THE DIVERSE DESERT

The Southwest's Ecoregion 10 hosts a surprising assortment of landscapes and life

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Above: This is the scene many of us picture when we think of the Sonoran Desert - a landscape dotted with saguaro cactus and other prickly plants.

However, the desert is just one biome of many that occur in Ecoregion 10, which covers a large swath of the American West.

FOLKS USED TO GET their kicks down on Route 66—but no more. The southwestern desert has reclaimed much of that storied highway; driving on what’s left of it now, you’d call it bleak and lonely.

But HA! That's just a façade. This is the National Wildlife Federation's “Ecoregion 10,” also known as the Sonoran Desert. Over 100,000 square miles of its land cover the southwestern United States and northwestern Mexico. According to the National Park Service, its landscape diversity rivals that of any other terrestrial ecosystem on earth.

This desert isn't just all dry sand and furnace-like temperatures. Five of the six kinds of major ecologies recognized by scientists around the world exist within the Sonoran Desert. (The sixth of these biomes, as they're called, is tundra, and a bit of it exists just 100 miles to the north, high in Colorado's Rockies.)

Why is this southwestern desert so rich in diversity? Because of the folded landscape. It rises from desert basins that are less than 2,000 feet elevation, to the thornscrub biome (between 2,500 and nearly 4,000 feet elevation), through semi-desert grasslands (between 3,800 and 4,500 feet), up into the interior chaparral (between 4,500 and 5,500 feet) and then up to the madrean evergreen. woodlands (between 5,000 and 6,000 feet). Finally it reaches land above 6,000 feet, denoted as temperate forest by plant scientists.