Cryptobiotic soil crusts

Definition= A community of cyanobacteria (green algae, lichen, fungi and mosses) that form a fragile ground cover a few centimetres thick.

Found: Colorado Plateau & southwest USA (Account for >70% of the living ground cover)

Functions:

1) Important nurseries for seedlings
2) Slows run-off (rough surface)
3) Inputs organic matter (i.e. essential minerals) into the soil for plants.
4) Increase soil infiltration and absorb and stores rainwater (filaments of blue-green algae store up to 10 times their volume).
5) Bind together loose soil material from wind and water erosion (through dense network of filaments).

Human Impacts:

• Easily crushed and damaged (e.g. by vehicles, mountain bikes, hikers, livestock).
• Damage takes 50-250years for small areas to recover.
• Damaged crusts contribute less essential minerals.