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A traveler crossing overland from Los Angeles to Big Bend National Park in West Texas encounters three of North America's four great deserts, each ecologically distinct and strikingly beautiful. The Mojave of southeastern California and southern Nevada is the most arid of them (Death Valley is tucked in its northeast corner), with a stark landscape sparsely populated by creosote bushes and, at higher elevations, Joshua-tree forests. The Sonoran of southern Arizona and the southeastern tip of California has the longest species list, including fan palms, saguaro cacti, palo verde, and mesquite. The Chihuahuan, reaching up from Mexico to cover portions of southern New Mexico and West Texas, is bisected by the Rio Grande and dominated by yucca and lechugilla (an agave species) growing on mesas and limestone hills. Within this region are hundreds of "sky islands"--mountaintop habitats isolated from one another and remarkably different in composition, because the dry distances separating them have allowed their biotic communities to evolve in distinct ways. Most of these aeries are found near the intersection of Arizona, New Mexico, and Mexico. Here, 2000-plus plant species thrive, nearly 10 percent of all the species found in the United States. The Southwest Deserts also support bighorn sheep, desert tortoises, collared peccaries, roadrunners, gila monsters, kit foxes, bobcats, and kangaroo rats. Yet many animals are endangered by the region's dominant species, Homo sapiens. At the turn of the century, droves of fortune-seekers were lured here by promises of abundant, easily tapped natural resources. After World War II, retirees came to the Sunbelt en masse, searching for dry, healthful living in such artificial, air-conditioned oases as Palm Springs and Phoenix. Today thousands still migrate annually to the deserts to work in tourism or high-tech, or to speculate in real estate. These multitudes have scraped, poisoned, trampled, gouged out, paved over, and dewatered the ecosystem. Even the region's once-famed vistas have been obscured by air pollution from cars, copper smelters, and coal-fired power plants. In this torrid zone, every drop of water is essential to preserving life, yet 90 percent of all riparian habitat in the deserts has been wiped out or severely degraded by overgrazing, mining, heavy logging, water developments, or urban sprawl. Watersheds have been denuded and groundwater reserves sucked up. The Colorado and the Rio Grande, along with their tributaries, often cannot supply enough water to satisfy the thirsts of both large-scale agriculture and booming urban populations. Meanwhile, industrial solvents and agricultural chemicals leach into remaining groundwater tables and river valleys. Along the Mexico-U.S. border, where many U.S. industries have fled in search of low-wage labor (and lax enforcement of environmental laws), toxic wastes and untreated sewage flow freely into streams. To restore the Southwest Deserts Ecoregion to its former glory, the Sierra Club has championed passage of the 1994 California Desert Protection Act, which established three new national parks (Mojave, Death Valley, and Joshua Tree) and designate 4 million acres of wilderness. Activists are also working to achieve full funding and enforcement of the Clean Water Act, educate citizens on how to restore degraded streams, designate wild-and-scenic rivers (in Arizona, activists have identified sections of the Verde, Salt, Gila, San Pedro, and Bill Williams rivers as worthy of such status), and pass state laws preventing ground-water misuse. The Sierra Club has joined with other conservation groups in a effort to designate portions of eight mountain ranges in Arizona's Coronado National Forest as biodiversity conservation areas. These and other efforts will continue until the region is once again hospitable to the endangered desert tortoise and Sonoran pronghorn, and until the long-exiled grizzly and Mexican gray wolf are finally welcomed home. Recommended Reading Contacts Sierra Club Southwest Office
Photo courtesy Philip Greenspun. Up to Top |
