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.
Boletus dupainii is an ectomycorrhizal fungus with conspicuous red sporocarps associated with trees in the Fagaceae, typically Quercus. It is rare, but widespread in central-southern Europe and also reported from the Russian Caucasus and Turkey. The species is reported to decline in some countries and it is red-listed in most countries of occurrence. The conservation status of its most common habitat is reported as “unfavourable-inadequate”. Major threats relate to forest management and forest exploitation.
Red-listed as near threatened under criteria A2c+A3c because of past and future estimated habitat decline ca. 20 % in a 50-year period. Also under criteria C2a(i); the number of mature individuals is expected to be 20 000, with no subpopulation larger than 1000.
The taxon current names include Suillellus dupainii and Rubroboletus dupainii, with Boletus dupainii as basionym. Collections made in North and Central America under Boletus dupainii are not considered conspecific in this assessment.
Boletus dupainii is an ectomycorrhizal species associated with trees in the Fagaceac, typically Quercus. It is widespread in central-southern Europe and also reported from the Russian Caucasus, Turkey and Israel. The species has shown a decline in some countries and it is red-listed in most countries of occurrence. The conservation status of its most common habitat is reported as “unfavourable-inadequate” based on future prospects. Major threats relate to forest management and forest exploitation.
Red-listed as near threatened under criteria A2c+A3c, because of past and future estimated habitat decline ca. 20 % in a 50-year period. Also under criteria C2a(i); the number of mature individuals is expected to be 20 000, with no subpopulation larger than 1000.
Widespread in central-southern Europe (absent from the UK and Scandinavia). Also reported from the Russian Caucasus (Krasnodar Kray) and Turkey.
Overall rare, though more abundant in southern European countries (France, Slovenia). The compilation of the distribution and frequencies of a selection of 51 European macrofungi reported the number of known sites to be around 100, of which more than 50 in France and Italy (Fraiture & Otto, 2015). Although B. dupoinii´s potential habitat is large, it is such a conspicuous, well-known and easily identifiable fungi that it is not considered to be much overlooked. It has a large distribution and the total number of locations is estimated to be significantly higher, but not to exceed 1000. With an average 1-2 genetically unique mycelia at each location, the total number of mature individuals will not exceed 15000. The habitat of B dupoinii is assesses as to have decline with more than 20% during the last 50 years and the decline is projected to be similarly in size the forthcoming 50 years (cf, European Commission, 2015). Ectomycorrhizal fungi are assessed by a 50 year time period as that corresponds to three generations (Dahlberg & Mueller, 2011).
The most common habitat of Boletus dupainii is “Medio-European limestone beech forests of the Cephalanthero-Fagion” (Natura 2000 code 9150, France, Germany, Slovakia, Slovenia). According to the last report under Article 17 of the EU Habitats Directive (European Environmental Agency, 2007-2012) the conservation status of this habitat is “unfavourable-inadequate” and in all regions except Mediterranean, “unfavourable-bad” and Pannonian “favourable”. Range and area are “favourable” in all regions and both structure & functions and future prospects are the reason for the “unfavourable” assessments.
The mid-term review of the EU biodiversity strategy towards to 2020 (European Commission, 2015) indicates a “decrease in habitat change” in woodland ecosystems as the future trend, but also specifies that the vast majority of assessments of conservation status for woodlands remains “unfavourable” (80 %). The majority of the assessments of conservation status for woodland and forest species from the Habitats Directive are “unfavourable”, with 44% assessed as “unfavourable-inadequate” and 16% assessed as “unfavourable-bad”. As for the trends in conservation status of (target) species, nearly a quarter of the assessments are assessed as “unfavourable-stable” (22%), while only 6% are assessed as “unfavourable-improving”; a significant amount of the remaining assessments (17%) are assessed as “unfavourable-declining” (European Environmental Agency, 2015).
Population Trend: Decreasing
The species mainly occurs in termophilous deciduous natural or semi-natural forests dominated by Quercus, often old-growth, sometimes preferring more open areas. It is ectomycorrhizal with trees in the Fagaceae, typically Quercus (e.g. Q. cerris, petraea, pubescens, suber, ilex, rotundifolia), but also Carpinus, Fagus and Castanea. Often accompanied by other Boletales species (B. fechtneri, B. lupinus, B. rhodoxanthus). Due to global warming effect it is expected to slowly spreading northwards, to potentially developing suitable habitats in oak and beech forests of Central Europe. The species occurs in the following Natura 2000 habitats (codes): 9150 (“Medio-European limestone beech forests of the Cephalanthero-Fagion”; the most common habitat), 9160, 9170, 91G0, 91H0, 91M0, 91AA, 9330, 9340.
Threats mainly relates to forest management (e.g., fire, clearcutting; Fraiture & Otto 2015). Habitats may be irreversible destroyed due to the substitution of native oak forests by conifers (e.g. Pinus nigra) and spreading of the invasive alien species Robinia pseudoacacia.
The species is red-listed or protected by law in most of the countries where it occurs. For the sites that are within the Natura 2000 network, appropriate forest management plans can play a role in increasing the conservation status of the species. For the localities located outside protected the Natura 2000 network, improving EU-level information on forest status will allow a more precise assessment of the situation and the design of appropriate policy responses. Individual mycelia of ectomycorrhizal fungi may potentially become very old, several decades and potentially centuries with a continuous presence of their host trees. Therefore, site protection, considering with long term management if needed to maintain the habitat, will often secure long-time survival.
Records in North and Central America need confirmation for conspecificity. There are two sequences (ITS) of Rubroboletus dupainii, the European Boletus dupainii, and sequences from North America (tef1). However, because different loci were used comparisons aren’t possible. Boletus reichertii described from Israel seems very close to Boletus dupainii and needs further study.
Dahlberg A. & Croneborg H. 2006. The 33 threatened fungi in Europe. Nature and environment, No. 136. Council of Europe Publishing. ISBN-10: 92-871-5928-9; ISBN-13: 978-92-871-5928-1
European Commission. 2015. The mid-term review of the EU biodiversity strategy to 2020. Report from the Commission to the European parliament and the Council. Brussels. (summary at http://ec.europa.eu/environment/nature/biodiversity/comm2006/pdf/mid_term_review_summary.pdf)
European Environmental Agency. 2007-2012. 9150 Medio-European limestone beech forests of the Cephalanthero-Fagion. Report under the Article 17 of the Habitats Directive European Environment Period 2007-2012. Accessed on February 2018 at https://bd.eionet.europa.eu
Fraiture A. & Otto P. (eds) 2015. Distribution, ecology and status of 51 macromycetes in Europe. Results of the ECCF Mapping Programme. Scripta Botanica Belgica 53, Botanic Garden Meise.
GBIF website at https://www.gbif.org/ Accessed 20 February 2018.