Also called microbiotic, microphytic, cryptobiotic or cryptogamic crusts. A living community of
bacteria, microfungi,
cyanobacteria, green
algae, mosses,
liverworts, and lichens that grow on or just below the soil surface. Biological crusts can heavily influence the morphology of the soil surface, stabilize soil, fix carbon and nitrogen, and can either increase or decrease
infiltration. The percent cover and the components of the crust can vary across short distances. Identification of biological crust organisms is simplified through the use of three broad morphological groups: The
cyanobacteria group includes
cyanobacteria and green
algae. The
moss group includes short and tall mosses, but not club
moss mats, such as those in northern latitudes, or spike
moss. The
lichen group includes crustose, gelatinous, squamulose, foliose, and fruiticose
lichen, as well as
liverworts.