Today, only ghosts know the true name of this hushed place, whispered on breezes that float up through the Tucson Mountains, or down to the Santa Cruz River. But the living call it Los Morteros, a reference to the profusion of volleyball-sized mortar holes in the boulders gathered here. These man-made craters, known as bedrock mortars, once served as vessels for the Hohokam to use for grinding maize and other plants. Like talismans, they dot a landscape that has hosted civilization in one form or another for roughly 2,000 years.

The advancing sprawl of modern man -- traffic, cul-de-sacs, and cinderblock walls -- threatens the timeless aura of this place. A phalanx of stucco, modular, and trailer homes surrounds the 120-acre core of the site; many more perch among the boulders of a nearby hillside.

Sometimes, however, the past and the present manage to find room for compromise.

Which brings us to Loy Neff. It is late afternoon, and the tall, affable archaeologist throws imposing shadows across the flats of Los Morteros. From under the thick brim of a canvas hat, he gazes across this patch of preserved history. He has a right to feel satisfied; along with his colleagues at the Pima County Office of Sustainability and Conservation, Neff pushed hard to save Los Morteros from the triple threat of looters, vandals, and development.

The future of the property -- including whether it would be developed for homes -- was uncertain until 2004, when the county bought it from a local resident for $1.4 million, using voter-approved bonds. “Otherwise, this would have just been back-to-back houses,” Neff says. “That’s how we look at a lot of our preservation properties -- if we don’t get in and get them now, they’re going to be gone forever.”

Before the county purchased Los Morteros, many neighbors viewed it as a problematic, trash-ridden party spot. But today, steel-rail and wildlife-friendly wire fencing and pedestrian gates mark it as a valued place. Inviting the neighbors to help plan for the protection of Los Morteros gave them a sense of ownership, Neff says, and encouraged their vigilance against vandalism.

As Neff talks about this transformation, he treks along what seems a typical desert ridge. But here, first impressions are usually wrong. “This isn’t just a lump of dirt with pottery sherds we’re standing on,” he says. “This actually is a trash mound that’s accumulated over centuries.” The mounds reveal important clues about long-lost cultures, from their tools and pottery to the patterns of settlement in the area.

Neff’s message resonates all across archaeologically rich Arizona, where a skyrocketing population -- a nearly 20 percent increase over the past decade alone -- threatens to overrun the ancient past. New suburbs of Phoenix and Tucson rise atop buried Hohokam villages, and burgeoning populations tread through once-remote ruins. “Up near Phoenix, a lot of petroglyphs have already been shot up,” says Andy Laurenzi, field representative for the nonprofit Archaeology Southwest. “Those areas have taken a beating.” Meanwhile, professional looters ravage sites across Northern Arizona for Anasazi artifacts, which can garner huge sums on the black market.

Fortunately, plenty of folks -- both newcomers and longtime Arizonans -- are equally dedicated to protecting the state’s priceless heritage. They range from watchful Forest Service rangers to professional archaeologists such as Loy Neff to an army of trained volunteers monitoring sacred sites. All of those efforts have legal bite, as well, rooted in the National Historic Preservation Act of 1966. State and local preservation laws likewise make artifact theft a crime, and require that development projects mitigate their impacts on cultural remains.

The very need for such laws underlines the ongoing clash between past and present. “Where people want to be -- such as riparian areas -- is also where prehistoric man was,” says James Garrison, Arizona’s state historic preservation officer. “So you have this interface that’s bound to collide at some point.”

Garrison’s post is designated under the federal preservation act, which his office -- a division of Arizona State Parks -- invokes whenever large development projects threaten historically or culturally significant resources.

If cultural remains are discovered, archaeologists commonly excavate and sample the site. These reviews may then compel changes in development plans to better protect particularly important areas. This complex process can involve everyone from scientists and local governments to sovereign Indian nations. “There’s a lot of negotiation between the tribes, the federal agencies, developers, and in a lot of cases the state land department,” says Garrison.

Native American community leaders often play a principal role in the preservation of their ancestral sites. Most tribes employ their own archaeologists to help protect ancient places they consider sacred. “There are a lot of beliefs and traditions incorporated in those archaeological sites, be they Anasazi or Hohokam,” says John Lewis, executive director of the Inter Tribal Council of Arizona, Inc. “Some tribes can trace back directly to the areas and villages. Sometimes those places are even a part of their migration stories."

All of this back and forth among different groups can lead to notable preservation successes. For instance, at Anthem, a suburban community created in the late 1990s on the northern flanks of Phoenix, developer Del Webb reconfigured plans so it could preserve many of the most concentrated archaeological sites. “They did a survey, so they knew what the archaeology was,” Garrison says. “Then a number of sites were avoided and instead worked into golf courses and open space and green areas, to preserve them without having to be excavated."

And in western Tucson in 2000, the Arizona Department of Transportation (ADOT) funded a $1 million excavation of the Julian Wash, a site containing as many as 1,000 prehistoric Hohokam dwellings. The land happened to sit directly in the path of a planned $60 million, three-level freeway interchange. For the first time, ADOT set aside part of the construction zone to be used as an archaeological preserve, creating the Julian Wash Natural and Cultural Resources Park. In recognition of its efforts, the agency received a state preservation award.

So numerous are Arizona’s archaeological treasures that nobody ventures a precise count. But the state does count on 900 volunteers who monitor some 1,600 sites. Organized through the Arizona State Parks, these site stewards act as the eyes and ears for land managers from Pima County to Northern Arizona’s Coconino National Forest. They’ve also pulled some spectacular coups -- such as nabbing a notorious developer who, in 2003, wantonly bulldozed several Hohokam sites dating to A.D. 500. Sued by the Arizona attorney general, the developer ultimately paid a $7 million settlement to the state. (Contractors involved paid an additional $5 million.)

But it can be sensitive work, too. For instance, when volunteers witness looting or vandalism, “they are told not to engage,” says state volunteer coordinator Nicole Armstrong-Best. “They are told to call the land manager or the authorities.”

And call they do. Arizona’s program is considered a national model for good reason: In a typical year, stewards report roughly 250 vandalism incidents.

Other volunteers keep watch independently. Among them is Joe Vogel, who moved to Prescott, Arizona, in 1987, following his retirement from Eastman Kodak. He now spends his days patrolling old sites -- and discovering new ones -- from the cockpit of his 1967 Citabria airplane.

The octogenarian has photographed more than 900 sites from 1,000 feet in the air. His more-significant finds include landscape anomalies that led to the identification of prehistoric sites in the Agua Fria National Monument 40 miles north of Phoenix. “If I see some vandalism, I try to photograph the site again,” he says, “to see if there has been new damage to it.”

But even the most dedicated stewards can only protect their sites to a point. That makes another key element -- public education -- even more crucial. “If people aren’t educated about the importance of these resources, then they don’t know why they should care -- and why they should help to preserve them,” says Dr. Patrick Lyons, director of the Arizona State Museum (ASM) at the University of Arizona in Tucson.

While institutions such as the ASM and Flagstaff’s Museum of Northern Arizona now offer archaeology programs, policy makers are also stepping up efforts to preserve the past. A push to designate Southern Arizona’s Great Bend of the Gila as a National Monument, for example, has drawn support from U.S. Rep. Raúl Grijalva, D-Ariz., and a number of Native American tribes.

At an archaeological site known as Indian Town on the ramparts of Catalina, Arizona, a torn garbage bag’s contents -- bottles, newspapers, diapers -- spill across the desert like disgorged bowels. There’s a mattress off to one side, a red carpet of spent shotgun shells on the other.

The land that makes up Indian Town once hosted a huge Hohokam settlement. A rock wall dotted with petroglyphs forms an etched mosaic that includes otherworldly intaglios of men, beasts, and what appears to be a bird in flight. Once again, that uneasy juxtaposition -- ancient and contemporary, relic and castoff -- inhabits this contested space. Though the site occupies state trust land and is technically closed to the public, it’s now routinely visited by vandals, professional looters, and careless off-roaders. Graffiti mars the petroglyph wall.

Farther up the road, Robin Rutherfoord stands over a four-foot hole in the ground, from which thieves recently tugged an enormous bedrock mortar. A trained archaeologist, she coordinates volunteer site stewards for Southern Arizona.

“Many people who come here don’t even realize they’re on an archaeological site,” Rutherfoord says. “A lot of other people think it’s really fun to go out and shoot at petroglyphs. Some will even take a saw and cut pieces from the stone.”

In 1979 and 1980, faculty and students from Pima Community College excavated part of this site and inventoried much of its contents. But little care was taken of Indian Town after that, and it quickly became the domain of pot hunters who collect artifacts for personal gain. A steward comes out here two to three times a month, but he still can’t keep tabs on all the damage.

Rutherfoord, like Patrick Lyons, believes the long-term answer lies in educating folks about why the past is worth protecting. That, and maybe a few tougher laws. In the meantime, her stewards will continue their vigil.

“Our presence might help keep some people from coming in and shooting up a site or digging it up or whatever,” she says. “If someone shoots up a petroglyph or digs up a site, we know there’s a change going on out here. And if there’s a change, we know to get out and monitor the site more frequently.

“Hopefully,” she adds, “just with someone’s presence out there, it’s a way of deterring people from doing things they aren’t supposed to do.” Until a day of stronger legal protection and widespread educational programs, the keepers of Arizona’s ancient past are counting on just that.