10/13/2026
This is why it is so important to stay on trails when hiking in the desert! The soil is a fragile living thing here and breaking the crust can lead to lots of dust and erosion among other issues that keep the habitat in good health.
Biological soil crust is found throughout the world, but especially in arid places like deserts. This living micro-ecosystem contains moss, lichens, algae, fungi, bacteria, and cyanobacteria! These organisms work together in a few different ways.
First, the crust stabilizes the top layer of soil, keeping it from blowing away like sand dunes. These organisms clump together with the sand, reducing erosion from wind and water.
Second, these organisms absorb water. Normally, water rushes down between the sand grains just like beach sand. This slows water permeation, allowing larger plants to absorb more through their roots. The bumpy texture also allows water to pool for new seeds.
Third, cyanobacteria take nitrogen from the atmosphere and add it to the soil. Surrounding plants can use nitrogen as "food" to grow.
Fourth, fungi eat dead plants and animals, turning them into more food for living plants and animals. In arid regions, food is already scarce.
Don't take the soil for granted. Biological Soil Crust is fragile. It can take centuries to grow back. Watch where you step! Stay on trails! And don't bust the crust!
Photo Credit: NPS/Washuta
