Natural Features & Ecosystems

To many, the most outstanding natural features of Colorado National Monument are the park's geological formations. In each of the canyons, visitors can see the remarkable effects of millions of years of erosion on a landscape of sedimentary rock.

Two unusual natural features are common in Colorado National Monument and intrigue both scientists and visitors: biological soil crusts and potholes.

biological soil crust
Biological soil crust

Photos courtesy of USGS Canyonlands Research Station

A graphic showing a booted foot stepping on fragile biological soil. Don't bust the crust!

Graphic Courtesy of USGS Canyonlands Research Station

Have you noticed the bumpy, knobby, and sometimes dark soil along the trails? That’s biological soil crust! Just like a coral reef is formed over time by lots of small organisms living together, soil crust is formed the same way. Moss, lichen, green algae, cyanobacteria (sigh-AN-oh bacteria), and microfungi all work together to hold sand grains in place and create an environment where seeds can grow.

Biological soil crust is extremely slow growing; a single footprint can erase decades of growth. You can help protect biological soil crust by staying on established trails. Don’t bust the crust!

Photo of a circular water filled pothole, hollowed out in sandstone.
Insects breed in water filled solution pits.

NPS Photo: Lynn Mager

Potholes are naturally occurring basins in sandstone that collect rainwater and wind-blown sediment. These potholes harbor organisms that are able to survive long periods of dehydration, and also serve as a breeding ground for many high desert amphibians and insects. Both of these communities are very vulnerable to human impacts.

Last updated: January 2, 2024

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Fruita, CO 81521


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