Border Wall Settlement Presents Significant Opportunity to Study Wildlife Connectivity Between the U.S. and Mexico

Last week, the Sierra Club announced its long-awaited settlement in the case Sierra Club v. Biden, which marks a monumental victory for wildlife and borderland communities impacted by illegal wall construction.

The Trump administration built vast stretches of the border wall with funding illegally transferred from the Department of Defense and Treasury Department in 2019 and 2020. Multiple plaintiffs, including the Sierra Club, Southern Border Communities Coalition, and the ACLU, filed a series of lawsuits challenging the border barriers constructed using these funds. Their successful settlement with the federal government last week sets the stage to begin addressing the harms caused by illegal wall construction along the U.S.-Mexico border.


Customs and Border Protection (CBP) has agreed to stop building wall systems in border areas where the illegal funds were directed and will invest in consultation with borderland communities prior to taking further actions in these areas. To improve wildlife connectivity between the U.S. and Mexico, CBP will install additional openings for wildlife in the border wall, keep a set of flood gates open for two years, and provide funding for environmental restoration along the border. They will also hire wildlife consultants to monitor the efficacy of these actions in a new effort to scientifically understand the impacts of border wall systems on wildlife movement. See the full settlement agreement.

“As two conservation organizations dedicated to studying and championing wildlife connectivity between the U.S. and Mexico, we applaud this significant agreement that invests in conservation science, wildlife crossing structures, and habitat improvements, and which reinstates environmental law and community consultation,” said Michael Dax, western program director for Wildlands Network.

For the past year, Sky Island Alliance and Wildlands Network have been studying wildlife movement along the U.S.-Mexico border in San Bernardino National Wildlife Refuge, where seasonal flood gates have provided an opportunity to compare wildlife movement when the gates are open and when they are closed (per the settlement, these gates will remain open for the next two years). Additionally, Sky Island Alliance has been running a similar study for nearly two years in the San Pedro Valley, where border wall bisects the San Pedro River and adjacent floodplain.

“In both studies, we’ve documented large mammal species like black bears and mule deer forced to walk only east or west when they encounter the border wall because most areas of the wall lack openings large enough for them to use,” said Emily Burns, program director for Sky Island Alliance.” We’ve also seen hopeful evidence that some animals have learned to find and use openings in the wall as they move through the borderlands.”

With more wildlife openings coming to the border wall, more wildlife species in more locations may soon be able to successfully cross.

“Through our study we’ve been able to gain significant insight into how wildlife are interacting with and impacted by the border wall,” said Eamon Harrity, wildlife program manager for Sky Island Alliance. “However, key parts of this settlement will provide important new opportunities to reconnect severed wildlife corridors and learn more about how the border wall can be managed to lessen harm to wildlife and border communities.”

This is a significant moment in border history, and we have immense gratitude for the many organizations and individuals who worked incredibly hard to reach this successful settlement agreement.