marshes and fens, wet spots in extensively used lawns and other green areas (parks, cemeteries, gardens). It also grows in wet alder forest, less often in raised bogs and in pine forests. The species has been declining during the last decades years in central Europe due to habitat losses and changes, e.g. in Germany (Krieglsteiner 2003) and in Austria (Dämon and Krisai-Greilhuber 2017). It is severely threatened outside nature reserves due to the drainage of bogs, removal of reed belts and various other management changes. The habitat decline is ongoing and estimated to continue to decline in the future, so will the population size of the species. Based on the rate of habitat loss it is suspected that the population is undergoing a moderately rapid decline (20-30% over three generations) and so A. elatella is assessed as Near Threatened under criteria A2c+3c+4c.

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Geographic range

Agrocybe elatella is distributed in northern Asia (Caucasus, Siberia, Japan), and Europe (GBIF 2021); in Europe it is exceptionally distributed in southern (Spain, Italy), southeast (Romania), rare in western (Netherlands), central (Liechtenstein, Germany, Austria, Switzerland) and more widely in northern Europe (Hebrides, Shetland, Faroe Islands). Due to its special habitat requirements, it occurs everywhere only sparsely. The few records from Canada, the US and one from Taipei need to be confirmed and are not considered here.

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Population and Trends

Because mires, bogs and fens are wetland habitats with a high water content governing many ecological processes that structure their characteristic communities, their hydrological balance is easily disturbed by increased drainage caused by human activities. Furthermore, mire habitats have been widely destroyed or greatly altered in many areas by the extraction of peat. Extraction of peat and conversion of natural mire habitats to productive agricultural and forestry land have been the main reasons for the decline of mire habitats during recent and more long-term historic times and this decline is still continuing. In the EU countries, all but two of the 13 mire habitat types (85%) are threatened and this is the highest percentage of threatened habitats in all terrestrial and freshwater groups (Essl and Egger 2010, Janssen et al. 2016). These types of habitats are most vulnerable to hydrological system modifications, surface water and pollution (eutrophication), natural succession and erosion, agriculture intensification, silviculture and forest management, mining (peat extraction) and urbanization. They are also very sensitive to climate change, especially to increasing droughts.

According to the recent report by Barthelmes et al. (2015), in the Nordic-Baltic countries, the percentage of drained peatlands amounts to 44%, which is a rather low value compared to the total of Europe (almost 60%; Joosten 2009). Moreover, this rather positive picture compared to the rest of Europe is, however, attributable to only two countries, Norway and Sweden, in which less than 20% of the peatlands have been drained. Thus, a conservative estimate of the habitat loss for Agrocybe elatella within three generations approaches 30%; the rareness of this species and its dependence on the continuously declining habitat (both in the area and in quality) imply that A. elatella subpopulations have decreased in a similar range; and will continue to do so into the future.

Population Trend: decreasing

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Habitat and Ecology

The saprotrophic species prefers moderately calcium-rich wetlands and marsh meadows, fens, flat bogs and bog edges, spring slopes, sedge meadows, reed beds, marshes and fens, wet spots in extensively used lawns and other green areas (parks, cemeteries, gardens). It also grows in wet alder forest and in pine forests. It is moderately nitrogen-tolerant, but mostly occurs on nutrient-poor soils. It produces basidiomata early in the year, in early summer, rarely in autumn.

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Threats

Wetland sites are threatened by all actions leading to changes of hydrological regime in and around mires such as peat and moss extraction, drainage ditch digging, forestry plantations, eutrophication of groundwater, agricultural toxic discharges, urbanisation, and the intensive cattle grazing nearby the habitats. Such sites are also considered particularly vulnerable to climate change, in particular the impacts of droughts. The habitat of Agrocybe elatella is declining and is directly threatened by the above mentioned loss of bogs and wetlands, drainage, and lowering of the water table, which is still is ongoing and pronounced in central Europe but also ongoing in northern Europe.

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Conservation Actions

The species can be protected through habitat conservation and preventing the degradation of sites of actual and potential occurrence. This includes preventing changes in water regime, avoiding intensification of agriculture and silviculture practices in the neighbouring areas, control over peat extraction, active prevention of the forest succession and erosion, control over the practices leading to eutrophication etc., and designating key sites for protection. Inventories and monitoring of known sites and molecular taxonomic analyses are also needed to reveal the full distribution of the species.

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Use and Trade

The species should be edible, however, due to ist rarity, there is no use and trade known.

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Source and Citation

Brandrud, T.-E., Krisai-Greilhuber, I. & Kałucka, I.L. 2023. Agrocybe elatella. The IUCN Red List of Threatened Species 2023: e.T238739332A238779129. https://dx.doi.org/10.2305/IUCN.UK.2023-1.RLTS.T238739332A238779129.en .Accessed on 8 January 2025

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• Country occurrence