Conserving wildlife migrations is part science, part policy

The wide-open spaces of the American West contain one of our nation’s greatest assets: a vast network of public lands that in turn support an abundant variety of wildlife. These lands and animals form the fabric of many communities, enriching local economies and cultures, supporting outdoor recreation and boosting the ecological health of the region. That’s why it’s vital that the migration routes of our wildlife — and the habitat these routes connect — remain as free as possible of human-made impediments such as roads and development.

Fortunately, there’s promising news on this front. Interior Secretary David Bernhardt recently suggested that he would expand an initiative dedicated to identifying and conserving wildlife migration corridors in Western states to include additional big-game species and more of their habitat. This would further empower federal land and wildlife agencies to work with states to ensure that science is guiding land management decisions in crucial habitat for species such as mule deer, elk and bighorn sheep. 

{mosads}The benefits of this science-centered approach extend far beyond conservation. As the Western Governors’ Association noted in a 2017-2018 policy resolution supporting science-based land management, “Large intact and functioning ecosystems, healthy fish and wildlife populations and ample public access to natural landscapes are significant contributing factors to the West’s economy and quality of life.”  

But conserving the West’s wildlife populations and the migration corridors they use to find food and water, to escape predators and to connect with other animal populations, is a daunting task in a region where all the key markers of growth — human population, energy development, road construction and other development of land that was formerly open space — are rapidly rising.

If corridors are lost or blocked, animals face what scientists call “habitat fragmentation,” in which contiguous areas are subdivided and wildlife species isolated from one another. And if that happens, as University of Wyoming ecologist Brett Jesmer explained in a radio interview last year, “it takes a long time for these migrations to re-establish because they require animals to learn about their landscape, pass that knowledge on to young, who then augment that knowledge with their own experiences and then pass that on to young and so on and so forth.”  

Researchers from the University of Wyoming have found that, as a general rule, mule deer populations that retain their historic migratory pathways are healthier and more robust than those who don’t. In fact, habitat fragmentation has played a role, along with factors such as disease, in the mule deer population plummeting by more than 50 percent in some places across the West, with declines observed in other big game species as well. In the Yellowstone ecosystem of northwest Wyoming and parts of Montana and Idaho, development has caused pronghorn to stop migrating through six of eight historic corridors.

In the face of the challenges, sound, science-based federal policy would help the West strike a healthy and prosperous balance between growth and conservation. Recent conversations between officials at the Interior and Transportation departments might lead to increased support for ensuring that highway projects include areas where wildlife can cross roads safely, which would also greatly increase driver safety — a major part of DOT’s mission. This could be done by keeping migration routes free of development, building or retrofitting highway underpasses or overpasses for wildlife passage and seeing that seasonal habitat is managed in a way to minimize stress on wildlife populations. 

At the state level, policymakers have begun building a framework for identifying and conserving migration routes. Wyoming has been a leader in protecting crucial big game habitat — including “stopover areas,” where animals spend additional time foraging during migration — and there are signs that other states are moving in a similar direction.

For example, New Mexico’s governor, Michelle Lujan Grisham (D), just signed a bill that will result in the identification of priority wildlife migration routes while directing the state wildlife and transportation departments to work together to conserve the populations of wildlife that use the routes. 

The time is right: In part thanks to lower costs and wider use of GPS-enabled collars that allow scientists to track and study herds and individual animals, experts know more than ever before about migration routes and why they’re so important in supporting healthy populations of game. 

By enacting policy to keep these corridors functioning, while restoring some that have already been lost, governments can help keep the vast natural spaces of the west healthy without compromising economic growth — ensuring that our country’s Western range continues to be dotted with deer, elk and other iconic species while keeping the surrounding communities thriving far into the future.

Tom Wathen leads The Pew Charitable Trusts’ land conservation projects, which span the Americas from the Arctic Ocean to the tip of South America.