Introduction
Deserts make up close to a fifth of the earths surface, and they occur in areas where the annual rainfall is below 50cm. Most of these deserts, such as the Sahara of North Africa, occur at low altitudes though others occur at relatively lower latitudes and are referred to as cold deserts. However, such deserts are more deficient in life forms and species because of the freezing temperatures limiting plant life. The United States has four significant deserts located in the western part of the country. It collectively covers about 500,000 square miles from Oregons and Nevadas lonesome sagebrush backlands to central Mexicos cactus groves. Their location is attributed to their distances from moisture sources, rain shadow-casting mountains, permanent sub-tropic high-pressure zones, and combinations of the factors above. Each gets lower than 10 inches in annual precipitation. These deserts are the Great Basin, Mojave, Sonoran, and Chihuahuan. Therefore, this paper focuses on the unique features of each of the deserts and comprehensively discusses their geographical composition, including their climates, topography, and flora and fauna.
The Great Basin Desert
The Great Basin Desert is the largest in the United States, and it is the northernmost and highest-elevation of them, all covering about 200,000 square miles. The desert is often freezing, and the precipitation recorded in it is snow due to its location at high altitudes of up to more than 6,000 feet (Puckett 67). This is why, unlike the preconceived perception that deserts are hot, the Great Basin Desert is very cold with equally cold winters (Jones and Luna 98). However, the precipitation varies with latitude seasonally, with temperatures inhibiting the growing season to the summer.
The deserts location stretches between the Sierra Nevada and the Southern Cascades to the West and the Rocky Mountains on the east. To the south, it borders the lower hotter region of the Mojave Desert and Columbia Plateaus bunchgrass steppes and semiarid sagebrush, including the Snake River Plain to the north (Puckett 80). Despite this comprehensive geographical coverage, most of it is in Nevada though specific minutes parts are in Oregon, California, and Utah states (Jones and Luna 99). There is very little rainfall in this region, primarily because of the shield formed by the Sierra Nevada Mountains, which inhibits the Pacific Oceans winds from moisturizing the area.
Additionally, the deserts topography is characterized by basins and mountain ranges hence its name. This arises majorly from its reliefs separation with high mountain crests below intervening bosons that form major drainage to the outlets (Puckett 84). There are also ephemeral lake beds located on the basins floors with specific permanent water sources like the Pyramid and Great Salt lakes (Jones and Luna 89). They are considered the remnants of the numerous and more significant Pleistocene Great Basin lakes.
However, the desert lacks botanical variety though its animal and plant communities define its uniqueness. Shadscale and sagebrush are the most common plants in the desert, with the bristlecone pine considered one of the unique plants to grace the area (Puckett 85). The tree is arguably the oldest known living organism globally, with other trees estimated to have existed in the area for over 5,000 years (Jones and Luna 95). Nonetheless, the big sagebrush dominates the site, so the desert is often referred to as the Sagebrush Sea. There are also saltbushes, greasewoods, salt grasses, and salt-tolerant plants which cover the saline regions. Moreover, it is segued by a black brush realm with its steamways lined by willow and scrawny cottonwood gallery forests. Furthermore, its mountainous areas are covered in non-desert woodlands and forests. Despite the variety presented, the site is still dominated by the gray sagebrush.
The Great Basin Desert is also characterized by vast public lands managed by the Bureau of Land Management (BLM), which serve as get-ways to the deserts adventurous iconic destinations. These include the Bonneville Salt Flats and Nevadas Black Rock Desert (Jones and Luna 96). Moreover, the Great Basin National Park lies within the wetter Snake Range area with lower elevations covering the more delicate wild desert regions (Puckett 85). Additionally, some of the open sources accommodate some known long-distance animal movements such as the Sheldon National Antelope Refuge, pronghorn migration route, and the Hart Mountain National Antelope Refuge. These take place in northwestern, winter ranges, and southeastern Oregon, respectively.
Despite the relatively adverse climatic conditions, the desert still serves as a home to several endangered and threatened species. The threat is brought about by its vast expanses, which render it vulnerable to extinction since the species occupying high peaks cannot interbreed due to isolation (Puckett 85). Moreover, grazing, groundwater pumping, mining, and home and road construction also affect the habitats of these species. These species include the most miniature tern birds, Utah prairie dogs, desert dace, Lahontan cutthroat trout, and White River spine dace fish (Jones and Luna 99). The Ute ladys tresses and soda Ville milkvetch also fall in this category. These plants have to be protected as required lest the desert loses such rich organisms.
The Mojave Desert
The desert is essentially the northernmost of the four, and it is more of a transition land between Sonoran and the Great Basin. It covers about 54,000 square miles making it the most minor, and this spans across Nevada, California, and Arizona (Klinger et al. 10). The desert has extremely high elevations ranging from a low point of 282 feet at Death Valley to a high of 11,049 feet at Telescope Peak (Clair and Hoines 197). These high elevations get extremely cold at night. However, at the Death Valley, the low points are always boiling. This area is considered the hottest in the United States, with a temperature high of 134 degrees Fahrenheit and an average rainfall of below 2 inches. However, the precipitation generally is similar to that of the Great Basin Desert, with most of it coming during winter, though, in the Mojave Desert, it falls as rain (Clair and Hoines 199). Moreover, it is characterized by ephemeral Mojave wildflowers springtime blooms which make its climate rather unique.
Additionally, the desert is yielded by the creosote bush, which is a defining shrub for most hot deserts in America. However, Mojaves trademark plant is the Joshua tree which maps out its geography (Klinger et al. 11). The outsized yucca flourishes in this region, hitting its developmental peak on its peaks and the bajadas and foothills middle slopes. The land is also covered in grasses, though sparsely, with the creosote bushes complementing these grasses (Clair and Hoines 200). Additionally, the desert is home to various animals such as rabbits, scorpions, lizards, the Mojave ground squirrel, pronghorns, the kangaroo rat, and snakes.
The soil types in the desert are volcanic, especially the parts in the state of California. However, the particle sizes decrease as the topography goes down, where there is also relatively low alkalinity. This forms a good breeding ground for plants around the erosional gradient. However, alluvial fan and pediment soil up the deserts slope, with the flora being mostly succulents (Klinger et al. 12). Moving down the gradient, the area is encompassed the lower and upper bajada and into the saline and playa, ending up at the river (Clair and Hoines 230). The lower bajada mostly has evergreen perennials though some parts of the upper bajada exhibit the same. Nonetheless, most plants are adapted to buried bulbs, waxy leaves, deep taproots, ephemerals, spines, and photosynthetic stems due to harsh conditions.
Further, the desert is defined by xeric conditions created by the multiple mountain ranges surrounding the region. As a result, the contents lead to seasonal saline lakes, valleys, salt pans, and endorheic basins, especially when the precipitation rate is significant. However, most of these are part of the Great Basin and the Basin and Range province, which are geologic areas of crustal thinning, leading to the opening of various valleys (Clair and Hoines 233). Nonetheless, most of the valleys drain internally such that not all the precipitation that falls within the region flows to the ocean. It is also essential to note that a section of the deserts domain is in a different geographical field known as the Colorado Plateau (Klinger et al. 14). This is the part around the Virgin River George and Colorado River, which is towards the East.
Further still, the desert is among the most popular tourist destination locations in the United States. This is brought about primarily by Las Vegass gambling destination. Moreover, it has particular scenic sites like the Mojave National Preserve, Death Valley National Park, and the Joshua Tree National Park (Klinger et al. 15). Additionally, it houses three California State Parks and lakes, Havasu, Mead, and Mohave also attract tourists, primarily due to their provision for water sports recreational activities (Clair and Hoines 240). Furthermore, various natural features in the Calico Mountains, such as the Calico Ghost Town, also serve as essential attractions. The desert is indeed full of scenic and attractive sites, and its location accords it the tourists traffic that it deserves.
The Sonoran Desert
The Sonoran Desert occupies about 100,000 square miles, and over two-thirds of this is located along the Mexico-U.S. line covering the State of Sonora and Baja California. It mainly occupies southern Arizona in the U.S (Bradley and Colodner 110). The Sonoran Desert has sub deserts within it, including the Yua Desert, Yuma Desert, Colorado Desert, and the Tonopah Desert. Additionally, rivers Gila and Colorado flow through it complemented by the mountains and broad valleys which get extremely hot in the summer.
Furthermore, the desert is ranked among the worlds excellent deserts because of its scenic and botanical splendor. This plantlife stems from two rainy seasons prevailing in the southern and eastern sectors, winter and summer precipitation (Sosa et al. 65.). It is known chiefly for its saguaro cactus, which grow up to above 60 feet tall with arm-like branches. It is often referred to as the Arboreal Desert based on these cacti (Bradley and Colodner 115). Apart from these, several other species with unique shapes and sizes, such as the mighty cardoon, the Mexican portion, the multi-pillared organ pipe cactus, the wild-armed ocotillo, mention a few. Over 2,000 plant species have been collectively identified in the desert, with each of the physiological vascular plant groupings dominating more than one major biotic communities (Sosa et al. 67). This is why it is considered to have the most significant diversity when it comes to species with relatively fine spatial scales.
To add to that, it is also home to multiple animals, which adds to its species diversity. Researchers have identified over 350 bird species, 100 different reptiles, 20 amphibians, and about 30 fish species within the desert (Sosa et al. 68). Such species include owls, lizards, jackrabbits, snakes, bats, turtles, and sparrows (Bradley and Colodner 117). These species also show tremendous variability in life forms attributed to various factors such as the varied geology, subtropical climate, bimodal precipitation, continental physiography, and wide-ranging topography.
The regions climate is also somewhat unique as it receives frequent low-intensity winter rains and violent summer monsoon thunderstorms. These contradicting climatic conditions are borrowed with the former from the Mohave Desert and the latter from the Chihuahuan Desert (Sosa et al. 72). These distinct patterns support the vast array of flora and fauna, and it is the foundational cause of the species diversity experienced in the region. Annually, precipitation in the area averages 3 to 20 inches depending on the location, with substantial variability in quantity and timing. Nonetheless, the Sonoran is still a hot desert with summer air temperatures exceeding 104 degrees Fahrenheit, which interact with the cool, moist air in the region to produce violent summer monsoon thunderstorms (Bradley and Colodner 120). Still, the surrounding mountains in the area have dense snow cover with valley bottoms free of frost and mild winter temperatures. Nonetheless, the deserts vast vegetation often reradiate the daytime heat overnight into the atmosphere leading to diurnal swings.
As a result of the vast array of species, the desert is a prime tourist attraction site. Moreover, there are various national parks, reserves, monuments, parks, botanical gardens, history museums, desert landscape gardens, and science research institutes that contribute to its vast tourism (Sosa et al. 72). Apart from tourism, it is also a location for illegal migration from Mexico into the United States due to low security levels. Most of this unauthorized entry takes place at night due to the harsh daytime conditions.
The Chihuahuan Desert
The Chihuahuan Desert is the largest in North America, covering about 250,000 square miles. Only about 10% of the desert is in the United States, with the other 90% in Mexico (Hruska 270). The portion that is in the U.S. covers parts of southeast Arizona, southwest Texas, and southern New Mexico. It resembles the Great Basin because it is above 3,500 feet, even though the southern part has tall cacti (Hruska 270). The desert is isolated from the neighboring arid regions by the Sierra Madre Oriental, and the Sierra Madre Occidental mountain ranges to the east and west, respectively.
When it comes to flora and fauna, it is considered the most diverse desert in the Western Hemisphere though it is also one of the most endangered areas in the world. This threat arises from urbanization, overgrazing, invasive exotic species, water diversion and depletion, fire regime changes, and native plants and animals over-collection (Hruska 270). Despite these issues, the deserts eastern boundary is the wealthiest plant evolution center. The vegetation ranges from conifer woodlands and desert shrublands depending on elevations though the creosote bush is the most dominant plant. It also has prickly-pear cactuses, yuccas, grasses, and agaves, contributing to its over 3,500 plant species (Hruska 276). However, about 1,000 of these grow in its Ecoregion (Minckley et al. 457). Moreover, the Chihuahuan Desert has given unique habitats like the gypsum dunes, freshwater habitats, playas, and yucca woodlands, making it very diverse.
Furthermore, the desert houses over 170 reptile and amphibian species, with about 18 of these endemic to its Ecoregion. There are also over 110 fish species in the region, with most of these being endemic. The relic ones are found in the closed basins where the isolated springs lie (Hruska 280). Moreover, the desert supports over 130 mammal species such as the jaguar, grey fox, mule deer, javelin, and pronghorn. Historically, it was among the few regions where the wolves and grizzly bears would be found. It is also home to about 400 bird species, and its grasslands serve as wintering grounds for the birds (Minckley et al. 460). The birds include Bairds sparrow, mountain plover, and the ferruginous hawk.
However, the deserts climate is unique compared to that of the Mojave and Sonoran deserts. This is because it has colder winters and receives a lot of summer rain during monsoon thunderstorms. Therefore, it is characterized by cold, dry winters and hot summers with annual precipitation of about 6 to 20 inches (Hruska 290). However, most of the rain falls in the summer months in the form of monsoonal showers. Its range and basin topography consists of mountain ranges, basins bordered by terraces, and mesas (Minckley et al. 461). The bays provide a suitable location for the drainage of rainwater internally, contributing to the formation of playas. Dune fields made of gypsum sand and quartz are also standard features.
The region has various protected areas which are prime for tourism. These areas include the Buenos Aires National Wildlife Refuge, Apache National Wildlife Refuge, and the Franklin Mountains State Park (Minckley et al. 466). Moreover, the Big Bend National Park is home to over 800,000 acres of the deserts wildlife and plant (Hruska 295). The park offers a vast, spectacular backcountry for exploration from the grand existent canyons and the Chios Mountains. There is also the Rio Grande River which flows through the desert down to the Gulf of Mexico. These features accord the desert the tourism traffic making it ripe for revenue collection for both the Mexican and U.S. governments.
Conclusion
The United States has arguably the most diverse types of deserts. These deserts present unique characteristics ranging from the nature of the climatic conditions, flora and fauna, and even topography. From the preceding, it is clear that the four, the Chihuahuan, Sonoran, the Great Basin, and Mojave, also have similar characteristics. These features mainly arise because of their proximity to each other in the United States. This shows the significance of immediacy when it comes to the geographical study of deserts despite the differences highlighted regarding the hot deserts and cold deserts. Nonetheless, the deserts still serve as important tourist sites and prime locations for research, a sound source of revenue, unlike the contemporary perception of deserts being non-economic features. Therefore, the government needs to continue protecting these sights from any interference to ensure the given flora and fauna within flourish.
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