What is a Desert?
A desert is a place where there is little to no rain or snow. Deserts cover more than one fifth of the earth’s surface and are on every continent except Europe and Antarctica. A desert gets less than 10 inches (25 centimeters) of rain annually. In fact, the Atacama Desert in Chile hasn’t had rain for the last 40 years, making it t he driest place on Earth.
Only one tenth of the world’s deserts are sandy. The rest of the deserts are mountainous and rocky. The largest desert in the world is the Sahara Desert in northern Africa. It has over 3 million square miles (7,770,000 square kilometers) of rock, mountains and sand. Not all deserts are hot. In the Gobi desert in China, the winter temperatures can get as low as -30 degrees Fahrenheit
(-34 degrees Celsius).
The largest deserts are formed north and south of the equatorial rain forests. Moist air warmed by the sun rises over the equator and eventually cools at a high altitude. The cool air eventually falls down as rain. During this process, the cool and now dry air spreads north and south of the equatorial rain forests. The air then sinks and warms up and becomes hot, dry winds that stop any moisture from coming to the desert.
Why is the Desert Important to Biodiversity?
Often times we think about the desert as a sandy place with just cacti, but the desert is really a place with a lot of biodiversity. Many different plants and animals have adapted to this hot, dry environment.
The saguaro cactus is the largest species of cactus in the U.S. It can grow to be 50 feet (15 meters) tall and live to be more than 200 years old. The saguaro grows only a few inches each year. Insects, birds and bats feed on the nectar of its cactus flowers.
Different species of birds have adapted to finding food in the desert. Cactus wrens, hawks and roadrunners get all the moisture they need by feeding on in sects, lizards and small animals.
The eastern spadefoot toads emerge from their underground holes after it has rained and lay their eggs in a puddle. The eggs hatch and the tadpoles grow quickly. When they run out of food, the biggest tadpoles eat the smaller ones. Just as the puddle dries up the tadpoles turn into toads and hop into holes waiting for a rainstorm.
Camels have thick fur on their backs to block direct heat from the sun. The fur on their bellies is thin so they can lose body heat. A camel’s body heat can rise 11 degrees Fahrenheit (6 degrees Celsius) before it starts to sweat. Compare that to a human who can get a fever if his or her temperature rises by more than one degree. A camel can go for weeks without water because it stores the energy in its hump.
People also live in the desert. The aborigines of Australia arrived from Asia about 4,000 years ago. These people have developed ways to live in the desert with little water. The San people of the Kalahari Desert in southwest Africa have developed similar ways of surviving.
What Are the Threats to the Desert?
Believe it or not, global warming is a threat to desert life. Rainwater collects in underground lakes and sometimes flows to the surface. These water holes are called oases. If the earth overheats it can dry up these oases, hurting all the plants and animals  that depend on them. Also, global warming increases the risk of wildfires that can burn down desert plants.
The saguaro cactus is only found in the Sonoran Desert. The Sonoran Desert is located in the southwestern part of the United States and in part of Mexico. The saguaro cactus is endangered because it does not grow fast enough to replace the saguaros that die naturally or die because of the humans that cut down the saguaro. Many animals depend on the saguaro. If the saguaro goes extinct, it will dramatically disrupt the food chain and harm biodiversity.
Other threats to the desert wildlife include mining and oil and gas production. Deserts have also been used as nuclear testing grounds. Off-road vehicles can also be a threat to desert habitats.
How You Can Help
One way to help the desert is to help prevent global warming. You can do your part to help conserve energy in a number of ways: turn off lights when you are not using them, ride your bike to school instead of drive, don’t let the water from the tap run, recycle, waste less and use less paper.
If you visit the desert, respect the plants and animals that live there. If you are riding in an off-road vehicle, stick to the designated trails. Don’t take the plants or animals that live in the desert. These plants and animals belong in their natural habitat.
Write letters to your government officials telling them you think conserving the desert is important. |
