Habitat loss highest near ethanol plants
Millions of acres of wildlife habitat have been lost to corn production across America's heartland in recent years and the damage is worst nearest ethanol production plants.
That's the finding of a new study published Tuesday in the journal Environmental Research Letters that found nearly 4.2 million acres of habitat, generally prairie grasslands, converted to crops within 100 miles of an ethanol plant between 2008 and 2012 alone.
Those are the years immediately after a federal mandate was enacted requiring ethanol to be blended with gasoline. Ethanol plants convert corn to alcohol often used as fuel.
Researchers from the University of Minnesota Duluth, University of Wisconsin and the National Wildlife Federation assessed satellite imagery and land classification data from the U.S. Department of Agriculture to determine conversion rates from non-farmland into farmland in the years following passage of the federal Renewable Fuel Standard.
The research — funded by the National Science Foundation — found that within the 100-mile radius, wildlife habitat loss increased closer to the ethanol plant. Habitat loss decreased significantly as the distance from ethanol plants increased.
The impact has been profound on populations of wildlife and birds, such as ducks and pheasants, but also pollinators such as butterflies and native, wild bees.
The study looked at the hotbed of ethanol plants across Minnesota, the Dakotas, Wisconsin, Iowa, Illinois, Nebraska, Michigan, Indiana, Oklahoma and Texas, among other states. It found the highest conversion rates not near long-standing ethanol plants in Minnesota and Iowa but in areas where corn was a relatively new crop — generally south and west of the traditional corn range — in the Dakotas, Kansas, Missouri and Nebraska.
"Our analysis shows an undeniable connection between corn ethanol production and habitat destruction," said study co-author Ben Larson, senior manager of forestry and bioenergy for the National Wildlife Federation. "This massive loss of wildlife habitat is happening under the radar of the public and many policy makers even though the impacts are enormous."
Larson suggests that the federal government rethink the ethanol mandate, a move that's praised by some fiscal conservatives and environmental groups in Washington but that has been fiercely fought by farm-state lawmakers whose corn-growing farmers enjoy the increased demand for their crop that ethanol brings.
The study's lead author, ecologist Christopher Wright at UMD's Natural Resources Research Institute, said the conversion of grassland to corn has even broader impacts than simply wildlife habitat, including global climate change. Undisturbed grasslands absorb carbon dioxide while intensive corn farming releases carbon into the atmosphere.
"If there's a net shift in grass pastures or native prairies to corn, there will likely be associated landscape impacts, like increased water runoff and reduced land connectivity for wildlife," Wright said. "It also impacts the atmosphere, potentially turning lands that are carbon sinks into carbon sources."
The study builds on a previously published analysis by researchers at the University of Wisconsin that found 7 million acres nationwide were converted to crop production from 2008 to 2012 and that corn was the most common crop planted after conversion. Many of those acres were taken out of the federal Conservation Reserve Program and related programs aimed at preventing soil erosion, improving water quality and preserving wildlife habitat.
The study found nearly 2.7 million acres of arable non-cropland converted to cropland within a 50 mile radius of ethanol plants. From 50 to 100 miles out, an additional 1.5 million acres of cropland expansion was found. Outside 100-mile radius, conversion rates dropped substantially.
"This research demonstrates the Renewable Fuels Standard's devastating impacts on wildlife habitat," said Collin O'Mara, president and CEO of the National Wildlife Federation. "We look forward to working with Congress and the EPA to adopt reforms that will help recover impacted duck, pheasant, songbird and monarch populations and restore our nation's treasured grasslands."