Defenders Magazine

Wild Life: All Oiled Up

All Oiled Up

Nearly two decades after the Exxon Valdez dumped its 11-million-gallon load of heavy crude in Alaska's Prince William Sound, new evidence shows that the most disastrous oil spill in U.S. history is even worse for wildlife than previously thought, according to a study that appeared in a recent issue of Environmental Science and Technology.

Researchers found significant amounts of oil from the tanker buried in the sand and silt within a low-tide zone, a primary feeding ground for sea otters, ducks and other wildlife. After randomly digging hundreds of pits along 32 stretches of shoreline on the island most severely harmed by the spill, researchers found oil from the tanker at nearly half of the sites.

This doesn't bode well for a sea otter population still struggling to recover: To search for prey, the otters dig thousands of pits a year. "This continued exposure to the oil may be the missing piece in the puzzle explaining why they are not recovering as quickly as expected," says research chemist Jeffrey Short of the National Marine Fisheries Service in Juneau, Alaska. "Up to six miles of shoreline is still contaminated with as much as 200 tons of oil still in the sound."

The Exxon Valdez Oil Spill Trustee Council funded the study as part of its mandate to measure the spill's toll on wildlife. State and federal regulators are currently considering what additional steps to take to protect imperiled creatures in the area.

Extinction is Forever

Rachel Carson first warned about a silent spring in 1962. Back then, indiscriminant use of pesticides was to blame for bird loss. Today birds are declining primarily because of habitat loss--especially deforestation and destruction of breeding and nesting grounds--and new research is showing that entire species are going extinct more rapidly than previously thought.

Scientists had previously documented the extinction of about 130 bird species since 1500, but that number is now closer to 500, according to new research published in the Proceedings of the National Academy of Sciences. Add invasive species and climate change into the mix and extinction rates could skyrocket to 10 species a year, researchers say.

"Habitat destruction has long been understood as the major factor driving extinction, but global warming, which will simply eliminate so many habitats over the course of this century, is an insidious force that will drive species of birds and other organisms to extinction in large numbers even if they are theoretically saved in preserved natural areas," says Peter Raven of the Missouri Botanical Garden, who released the study along with other scientists at Stanford and Duke universities.

Researchers arrived at the new figures after factoring in previously unknown bird species--recently discovered as fossilized remains--and species that haven't been officially declared extinct--even though scientists haven't documented their existence for decades. Of the 10,000 known bird species, about an eighth are on the IUCN Red List of Threatened Species and in danger of going extinct. "Comprehensive monitoring and attention to all global problems will be necessary if we are to get through this century with most of the species we have now," adds Raven.

Attack of the Aliens

It isn't causing widespread public panic like the Orson Wells' broadcast of Martians invading New Jersey, but this alien invasion does have scientists up in arms about Antarctica.

The frozen continent is seeing an influx of adventure tourists--some 26,000 a year--who are apparently bringing in bluegrass on their boots and North Atlantic spider crabs in their ship's ballast water. For the first time, the turf grass has taken root and is starting to spread around at least one of the research stations, and spider crabs have made it to the waters surrounding the Antarctic Peninsula.

"In the rest of the world we have seen the havoc that is wrought by alien species, says Maj De Poorter, coordinator of the Invasive Species Specialist Group of the IUCN. "They are the second biggest cause of biodiversity loss globally and the biggest on islands. For instance, bird species are being driven to extinction by rats and other predators, native plants are being strangled by alien vines and climbers and alien ants are killing everything in their path in far too many places. In the Antarctic we are still one step ahead of this, and we have a unique opportunity to prevent the scourge of biological invasion arriving on this continent."

Each season now also sees as many as 10,000 scientists in Antarctica. With some come dogs, which have passed canine distemper to seals. The seals, along with penguins, have also been infected with bacteria from human waste.

"Evidence from other parts of the world has shown that there is a direct link between numbers of people visiting a remote area and the numbers of non-native species that survive," says John Shears of the British Antarctic Survey. "Once established, they can be very difficult to eradicate. Prevention is better than cure."

Scientists worry that global warming will only make it easier for invasives to gain a foothold in a place where once they couldn't survive.

Those who care about the world's coldest continent are fighting back. Antarctic experts meeting in Edinburgh, Scotland, last June agreed to push protective measures such as dumping ballast water before reaching the Southern Ocean and mandating a code of conduct for all future visitors.

A Whooper of a Story

Here's a well-hatched plan that--well--actually hatched. Following decades of work by conservationists to increase numbers of endangered whooping cranes in the eastern United States, this summer two chicks were born in the wild in the Midwest for the first time in more than 100 years.

"I just think it's fantastic," says Chris Danilko with Operation Migration, a group that's been working with U.S. Fish and Wildlife Service and others since 2001 to help the birds recover. "This is proof that we can have a self-sustaining population." The tallest bird in North America, the whooping crane nearly went extinct in the 1940s.

Project overseers hope that both chicks, hatched in Necedah National Wildlife Refuge, will follow their parents flying south this fall. Another 18 juveniles will be led by an ultralight aircraft--with pilots outfitted in costumes to look like adult cranes--to the Chassahowitzka National Wildlife Refuge in Florida. Cranes learn migratory routes from their elders, unlike songbirds, which are genetically programmed to migrate using celestial and magnetic cues. About 60 adult birds have been spending the winter in Florida and other areas in the Southeast since 2001.

The only other migrating flock numbers about 200 and flies between Canada and the Texas Gulf Coast.