by Mary O'Brien, Utah Forests Program Director
The interrelationships of Colorado Plateau wildlife and plants that livestock affect are nearly infinite. Artist Heidi Snyder captures how this intertwining develops via 12 drawings—each a story of interaction and fate.
In three past blogs, we’ve told the story, with the help of Heidi’s art, of how hummingbirds and sage grouse, wolves and aspen, and cutthroat trout and biological soil crusts face challenges amid livestock grazing. This time we look at how northern harrier eggs and the favorite food of cattle—grasses—are linked.
A northern harrier flies above a marshy grassland, which holds its own eggs and many types of prey.
Tall grasses—this is where voles thrive, fawns hide, snakes hunt, spiders hang webs, preying mantises lurk. And this is where young northern harriers (Circus cyaneus) grow inside eggs, nestled in grass-lined nests of cattail, willow, or other thick-stalked plants.
For 28–36 days, the eggs rely on their mother to tend to them. But they also depend on the tall grasses and similar plants called sedges that grow in wet ground to hide them from a host of predators: coyotes, feral dogs, striped skunks, raccoons, red foxes, American crows, common ravens, and great horned owls. After hatching, the young birds seek safety in the grasses for another 14 days.
But cattle eat grasses and sedges to support their 1,200-pound bodies. And in search of that food, they sometimes trample northern harrier eggs and young birds.
Tall grasses provide safe habitats for wildlife, and meals and walking areas for livestock. Where should the balance be?
Squirrel tail, bluebunch wheatgrass, sideoats grama, needle-and-thread, and Sandberg’s bluegrass—a healthy native grassland can feature several bunchgrass species growing side-by-side.
Most of the Colorado Plateau’s native grass species are tall bunchgrasses. Like so many living beings in these arid lands, they live well spaced from each other. Northern harrier chicks take shelter in them. Wildflowers (forbs) and shrubs pop up between them, lizards scurry through the openings, and biological soil crusts hold down the exposed soil.
By contrast, most non-native grasses on the Colorado Plateau fall into two camps: invasive annual grasses, like cheatgrass, or invasive perennial grasses with underground horizontal stems that send up new shoots, like Kentucky bluegrass and smooth brome. Both non-native types tend to form dense monocultures. And they both can take a pounding from livestock hooves and mouths better than our native bunchgrasses.
Here on our Colorado Plateau public lands, perhaps we need to take a look at how we balance tall, waving grasses and bitten-down grass clumps; diversity of native bunchgrasses and monocultures of non-native grasses; grasses as habitat and grasses as forage.
Grass, it seems, isn’t just grass.