John Ruhs, the Bureau of Land Management’s director in Nevada, helps oversee 37,700 wild horses and burros roaming federal lands in the state, more than three times the number the agency has determined the ranges there can sustain.

Nevada bears the worst of a problem trampling the West, with more than 72,000 horses occupying BLM-managed lands as of March, almost 300 percent more than the 26,715 the agency says it can control in an environmentally sustainable manner.