The Chisos Mountains loom as an island rising above an arid Chihuahuan Desert.
To feed the miners, Anglos and Mexicans set up irrigated farms near Boquillas, along Castolon valley, and at Terlingua Abaja. These activities took an enormous toll on Big Bend’s natural resources. Woodsmen scoured the country far and wide for timber for buildings and for firing mine furnaces. Ore train mules fed heavily on the chino grama grass. And when the mines failed and the farmers abandoned their fields, they left the land so bare that much time went by before the desert shrubs began taking over.
Ranching did not really come to Big Bend until after the Indian Wars. But once surveying parties began to locate and survey sections, cattle, sheep, goats, and horses came by trail and rail to feed upon the virgin grasslands. First-comers took up lands with permanent water; from the earliest days ranchmen headquartered at Oak Spring in the Chisos. Later arrivals had to dig wells and install windmills as Sam Nail did at the Old Ranch. The 1930s saw the end of “open range” ranching, and fencing became a prime concern for such ranchers as the Burnhams at Government Spring and Homer Wilson in the Chisos. Other ever-present problems involved water resources, drought, livestock losses from disease and predators, and remoteness from markets, schools, and doctors. Most ranchers understood the land and many loved it. They used their pastures to capacity, but they did not overstock the range until the 1940s. Then, just before the national park came into being, ruinous overgrazing all but wiped out the grasslands.
Today, Big Bend National Park sprawls across 3,205 square kilometers (1,252 square miles) inside the southernmost tip of the Bend. Even with interstate highways, park headquarters is a long way off. It is 660 kilometers (410 miles) from San Antonio to Panther Junction, 520 kilometers (323 miles) from El Paso, 173 kilometers (108 miles) from Alpine’s meals and motels, 110 kilometers (68 miles) from the last community, Marathon. But the journey is well worth the effort, because the park preserves some of the nation’s most dramatic land forms and rarest life forms.
The main body of the park is a great 65-kilometer (40-mile) wide trough or “sunken block” that began to subside millions of years ago, when Mesa de Anguila and Sierra del Carmen cracked off and slowly tilted up to the west and east. The Rio Grande draws the park’s southern boundary, slicing through three mountain ranges to form Santa Elena, Mariscal, and Boquillas Canyons. And right in the middle of the sunken block, rising higher than all the other mountains, the Chisos hang above the desert like a blue mirage.
Mule deer graze along the Grapevine Hills Road. As climate continues drying here, these denizens of the desert range ever higher into the Chisos Mountains, sole homeland in the United States for the Sierra del Carmen whitetail deer.
A gnarled alligator juniper suggests the timeworn landscape spread below the South Rim of the Chisos.
What makes a desert, of course, is scanty precipitation. And because of the great range in altitude—from 550 meters (1,800 feet) along the river to 2,400 meters (7,800 feet) atop the Chisos—there is a wide variation in available moisture and in temperature throughout the park. This has produced an exceptional diversity in plant and animal habitats. Receiving less than 25 centimeters (10 inches) of rainfall in a year, almost half the park is shrub desert. This plant community begins right next to the river and runs on up to about 1,050 meters (3,500 feet). Another 49 percent of the park is desert grassland, a somewhat less dry environment that you will encounter on mesa tops and foothills to about 1,700 meters (5,500 feet). From there on up, mountain canyons and slopes may sustain typical southwestern woodlands with pinyons, junipers, and oak trees. The Chisos heights receive some 46 centimeters (18 inches) of rain per year and are considerably cooler than the desert. Consequently you will even find 325 hectares (800 acres) of forest in two or three high canyons, where towering Rocky Mountain-type trees persist from cooler, moister times. And that is not all: A lush green jungle grows in a narrow belt along each bank of the Rio Grande and pushes out across the desert along creeks and arroyos. And in the river itself live creatures you wouldn’t expect to find in the middle of the desert!