out on the range

Cheatgrass is choking out native flora

in Zion National Park.

(Photos by Steven H. Rich)

Zion National Park is ãcheatgrass central.ä Itâs cheatgrass heaven. Little cheatgrass seeds all want to grow up in Zion, and billions do. It grows on north-, south-, east-, and west-facing slopes. It lives under every kind of shrub and tree in the park; on open flats; in riparian areas (streamside zones); in cryptogamic (cyanobacterial, moss or lichen) soils; and grows out from under rocks.

Cheatgrass is everywhere in Zion. The seeds fill peopleâs socks. If they lie down, clothes get stuck full of pointy nonnative cheatgrass seeds hitching a ride to start another invasion. Itâs cheatgrass hog heaven where cheatgrass hogs all the (herbaceous, grass and flower) opportunities.

A 500-point study conducted by this author in Zion National Park in 2004 found no ãhitsä on native grasses or forbs at all. It was 500 for 500÷all cheatgrass. To be sure, there are native grasses and forbs in the park, but they are a tiny minority, outnumbered hundreds- or thousands-to-one in all but the highest altitudes where a wetter climate favors perennials over desert and steppe dwellers like cheatgrass.

According to the range science professionâs ãStandards for Evaluating Indicators of Rangeland Health,ä this amounts to an extreme variance from the potential natural [herbaceous] community. The native shrubs and trees are there. The native grasses and flowers are really hurting.

Letâs be clear on this: long-term livestock removal did not create ãrestoration.ä In Zion, it created ãnaturalishnessä (a rhetorical state of pretended naturalness) and, well, lots of cheatgrass. Several structural groups (not single species, entire groups of species) of plants are missing or represent approximately one percent of the herbaceous community in most of Zion, the herbaceous community of which is about 99 percent cheatgrass (when grouped with red brome and ãrip-gutä brome÷two mean, aggressive cheatgrass relatives). So much for natural arrays of native organisms!

All competent range scientists know this. They also know that vast landscapes and many decades of real-world experience hugely trump narrow-point rhetoric based on microphenomena in study plots the size of a living room, or snapshot studies on sites that vary widely over time.

The Paria Plateau southeast of Zion, as an example in contrast, shares soil types, ecological sites, and climate with the park. The Paria has been grazed for over 130 years. Cheatgrass averages less than one percent of the plant community. Native perennials average 93 percent.

Fire, which the anti-ranching crowd expects to restore nature from almost any calamity, is acknowledged by all sane experts to spread cheatgrass on rangelands. Cheatgrass often increases fire frequency until even fire-tolerant native plants disappear. Cheatgrass ãslicksä (vast monocultures of this invader) are the result.

Anyone who loves nature will be pleased to know that native perennial grasses easily replace annual cheatgrass if given favorable conditions. Researchers K. Krabbenhoft, D. Kirby, and Nilson (2000) in North Dakota were successful in two years, using cattle as the control agent. In the intermountain West, cutting-edge ranchers and federal managers concentrate cattle for a brief time (three to 20 days each year) to selectively graze cheatgrass in springtime, when cattle prefer it to perennials. The cattle inoculate the soil with key bacteria and fungi that are also awakened in the soil by the influence of dung and urine. Native seedlings simply wait for the cheatgrass to die in summer. It then acts as a water-conserving, sheltering mulch for natives that mature on summer and fall rainfall moisture. The following spring, cheatgrass seeds (present almost everywhere) do not even germinate in the presence of native perennials and their allied native bacteria and fungi. The cattle are brought back after native seed ripening to plant seed and strengthen the stand. This is a proven management method.

Native perennial grasses and forbs have always competed with shallow-rooted, cool-season annuals like cheatgrass. They have effective strategies and they succeed when livestock imitate the migrating wildlife these plants developed with over many millennia.

According to park lecturers, early writings describe the Virgin River in what is now Zion as a narrow, deep stream lined by meadows (sedges, etc.), with willows on the point bars and cottonwood trees at the edges of the flood plain.

By the 1950s (except where stabilized by engineers), it was a braided stream surrounded by dense thickets of nonnative tamarisks and Russian olive trees. The invaders were much reduced by extermination efforts in recent years. Most riparian systems in the park still vary widely from the potential natural community.

Federal agencies should acknowledge that managed livestock maintain sedge meadows. Livestock removal leads to tamarisk and Russian olive invasions, and loss of stabilizing sedges through shading. Tamarisk and Rus-sian olive drive out willows, too. Agencies should fund studies at landscape scales. They should recognize the validity of clear comparisons of long-ungrazed areas with well-managed, grazed landscapes. Federal agencies should fully inform the courts and correct the legal record when litigants make false claims regarding livestock. They should own up to what has happened ecologically in Zion and other parks.

In the words of Mark Habbeshaw, Kane County, Utah, commissioner: ãRather than allowing bias to eliminate public lands ranching, we should focus on valid science in using and developing proper grazing methods which lead to healthy public lands and sustainable rural economies, cultures, and traditions.ä

Donât get me wrong. I love Zion. Itâs wondrously beautiful. But please donât pretend itâs natural. The place is scientifically important as well, because we donât have to wonder what happens when well-managed livestock are removed from such places÷biological disaster. Integrity requires that people who love nature learn from such examples. If you love nature, letâs work together. We may be running out of time. n

Steve Rich visits Zion often. His family owned land in Springdale (at the south entrance). Heâs watched cheatgrass and other invaders spread for 40 years.

Cheatgrass and juniper crowd out native flowers and grasses.

Cheatgrass invades the space beneath a Utah juniper.

Both contribute to worsening soil conditions.

At this ranch bordering Zion National Park, perennial grasses flourish.

Winter 2005 Contents

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