Fast Decline of Slow Species

There's a quiet crisis in America's rivers, lakes and freshwater wetlands

  • NWF Staff
  • Oct 01, 1998
Muddy brook lives up to its name. The water, which is the color and consistency of last week's coffee, flows sluggishly through a swampy bottom where red maples flicker with a hint of autumn. In short, this stream in New York's lower Hudson River Valley is a great place for freshwater turtles. And herpetologist Michael Klemens, chest-deep in the murk, is hoping for a varied haul of the creatures as he hoists a wire-mesh trap baited with a slowly dripping can of cheap ("three-for-a-buck") sardines. "If we're really lucky, we'll have a rare wood turtle," he tells a visitor watching from a bridge.
Today, however, the cage is empty except for a single painted turtle--probably the most familiar turtle in North America due to its unique coast-to-coast distribution, its vivid red and yellow markings and a habit of basking for hours on sun-washed logs and rocks. But Klemens, who directs metro-region programs for the Wildlife Conservation Society at the Bronx Zoo, isn't too disappointed. "I respect all turtles," he says, "and this is an old, old male. Look at those long fingernails. They're used to stimulate a female by tickling her face." The scientist measures a shell stained dark red with decades of organic and mineral deposits. He then notches it for future identification, explaining that "painters" are unusually common turtles because of their ability to flourish in man-made ponds and reservoirs, even in polluted habitats.

It's good to know that at least one of the 46 species of freshwater turtles found north of the Mexican border is doing well, because there's a quiet crisis in our inland rivers, lakes and assorted wetlands. Local, state and regional populations of these marvelous two-shelled creatures whose ancestors witnessed the dinosaurs' rise and fall now face their own extinction. The causes, of course, stem from the activities of the upstart human species. A short list of turtles that are in trouble to one degree or another would include the bog turtle, wood turtle, spotted turtle, Blanding's turtle, red-bellied turtle, eastern and ornate box turtles, Florida softshell turtle, alligator snapping turtle, various map turtles that live in single river systems in the South and the western pond turtle, one of the very few aquatic species found west of the Great Plains.

Most of these turtles, and others, are listed as endangered, threatened or species of special concern by state wildlife agencies in the regions where they occur, and some are federally listed. Experts warn that many of them could vanish from the face of the continent in the next century. Yet the decline of the world's richest freshwater turtle fauna has gone largely unnoticed while conservationists have been busy saving the more glamourous representatives of the chelonian clan: the sea turtles, the desert tortoise and the diamondback terrapin of brackish coastal marshes.

Stories in national magazines, meanwhile, have spotlighted the smuggling into the United States of such coveted exotic specimens as the plowshare tortoise from Madagascar, one of the world's rarest turtles and worth as much as $10,000 to an American collector. But the media have mostly ignored the fact that many thousands of increasingly scarce native turtles are being shipped overseas.

"Freshwater turtles are beset with a host of problems and need a lot more attention," says Klemens. He ticks off habitat destruction and fragmentation, the collecting of protected species for a lucrative black market, a huge international pet trade in more common species, the runaway demand for turtle meat and shell in the Far East and pollution from cropland runoff and industrial chemicals.

The creatures are also vulnerable because they produce few eggs. A female sea turtle might lay 200 eggs compared with 3 to 5 eggs for a bog turtle or 8 to 12 eggs for a wood turtle. Also, most eggs do not survive and usually few of the hatchlings survive. "The one thing freshwater turtles have had going for them is a long life span, more than 120 years for the box turtle," says Klemens. "Animals programmed by nature to reproduce for 60 or 70 years are now living for a fraction of that time. They're being taken from the wild or killed by cars and predators like raccoons, which thrive in disturbed habitats and can pull a turtle out of its shell limb by limb. I can look at a population and tell that it's dying out because there are basically no young or teenage turtles, just aging adults. It may be 30 years or longer before the last remnants are gone, but the population already is functionally extinct."

Terrestrial lives: Klemens' point is driven home by the case of the wood turtle, which carries a deeply sculptured upper shell, or carapace, as long as 9 inches and is found near woodland streams in the Northeast and the Great Lakes states. Every freshwater turtle needs some upland habitat, if only for a nest site. That's true even of the monstrous alligator snapping turtle, though the 200-pound creature rarely leaves the bottom of southern rivers and lakes, where it wiggles a pink wormlike appendage on its tongue to attract fish. But the wood turtle and several other species lead largely terrestrial lives from late spring to fall. While the creatures' aquatic habitats might be protected by laws against destroying wetlands, their complex home ranges are routinely chopped up by new roads and country home developments.

After emerging from hibernation, wood turtles wander into forests, meadows and old fields, feeding on moss, grass, leaves, wild berries, insects, snails, earthworms and carrion. "A wood turtle might travel two miles from its riparian habitat," says Klemens, "but there is no population in Connecticut that's less than a mile from a paved road. Every wood turtle in the state crosses a road at least once or twice a year, and a lot of them get run over." He points out that wood turtles do not mature until their second decade; a female produces her first eggs around the age of 15. "The chances she'll live out her reproductive mandate become less and less as the habitat becomes more and more fragmented," Klemens says. Most female turtles need a half century to produce a handful of offspring that survive to reproductive age.

Moreover, wood turtles are prized as pets for home aquariums, and the removal of animals from a population already hard hit by the loss of older juveniles and adults could be its death knell. Even wilderness recreation can have a devastating impact. In 1974, a public water utility opened its large, protected landholdings near New Haven, Connecticut, to hiking and fishing. By 1993, the number of use permits issued annually had climbed to 11,000 and two once-thriving wood turtle populations totaling 84 animals had completely disappeared. Researchers blamed handling and removal of turtles by visitors and disturbance by their dogs, road kills from increased traffic and predation by raccoons attracted by garbage and dead fish.

Chancy habitat: The little bog turtle, North America's smallest chelonian, has a special habitat problem. Bog turtles carry a domed shell 3 to 4 1/2 inches long and prey on a variety of invertebrates from spiders to millipedes to dragonflies. They are the most coveted native aquatic turtle, and collecting on an international scale is blamed for wiping out whole populations. But as turtle authority Carl Ernst of George Mason University in Virginia tells it, "The bog turtle by its habitat selection has threatened its own continued existence."

Bog turtles live in places like marshy meadows, tamarack swamps or sphagnum bogs which are in the last stages of natural succession from wetland to dry land. "Living in such a chancy habitat may be all right if there are other such habitats nearby to which the turtles can migrate if their home bog dries up," Ernst says. But over the past 30 years, a great many of these small boggy places have been drained or filled for commercial and housing development. One of the more productive bog turtle sites in New York is a shallow seepage in the middle of a cow pasture a few miles from Muddy Brook--in a town where a premium on land for new homes, shopping centers and industrial parks is driving out agriculture.

The bog turtle, known in 12 states from Massachusetts to Georgia, was recently designated as threatened by the U.S. Fish and Wildlife Service, but most of its breeding sites are on private land and relatively few of them--5 of 25 in New York, for instance--are believed to be capable of supporting healthy populations into the next century. The agency says it will work with landowners to help the species but will not designate critical habitat for fear of alerting collectors, who will pay up to $1,000 for a female bog turtle.

Pet trade: Only five other freshwater turtles have protection under the federal Endangered Species Act, and all of them have very restricted ranges. They include two of the 12 species of map turtles: the ringed map turtle, confined to the Pearl River watershed in Mississippi and Louisiana; and the yellow-blotched map turtle, found only near the mouth of Mississippi's Pascagoula River. Map turtles are shy animals that live in big rivers and lakes, mainly in the immense Mississippi River drainage, where sunny basking sites like fallen trees and cypress knees are abundant. Female map turtles are generally twice the size of males; in some species they attain a carapace length of 12 inches or more and have remarkably broad heads for crushing the shells of large snails, clams and mussels. The small males eat a lot of insects.

Collectors prize map turtles for the beautiful markings on their shells, which with a little imagination suggest the squiggles on topographic maps or marine charts. Several species also have saw-toothed keels that add to their allure. U.S. Fish and Wildlife Service figures show that the number of live map turtles exported for the pet trade, mainly to Germany and Japan, soared from 673 in 1989 to 56,749 in 1994, the last year that adequate records were kept. But because of error and avarice, such figures only hint at the actual numbers of turtles sent overseas. A 1994 report by the Humane Society of the United States suggests that dealers habitually underreport the turtles they ship by two or three times because they know that customs agents are too overworked to check the boxes unless they suspect wrongdoing. The tactic reduces duty fees and helps ensure little attention from conservationists and others.

"Reliable estimates of the number of turtles that are collected, sold or remain in the wild simply do not exist," says Allen Salzberg of the New York Turtle and Tortoise Society. And when it comes to baby red-eared sliders, the reported shipments from 50 or so turtle farms in Louisiana are almost unfathomable: 8,326,635 in 1996, 43,013,650 since 1989 according to statistics assembled by Teresa Telecky of the Humane Society.

The slider, named for the bright red slash behind its eyes, is often the first pet turtle parents buy for young children. Sliders are still fairly common in quiet waters in the Mississippi Valley where there is an abundance of aquatic vegetation. But as Salzberg emphasizes, the commercial ponds are stocked with gravid adult females that are taken from the wild so their eggs can be collected for incubation. "This is not captive breeding," he says, warning that a slider population crash is inevitable.

There is also a huge domestic market for live turtles. In a strip-mall pet store in the New York suburbs where Salzberg stops "to check out what's going on," aquariums stacked floor to ceiling display an astonishing variety of reptiles and amphibians. Most of the animals are exotic species like the rare starred tortoise from the jungles of India and Sri Lanka. But there are tanks full of red-eared sliders of all sizes, spotted turtles, several kinds of map turtles and hatchling Florida softshells that also are raised (legally) from the eggs of wild-caught females. (A Florida wildlife officer recently encountered two men with 40,000 softshell eggs in their possession.)

Turtle meat: Softshell turtles with their flat, leathery carapaces have been described as "animated pancakes" for their ability to move or swim with astonishing speed and agility--a good idea since they are a favorite food of alligators. They have long, fully retractable necks that are used to strike in snakelike fashion at fish and other prey. The Florida softshell, found in virtually every lake, spring, canal and roadside ditch in the state, is the largest of North America's three softshell species; the females, considerably bigger than the males, weigh as much as 55 pounds. It is also our most fecund freshwater chelonian, nesting five or six times a year with an average clutch size of 20 eggs.

But the pet trade is a minor threat to softshell turtles compared to a burgeoning Asian market for turtle meat and bone. Softshell turtles are not protected in Florida, and there are no restrictions on the take. Large softshells, mostly females, are butchered, boxed, frozen and labeled as "seafood" to avoid attention and concern from the U.S. Fish and Wildlife Service. Smaller animals, meanwhile, are shipped live for Chinese consumers who grind the shells and ribs into a supposedly medicinal broth. The Florida Game and Fresh Water Fish Commission has no idea how many softshell turtles are being harvested, but reports that the demand for turtle meat in both the domestic and export markets far exceeds the supply.

If there is an upbeat note about the relentless exploitation of native freshwater turtles, it would be the 1995 listing of both box turtle species on Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora. CITES requires export permits from the country of origin, and the current zero quota for box turtles effectively shut down a European market for an estimated 35,000 of these strikingly marked chelonians every year.

Box turtles are named for a hinged bottom shell, or plastron, that locks against the carapace to protect the animal's vulnerable parts from predators. Their long lives are spent on dry land in a home range that may not be much larger than a football field, although they are seldom found far from a wet place where they can luxuriate in a long soak. In the mid-1800s, one box turtle with a marked shell was discovered less than a quarter mile from the spot where it had been captured 60 years earlier. After all, turtles have had all the time in the world to explore their neighborhoods at their own slow pace.

Now, however, their time may be running out.

Field editor Les Line lives in the Hudson Valley, where a school district recently spent $1.5 million to successfully move and preserve a wetland used by rare turtles so new classrooms could be built.

Helping a Turtle Cross the Road

According to the New York Turtle and Tortoise Society, there are two easy steps anyone can take to help native turtles. One is to leave them in the wild. If a child brings a turtle home, take it back to the spot where it was found.

Another is to help a turtle cross the road. Always put the animal on the side of the road in the direction it was heading, since turtles know where they are going, and always be very careful of traffic. Large softshell and snapping turtles can be quite dangerous and are best left alone unless you are certain you know how to handle them safely.

Protecting Wetlands

Wetlands are essential for the survival of freshwater turtles as well as an array of other wildlife, and NWF has made conservation of these critical habitats a central focus. Two recent highlights:

NWF has been fighting in court and lobbying to ensure that federal agencies fully apply the strong wetland protections established by the Clean Water Act. In a victory in federal court in April, NWF won a suspension of a broad permit that allowed filling of wetlands nationwide for the construction of single-family homes with no public notice and no environmental review. NWF also represented 16 other organizations in the case.
NWF and the Florida Wildlife Federation, an NWF affiliate, recently launched a joint project to ensure conservation of the Western Everglades. The project is also promoting ongoing restoration of the entire Everglades watershed, home to turtles and many other wetland-dependent species.

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