Tread cautiously in Colorado’s fragile, living desert
April 8, 2015
For many desert goers, "tiptoe through the crypto" is a familiar mantra, but as the weather warms and spring beckons downvalley, some locals may be headed for the canyon country for the first time, unaware of the damage they could unwittingly inflict on the fragile desert ecosystem.
Officials at the Bureau of Land Management's Colorado River Valley Field Office have some recommendations on how to enjoy the desert while leaving it intact for others.
Perhaps the most important thing newcomers fail to understand is that the ground is alive. Biological soil crusts, composed of some of the earliest forms of life — cyanobacteria, algae, fungi, and lichens — make up a common and essential part of the desert ecosystem.
"The slick-rock canyon country of western Colorado and southeastern Utah has some beautifully developed biological soil crusts that typically create a knobby black ground cover between the pinyon and juniper trees, and the blackbrush, saltbush and sagebrush shrubs," explained Botanist Judy Perkins. "Biological soil crusts are extremely effective at stabilizing soil and preventing both wind and water erosion. However, they are quite fragile in the face of human activities."
“Particularly in dry conditions, the filaments of cyanobacteria are easily broken by foot traffic, livestock hooves, mountain bike tires, ATVs and other motorized vehicles. Walking, biking, or driving across the crusts can cause damage to the crusts that may take decades to heal.”Judy PerkinsBLM botanist
Also known as cryptobiotic earth, the crusts benefit plants in various ways, like fixing nitrogen and aiding photosynthesis, but in the desert their most important role is stabilizing the soil and aiding water retention.
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"Larger species of cyanobacteria, such as those in the genus Microcoleus, produce long filaments surrounded by a slimy sheath which grow around individual sand grains and soil particles, literally gluing the soil in place," Perkins said. "While only the surface cyanobacteria growth is alive, older dead filaments continue to cement the soil in place, often creating a thick layer of stabilized soil. The surface knobs of well-developed crusts capture water from rains, and influence water infiltration into soils."
While the crust can sometimes grow back after being damaged, it's a slow process.
"Particularly in dry conditions, the filaments of cyanobacteria are easily broken by foot traffic, livestock hooves, mountain bike tires, ATVs and other motorized vehicles," Perkins said. "Walking, biking, or driving across the crusts can cause damage to the crusts that may take decades to heal."
STAY ON THE PATH
That's part of the reasons one of seven principals put together by the nonprofit Leave No Trace Center for Outdoor Ethics is "travel and camp on durable surfaces,"
Many desert trails have signs urging visitors to stay on the path. If you have to cross a patch of crust for some reason, most authorities suggest walking in single file to minimize impacts. Try to avoid making a new trail which might send others off the main path.
Disturbance of soil crusts and other ground disturbances, such as roads and trails, also create ideal locations for noxious weeds and other invasive plants to establish, and recreationists should avoid spreading weeds while they are enjoying the canyon country.
"Many weed species have specially adapted seeds that piggy-back on hikers' bootlaces, socks and pants, and are unwittingly spread into previously weed-free locations."
Perkins suggests checking your clothes and pets for seeds before moving to another area, and strongly encourages washing your car — including the undercarriage — before heading somewhere pristine.
Besides the local impacts, soil disruption has some large scale implications.
"Research has correlated large-scale disturbance of soil crusts in southeastern Utah to increased sedimentation in the Colorado River drainage, as well as reductions in soil nutrient levels," Perkins said. "Impacts to biological soil crusts in western Colorado and southeastern Utah also have the potential to impact us here in Colorado. With loss of soil stability, windblown dust deposition in the Colorado Rocky Mountains has increased."
Dusty snow melts faster, meaning a faster runoff and a drier summer in the mountains.
Another important Leave No Trace principle is "respect wildlife," which Allen Crockett, BLM natural resource specialist and author of "The Ecology of Colorado: Landscapes, Plants, and Wildlife of the Centennial State" can't emphasize enough.
When it comes to the desert, he's particularly worried about amphibians.
"While small streams and scattered pools, such as in canyons, represent a tiny percentage of the desert landscape, they receive sometimes heavy recreational use," Crockett said. "Unfortunately, these areas represent essentially all of the suitable breeding locations for the canyon treefrog, which barely enters western Colorado, and many occurrences of the red-spotted spotted toad."
According to Crockett, desert amphibians generally become active in late spring and early summer, when rains provide enough water for the adults to gather and breed, for eggs to produce water-breathing tadpoles, and for these to grow and metamorphose into air-breathing toadlets. For about two months, the already-tenuous reproductive cycle is particularly vulnerable. An unwitting hiker or unleashed dog walking through or playing in a stream could have tremendous impacts.
Crockett suggests checking streams and pools for eggs, tadpoles or adult amphibians before entering. If you can't avoid wading, try to avoid clusters of tadpoles and minimize splashing and stirring up sediment.
"In general, desert etiquette relative to wildlife is the same as anywhere, with a focus on observing wildlife from a respectful distance that clearly does not alter their behavior," Crockett explained. "Being displaced is potentially more impactful in harsh environments, where suitable sites for certain behaviors may be few and far between."
The remaining Leave No Trace principals are also simplified in the desert.
"Dispose of waste properly" gains an extra meaning when, away from designated facilities, visitors are required to pack out human waste due to the scarcity of soil. Archaeological sites make "leave what you find" paramount, and "minimize campfire impacts" is paramount in arid climates. "Plan ahead and prepare" and "be considerate of other visitors" focus more about people than the environment, but help assure everyone's safety and enjoyment.
For more information on Leave No Trace, visit lnt.org/learn/7-principles.