• Proposed
  • Under Assessment
  • Preliminary Assessed
  • Assessed
  • VUPublished

Hygrocybe citrinovirens (J.E. Lange) Jul. Schäff.

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Scientific name
Hygrocybe citrinovirens
Author
(J.E. Lange) Jul. Schäff.
Common names
Citrine Waxcap
grøngul vokshat
Limettivahakas
lúčnica citrónovožltá
IUCN Specialist Group
Mushroom, Bracket and Puffball
Kingdom
Fungi
Phylum
Basidiomycota
Class
Agaricomycetes
Order
Agaricales
Family
Hygrophoraceae
Assessment status
Published
IUCN Red List Category
VU A2c+3c+4c
Proposed by
Ivona Kautmanova
Assessors
Ivona Kautmanova
Contributors
Ivona Kautmanova, Tommy Knutsson, Thomas Læssøe, Tea von Bonsdorff
Comments etc.
Michael Krikorev

Assessment Status Notes

Taxonomic notes

Hygrocybe virescens from North America is similar and may be conspecific.


Why suggested for a Global Red List Assessment?

Hygrocybe citrinovirens is one of the best indicator species of species-rich semi-natural grasslands which were for a long time managed in a traditional way, so called waxcap grasslands.  These habitats, dependent on moderate grazing intensity and/or hand mowing without using artificial fertilizers and pesticides, are rapidly disappearing worldwide and so do fungal species bound to them.
H. citrinovirens is a large, conspicuous and easy to recognize and have relatively low dark figures when it comes to number of localities. Its not known outside Europe (but have close relatives in North America) and its populations are decreasing in all countries where it occurs. Redlisted in seven european countries.
Preliminary global red-list assessment; NT close to VU (A2c+3c+4c), habitat decline in area and quality approaching/exceeding 30 % during the last 30 years and estimated population decline is probably higher. This decline of the habitat quality is expected to continue even more rapidly in the next 50 years. The past, ongoing and expected decline may exceed 30%, if so VU. Evaluation period (= 3 generations) is considered to be 50 years for H. citrinovirens as recommended for ectomycorrhizal and soil inhabiting species by Dahlberg & Mueller (2011). Norwegian redlist estimated generation time only 17 years.
The species has a Europan population that probably exceeds 20 000 mature individuals. 
Cause of decline: Loss of suitable habitat due to changes in landuse, i.e. agricultural intensification and decline of traditional farming (hand mowing and grazing) as well as application of fertilizers and pesticides.


Geographic range

Hygrocybe citrinovirens is so far only known from Western palearctic (eastwards to Georgia). Reported from most European countries and stronghold occurences probably situated in NW Europe.
Hygrocybe virescens from North America is similar and may be conspecific.


Population and Trends

Population probably exceeding 20 000 mature individuals but is decreasing in all known countries of occurence, caused by lack of small scale farming and traditional ways of grassland management. the decrease is casually estimated to 30% (past, future and ongoing) but might actually be as high as 50% considering a 50y period (e.g. 1975-2025) and even higher considering other time-scales and periods.

More than 75% of the grasslands habitats in EU are in an unfavourable conservation status, according to draft data provided by Member States under Article 17 of the Habitats Directive. Over the past decade, grassland butterflies have suffered large declines in Europe, with a reduction of abundance by almost 50%, with little sign of improvement (http://ec.europa.eu/environment/nature/biodiversity/comm2006/pdf/sebi_full.pdf).

Population Trend: Deteriorating


Habitat and Ecology

Hygrocybe citrinovirens is confined to seminatural, herb-rich grasslands, both on calcareous and more siliceous soils, Earlier considered to be saprotrophic but recent research have shown that some (and probably all) Hygrocybe species have arbuscular mycorrhiza connected to vascular plants. The species is a representative of a fungal community with a large diversity other fungal species (Hygrocybe spp., Entoloma spp,, Clavaroid fungi, Geoglossaceae and many other fungi strictly dependent on habitats with low vegetation and limited availability of phosphorus and other nutrients due to long continuity of grazing and/or mowing. Added fertilizers or abandonment immediately changes vegetation cover in a way that is detrimental for the fungus community.

The species is more or less confined to the following habitats:
6210 NATURA 2000 - Semi-natural dry grasslands and scrubland facies on calcareous substrates (Festuco-Brometalia)
6230 NATURA 2000 - Species-rich Nardus grasslands, on siliceous substrates in mountain areas and submountain areas.

Temperate Grassland

Threats

Like other species dependent on semi-natural grasslands Hygrocybe citrinovirens it is threatened by the loss of habitat due to decreasing small scale farming. The main reasons for decline are agricultural intensification (primarily the application of phosphorus) and the reduction of habitat areas and quality. Grassland neglect where the sward becomes rank and overgrown also restricts carpophore production, although it is not clear if this affects the mycelium under the ground. In urban/suburban environment, the application of lawn fertilisers, fungicides and moss killers can also affect the species (Mitchel 2000).

According to NATURA 2000 reports (Calaciura & Spinelli) grassland habitats is steadily decreasing, mainly due to abandonment or change in landuse. The total area of grassland in the EU fell by an average of 12% between 1975 and 1998, with increases in only very few areas. In the areas where the habitat is still present, the lack of management results in a continuing decrease in range of many species due to decrease in habitat quality.
According to FAO the area of grasslands in the EU declined by 12.8% from 1990 to 2003; only a few Member States managed to buck this trend. (Food and Agricultural Organisation of the United Nations 2006: FAO Statistical Yearbook. – FAOSTAT). Pressure caused by landuse changes on grassland habitats is steadily increasing. Some 60% of newly afforested areas in the EU was formerly used as permanent/seasonal grazing land or hay-production in natural meadows.

More than 75% of the grasslands habitats in EU are in an unfavourable conservation status, according to draft data provided by Member States under Article 17 of the Habitats Directive. Over the past decade, grassland butterflies have suffered large declines in Europe, with a reduction of abundance by almost 50%, with little sign of improvement (http://ec.europa.eu/environment/nature/biodiversity/comm2006/pdf/sebi_full.pdf).

Housing & urban areasAgro-industry farmingAgro-industry grazing, ranching or farmingNutrient loadsHerbicides and pesticides

Conservation Actions

Site protection and management of habitats is very important conservation actions. Some grasslands with high species diversity and conservation values including grassland fungi such as Hygrocybe citrinovirens communities are situated within national parks, nature monuments or nature reserves. However, these grasslands needs careful management plans including grazing which is not allways present even within strictly protected areas. This situation results in continual decrease of habitat quality even if sites protected from exploitation.

Site/area protectionSite/area managementHabitat & natural process restorationConservation payments

Research needed

Distribution is not well known in south-eastern Europe.

Population size, distribution & trendsHabitat trends

Bibliography

Adamcik, S. & Kautmanova, I. 2005. Hygrocybe species as indicators of natural value of grasslands in Slovakia. Catathelasma, 6:25-34.
Calaciura & Spinelli. 2008. MANAGEMENT of Natura 2000 habitats * Semi-natural dry grasslands (FestucoBrometalia) 6210. NATURA 2000. technical Report 2008 12/24. http://ec.europa.eu/environment/nature/natura2000/management/habitats/pdf/6210_Seminatural_dry_grasslands.pdf
Candusso, M. 1997. Hygrophorus s. l. [Fungi Europaei, vol. 6]. Alassio, Edizioni Candusso.
Evans, S. 2003. Waxcap-grasslands – an assessment of English sites. English Nature Res. Rep. (555).
Griffith, G. W., J. H. Bratton & G. Easton. 2004. Charismatic megafungi – the conservation of waxcap grasslands. Brit. Wildlife 16(1): 31-43.
Boertman, D. 2010. The genus Hygrocybe. 2 nd revised edition. Fungi of Northern Europe. vol 1. 200 pp.
Jordal, J. B. 1997. Sopp i naturbeitemarker i Norge. En kuunskapsstatus over utbredelse, okologo, indikatorverdi og trusler i et europeisk perspektiv. Utredning for DN 1997-6. Trondheim, Direktoratet for Naturforvaltning
Mitchell, K. 2000. The culture of urban space. URBAN GEOGRAPHY 21 (5): 443-449.
Wojewoda, W. 2003. Checklist of Polish larger Basidiomycetes. Polish Academy of Sciences, p.308
Kovalenko, A.E. 1989. Ordo Hygrophorales. Definitorium Fungorum URSS. Nauka, Leningrad, 172 pp.
Uzelac, B. 2009. Gljive Srbije i zapadnog Balkana.BGV Logik,462 pp.
Webpages:
http://ec.europa.eu/environment/nature/biodiversity/comm2006/pdf/sebi_full.pdf


Known distribution - countries

Regional Population and Trends

Country Trend Redlisted