Jayne Belnap Belnap clearly describes the importance of biological soil crusts in the desert in her article “Soils and Cryptobiotic Crusts in Arid Lands" found on the U.S. Geological Survey’s website.

• "Cryptobiotic crusts are important features of arid and semiarid ecosystems throughout the Southwest, including pinyon pinyon-juniper woodlands and deserts"
  
• "Living soil crusts in deserts are composed primarily of blue-green algae and secondary components include soil lichens, mosses, green algae, microfungi, and bacteria."
  
• With moisture, blue-green algae moves across the soil leaving a fibrous sheath behind. This sheath binds loose soil particles and/or rocks together.
  
• Soil erosion due to wind and water forces becomes less probable as sheaths build up atop soil surfaces over time.
  
• With the ability of sheaths to absorb up to 10 times their volume of water, they facilitate a slow release of water into the soil and hold water that would have otherwise become runoff.
  
• Clay particles, the smallest of soil sizes, aggregate on sheaths. The clay particles hold essential nutrients for plant growth, contributing to the health of plants.
  
• The blue-green algae, soil lichens, mosses, green algae, microfungi microfungi, and bacteria add organic matter and nitrogen to the soil - much needed components of desert plant survival.
  
• Once soil crusts are disturbed they are more prone to wind and water erosion, and may take years to recover, if they can recover at all.

More information can be found at Soilcrust.org