Biological soil crust

Biological soil crust
Cryptobiotic soil, cryptogamic soil, microbiotic soil, microphytic soil, biocrust
Biological soil crust in Hovenweep National Monument.
Climate	arid, semi-arid
Primary	fungi, lichens, cyanobacteria, bryophytes, and algae

Biological soil crusts are communities of living organisms on the soil surface in arid and semi-arid ecosystems. They are found throughout the world with varying species composition and cover depending on topography, soil characteristics, climate, plant community, microhabitats, and disturbance regimes. Biological soil crusts perform important ecological roles including carbon fixation, nitrogen fixation and soil stabilization; they alter soil albedo and water relations and affect germination and nutrient levels in vascular plants. They can be damaged by fire, recreational activity, grazing and other disturbances and can require long time periods to recover composition and function. Biological soil crusts are also known as biocrusts or as cryptogamic, microbiotic, microphytic, or cryptobiotic soils.