Wild About Utah

April 25, 2013June 27, 2016

Cryptobiotic Soil Crusts

Click to view larger image of Cryptobiotic Soil Crust, Photo Courtesy and Copyright Mark Larese-Casanova — Cryptobiotic Soil Crust
Photo Courtesy & Copyright 2009
Mark Larese-Casanova

Hi, this is Mark Larese-Casanova from the Utah Master Naturalist Program at Utah State University Extension.

Looking out over a Utah desert, we might see relatively few plants- perhaps some sagebrush, maybe a few junipers or Joshua trees, or even some small wildflowers or cacti. What is less noticeable, though, is the living soil crust that holds this entire landscape together. It’s not just sand, but rather an important and vast partnership between bacteria, lichens, algae, and fungi. These soil crusts are often referred to as ‘cryptobiotic’, which means ‘living in suspended animation’. This is a fitting description, considering that water can be so rare in Utah’s deserts.

Cyanobacteria, which is often called blue-green algae, is the backbone of cryptobiotic soil crust. Vast networks of long, microscopic filaments of cyanobacteria and fungi grow in length when they are wet, and leave behind a casing that literally binds the soil together. So, what might otherwise be loose sand not only is less likely to be washed away by water or blown away by wind, but also is able to hold much more water for plants.

Cyanobacteria is also extremely useful to desert landscapes for its ability to take Nitrogen out of the air and make it available to plant roots in the soil. Desert soils typically have relatively low nutrients, so this is especially important to desert plants.

In many Utah deserts, cryptobiotic soil crusts can cover up to 70% of the ground surface. Old soil crust can often look like small mountain ranges with black or white peaks inhabited by lichens or mosses. The little valleys in between the tiny mountains of crust are perfect spots for the seeds of desert plants to grow. Over time, the above ground crust can grow up to ten centimeters, or four inches, thick!

However, cryptobiotic soil crust grows at an alarmingly slow rate of about one millimeter per year. So, any soil crust that is disturbed can take a very long time to recover. Depending on the amount of moisture a desert receives, it can take anywhere between 20 and 250 years for soil crust to grow back.

Next time you’re out in the desert, kneel down and have a close look at the telltale peaks and valleys of cryptobiotic soil crust. If you bring a magnifying glass, you just might be able to see some of the lichens and mosses. Be sure to stay on trail, though, and whatever you do, don’t bust that crust!

For Wild About Utah, I’m Mark Larese-Casanova.

Credits:

Images: Courtesy and copyright Mark Larese-Casanova
Text: Mark Larese-Casanova, Utah Master Naturalist Program at Utah State University Extension.
Additional Reading:

US Department of Interior. 2001. Biological Soil Crusts: Ecology and Management. Bureau of Land Management Technical Reference 1730-2., https://www.blm.gov/nstc/library/pdf/CrustManual.pdf
Rosentreter, R., M. Bowker, and J. Belnap. 2007. A Field Guide to Biological Soil Crusts of Western U.S. Drylands. U.S. Government Printing Office, Denver, Colorado., https://www.soilcrust.org/

April 18, 2013July 23, 2025

May Swenson: Observer of nature and Utah poet

Hi, I’m Holly Strand from Stokes Nature Center in beautiful Logan Canyon.

In Logan Cemetery a granite bench marks the grave of May Swenson, a native Utahn and eminent poet. She was born in Logan in 1913 and attended Utah State University where she published her first poem. She moved east in 1936, and eventually, she became one of America’s most inventive and recognized poets, She won many awards including Guggenheim and Rockefeller grants, the Yale Bollingen Prize, and the MacArthur Foundation Fellowship. Utah State University conferred an honorary doctorate on Swenson in 1987. Despite her many achievements and her years living away from Utah, Swenson never forgot her Mormon heritage or her identity as a Westerner.

Nature played a prominent role in Swenson’s work. In fact, she published a collection of poetry called Nature: Poems Old and New which is brimming with imagery that evokes the beauty and complexity of the natural world.

Here’s an example: a poem called April Light read by Paul Crumbley, a professor of English at Utah State University who specializes in Swenson’s work.

April light
Lined with light
the twigs are stubby arrows.
A gilded trunk writhes
Upward from the roots,
from the pit of the black tentacles.
In the book of spring
a bare-limbed torso
is the first illustration.
Light teaches the tree
to beget leaves,
to embroider itself all over
with green reality,
until summer becomes
its steady portrait
and birds bring their lifetime
to the boughs.
Then even the corpse
light copies from below
may shimmer, dreaming it feels
the cheeks of blossom.

Another of Swenson’s poems describes a well-known natural feature in Utah.

Listen to this excerpt of Above Bear Lake:

A breeze, and the filtered light makes shine
A million bristling quills of spruce and fir
Downslope, where slashes of sky and lake
Hang blue—windows of intense stain. We take
The rim trail, crushing bloom of sage,
Sniffing resinous wind, our boots in the wild,
Small, everycolored Rocky Mountain flowers.
Suddenly, a steep drop-off: below we see the whole,
the whale of it—deep, enormous blue—
that widens, while the sky slants back to pale
behind a watercolored mountain.

Listening to this makes me feel like I’m standing on the scenic outlook at the summit of Logan Canyon. That is, of course, where Swenson wrote it.

For more on the Utah poet May Swenson, see our website www.wildaboututah.org
Thanks to Paul Crumbley and Maria Melendez of the English Dept. at Utah State University.
And thanks to the Rocky Mountain Power Foundation for supporting the research and development for today’s program.

For Wild About Utah and Stokes Nature Center, I’m Holly Strand.

Credits:

Readings: Paul Crumbley and Maria Melendez of the English Dept, Utah State University

Text& Voice: Holly Strand, Stokes Nature Center

Learn More:

Holly’s pieces on Wild About Utah

Knudson, R.R. and Suzzanne Bigelow. 1996. May Swenson: A Poet’s Life in Photos. Logan, UT: Utah State University Press, https://www.jstor.org/stable/43021931

Swenson, May, Nature: Poems Old and New, Mariner Books (fmr: Houghton Mifflin Harcourt), April 19, 2000, https://www.amazon.com/Nature-Poems-Old-May-Swenson/dp/0618064087

The life of Utah poet May Swenson, with Margaret Brucia, Access Utah with Tom Williams, https://www.upr.org/show/access-utah/2025-07-14/the-life-of-utah-poet-may-swenson-on-access-utah

April 11, 2013January 24, 2021

Fossil Formation

Click for a larger view of a fossil, Courtesy and copyright 2008 Stokes Nature Center, logannature.org — Fossilized fish
*Mioplosus labracoides*
Copyright 2013 Stokes Nature Center
Andrea Liberatore, Photographer

Fossilized fish
Copyright 2013 Stokes Nature Center
Andrea Liberatore, Photographer

Horn Corals from Logan Canyon
Copyright 2013 Stokes Nature Center
Andrea Liberatore, Photographer

Fossilized leaf
Copyright 2013 Stokes Nature Center
Andrea Liberatore, Photographer

Fossilized shells
Copyright 2013 Stokes Nature Center
Andrea Liberatore, Photographer

The most popular school program that the Stokes Nature Center offers is a geology lesson for second grade. I’m not sure what happens between second grade and adulthood to make our general perception of geology go from exciting to boring, but you would be amazed at how excited second graders get over rocks, and especially, over fossils.

Fossils are really quite rare – a very specific set of conditions have to be met in order to create one. Most living things decompose fairly rapidly upon death, leaving no trace of their existence behind. In order to create a fossil, this process of decomposition needs to be halted fairly rapidly, which typically means that the body is quickly covered by some kind of sediment – like sand, or soil or mud. For this reason, most fossils are found embedded in sedimentary rock. If pressure and moisture levels are just right, over the course of millions of years the organism’s molecules will slowly be replaced by minerals from the surrounding sediments – eventually turning bone into stone.

Only somewhere around one in a billion bones will make it through this process. From there the fossil has to remain intact and identifiable through eons of tectonic plate movement, earthquakes, and mountain uplift. Then, in order to be found it has to be located near enough to the earth’s surface, and in such a place where a human might come across it. Some geologists estimate that only 1 in 10,000 species that have ever lived have made it into the known fossil record, which makes me wonder what discoveries still await us.

Fortunately for us, prehistoric Utah was a place where fossilization happened with some regularity, as evidenced by places like Dinosaur National Monument and the Escalante Petrified Forest. Did you know that Utah has a state fossil? That distinction goes to the allosaurus, a predatory dinosaur that thrived during the Late Jurassic period. Numerous skeletons found in east-central Utah range in size from 10 – 40 feet in length, meaning this fearsome creature may have rivaled it’s more famous cousin Tyrannosaurus Rex for top predator status.

With such a rich fossil history, it’s not out of the question that you might stumble onto something truly amazing during a routine hike. Can you keep your find? Well, that depends on two things: the type of fossil, and whose land it was found on. On public lands in Utah, fossils of vertebrates cannot be collected, while fossils of invertebrates and plants can be. Private land owners have full rights to the fossils found on their property. With all fossils, it’s a great idea to report your find to the US Geological Survey so that your discovery can be documented for public or scientific research, display or education.

Fossil creation is an incredible phenomenon that has allowed us to glimpse the earth’s history in ways that would otherwise be completely hidden. Thanks to fossils, we can envision a prehistoric landscape filled with giant ferns, enormous dragonflies, long-necked allosauruses, and flying pterodactyls. Without the evidence in the fossil record, I doubt that even the most imaginative person among us could have envisioned such an amazing array of life.

For the Stokes Nature Center and Wild About Utah, this is Andrea Liberatore.

Credits:

Photos: Courtesy & © Stokes Nature Center, logannature.org
Text: Andrea Liberatore, Stokes Nature Center, logannature.org

Additional Reading:

State of Utah, Utah Geological Survey, Dinosaurs & Fossils (2011) https://geology.utah.gov/utahgeo/dinofossil/index.htm

McCalla, Carole and Eldredge, Sandy (2009) What should you do if you find a fossil? Utah Geological Survey. Accessible online at: https://geology.utah.gov/surveynotes/gladasked
/gladfossil_collecting.htm

Trefil, James (1996) 101 Things You Don’t Know About Science and Nobody Else Does Either. Houghton Mifflin Company: New York, NY, https://www.amazon.com/Things-Dont-About-Science-Either/dp/0395877407

Bryson, Bill (2003) A Short History of Nearly Everything. Broadway Books. New York, NY, https://www.amazon.com/Short-History-Nearly-Everything-Illustrated/dp/0307885151

April 4, 2013March 4, 2026

Why Some Birds Flock in the Vee Formation

Spring is that magical season when avian migrants return north from more balmy climates. Utah’s migrants range from ponderous pelicans to tiny hummingbirds, honking geese to crying curlews. Many arrive as they departed, in flocks.Why Some Birds Flock in the Vee Formation

Kevin Colver: Songbirds of Yellowstone, Canada Goose)

But why fly in a flock at all? One reason is predator evasion, the same reason that minnows school and elk, bison and deer bunch in herds. Embedded in a swirling mass of birds called a swarm flock, an individual bird is less likely to be picked off by an aerial predator, such as a falcon or a Cooper’s Hawk. A raptor diving into a swarm flock risks collision and injury. Targeting a bird in a swirling group is visually difficult too. Flying in a flock gains safety, but at what cost? Pigeons flying in a swarm flock take shallower, more frequent wing strokes than a solo bird. Faster wing beats probably provide more control to better negotiate turbulent aerial traffic, but extra flapping costs more in energy.

In contrast, pelicans and other big birds often fly in tidy formation flocks. Flying in a vee formation, a trailing pelican’s heart beats 13% slower than the lead bird. That’s because a trailing pelican flaps less than the leader. Unlike pigeons, then, a pelican flying in a formation flock uses less energy, not more. Big birds with slow wing beats share aerodynamic attributes with airplanes. Some of the air under their wings swirls out from under the tips, creating a spiraling vortex that trails the wing tip. Flying in a tight vee formation, each trailing bird gets a bit of lift from the upwash created by that vortex, and so it can flap a little less and glide a little more. Lead birds tire more quickly, so leaders change periodically. Leaders lose their zip, not their way. In a vee, birds also have their flock mates in good view, which is needed for the tight precision of a formation flock.

(Kevin Colver: Songbirds of Yellowstone, Sandhill Crane)

Pelicans, swans, geese, cranes, ibis, ducks, godwits, they all ply the Utah sky in formation flocks. They may be bird-brained, but our bigger migrants know a thing or two about aerodynamics.

Credits:
Images: Courtesy & Copyright Brenda Bott, Photographer
Text: Jim Cane, Bridgerland Audubon Society https://www.bridgerlandaudubon.org

Video:

Spectacular flock (called a “murmuration”) of starlings, Sophie Windsor Clive & Liberty Smith, https://www.youtube.com/watch?v=iRNqhi2ka9k As viewed from Islandsandrivers.com. Contains advertisements.

Van Ijken, Jan, Flight of the Starlings, National Geographic, Nov 15, 2016, https://youtu.be/V4f_1_r80RY
See also https://www.janvanijken.com/film-projects/the-art-of-flying/theartofflyingfullversion/

Additional Reading:

Avian flight by John J. Videler. 2005. New York, Oxford University Press. 258 pp.
Contents:

Acquisition of knowledge
The flight apparatus
Feathers for flight
Aerodynamics
Evolution of bird flight
Bird flight modes
The bird flight engine
Energy required for flight
Comparing the metabolic costs of flight

Usherwood JR, Stavrou M, Lowe JC, Roskilly K, Wilson AM. 2011. Flying in a flock comes at a cost in pigeons. Nature. 2011 Jun 22;474(7352):494-7. https://www.researchgate.net/publication/51242928_Flying_in_a_flock_comes_at_a_cost_in_pigeons

Weimerskirch H; Martin J; Clerquin Y; Alexandre P; Jiraskova S. 2001. Energy saving in flight formation. Nature. 413: 697-698. https://eol.org/data_objects/16885552