Most of us associate the desert ecosystem with high temperatures, but there are actually many in the world that are quite cold.
The single defining nature of a desert is its dryness (aridity). About one-fifth of the Earth’s surface is desert (33.7 million square kilometers) occurring where rainfall is less than 50 cm a year, very localized and unpredictable.
We may think of deserts as having little or no life but in fact they have an abundance of highly specialized plants and animals, second only in numbers to tropical rainforests.
Very few large mammals are found in this ecosystem because they are not capable of storing sufficient water or of withstanding the heat.
Despite the hostile environment, human beings have managed to survive in some of these deserts (more than 2,000,000,000 people occupy these areas). The Aborigines in Australia have lived in the deserts for over 30,000 years; the Bushman have inhabited the Kalahari for 20,000 years; Nomadic tribes such as the Tuareg call the Sahara their home and Arab caravans have crossed it since the 10th century.
Deserts are divided into two major types – Hot and Cold. Hot deserts are further subdivided into Hot & Dry and Semi-Arid desert types.
Desert Ecosystem References: