Cheat Grass - An Ecosystem Transformer

by Deborah Kennard- Professor of Environmental Science - CMU

Photo taken by David Smith

Ever wonder what those pesky sharp seeds are that hitchhiked home with you embedded in your hiking socks? That’s probably cheatgrass. Also known as downy brome or scientifically as Bromus tectorum, it’s one of the most widespread non-native noxious weeds in North America. The most vigorous of the “early season invasives,” cheatgrass greens up early in the spring stealing soil water from native plants that emerge later — thus earning its reputation as a cheater. 

Cheatgrass, also known as downy brome or scientifically as Bromus tectorum, is one of the most widespread non-native noxious weeds in North America. Native to Eurasia, cheatgrass found its way to North America in the mid-1800s, mostly by accident, hitching rides in bags of wheat seed. Once in the West, its early spread was aided by soil disturbance caused by livestock overgrazing. Biological soil crust, the web of fungi, moss, and other tiny organisms that protect desert soils, acts as a natural weed barrier for cheatgrass. Livestock hooves (or tires, boots, and fire) can disturb these soil crusts, opening areas to invasion. 

The arid West lacks native annual grasses that might otherwise colonize disturbed soil, so cheatgrass easily filled that vacant niche. Its weedy nature gives it a competitive advantage over native plants, as it can establish itself and spread before other species have a chance to recover. 

Not only does cheatgrass spread like wildfire, it is notoriously effective at spreading wildfire. Wildfires use plants as fuel, and how a fire behaves is, in part, controlled by the amount, size, shape and moisture content of plants. Cheatgrass is changing all these traits of wildland fuels. Cheatgrass invades arid landscapes that typically have very patchy plants, a natural fuel pattern that prevents fires from spreading. By filling these empty spaces, cheatgrass covers the landscape with a connected fuel bed of thin, dry “flashy” fuels — perfect for promoting the spread of fire. Cheatgrass has also shifted the seasonal timing of wildfires. Because this grass greens-up earlier in the spring than native plants, it also dies, dries, and becomes flammable before native plants.

After the flames are out, cheatgrass kicks into overdrive. 

A single cheatgrass plant, fertilized by nutrients released by a fire, can produce a whopping 5,000 seeds. These seeds can produce a dense monoculture of over 1,000 plants per square foot, hindering perennial native plants that may be slower to recover after fire. Called the “grass-fire cycle,” these flammable post-fire grasslands increase the likelihood of future fires, reinforcing cheatgrass’s dominance. These vicious feedbacks can trigger what ecologists call a “type conversion,” where vegetation shifts to a completely different type, for example, from a sage shrubland to a grassland. In fact, this grass-fire cycle has had the most dramatic effects on sagebrush ecosystems, creating more “megafires” (fires that exceed 100,000 acres) in these shrublands than the headline-grabbing forest fires.

Breaking the grass-fire cycle is a significant challenge. After the type-conversion threshold is crossed, only intensive human intervention can restore native plants and the natural fire cycle. So far, there is no single silver bullet. Some biocontrol agents, like a fungus that kills cheatgrass seed ominously named the “black fingers of death” generated some excitement, but scientists eventually found it only worked under limited conditions. Decades of field trials show that a combination of limiting disturbances, helping native species get a foothold by reseeding, and more careful rotation of livestock can control the spread of cheatgrass. While chemical control can be controversial and is expensive, there are herbicides designed to prevent seed germination of only early season annual grasses, like cheatgrass, giving native plants several crucial growing seasons to colonize. 

Fortunately, the Colorado National Monument has a low abundance of cheatgrass compared to other parts of Mesa County. Part of this good fortune is due to the low level of soil disturbance provided by the park’s century of protection. The park is also diligent in removing non-native invasive species. Summer crews of young adults, often working with the Western Colorado Conservation Corps, spend many hours removing noxious weeds. But also, the park’s ancient pinyon-juniper woodlands provide a natural resistance to cheatgrass invasion. As pinyon pine and juniper trees grow older, more ground becomes shaded by their expanding crowns. This increase in shade causes a decline in understory sun-loving plants, including cheatgrass. 

Although large fires are exceedingly rare in the park’s unique landscape, this relatively sparse understory can make these ancient woodlands vulnerable to cheatgrass if a fire were to occur. An abundance of native grasses and wildflowers can keep cheatgrass at bay. But if seeds of native grasses and wildflowers are depleted in soils below tree crowns, even a few surviving seeds of cheatgrass could invade and dominate early stages after a fire. So, the hard work of park managers to control cheatgrass not only benefits the present ecosystem but also pays dividends well into the future.  

Desert Bighorn Sheep Part II

by Camille Jestrovich

CNMA Bookstore Sales Associate

photo taken by Paul W. Meyer

Desert bighorn sheep are some of the most captivating mammals in canyon country. Here are some fascinating and fun facts about these iconic animals that have such meaningful environmental, social, and recreational benefit.

Bighorn sheep are communal animals that live in groups for most of the year.

Ewe groups, or bands (made up of adult and young ewes, young rams, and lambs) are larger than the ram bands. These nursery bands are generally largest in the late spring and early summer. Mature rams usually remain solitary or in bachelor flocks until August when pre-rut begins. At this time, the bachelor herds break up and rams search for ewes.

Rut, an intense competition to establish access to the ewes, lasts from around September through November. The age and size of the horns usually dictate which rams will dominate. The competition for females begins with two males sizing each other up, rearing up on their back legs and charging towards each other at a speed of about forty miles an hour, with a crash that can be heard miles away. This battle to prove their dominance has been observed to go on, in some cases, longer than twenty-four hours, and the competition itself can last for a month. In the end, only one ram is chosen to mate with the ewes. Moreover, this situation could easily change with the next challenge.

Ram courtship starts with a series of actions such as twisting, kicking, and chest pushes. Ewes generally reproduce in the third year. Gestation lasts six months, and usually only one lamb is born to a ewe in the early spring. The lambs are precocial and capable of walking and climbing on their first day of life. Desert bighorns employ a nursery system. Several ewes will wait with all the lambs out of harm in escape terrain. The mothers in the band will proceed to areas where they can feed on delicious spring vegetation. Lambs are well-mannered with those left in charge while their moms are away. The grazing ewes return to nurse the lambs, trading places with the nursery group. The lambs stay out of sight for about a week and then they begin to follow their mothers. They are entirely weaned by four to six months of age. Unfortunately, due to the harsh conditions and predators, few lambs survive until October. Young ewes frequently remain in their mother’s band while males depart the group at around age two to four years of age when they join a bachelor group.

There are four fundamental necessities of desert bighorn sheep: escape terrain, food, water, and space.

One of the critical features in the bighorn sheep habitat is the rugged landscape. Bighorns use escape terrain to evade predators which consist of coyotes, bobcats, bears, cougars, and eagles that pray on lambs. Instead of running long distances, they avoid their enemies by ascending cliffs and hiding in this rocky terrain. Rock outcroppings, talus slopes, and cliffs furnish habitat for lambing, resting, and escape cover. It is common for rams to move farther away from protection than the females.

Bighorn sheep are adept at climbing. They owe this ability to having specialized cloven hoofs. The outer hooves are sharp-edged modified toenails formed to catch the smallest projection and the inner pad is soft and spongy. The result is a padded, rubbery sole that aids them in keeping their balance and traction as they maneuver up sheer rock faces. Because of their incredible balance, they are able to stand on ledges barely two inches wide, jump 20 feet, and run up a cliff at fifteen miles an hour.

Bighorn sheep eat a wide array of plants depending on the season. Their diet is largely dominated by forbs, followed by grasses (in particular, Indian rice grass), and lastly browse, especially Blackbush and Mormon Tea. During the summer months, when the green, potassium rich forage has been consumed, the sheep also seek out sodium mineral licks. While ewes seem to utilize areas that minimize the possibility of predation to offspring, rams may take advantage of areas offering better nutrition. Rams are apt to eat, rest, and ruminate which makes digestion more efficient and leads to an increased body size. Ewes tend to walk as they forage, likely, in order to evade predators and safeguard their young.

Bighorn sheep have an intricate nine-stage digestive process that allows them to readily remove nutrients from their food. As a ruminant, they have a four-part stomach. After grazing on large quantities, bighorns chew their cud, before digesting it again. Through this digestive process they are also able to absorb moisture, allowing them to go long stretches without water.

The primary limiting factor for desert bighorn sheep is water. They will search out surface water in springs, seeps, potholes, and seasonal streams. They also feed on the water storing flesh of the prickly pear cactus, which they break open with their horns. In summer, rams can go several days without drinking, getting the water they need from plants. Ewes, especially when lactating, need a regular supply of water. Fortunately, in this area, at this time, the sheep have access to either springs or the Colorado river to drink from.

Desert bighorns favor open space around their water supply so they can detect predators but they won’t roam more than a few meters from escape terrain. The groups also protect themselves by standing or lying facing different directions, permitting them to watch over their environment and spot danger from all sides.

Both rams and ewes use their horns for eating and fighting.

The female’s horns are short with a slight arch. They will joust head-to-head or head-to-ribcage with other ewes in order to establish dominance with other females in the group. The ram has massive curved horns which can weigh up to thirty pounds. Rams can regularly be seen rubbing their horns on rocks, trees, and shrubs for various reasons. Butting trees can be good practice for younger rams. Because their horns grow continuously, they are compelled to grind their horns against rocks to file them down or break off the tips, making them blunt. This action is called “brooming.” If they didn’t engage in this behavior, in the course of time, the horns would curl in front of their eyes hindering their vision.

The horns are a two-part structure. An internal portion of bone (a continuation of the skull) is shielded by an exterior covering of hair follicles very much like human fingernails. The thick bone has specialized honeycombed chambers with bone struts and broad tendons that connect the skull to the spine. They are built to withstand skull to skull combat which can exert eight hundred pounds of force. According to wildlife biologist Kevin Brennan, in very intense summer heat, the honeycombed chambers also aid in keeping the brain cool. Bighorns also have an exceptional cooling system which involves both panting and sweating. This is most rare in that nearly all animals do one or the other.

Desert bighorn sheep have adapted to the extremes in their environment in many ways.

Desert bighorn sheep’s kidneys are remarkably effective allowing an astonishing moisture loss of as much as 30% of the bodyweight. Compare that to a camel that can lose 25% of its body weight during severe dehydrating conditions without a threat to their health. Like a camel, they can drink huge quantities of water at a time when they locate it and fully recover.

Over the millennia, desert bighorn’s have also adapted to their desert surroundings by donning an efficient coat comprised of coarse, hollow hair. They can tolerate heat unlike any other ungulate besides the camel. In severe heat, instead of absorbing heat, they radiate it. Conversely, in winter, their specialized coat helps them stay warm and acts as insulation from the elements.

Sheep depend greatly on their vision.

Bighorns have wide-set eyes that are placed forward on the head, allowing for superior peripheral vision. It is possible for the bighorn to see behind them without turning their heads. They are unable to see well directly in front of their noses, however, and have poor depth perception. Excellent peripheral vision, along with a great sense of smell help detect dangers in their surroundings.

Keep your eyes peeled for these hardy desert-dwellers on your next trip over the Monument!

Thank you to Genevieve Fuller, Wildlife Biologist at Colorado Parks and Wildlife for graciously answering my many questions!

Other information gathered from the following sources:

naturemappingfoundation.org Bighorn Sheep Facts

https//:cpw.state.co.us Herd Management Plan

https//: www. nps.gov Desert Bighorn Sheep

mitton@colorado.edu – professor Department of Ecology and Evolutionary Biology at University of Colorado – column in Boulder Camera

YouTube lecture series Genevieve Fuller Wildlife Biologist

Desert Bighorn Sheep – Wilderness Icon by Mark C. Jorgensen

The Desert Bighorn: Its Life History, Ecology, and Management Book by Gale Monson and Rex W. Allen

Grandmother Tree

Written by Lisa Lesperance Kautsky, LPC

Red Bike Counseling

It’s a fine fall day, and the Blue of the Colorado Sky dominates. A welcoming granite boulder lends a seat and I take it, lean back, and stare into the endlessness of Blue. I inhale Blue and imagine it swirling around inside. Soon, I feel an expansiveness in my heart and my heart unlocks – heart now softened and malleable. The present moment descends from on high and feels visceral – like I could grab a handful of it and take it back home with me.

My eyes drift from Blue to mottled sandstone cliffs towering above. Where the sun hits just right, portions of the cliffs carry a sheen. Below the mottling and sheen is a community of pinyons and junipers. The green feels good on the eyes. I gaze at green and see baby saplings, adolescents, mature trees, and relics of the past.

But my eyes are drawn to an ancient, gnarled pinyon. I study this tree. The trunk winds and bends and comes back up again. Some roots are exposed. Some branches look lifeless, and one branch is completely broken off. Some branches host needles and pinecones, while others do not.

This is Grandmother Tree.

I study Grandmother Tree…Her roots have carved through layers of earth to find sustenance for life. I wonder,

How old is Grandmother Tree?

She has seen much, and I imagine her knowledge and wisdom run deep, as deep as her roots.

I want her knowledge and wisdom.

I mimic her.

Soon, I sense my limbs as branches, my hair as needles, my veins as sap, and find myself growing roots, deep through layers of earth…

just like Grandmother Tree.

How did you survive this desert living? I ask her.

She recounts tales of strong winds, deep freezes, years of drought, scorching sun, sheets of hail. What an ordeal, I think to myself, and sense her pain, my own pain, the pain of the world.

I empathize with Grandmother Tree – Yes, desert living is hard. Life is hard, I tell her. Grandmother Tree pauses long and thoughtfully before she responds. Finally, Grandmother Tree amends my thoughts with this:

It is about the stories we tell ourselves. When you see yourself as a victim, you remain a victim, and you remain powerless. But when you see yourself as a survivor, you become empowered.

www.redbikecounseling.com 

Walks and Talks

Thank you to all who attended one of our many events this spring, we enjoyed trying out a few new classes and bringing back some of our favorites.

Thank you to all of our instructors who graciously volunteer their time for this program.

We look forward to fall planning and hope that you will join us again. Our new website has a calendar on it that will include CNMA events for you to check out and sign up when registration is required. Be sure to subscribe to the calendar, as well, to keep you updated when new events are added!

Thank you,

Karen Mahoney

Program Coordinator

Colorado National Monument Park Passes

Do you feel like you would benefit from an annual pass to Colorado National Monument? 

If you haven't been able to visit our beautiful local National Park often or at all due to entrance fees, we want to help!

Colorado National Monument Association (CNMA) wants to help provide access for all into Colorado National Monument and will give free annual passes to those who want to visit and enjoy these lovely red rock canyons.

If you are interested, please email johannavwaveren@coloradonma.org or give us a call at (970)858-3617 ext.307.