Make one of your New Year’s resolutions to visit at least one national monument outside of California in 2011. I suggest you consider visiting the artifacts of the Ancestral Pueblo Peoples of Chaco Canyon, or the intriguing petroglyphs of West Mesa, or the great wave-like dunes of gypsum sand — all located in the sparsely inhabited state of New Mexico.
South-central New Mexico is home to the San Andres Mountains and the most immense white sands desert on the planet. At White Sands National Monument the dunes play tricks with your mind — distances deceive and the bareness is totally surreal. The white sands are located in North America’s largest desert called the Chihuahaun Desert. It is the least known of the big four deserts because more than 80 percent of it occurs in Mexico.
Summers are searing with daytime temperatures exceeding 100 degrees and winters are cold with freezing temperatures some nights. The lion’s share of the precipitation occurs in July, August and September from monsoonal thunderstorms generated by the Gulf of Mexico.
The dunes of White Sands Monument are unique, in fact they make up the largest gypsum sand dunes on the planet. Most of the world’s sand is made up of quartz — a hard silicon material. Gypsum is made up of calcium and sulfur atoms.
Between 24,000 and 12,000 years ago, rain and snow melt from the peaks of the San Andreas Mountains dissolved gypsum (calcium sulfate), salt (sodium chloride) and Epsom salt (magnesium sulfate) and carried it into the valley bottom where it formed a 772 square mile lake called Lake Otero. Millions of tons of dissolved gypsum, silt and clay were washed from the mountains into the lake, which dried up 4,000 years ago. Once Lake Otero completely evaporated, the lake-bed left behind was salty or alkaline. Beneath the clay and silt gypsum was locked into a crystal form, called selenite, waiting for the wind. Strong southwesterly winds picked up clay and silt particles carrying them high into the atmosphere and out of the area.
The freezing, thawing and sand blasting by the winds broke selenite crystals into white sands particles. As more crystals were disintegrated more gypsum sand began to accumulate and the white sands of this exquisite monument were created.
Forty percent of 185 square miles of the dunes are actually in the national monument, while the rest of the dunes are located in White Sands Missile Range.
The winds are always at least light here out of the south, east or west. In the springtime this desert is raked by extremely strong southwesterlies with average wind speeds in March and April of 47 mph.
There are at least three kinds of dunes. Barchan or crescent dunes look like a ram’s horn and can reach a height of 66 feet. They accumulate in areas with limited sand. Transverse dunes occur where there’s lots of sand and resemble a wave on a lake. Both types of dunes can move 13 feet a year.
Parabolic dunes have arms like Barchan’s but occur upwind rather than down wind so the direction of their arms is reversed. The move only 6 feet a year and occur on the eastern edge of the monument.
Far from being void of plants and animals White Sands is brimming with life.
Soaptree yuccas cope with shifting dunes by growing higher or outgrowing the encroaching sea of gypsum. They are also able to grow new shoots from their existing root system.
Yucca flowers have a special mutualistic relationship with the Pronuba moth, which visit at night, gather pollen and assist with cross-pollinating the yucca plants. In return, the moth lays her eggs in the developing ovary of the yucca flower. She deposits one egg in a seed but is careful not to disturb every yucca seed because she needs the plants to perpetuate; they are the moth’s only food source.
There are 76 animal species and over 100 families of insects here. Some of them rely on camouflage, or more specifically white coloration, in order to live here.
The Cowles prairie lizard is normally black but it would stick out like a sore thumb in a white desert, so it adapted and it’s white. Cowles spadefoot toads and camel crickets have also specially adapted with white coloration.
Spadefoots are the largest native toads in the U.S. measuring a whopping 7 inches in length.
These incredible animals sleep for almost one year in the earth. The vibrations of the first summer thunderstorm awaken them and they burrow their way to the surface where they congregate in temporary rain pools and puddles in the desert.
Because water is so scare in the desert they breed immediately and females lay eggs within 24 hours. Tadpoles must race to become toadlets before the ephemeral pools dry-up — from egg to toadlet in less than 14 days.
Adult Spadefoot’s are insectivores with termites being their preferred prey. An adult requires just two meals on termites, then with their hard keratinous spade-like pad on their hind legs they bury themselves in the ground. This exceptional desert dweller can live for over 10 years.
This unique White Sands desert and many other treasures of New Mexico in “The Land of Enchantment” are very worthy of exploration this springtime.
Dr. Reese Halter is a Science Communicator: Voice for Ecology, conservation biologist at Cal Lutheran University and public speaker. His latest children’s book is “Mysteries of the redwood Forest with Bruni the Bear.” Contact him through www.DrReese.com
