By Molly O'Toole
WASHINGTON (Reuters) - Wild horses on the vast rangelands of Wyoming can continue to roam free, for now, after the U.S. government's Bureau of Land Management postponed a planned roundup, horse advocates said on Tuesday.
The roundup was due to start on August 16 to reduce horse overpopulation on more than 700,000 acres of public land in Wyoming, but the federal agency agreed to put it off until at least September after facing a lawsuit.
The bureau had planned to remove 700 wild mustangs in southwestern Wyoming and return 177 geldings or castrated stallions to the land, according to the lawsuit filed July 25.
The plaintiffs -- the American Wild Horse Preservation Campaign, the Western Watersheds Project, a Wyoming couple and wildlife photographer Carol Walker -- accused the BLM of intending to "manage the wild horses to extinction."
They argue that the agency is violating the 1971 Wild Free-Roaming Horses and Burros Act, which mandates the BLM to protect and manage the animals as "symbols of the historic and pioneer spirit of the West."
"The BLM informed the federal district court judge ... that it has decided to withdraw the final decision that authorized the roundup," said the plaintiffs' attorney Katherine Meyer.
Wild horse advocacy groups have called for a moratorium on all government roundups of wild horses, saying roundups could pose irreparable harm to America's wild horse populations.
The BLM says that is untenable because herds can double in size every four years and overpopulation causes soil erosion, sedimentation of streams and damage to wildlife habitats.
"The ecosystems of public rangelands are not able to withstand the impacts from overpopulated herds," the bureau said on its website.
A BLM spokesman declined to comment on the Wyoming case.
The BLM estimates that 38,500 wild horses and burros roam on rangelands it manages in 10 western U.S. states and herd sizes grow at an average of 20 percent each year due to a lack of natural predators.
(Additional reporting by Ruffin Prevost; Editing by Anthony Boadle)