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Ice Age
Arctic tundra is another kind of plain. Deep sheets of ice covered the land during ice ages, scouring the surface flat. In frigid areas of the planet, tundra, characterized by thick, black mud and permanently frozen subsoil, dominates the landscape. Trees won't grow in a tundra, but a lack of water isn't to blame. It's the frozen ground. Even in the summer the sun thaws only a few inches of soil, leaving the permafrost below the surface hard as stone. This frozen layer of earth does not absorb moisture well, so water runs off it like it does a rock. Not particularly welcoming to tree roots. Mostly a few short grasses, mosses, lichens and heath grow in the tundra in the short summers.
It's a Zoo Out There
Of course, all plains vary in the animals and plants that inhabit them. There are the yaks, pika and Tibetan foxes of the highest plain in the world, the Tibetan Plateau. Not very far away, just over the Himalayas, are the pygmy hogs, elephants and towering grasses of the Long Grass Plains of India. Two plains with very different inhabitants.
Then there's South America's 290,000-square-mile (750,000-square-kilometer) Pampas of Argentina that once ran wild with rheas, nutrias, vizcachas, opossums and the endangered Pampas deer. Across the Atlantic there are lions, zebras and elephants on the African savannah — another plain — and more variety still on the South African veldt.
Threats
One of the greatest threats to the plains of Earth is climate change. A climate shift that sends more water to an arid plain, or warmth to tundra plains, would make those places more hospitable to trees, which would, in turn, dramatically change the rest of the flora and fauna. On the other hand, should climate change bring less rain to the Great Plains or the Mongolian grasslands, it could lead to a permanent "dust bowl" condition. That would be an economic, environmental and humanitarian disaster.
At the moment, climate modelers haven't honed their predictions to say for sure what will happen. The only thing certain is a change will occur.
Oddly enough, many of these plains may contain the seeds to their own salvation. Recently biologists in Minnesota have discovered that when native prairie grasses are allowed to grow on depleted farmlands, the soils starts gaining carbon pretty quickly — even of the grasses that are mowed — which mimics grazing by buffalo or prairie fires by cutting away the upper part of the plant.
What's even more compelling is that the mowed grass can then be fermented and made into ethanol that can run cars and electrical generators. That means these grasses offer a fuel that is "carbon-negative," i.e., it lowers the carbon dioxide levels in the atmosphere and fights global warming. Not even corn ethanol can make that kind of climate-friendly claim.
What's more, in areas where prairie grasses are allowed to grow instead of cash crops, wildlife is also coming back — prairie chickens, pheasants and mule deer, for instance. The plains, it seems, may someday save not only themselves, but the planet.
