Wildlife habitat near corn-ethanol refineries has been destroyed at a fast pace since a federal law was passed to produce more biofuels.

A new study says within a 100-mile radius of ethanol plants, 4 million acres across the U.S. have been converted to agricultural use in the four years after passing the Renewable Fuel Standard.

Landscape ecologist and study co-author Chris Wright at the University of Minnesota-Duluth says the Corn Belt states have seen a lot of habitat destruction.

“It was the ethanol refineries out on the periphery of the industry where we saw significant land-use change,” he states.

Minnesota is a huge ethanol producer

Minnesota is the fourth highest state when it comes to ethanol production, with nearly 1.2 billion gallons last year. Congress passed the standard in 2007 to require blending corn-based ethanol and other renewable fuels with gasoline.

Ben Larson, senior manager of forestry and bioenergy with the National Wildlife Federation, says the federal law contains language to protect wildlife habitat by not allowing recently converted land to be used for biofuel production.

But Larson, a report co-author, says the Environmental Protection Agency took a shortcut in implementing the policy. Instead, it adds the total of all cropland and looks at whether it increases over time at the national level.

“Well, at that national level, you really can’t see the concentrated pockets of conversion that we show are happening around ethanol plants,” he points out. “It’s like if you pull back from the earth far enough, you lose sight of where the impacts are happening.”

Another study found 7 million acres of land nationwide had been converted to crop production in the four years following the standard’s passage, with corn being the most common crop.

Larson says this kind of conversion rate has a serious impact on wildlife.

“For the wildlife species that rely on grasslands and wetlands that are being converted to cropland, habitat loss is not an academic issue,” he states. “For instance, grassland birds as a group have suffered the most severe population declines of about any group of species – and that’s largely as a result of habitat loss.”

Researchers at the University of Minnesota-Duluth, the University of Wisconsin and the National Wildlife Federation conducted the study.