Grand Canyon oases face faraway threats
by Anne Minard
HERMIT'S REST, Ariz. - A hike into the Grand Canyon in mid-August is a journey into a world dominated by dust and dryness. Even if you start at 7 a.m. from Hermit's Rest, on the west end of the South Rim, the heat soon becomes stifling. Each step stirs the fine red dirt on the trail, and shadows shrink to become tiny sanctuaries under spindly trees. Beyond the narrow trail, vast white and red rock walls stand in stark contrast to a cloudless blue sky.
But three miles below the rim of the Grand Canyon lies the secret world of Dripping Springs. A miniature garden of moist, green and brown plants clings to an overhanging ledge in the canyon wall. Three separate trickles of water, backlit by the sun, fall silently for 10 feet before splashing into a shaded, rock-rimmed pool. Birds dart in to quench mid-morning thirst, and even during the worst drought in northern Arizona in a century, scarlet monkeyflowers are in full bloom, enticing monarch butterflies.
This oasis is one of hundreds of such islands in the midst of this Southwest desert. Scientists now believe that places like Dripping Springs are part of an interconnected system of springs that trickles from the aquifer underlying all of northern Arizona - one that humans have used for centuries.
If proven true, this theory could have startling implications. While the impacts on springs from livestock and exotic plants have been widely known, scientists are realizing that the springs may be threatened by development as far as 70 miles away, in cities such as Tusayan and Flagstaff. Protecting Southwestern springs could take sweeping changes in the way humans use not just the springs, but water in general.
"Hotspots for biodiversity"
The first step toward protecting springs is understanding them. The Flagstaff-based Grand Canyon Wildlands Council is working to document springs ecosystems on the Arizona Strip - the 8,000-square-mile, mostly BLM-administered area between the Grand Canyon and Utah's border - as well as in Grand Canyon National Park and at the San Francisco Peaks, north of Flagstaff (HCN, 11/22/99: Babbitt looks for support on his home turf).
"Springs take up a tiny, tiny area on the Arizona Strip, but support a huge amount of life," says Bianca Perla, a biologist with the Council. The group has found that 11 percent of the plant species on the Strip occur only at springs. Seventy-five percent of the butterflies in the area rely on the springs, along with a third of the bird species and more than half the land snails.
Larry Stevens, another Wildlands Council biologist, says the springs are "absolute hotspots for biodiversity." Their biological diversity is 100 to 500 times that of surrounding landscapes, he says: "Saving a spring might be equal to saving 10 square miles of land."
For the species that have adapted to live exclusively at springs, these cloistered oases are worlds unto themselves. The endangered Kanab ambersnail, for example, is a relic of more widespread populations that existed before the last ice age. As glaciers receded and former swamps turned to deserts, the snails' habitat became increasingly restricted.
Now, they live at only two places in the Southwest, one of them a well-known spring at Vaseys Paradise in the Grand Canyon (HCN, 7/31/00: The snail that stands like a dam). Ambersnails are called "extreme cases of endemism," meaning they exist at only a small number of isolated places.
But a brightly colored, parasitic flatworm so rare it doesn't even have a common name is even more specialized. Kanab ambersnails eat the eggs of Leucochloridium cyanocittae off leaves, where they're deposited in bird droppings; a single worm can then grow to fill half a snail's body cavity. When the worm is ready to move on, it pushes neon pink and green projections out through the snail's eye sockets and ejects itself to form a ready meal for birds - and continue its life cycle.
"This is a rare parasite, on a rare snail," says Perla. "That's extreme endemism."
Looking beyond the springs
Safeguarding and restoring degraded springs will be a challenge. In Stevens' words, it "remains a rather large sociological experiment."
On private, state and BLM land, he says, many springs are altered by pipes and long-forgotten stock tanks, where some species hang on by using water that drips from the tank sides. There, Stevens and Perla are advocating a mantra of "leave a little" - 20 percent of the original water source is often enough to protect aquatic species.
Even springs protected within national parks and monuments aren't completely safe. "Overall, the biggest problems facing these springs are human visitation and the invasion of exotics," says National Park Service biologist John Spence. The problems go hand in hand: Human visitors inadvertently introduce tamarisk, Russian olive, and exotic thistles, all of which can draw down spring water and outcompete native plants.
Efforts are under way to reduce these threats. At Grand Canyon National Park, a full-time biologist and a couple of volunteers are working to attack the most damaging of 156 species of non-native plants in the park. And at the new Grand Canyon-Parashant National Monument, the nonprofit Conservation Fund recently purchased Pakoon Spring - and another exotic resident, a nine-foot pet alligator - as part of a buyout of a 200-acre ranch.
But the greatest threat may be more difficult to address. Scientists have long believed that the water pouring from the springs comes from a huge aquifer deep underneath northern Arizona. Now, researchers at Grand Canyon National Park and Northern Arizona University in Flagstaff are documenting the chemical composition of springs along the South Rim to determine whether they're impacted by groundwater pumping in Tusayan, Valle, Williams and Flagstaff.
Preliminary results from the chemical composition study should be available by December, but it will still be years before scientists truly understand the springs' relationship with the broader world that overlies the aquifer.
Says Cole Crocker-Bedford, Grand Canyon National Park's chief of natural resources, "Whether it's environmentalists who sound the alarm, or developers who will say we're trying to take away their rights, we owe it to all of them to get the science right."
Anne Minard is a freelance writer based in Flagstaff, Arizona.
You can contact ...
- Grand Canyon Wildlands Council, email@example.com, 928/556-9306;
- John Rihs at Grand Canyon National Park, John_Rihs@nps.gov, 928/638-7905;
- John R. Spence at Glen Canyon National Recreation Area, John_Spence@nps.gov, 928/608-6267.