Introduction

Man generally considers these arid regions bleak and lifeless and seeks greener places to live. The Spanish explorer De Anza, traveling across the southern part of what is now California, named the region of his ordeal, “The Land of the Dead.” Scores of grim tales of death and bare survival characterize the history of the California Desert. Yet, even as the sprawling Los Angeles and San Diego metropolitan areas loom on its western edge, there are growing numbers of people who find behind the region’s forbidding aspect a delightful and surprising diversity of natural forms and processes. Many have come to feel an affection for the Desert which is, in the words of one writer, “born of a face perceived, but never fully seen.”

Within the area we know as the California Desert, scientists recognize three deserts: the Mojave, the Sonoran, and a small portion of the Great Basin. Subtropical high pressure belts, the “rainshadow” effect of the coastal mountain ranges, and other topographical features create the conditions by which some geographers define a desert: an area in which evaporation and transpiration exceed the mean annual precipitation.

The California deserts were cooler and moister places in the past. Prior to the end of the last Ice Age, Joshua trees, pinyon pines, sagebrush, and junipers extended across broader expanses than they do today. A subsequent drying trend caused these plant communities to retreat to higher elevations, leaving small enclaves of white fir forests on mountaintops and species like the creosote bush to dominate the lowlands. This trend toward increasing dryness is evident in rainfall records kept since the last century. Today, parts of the Sonora Desert receive less water than any other place in the United States. In addition to aridity, extreme temperatures are a trait of the Desert. The lack of insulating humidity causes wide fluctuations in daily seasonal temperatures varying from 14°F at Deep Springs Valley in January to nearly 117°F at Death Valley in July.

This harsh climate imposes several constraints on natural processes. Desert soils, formed during the humid past, are now often protected against erosional forces only by natural soil crusts, called “desert pavement,” and what little stability that the sparse desert vegetative cover provides. Any surface disturbance of these features leaves the thin desert soil exposed to severe climatic factors.

In the older deserts of the world, wind and water have scoured features of the landscape into flat, low-relief surfaces. In the California Desert, a variety of land forms, including valleys, bajadas, pediments, alluvial fans, rough-hewn mountain ranges, washes, sand dunes, and dry lakebeds, testify to its relative youth as a desert. These land forms mix with varying soil conditions and climatic variations to form a number of ecosystems, in which desert plant and animal life face formidable challenges from both the human and natural environment in their fight for survival.

Desert organisms face a tough task to maintain water balance. Most plants are annuals which avoid the problem of aridity by remaining in the form of seeds until rains bring them to life. During their short span of growth, they present the stunning displays of wildflowers which are well known in some parts of the California Desert.

Desert perennials often use novel physiological and anatomical adaptations to endure this hostile environment. Some plants have “dual” root systems, with wide lateral roots to catch surface water and deep “tap” roots to search out underground moisture. Short-rooted succulents store water in their stems and ration it during dry spells. Plants like the drought-deciduous ocotillo shed their leaves entirely during these periods to reduce water loss through evaporation. Some agave and yucca plants are able to reduce water losses by taking in carbon dioxide needed for photosynthesis at night.

Some desert animals also display these special structural adaptations. The desert tortoise is able to store water in sacs under its shell. Some desert arthropods can take water directly from the air when the relative humidity is over 80 percent. More often, however, the desert animal’s adaptation is behavioral; it limits activity to the coolness of night, dawn, or dusk. Much desert activity occurs around seeps, springs, and other surface-water sources which, although rare, are extremely important to the carefully balanced natural ecosystems.

An understanding of the relationship between natural processes and landscape cannot be complete without a recognition of the human presence. Man is not an alien in the environment. His structures and activities change and become a part of the system. It is inevitable that, as population and economic activity expand, the natural setting and associated life forms will change. In the California Desert a pattern of human uses has evolved from a multitude of single-purpose venture s which reflect western history and serve present needs.

The earliest inhabitants of the California Desert wrought changes in the land which are still visible in many areas. These Native Americans, prior to European contact in the mid-16th century, hunted and foraged for food, set down permanent and seasonal village sites, mined and quarried for common and exotic stones, flood irrigated land for agriculture, and traded goods through an elaborate network of foot trails. Their awe and respect for natural features and processes formed the basis for religious practices. The native system of foot trails was of great value to the Spanish , who saw the Desert as little more than a daunting obstacle over which they had to travel between their settlements in Mexico and coastal California. After acquisition of the area by the United States in the mid-19th century, land-use intensity continually increased.

Initial forays through the area were made by explorers, soldiers, and Mormon settlers. Then came a growing stream of emigrants bound for coastal California, protected by military forts and supplied by outposts along the route. Washington treaty makers and railroad surveyors arrived next, and some remained in the region. In 1856, one government surveyor staunchly defended his activities in the region against the cries of those who claimed the place was “not worth a red cent.” Fanning out from the trail outposts, miners began creating colorful desert settlements that went though boom-bust cycles until the end of the century. By 1868, with the subduing of the native population, most of the major modern California Desert land uses had become entrenched in some form: livestock grazing, mining, military bases, major transportation arteries, and the growth of permanent settlements. Railroad facilities and mining operations, mainly those for precious metals but also for the celebrated borax trade, had substantial, although often ephemeral, impacts. Ranchers grazed their livestock across a wide expanse of the Desert, at one time almost its entire western portion.

After the turn of the century the dominance of these activities challenged when the construction of a canal from the Colorado River transformed “The Land of the Dead” into the Imperial Valley, now one of the most productive agricultural spots in the world. Anticipating its destiny, the city of Los Angeles brought water across more than 200 miles of the Desert from the Owens Valley, presaging a number of large water projects.

Between two world wars, the freewheeling days of the prospector waned as corporate entities developed large operations. The reign of the railroads reached a national and local zenith and then faltered as roads were laid across the Desert. Highway settlements and resorts sprang up to serve automobile travelers, many of whom had been inspired by authors who had described the Desert as a beautiful, delicate place. Foremost among these authors was John C. Van Dyke, who wrote in the preface to his 1901 book, The Desert: “The desert has gone a-begging for a word of praise these many years. It never had a sacred poet; it has in me only a lover.” By the 1930's, this new sentiment had evolved into legislation creating the Desert’s three large parks: Anza- Borrego State Park and Joshua Tree and Death Valley National Monuments. More water projects, notably the Colorado River Aqueduct, brought pumping stations and other support facilities, and the first appearance of longhigh- voltage power transmission lines. After and absence of many years, the military was lured back to the California Desert sun, clear air, and sparsely settled landscape because of the country’s new interest in flying. As they did elsewhere in the Nation, military concerns dramatically usurped all other activities in the California Desert during World War II. The desert lands, however experienced perhaps more impacts from military operations than anywhere else in the country. Preparing for North African tank warfare, General Patton’s troops ranged across vast expanses of the landscape. The Army Air Corps and the Navy withdrew large tracts of land for training and the testing of a rapidly evolving weapons technology.

The formation of the modern California Desert character began immediately following the war. In 1946, livestock grazing became more regulated under the stewardship of the newly formed Bureau of Land Management. The Bureau also administered such disposal policies as the Small Tract Act of 1938, which allowed private individuals to secure five-acre tracts for a very small fee. Attracted by this opportunity, other land deals, and the boon of such new technology as air conditioning, refugees from coastal California’s urban problems spilled over into the western fringes of the Desert. Residential developments ranged from the closely spaced suburbia of Palm Springs to “jackrabbit homesteads,” shacks measuring 20 feet on each side and dispersed sparsely across hundreds of square miles. The war’s legacy of jeeps and aircooled engines allowed visitors to penetrate even the most remote regions of the Desert, while cheap gas and improved roads made auto touring increasingly popular. Mineral operations increased in size, but not generally in number.

Today, the physical manifestations of these human pressures have become evident across the entire desert landscape: over 100 communities, ranging in type from one-person mining settlements to resorts: large industrial mining operations and thousands of speculative digs; canal-fed agricultural valleys; nine military bases and testing groungs; 1.1 electrical power generating plants; 3,500 miles of high-capacity power transmission lines; 12,000 miles of oil and gas pipelines; over 100 communication sites on ridges and mountaintops; 15,000 miles of paved and maintained roads; and thousands more miles of roads and ways cut solely by motorized vehicles.