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, Cuphophyllus lacmus is a rare species reported in 17 European countries and Greenland. Around 400 occurrences of this species in Europe are listed in GBIF (2019) database with the largest populations recorded in the United Kingdom (212 occurrences), Norway (80), Denmark (46), and Sweden (32). The species is reported from North America and Japan (Boertmann 2010, GBIF 2019) also, but preliminary genetic analyses of North American material (Lodge & al. 2013) suggest that these collections belong to another (cryptic) species. For now, it is treated as distributed in Europe only.
C. lacmus occurs in semi-natural grasslands that are traditionally extensively managed by grazing (by cattle, horses, sheep, deer) and/or regular hand mowing (at least once a year) followed by sward removal. Its available habitats are heavily declining in Europe due to land abandonment and changes in modern agricultural practices including increased fertilization, use of pesticides, plowing, etc.
Total estimated population of C. lacmus is at maximum of 10.000 individuals. Its habitats, semi-natural grasslands, have also been threatened and are rapidly declining in area and quality throughout the whole of Europe (EEA Report 3/2016). Based on a decline of habitat quality and area, the projected population decline (past, ongoing and future) is at least 20% in 2 generations (30 years) or 30% in 3 generations (50 years). This meets the threshold for IUCN category Vulnerable (VU) A2c+3c+4c and C1.
According to Lodge & al. (2013) H. lacmus belongs to the genus Cuphophyllus and the correct name for this taxon is Cuphophyllus lacmus (Schumach.) Bon. Another taxon, C. subviolaceus (Peck) P.D. Orton et Watling described in North America, is often regarded as a synonym of C. lacmus. Preliminary genetic analyses of North American material (Lodge & al. 2013) suggest that these two taxa are not conspecific. Therefore, North American and other extra-European specimens identified as C. lacmus or C. subviolaceus should be compared with original European material by molecular and morphological methods. Until then, C. lacmus is treated as distributed in Europe only.
Camarophyllus lacmus (Schumach.) J. E. Lange
Hygrocybe lacmus (Schumach.) P.D. Orton et Watling
The species is reported in 17 European countries and Greenland.
The species is an indicator of old, extensively managed semi-natural grasslands in Europe. Non-European occurrences are excluded (see comment in Names and taxonomy section). It is currently reported in 17 countries. GBIF database (GBIF 2019) contains around 400 occurrences of this species in Europe with the largest populations recorded in the United Kingdom (212 occurrences), Norway (80), Denmark (46), and Sweden (32). The number of localities (including possible undiscovered localities) is estimated at a maximum of 1000. It is inferred that each population consists of 10 mycelia present on one locality (Dahlberg & Mueller 2011). The total inferred population in Europe is at most comprised of 10.000 individuals. More than 90% of semi-natural grasslands have been lost in Europe in the last century (EEA Report 3/2016). In recent times, these habitats have also been rapidly decreasing in area due to management intensification or abandonment throughout the whole of Europe (EEA Report 3/2016). Based on a decline of habitat quality and area, the projected population decline (past, ongoing and future) is at least 20% in 2 generations (ca. 30 years) or 30% in 3 generations (ca. 50 years). The species is listed in many national fungal Red Lists in Europe (e.g. Austria, Croatia, Czech Republic, Denmark, Germany, Netherlands, Switzerland).
Population Trend: Decreasing
Cuphophyllus lacmus occurs in unimproved, semi-natural grasslands, both on acidic and basic soils (Boertmann 2010), from lowlands up to 2300 m alt. in the Alps. Only rarely it is found in open woodlands. Suitable grassland habitats are those traditionally managed by grazing (by cattle, horses, sheep, deer) and/or regular hand mowing. These management practices maintain the low levels of available nitrogen and phosphorus in the soil needed for the existence of many rare and endangered fungal species associated with semi-natural grasslands. Grassland fungal communities with high conservation value are characterized by a great number of species from genera Camarophyllopsis s. l., Hygrocybe s. l., Entoloma, and Dermoloma, and families Clavariaceae and Geoglossaceae.
Hygrocybe species were mostly regarded as saprotrophic in the past. Recently, Halbwachs et al. (2018) made an analysis of stable isotopes in their fruitbodies and suggested that Hygrocybe s. l. species are either endophytes or possibly form mycorrhizal relationships with plants.
Cuphophyllus lacmus is threatened by fragmentation, degradation and loss of semi-natural grasslands in Europe. The main agriculture-related pressures/threats to European grassland habitats are abandonment of traditional management systems, lack of grazing and mowing, fertilisation, modification of cultivation practices, and agricultural intensification (EEA 2015). Fungal indicator species of valuable semi-natural grasslands are increasingly threatened by these practices and their populations have been decreasing throughout the whole of Europe. In contrast to traditional extensive management methods (grazing and/or hand mowing), the more recent intensification of farming has resulted in a dramatic decline of grassland biodiversity in other groups of organisms as well. A strong decline of grassland birds and a 45% decline in the butterfly population is reported in Western Europe in recent decades (Rounsevell et al. 2018).
The most important actions for conservation of Cuphophyllus lacmus are the protection of valuable semi-natural grasslands and their active preservation by traditional management methods. Criteria used for selection of high conservation value semi-natural grasslands should be richness and species composition of their CHEGD fungi (species of genera Hygrocybe, Entoloma, Dermoloma, and of families Geoglossaceae and Clavariaceae). Some semi-natural grasslands are already integrated within protected areas but management of these habitats is not always well suited to conservation of mycobiota. 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, Cuphophyllus lacmus is reported in North America and Japan (Boertmann 2010, GBIF 2019). Preliminary analyses of North American material (Lodge & al. 2013) designated as C. subviolaceus suggest that it is not conspecific with C. lacmus (in the original European sense). Morphological and molecular characters of available specimens from Japan and North America should be studied thoroughly and comparison with European material is needed.
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