October 12, 2008

Endangered Status Sought for Sonoran Desert Tortoise



Two environmental groups are pushing the federal government to list the Sonoran Desert tortoise as an endangered or threatened species.

This morning, the groups Wild Earth Guardians and Western Watersheds Project will take legal action to try to force the U.S. Fish and Wildlife Service to protect the tortoise, which lives in a large swath of Arizona, from Tucson to the state's far northwest corner. The groups will file a petition that often leads to lawsuits.


THE ACTIVISTS: Wild Earth Guardians, based in Santa Fe, tries to preserve forests, rivers, deserts and endangered wildlife by opposing urban expansion, grazing, mining and timber cutting. Western Watersheds Project is an Idaho-based group that tries to preserve and restore public lands in eight Western states, mainly by focusing on what it says are harmful effects of livestock grazing.

THEIR REASONING: The tortoise's population has dropped 51 percent in Arizona since 1987, says a new study that analyzed data from 17 tortoise study plots. The groups commissioned the study from two California biologists.

THE CULPRITS THEY SEE: Causes of the tortoise decline include urban sprawl, cattle grazing, disease, drought, mining, federal projects such as roads, drainage ditches and irrigation diversion projects, and motor vehicles driven by illegal immigrants and the U.S. Border Patrol, the groups say.

Drought is also a key concern, said Phil Rosen, a University of Arizona reptile specialist. "It would appear that the drought's effects are exacerbated by high temperatures," Rosen said. "It's possible there may be direct effects of high temperature on tortoises."

WHY THE TORTOISE MATTERS: Its health is linked to that of the broader Sonoran Desert, activists say. As eaters of grass and other plants, tortoises process materials that wouldn't be used by other wild animals. They serve as food for predators such as skunks, foxes, coyotes and ravens.

HOW POPULAR IS THE TORTOISE?: Thousands of Tucsonans have adopted tortoises over the last 20 years through an Arizona-Sonora Desert Museum program. The animals are charismatic and charming, said Cindy Wicker, an East Side resident who has had an adopted tortoise for a decade and worked 15 years as a volunteer with the museum program.

"It's hard not to smile when you see a tortoise. They are just very disarming," Wicker said.

THE SCIENCE: The new study doesn't prove that the entire state's tortoise population is declining, said Taylor Edwards, a University of Arizona biologist who is president of the Tucson Herpetological Society and has studied tortoises. Because the study plots weren't randomly chosen, they don't represent the entire population, he said.

The lack of randomness weakens but doesn't negate the conclusions that can be drawn, countered William J. Boarman, one of the study's authors. The 17 sites represent habitats where most Arizona tortoises live, and "most importantly, these are the only data available to look at long-term population trends in these tortoises."

WHO GETS HURT: If the tortoise is federally listed for protection, restrictions could be placed on home-building. That, in turn, leads to higher home prices, builders have said when other urban species were listed.

Protection could also lead to restrictions on grazing, mining and various federal projects, as well as electricity generation and gasoline use that are linked to greenhouse-gas emissions.

THE PROS: Federal land managers will never do enough to protect the animal without the legal clout of a federal listing, supporters of the legal action say. Since the Fish and Wildlife Service turned down another group's request to protect the tortoise in 1991, "We're pleading with them now to act before it's too late," said Nicole Rosmarino of Wild Earth Guardians. "The trends are very bleak. The tortoise is perennially facing death by 1,000 cuts."

THE CONS: Opponents say these groups' real agenda is not protecting species, but stopping activities such as development and grazing.

"They must not be in the same Arizona I'm in these days, because there's hardly any development going on anymore," said Ed Taczanowsky, director of the Southern Arizona Home Builders Association. "Anybody can go do a study, and anyone can interpret facts to their benefit."

WHAT'S NEXT: The wildlife service has 90 days to decide if the tortoise merits a full-scale review. If so, the service has a year from now to decide whether to propose a listing, and another year to decide whether to approve it.


SIZE: 6 to 14.6 inches long.

HABITAT: Arizona upland desert areas containing palo verde, saguaro and other cacti; the more barren Lower Colorado River section of the Sonoran Desert; and the rocky slopes of the Mojave Desert. Lives at elevations ranging from desert scrub at 510 feet to semi-desert grasslands at 5,300 feet.

STATUS: A separate Mojave Desert population of the same species is already federally protected.

FOOD: Known to eat 199 plant species, including grasses, herbs, spring and summer annual wildflowers, cactus fruit, forbs, succulents, desert vines and mallow.

POPULATION: Total unknown, but a new study from two California scientists says Sonoran Desert tortoise populations dropped about 3.5 percent annually from 1987 to 2006. Before the early 1950s, many populations reached densities of several hundred tortoises per square mile. Today, most contain no more than five to 50 per square mile, says the Arizona-Sonora Desert Museum.

AGE: Known to live up to 80 years in the wild and up to 100 years in captivity.

BEHAVIOR: Seasonal in nature, they are inactive in the Sonoran Desert from mid-October to late February or early March. Home ranges are typically about 30 acres but can be anywhere from 10 to 70 acres. Tortoises have been known to travel long distances.

* Contact reporter Tony Davis at 806-7746 or [email protected]

Originally published by TONY DAVIS, ARIZONA DAILY STAR.

(c) 2008 Arizona Daily Star. Provided by ProQuest LLC. All rights Reserved.