A DESERT HIKER’S GUIDE TO CRYPTOBIOTIC SOIL: DON’T BUST THE CRUST!
Have you ever wandered through the desert and wondered what the strange-looking bumpy layer of dark crust was on top of the dirt? It’s a common question, and an important one to ask for any outdoor enthusiast. What you’re looking at is not only unique, but also extremely vital to the desert’s ecosystem. It goes by the name of cryptobiotic soil crust, also known as biological soil, cryptogamic, or microbiotic soil crust.
If you’re a desert hiker, backpacker, climber, or photographer – or you plan to visit Southern Utah, you’ll want to read this through to the end. Understanding this vital biological soil crust is essential for any outdoor enthusiast because it’s found all over the world in arid and semi-arid environments. As adventurers in the outdoors, it’s our responsibility to be aware of the environment we’re exploring and do our part in preserving the land beyond our visit. Down below, I’ll explain what cryptobiotic soil is, why it’s so important, how to identify it, and how to reduce your impact.
Here’s everything you need to know about cryptobiotic soil crust and why it’s so important to protect.
A quick reminder, when getting outdoors, please practice good trail etiquette and remember to Leave No Trace. This means packing out all of your garbage, being respectful to others on busy trails, and following the established rules.
What is Cryptobiotic Soil Crust?
First, let’s break down the name. Crypto means ‘hidden’ and biota means ‘life’, so this literally translates to ‘hidden life’. From the naked eye, it looks just like crusty black dirt but there’s so much more to it. Biological soil crust is a living soil that’s comprised mostly of cyanobacteria, as well as lichen, moss, fungi, and other bacteria.
Cyanobacteria, aka green-blue algae, are one of the oldest life forms known to man. It’s said that this is one of the first organisms to colonize Earth, and it’s one of the major contributors to cultivating fertile soil across the globe. This cyanobacteria originally turned the carbon-dioxide rich environment into healthy oxygen, which allowed for other lifeforms to survive.
Photo source: Jason Hollinger
Why is Biological Soil Crust So Important?
Cryptobiotic soil has been dubbed the ‘protector of the desert’. The slow-growing cyanobacteria move through wet soil to form a complex web of sticky fibers. This web is what fuses soil particles together, creating a thick, hard layer for new growth, which also helps to prevent erosion. And, this layer has maximum water absorption thanks to its sponge-like make up. This function helps to regulate water runoff and reduce evaporation. As time goes on, other organisms begin to grow in the soil, including lichen, moss, fungi, and other bacteria.
It’s also a defender against erosion. Because the sticky webs of soil retain water, plant life is able to root into the spongy crust which enables them to survive hot, dry conditions. It then converts nitrogen from the air into usable nitrogen to help plants grow.
Research shows that large sections of the western United States have damaged crustal layers due to the increasing recreational and commercial uses of these areas. As a result, this increase in human activity and disturbance to the crust could lead to significant damage due to wind and water erosion, as well as nutrient loss.
When damaged, the colony of organisms could take several hundred to 5,000+ years to recolonize and reform in arid places (you read that right.) Basically, it can be irreparably damaged just by the stomp of the foot.
Biological soil crust is the lifeline of the desert because it plays a vital role in soil stability, moisture, and nutrient cycles. Without it, nothing can grow and the plant and animal life that rely on this, would not survive. Also, humans would not be able to fare well in the desert without this intelligent soil crust.
Damage to Cryptobiotic Soil (Photo Source: Sierra Club)
How to Identify Microbiotic Soil Crust
It’s important to know how to identify this soil because it’s very susceptible to damage by unaware hikers, off-road vehicles, and animal tracks. And, the first step in damage prevention is awareness.
Young biological soil crust is a little harder to identify than a mature crust. It’s flat and brown, much like regular dirt. But mature crust is thick, bumpy, and dark brown or black. It’s often coated with lichen or moss, which is a sign of maturity. These mature crusts could be thousands of years old (and you definitely don’t want to be the one that damages something that old, do you?) The older, mature crust is known to play a large role in the cryptogamic plant diversity of these regions.
Here are some photos to use as a reference, so you know what to look for on your next desert adventure:
Younger Cryptobiotic Soil in Canyonlands National Park, Utah (Photo Source: www.o1c.net)
El Morro National Monument, New Mexico (Photo Source: NPS photo Dale Dombrowski)
Mature Cryptobiotic Soil in Canyonlands National Park, Utah (Photo Source: Bill Bowman (University of Colorado) and Scott Ferrenberg (UCGS Moab))
How to Protect Microbiotic Soil Crust
This is the most important piece of information in this post. Loss of the soil means loss of fertility in the entire area around it, which could have devastating effects on the region.
These soil crusts are very, very fragile, even more so during dry seasons. Even the smallest amounts of pressure (by foot, car, or animal) can expose the sublayers beneath the surface, leaving the crust susceptible to erosion and threatening the living organisms. So, you can imagine how much of an adverse impact our actions can have on the region that depends on this crust.
Human footprints and animal tracks can crush the biological soil underneath, and driving or parking a vehicle atop it leaves an even greater impact. While we don’t have control over which way wild animals go, we do have the power to choose which way we go and where our pets wander.
So, the best way to preserve microbiotic crust is pretty simple: don’t go near it! If there are signs posted in the area notifying you of its presence, keep an eye out on the trail and on the road. And, most importantly, stay on the designated trail and road. Going off-trail or off-road with your vehicle increases your chance of accidentally tramping on the soil crust.
In the event that you do encounter it along the way and you’re unable to turn around or avoid it, the best practice is to walk in a single-file line with your group and pets to minimize the chance of widespread damage from your group’s impact. Then, kindly spread the word to any other people you meet along the way that might not have this information.
With the right information and education, we’re able to make better choices as responsible outdoor adventurers. This way, we can do the best we can with the information we have to protect and preserve the places we get to visit.
Interpretive Sign in Arches National Park, Utah
Photo Source: Wikimedia Commons
I hope that with this information you feel comfortable to identify cryptobiotic soil and understand why it’s so important to give it space and don’t crush the crust! Have you encountered this soil crust before? If so, where? Let us know in the comments below.