Population boom not enjoyed by this desert dweller

By Launce Rake

Monday, June 26, 2006 | 7:11 a.m.

They make their home in the brutal heat of the Mojave Desert, where they wander the harsh landscape of rock and sand, Joshua trees and cactus.

Although they have survived, even thrived, in the desert for millions of years, desert tortoises find themselves disastrously ill-equipped to deal with man.

If the perilous rivers of asphalt, off-road vehicles and curious wanderers don't kill them, a spreading lung disease might.

The result has been a dramatic plunge in the population over the last quarter century - by as much as 90 percent from the 1980 numbers, according to scientists. The declines have led to federal and local action.

"We'd like to make sure it survives," says Michael Connor, executive director of the Desert Tortoise Preserve Committee, one of several California-based nonprofit groups working to help the species. For the California groups, their Nevada counterparts, and federal, state and local government agencies, the priority is on habitat protection.

The range for the reptile includes the Mojave Desert and nearby areas - southeast California, southwest Utah, northwest Arizona and Southern Nevada. Most of the species is found in California and Nevada.

Connor points to sprawling development along the Interstate 15 corridor from Los Angeles to Las Vegas as the most direct threat to the animal's future.

In the closely monitored "areas of critical habitat," the U.S. Fish and Wildlife Service estimates there are about 6,300 tortoises on a swath of 1,600 square miles in the West - or about four per square mile, says Roy Averill-Murray, the agency's desert tortoise recovery coordinator. Some areas might have dozens, even hundreds per square mile, while other areas have been almost entirely depopulated.

The desert often supports so few tortoises to begin with because they survive on scarce desert vegetation, mostly greens that come from spring and winter rains.

But Averill-Murray and others believe a key factor in the crashing population numbers is the proximity of a well-traveled road. Roads and slow, lumbering tortoises just don't mix.

The answer to the riddle "Why did the tortoise cross the road?" is too often, "To be squashed half-way across."

Betty Burge, chairwoman of Clark County's nonprofit Tortoise Group, an organization of about 400 people formed in 1981 to preserve the animal, says that since the desert can only support a few tortoises per square mile, a lot of square miles are needed.

"You have to create a large enough area, a margin of safety. The population is not very dense," Burge says. "It's a matter of what the species requires.

"If we want to keep the species and other species that share its habitat, you have to protect the land."

Connor says that in the California portion of the Mojave species' range, the strategy has been to expand existing, protected land reserves and to make sure that incompatible uses - such as off-road motoring - don't occur within fenced areas.

In Southern Nevada, the U.S. Fish and Wildlife Service and local governments arrived at a different solution. The agencies agreed on a 30-year plan to limit urban development to 140,000 acres beyond the 2001 limits of developed, private land. Developers pay a $550-per-acre fee for conservation needs, which also benefit from the proceeds of federal land sales that provide new land for development.

Part of the effort, overseen by the Clark County Desert Conservation Program, relocates tortoises from land undergoing development. The tortoises go to a 27,000-acre relocation area south of Las Vegas near Jean, land the county has estimated could be home to 30,000 or more tortoises. The county is also considering four backup areas for relocation.

Christina Gibson, a conservation program analyst, says the goal is simple: "Survival of the species in the wild."

"We're doing it so far," Gibson says. "So far, we still have a lot of healthy tortoises. The population is self-sustaining despite the human impacts. Thus far, we as people in the Southwest have been successful mitigating the impacts of development. That's good news."

Monica Caruso of the Southern Nevada Home Builders Association, says that developers were at the table almost two decades ago when the conservation plan - subsequently extended to cover 78 rare plant and animal species - was forged.

"There was much input from all the stakeholders on this issue," she says. "An agreement was reached, and we've been operating under that agreement for more than a decade � As far as the developers are concerned, it is just a part of doing business."

Averill-Murray, with Fish and Wildlife, explains that the limitations on development aren't just to protect large amounts of habitat, but a diversity of habitat as well.

"Trying to maintain the diversity of the species, we can't ignore one part of the range," he says. "The purpose of the (federal) Endangered Species Act is to maintain the diversity of the species so it has the ability to maintain itself in the future."

Density is also an issue, he says: "By the time you add up enough square miles to have a viable population, the area adds up � Not all habitat is created equally. We don't understand why some areas might have more tortoises.

"Just because you have desert, there doesn't mean you're going to have a lot of tortoises there."

In the urban core of Clark County, however, development is rapidly burning through the 140,000 acres set aside for human needs.

Within a decade or so, the pace of development dictates that homebuilders, conservationists, federal and local agencies will have to come back to the table to renegotiate the federal permit that allows continued expansion of homes, businesses, roads and people into tortoise habitat in exchange for conservation measures.

Officials and scientists hope that when that process goes forward, they will have more information to work with to allow a peaceful coexistence. But, they admit now, fundamental questions still haven't been answered despite years, even decades, of research.

Questions such as: How many tortoises are there?

"It is a very difficult question � I can't give you a number," Averill-Murray says. "We're in the process of expanding that program and doing more with the program to see how different management actions correlate with actual desert tortoise numbers, to see how things in the landscape are affecting tortoises."

Others may ask if anyone should even care about this slow, scaly and fundamentally alien species.

Tortoises are "very benign, certainly not a threat to anybody," Averill-Murray says. "They are this kind of peaceful, slow-moving creature. A lot of people, those who are more connected to nature, but even those in urban areas who care about the natural world, feel that it is a living species that has an inherent right to exist, and it is not our place to eliminate it.

"The other point of view is that the desert tortoise is one of the top-level creatures in the ecosystem in the desert. It digs holes and creates burrows for other species. It is an integral part of the web of life. A huge number of species - mammals, reptiles, invertebrates - all use the desert tortoise burrows as shelters."

Although it is a federal crime for anyone to disturb a desert tortoise in the wild, with potential jail time and fines of $50,000 for a single incident, Clark County and Southern California residents still have ample opportunity to see the species.

Before they received federal protection, people took tortoises from the desert to keep as pets, and hundreds have lived for decades in people's back yards. Some are even breeding, and some are used as educational tools.

Clark County even has its own spokes-tortoise, Mojave Max, who annually signals the beginning of the spring season by emerging from its burrow at the Red Rock Canyon National Conservation Area. And each year, hundreds of captive, domesticated tortoises are legally adopted in Clark County.

Those which have been in captivity can't be released into the wild because they can spread diseases, scientists say, and there are serious concerns about maintaining the genetic integrity of the various subpopulations - the scientists don't want to mix them up.

The Tortoise Group's Burge, who has worked as a consultant for the county and federal agencies on tortoise issues, says she fears that one day, in the not-too-distant future, those in captivity may be the only ones left.

"I am not too optimistic," she says. "Things may turn around. I don't know. We're not catching up to the encroachment that's going on and the general attitude of people � More people are impacting the desert. The desert has limits.

"The desert doesn't recover. It's not like living where there's lots of rain. It makes it hard for any animal to live out there."

Gibson, with Clark County, agrees that it may look like there is a lot of room for the tortoise, but says, "They need a lot of space."

Inevitably, human activity will affect the tortoise, she says.

"Their lifestyle and habitat means that virtually every time we break new ground, we are affecting their habitat � Their habitat includes pretty much everywhere in Clark County where we would put up a new house."

Gibson acknowledges that not everyone sees the need to protect the reptile, but she says federal law calls for the protection of threatened animals and allows controlled development.

"There is a lot of controversy. The bottom line is we pretty much know that if we don't do the best we can, were going to lose something. We don't know what that's going to cost us in the long run. We're pretty sure if we would lose the tortoise, we are going to have some pretty strong impacts on other species," she says.

"The debate does go on, and there are people who argue very strong on both sides � but we are pretty sure that to not do anything would not be good for people."