Conservation groups have set up cameras at the San Bernardino National Wildlife Refuge in southern Arizona to study the border wall’s impact on wildlife movement, including whether larger mammals use the open floodgates to cross the border during monsoons.
The Sky Island Alliance and Wildlands Network are expanding their wildlife research on the US-Mexico border with dozens of remote wildlife cameras installed along 2 miles of the border wall in the small wildlife sanctuary east of Douglas in June.
The Sky Island Alliance previously launched the Border Wildlife Study in March 2020 using 58 cameras from the mountains of Patagonia through the Huachucas, 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 the groups say is an important corridor for wildlife migration between the Rocky Mountains and the Sierra Madre Occidental, which was affected by the 30-foot border wall.
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While the border barrier cuts off most larger wildlife from their migratory patterns, animals can cross the border part of the year through a series of 1.7 meter wide floodgates that are open during the monsoon season.
The project’s cameras captured more than 48,000 photos of more than 20 species of mammals in the first month of the study. About 9% of the animals seen near the lock gates crossed them, including a mountain lion, a bobcat, and spears.
It’s too early in the study to determine why only 9% of the animals use the sluice gates for migration, but one reason could be that it’s a relatively new structure that the animals have yet to adapt to, says Eamon Harris of the Sky Island Alliance.
If the locks were open year-round, the animals would have a better opportunity to get used to using them, he said.
“If we learn that large mammals can cross the border through open floodgates, we can create wildlife trails along the US-Mexico border so they can access essential food and water,” he said. “It’s a simple political decision to open these floodgates and help species like mountain lions and black bears find their historical migration routes back through the wall.”
Customs and Border Protection could not immediately answer whether it was possible to leave the gates open all year round.
There are also numerous small openings in the border wall in this area, about the size of a sheet of paper. The Sky Island Alliance has seen small animals like a rabbit or a roadrunner use these openings, but only animals so small they would probably fit between the bollards in the boundary barrier anyway, Harrity says.
Larger animals such as black bears, mountain lions and jaguars typically migrated seasonally through this frontier region in search of mates or for food and water. More than 90% of critical jaguar habitat along the US-Mexico border in Arizona has been cut through by the border wall.
“The most immediate impact is that for the first time in the history of this continent, there’s more or less an impediment to movement,” says Harrity. “So these widespread animals are suddenly cut off from a potentially seasonally available resource on either side of the border.”
A longer-term impact of disrupting annual migration patterns could be that animal populations are declining, making them more vulnerable to disease and local extinction events, he said.
This study is one of the only work being done to understand the impact of the Arizona border on wildlife and looking at the floodgates to understand their potential as wildlife corridors and wildlife crossings, Harrity says.
When the Wall was built in 2020, the federal government waived all environmental laws with the REAL ID Act of 2005, which, among other things, allows the Secretary of Homeland Security to waive legislation to expedite construction of border infrastructure.
No environmental assessments were conducted to study the boundary wall’s impact on wildlife at the refuge because all of those laws have been waived, says Michael Dax, program director at Wildlands Network.
“Now that this important research is underway, we can begin to understand how the border wall affects animal populations,” he said.
The study now only has data from a few months, but the groups plan to monitor wildlife at the refuge for at least three years, documenting the movement of wildlife through the seasons when the floodgates of the border walls are both open and closed .
“I think the long-term effects of this wall are potentially quite serious unless action is taken to increase the openings or the ability for animals to cross,” Harrity said.