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Border wall threatens birding sites; scientists speak out

A border wall could affect two of the best places to see Altamira Oriole in the U.S.: the National Butterfly Center and Bentsen-Rio Grande Valley State Park. Photo by Tim Zurowski/Shutterstock

Pressure from birders and environmental groups in 2017 spurred Congress to exempt building a border wall through Santa Ana National Wildlife Refuge in South Texas, but the current federal budget allows barriers to be built in the region that would cut off or diminish 16 other refuge tracts, state properties, county parks, and nonprofit nature sites. In all, the loss of natural areas could total more than 6,500 acres, according to the Save Santa Ana advocacy group.

Plans from U.S. Customs and Border Patrol show that nearly all of Bentsen-Rio Grande Valley State Park and 70 percent of the National Butterfly Center would be cut off behind a potential wall. No fewer than 345 bird species have been tallied in the park, and the butterfly center has a bird list of more than 275 species. Several tracts of the Lower Rio Grande Valley National Wildlife Refuge could also be lost, as well as 96-acre Anzalduas County Park.

CBP recently sent letters to property owners along the Rio Grande saying current proposals call for a concrete levee wall with 18-foot steel bollards sitting atop the structure. The project would also include LED lighting, a camera surveillance system, and a 150-foot zone on the south side of the wall where only property owners and law enforcement will be allowed.

Meanwhile, this week, more than 2,700 scientists from around the world endorsed a paper published in BioScience that shows that a continuous wall on the border between the United States and Mexico would harm a multitude of animal species by fragmenting their geographic ranges.

“Our analysis shows that the border bisects the geographic ranges of 1506 native terrestrial and freshwater animal (n = 1077) and plant (n = 429) species,” say the authors, noting that the number includes 62 species already listed as Critically Endangered, Endangered, or Vulnerable by the International Union for Conservation of Nature.


The paper describes three ways the border wall and other security measures would threaten biodiversity: by not adhering to environmental laws, eliminating and fragmenting animal and plant populations and habitats, and devaluing binational research and conservation investments.

The lead authors, including Robert Peters, of Defenders of Wildlife, and William J. Ripple, of Oregon State University, point out that, “Border barriers could also hinder some low-flying species, like the ESA-listed Endangered Quino checkerspot butterfly and the ESA-candidate Ferruginous Pygmy-Owl. Over long periods, degradation of landscape connectivity can also drive genetic discontinuities in plants and animals. Although the influence of barriers on populations depends on both a species’ movement ability and the quantity, quality, and spatial arrangement of habitats, for many species the biological impacts of a ‘wall’ are comparable to those of a ‘fence.’ What matters is whether the barrier is passable, and from a jaguar’s point of view, an uncrossable fence has the same effect as a wall.”

Visit to view the updated list of signatories and to sign it. — Matt Mendenhall, Editor

Scientists update their ‘warning to humanity’ on its 25th anniversary


Save Santa Ana Facebook page

Post updated on July 28 with a more accurate total for the bird list of the National Butterfly Center.


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