Although considered as pioneering organisms of biocrusts, cyanobacterial biocrusts are scarce and even absent from the Namib fog belt, which is inhabited, however, by luxurious lichen-dominated crusts. While previously proposed that the phenomenon may stem from a low rainfall frequency, it is suggested herein that it may stem from a negative balance of carbon. This explanation is based on published data on photosynthesis of biocrusts along with an analysis of dew and fog formation. Lush cover of lichens at habitats with no cyanobacteria also casts doubt on the widely accepted view that regards cyanobacteria as a required component in biocrust succession. Biological soil crusts, Carbon balance, Lichens, Photosynthesis, Respiration, Succession