Sonoran Desert Biome

The Sonoran Desert is a big desert in the southwestern part of North America and people might just think deserts have not a living thing in sight, just hills of sand, well that is not true

The Sonoran Desert is located in North America and covers the southwestern parts of the state of Arizona, southeastern parts of the state of California in the United States and the state of Sonora in Mexico. The Sonoran Desert's location is at latitude 25° to 33° North and longitude 105° to 118° West.

The key to the Sonoran Desert's climate is the amount of rainfall which falls. More rain falls on the Sonoran Desert than any other desert. When it does get rain, the desert is damp, and the air is cool. When it has no rain the desert is really dry and really hot. When the desert is windy, the sand gets picked up and tossed around which creates a sand storm or if the wind is blowing in a certain kind of way, it creates a whirlwind or dust devil. These mini-tornados move across the desert floor and they most often occur in hot weather. The desert valley is hot while up in the mountains it is cool and some mountains are even snow covered.

The seasons are like any other. Spring is a time when flowers bloom if the winter and fall had enough rain that year. There is summer and in the summer it rains the most and that helps summer flowers grow. Then fall comes with a cooler breeze, which lets the deserts summer heat wear away. Winter brings snow to the mountains and cold air to the desert valley.

Precipitation in the desert is probably less then any other North American state, but it is still a lot for a desert. The Sonoran Desert receives 10 or less inches a year; the eastern part of the Sonora desert, in Baja California, receives 10-12 inches because Baja is by the ocean. The ocean storms brew up more often producing more rain, while the western part of the desert only gets about 2 inches and in the mountains they receive 25 inches.

The geography in the Sonoran desert is quite interesting. The Sonoran Desert is located in two states, Arizona and California, and two countries, Mexico and United States. The rivers that flow through the desert are the Colorado River and the Gila River. The Salton Sea, the Gulf of California and the Pacific Ocean are bodies of water next to the Sonoran desert. The mountains in the Sonoran Desert are Mount Kofa and Mount Catalina; Mount Catalina receives most of the snow.

The Sonoran Desert is a hot place to be. It is sandy with a lot of cactuses, but there are forests on the mountains and it is a lot cooler in the forests. The Indians that lived at the edge of the desert carved designs into the walls or rocks. The plants in the Sonoran desert are very interesting, such as fairy duster, jimson weed (poisonous), tumble weed, night blooming cereus, devils claw, ghost flower, hedgehog cactus and showy four o clock. There are some other plants with out really interesting names: The desert Christmas cactus, prickly pear cactus, desert willow, western wildflower, cave primrose and desert lupine. These desert plants adapt to their climate by seeking coolness. Their roots collect water when it rains. The saguaro cactus has shallow root systems allowing the cactus to store up to 160 liters of rainwater allowing it to live for weeks at a time without water. The other adaptations of the desert plants are that they live in the mountains where shade and coolness is found.

The Sonoran Desert animals fit in to the environment perfectly. Some of the animals in the desert are the Mexican gray wolf (el lobo), the mountain lion (cougar or puma), the great horned owl (Bubo virinus), the golden eagle (Aquila chrysaetos) and the rattlesnake. The Sonoran desert is also the home to the Mexican jumping beans. Mexican jumping beans are fruits of a shrub. The movement of the moth larva in the bean makes them jump. The adaptations of the desert animals to the desert home are quit simple. The animals or reptiles can find little hideouts were the sun cannot get to them. Other animals live in the mountains were coolness and shade is found with green forests but the animals have another talent. They sleep in the daytime and the heat does not bother them. Most of the animals are nocturnal, which means they hunt at night when no heat of the day is found.

The Sonoran Desert is changed. We humans have been turning the land from the desert into tourist attractions. These parks have spread for miles taking up the land that belongs to the wild life. Then these creatures are pushed out of their natural habitat. Ranches have also been taking up the desert land and with our livestock. People plant crops and some of the seeds have been picked up by the wind or have been picked up by a bird and the seeds start to grow were they land. This cycle begins again and after awhile the desert starts to have plants that do not belong in the desert.

The Sonoran Desert is a wonderful place but you would never want to be stranded there. The desert has wonderful plants and animals and really beautiful sunsets that fade away on the deserts horizon.

By Elora P. 2003


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The Sonoran Desert is one of North America's most interesting deserts, with more plant and animal types than any other desert in the world. It is the wettest and the warmest desert on the North American continent. The Sonoran Desert is located in the southwestern United States and northern Mexico. In the United States it reaches from southeastern California to the western two-thirds of southern Arizona. In Mexico it includes much of the state of Sonora and the eastern shore of Baja California. It covers an area of approximately 120,000 square miles. There are some mountainous areas where frost occurs, but most of the desert is frost-free. The Colorado, Yaqui, Salt, Verde and Gila Rivers pass through this desert.

The boundaries of the Sonoran Desert are determined by the plants and animals that live in the regions. The Arizona Upland region is located in south-central Arizona and northern Sonora. It has more mountain ranges than other areas of the Sonoran Desert and is the highest and coldest region. The valleys are very narrow. Saguaro cacti are found everywhere except on the valley floors. It is the only region of the Sonoran Desert that experiences frequent hard frosts. Succulent cacti, drought resistant and thorny shrubs are common. On mountainous slopes towards the north, these plants mix with chaparral type vegetation of dense thickets and fire adapted plants

The Lower Colorado Valley is the largest, hottest and driest region of the desert, and is known for its beautiful wildflowers displays. Drought deciduous trees and shrubs are common here. Many are very thorny to discourage browsers. Toward the south the Sonoran Desert gradually merges into the Tropical Dry Thorn Forest of southern Sonora and Sinaloa.

The Sonoran Desert on the Baja peninsula is also known as the Vizcaino desert. Off-shore islands located in the Gulf of California are also part of the Sonoran Desert. The summers aren't quite as hot as the rest of the Sonoran Desert. A high mountain range shields the desert from Pacific storms and accounts for the small amount of rain that falls in the winter. Moisture and fog from the Gulf of California can be considerable, allowing epiphytes to grow on the desert plants. Many different species of succulents like agaves and yuccas grow here.

The Sonoran Desert is known for its beauty and for the amazing cacti and succulents. Some 2,500 plant species grow in the harsh conditions of the Sonoran Desert. More than 160 plant species depend on other plants, like the nitrogen fixing desert ironwood, mesquite, and palo verde trees, to germinate and grow into mature plants. These trees provide plants and animals with a habitat, food and shelter necessary for their survival. Found on the Sonoran coastal plain region, the desert ironwood is the oldest desert tree. The ocotillo has adapted to the severe climate by remaining leafless during the coldest or driest months. They grow new leaves with every rainfall, only to drop them a few weeks after the rainy spell is over. During severe drought, they even drop some of their branches. The most recognizable cactus in the Sonoran Desert is the saguaro cactus. The chain fruit cholla and teddybear chollas, pipe organ, barrel cactus, and jojoba are some other cacti found here.

Between late February and mid April beautiful carpets of annuals like poppies, lupines and owl clover cover the desert floor. These flowers depend on rainfall and this display of flowers occurs only about once in a decade. Locally a good bloom can occur every three years or so. Winters need to come earlier and be wetter than normal. Seeds of summer poppy and devil's claw germinate soon after the first rain and begin flowering only 3 weeks later. Chinchweed has adapted well to all conditions, and ranges from New Mexico into the central Mojave desert.

Herbaceous perennials and shrubs like penstemon, brittlebush, and fairy duster are less sensitive to the timing of rainfall and are more dependable bloomers than the annuals. These plants grow in small patches and don't carpet the ground with color like the annuals do however. Most herbaceous plants flower opportunistically with enough rain, and sometimes more than once. The desert zinnia will flower in both rainy seasons. Ocotillo will grow and shed its leaves three weeks later after every rain.

The Sonoran Desert, like many other deserts, was considered by people in the past to be a wasteland. Now more and more people are attracted to, and moving into the Sonoran Desert. They come to enjoy the large open spaces the desert can give them, to camp and experience the desert in their all-terrain vehicles. Unfortunately, the lifestyles of people, and the needs of wild life are often conflicting. Urbanization is spreading further into the desert every year around Tucson, Arizona. Roads bisect territories, and many animals become road-kill as they attempt to cross. Many species won't cross roads and become isolated in smaller and smaller pockets. This reduces their ability to find mates and reproduce, resulting in the extinction of that species in that particular area of the desert.

Large parts of the Sonoran Desert are still intact due to careful planning and conservation. The Coalition for Sonoran Desert Protection was responsible for getting The Ironwood Forest National Monument designated on June 9, 2000. Located northwest of Tucson this 129,000 acre area contains large stands of ironwood trees and an amazing diversity of birds and animals.

Many areas are already managed by the federal government. Organ Pipe Cactus National Monument is run by the National Park Services, Cabeza Prieta National Wildlife Refuge by the U.S. Fish and Wildlife Service, and the Barry M. Goldwater Air Force Range by the Department of Defense. All together these parks cover more than three million acres west of Tucson, Arizona. The National Parks Conservation Association proposes the establishment of a Sonoran Desert National Park and Preserve. Legislation to authorize a study of management options for the parks is pending in the US Senate.


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