Preventing extinctions.

A wildlife manager offers a guarded prognosis for threatened species

Although species have become extinct throughout the history of the planet, the actions - and inactions - of humans have been at the root of many recent extinctions, says wildlife manager Charles L. Cadieux. Loss of

But humans have also taken action to preserve habitats and save species from extinction, says Cadieux, who offers his prognosis for the survival of several species native to the United States.

* Whooping crane. Just 50 years ago, only 21 whooping cranes existed in the world, and it was the "least likely to succeed candidate for resurrection from almost extinction," says Cadieux. With such efforts as the creation of a refuge in Texas, public-education campaigns about the birds' plight, and captive-breeding programs, there are now a total of 170 whoopers. The prognosis: "The whooper is going to make it."

* Blackfooted ferret. Ferrets were threatened with extinction because their diets consisted solely of prairie dogs; American settlers decided that their herds of cattle needed grass more than the prairie dogs did, so they poisoned them, cutting off ferrets' food supply. In the mid-1970s, no blackfooted ferrets were seen in the wild. One colony was then found, and a successful captive-breeding program established. A worry remains that the gene pool among the ferrets may be too narrow to ensure survival, but there is now known to be a total of 120 black-footed ferrets in the world - a remarkable increase over a few years ago. Prognosis: "[Q]uietly optimistic. I'll go out on a limb and say that this species will make it!"

* California condor. In the 1980s, a controversial program called for taking the few remaining condors out of the wild and breeding them in captivity. The program appears to be successful, for 52 condors have now been bred. The first two captive-bred California condors were released into the wild in January, Science News reported on January 25. Prognosis: "There is now a faint glimmer of hope."

* Manatees. The West Indian manatees found in Florida were once hunted. Now, though protected, they are imperiled by loss of habitat and encroachment by boating traffic. The boats can wound the manatees with their propellers or trap them in fishing lines. Some success has been reported in captive breeding of the U.S. subspecies, Cadieux reports. Prognosis: "[G]uardedly optimistic in USA waters, very poor in other habitats with the other subspecies."

* Florida panther. Though closely related to the unendangered mountain lions in the Rockies, the Florida subspecies may now number fewer than 50 animals. The panther requires a very large territory, but habitats were shrinking steadily until 1989, when the Florida Panther National Wildlife Refuge was established. The refuge will eventually offer 30,000 acres of land for the panther and "is the most encouraging sign in the long struggle to save this subspecies," says Cadieux. "But there is also the worry that the genetic base of this subspecies population is too small to allow its preservation. Prognosis: Not too good, but hopeful."

* Spotted owl. The northern spotted owl is a hot political issue in the Pacific Northwest, where the timber industry is an important economic force. The spotted owl thrives only in mature or "old-growth" forests, which the lumber industry wishes to harvest, selling the unprocessed logs to Asian buyers. Cadieux argues that such a short-term approach not only threatens the owls but is unsustainable for loggers in the long run. He suggests that tourism in Oregon brings in more money than does logging and that a better-managed forest resource would save both the owl and the long-term economic interests of humans. Prognosis: Questionable. "If we manage our forest resources for the greater good of mankind, the spotted owl will have no worries. But is that likely to happen?"

* Sea turtles. Although turtle eggs are targeted by an assortment of predators, once a turtle makes its way from its hatching in the sand to its life in the sea it stands a pretty good chance of long life. However, the outlook has dimmed in recent years due to human beings who, among other things, have built condominiums and marinas in the turtles' nesting areas. The turtles are also threatened by the nonenforcement of laws designed to protect them from shrimpers who inadvertently capture and drown turtles in their trawls. There are now five species of sea turtles in American waters that are endangered. Prognosis: "The battle has just been joined and there's a long, tough road ahead. We are not optimistic!"

Cadieux warns against neglecting the endangered species that we dislike or fear or consider insignificant or worthless, for "when any species of wildlife becomes extinct, the world is less safe for mankind." Efforts are under way to protect crocodiles, alligators, and rare poisonous snakes, even though these can cause harm to humans. Cadieux concludes: "I think it is a plus on the human side of the equation that humans are working to perpetuate a species (in fact many species) which can kill mankind. Is it a sign that man is becoming more civilized?"