Humans have reshaped the Earth in many ways — replacing forests with farms, for example, or carving canals and building dams — but according to a new study in the journal Science, one activity marks our single "most pervasive influence on the natural world": the systematic killing of large "apex" predators. Without big cats, wolves, sharks and whales to regulate ecosystems, the report says, populations of prey animals have exploded and run wild, throwing food chains out of whack.

 

"We now live in a world, really for the first time, where these big apex consumers are missing," says lead author James Estes, an evolutionary biologist at the University of California-Santa Cruz. "We see it on land, we see it on water, we see it in high latitudes, we see it in low latitudes." While humanity's big-game bloodlust isn't exactly breaking news, the report's brilliance lies in its scope, says University of Wyoming ecologist Matthew Kauffman, who wasn't involved in the research. "It's not reporting on any new findings, but I would say its value is that it is a synthesis," Kauffman tells PBS NewsHour. "It's showing us that there are top-down effects of large predators and large herbivores among many different ecosystems, functioning in many different ways. It allows us to see the full scope of the value of having top predators in ecosystems." As UC-San Diego oceanographer Paul Dayton tells USA Today, "I think this might be the most important paper Science has published in a long time."

 

The problem is rampant worldwide: The loss of wolves let deer take over Yellowstone, the loss of sharks let rays decimate Chesapeake Bay oysters, and even the loss of big herbivores like wildebeest in East Africa boosted plants that fuel bigger wildfires in the dry season. But it isn't confined to wildlife parks. "People who live in North America know it's hard to grow a garden because deer will eat it," study co-author Ellen Pikitch tells the Post. "You may hate wolves. ... But without them, the land changes. Deer carry ticks. We humans become more susceptible to diseases such as Lyme disease." Fixing the problem, Estes says, will require a new kind of wildlife conservation. "This has huge implications for the scale at which conservation can be done," Estes says. "You can't restore large apex consumers on an acre of land. These animals roam over large areas, so it's going to require large-scale approaches."

 

(Sources: Washington Post, USA Today, PBS NewsHour, National Science Foundation)

 

The International Whaling Commission has once again ended its yearly meeting in deadlock and disarray, the AFP reports, with pro-whaling nations staging a walkout Thursday to block a vote on creating a new whale sanctuary. The 63rd annual IWC meeting thus wrapped up as so many others have — without stopping the large-scale slaughter of baleen whales. Since banning commercial whale hunts in 1986, the IWC has struggled to enforce the moratorium, an often fruitless effort that critics say has undermined its credibility.

 

"You can only conclude that this commission — which, despite a moratorium, does not have a mandate to stop the large-scale hunting still going on — is genuinely dysfunctional," Frederic Briand, head of Monaco's IWC delegation, tells the AFP. "Since the moratorium was put in place in 1986, more than 33,000 whales have been killed." Latin American countries had tried to force a vote on a proposal to designate a whale sanctuary in the South Atlantic, but after pro-whaling nations walked out, the remaining delegates decided to table any vote on the sanctuary until next year's meeting. Japan, Norway and Iceland are the primary countries that have continued whaling despite the 1986 ban — thanks to various exceptions and loopholes — but they have also recruited an array of African and Caribbean nations to their side, leading to widespread allegations of vote buying. 

 

The issue of IWC corruption was one area where some progress was made at this year's meeting, the AFP reports: The commission adopted a British plan to discourage influence peddling by changing the process by which member nations pay their IWC dues. Whereas the dues have traditionally been paid via cash or check, they'll have to come by bank transfer in the future, an anti-corruption precaution already taken by other international organizations. Combined with new measures to protect smaller cetaceans like dolphins and porpoises, some whale advocates expressed optimism after this week's meeting concluded. "The commission, despite the recurrent standoff between pro-hunting and pro-conservation nations, is taking small steps in the right direction," says Sigrid Luber, president of Ocean Care.

 

(Sources: Agence France-Presse, Associated Press, BBC News)

 

If you're a baboon, you may want to think twice about vying to become top banana. So-called "alpha males" may dominate other members of a troop, enjoying more food and females than their underlings, but they're also haunted by the constant threat of potential usurpers, according to a new study in the journal Science. In fact, the study suggests, the relatively carefree — but not powerless — life of a beta male may actually be preferable to that of an alpha.

 

"Alpha males exhibited much higher stress-hormone levels than second-ranking [beta] males, suggesting that being at the top may be more costly than previously thought," the study's authors report. The study is based on nine years of research into wild baboons in Kenya, using fecal samples from males to determine their stress levels. Alpha males surprisingly showed levels of stress similar to their group's lowest-ranking members, although the two kinds of stress occur for different reasons. Low-ranking males live in fear of their superiors and must spend lots of energy searching for food, the researchers explain, while alpha males spend inordinate amounts of energy fighting to stay on top and racing to mate with as many females as possible. 

 

Beta males, on the other hand, get about the same amount of attention from females (albeit in the form of grooming), and still do "slightly better than predicted" at achieving their "full reproductive potential," according to the study. "After all," the New York Times muses, "when the alpha gets in another baboon bar fight, who's going to take the girl home?"

 

(Sources: New York Times, Los Angeles Times, AFP, AP)

 

An herbicide that received federal approval last fall is now being blamed in the deaths of thousands of trees across the U.S., the New York Times reports. Made by DuPont, the herbicide called "Imprelis" was quickly adopted by landscapers as an environmentally friendly way to kill broadleaf weeds like dandelion and clover, but now its reputation has been suddenly and dramatically transformed. 

 

"I've done nothing for the last three weeks but deal with angry customers," the service manager at one nursery in Michigan tells the Times. "We're seeing some trees doing OK, with just the tips getting brown, and others are completely dead and it looks like someone took a flamethrower to them." Imprelis seems to mainly affect trees with shallow root systems, the Times reports, including willows, poplars and conifers (especially white pine and Norway spruce, pictured above). Its chemical name is "aminocyclopyrachlor," part of a new class of weed killers that has been considered safer than previous types. DuPont and many of its customers had high hopes for the newly approved herbicide, due to its low toxicity in mammals, its effectiveness at low concentrations and its ability to kill weeds that other chemicals can't, such as ground ivy and wild violets. But when trees in treated areas began dying off around Memorial Day, it quickly became clear something was wrong.

 

"This is going to be a large-scale problem, affecting hundreds of thousands of trees, if not more," says horticulture and forestry expert Bert Cregg of Michigan State University. DuPont has expressed skepticism that Imprelis is really what's killing the trees, implying that workers may have applied it improperly or mixed it with other herbicides, although the company does recommend not using it near white pines or Norway spruce. "We are investigating the reports of these unfavorable tree symptoms," DuPont spokeswoman Kate Childress tells the Times. "Until this investigation is complete, it's difficult to say what variables contributed to the symptoms." The EPA, which approved Imprelis for sale last October, says in a statement that it's "taking this very seriously."

 

(Sources: New York Times, DuPont)

 

Nobel laureates denounce nuclear weapons, the Deepwater Horizon spill is capped, and more.

 

— Russell McLendon