9781422277522

A buffalo herd grazes on prairie grass in the Maxwell Wildlife Refuge near Canton, Kansas. All over the world, grasslands have been taken over by people, to grow food or raise farm animals.

What Are Grasslands? G rasslands are the most widespread biome on land, covering one-fifth of the land surface. They are areas where grasses are the dominant plants. There are rel- atively few species of grasses, but each grows in huge numbers, densely packed together. Directly or indirectly, grasses provide a very large proportion of human food. Grasslands first appeared about 65 million years ago, dur- ing the Cenozoic era. This was a time when the Earth’s climate was becoming cooler and drier. Grasslands cover land that is too dry to support trees, which need a damp climate, but is not so dry as to be desert. The main types of grassland are temper- ate and tropical grasslands. Temperate grasslands include the prairies of North America, the pampas of Argentina and the cool steppes of eastern Europe and Asia. Tropical grasslands range from the Sahel, where sparse clumps of grass struggle to survive among stunted bushes on sandy ground, to the vast

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