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What Type of Biome Is the Desert?

Deserts, cold or hot, are dry. That's the one overwhelming fact of any desert biome, or ecological community, be it the sands of the Sahara or the ice of the Antarctic plain. Deserts, say scientists, receive less than 20 inches of rain or snow a year. It's a mistake, though, to think of deserts as lifeless. The desert biome, in its own way, is as complicated and interesting as any rainforest.

Hot and Dry
- These desert biomes are so hot that even when it rains, which is rarely, the rain can evaporate before it reaches the ground. The Sahara, inland Australia and the United States' Mojave are hot and dry desert biomes, with wide temperature fluctuations between scorching days and chilly nights. Nevertheless, ground-hugging plants use their water-conserving tricks to survive, and insects, spiders and small rodents somehow manage to flourish.
Semiarid Desert
- Summers are long and dry; perhaps there's a burst of rainfall in the winter. Nights are cool, not usually cold, and days are warm but not stovetop-hot. Condensation of dew at night helps make up for the lack of rainfall. Spiny and glossy plant leaves help minimize water loss and reflect away sunlight. More and bigger mammals, such as rabbits and skunks, are found here. The Great Basin in the American Southwest is this kind of desert, but so are parts of Greenland, Newfoundland and Russia.
Coastal Desert
- All that nearby ocean water, and yet it's the driest desert in the world. The complex interplay of ocean currents and winds keeps away rainfall, so in the Atacama in Chile, on the Pacific coast of South America, rainfall is measured in millimeters. It can receive less than 1/25 inch of rain in 20 years. Plants have shallow but widespread roots, the better to soak up and trap any moisture, and amphibians and insects can lay dormant underground for months at a time.
Cold Desert
- Summers are short, moist and (relatively) warm; winters are long and cold. Along the fringes of the Antarctic continent, flowering plants like the Antarctic hair grass and pearlwort can be found. Mosses, lichen and fungi also stubbornly cling to the ice continent. Penguins lay their eggs on nests scraped together from rocks, or dispense with nests altogether and hold the eggs on their feet. In cold deserts in other parts of the world, such as the Arctic, mammals survive by burrowing.

Nature