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Yellowstone’s recovery: Lessons for the West

Yellowstone’s recovery: Lessons for the West
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New scientific findings reveal that the reintroduction of wolves in Yellowstone and subsequent changes in elk grazing patterns have triggered a resurgence of vegetation and wildlife diversity, offering us a powerful lesson in ecological renewal. But hidden in this story is a path forward toward better management that could help us achieve healthier lands and wildlife on public lands throughout the West.

When wolves were brought back to Yellowstone, it was like hitting an ecological reset button. After native predators were killed off by park managers around the turn of the 20th century, elk populations expanded far beyond the carrying capacity of their habitats. The resulting overgrazing decimated young aspens as well as cottonwood saplings and willow thickets along the streambanks. With the elimination of broadleaf plants, beavers disappeared from streams and rivers, disrupting the natural hydrology that supports stream health and the productivity of bottomland meadows.

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The return of wolves has recalibrated elk distribution in the park, helping to return the natural balance of the ecosystem. The resulting recovery of streamside willows and cottonwoods has led to a resurgence of beavers and streamside songbirds. Yellowstone’s recovery remains far from complete, but the vibrant resurgence of healthy natural systems in the span of a few short decades is astonishing.

The overgrazing caused by elk in our nation’s first national park has a parallel in the longstanding and systematic overgrazing of cattle and domestic sheep over the vast majority of public lands across the West. As a result, our western rangelands are painfully degraded, and their poor health compromises their resilience in the face of unprecedented changes in climate.

Cattle evolved in the lush, productive meadows of rainy northern Europe. Transported far from their native habitats to the arid deserts and rugged mountains of the West, they concentrate along watercourses, wiping out streamside vegetation and degrading water quality and fish habitat. Like the formerly overpopulated elk in Yellowstone, cattle suppress aspen and cottonwood saplings, and decimate streamside willows.

Land managers typically allocate half of the annual grass production to livestock. That leaves only half of the annual growth of grass for native grazers like elk and deer, and for small mammals like rabbits and mice (which often collectively consume large volumes of plants), and for insects including grasshoppers and Mormon crickets with their periodic population surges, and — most importantly — for the survival and reproduction of the grass itself.

Livestock initiate a cycle in which native perennial bunchgrasses, which are nutritious and preferred by both wildlife and livestock, are killed off and replaced by invasive weeds that colonize disturbed habitats.

Rangeland deterioration accelerates as cattle compact soils and trample the fragile soil biocrusts that are so important to maintaining water and nutrients in arid desert soils. The most prominent weed is cheatgrass. This invader from Eurasia crowds out native grasses during its brief annual lifespan, dies to become flammable tinder, and then fuels unnaturally frequent and severe fires that wipe out the sagebrush communities that form the basis for so many native wildlife species, from pronghorn antelope to pygmy rabbits to sage-grouse.

Several years ago, the Wyoming Game and Fish Department held a seminar on their official policy never to use the word “overgrazing,” for fear of losing access to private ranch lands. While a startlingly candid revelation, it is symptomatic of a broader trend among land and wildlife managers to turn a blind eye to the ecological damage from domestic livestock. We need to start talking about these problems if we ever hope to fix them.

We should address livestock problems to restore the ecological balance, and the West will be better for it. Allowing predators to reoccupy the landscape and exert their natural influence on prey populations is one part of the solution. Substantially reducing livestock use in deserts and mountain ranges is another. Maintaining wildlife corridors and connectivity among healthy landscapes will foster the expansion of Yellowstone’s success.

Achieving the long-term gains of healthy lands, abundant wildlife, and clean cold waterways filled with trout on public lands far outweigh any short-term pain that such adjustments might cause for commercial users.  Giving natural systems a break from livestock use also supports their resilience to withstand the accelerated cycles of drought and fire that the West now faces. Now, more than ever, we need to hit the reset button and restore public lands to a vibrant, healthy state.

Erik Molvar is a wildlife biologist with scientific publications on moose behavior and ecology, and serves as Executive Director of Western Watersheds Project, a nonprofit group dedicated to protecting watersheds and wildlife across western public lands.