Our few remaining native grasslands are under threat from herds of invasive equus ferus caballus, a species introduced to the New World that displaces native populations. The BLM, in part due to a misinformed public, "manages" these herds rather than eradicating them and allowing native species like the American Bison to flourish.
The 35,000 feral equus roaming the American West use a disproportionate amount of water; eat vegetation to the ground; and disturb native populations. In fact, according to a study in Western North American Naturalist, Vol 60, No 3 (2000)*, areas where equus was excluded "exhibited notably greater plant species richness, percent cover, and abundance of grasses and shrubs, as well as more small mammal burrow entrances...". At high elevations, their impact was even more severe: "meadows protected from grazing exhibited maximum vegetation heights 2.8 times greater." Native deer and antelope do not have these effects, and are displaced by equus activity. If you want to see a stark example of the reality of equus overgrazing, the photo shows the difference between an ungrazed native plot; and one where they have been allowed to flourish.
A mechanism for eliminating these invasive equus populations is already in place, but thanks to outside pressure the BLM has refused to take action. I urge you to sign this petition, and help to restore a piece of the American West.