Ask Americans about the pedestrian fencing and vehicle barriers along the Mexican border and brace yourself for a torrent of opinion. Some will say they’re necessary; others will say they’re ugly. Some will say they’re an effort to stem massive law breaking; others will say they’re symbols of an immigration system in collapse.
Few will say they benefit the environment.
But, in important ways, they’re doing just that.
The best laboratory to judge their impact is heavily-crossed Arizona, with its vast tracts of federally-managed borderland. These desert and mountain ecosystems are unique in the world, and extremely fragile. They’re also remote and sparsely populated, making them ideal smuggler terrain.
After a multi-year planning and construction effort, opposed by powerful environmental groups such as the Sierra Club, vehicle barriers now block most of the land where these preserves meet Mexico. The result has been a significant drop in the number of destructive smuggler drive-throughs.
A good example is southern Arizona’s Coronado National Forest, which has Normandy-style barriers on its border land, excluding the mountainous areas.
“The smugglers have a much harder time driving their loads in and that has benefited the land,” says Keith Graves, a former district ranger for the Coronado. “We’re not seeing the kind of damage we used to see.”
The same has occurred at the 330,000-acre Organ Pipe Cactus National Monument southwest of Tucson, where Manager Lee Baiza calls its rail-on-post barriers the best investment the Department of Interior has made in a long time.
In addition to making it tougher to drive across the border, the barriers have reduced the number of southbound chases. In these episodes, smugglers spotted by law enforcement would turn around and flee, tearing up the desert as they escaped back into Mexico through the old wire fence.
At the 118,000-acre Buenos Aires National Wildlife Refuge — where vehicle barriers were installed in 2006 and replaced by a four-and-a-half-mile pedestrian fence in 2008 — vehicle crossings have been virtually eliminated, says spokesperson Bonnie Swarbrick.
The Buenos Aires is one of the few federal preserves with a significant stretch of pedestrian fencing, which most land managers reject as too intrusive. Unlike vehicle barriers, an impassable wall can alter the migration of animals, some endangered, possibly blocking their access to key habitat on both sides of the border.
In areas where pedestrian fencing does stand — Arizona now has 124 miles of it and 183 miles of vehicle barriers — ranchers and landowners report improving conditions on the fence’s north side — less ground trampled by people and grazing Mexican cows, less trash to poison animals and foul water supplies, and fewer foot trails and wildcat roads.
Both can cause serious erosion. If used often enough, they denude the ground of vegetation and compact the soil, allowing water runoff to make gullies that can form their own streams.
Roads provide paths for predators to move into new areas to feast on prey species, throwing animal populations out of balance. A smuggler also has no concern for the archaeological sites he’s rolling over or the endangered plant species he might be damaging.
And to avoid detection, he necessarily drives through the most rugged terrain, which means the vehicles often break down, becoming litter. Land managers find big pickup trucks upside down in stream beds, leaking gas fouling the water supply.
The number of abandoned vehicles at Buenos Aires stood at 100 a few years ago. Today, there’s one remaining with no new ones arriving, says Swarbrick.