An end to Tucson’s growth wars

A conservation plan puts science ahead of politics.


As the small Cessna airplane flies above Tucson, its passengers see the rugged, low-lying Tortolita Mountains to the east, followed by the huge green blocks of cotton fields. Over to the west, the bright blue Central Arizona Project canal slices through the desert. Farther south rise the untrammeled desert mountains of Saguaro National Park-West.

This aerial view showcases both the conservation successes and failures in the Sonoran Desert surrounding Tucson, whose population totals about 1 million. In the past 17 years, Pima County has spent nearly $200 million, raised through voter-approved bond issues, to preserve more than 200,000 acres of deserts, mountain parks, riparian areas and grasslands. Though red-tile roofs dominate much of the land, which is surrounded by five publicly owned mountain ranges, you can still see plenty of open desert dotted with dark green mesquite and palo verde and gray-green cactus.

The county’s preservation efforts have also put it in the cattle business. The protected lands include 140,000 acres on which the county controls grazing leases. Ranchers who once feared that their remote mesquite flats and grasslands would be gobbled up by speculators still ply their trade, albeit with much-reduced cattle numbers.

All of this is thanks to one of the most aggressive and ambitious urban land conservation efforts ever undertaken in the Southwest. Approved in fall 2016 by the U.S. Fish and Wildlife Service after nearly 20 years of work, Pima County’s Multi-Species Conservation Plan transformed the politics of a region that was infamous for endless sprawl. It protects dozens of vulnerable species and conserves biologically sensitive lands while permitting development on other lands, thereby ending conflicts over growth that had dragged on for decades. The plan has become a national model, drawing praise from scholars, land planners and environmentalists around the country — particularly for the way it insulated scientific input from political considerations.

“It remains critical that scientists working on a conservation plan — or any project for that matter — be relatively isolated from political pressures,” says Reed Noss, a conservation biology professor at the University of Central Florida, who worked on a county-funded peer review of the plan back in 2001. “Scientists still must take into account political realities, so that what they produce is relevant and feasible. But they should not be pressured.”

  • A gas pipeline, seen as a light-colored line, disrupts the natural washes and habitats in the Sonoran Desert.

    Jordan Glenn with support from LightHawk Flights
  • The Santa Rita Mountains

    Jordan Glenn with support from LightHawk Flights
  • A new development in Oro Valley encroaches on existing conservation land near the Catalina Mountains.

    Jordan Glenn with support from LightHawk Flights
  • In an effort to work with the land, housing developers designed this Oro Valley community around a natural wash. This has not completely solved the problem though, as many animals won't go near the development.

    Jordan Glenn with support from LightHawk Flights
  • The shadow of a LightHawk plane is seen on the desert floor.

    Jordan Glenn with support from LightHawk Flights
  • Housing developments in Arizona’s Green Valley and Oro Valley disrupt the habitats of endangered species such as the pygmy owl and bighorn sheep.

    Jordan Glenn with support from LightHawk Flights
  • A land bridge constructed over Oro Valley Road in Tucson makes it easier for animals such as bighorn sheep to cross safely from one protected area to another.

    Jordan Glenn with support from LightHawk Flights
  • Green Valley developments sit on the edge of Canoa Ranch Conservation Park, one of the largest open-space purchases in its history.

    Jordan Glenn with support from LightHawk Flights
  • The San Pedro River riparian area is a crucial piece of protected land and provides shelter to hundreds of bird and animal species.

    Jordan Glenn with support from LightHawk Flights
  • Raven Golf Course and the Sabino Springs housing development reach into the canyons of the A7 conservation area, threatening the home of hundreds of species that rely on the natural canyon ravines to migrate.

    Jordan Glenn with support from LightHawk Flights

Pima County’s habitat conservation plan grew out of a culture of runaway development and extreme political conflict. The catalyst was the 1997 federal endangered species listing for the cactus ferruginous pygmy owl, a small raptor whose desert-wash habitat was imperiled by development and groundwater pumping. Until then, the county had routinely approved major rezonings for well over two decades, despite opposition from local environmentalists. At the time, the desert was being paved at the rate of an acre every two hours, pushing Tucson’s suburbs toward the edge of the surrounding national forest and parkland.

The pygmy owl’s listing resulted in significant growth restrictions. Hoping to avoid similar controversy and litigation over other species, Pima County Administrator Chuck Huckelberry and his staff, prodded by environmentalists, started work a year after the listing on a long-term Sonoran Desert Conservation Plan to protect the county’s natural and cultural resources. As part of that effort, they developed a plan to protect dozens of imperiled species. To determine which lands were most essential to wildlife, they created a “firewall” around a committee of scientists, insulating them from political pressure. “County leaders stated from the outset that their primary goal was to conserve biological diversity through a scientifically defendable process, not to come up with a plan that everybody could agree on,” wrote the late urban planning specialist Judith Layzer in her 2008 book Natural Experiments, which analyzed more than a half-dozen regional land-conservation efforts.

The scientists and county staff discussed the plan in public sessions, but county officials made it clear that their work would not be derailed by complaints from developers and other critics. The scientists established standards for identifying biologically valuable lands and used computer models, observation records and the judgment of local naturalists and recognized experts to come up with a biological preserve map.

In contrast, in other multi-species plans, scientists, politicians, agency staffers, developers and moderate conservationists collectively determined which lands to save, thus bringing political and economic considerations into the science.

Looking back this spring, Huckelberry, a former county transportation chief, says he was simply applying the best practices from his previous job, highway planning, to land conservation. Typically, both a technical committee and a citizens’ committee review big road projects, he says: “The whole purpose of a technical advisory committee is not to play with the numbers, not to slant the analysis. We felt the political side could potentially be used to manipulate the scientific side, and felt that would bias the entire process.”

After the science team created a map of the proposed preserve system, a separate steering committee of 84 people, including developers, environmentalists and neighborhood leaders, haggled over its details. By then, though, the plan’s broad vision was already solidly in place.

The scientists’ work led to the creation of the Conservation Lands System, 3 million acres of picture-book Sonoran Desert, grasslands and riparian areas, with about 60 percent of it preserved as open space. Nine of the 44 vulnerable species protected by the system are on the federal endangered species list, including the Gila topminnow, the western yellow-billed cuckoo and the Pima pineapple cactus.

In 2003, the county took another major step by folding the multi-species plan into its broader Sonoran Desert Conservation Plan, which calls for conserving ranches, protecting culturally and historically sensitive properties and expanding an existing mountain park network.


Developers, homebuilders and realtors initially howled at the proposed multi-species plan, but backed off after winning two concessions. First, Huckelberry promised not to propose additional land-use regulations. Second, the county agreed to give small landowners more leeway, because their projects have much less impact. “As soon as it was clear it was going that way, most of the opposition from private-property owners dissipated,” says realtor Bill Arnold, leader of a vocal property-rights movement.

The plan’s backers say it also benefits developers. Within the million-acre area governed by the county’s federal Endangered Species Act permit, landowners who sign up for voluntary coverage under the plan are then exempt from prosecution for unintentionally killing or harming any federally protected species on their property. If any of 35 other species are later placed on the endangered species list, the landowners won’t be subject to new restrictions. The plan may also exempt them from protracted biological reviews if their projects need a federal Clean Water Act permit.

Coverage under the multi-species plan is “an insurance policy,” says Jenny Neeley, the county’s conservation science program manager. “It comes down to risk assessment.” If there’s a chance any of those 44 species might be on a landowner’s property, they’d do well to sign up for coverage, which costs from $720 to $3,160 per development project. (Builders of individual homes don’t have to pay.)

Whether they opt into the multi-species plan or not, all builders must also comply with tough county rules protecting riparian areas, native plants and hillsides, including a requirement to preserve at least 65 percent of sensitive lands. “It’s better than what we had anticipated,” says David Godlewski, president of the Southern Arizona Homebuilders Association, adding, “We still maintain that Pima County has some of the most restrictive environmental policies in the U.S.”

Layzer’s 2008 book called the overarching Sonoran Desert Conservation Plan the most effective federal habitat conservation plan in the West: “Overall, (it) has shifted the status quo in Pima County from unfettered development accompanied by protection of isolated parcels to managed growth and landscape-scale conservation.”


Yet the county’s plan has limits to its power and scope, and now faces new challenges. In a huge swath of desert grasslands southwest of Tucson, for instance, some of the county-owned ranchlands now are crossed by an underground natural gas pipeline, which left a scar on the land and may increase soil erosion.

And in some of the prime foothills areas, tile roofs now dominate land that environmentalists had hoped to conserve; it has been rezoned for high-intensity development. And east of Tucson along the San Pedro River, a $2 billion power line project could damage grazing lands and riparian areas.

Environmentally speaking, it will take years of monitoring the protected lands to determine if the multi-species plan meets its goals. And drought and climate change could threaten the land’s future health. “Anytime you look at conservation on a landscape level, you take a chance that you are not hitting the right target,” says Carolyn Campbell, director of the Coalition for Sonoran Desert Protection, which led the charge for the Sonoran Desert plan. “But I will say that conservation has already happened here, because of land set aside in perpetuity.”

Economically, the plan has been an absolute success, county administrator Huckelberry says. In the past year or so, the county says it has landed about 5,000 new jobs, with little environmentalist pushback. The jobs are generally not planned for sensitive lands, but more importantly, the preservation of so much open space has muted what would have been fierce opposition to some of the projects involved. Acquiring open space, Huckelberry says, “has really ended the growth wars.”

Tony Davis writes for the Arizona Daily Star in Tucson.

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