The contribution and importance of rare macrofungi in selected plots of endangered xerothermic grasslands in the Nida Basin

Xerothermic habitats of protected sites in the Nida Basin are of special natural value. The richness of steppe plant species contributes to the biodiversity of grassland ecosystems and increases the floristic and landscape uniqueness of Ponidzie. A rich thermophilous biota of interesting steppe macromycetes (Basidiomycetes) develops in the xerothermic vegetation in the area. As preliminary investigations into macrofungi in xerothermic communities in the Nida Basin have shown, many very rare and valuable species as well as species new to the Polish mycobiota occur in the study area. Several rare species of gasteroid fungi, such as Geastrum minimum and G. schmidelii, were found in patches of Sisymbrio-Stipetum capillatae. Many taxa are indicator species of these biocoenoses. Noteworthy are parasitic macrofungi infecting roots of the genus Stipa: Gastrosporium simplex and Polyporus rhizophilus. Localities of species of the genus Tulostoma: T. brumale, T. kotlabae and T. melanocyclum, T. squamosum, new to the Nida Basin, were recorded in patches of Koelerio-Festucetum rupicolae and Festucetum pallentis. The above fungi are very rare in Poland’s mycobiota. They are strongly threatened and are classified as endangered (E). Geastrum minimum and the species of the genus Tulostoma are strictly protected