The San Bernardino Valley, straddling Arizona and Mexico, is a hot spot for bee diversity—but faces unknown impacts from the "trump border wall" construction.
A group of solitary bees known as Svastra duplocincta. Males of this species gather together at night to roost and sleep upon plants, grasping them with their mandibles so they don’t fall off. PHOTOGRAPH BY BRUCE D TAUBERT
Excerpt from this story from National Geographic:
In the midst of the Chihuahuan Desert, straddling the border of southeastern Arizona and Sonora, Mexico, the San Bernardino Valley is an oasis of life. Following rains, especially the monsoon downpours of late summer, the area explodes with an abundance of flowers—and a bevy of bees. In fact, research by entomologist Bob Minckley shows that this area has the highest concentration of bee species in the world.
In a recent paper published in the Journal of Hymenoptera Research, Minckley and San Bernardino National Wildlife Refuge manager Bill Radke found that 497 species of bees live within just over six square miles of the valley, a modest area for such a study, 10 times smaller than Washington D.C.
To put that in context, these 497 species represent 14 percent of all the nearly 4,000 bee species found in the United States—and that’s more than are found in all of New York state (and most other states), he adds.
This valley is fed by fossil water, which over thousands of years seeps south from the Chiricahua Mountains to feed gushing artesian wells, filling ponds and creeks lined with cottonwood trees and hundreds of varieties of flowering plants. Large creatures such as mountain lions, bobcats, javelina, and other mammals roam the land—and birders often visit to see some of the rare species that fly through. The Arizona side is made up of San Bernardino National Wildlife Refuge, and in Sonora, much of the valley is owned by Cuenca Los Ojos, a binational conservation organization.
This hot spot of bee diversity faces several threats. In 2020, the Trump Administration built 30-foot-high steel fencing along the entire border of San Bernardino National Wildlife Refuge, part of the 200-plus miles of border wall put up in Arizona alone. (Learn more: Sacred Arizona spring drying up as border wall construction continues.)
The wall’s construction caused an immediate and sustained reduction in the movement of animals, according to preliminary data from a series of camera traps, Traphagen says. But the most ecologically damaging aspect may be the massive quantities of water withdrawn from the refuge’s aquifer to make concrete for the base of the wall. After groundwater pumping began, several ponds went dry, leading to a state of emergency at the refuge in which staff had to relocate endangered fish, and install artificial pumps to keep ponds full. These small water bodies are home to eight species of rare desert fish, four of them endangered and found nowhere else in the United States.
