Construction vs. Conservation: Threatening Wildlife to Build a Wall

Stori Smith

Stori Smith

Senior Staff Writer for SAFE Worldwide

Extended across the continent from the Gulf of Mexico to the Pacific Ocean is 2,000 miles of division. On one side, you are Mexican. On the other, American. But rather than a mere line that determines legality and splits our allegiances, can we also appreciate this stretch of earth stitches North America together? Our U.S.-Mexico border is an area of environmental overlap. Temperate, desert, coastal, and sub-tropical climates converge to create one of the continent’s most unique landscapes. Forests, grasslands, salt marshes, rivers, and mountains provide habitat to more than 1,500 native species. Ecologists say we have a “global responsibility” to safeguard this biodiversity hotspot.

Instead, we bulldozed it.

Big, but Not Beautiful

Former President Donald Trump called the southern border wall his “big, beautiful wall.” What about the big, beautiful wilderness that, after explosions and excavation, will not recover? What about the wildlife? In all the border wall debates, where are the birds, more than 500 species strong? How about 40% of our country’s butterfly population? The endangered aquatic species? Where is the outcry that an ocelot—whose population already shudders on the endangered species list—travels across its territory to find its corridor cut down from hundreds of miles to four inches?

Along with deer, bighorn sheep, antelope, javelinas, bobcats, mountain lions, and wolves, it can only stare through the spaces between steel posts extending two stories toward the sky at the land it can no longer call home.

Even now, with Joe Biden and his presidential promise to halt border wall construction, those of us who support wildlife must remain vigilant. We must face the damage that has already been done and ensure President Biden and future administrations do not resume construction. Because, while much of the southern barrier’s future is still uncertain, one part isn’t. The wall, marketed as an American lifesaver, is guaranteed to push many species, who have used these migrating corridors for thousands of years, to the brink of extinction.

Land Already Lost

The borderlands—in their natural state—are valuable, as evidenced by the United States Fish and Wildlife Service’s (USFWS) 41-year effort to purchase land along the border to spare it from farming and development. These purchases were called “a string of pearls,” little pockets of treasured preservation. During Trump’s presidency, the USFWS continued to acquire more tracts of land for this project but also for President Trump’s promised wall between the United States and Mexico. In 2019, President Trump declared a national emergency at the border. While this secured funding for the wall, the government needed more land for building. Since gaining access to privately owned borderland took time and negotiations, the Trump administration rushed construction through plots already in federal possession, gradually turning portions of our string of pearls into steel blockades. Congress previously shot down funding to build in the Roosevelt Reservation but with the emergency declaration, that, along with 41 federal laws, flew out the window. The Department of Homeland security could bypass essentially any environmental law in its way.

The Clean Air Act.

The Endangered Species Act.

The National Environmental Policy Act (NEPA).

All dismissed.

A Customs and Border Patrol official claims the agency “conducts all necessary research and surveys to include environmental clearances…and avoid or mitigate potential impacts to sensitive locations” (Falk, 2019). But if it is allowed to disregard NEPA, which requires comprehensive environmental evaluations for large federal projects, what incentive does the agency have to stall construction for wildlife assessments? In fact, in 2020, wall construction only became sloppier with workers rushing around the clock and across the wilderness, to put up 450 miles of wall before the end of Trump’s presidency. With dynamite and bulldozers, they accomplished their goal, obstructing one-fifth of border ecosystems with 30-foot barriers and their accompanying roads, lights, and bases for operation.

Lives At Risk

Such intrusive construction wipes out, or at least damages, plant life and can directly kill some animals. It also leaves a legacy of destruction that will continue to disrupt wildlife populations. Reduced habitat, increased fragmentation, and reduced connectivity each exacerbate each other’s detrimental effects. Habitat loss alone leaves animals with less area, and therefore fewer resources. Habitat fragmentation means that reduced available area is split into separate segments, and wildlife populations may become isolated to the plot they were on before wall construction started. Reduced habitat connectivity ensures this with its reduction in safe corridors between habitat segments. Even if suitable habitat is still available beyond the wall, many animals cannot reach it. Altogether, the wall’s habitat impacts will likely decrease local wildlife’s genetic diversity, alter migration routes, and cut off access to food and water. Of the nearly 350 nonflying U.S. species researchers analyzed, more than 34% could lose access to half their range and 17% may face extinction if a continuous barrier is constructed along the southern border. Even low-flying butterfly and owl species may be affected by the wall.

To present the barrier as less threatening than it is, some invested in its construction classify it as a fence not a wall. But if animals can’t fit through the barrier’s 4-inch slits, it doesn’t matter what it’s called. Rhetoric won’t save them.

Peninsular Bighorn Sheep

(Ovis canadensis nelsoni)


Peninsular bighorn sheep require large ranges with a lower population density per square mile. Therefore, habitat degradation due to wall construction could lead to population decline and even complete loss in some areas. This, in turn, decreases genetic diversity. Considering disease transmission is one of their main threats, this could leave bighorn sheep in an exceptionally precarious survival situation. Researchers also worry a large barrier may restrict their ability to respond to shifts in suitable habitat due to climate change, leaving them increasingly vulnerable to another massive human disturbance.


(Leopardus pardalis)


Human development, along with poaching and poisoning, have long plagued ocelot populations. Their migration routes are already altered, and inbreeding is rampant. A continuous wall would destroy the possibility of reconnection among isolated populations and may set the wild cat on an inevitable, and short, path to extinction.

Mexican Gray Wolf

(Canis lupus baileyi)


Mexican gray wolves, also known as lobos, are the most distinct and threatened gray wolf subspecies due to previous persecution. The United States and Mexico are currently working together to reestablish populations in Arizona, New Mexico, and Mexico, but a border wall would prevent released wolves from dispersing across their historical habitat and prevent current small wild populations from growing. Wolves are a keystone species, so restricting Mexican gray wolf recovery damages their entire ecosystem.

There are more.

These are only three of the southern border’s many species whose population projections crumble with each segment of wall construction. A Customs and Border Patrol Council member questions whether there is enough research to worry about the wall wiping out entire species. But rather than warrant the dismissal of a potential blow to wildlife populations, this lack of research reveals the recklessness of “forcing an unplanned experiment” on sensitive natural areas (Burnett, 2020). Ecologists warn endangered species may become “zombie species” that are not immediately killed but are “demographically and genetically doomed” (Jordan, 2018). Bighorn sheep, large predators, even small aquatic creatures, are all at risk.

If construction continues, at what point will the south’s steel posts become less like boundary markers and more like tombstones in a cemetery haunted by biodiversity’s ghosts?

Looking Ahead

Fortunately, for now, construction is not continuing. On his first day in office, President Biden ended the national emergency at the border, paused wall construction, ordered a 60-day review of the project, and requested a plan to reroute remaining wall funding. As of April 2021, however, the review was still ongoing, and the Biden administration has yet to announce any clear updates. Smaller construction projects may resume to fill in gaps and gates, but President Biden’s first budget proposal does not mention wall construction funding, which many consider a good sign for the border.

In this period of paused construction, ecologists and wildlife advocates are doing damage control, prioritizing restoration of especially sensitive areas and wildlife corridors with requests as ambitious as tearing down portions of the wall blocking critical corridors. If construction resumes, conservationists want more planning devoted to animal impacts. The Department of Homeland Security needs to research and release a detailed risk assessment for borderland species, habitats, and resources. Construction plans should account for as much wildlife movement as possible, and, for each segment of land where ecosystem destruction cannot be avoided, a similar segment of habitat elsewhere should be promised protection.

An International Emergency

In 2018, a study calling for the Department of Homeland Security to revise its wall project strategies in the name of conservation was published with thousands of scientists’ endorsement signatures. Politicians in power brushed it aside like the 41 environmental protection laws they dismissed less than a year later. United States citizens must speak up. We cannot bask in the hope of Biden’s administration and forget about the 452-mile shadow on the border. There are still about 300 more miles of incomplete yet contracted land for the wall. While some lawmakers suggest redirecting wall funds to technological border security measures, some GOP leaders insist existing funds can only go to the wall as initially intended. As we look toward future elections, don’t forget to look south. We must demand our elected leaders and national conservation groups, like the USFWS, include wildlife in their decision-making and that leaders realize wall construction’s destruction. Even some border town mayors are unaware of the bulldozing of biodiversity just outside their city limits.

Biodiversity loss is a national—nay, international—emergency that wall construction only worsens. If we don’t erase the image of a continuous southern border from American policymakers’ plans, we risk building an impassable barrier with irreversible damage. Borderland wildlife lives not according to country but ecosystems extending past our legislative lines. Instead of blocking them, let us block southern destruction, standing together with pillars of strength instead of steel, to ensure what remains of North American landscapes may remain intact rather than destructed in the name of so-called safety.

Organizations Supporting Borderland Wildlife

Cuenca Los Ojos

National Wildlife Refuge Association

Center for Biological Diversity

Drone Footage of Wall Construction

John Kurc Youtube 

Featured Image

Featured Image: © Tomas Castelazo, / Wikimedia Commons / CC BY-SA 4.0


Burnett, John. “Border Wall Rising in Arizona, Raises Concerns Among Conservationists, Native Tribes.” NPR, 13 Oct. 2019, 

Burnett, John. “Contractors Dynamite Mountains, Bulldoze Desert in Race to Build Trump’s Border Wall.” NPR, 11 Dec. 2020, 

Burnett, John. “With Border Wall Construction Finally on Hold, Activists Worry About What’s Next.” NPR, 01 Feb. 2021, 

Burnett, John & Marisa Peñaloza. “Border Wall Threatens National Wildlife Refuge That’s Been 40 Years in the Making.” NPR, 14 Jan. 2020, 

Donnella, Leah. “The Environmental Consequences of a Wall on the U.S.-Mexico Border.” NPR, 17 Feb. 2017,  

Falk, Mallory. “Critics Say Border Wall Could Harm Wildlife Corridors and Sensitive Desert Terrain.” NPR, 21 Feb. 2019,

Jordan, Rob. “How would a border wall affect wildlife?” Stanford Earth Matters, 24 July 2018, 

Montanaro, Domenico. “100 Days: How Biden Has Fared So Far On His Promises.” NPR, 26 April 2021, 

Peters, Robert, et al. “Nature Divided, Scientists United: US-Mexico Border Wall Threatens Biodiversity and Binational Conservation.” BioScience, vol. 68, no. 10, 24 July 2018, 

Schwartz, Jeremy. “Cartels, cars, politics — and now a wall? Ocelot’s threats multiplying.” Daily Hampshire Gazette, 10 April 2018,–and-now-a-wall-Ocelot-s-threats-multiplying-16777540 

Siegel, Benjamin. “After pledging not to build up Trump’s border wall, Biden’s intentions remain unclear.” ABC News, 20 April 2021,

Disclaimer: The opinions, beliefs and viewpoints expressed by the various authors and forum participants on this web site are their own and do not necessarily reflect the opinions, beliefs and viewpoints of SAFE Worldwide.

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