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.
Clavaria zollingeri is rare and strongly confined to semi-natural grasslands. Griffith et al. (2013) estimated a habitat loss of 90% over the last 75 years for the CHEG-fungi (grassland fungi of the groups Clavariaceae, Hygrocybe s.l., Entoloma and Geoglossaceae) as a whole in Western Europe (i.e. loss in seminatural grasslands, based on available information). These habitats are declining and getting bad quality due to changing agricultural practices, development projects and pollution (nitrogen deposition). GBIF lists about 1100 occurrences in areas where the species is assumed to occur. The species is assumed to have a population of more than 20000 mature individuals, and the A-criterion is thus appropriate. In Europe, the habitat loss and population decline is assumed to be 30-50% in 50 years (past, present and future) (approximately three generations: one generation is assumed to be about 17 years). Habitat quality has also become impaired and the decline in population size over this time could be even higher. This decline in habitat is ongoing and expected to continue over the next 50 years. The species meets the threshold for VU (A2c+3c+4c) in Europe (probably near EN), which is also assumed to be the total area of the species.
In GBIF (2019), Eurasian, American and Australian collections are treated as one species. This is probably not true, as there are indications that different parts of the world have different species. In the meantime until this is clarified, we choose to treat European populations of what has been called Clavaria zollingeri as one species. The identity of Clavulina amethystina ss. auct. is unclear, but this name is sometimes probably used about Clavaria zollingeri.
Clavaria zollingeri is treated here as a European species (see notes on taxonomy). It is considered a flagship species of threatened grassland Clavaria spp., inhabiting old, species rich semi-natural grasslands which were for a long time managed in a traditional way, so called waxcap grasslands (Jordal 1997, Boertman 2010). These habitats are strongly declining due to agricultural intensification (plowing, use of fertilizers and pesticides), development projects, and aerial nitrogen deposition. Redlisted in many countries.
GBIF-data from Asia, N America and Australia are excluded as probably other species. Our species occurs in most European countries as shown on the map. It occurs from lowland up to subalpine areas.
According to GBIF (2019) there are about 1100 occurrences from Europe. Many of these are probably duplicates from the same localities, but the database also lack much information, so the number of known localities in Europe is assumed to be more than 1000. Seminatural grasslands are strongly declining. Based on available information on trends in seminatural grasslands, Griffith et al. (2013) estimated a habitat loss of 90% over the last 75 years for the CHEG-fungi (grassland fungi of Clavariaceae, Hygrocybe s.l., Entoloma and Geoglossaceae) as a whole in Western Europe. According to the Food and Agriculture Organization of the United Nations (FAO), the area of grasslands in the EU declined by 12.8% over 13 years (1990-2003). Also other sources point to a habitat loss in seminatural grasslands of roughly 1% per year in Europe over a longer time, although the data quality is not always very good. Over the whole distribution range we assume a minimum habitat loss and population decline of 30%-50% over the last 50 years, while the seminatural grasslands of north European lowlands could have declined more than 50% over the same period. As the habitat quality of seminatural grasslands is also declining, population decline could be higher, and strengthen the assumption of a population decline above 50%. More than 75% of the grasslands habitats are in an unfavourable conservation status, according to draft data provided by Member States under Article 17 of the Habitats Directive (http://ec.europa. eu/environment/nature/knowledge/ rep_habitats/index_en.htm#csa). This trend is ongoing and expected to continue in the future.
Population Trend: Decreasing
The species is an indicator of old unfertilised grasslands, growing in mycologically rich but nutrient-poor semi-natural grasslands, often on acid soil. Habitat preferences are that the grass sward is usually short, moss rich and poor in nutrients (Mitchell 2000). Czech Republic: There are actually more collections from lawns in old parks and gardens than in pastures or grasslands (Daniel Dvořák). In Norway, the habitat specificity has been quantified: N=235; 87,7% in seminatural grasslands, and 11,1% in rich forests (Jordal et al. 2016), and similar patterns are found in many other European countries. The nutrient strategy is unknown but it could have some kind of biotrophy or mycorrhiza, like waxcaps (Griffith 2004).
Habitat destruction and abandoning are the main threats to seminatural grasslands. The most important process is probably withgrowing due to ceased grazing/mowing of old seminatural grasslands as part of intensification of agriculture. Modern cultivation methods are important threats like use of fertilizers, pesticides and plowing. Also some places the use of the areas is changing, with the construction of roads, industrial areas, settlements etc. Decline is expected to continue, as at least the areas of seminatural grasslands are of little economic importance in modern agriculture. Most CHEG grasslands (see Population and trends) are among types redlisted as VU, EN or CR in the EU red list of habitats (Jansen et al. 2016). In the urban environment, the application of lawn fertilisers, fungicides and moss killers can also affect the species (Mitchel 2000). According to NATURA 2000 reports (Calaciura & Spinelli 2008), pressure on grassland habitats is steadily increasing, mainly due to abandonment or change in use.
Some of the grasslands are already protected by law as Natural monuments, Natural reserves a.o. Some of the grassland fungal species are redlisted or protected by law. Some countries have selected priority species (cf. Mitchel 2000). The main focus is to maintain the number of viable populations of this species. The habitats should be protected against destruction due to intensification of agriculture or development plans. The maintaining of seminatural grasslands demands yearly grazing or mowing. If grazing by heavy animals destroys part of the soil, light animals like sheep should be recommended. Habitat conservation by governmental support to traditional agricultural practices is most important, this exists in many countries to maintain extensive areas of agricultural areas, and should be extended to larger areas than today.
Research into ecological requirements and trophic form. Management plans are needed. Habitat trends should be monitored. Despite the importance of this conspicuous species in many inventory and biodiversity research projects, very little is still known about its taxonomy. More molecular and taxonomical investigation is necessary to know which species are present and where.
The species is not known to be used.
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