Dunes Sagebrush Lizard
Dunes Sagebrush Lizard
Scientific Name: Sceloporus arenicolus
Range: approximately 1200 square miles in southeastern New Mexico and western Texas
Conservation Status: Proposed for listing as “endangered” (December 2010)
Remaining Population: Unknown
Threat: The dunes sagebrush lizard is found only in rare shinnery oak-sand dune habitat in southeast New Mexico and western Texas. The lizard has one of the smallest distributions of any lizard in North America. Its narrow range is threatened by extensive oil and gas development in the Permian Basin, which destroys and fragments its habitat.
Skittering amidst spare stands of shinnery oaks and over the scorched sand hills of the Permian Basin, the dunes sagebrush lizard makes its home. The silence and stillness of this land, which befits the incredibly sensitive nerves of this perpetually alert dunes crawler has become noisier than ever with the grinding hum of oil and gas wells and compressors.
An insatiable insectivore—eating ants, small beetles, crickets, grasshoppers, and spiders—and prey of local vipers, the dunes lizard relies on its skittish speed for survival. Incredibly attuned to this harsh landscape, the lizard depends on the shinnery oak—a small, three-to-five foot tree with an extensive root system—for shelter and cover from predators. The dunes sagebrush lizard is so particular about its quarters that even the size of the granules of sand around the base of a shinnery oak impact its decision to stay. It lives in wind-hollowed depressions in sand “blow-outs” within the dunes that are generally a little over 300 cm deep and around 30 meters long.
In extreme southeast New Mexico and west Texas, these oaks are often the only vegetation on the horizon. Their increasing sparsity and the proliferation of oil wells on the landscape is responsible for the decline of the lizard’s slim, crescent-shaped range to nearly half of what it was in 1982.
Threats Due To Fossil Fuel Development
Oil and gas extraction is the primary threat to the dunes sagebrush lizard and its habitat. The Permian Basin, at 75,000 square miles, is the largest onshore oil field in the United States. Oil companies have drilled tens of thousands of oil and gas wells in the region, including thousands of wells in lizard range. Unfortunately, this lizard is extremely sensitive to habitat disturbance. A single well can reduce its population by almost 50 percent in the surrounding 250 meters. Densities of 30 wells per square mile would reduce lizard populations by 50 percent. Disturbance from well pads, effects from leaking pipelines, and high concentrations of toxic hydrogen sulfide gas emitted from wells all contribute to the decline of sand dune lizard populations.
In 2001, the U.S. Fish and Wildlife Service (FWS) made the lizard a candidate for listing under the Endangered Species Act because it faced “high magnitude, imminent ” threats to its survival, especially from oil and gas drilling. In December 2010, FWS proposed the species for listing as “endangered,” noting the lizard’s continued decline despite the species’ conservation plans.
Unfortunately, Congressional opponents have loudly proclaimed that listing will “shut down” oil and gas development in the Permian Basin. Representative Steve Pearce (R-NM-2nd) and colleagues have tried every conceivable tactic to prevent FWS from protecting the species. Pearce’s opposition to listing the lizard is without basis, however, as the dunes sagebrush lizard occurs on less than 2 percent of the Permian Basin, and even its tiny range has been drilled with thousands of oil and gas wells. FWS has repeatedly stated that listing the lizard will have negligible effects on oil and gas development—but Pearce and his colleagues are undeterred. He and other members of Congress recently pressured FWS to delay the final listing decision for six months, allowing opponents more time to sharpen their attacks on this tiny reptile.