Life in the Desert Plants and animals adapt to desert habitat s in many ways. Desert plants grow far apart, allowing them to obtain as much water around them as possible. This spacing gives some desert regions a desolate appearance. In some deserts, plants have unique leaves to capture sunlight for photosynthesis , the process plants use to make food. Small pore s in the leaves, called stomata , take in carbon dioxide.
When they open, they also release water vapor. In the desert, all these stomata would quickly dry out a plant. So desert plants typically have tiny, waxy leaves. Cactus es have no leaves at all. They produce food in their green stems. Some desert plants, such as cactuses, have shallow, wide-spreading root system s. The plants soak up water quickly and store it in their cell s.
Saguaro cactuses, which live in the Sonoran Desert of Arizona and northern Mexico, expand like accordions to store water in the cells of their trunks and branches. A large saguaro is a living storage tower that can hold hundreds of liters of water.
Other desert plants have very deep roots. The roots of a mesquite tree, for example, can reach water more than 30 meters feet underground.
Mesquites, saguaros, and many other desert plants also have thorns to protect them from grazing animal s. Many desert plants are annual s, which means they only live for one season.
Their seeds may lie dormant for years during long dry spells. When rain finally comes, the seeds sprout rapidly. Plants grow, bloom, produce new seeds, and die, often in a short span of time. A soaking rain can change a desert into a wonderland of flowers almost overnight. Animals that have adapted to a desert environment are called xerocole s. Xerocoles include species of insects, reptiles, birds, and mammals. Some xerocoles avoid the sun by resting in scarce shade. Many escape the heat in cool burrow s they dig in the ground.
The fennec fox, for example, is native to the Sahara Desert. Fennec fox communities work together to dig large burrows, some as large as 93 square meters 1, square feet. Dew can collect in these burrows, providing the foxes with fresh water. However, fennec foxes have adapted so they do not have to drink water at all: Their kidney s retain enough water from the food they eat.
Most xerocoles are nocturnal. They sleep through the hot days and do their hunting and foraging at night. Deserts that seem desolate during the day are very active in the cool nighttime air. Foxes, coyotes, rats, and rabbits are all nocturnal desert mammals.
Snakes and lizards are familiar desert reptiles. Insects such as moths and flies are abundant in the desert. Most desert birds are restricted to areas near water, such as river banks. However, some birds, such as the roadrunner, have adapted to life in the desert.
The roadrunner, native to the deserts of North America, obtains water from its food. Some xerocoles have bodies that help them handle the heat. Some desert vultures urinate on their own legs, cooling them by evaporation. Many desert animals have developed ingenious ways of getting the water they need. The thorny devil, a lizard that lives in the Australian Outback , has a system of tiny grooves and channels on its body that lead to its mouth.
The lizard catches rain and dew in these grooves and sucks them into its mouth by gulping. Camels are very efficient water users.
The animals do not store water in their humps, as people once believed. The humps store fat. Hydrogen molecule s in the fat combine with inhaled oxygen to form water. During a shortage of food or water, camels draw upon this fat for nutrition and moisture. Dromedary camels, native to the Arabian and Sahara deserts, can lose up to 30 percent of their body weight without harm.
People and the Desert About 1 billion people live in deserts. Many of these people rely on centuries-old customs to make their lives as comfortable as possible Civilization s throughout the Middle East and Maghreb have adapted their clothing to the hot, dry conditions of the Sahara and Arabian deserts.
Clothing is versatile and based on robes made of rectangles of fabric. Long-sleeved, full-length, and often white, these robes shield all but the head and hands from the wind, sand, heat, and cold. White reflects sunlight, and the loose fit allows cooling air to flow across the skin.
These robes of loose cloth can be adjusted folded for length, sleeves, and pockets, depending on the wearer and the climate. A thobe is a full-length, long-sleeved white robe. An abaya is a sleeveless cloak that protects the wearer from dust and heat. A djebba is a short, square pullover shirt worn by men. A kaffiyeh is a rectangular piece of cloth folded loosely around the head to protect the wearer from sun exposure, dust, and sand.
It can be folded and unfolded to cover the mouth, nose, and eyes. Kaffiyehs are secured around the head with a cord called an agal. A turban is similar to a kaffiyeh, but wrapped around the head instead of being secured with an agal.
Turbans are also much longer—up to six meters 20 feet! Desert dwellers have also adapted their shelters for the unique climate. The ancient Anasazi peoples of the southwestern United States and northern Mexico constructed huge apartment complexes in the rocky cliff s of the Sonoran Desert. These cliff dwellings, sometimes dozens of meters off the ground, were constructed with thick, earthen walls that provided insulation.
Although temperatures outside varied greatly from day to night, temperatures inside did not. Tiny, high windows let in only a little light and helped keep out dust and sand. The need to find food and water has led many desert civilizations to become nomadic. Nomadic cultures are those that do not have permanent settlements. In the deserts of the Middle East and Asia, nomadic tent communities continue to flourish. Tent walls are made of thick, sturdy cloth that can keep out sand and dust, but also allow cool breezes to blow through.
Tents can be rolled up and transported on pack animal s usually horses, donkeys, or camels. Nomad s move frequently so their flocks of sheep and goats will have water and grazing land.
Besides animals like camels and goats, a variety of desert vegetation is found in oases and along the shores of rivers and lakes. Figs, olives, and oranges thrive in desert oases and have been harvested for centuries. Some desert areas rely on resource s brought from more fertile areas—food trucked in from distant farmlands or, more frequently, water piped from wetter regions.
Large areas of desert soil are irrigate d by water pumped from underground sources or brought by canal from distant rivers or lakes. The booming Inland Empire of southeastern California is made up of deserts the Mojave and the Sonoran that rely on water for agriculture, industry, and residential development.
Canal s and aqueduct s supply the Inland Empire with water from the Colorado River, to the east, and the Sierra Nevada snowmelt to the north. A variety of crops can thrive in these irrigated oases. Sugar cane is a very water-intensive crop mostly harvested in tropical regions. However, sugar cane is also harvested in the deserts of Pakistan and Australia.
Water for irrigation is transported from hundreds of kilometers away, or drilled from hundreds of meters underground. Oases in desert climates have been popular spots for tourists for centuries. The Dead Sea has had flourishing spas since the time of King David. Air transportation and the development of air conditioning have made the sunny climate of deserts even more accessible and attractive to people from colder regions.
Desert parks, such as Death Valley National Park, California, attract thousands of visitors every year. But in cities, structures like buildings, roads, and parking lots hold on to daytime heat long after the sun sets. This is called the urban heat island effect.
It is less pronounced in desert cities than cities built in heavily forested areas. New York was built on wetland habitat, and Atlanta was built in a wooded area. They may be only slightly warmer than the surrounding desert.
Deserts can hold economically valuable resources that drive civilizations and economies. The most notable desert resource in the world is the massive oil reserve s in the Arabian Desert of the Middle East. More than half of the proven oil reserves in the world lie beneath the sands of the Arabian Desert, mostly in Saudi Arabia.
The oil industry draws companies, migrant workers, engineers, geologist s, and biologist s to the Middle East. Desertification Desertification is the process of productive cropland turning into non-productive, desert-like environments. Desertification usually happens in semi-arid areas that border deserts.
Human activities are a primary cause of desertification. These activities include overgrazing of livestock , deforestation , overcultivation of farmland, and poor irrigation practices. Overgrazing and deforestation remove plants that anchor the soil. As a result, wind and water erode the nutrient -rich topsoil.
Hooves from grazing livestock compact the soil, preventing it from absorbing water and fertilizer s. Agricultural production is devastate d, and the economy of a region suffers. The deserts of Patagonia , the largest in South America, are expanding due to desertification. Patagonia is a major agricultural region where non-native species such as cattle and sheep graze on grassland.
Sheep and cattle have reduced the native vegetation in Patagonia, causing loss of valuable topsoil. More than 30 percent of the grasslands of Argentina, Chile, and Bolivia are faced with desertification.
People often overuse natural resources to survive and profit in the short term, while neglecting long-term sustainability. Madagascar, for instance, is a tropical island in the Indian Ocean.
Seeking greater economic opportunities, farmers in Madagascar engaged in slash-and-burn agriculture. This method relies on cutting and burning forests to create fields for crops. Unfortunately, at the time farmers were investing in slash-and-burn agriculture, Madagascar experienced long-term droughts. With little vegetation to anchor it, the thin topsoil quickly eroded. Rapid population growth also can lead to overuse of resources, killing plant life and depleting nutrients from the soil.
Since the s, Lake Chad has shrunk to half its size. Desertification has severely reduced the wetland habitats surrounding the lake, as well as its fishery and grazing lands.
Desertification is not new. Millions of people had to leave their farms and seek a living in other parts of the country. Desertification is an increasing problem. Every year, about 6 million square kilometers 2. The Sahara Desert crept kilometers 39 miles south between and South Africa is losing million metric tons short tons of topsoil each year. Many countries are working to reduce the rates of desertification. National Geographic - Inside: Sumo Kids.
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