Pulchroboletus roseoalbidus is an ectomycorrhizal fungal species, rather rare confined to the Mediterranean area of Europe. It grows solitary or more often caespitose in poor dry habitats at the border or in open areas of thermophilous broadleaved forests, preferring deciduous but observed also in evergreen oak woods.
The species has a restricted range and grows in small scattered localities. Described on first findings from Sardinia island as new for science in 1987, the species was then found rarely but in various different localities, from continental Italy to the west to Corsica and Spain, to the east till Greece and Bulgaria. The largest number of records came from Italy with about 40 known records.
The total population size is estimated as 5,500-11,000 mature individuals, most of the records are of less than 10 mycelial individuals (2-6 genets). Population reduction has been observed and will continue into the future given that the main threats are changing of management (few thinning with the loose of open areas or clearcutting and wood harvesting), fire, and habitat degradation due to anthropogenic activities, but also deseases of woods itshelf, like the chestnut coppices.
Pulchroboletus roseoalbidus qualifies for listing as Near Threatened under criterion C2a(i) as its total population size is estimated to be under 20.000, with less than 2000 mature individuals in the largest subpopulation and population decline.
Pulchroboletus roseoalbidus (Alessio & Littini) Gelardi, Vizzini & Simonini, in Gelardi, Simonini, Ercole & Vizzini
Boletus roseoalbidus (Alessio & Littini) G. Moreno & Heykoop,
Rubinoboletus roseoalbidus (Alessio & Littini) De Kesel
Xerocomus roseoalbidus Alessio & Littini
Pulveroboletus albopruinosus Cetto & Zucch
First observed on the island Sardinia in 1986, it was described as uncommon growing at the edge of deciduous woods in more open areas in extremely arid climatic conditions. This ectomychorrizal species with pileus pale-pink changing to intense pink or purple colour depending on humidity, often with granulous ring-zone in the upper half of the yellow stipe, prefers as host tree oaks and can be find from the sea level up to submontane areas. The distribution is not well known but the observations are increasing and it results present in various countries in southern Europe. Precise studies must be done but presumibly the species can be assessed as NT.
The distribution is not well known but the observations are increasing and it results present in various countries in Mediterranean area of Europe.
The total population size is estimated as 5,5000 - 11,000 mature individuals, most of the records are of less than 10 mycelial individuals (1-2 genets). Population reduction has been observed and will continue into the future given that the main threats are changing of management (few thinning with the loose of open areas or clearcutting and wood harvesting), fire, and habitat degradation due to anthropogenic activities. Moreover the chestnut coppices where the species was rarely found, are threatened by deseases itshelf (Phytophthora cambivora, Cryphonectria parasitica, and the recently arrived Dryocosmus kuriphilus).
Localities - 2 Spain, 6 Greece, 4 Bulgaria, 1 France, and most in Italy with 40, so nearly 55 ‘known’ localities x maximum 10 mature individuals per site [distinctive, so probably difficult to overlook] so x 10 for potential unfound sites, which gives about 5500 mature individuals x1-2 = 5,500-11,000
Population Trend: Decreasing
This ectomychorrizal species grows in more open areas or at the edge of woods in extremely arid climatic conditions, on basic and weakly acid to acid soils. Pulchroboletus roseoalbidus prefers oaks (Quercus cerris, Q. coccifera, Q. ilex, Q. pubescens, Q. robur, Q. suber, Q. ithaburensis ssp. macrolepis) but can be found also with chestnut (Castanea sativa) from the sea level up to submontane areas principally in the central mediterranean zone, and reach the Black Sea Coast (Northern Bulgaria), In addition there is an interesting observation of this autoctonous ectomycorrhizal species with the non-native to Europe Quercus rubra in South Bulgaria (Bozoc et al, 2019).
However the species appears to display a narrower distribution in relation to its potential geographic range.
The species has more or less similar habitats and phenolody as Alessioporus ichnusanus assesed as vulnerable (Persiani, 2019 in The IUCN Red List of Threatened Species). In Tuscany (Italy) P. roseoalbidus was assessed as VU (Antonini D., Antonini M. , 2006), and recently also as VU in central Italy (Wagensommer et al., in print), The threats for this species preferring host trees like oaks, is the past replacement of broadleaf woods by pine monocultures, changing management, and the increasing agriculture and urbanization. The redlist of Bulgaria assessed the species as EN (Gyosheva et al., 2006) due to limited distribution, forest cutting, and habitat loss as a result of the intensive tourism and infrastructure development. Moreover fruiting bodies are often severely damaged or destroyed by the parasitic fungus Sepedonium chrysospermum. Among the host trees there is also Castanea sativa, and the deseases or illness of chestnut coppices due to at least 3 different pathogenic agents could be another threat.
The increasing observations in southern Europe brought to increasing knowledge and it can maybe be considered as NT.
Limiting agricultural landuse and pine plantations, limiting the spread of exotic trees like Robinia pseudoacacia or Ailanthus altissima.
Finding a solution to the phytosanitary problems of Castanea sativa.
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