desert Article

desert summary

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Below is the article summary. For the full article, see desert.

desert, Large, extremely dry area of land with fairly sparse vegetation. It is one of the Earth’s major types of ecosystems. Areas with a mean annual precipitation of 10 in. (250 mm) or less are generally considered deserts. They include the high-latitude circumpolar areas as well as the more familiar hot, arid regions of the low and mid-latitudes. Desert terrain may consist of rugged mountains, high plateaus, or plains; many occupy broad mountain-rimmed basins. Surface materials include bare bedrock, plains of gravel and boulders, and vast tracts of shifting sand. Wind-blown sands, commonly thought to be typical of deserts, make up only about 2% of North American deserts, 10% of the Sahara, and 30% of the Arabian desert.