Published in Arizona Highways, June 2009

Driving up the Catalina Highway on a summer morning, there comes a sudden rockslide of memory: Back to the summer of ’74, where my wife Patty and I are wedged into a minuscule pullout at the side of this same road, our brand-new Fiat roadster wrapping itself in a cloud of steam. It had seemed alluringly romantic, a spirited top-down drive up the big mountain on Tucson’s northern flank, watching the desert scenery blur into piñon-juniper woodland and then alpine forest. But the Fiat is having none of our romance. It will take two more attempts before a cooling-system improvement gets us to the mountaintop without overheating.

But now it is 2009 and everything has changed. The road is wider and luxuriously outfitted with pullouts and guardrails, and the Forest Service charges $5 for the drive. The mountain no longer serves as Tucson’s northern boundary; the city has lapped around it in the shape of a lopsided horseshoe. In 2003 the month-long Aspen Fire scorched 132 square miles of the mountain’s forests. I am no longer as interested in driving up the mountain as in hiking through it. And Fiat no longer sells cars in the United States.

Consider these changes in the context of geologic time, and they seem astonishing. And there are more coming, quickly. The tribe seething around the mountain’s skirts, now more than a million strong, has profoundly altered the mountain’s character. It seems like time to sound an alarm: Civilization is messing with an ecosystem that’s still too complex for us to be able to predict the consequences. But first it’s worth looking at how this mountain has messed with us.

For as long as there’s been recorded history, the Santa Catalina range has represented escape. Most obviously, from the desert heat: In the 1920s, editorial writers for the Tucson Citizen and The Arizona Daily Star pecked out rival editorials pushing, respectively, a paved road and an alpine airport for the mountain. Reluctant voters twice rebuffed $500,000 bond proposals for the highway, and the airport never got off the ground. But in 1933 the Citizen’s publisher, Frank H. Hitchcock, embraced the prospect of prison labor to build the road, and with his influence, work on the 25-mile-long highway began just three months later. The mountain resisted more than anyone expected. By the time the road ended in the ponderosa pines, it had taken 18 years, 8,003 federal prisoners, and even with all that free labor, nearly a million dollars.

A few determined pioneers built a town at the end of the road—Summerhaven, which until the Aspen Fire was a motley scattering of cabins with a year-around population of about 50. It would have grown larger, except that there was only 240 acres of private land, surrounded by Coronado National Forest. (Post-fire, Summerhaven is still tightly contained, but the “cabins” are being replaced by serious haciendas that just happen to be built out of logs. “Some of them have elevators!” an incredulous contractor confided.)

On the lower flanks of the mountain, there’s been nothing to stop Tucson from oozing into the foothills, right up to the National Forest boundary at about 3,500 feet. People who built in these heights won no reprieve from the desert heat, but when I was a reporter in Tucson in the 1970s and controversy was raging over the growing crust of foothills houses, I interviewed a psychologist who suggested people were trying to escape something even more onerous: mortality. “Snuggling up to something permanent,” he said, “seems to offer us a connection to permanence ourselves.” No dummy, he lived in the foothills himself.

As Tucson surges around the mountain, people are now escaping the crush of urbanity. On a perimeter drive around the range—an improvised 92-mile loop that at this point still includes some dirt roads and bullet-ventilated highway signs—I stop at Saddlebrooke Ranch, a new “resort community” that will build out to 5,800 homes. “We’ve got boomers coming out of the woodwork,” sales consultant Frank Caristi tells me. “Most of them are coming for the peace, quiet, serenity, and views of the mountain.”

Although Saddlebrooke Ranch qualifies in spades as urban sprawl—it’s a 35-mile expedition to downtown Tucson—I understand the impulse. The last house I occupied in Tucson squatted in the foothills, on a site as close as I could afford to the mountain’s southern flank. The Catalinas filled the windows, an ineluctable reminder of the towering dominance of nature. This is the most profound thing the big rock provides for Tucson: perspective.

“We do not know who we are until we look at the mountain,” Charles Bowden declared in his ode to the Catalinas, Frog Mountain Blues. I have chewed on that for 20 years, since the book first appeared. It seemed extreme—Bowden always is. Do people in Dallas or Paris not know who they are, lacking a handy mountain for reference? But that book prompted me to begin hiking in the Catalinas, and then I began to understand what a miracle it was to have a mountain bursting out of your city, a mountain in the backyard, a way to understand civilization in its real perspective in nature.

One Sunday at dusk, a Tucsonan named Bill McManus was plodding the Ventana Canyon trail some 1,000 feet above the city when he saw the tawny flash of a golden retriever ahead on the trail. Except that when he closed to about 40 feet, he realized it was not a canine but a cat: a mountain lion.

“I waited for it to run away,” McManus told me. “But it just stood there watching me. I tapped my pole against a rock. It walked off the trail, squatted, as if it was waiting for me to pass. It was acting more like a dog or somebody’s pet than a wild animal.”

McManus said he was fascinated, but when the cat slipped into some tall grass and he couldn’t see it any more, “I got a little worried.” He shouted, rapped on rocks with his hiking stick, and retreated down the mountain—wasting no time, but wisely not running.

McManus’s encounter encapsulated the collision of nature and civilization now occurring on Tucson’s backyard mountain. The big rock inspires us, entertains us, frightens us. In turn, we are remodeling it, sometimes inadvertently, through our presence on it and around it.

The best way to think about a desert mountain is as a “sky island,” an ecosystem dramatically different from its surroundings. There are about 40 ranges tall enough to qualify as islands in the Sonoran and Chihuahuan deserts of the U.S. Southwest and adjoining Mexican states, and the Catalina range, peaking at 9,157 feet, is the third highest. And it’s the only one in Arizona with a major urban area around it.

Ringing the mountain with roads and subdivisions has enormous implications for wildlife. Large mammals, such as bears, mountain lions, bighorn sheep and mule deer, become isolated on their island, with no way to migrate through desert and grassland to other mountains. With shrunken territory and lessened availability of mates, their numbers decline—most dramatically among bighorn sheep, which numbered about 170 in the Catalinas in the 1970s. The last verifiable report, in 2004, counted six.

Climate change, apparently the consequence of an energy-hungry civilization, is profoundly affecting the biology of the island. Bark beetles, encouraged by drought and higher temperatures, are killing increasing swaths of high-elevation forest, principally piñon and ponderosa pines. Some animal species appear to be migrating up the mountain. A Summerhaven store owner told The Arizona Daily Star she’d started seeing roadrunners in the neighborhood—an elevation of 8,200 feet.

Matt Skroch, executive director of the nonprofit Sky Island Alliance, told me in his Tucson office that climate change, more than anything else, is what keeps him up at night, worrying about the mountains. “The species that occur at the highest elevations, where do they go? The spruce-fir habitat supports thousands of species. What happens when that habitat gets pinched off the mountains?”

Biologists are also losing sleep over a seemingly mundane pest—African buffel grass, a tough, knee-high, shrubby exotic that over the past decade has rapidly begun clawing into the foothills of the Sonoran Desert mountains. It’s choking out native species and ferrying fire toward the forests. Probably the only way to challenge it is with massive chemical warfare, which will of course affect the entire ecosystem in unpredictable ways.

This is the short view, and it’s dismaying. But there is a long view, and its spokesman is an articulate Forest Service biologist named Josh Taiz. He grew up at the foot of the Catalinas, majored in evolutionary biology and ecology at the University of Arizona, and now works in a cramped office at the back of the visitors center at Sabino Canyon. Early on a summer morning, we take a little Kawasaki trucklet up to a foothill perch where we can look into Sabino’s yawn and across the craggy face of the Catalinas.

“I’m not sure we can say the Catalinas are ‘healthy’ or ‘unhealthy’ because we don’t have a baseline of what constitutes the ‘health’ of the ecosystem,” Taiz says. “Adaptation and natural selection are at work constantly. Certain species will thrive in certain conditions, and in others they won’t. What we’re seeing now is that these biological communities are changing—no question about that. We often automatically tag that as ‘bad.’ It may well be. But when I hear ‘bad,’ I say, ‘maybe.’ Wait and see.”

Taiz sketches a portrait of a mountain ecosystem—really, a network of ecosystems—so complex that it still defies modern science’s ability to predict and explain its behavior. For example, he cites the Aspen Fire, whose vast and obvious destruction has yielded some unexpected benefits for wildlife. “The Mexican spotted owl—intuitively, you would have expected the fire to have devastated it, since it took so much mixed conifer forest. But 2003-04 produced the largest number of young since the early ‘90s.” The apparent reason is that opening up the forest canopy and increasing mulch benefited small mammals. Their numbers boomed, which in turn encouraged their predators: the owls.

We peer across the canyon at the waves of houses lapping against the mountainside. Chipmunks, Taiz notes, thrive in the vicinity of humans. This ripples throughout the food chain. The rodents eat the eggs of ground-nesting birds, which may cause them to decline. Raptors swoop down onto the chipmunks, which may give the big birds a boost. Where it all ends, nobody knows. “Eventually the system takes care of itself,” Taiz says. “Maybe not in our lifetime.”

It’s reassuring that a biologist thinks this. Just as the mountain itself is a reassuring presence. That, in fact, is the core of its importance for the messy carnival of humanity teeming around it. The mountain tells us that as there has been a past, there will be a future; and that our mistakes, in the very long view of nature, might be forgivable.