You Need This Crust

rjzimmerman:

Whenever I’m “off trail” in the desert, whether doing volunteer work, or going off trail on a hike to snag that mylar balloon remnant dangling in the botany, or walking over that-a-way to that boulder to get a better photograph, I look down for two reasons. One, avoiding stepping on cryptogamic soil, and, two, to avoid rattlesnakes. I think I’m more fearful of getting yelled at by a desert conservationist about the soil than I am about rattlesnakes.

Excerpt from this story from Sierra Club:

I hadn’t walked very far along the trail in Arches National Park before I started to see the signs. Planted alongside the asphalt of the trail were little posts that read “Your steps matter. Protect park soils.”

Many visitors hadn’t gotten the message. Boot and sneaker prints extended past the boundary, out into the pale red soil. Perhaps the people who had left them didn’t understand that the pleas weren’t just the national park equivalent of “Keep off grass.” When hikers tread off the path, they are trampling on empires—incredible, communal organisms that are vital to the health of the desert.

Microbiotic soils (also known as biocrust or cryptogamic soil, depending on who you’re talking to) are found in arid places around the world. The term might seem a bit strange, given that all soil contains a panoply of microscopic organisms  But what distinguishes microbiotic communities is that they are a collaboration of different entities—fungi, lichen, cyanobacteria, algae, and other tiny organisms that come together in just the top few millimeters of soil.

Despite their unassuming appearance, these dark crusts on the surface of arid soil are actually tiny towers that are critical to the health of the desert. Biocrusts take in carbon and nitrogen and place it back into the soil, where it can be used by surrounding plants. They help keep the desert together—not only preventing dry sediment from blowing away on the wind but trapping sand and dust that’s blown over them. Biocrusts often retain heat too, helping to regulate the rhythm of who’s active when in these arid places. Some organisms found in biocrusts even produce compounds that help to break down pesticides and herbicides, meaning that crusts can help detox the desert such that biodiversity can return to places suffocated by human activity.