R-L categories correct, but text here does not match final assessment. Updated version will be published in IUCN´s Red List June or Nov 2019.
According to present knowledge, Hygrocybe punicea is a rare species distributed throughout most of Europe and Western Russia. It is also reported from North America, Canada, Australia and Asia (Japan, Korea, Asian part of Russia, etc.). Specimens of H. punicea throughout the whole distribution range should be studied by morphological and molecular taxonomic methods to find out whether they are conspecific. For now, the species is treated as distributed only in Europe.
It is an indicator of old, traditionally managed, semi-natural grasslands that are strongly declining. The main threats are habitat loss and decrease in quality due to land abandonment, changes in land use and pollution (nitrogen deposition). Modern agricultural methods include intensification of farming practices, increased use of fertilizers and/or pesticides, and plowing, all of which have an unfavorable effect on the populations of many valuable fungal species confined to semi-natural grasslands.
The estimated population size of this species exceeds 20,000 mature individuals in Europe, therefore criterion A is applicable. The projected reduction of the population is at least 30% over 30 years (past, ongoing and future) but may be even higher, up to 50% over three generations (50 years). Additionally, the decline in area and quality of semi-natural grassland habitats has exceeded 30% over the last 50 years. This meets the threshold IUCN category Vulnerable (VU) A2c+3c+4c.
Hygrocybe punicea has been reported from 31 European countries.
The species is confined to old, semi-natural grasslands in Europe. These habitats are traditionally managed by low intensity grazing and/or hand mowing. Intensfication of agricultural practices, grassland conversion and land abandonment are the main threats. Over the last century, more than 90% of semi-natural grasslands have been lost in Europe (EEA Report 3/2016). Available habitats for this species have continuously been lost during that time.
The population size of Hygrocybe punicea currently exceeds 20,000 mature individuals. The projected decline of its population across Europe is at least 30% over 30 years (past, ongoing and future). Even higher population decline is possible, up to 50% over three generations (50 years; e.g. 2000-2050). Over the last 50 years, the decline in area of semi-natural grassland habitats in Europe has exceeded 30%. The species is listed in many national fungal Red Lists in Europe.
Hygrocybe punicea is a characteristic species of old, unimproved, semi-natural grasslands in Europe. Only rarely it is found in other types of habitats (e.g. fixed dunes, deciduous woods). It occurs from lowlands up to 2350 m alt. in Alps.
Suitable grasslands are traditionally managed for a long period of time by grazing (by cattle, horses, sheep, deer) and/or regular hand mowing. These sites are characterized by low levels of available nitrogen and phosphorus in the soil and low vegetation. This species is a member of a specific fungal community occuring together with many rare and endangered macrofungal species, especially those from families Clavariaceae and Geoglossaceae, and genera Camarophyllopsis s. l., Hygrocybe s. l., Entoloma, and Dermoloma.
Hygrocybe s. l. species were considered as saprotrophs for a long time. Recently, Halbwachs et al. (2018) made an analysis of stable isotopes in fruitbodies of some Hygrocybe species to assess their trophic status. According to their research, Hygrocybe species are endophytes or could possibly form mycorrhizal relationships with plants.
Hygrocybe punicea is primarily threatened by degradation and loss of suitable habitats. Dominant trends in European semi-natural grasslands are decline in area, increasing fragmentation, and loss of diversity (Rounsevell et al. 2018). Traditional small-scale farming has decreased heavily in recent decades and many semi-natural grasslands were lost due to management intensification or abandonment (EEA Report 3/2016). The main agriculture-related pressures/threats to European grassland habitats are abandonment of traditional systems, lack of grazing and mowing, fertilisation, modification of cultivation practices, and agricultural intensification (EEA 2015). Fungal species that are characteristic of semi-natural grasslands are increasingly threatened by these practices and their populations are declining throughout the whole of Europe.
The most important actions needed for conservation of Hygrocybe punicea are the protection of semi-natural grasslands and their active management by traditional methods. The most valuable sites with high diversity of macrofungal species, especially from genera Hygrocybe, Entoloma, and Dermoloma, and from families Geoglossaceae and Clavariaceae should be protected in Europe. Some of these grassland sites are already integrated within protected areas but its management is not always adequate. Protected grasslands should be actively managed by extensive grazing (by cattle, horses, sheep, etc.) or regular hand mowing followed by sward removal (at least once or twice a year).
Besides Europe, Hygrocybe punicea is reported from North America, Canada, Australia and Asia (Japan, Korea, Asian part of Russia, etc.). However, some ITS sequences in Genbank obtained from North American specimens designated as H. punicea do not belong to the same biological species in the original sense (as in Europe).
Thorough taxonomic research based on morphological and molecular characters of H. punicea specimens from different continents is needed to find out whether they are all conspecific.
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