• Double O Arch

    Arches

    National Park Utah

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Disturbed Lands

photo: Aerial view of road scars in Arches
Aerial view of road scars in Arches
NPS Photo by Neal Herbert
 
Though much of Arches remains undeveloped, its lands are not necessarily undisturbed. Much of the area is covered by biological soil crust, a living crust found throughout the world that plays an important role in the ecosystems in which it occurs.

Unfortunately, many human activities negatively affect the presence and health of biological soil crusts. Compressional stresses placed on them by footprints or machinery are extremely harmful, especially when the crusts are dry and brittle. Tracks in continuous strips, like those produced by vehicles or bicycles, create areas that are highly vulnerable to wind and water erosion. Rainfall carries away loose material, often creating channels along these tracks, especially on slopes.

Wind not only blows pieces of the pulverized crust away, thereby preventing reattachment to disturbed areas, but also disrupts the underlying loose soil, often covering nearby crusts. Since crustal organisms need light to photosynthesize, burial can mean death. When large sandy areas are impacted during dry periods, previously stable areas can become a series of shifting sand dunes in just a few years. Air pollutants, both from urban areas and coal-fired power plants, also adversely affect the physiology of these crusts

Impacted areas may never fully recover. Under the best circumstances, a thin veneer of cryptobiotic soil may return in five to seven years. Damage done to the sheath material, and the accompanying loss of soil nutrients, is repaired slowly during up to 50 years of cyanobacterial growth. Lichens and mosses may take even longer to recover.

Avoiding these fragile crusts is simple. Always drive or ride on designated roads. Respect road closures and search for places wide enough to pass other vehicles rather than driving over roadside vegetation. When hiking, always walk on marked trails, or on other durable surfaces such as rock or in sandy washes.

Did You Know?

Pinyon Pine

Pinyon trees do not produce pine nuts every year. These delicious nuts can only be harvested every three to seven years. This irregular schedule prevents animals from adapting to an abundance of pine nuts and guarantees that at least some nuts will become new trees instead of a quick meal.