72 TUCSON LIFESTYLE / April 2020 TucsonLifestyle.com last call for the he fading daylight and steady drizzle make it hard to see the Native Southwest plants hole in the trunk of the mesquite tree that we have been watch- and animals are rapidly ing for the last half hour in hope of hearing or seeing the owl disappearing from our we believe will come out for the evening. My husband Ben and wild?I are in northwest Tucson, having spent the day on this site area of the state. Jennifer ttagging saguaro and barrel cacti, mesquite, palo verde, and ironwood Patton, a local landscape trees as part of a native plant inventory, required prior to the site being architect, and her husband graded for a proposed residential development. During the day we startled a large covey of Gambel’s quail, observed a red-tailed hawk and business partner constructing her nest in a multi-armed saguaro, flushed a pair of great Ben Wilder investigate horned owls from an immense and ancient foothills palo verde tree, the reasons why, and and surprised a small flock of reclusive black-throated sparrows. And toward the end of the day, as we were tying a red flag around the what can be done to stop branch of a mesquite slated for removal, we noticed movement inside a the extinction. cavity of the tree. Something feathered and gray, watching us. We have never seen a cactus ferruginous pygmy owl in the wild (few have, as this species is rapidly diminishing in Southern Arizona due to habitat loss). But we know we are in prime pygmy owl habitat — the parcel we are inventorying, 40 acres or so, is undisturbed and thick By Jennifer Patton and Ben Wilder with ironwood and saguaro — key habitat for the bird. It could be a Photography by Ed Flores (except where noted) pygmy owl. With the aid of a game camera and several visits back to the site, the mystery bird revealed itself as a ladder-backed wood- pecker. A year later, while doing research for this article, we realize that the site we were on is right in the middle of the 1990s battleground of the pygmy owl versus development. At that time, roughly 20 owls made their home in Northwest Tucson. Today — none. Another victory for development. Another loss for diversity. TucsonLifestyle.com April 2020 / TUCSON LIFESTYLE 73 What is Species Loss? Extinction is the disappearance of a species from the planet. The ivory billed woodpecker, the western black rhino and the passenger pigeon are well-known examples of animal species that were driven to extinc- tion. In Southern Arizona, the jaguar and ocelot, both endangered species, have headlined recent news stories, as shrinking habitat and loss of connectivity threaten to extirpate these species from Arizona, and heighten the eventual likelihood of their extinction. These majestic cats capture our attention more than numerous other species in our region facing similar fates, includ- ing six species of chub fish (Sonoran, Gila, bonytail, Yaqui, humpback, Virgin River), desert pupfish, the Sonora tiger salamander, the Chiricahua leopard frog, and the south- western willow flycatcher. Gaining even less coverage than amphibians are hundreds of insect and plant species disappearing before many of us have ever noticed them. Extirpation is extinction on a local scale. A species once common in an area is no longer found there, although populations still exist in other areas. The pygmy owl is an example of local extinction. Once common in Southern Arizona, and recently (1990s) in Northwest Tucson, the owl is now found only in Mexico. When the desert is bladed for development, the animals living there must find somewhere else to go, and as the human footprint increases, there is more frequently becoming no “other place.” In addition to the loss of local population, the remaining species as a whole suffers, as there is less genetic diversity and less resil- ience to further loss in numbers. Extinction follows on the heels of extirpation. Cactus wrens, phainopepla, black- throated sparrow, black-tailed gnatcatcher, flicker — once common birds in Tucson — are seeing declines from 30 to 80 percent since the 1960s. Even the verdin, a small energetic bird that is a mainstay of urban areas, is declining. The National Audubon Society attributes this to the loss of habitat and insufficient native vegetation, as well as the corresponding drop in insects that the birds depend on for food. The Main Culprits Species loss is typically due to a conflu- ence of factors. Shrinking and splintered habitat, water depletion, invasive species, pollution, overhunting – each is like an axe blow to the trunk of the biome. Enough blows, and eventually the tree is felled. ”For many species there is more than one threat,” observes Randy Serraglio, Southwest Conservation Advocate with 74 TUCSON LIFESTYLE / April 2020 TucsonLifestyle.com “It’s when you pile on one threat and another and another, and a species habitat gets fragmented into increasingly smaller pieces. — Randy Serraglio the Center for Biological Diversity. “It’s more of the planet into our service. At some when you pile on one threat and another and point, unless we have sci-fi type technology another, and a species habitat gets fragment- breakthroughs, we will have to command ed into increasingly smaller pieces. Then the entire planet to service our collective this little population winks out, and that hunger and wants. Imagine a planet with us, little population winks out, and all you’ve our pets, our domestic livestock, our food got left is one small group and it’s extremely crops, and not much else. vulnerable to single localized events. The At 7.28 million people today, Arizona is resilience is gone and the genetic diver- the 14th largest state by population and the sity suffers. They’re less able to deal with 7th fastest growing state by either percent or stresses. It’s a scientific domino effect once number. It is estimated that new construction things start getting carved up like that. It’s a devours 10 square miles of desert every year. slippery slope to extinction.” Along with land, humans gulp up water. The current world population is 7.8 billion The year-round flow of the Santa Cruz people, increasing by roughly 83 million River, once flanked by cottonwoods and people each year (227,000 people per day). willow, dried up by the late 1800s. As Every person born demands a chunk of the groundwater pumping increases to keep up planet to supply it with food, water, space, with human demand, the water table drops and an ever-improving standard of living. — falling several hundred feet in the last 50 The demands tax the planet’s resources and years. Humans deepen wells and pump in stress the other species with which we share water in response. Plants and animals can- the planet. not. Instead, they take up residence in more Human expansion leading to extinction is favorable habitat or disappear. not a new problem. With each technological The desert bighorn sheep, with herds revolution the human population expands. once ranging throughout the Southwest, Technology may reduce our per capita eco- is emblematic of the struggle that species footprint, but it also enables us to press ever face with increasing human population. Left: Randy Serraglio, Southwest Conservation Advocate with the Center for Biological Diversity Above: The jaguar known as “El Jefe” (The Boss or Chief), who has been spotted numerous times in Southeastern Arizona. Photo courtesy of Conservation CATalyst/Center for Biological Diversity Right: Desert Bighorn Sheep, a species that has been reintroduced in our region. TucsonLifestyle.com April 2020 / TUCSON LIFESTYLE 75 Bighorns historically roamed between southern-facing slopes, or the expanses of mountain ranges, trekking through the Santa wildflowers after sufficient fall rains. We are Catalina, Tortolita, Rincon, and Tucson in awe of the resilience of the trees, shrubs, Mountains. They move to find mates, water, and cacti that flourish on only 12 inches of food and to avoid predation. Genetic mixing rainfall per year, and we enjoy in the intoxi- between smaller populations makes for a cating fragrance of creosote and bursage healthy gene pool. But as human population after a monsoon rain. Why is it then, that increases, areas of suitable habitat become people eradicate the desert plants that flour- Plant Migration smaller and more fragmented. Roadways, ish around their home, replacing them with walls, population centers, the CAP canal, plants from the Mediterranean, Asia, South Can you picture a throng of saguaros, slowly but steadily making even solar fields have created barriers lead- America, and other continents? Our lust for their way south? It is not something ing to isolated populations. exotics comes with a high price to the birds we typically think of, but just like In areas that bighorn remain (often and animals that depend on native plants for humans and wildlife, plants migrate through re-introduction), fire suppression food and cover. in response to climatic factors such degrades habitat. Underbrush thrives, hin- Take a guess at what percentage of vegeta- as shifting water availability and dering movement and blocking sightlines to tion cover in urban Tucson is native. Only 10 temperature. Over the last 2.6 mil- predators. On top of this, humans hike, bike, percent, believe it or not. The showy birds of lion years (the Quaternary geologic and bring their dogs into these remaining paradise and mounds of yellow lantana that period), there have been 50 or so “natural” areas. Without ample room to meet are staples in developed landscapes origi- glaciation cycles in which continental their basic needs, and no way to move to nate in Central and South America.