From the American Prospect comes a fine piece of enterprise journalism on the shocking rates at which native grasslands are being converted to row crops in a region stretching from western Minnesota across the Dakotas, Nebraska and Iowa.

“Plowed Under,” written by Jocelyn C. Zuckerman and published last week with support from the Food & Environment Reporting Network, takes the reader on a tour of perhaps familiar terrain where losses of natural landscapes and plant communities are causing soil erosion, degraded water quality, habitat destruction and more — often with the strong support of federal farm policies.

This is not a new trend but clearly an accelerating and also, I think, a significantly under-reported one.

Last November, the Associated Press touched on grassland losses in its investigation of unintended environmental harm said to be flowing from federal promotion of biofuels. This aspect was one of the project’s major strengths, as I said at the time, but the focus was on policies thought to be creating the problems, and so the consequences got fairly cursory attention.

Zuckerman’s piece takes up the consequences and looks far deeper — right down to the long roots of native prairie plants whose capacity for carbon sequestration can give grasslands the same potential as woodlands to mitigate global warming.

At the statistical center of the story is a 2013 study by Chris Wright, a landscape ecologist at South Dakota State, who analyzed land-use data gathered by satellite at National Agricultural Statistics Service to measure grassland-to-cropland conversion in the Western Corn Belt states of Minnesota, Nebraska, Iowa and the Dakotas.  (His work was discussed by the AP as well.)

Wright found that those losses totaled more than 1.3 million acres from 2006 to 2011 as grassland was converted to corn and soybean cropping — in some areas, at a pace exceeding 5 percent per year of the grassland remaining. Those rates, Zuckerman said, “parallel the deforestations taking place in Brazil, Malaysia, and Indonesia.”

The shift represents the most rapid loss of grasslands since tractors began breaking sod on the Great Plains in the 1920s. Most of the conversion is happening on lands that are at risk from erosion or drought, and, in some cases, both.

While grasslands may not be the most charismatic of landscapes — “Anyone can love the mountains,” the local saying goes, “it takes soul to love the prairie” — they, and the wetlands that tend to go along with them, are among the most important ecosystems on the planet.

For one thing, they contain disproportionately high numbers of plant and animal species. (More than a third of species on the U.S. endangered species list live only in wetlands.) They also provide a range of critical “ecosystems services,” soaking up rain and snowmelt and slowly releasing water in drier seasons, thereby reducing flooding and erosion and improving water quality by filtering out fertilizers and pesticides that run off of farmland. …

Finally, and crucially, the deep-rooted grasses that constitute the world’s prairies hold massive amounts of carbon: nearly one-third of total stocks, almost as much as that stored by forests.

Another consequence, highlighted by High Country News last week: loss of habitat critical to bees and other pollinators, including monarch butterflies, whose declines now seem at least as traceable to losses of U.S. grassland habitat as to deforestation in Mexico.

The Wright paper, published by the National Acadamies a bit over a year ago, is available here;  among its conclusions are these:

Historically, comparable grassland conversion rates have not been seen in the Corn Belt since the 1920s and 1930s, the era of rapid mechanization of U.S. agriculture. Across the western Corn Belt, more than 99% of presettlement tallgrass prairie has been converted to other land covers, mostly agricultural, with losses in Iowa approaching 99.9% of an original 12 million hectares of tallgrass prairie.

Potential expansion of corn and soybean cultivation into remaining fragments of tallgrass prairie … presents a critical ecosystem conservation issue. Under the most likely climate change scenario for the Northern Great Plains, a 3- to 4-°C increase in mean annual temperature offset by a 10% increase in mean annual precipitation, much of the wetland habitat in the prairie pothole region is projected to be lost.

Among the efforts being raised against this wholesale conversion are those of The Nature Conservancy, which has called these grasslands the world’s most imperiled ecosystem, and the Environmental Working Group, whose spokesman told Zuckerman the changes constitute “a major, creeping, ecological disaster” and predicted that “If we continue down this road, we’re going to turn the Dakotas into another Iowa.”

The problem with putting it that way, alas, is that many an Iowan — or Minnesotan, Montanan or Mississippian — would consider this to be progress.

After all, we live in a time where issues of food supply and security loom on the horizon as perhaps the world’s second most difficult long-term resource problem, after water. Why shouldn’t land that’s capable of producing crops be put to use doing so?

Zuckerman gives the obligatory nod, required of every journalist when the subject is rural land conservation, to sportsmen. From her opening anecdote, set among disheartened pheasant hunters in a Montevideo, Minn., cafe, she surveys the game-depressing consequences of grassland conversion and also wetland loss, which tends to go hand-in-hand.

North and South Dakota, particularly the landscape known as the Prairie Pothole Region, a network of wetlands formed by glaciers 10,000 years ago, exude a moody, rugged outdoor allure. Overgrown puddles pock the undulating fields and shift from gray to shimmering silver when the sun peeks through the clouds. Known as “the nation’s duck factory,” the region is the breeding ground for more than half of North America’s migratory waterfowl.

And she visits a cattle rancher near Lowry, S.D., who has quite recently reformed his earlier wetland-wrecking practices in favor of producing beef on a natural landscape — in a small-scale, labor-intensive way — while respecting the buffers around a little stream as an application of his new philosophy that “there are some places that just aren’t supposed to be farmed.”

Arrayed against such impulses, however, are high commodities prices and a variety of federal policies and programs, from crop insurance to biofuels mandates, that encouraging cropland expansion and discourage conservation set-asides.

Adam Warthesen, of the Minneapolis-based Land Stewardship Project, is quoted in observing that “we have fashioned a farm policy that incentivizes putting more under the plow, and [the federal farm bill signed into law in February] doubles down on that.”