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Land conversion due to the Renewable Fuel Standard may harm endangered species, study says

Katie Peikes
IPR file
The analysis says there has been a lot of expansion in cropland to produce corn for biofuels under the Renewable Fuel Standard, The land conversion and growing corn can degrade wildlife habitat which can harm species protected under the Endangered Species Act, such as Poweshiek skipperlings.

TheRenewable Fuel Standard requires a certain amount of renewable fuels, including ethanol, to be blended into the nation’s transportation fuel supply.

But the federal policy may affect endangered species and their necessary habitat when farmers convert land into cropland to grow more corn, which is processed into ethanol, according to a new analysis in the journalBiological Conservation.

“When you plow up a grassland to plant additional corn or switch other crops to something that's more intensive, like corn production, that generally results in greater nutrient pollution to waterways,” said University of Wisconsin-Madison researcher Tyler Lark, who authored the analysis.

Lark’s analysis says the land conversion and growing corn can degrade wildlife habitat, which can harm species protected under the Endangered Species Act.

The Endangered Species Act lists certain fish, wildlife and plants as “threatened” or “endangered” in order to draft plans that will aid their recovery. Under the ESA, federal agencies must consult with the U.S. Fish and Wildlife Service or National Marine Fisheries Service to ensure anything they do won’t put threatened species in jeopardy. The U.S. Environmental Protection Agency, which implements the RFS, has not consulted with those agencies, Lark’s study says.

But Lark said there are ways to reduce or reverse the impacts of renewable fuels policy on threatened and endangered species. Expanding the use of cover crops and other conservation practices on corn acres, Lark said, could provide nesting habitat, reduce nitrate runoff and help these species.

The analysis highlights three potentially impacted species: Whooping cranes, Poweshiek skipperling and black-footed ferrets. Poweshiek skipperling are endangered butterflies that live in tallgrass prairie in Iowa and a few other Midwest states. The analysis says widespread conversion of grasslands into corn production and the increased use of herbicides could harm this species.

Stephen Dinsmore, the department chair for Iowa State University’s Natural Resource Ecology and Management Department said though he is “not intimately familiar” with the Renewable Fuel Standard, “there are a number of mechanisms that can cause the habitat that’s required by these species to decline.”

“The RFS might be one of those,” Dinsmore said. “I think there are other mechanisms as well. An analysis that tries to tease a part is an interesting exercise, but I’m not sure it’s telling the whole story.”

In a statement, the National Wildlife Federation commended the research and urged the EPA to reassess how it carries out the Renewable Fuel Standard so that critical wildlife habitat such as grasslands and wetlands aren’t put into production for biofuels.

“The Endangered Species Act has been one of the most effective conservation laws of the past half-century,” said David DeGennaro, a senior climate and biofuel specialist at the National Wildlife Foundation, “but the best way to recover species is to address challenges before they decline to the point of requiring listing.”

Monte Shaw, the executive director of the Iowa Renewable Fuels Association, rejected Lark’s land-use change findings. He said there has been a “shifting of acres between principal crops from year to year” but not “widespread land-use change” for corn.

“We have less acres planted to principal crops than we have since the RFS went into effect and the growth in the ethanol industry went into effect,” Shaw said. “To say that there's been land-use change is hard for us to swallow.”

Biofuels trade association Growth Energy, argued in a statement that there’s no connection between the RFS and impacts to endangered species.

“American-made bioethanol can, and does, deliver major climate benefits, and there is no proven link between the RFS and significant adverse effects to listed species and critical habitat,” said CEO Emily Lark.

A spokesperson for the EPA said the agency is “reviewing the study and its findings.”

Journal reference: Lark, T. (2023). Interactions between U.S. biofuels policy and the Endangered Species Act. Biological Conservation, 279. https://doi.org/10.1016/j.biocon.2022.109869

Katie Peikes was a reporter for Iowa Public Radio from 2018 to 2023. She joined IPR as its first-ever Western Iowa reporter, and then served as the agricultural reporter.