Fungi associated with biological soil crusts in desert grasslands of Utah and Wyoming

Biological soil crusts of arid and semiarid regions of the world are recogn ized as one of the least explored niches occupied by fungi. The principal s pecies of fungi associated with biocrusts in desert grasslands and their as sociated soils in two geographically separated sites were identified and co mpared with species from a similar community in which the active crust had been destroyed by grazing. The results confirm the existence of a highly di verse and to some degree a host specific assemblage (mycosociety) of fungi. Comparison of the prevalent species by presence and commonness at the undi sturbed and disturbed sites revealed both quantitative and qualitative chan ges. The forms absent or with a markedly reduced occurrence in the disturbe d site were three dark-colored anamorphs of loculoascomycetes (Bipolaris sp ., Embellisia tellustris, Phoma anserina) and two loculoascomycetes (Graphy llium permundum, Pleospora richtophensis). Fungi present at all sites inclu ded Chrysosporium/Geomyces pannorum, Embellisia tellustris and Pseudozyma s p. Crust associated fungi not previously reported from soil included a basi diomycete (Cyphellostereum sp.), five loculoascomycetes (Kalmusia utahensis , Macroventuria wentii, Pleospora richtophensis, Phaeospora sp., Preussia s p.) and three mitosporic species (Heteroconium sp., Sclerococcum sp., Taeni olella sp.). Overall, the commonly encountered crust-associated fungi were dark-colored mitosporic and sterile forms apparently adapted to desert envi ronments.