Experts, researchers urge Iowa to adopt connectivity corridors to preserve wildlife

To curb habitat loss and help protect wildlife across the state, experts are pushing for Iowa to adopt “connectivity corridors.”

Connectivity corridors — also known as ecological corridors — are stretches of land or water that connect isolated habitats to allow more movement for wildlife and natural ecosystems.

A report published by the Sierra Club’s Iowa chapter states that establishing connectivity corridors would lessen habitat fragmentation across the state.

Thomas Rosburg, a professor of ecology and botany at Drake University, said connectivity corridors are crucial for plants to be pollinated and for their seeds to be moved around and replanted.

“Plants moving across the landscape, they only can move by little, tiny steps, a few dozen meters at a time,” Rosburg said. “In order for that movement to happen, little steps by little steps, there needs to be a corridor of suitable habitat that connects those remnant prairies, wetlands and forests to provide a route, to provide safe passage across this otherwise inhospitable landscape. These corridors are crucial.”

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As a result of species in fragmented areas not being able to travel far, Dave Hoferer, an associate professor of biology with Briar Cliff University in Sioux City, said species in fragmented habitat areas are subject to potential inbreeding and “extinction debt.”

Hoferer said extinction debt occurs when the adults of a species can live a normal life span but cannot leave behind enough offspring to replace them once they die.

“Thus, the population slowly declines over time,” Hoferer said. “We might measure a population today and say it's healthy, but decades from now, we can say, ‘Wow, this population is really in decline.’”

Hoferer said that connectivity corridors are a “very obvious” way to reverse this trend in Iowa.

“Species are naturally on the move,” Hoferer said. “If there are habitat corridors that they can disperse along, then they can find shelter. They can find food along the way before they find another core area which could be another state preserve in which they could live, and establish their own home and actually breed and produce new members of the species. Without these corridors, it becomes much more difficult for these organisms to move around the environment.”

Connectivity corridors can include rivers or streams, reintroducing prairie land and native plants and wetlands.

Wally Taylor, who serves as the legal chair for the state’s Sierra Club chapter, said that roadways can be used as another type of corridor.

The Iowa Department of Transportation’s Living Roadway Trust Fund has been working to incorporate native and prairie plants into roadside ditches, with the hope that cars driving by will pick up the seeds and they will be replanted elsewhere.

“Prairie on our roadways could help again, especially plant species, and help them move across a landscape,” Taylor said.

Implementing the corridors

In terms of getting more corridors implemented across the state, Taylor said that a good first step would be to ask state agencies — like the Department of Transportation and the Department of Natural Resources — to incorporate funding for these projects into their budget and work with them to plan where they should be located.

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However, Rosburg said that to complete projects like this, there must be ample land across Iowa.

“That's always the challenge in Iowa, right? If you're going to put habitat back on the land, you have to have control of the land and so much of our land, of course, is privately owned,” Rosburg said. “So that means that we have to find ways to get engaging private landowners, especially for those riverine corridors, most of the private land goes right up to the river.”

Rosburg said that in order for it to work, taxpayers would have to support the corridors and be willing to put money into the program.

“That's what we're trying to do with this report, to bring this to the attention of Iowans, explain why it's important and explain that maybe we could spend less money on things that don't benefit all Iowans and spend it on items that do benefit all of us and to benefit the environment around us,” Taylor said. “I think it's a matter of priority, a matter of political will, a matter of electing people who do care about the things that benefit all of us.”

Habitat loss in Iowa

Rosburg said that more than 86 plant species have become extinct in Iowa since the 1800s.

Currently, an additional 260 plant species — about 17 percent of native plants in the state — are considered endangered or threatened, he said.

Rosburg said the threatened and endangered plant species could rebound in Iowa with the help of corridors, which would allow the plants to have greater movement and populate in other areas.

Over the last 200 years, Rosburg said Iowa has lost more than 99 percent of its native prairies, 92 percent of the state’s wetlands and 75 percent of woodlands and forests.

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It is “a tremendous conversion from what once was a tremendously diverse and bountiful and productive landscape to again, a now landscape where biodiversity is severely threatened,” he said.

But the biggest driver of this, the experts said, is how much of Iowa’s land has been developed for agricultural use.

According to an Iowa State University report from 2024, about 29.9 million acres of Iowa’s land is in agriculture.

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Pam Mackey-Taylor, the Sierra Club’s Iowa chapter director and state lobbyist, said programs like the Iowa DNR’s Resource Enhancement and Protection program, or REAP, could help fund corridors throughout Iowa.

“Every county in Iowa has benefited from these funds, and the problem is it's statutorily recommended at $20 million annually, but the legislature has chosen to fund it at $12 million, significantly underfunding the projects that could be used for wildlife corridors and habitat enhancement,” Mackey-Taylor said. “REAP was extended to 2028 this year by the legislature, but that program needs to be extended beyond 2028 and needs to be given a secure future.”

Iowa isn’t the first state where experts are suggesting connectivity corridors to preserve ecosystems.

According to the Sierra Club’s report, California passed 22 bills between 2008 and 2023 to support the state’s natural habitat, three of which promoted wildlife corridors specifically.

New Mexico, Oregon and Virginia also have adopted legislation directing both transportation and wildlife agencies to “identify, prioritize and create” a wildlife corridor action plan.

Taylor said Iowa should follow suit and that the state should adopt an amendment to the Iowa Constitution, saying Iowans have the right to a clean and natural environment.

“This would make Iowa laws and local ordinances protect Iowa's natural heritage,” Taylor said. “This would say that the state and local government entities must evaluate the environmental impacts of their actions and carry out the action with the least impact.”

Download: Wildlife Connectivity Report by Sierra Club IA Chapter.pdf

Olivia Cohen covers energy and environment for The Gazette and is a corps member with Report for America, a national service program that places journalists in local newsrooms to report on under-covered issues.

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Comments: olivia.cohen@thegazette.com