FULL OF LIFE

FULL OF LIFE The McDowell Sonoran Preserve

Is a stunning landscape: cactuses of every shape and size, bursts of magenta and deep purple and lemon yellow and Kelly green. You can feel the hum of the bees, see cottontails scurry between brittlebushes and hear birds whistle. The preserve receives less than 12 inches of rainfall each year, withstands 50-degree temperature swings between day and night, and can clock a surface temperature of more than 160 degrees in the summertime. The fact that life exists here at all is baffling, even to this longtime Arizonan. What could possibly live in an environment with such hostile conditions? Tucked in a pocket of northeast Scottsdale, the preserve is a protected swath of more than 30,000 acres of the Sonoran Desert. The McDowell Sonoran Conservancy, an organization that studies and maintains the preserve, has identified 417 plant species (including subspecies and varietals) and 599 animal species within its bounds. I'm taking a walk with two conservancy stewards, Dan Gruber and Leonard Marcisz, to learn about this abundance of life amid the challenges - namely, too little water and too much sun - of the Sonoran Desert. This beauty contrasts so radically with the desert's gritty stories of survival. Marcisz makes clear before we start that these species aren't just surviving here; they're thriving. But how? Some have evolved differently than species in more benign environments. Kangaroo rats, for example, have kidneys so efficient that the rats don't need to drink water; they obtain their daily allowance from the seeds they eat. (Imagine taking in enough water for your whole day just from your breakfast toast.) Vultures urinate on their legs to avoid overheating. Other birds dilate blood vessels in their legs to release body heat. Jackrabbits radiate heat from their cartoonish ears. Saguaros, along with other cactuses and succulents, grow a wide, shallow root system, just 4 or 5 inches below the surface, so that when it rains, they can slurp up every last drop. To save energy, teddy bear chollas reproduce asexually, meaning they may bypass the need to flower and be pollinated. Their spine-covered segments are easily dislodged by storms or passing animals, then carried elsewhere to propagate. And some desert plants alter the whole process of photosynthesis by splitting it in two. These plants photosynthesize during the day with closed pores; at night, when it's cooler, the plants open their pores to exchange gases. Other plants and animals have developed strange habits and survival mechanisms to live here, Marcisz says. Kangaroo rats and ringtails, for example, are nocturnal, foraging only after the hot sun has set. In extreme heat, deer and javelinas tend to be crepuscular, active mainly in the coolness of dawn and dusk. Mule deer, graceful champions of the long jump, reproduce four to six weeks later in Arizona than they do in northern parts of their range, a doe timing the drop of her fawn for just before the onset of the summer monsoon, providing water for baby and mother. The barrel cactus, wrapped in what looks like oversized prison barbed wire, is pleated like an accordion and condenses when water is scarce. With rain, it plumps up. It grows thicker skin on its sun-facing side. The desert tortoise has a large bladder that can store more than 40 percent of its body weight, and it stays in rock shelters or crevices to reduce water loss. It, like much of the preserve's wildlife, benefits from the geology and topography of the land, Gruber says.

With flatlands and foothills in the north and a mountain range in the south, animals and plants have a diverse landscape in terms of habitat. Some take up residence on a sunny, south-facing slope; others prefer a north-facing slope, which almost never receives sun. Some head up the mountains, where temperatures are lower. The mountains' drainages also create nooks and crannies where animals can burrow. Couch's spadefoot toads go underground for 11 months of the year, coming up only to mate and collect food - stockpiling and rationing resources, a bit like when we panic-purchased toilet paper. Gila monsters spend 95 percent of their lives underground. Packrats, too, nestle below the surface, but in level areas. And they double or triple their efforts for shade, building a tent of cholla segments atop the entrance, often under the added protection of a tree.

Survival mechanisms abound in the desert. The paloverde tree can perform photosynthesis in its green bark so that when it needs to conserve water, it can drop its leaves. Jojoba plants grow leaves in pairs, so they can shade each other throughout the day. Cactuses don't have leaves at all, but spines instead; the spines provide protection from predators, but also shade and water regulation. Ocotillos, like wild, untweezed eyebrows, can go dormant, expending zero energy, as they wait for precipitation. Creosote, with its miniature-cotton-ball buds, is among North America's most drought-tolerant plants, and its tiny leaves are coated with a fragrant protectant that dissipates in the rain. The saguaro, queen of survival in the desert, demonstrates many of these adaptations. It grows spines, rather than leaves; a broad, shallow root system; and accordion pleats. For a saguaro seed to germinate, it must meet a very particular set of circumstances in terms of rain, tempera-conditions, but it also translates to extreme events such as wildfires, Gruber says. Sparse, well-spaced desert plants naturally prevent fire spread, so when non-native fountain grass or globe chamomile fills in the ground cover, it puts the whole area at higher risk.

A curve of granite frames the preserve's flora and distant mountains in evening light. REBECCA WILKS According to the National Phenology Network, spring has been arriving earlier in recent years. This causes a mismatch in timing between plants and animals. One example: A bird migrates to an area. Its food source is butterfly larvae. Because of climate change, the bird is early. The butterfly isn't around yet, and the bird therefore has no food. Another example: Gambel's quail get their vitamin A from green plant material, which triggers their reproductive cycle and affects the strength of their eggshells. When fewer greens are available in an area, the quail consume less vitamin A, meaning reproduction may not occur or chicks may not survive.

With climate change encroaching, not even these amazing, adaptable species can respond or adapt fast enough, but they try. In 1963, Leon C. Megginson, a professor of management and marketing at Louisiana State University, offered his take on Charles Darwin's On the Origin of Species: “It is not the most intellectual of the species that survives; it is not the strongest that survives; but the species that survives is the one that is able best to adapt and adjust to the changing environment in which it finds itself.” Among the most impressive of animals living in the preserve are hummingbirds, which weigh less than the nickel in your car cupholder. Their hearts beat as many as 1,260 times each minute; their wings flap around 50 times per second. To keep up with this metabolism, they need to drink four to eight times their body weight in water every day. They visit thousands of flowers every day, constantly refueling and seldom stopping to rest. They don't survive because of any superpowers. They survive because they're dogged. And biologists might argue that this extraordinary metabolism, extreme maneuverability and doggedness is an adaptation.

What is the desert, if not a portrait of resilience in action? A signal, right in our own backyard, that we are a product of our environment, that we must be stubbornly perseverant and that we must adapt.

And we do. We grow thicker skin - and spines, sometimes. We conserve resources. We depend on our relationships and lean on our neighbors. We wait, straining our patience, for better conditions. And even when we think it's too extreme, that we can't possibly make it, we, like the hummingbird, just beat our wings and keep going. Our ecological survival converts into something beyond resilience - something that looks a lot like grit.

It looks like a health care worker who shows up for yet another shift. It looks like a circus of squawking children and barking dogs in the background of a conference call. It looks like video chats in place of the clumsy embrace of a grandchild you haven't seen in a year. It looks like the patience of a tired mother, sitting at the kitchen table, trying to home-school her daughter in math.

This terrain teaches us: Eventually, it will rain, and the whole glorious desert will smell of creosote.

For more information about the McDowell Sonoran Preserve, call 480-998-7971 or visit mcdowellsonoran.org. AH

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