North American Deserts is a Level I terrestrial ecoregion of North America designated by the Commission for Environmental Cooperation (CEC) in its North American Environmental Atlas. The North American Deserts include both cold and hot deserts, which supply a variety of climates. Due to this fact, they are often used for agricultural, business, or petroleum purposes. These factors have been taking a toll on the desert climate, organisms, and landscape. These deserts are the Mojave, Sonoran, Chihuahuan and the Great Basin.
List of deserts
Flora and fauna
Plant communities The North American Deserts are home to a variety of plant species. These plants are categorized as either xerophytes, adapted to the arid conditions of the desert, or phreatophytes, which are plants with very deep roots that are dependent on a permanent water supply and survive by tapping groundwater.
These species have come to possess several adaptations that allow them to survive and thrive in these dry and harsh conditions. One of the most common of these species is the barrel cactus (Echinocactus and Ferocactus). This plant was important to Native Americans and served a number of purposes, including use for food and water and creating fish hooks from the spines. Another common species is the Shin Digger (Agave lechuguilla).
With its shallow roots, it is able to take in a large quantity of water and store it in its pedals for extended periods of time. The Ocotillo (Fouquieria splendens) is another plant frequently found in this area, which is a very unusually shaped plant. Because of this, it is often referred to as a "vine cactus." This plant has an adaptive ability to photosynthesize during very dry conditions and gather large quantities of water when it is available.Royo, A. R. "Ocotillo." Fouquieria Splendens (DesertUSA). DesertUSA, n.d. Web. 24 April 2013. <http://www.desertusa.com/nov96/du_ocotillo.html>. The Great Basin is also home to the oldest species in the world, the bristlecone pine (Pinus longaeva). Its needles allow it to retain water and use very little of it during its lifetime. It is able to grow on exposed rocky surfaces in higher elevations about forested areas. With these advantages come some drawbacks, including its very slow growth rate, which leaves it vulnerable to being out-competed by faster growing trees.http://www.nps.gov (2013, February 14). Retrieved from National Park Service website: https://www.nps.gov/grba/learn/nature/treesandshrubs.htm
Animal species There are a variety of mammals that define the North American Deserts such as the bighorn sheep, mule deer, white-tailed deer, ground squirrel, coyote, prairie dog, cottontail rabbit, desert packrat, and mountain lion. There are a number of birds and reptiles that thrive in these ecosystems as well. The cactus wren, Gambel's quail, burrowing owl, red-tailed hawk, hummingbird, desert tortoise, and vulture to name a few.
An example of a keystone species in the North American deserts would be the coyote or mountain lion. These two predators can control the population and distribution of a large number of prey species. A single mountain lion can roam an area of hundreds of kilometers, in which deer, rabbits, and bird species are partly controlled by a predator of this caliber. They will change the feeding behavior or where they decide to nest or burrow is largely a reaction to the mountain lions activity. Another example, such as the hummingbird, new plants or animals could also come into the habitat and push out native species. In the Sonoran Desert, the hummingbird pollinates many native species of cactus and other plants. The hummingbirds in this region, such as the Costa's hummingbird, have evolved to have very long beaks and tongues that wrap around the skull in order to reach the nectar for that sweet sugar staple.
Endangered species The giant kangaroo rat is an unusual rodent. The Dipodomys ingens can grow up to 34.7 centimeters in length and have a tail of up to 19.8 centimeters long. They can weigh up to 180 grams. It is mainly found in the San Joaquin Valley in California. The giant kangaroo rat forages for food from sunset to sunrise. Its diet consists mainly of seeds, that are sun dried and some greenery. They store food in their cheeks until they bring it back to their burrow systems, where they store food that could last them up to 2 years of drought. The giant kangaroo rats develop rather quickly. Depending on the environmental conditions, they can reproduce after about 5 months. Their litter size varies but averages about 3.75 offspring. These rodents are rather resilient when it comes to surviving under natural conditions, such as drought and low plant productivity. However, when the human factor is introduced, they have a much less successful survival rate. Aqueducts and other water projects started crisscrossing the giant kangaroo rat habitat. Agriculture moved in because of the new water routes and suddenly the habitat of many species became agricultural land. Kangaroo rats became a pest for farmers and rodenticide-treated grain became common practice which took out another chunk of their population.
Nichol's Turk's head cactus (Echinocactus horizonthalonius var. nicholii) is one of multiple species of Echinocactus horizonthalonius. The Nichol's Turk's head cactus ranges from blue-green to yellow-green. It tends to be around 46 centimeters tall and has about a 20 centimeter diameter. It has 8 ribs that are lined with spines. The cactus blooms from April to May with a purple flower and white, hairy fruit.U.S. Fish and Wildlife Service. 1998. Threatened and Endangered Species of Arizona. Arizona Ecological Service Field Office. Phoenix, AZ. pp. 21-22. Like many cacti, it is rather slow growing at a rate of just 2 inches in 10 years, due to minimal nutrient input.Arizona Game and Fish Department. 1994. Echinocactus horizonthalonius var. nicholii. Unpublished abstract compiled and edited by the Heritage Data Management System, Arizona Game and Fish Department, Phoenix, AZ. Albuquerque, New Mexico. Its habitat is located mainly in the Vekol and Waterman Mountains in Arizona and it has a population in the Sierra del Viejo Mountains of northwestern Sonora.U.S. Fish and Wildlife Service. 1986. Nichol Turk' s Head Cactus (Echinocactus horizonthalonius var. nicholii) Recovery Plan. Albuquerque, New Mexico. The cactus is particularly fond of Horquilla limestone outcrops.McIntosh, M. E., Boyd, A. E., Jenkins, P. D., & McDade, L. A. (2011, September 1). GROWTH AND MORTALITY IN THE ENDANGERED NICHOL'S TURK'S HEAD CACTUS ECHINOCACTUS HORIZONTHALONIUS VAR. NICHOLII (CACTACEAE) IN SOUTHEASTERN ARIZONA, 1995-2008. Southwestern Naturalist, 56(3), 333-340. Retrieved March 9, 2013, from Academic Search Premier. The biggest threats to these cacti are habitat loss to new development, vehicle/off-roading damage, mining, and human collection. Among other threats, erosion from foot traffic from drug and human trafficking in the area.
Topography, geology, and soils The Great Basin Desert is the only Cold desert, bordered by the Rocky Mountain range to the east, and the Sierra Nevada – Cascade to the west. The northernmost part of the desert lies above sea level, and due to high summer temperatures, not all of the fallen precipitation is fully absorbed into the soil, resulting in a high sodium concentration.Smith, S.D, Monson, R.K, Anderson, J.E. Adaptations of Desert Organisms: Physiological Ecology of North American Desert Plains. (1997) In other areas, mountain erosion has caused deep soils of fine particles, which allows for standing lakes.
The Mojave lies between the Sonoran (south) and the Great Basin (north). Here, soil is shallow, rocky, and dry. The average elevation is between above sea level. The Mojave has several mountain range boundaries, the Garlock and the San Andres. They are made up of the two largest faults in the state of California.
The Sonoran is referred to as the Base and Range geologic province. Here, the Mogollon rim exists of sandstone and limestone piled over millions of years. The basin and valley were made from volcanic eruption 40 million years ago, and the underlying rock is made primarily of cretaceous (aged granites).
The Chihuahuan desert is made up of calcareous soils that have a high pH and calcium concentration. The soil is thin, sandy, and gravel like, and rests atop deep layers of limestone. Higher elevations allow water to sink deeper into soils that are made of finer particles, and deep sedimentary fans exist. Limestone beds show that this desert was at one point fully submerged beneath the sea. This desert features elevations ranging from above sea level, to below.
Hydrology There are common patterns of hydrological cycles throughout the North American Deserts, but specifics of times and source of water range. All four deserts rely on rivers, precipitation, and underground aquifers to replenish their water supply."North American Deserts." DesertUSA. N.p., n.d. Web. 11 March 2013. <http://www.desertusa.com/glossary.html>. The water in the North American desert is mainly freshwater. There is an ephemeral flow of underground water during the wet seasons that slows during each sub-desert's dry season.Stamos, Christina. "Mojave Water Studies." USGS. California Water Science Center, 23 February 2012. Web. 9 March 2013. <https://ca.water.usgs.gov/mojave/>. Oases form in all four deserts when the groundwater reaches the surface and pools in the hollows of the desert basins."The Chihuahuan Desert." Digital Desert Library. New Mexico State University, n.d. Web. 14 March 2013. <>. Being surrounded by mountains provides a rain shadow effect that contributes to the dry climate and creates the desert ecosystem.Hatheway, Becca. "Rain Shadow." Windows to the Universe. N.p., 17 September 2008. Web. 13 March 2013. <http://www.windows2universe.org/earth/Atmosphere/precipitation/rain_shadow.html>. All four deserts experience times of drought and times of intense precipitation.Chambers, Jeanne C., and Colo Collins. "Chapter 1: Introduction and Overview." Geomorphology, hydrology, and ecology of Great Basin meadow complexes implications for management and restoration. Fort Collins, CO: U.S. Dept. of Agriculture, Forest Service, Rocky Mountain Research Station, 2011. 2-10. Print. The Colorado River flows through the Mojave, Great Basin, and Sonoran desert.
But, differences in seasonal rain create the differing hydrological cycles. The Great Basin receives most its rainfall in the winter. This leads to creation of playa lakes in the spring, as the snowfall melts and flows down surrounding mountains."Playa Lakes | Wetlands | US EPA." EPA. US Environmental Protection Agency, 6 March 2012. Web. 10 March 2013. <https://www.epa.gov/wetlands/playa-lakes>. The Sonoran Desert has a bimodal precipitation pattern that includes winter storms and summer monsoons, which help sustain flora."Sonoran Desert." Arizona-Sonora Desert Museum. N.p., n.d. Web. 9 March 2013. <http://www.desertmuseum.org/desert/sonora.php>. The Chihuahuan Desert relies primarily on its intense summer monsoon for water. During the summer is when the area sees the accumulation of playa lakes. They may all have similar characteristics, but the difference in location and evaluation attribute to the diversity of their hydrological sources and cycles. Although the Northern American Deserts are characteristically dry, they still contain the water necessary to fuel their ecosystem and sustain the life of humans, animals, and plants alike.
Climate North American deserts can be categorized by climate categories of hot and cold deserts. The cold deserts include the Thompson Okanagan Plateau, Columbian Plateau, Northern and Central Basins, Colorado Plateaus, and the Snake River Plane.