Comparison of habitats of the rare fungus Pluteus fenzlii between Białowieża Virgin Forest (Poland) and thermophilous forests (Slovakia)

Abstract Pluteus fenzlii is a rare Eurasian lignicolous fungus, an iconic bright yellow species that attracts attention. Its habitat in the Białowieża Virgin Forest, Poland, is dominated by Carpinus betulus with admixture of Quercus robur, Tilia cordata and Picea abies, with an herb layer typical for the Carpinion betuli alliance. In Slovakia, the country hosting the highest number of localities worldwide, P. fenzlii prefers closed canopy of thermophilous forest with dominance of Quercus cerris and adjacent Quercus robur agg., Q. petraea agg., Carpinus betulus and Tilia cordata. In the Natura 2000 classification this vegetation belongs to habitat 91M0, Pannonian-Balkanic Turkey Oak-Sessile Oak forests, and priority habitat 91G0, Pannonic woods with Quercus petraea and Carpinus betulus. The Slovak localities can be assigned to the mycosociological community Boleto (aerei)–Russuletum luteotactae, typical for thermophilous oak forests of Southern Europe and extrazonal areas in Central Europe. The presence of P. fenzlii at the isolated Białowieża locality could represent either a remote site of its present occurrence or a remnant of its former distribution, connected with the relict occurrence of thermophilous vegetation in Białowieża where continental oak forests have already disappeared.