President Trump signed an executive order on Wednesday pushing ahead one of his signature campaign stumps—the construction of a massive $14-20 billion wall along the 2,000-mile-long border with Mexico, designed to deter illegal immigrants and drugs from entering the United States.
The wall has faced fierce criticisms from human rights groups for the possible humanitarian disaster it could cause (ask Berlin about this). But if built, the wall could pose another threat altogether: ecological disaster.
A barrier would sever animal populations living in the fragile desert ecosystems of the US-Mexico border from food resources, mates, and important migration routes. Such a disruption would deal an irreparable blow to countless species, including extraordinarily rare ones like the Sonoran jaguar and Mexican gray wolf.
Man-made barriers like roads and fences are some of the most devastating types of development to wildlife.
According to a US Fish and Wildlife Service provisional report released last year, a Trump wall covering the entire 2,000-mile border, with approximately 1,000 feet of developed space on either side,would potentially impact 111 endangered species, 108 species of migratory birds, four wildlife refuges and fish hatcheries, and an unknown number of protected wetlands.
Man-made barriers like roads and fences are some of the most devastating types of development to wildlife. Ecosystems are fluid, with animals flowing through them regularly. And obstacles like roads and fences put a stranglehold on individual populations, cutting them off from food resources, or outright killing them.
The US-Mexico border transects an array of environments including two highly unique and biodiverse ecosystems: the Rio Grande Valley in Texas, and the Sky Islands in the southwest. The Rio Grande Valley is one of the most biodiverse places in North America, with some 700 species of vertebrates alone, and rakes in $463 million a year from wildlife watchers, like birders, who come to witness thousands of birds flying through on great migrations. Bobcats, javelinas, ocelots, deer, some 500 species of migratory birds, and scores of amphibians and reptiles all depend upon free movement through this region.
We can predict the damage a Trump wall will cause based on some portions of the border that serve the same purpose now. A menagerie of barbed wire and 18-foot-tall steel fencing is intermittently scattered across 650 miles of the border from California to Texas, part of a project that came to fruition in 2005, during the George W. Bush years. By 2011, range for some 16 species had fallen by as much as 75 percent. Some extremely rare species like ocelots in Texas (there are only about 50 in the US), were completely cut off from their more diverse Mexican counterparts—leading to a loss of genetic diversity. Bison have been spotted climbing over barbed wire fencing trying to get to food and water.
Louise Misztal, biologist and executive director of conservation non-profit Sky Island Alliance in Arizona, told me on the phone that "What's interesting about the infrastructure that's already on the border is that it really affects all species. Anything from a bear that has no chance of getting through, even down to little frogs and toads. It's impassable even to small wildlife."
In southwestern US and northwestern Mexico, a particularly unique wildlife corridor where the ends of the Sierra Madres and Rocky mountains meet, tropical species like the jaguar and ocelot from northwest Mexico link with species like the bears and mountain lions from southern Arizona.
"Wide ranging mammals like mountain lions, bears, jaguars, ocelots, need to be moving between these different mountain ranges to get to food resources and water," said Misztal.
"There's a bigger picture of movement that we need to keep in mind."
A Trump wall would block "pioneering" jaguars from migrating into the United States and repopulating the area. The wall would also sever the tiny population of 100 or so Mexican wolves in two—the most endangered subspecies of gray wolf in the world. Aside from these immediate impacts, a full-length border wall would also stop species from being able to change their locales and lifestyles in order to adapt to a changing climate.
"With climate change, a lot of species are moving around, some species are extending their ranges north," said Misztal. "So there's a bigger picture of movement that we need to keep in mind."
Flying animals like birds and insects won't be able to simply soar above the great wall, either. If the barrier is lit, migrating flying creatures—birds and insects alike—could be thrown off course, their star-based navigation jammed. The walls currently standing along portions of the border have also already damaged waterways, which disrupts migratory birds, said Misztal.
The deeper, ecological impacts from a loss of species and the services they provide remain unclear and could be far reaching. "In addition to the really obvious and visible wildlife impacts there may be long term impacts that we're not able to see right now," remarked Misztal.
The Department of Homeland Security, however, is waived from environmental regulations when building security infrastructure, so this will likely not be taken into account. The project is still likely to face countless obstacles though, including engineering problems, and fights with ranchers and other locals who refuse to give up their land.
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