新托福阅读材料汇总： 8 Wild Ways to Combat Invasive Species（1）

Fashionable Fur from Louisiana's Wetlands

Louisiana's wetlands are infested with more than a million large, beady-eyed rodents called nutria. These natives of South America were brought to the U.S. in the 1930s to stock fur farms. Soon after, farm escapees and took up residence in Louisiana's bayous, among other places. High demand for fur kept the wild population more or less in check for a few decades. But when the fur market crashed in the 1980s, the nutria population exploded. Now, an artist named Cree McCree is trying to make nutria fur fashionable again to control wild populations and save Louisiana's marshes from nutria noshing.

Nutria are grazers. After their numbers climbed aerial surveys revealed large swaths of wetland that had been eaten bare. Native muskrats graze, too, but they like to nibble the tender leaves of marsh plants, whereas nutria prefer to feast on a plant's base and roots. "The plant dies, and it relinquishes its hold on the soil," says Michael Massimi, invasive species coordinator at Barataria–Terrebonne National Estuary Program (BTNEP), a group set up to protect wetlands affected by nutria.

Land managers have tried several strategies to get rid of the pests, including an unsuccessful state campaign in the late 1990s encouraging locals to eat the rodents (nutria jambalaya, anyone?). What has been more successful is a state program that pays trappers $5 for each nutria tail they deliver. The program brings in 300,000 to 350,000 tails each year. If trappers can sell the fur or meat, they can earn even more. But the bulk of these products go to waste because demand is so low.

So, in 2009 McCree decided to try and reestablish a market for the fur. With a grant from the BTNEP, she challenged local designers to create apparel featuring the rodent's fur. "We're not trying to promote fur so much as we're trying to utilize a wasted resource," Massimi says. The project—Righteous Fur—aims to market nutria fur as a "guilt-free" alternative to traditional fur. McCree has already held two fashion shows in New Orleans, and many of the pieces sold. Even the animal's enormous orange teeth have made it onto the runway as necklaces and earrings. "When they're attached to a nutria they're pretty hideous," Massimi says. "But when you mount them on some Balinese silver, they actually look quite nice."

Goat Gluttony in Washington State

Goats aren't known for their refined palettes. They'll eat just about anything green. In places such as Hawaii or the Galápagos, where these grazers are unwanted invaders, this mindless munching has caused major damage. Goats strip away vegetation, which speeds up erosion. In the U.S. West, however, their insatiable appetite has actually been a boon in the fight against invasive species.

Tammy Dunakin, chief goat wrangler and owner of Rent-a-Ruminant, LLC, has a herd of about 120 goats on Vashon Island in Puget Sound that she rents out to clear weeds, including invasive species such as Himalayan blackberry, English ivy, Scotch broom and Japanese knotweed. For $725 a day the goats will munch and crunch their way through everything from leafy greens to thorny bramble. The herd can clear an acre in anywhere from six days to two weeks, depending on the density of the brush.

Goats don't have an impact on plant roots, so the weeds will grow back. But if they clip the same area a couple of times a year for a few years in a row, the plants will eventually die, Dunakin says.

What are the advantages of using goats? For one, they're "green". "They're not emitting gas fumes," Dunakin says. Goats are also agile. They can work in areas where it's difficult for people or machines to go. What's more, "they sterilize almost all the weed seed in their rumen so they don't propagate invasives elsewhere," she says. "It's a win–win all the way around."

Sniffing for Snakes on Guam

This tenacious terrier isn't searching for illicit drugs or bombs, he's sniffing for stowaway snakes. The tiny island of Guam is infested with them. In the past 50 years the invasive snakes have wreaked havoc on the island's native birds and lizards. Now the U.S. Department of Agriculture (USDA) uses dogs to prevent them from sneaking off the island and damaging other islands.

The brown tree snake—a native of Australia, Papua New Guinea and the Solomon Islands—arrived in Guam in the 1940s or 50s, most likely hidden in a load of cargo. Soon it began breeding in the wild. Guam was a brown tree snake's paradise, free of predators and full of defenseless prey. "They populated the whole island in relatively short order," says Daniel Vice, assistant state director of USDA Wildlife Services in Hawaii, Guam and the Pacific Islands.

At the peak of the population explosion, the island may have had more than 30 snakes per acre of forest. Since the snake's arrival, nine native bird species have disappeared from the wild. The two remaining species are "perilously close to extinction," Vice says. The snakes also bite locals and climb on power lines, causing frequent small-scale blackouts.

Naturally, other islands would like to avoid the Guam's fate. In 1993 the USDA set up the Brown Tree Snake Control Plan to keep the secretive snakes from sneaking off Guam. Officials set up traps and laid out toxic bait. They also began inspecting outgoing cargo. But brown tree snakes aren't easy to spot. A meter-long snake can fit inside a soda can with plenty of room to spare, Vice says. The inspectors needed something better than their own eyes to search for snakes. That's when they came up with the idea of snake-sniffing dogs.

Today, the USDA relies on a team of 16 Parson (Jack) Russell terriers. The dogs patrol Guam's ports and cargo warehouses "24 hours a day, seven days a week," Vice says. But because the other snake control measures work so well, they don't find many snakes—maybe half a dozen each year. Still, Vice points out that those are "high-risk snakes"—the ones ready to be shipped off the island. These dogged canines are the last line of defense.

Slurping Up Suffocating Algae in Hawaii

Biologists have a new weapon in the battle to save Hawaii's coral reefs from invasive algae—the Super Sucker. Essentially a giant vacuum, the Super Sucker can remove up to 360 kilograms of alien algae from the reef each hour.

Hawaii is home to at least 20 types of nonnative algae. But two kinds, brought to the island for research in the 1970s, are especially noxious—Gracilaria and Eucheuma. They grow rapidly, kill corals and destroy the diversity of the reefs by filling in the nooks and crannies where native sea creatures like to live and hide. "[The algae] takes a healthy diverse system and chops it off right at the knees," says Eric Conklin, the Nature Conservancy's marine science advisor in Hawaii.

The Conservancy has had some success holding community cleanup events where volunteers remove the algae by hand. But no one wants to spend every weekend picking algae off reefs. "We needed something that would basically produce the same effect as these big volunteer events, but that could be operated by a smaller number of people on a very regular basis, and in areas where community cleanups couldn't go," Conklin says.

So, in 2006 Conklin and his colleagues MacGyver-ed an alternative: a giant underwater vacuum. The pump—filched from a gold prospecting machine—sits above water on a floating platform, and the 100-foot hose extends down into the water. "We started off calling it 'The Super Sucker' as a joke," Conklin says. But eventually the name stuck.

The Super Sucker isn't that much faster than hand removal, but it requires a far smaller crew—a couple of divers feed algae into the hose and a few people work on the platform, picking out any by-catch and packing the algae into burlap bags. So far, the Super Sucker has helped restore more than eight hectares of reef.

Removing the algae, however, is only half the battle. To keep it from growing back, Conklin and his colleagues are looking at using native sea urchins, which feed on the algae. "The long-term solution," he says, "is better protection of herbivorous fish."