Conservation groups have set up cameras at the San Bernardino National Wildlife Refuge in southern Arizona to study the effects of the boundary wall on wildlife movement, including whether large mammals use open gates during monsoons to cross the border.
The Sky Island Alliance and Wildlands Network are expanding their wildlife research into the US-Mexico borderlands by installing dozens of remote wildlife cameras in June along two miles of the border wall at the small wildlife refuge east of Douglas.
The Sky Island Alliance previously began the Border Wildlife Study in March 2020 with 58 cameras from the mountains of Patagonia across the Huachucas River, including one of the few areas on the Arizona border where there is no border wall.
This new study looks at the San Bernardino Valley, which groups say is an important wildlife migration corridor between the Rocky Mountains and the Sierra Madre Occidental, and which was affected by the 30-foot-high boundary wall.
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While the border barrier cuts off most of the larger wildlife from their migration patterns, animals can still cross the border portion of the year through a series of 1.7-meter-wide flood gates, which open during the monsoon season.
The project’s cameras recorded more than 48,000 images of more than 20 species of mammals during the first month of the study. About 9% of the animals seen near the flood gates crossed through them, including the mountain lion, the bobcat, and the javelina.
It’s too early in the study to say why only 9% of animals use migration gates to migrate, says Eamonn Harrity of the Sky Island Alliance, but one reason may be that it’s a relatively new structure to which animals are still adapting.
If the gates were open year-round, he said, it would give the animals a better chance of getting used to using them.
“If we know that large mammals can cross borders through open flood gates, we can create pathways for wildlife along the US-Mexico border to help them access vital food and water,” he said. “It’s a simple political choice to open these flood gates and help species like mountain lions and black bears find their historical migration routes back through the wall.”
Customs and Border Protection was unable to immediately respond to whether leaving the gates open year-round was a possibility.
There are also many small openings in the boundary wall in that area about the size of a sheet of paper. Harrity says the Sky Island Alliance has seen small animals like the Jackrabbit or Roadrunner use these slots, but animals so small that they could probably fit between the poles in the boundary barrier anyway.
Larger animals such as black bears, mountain lions, and jaguars usually migrate through this border area seasonally in search of breeding mates or for food and water. More than 90% of the critical habitat for jaguars along the US-Mexico border in Arizona is intersected by the border wall.
“The most immediate impact is that for the first time in the history of this continent, in one form or another, there is an impediment to movement,” Harity says. “So these large-scale animals are suddenly cut off from what would otherwise be a seasonally available resource on both sides of the border.”
He said the long-term effect of disrupting annual migration patterns could lead to shrinking animal populations, making them more vulnerable to disease and local extinction events.
This study is some of the only work being done to understand the impact of the Arizona border on wildlife and to look at flood gates to understand their potential as wildlife corridors and wildlife crossing points, Harriet says.
When the wall was built in 2020, the federal government waived all environmental laws using the Real Identity Act of 2005, which, among other things, allows the Secretary of Homeland Security to waive laws to build border infrastructure faster.
No environmental reviews have been conducted to study the impact of the boundary wall on the refuge’s wildlife because all of those laws have been waived, says Michael Dax, program director for the Wildlands Network.
“Now, with this vital research being done, we can begin to understand how the boundary wall affects animals,” he said.
The study has data only up to two months now, but the groups plan to monitor wildlife in the refuge for at least three years, documenting wildlife movement during seasons when the flood gates of the border wall are open and closed.
“I think the long-term effects of this wall would probably be very severe if no measures were taken to increase the openings or the animals’ ability to cross,” Harty said.