Fig. 6.

Biological soil crusts and typical lichens. a–c Biological soil crust at Öland; b the green algal lichen Thamnolia vermicularis, arctic-alpine lichen; c Squamarina cartilaginea, boreal to mediterranean, element of colored soil lichen community; d–f Gössenheim, colored soil lichen community with Fulgensia fulgens (yellow), Psora decipiens (red–brown), Toninia sedifolia (grey), and cyanobacteria; e Cladonia foliacea, mediterranean element, and f Diploschistes muscorum, boreal to mediterranean; g–i cyanobacterial crust at Hochtor; h cross section of the upper part of the crust, several cyanobacteria embedded in a common sheath, Gloeocapsa spp. (reddish + blue), Nostoc sp. (brown); i Psora decipiens, at all four sites, boreal to mediterranean; j-l biological soil crust at Tabernas, Spain with Psora decipiens (pink) and Fulgensia bracteata (yellow); k Heppia despreauxii, xeric species (scale bar unit = 1 mm); l Acarospora nodulosa, lichenicolous on Diploschistes species, semi-arid to arid regions of Asia, North America, Europe, Africa, and Australia