Sheep being employed against invasive species

Sheep are being used as a new, environmentally friendly weapon to slow the spread of invasive species. Pamela J. Podger of The New York Times writes, "Nationwide, sheep grazing is gaining popularity as a low-cost, nontoxic tool in the battle to control leafy spurge, knapweed, dalmatian toadflax and other invasive weed species."(Times photo by Janie Osborne)

Invasive species are taking over public lands throughout the U.S. The Cornell University College of Agriculture and Life Sciences found that "nonnative weeds had invaded 40 percent to 50 percent of America’s croplands, pasture and public lands and were spreading at a rate of 1.75 million acres per year," Podger notes. Grazing is seen as a way to combat this trend without using fossil fuels but gaining the added benefits of producing wool and meat.

The practice has its detractors. "Giles Thelen, a plant ecologist at the University of Montana in Missoula, said that results of the sheep grazing program were anecdotal and that plots should be used to measure how effective the sheep were," writes Podger. "Thelen also worries about the sheep worsening the problem by picking up invasive seeds in their wool and dropping them in new areas, as well as causing erosion with their hooves."

The city of Missoula pays a rancher $1,300 a month to graze his flock of sheep on public lands. Those lands are 75 to 100 percent invaded by noxious weeds according to Morgan Valliant, Missoula’s conservation lands manager. While many argue that herbicides are more effective in dealing with the invasive species, many resist using poisons on public lands. (Read more)