Hygrocybe spadicea is assessed as Endangered (A4c) based on a suspected, continuing decline of approximately 60% in three generations (50 years).
Hygrocybe spadicea is variable in some characters. Next to var. spadicea with bright yellow lamellae, var. albifolia is distinguished with white lamellae. See photograph 1 from Sweden. In view of research in other species complexes of Hygrocybe it is unlikely that the few records of H. spadicea from North-America and New Zealand represent the same biological species as in Eurasia. These records are not considered here.
Hygrocybe spadicea is a well-characterized waxcap with a brown, conical to umbonate pileus, contrasting with the yellow stipe and lamellae. The species is characteristic for grass-heaths on dry, very poor, acidic to weakly acidic soil and for limestone-grasslands, in Europe priority plant communities in the Natura2000 network that are strongly declining allover Europe. The species has a wide distribution, but it is rare to very rare everywhere (Boertmann, 2010) and decreasing; reason why it is included in numerous national Red Lists.
Europe, Central Asia, from the lowland to the subalpine zone. Possibly also in a few places in North-America and New Zealand,
Hygrocybe spadicea is widespread in Europe, but (very) rare on very scattered localities throughout its range (Boertmann, 2010). Populations are usually very small (1-5 mycelia) and fruiting irregularly. Populations are strongly declining, reflected in its position on many national and regional Red Lists, e.g. Regionally extinct in Poland and Estonia; Critically endangered in Finland, Baden-WÃ¼rttemberg and Niedersachsen; Endangered in Croatia, France, Norway, Germany, Austria and Switzerland; Vulnerable in Sweden; Near threatened in Denmark. H. spadicea is absent from the Netherlands and FLandres. In view of the strong decrease of the surface of old, well-developed grass-heaths throughout Europe, the decline of H. spadicea is estimated at more than 50% during the last 50 years (three generations of this fungus). The decrease is still continuing. In North-America H. spadicea is reported as very rare on very few, scattered localities (Hesler & Smith, 1963; Bessette et al., 1997), but they are regarded here as doubtful (see remarks on taxonomy). Data on the trends in North-America are unknown.
Population Trend: Deteriorating
In Europe Hygrocybe spadicea is a characteristic species of ancient, unimproved, low productive grass-heaths on very poor, acidic, sandy or loamy soils and on shallow, calcareous soils above limestone. It has a preference for dry, exposed slopes in hilly or mountainous areas (Boertmann, 2010). It ususally occurs in sites with a rich mycoflora, including many other rare and threatened species. Like other waxcaps H. spadicea probably lives in biotrophic association with herbaceous plants, but details on its habitat exploitation are unknown. In North-America it also is reported from scrub and frondose forests (Hesler & Smith, 1963).
The main threat to Hygrocybe spadicea is loss of habitat by changing land use, including grassland improvement by ferlilizer application and conversion into monocultures for agro-industry; abandoning of seminatural grasslands, followed by natural succession to scrub and forests; forest plantations; inappropriate management, also in protected sites (under- or overgrazing; mowing without removal of the sward, etcetera). In addition the species is threatened by acidification and nitrogen deposition, also in protected areas.
Protection of sites of this species, in particular those with good and regularly fruiting populations, as nature reserves. Continuation of extensive grassland management is essential. The species would benefit from a reduction of air pollution (nitrogen deposition).
More detailed knowledge of the ecological range and characteristics of the habitat, e.g. concerning critical load of nitrogen. Taxonomic research, including molecular characters, of populations in Europe, North-America and New-Zealand to find out whether they are conspecific.
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Bessette, A.E., A.R. Bessette & D.W. Fischer. 1997. Mushrooms of Northeastern North America.
Boertmann, D. 2010. The genus Hygrocybe.
Candusso, M. 1997. Hygrophorus sl. Fungi Europaei 6.
Hesler, L.R. & A.H. Smith. 1963. North American species of Hygrophorus.
Krieglsteiner, G.J. 2001. Die Grosspilze Baden-Württembergs 3.