Environment : Strange Endeavor, But Don’t Pooh-Pooh It : Military satellites are scanning Australia’s Outback for a peaceful purpose: to help save valuable rangelands.

MELBOURNE, Australia —  So you thought your tax dollars were being wasted?

U.S. military global positioning satellites, which helped prevent allied soldiers from getting lost in the desert during the Persian Gulf War, are now helping Australian scientists count the droppings of kangaroos, sheep and wild goats on the trackless expanse of the Outback.

“We’re tracking poo by satellite,” explained David Mussared, spokesman for the Commonwealth Scientific, Industrial and Research Organization, a government-affiliated agency in Canberra, the national capital.

He said the scientists are studying the droppings to better understand which animals cause the most damage to fragile grazing and agricultural land on the arid continent.

The point to all this is no laughing matter. About 166,000 square miles of the giant country’s rangelands--an area bigger than the state of California--are now classified as damaged by overgrazing, erosion and salinity, according to the government. The cost is in the hundreds of millions of dollars a year.

For years, arguments have raged here over who is most responsible. Environmental groups accuse farmers and their millions of sheep of overgrazing, while farmers blame a population explosion of red and gray kangaroos. And both groups blame countless herds of wild goats, which eat as much as sheep, destroy more trees than kangaroos and breed almost as fast as rabbits--which, by the way, are also a major problem.

Dr. Jill Landsberg, a CSIRO ecologist, said the three-year study will try to measure the animals’ impact on vegetation and soil in five pastures, each up to 12,500 acres in size. The goal is to develop strategies to sustain and restore the degraded land.

“The question is which animals are doing the most damage,” she said. “We do that by counting their dung.

“We don’t have to pick it up or anything revolting like that,” she added of the field work associated with the project. The rangeland, she noted, “is hot, it’s fly-infested and dusty. But (the work) is really pretty enjoyable. It’s beautiful country and you’re out there all alone.”

That’s where the satellites come in.

A network of U.S.-launched global positioning satellites, long used by oceangoing ships, drew rave reviews last year when allied troops used small receivers in their Humvees to get precise longitude and latitude coordinates in the empty desert during the Gulf crisis and war.

Landsberg’s team uses them the same way in the Outback’s heavy scrub and featureless terrain. Carrying camera-sized, hand-held receivers provided by the Australian Defense Force Academy, or small receivers mounted on motorbikes, she and two other dung-counters take precise satellite fixes on each pile of pellets. They then determine population density and habits of the animals.

“We’re generating detailed computer maps to determine high, medium and low use by each animal,” she said.

“This sort of information is useful when managers are making decisions about where to place new watering points and fences,” she said.

But killing ‘roos is an emotional issue. Australia permits the commercial culling of about 4 million a year, with many used for pet food and leather. The lean, protein-rich meat also is available for human consumption in South Australia, Tasmania and the Northern Territory.

But “Tossing Skippy on the Barbie,” as one recent headline called it, offends many. Kangaroos are on coins and government seals, emblazoned on Qantas jets, the national carrier, and sold as countless cuddly toys for children.

“With millions of kangaroos being killed every year, it is no wonder that the public has become concerned,” the Australian Senate’s Select Committee on Animal Welfare said in a 1990 report. “It should be remembered that the kangaroo occupies an important place in our cultural heritage.”

Although a recent drought has killed numerous kangaroos, the government says the estimated total population of about 18 million is larger than before the first Europeans arrived two centuries ago. Under optimal conditions, one study found, the kangaroo population can increase by 40% a year.

Nor are they always cuddly. In November, 1989, hundreds of huge gray kangaroos were reported rampaging in the quiet Queensland resort town of Woodgate. At least four people needed medical treatment after encountering the rogue ‘roos.

“They roam around in packs of three or four just looking for trouble,” one terrified resident, who required stitches after he was knocked down, was quoted as saying. “They don’t care who they hurt--humans, dogs, cats, you name it. They’re the troublemakers.”