Friday, October 17, 2014

Livestock grazing is no friend to rangelands

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By GEORGE WUERTHNER

    I would like to response to John Peavey’s assertion (Guest opinion, Oct. 10, “Watching grass grow—how exciting is that?”) that grazing benefits Idaho’s rangelands. As a rancher, Peavey’s comments are self-serving as well as lacking in ecological understanding.
    First, bluebunch wheatgrass, one of the common perennial grasses on Idaho rangelands, are long-lived plants. In a sense, most perennial grasses can be thought of as “old growth grasses.” They only produce successful seedlings infrequently, but that is OK because they live 100 years or more. In order to replace themselves on rangelands, they only need an occasional good year for seed production and seedling establishment. But the years when such conditions exist are unpredictable and infrequent. If perennial grasses are grazed by livestock during that year, it may eliminate the only successful replacement cycle for years or even decades. Over time, a few missed good seed years lead to rangeland degradation—which is exactly what has happened to Idaho grasslands.
    Grazing does not benefit grasses. It harms them just as humans do not benefit from being cut or battered. We have the ability to recover, but only if we are not experiencing continued abuse. It’s the same for grasses. When cropped by a cow or sheep, the grass shifts energy from production of roots and seeds to new leaves since it needs new leaves to photosynthesize. Repeated grazing, even if spaced by several years, gradually wears down the plant’s reserves. Unfortunately, because most Idaho rangelands are grazed every year, and/or even alternative years as under the rest-rotation grazing Peavey champions, most native grasses never have time to recover from grazing events. And if that once-in-a-decade-or-so good conditions for seed production and establishment come along, native perennial grasses like bluebunch wheatgrass may not have the energy to produce seeds. That is why Idaho’s grazed rangelands continue to decline in ecological vitality.
    By contrast, annual grasses like cheatgrass are designed by nature to produce seeds every year. When rangelands are grazed, it favors the annual grasses, which are adapted to rapid seed production and seedling growth. Grazing by livestock further favors cheatgrass by trampling of soil biocrusts—lichens, algae and mosses—that reduce soil erosion, add important nutrients and most importantly preclude the establishment of annual grasses like cheatgrass. By contrast, the seeds of native grasses are adapted to biocrust, and long intervals between successful seed years. All one has to do is visit the places where livestock have been excluded, whether by law or by natural barriers (like grass islands in lava flows such as at Craters of the Moon National Monument) to see that native grasslands thrive in the absence of domestic livestock grazing.

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    George Wuerthner is ecological projects director at the Foundation for Deep Ecology.

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