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5. Soil: The Living Skin of the Earth

   

2005

15 December 2005. Prairie: Long-Range Forecast. By Candace Savage, Forest Magazine, Winter 2006. Excerpt: In 1960, 3 million acres of land were designated national grasslands, and put under U.S. Forest Service purview. There are twenty national grasslands, all managed by the Forest Service. ... the Loess Hills in Iowa, the Mescalero Dunes in New Mexico, the Black Hills Coniferous Forest in South Dakota, the Little Missouri Mountains in Montana-and others in almost every region. Candace Savage's book Prairie: A Natural History explores these remarkable ecosystems, celebrating this oft-unsung landscape with perspective and affection. ...when the Earth is losing species at an average rate of one every twenty minutes-the wide-open spaces of the Great Plains are a landscape of hope. ...According to a recent "biological-trends assessment" conducted by a team of researchers from several western universities, a total of about 1.2 million square kilometers (465,000 square miles) of natural grassland has been destroyed in the western United States since the onset of intensive settlement. Of these losses, almost 10 percent-110,000 square kilometers (43,000 square miles), an area half the size of Kansas-were incurred between 1950 and 1990. ... the destruction is relentless. In Colorado alone, more than 1,100 square kilometers (420 square miles) of farm and ranch land are lost every year, and the rate is accelerating. ... this continuing assault on the prairie ecosystem imposes an escalating stress on species that rely on wild grasslands for their survival. ...The cause of prairie restoration has found some unexpected advocates, among them the Iowa Department of Transportation. ...What the state does have...is a go-anywhere grid of roads, all of which have vegetated margins. Taken together, these strips add up to about 2,000 square kilometers (roughly half a million acres) of unproductive land that requires mowing, spraying and other regular maintenance. In an attempt to reduce costs in the late 1980s, the transportation authorities began to experiment with the use of native plants, on the assumption that they were adapted to local conditions and could look after themselves. Since then, more than 20,000 hectares (about 50,000 acres) of roadside have been seeded, a little more every year, to either a four-grass mixture-typically big and little bluestem, side- oats grama and Indian grass-or to a colorful assortment of native grasses and wildflowers. The results have exceeded all expectations. In addition to controlling expenses, the flower-rich plantings in particular have become slender oases of life, blooming not only with flowers but also with butterflies. In 2001, for example, researchers found five times as many butterflies and twice as many species in the high-quality restorations as in comparable grassy or weedy ditches...

Fall 2005. Prairie: Home on the Range. By Candace Savage. Forest Magazine. Excerpt: In 1960, 3 million acres of land were designated national grasslands, and put under U.S. Forest Service purview. There are twenty national grasslands, all managed by the Forest Service. ...Rangelands-expanses of native grassland that are grazed by livestock-exist only where the prairie has somehow managed to escape the plow, usually because the soil is too dry, too thin, too rocky, or too steep to be suitable for crops. ...In some ways, the introduction of domesticated livestock onto the Great Plains was not much of a shock to the ecosystem. Bison and cattle belong to the family Bovidae, and trace their ancestry back to India and China some 2 million years ago. ...This is not to say that the introduction of cattle to the Great Plains has been completely benign-it has not. ... bison like to throw themselves on the ground and flail around in the dirt, a self-care routine that is thought to coat the skin with dust and offer protection from biting insects. In the process, they wear away shallow bowls, or "wallows" in the earth. By rubbing out the grasses from these hollows, bison create openings for other kinds of plants. The increased diversity of plants available for shelter and food also augments the diversity of insects, birds, and mammals. If the depressions fill with water, they provide seasonal habitat for aquatic insects and water-loving shorebirds. Or at least they used to. Because cattle do not wallow, this dynamic has been lost....

 

 

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2004

18 March 2004. NASA RELEASE: 04-095. NASA EXPLAINS "DUST BOWL" DROUGHT. NASA scientists have an explanation for one of the worst climatic events in the history of the United States, the "Dust Bowl" drought, which devastated the Great Plains and all but dried up an already depressed American economy in the 1930's. Siegfried Schubert of NASA's Goddard Space Flight Center, Greenbelt, Md., and colleagues used a computer model developed with modern-era satellite data to look at the climate over the past 100 years. The study found cooler than normal tropical Pacific Ocean surface temperatures combined with warmer tropical Atlantic Ocean temperatures to create conditions in the atmosphere that turned America's breadbasket into a dust bowl from 1931 to 1939. The team's data is in this week's Science magazine.

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