Good News Numbers
Aided by recent advances in technology, scientists have discovered new populations of several seriously imperiled species
- Jessica Snyder Sachs
- Oct 01, 2009
WHEN FEDERAL SCIENTISTS reported last fall that the northwest Montana population of grizzlies was more than twice as large as experts had previously thought, the news was hailed by conservationists. “The results show that we can turn species toward recovery when we put money, attention and habitat protections in place,” says John Kostyack, NWF executive director of wildlife conservation and global warming. “It’s an endangered species success story.”
Make that one of several recent success stories, all of them involving dramatically increased populations of rare species. Some involved surprise discoveries of hidden populations. Others, like the grizzly’s, confirmed—and even surpassed—hopes that recovery plans were working. On the following pages are some wildlife numbers worth celebrating.
Grizzly bears: FIRST RELIABLE CENSUS
Several years ago, Kate Kendall oversaw the fermenting of 2,200 gallons of rotting fish and cow blood for bear lure. "You can imagine the fun we had opening up those barrels a year later,” says the U.S. Geological Survey biologist. That would have been the summer of 2004, when Kendall deployed 230 field workers to construct more than 2,500 bear hair traps across 7.8 million acres of rugged wilderness in northwest Montana. The odor emanating from the lure poured in the center of each trap compelled hundreds of grizzlies, federally listed as threatened, to cross under or over a surrounding strand of barbed wire, usually leaving behind enough hair for DNA fingerprinting. The feat earned Kendall the stump-speech ridicule of presidential candidate John McCain, who cited her DNA study as an example of pork-barrel spending—his laugh line being, "I don’t know if that was a criminal issue or a paternal issue, but it was $3 million of our taxpayers’ money."
Contrary to the implication of wasted funds, Kendall used the bear DNA to produce the first reliable census of the largest grizzly population in the lower 48 states, and with it came some of the best U.S. conservation news in recent memory. The grizzly population in northwestern Montana now stands at 765—two and a half times the previous government estimates. Kendall’s census also brought encouraging news on the bears’ genetic diversity, on the number and distribution of females and on occupied range,
Western Lowland Gorillas: THE MOTHER LODE
Gorilla conservationists received a huge boost last year with the discovery of more than 125,000 western lowland gorillas in a remote area of Congolese rain forest. The tally required nearly 100 field staffers to spend months at a time in dense jungle, squirming their way along narrow animal paths and often sleeping in hammocks suspended over swamp sites. Scientists had long suspected that the near-impenetrable wilderness harbored gorillas, but the number discovered there surpassed researchers’ grandest hopes. “These figures show that northern Republic of the Congo contains the mother lode of gorillas,” says Steven Sanderson, president of the Wildlife Conservation Society, which sponsored the study. Indeed, the discovery more than doubles some previous estimates of the entire world population of western gorillas, which scientists had pegged at between 50,000 and 100,000.
“This should renew our conviction that it’s not too late for gorillas,” adds study leader Emma Stokes. “But it’s no time to be complacent. We need to act quickly and effectively if we are to ensure these gorillas’ future.” The dense jungle that hid the newly discovered population cannot be relied on to protect them, she explains. The population is on the front line of the next predicted outbreak of Ebola, a disease that has been decimating gorillas in recent years. Moreover, the population’s habitat is being bought up by mining and logging companies.
The good news is that the discovery has renewed the Congolese government’s interest in establishing a national park that could encompass much of the newly identified gorilla homeland. The Wildlife Conservation Society, in turn, is working with scientists to develop a gorilla Ebola vaccine and an effective way to administer it.
On another front, researchers with the society reported in June that they have found evidence of a population of the world’s least-known gorilla species, the eastern lowland gorilla, in the Democratic Republic of the Congo’s Itombwe region, an area where the species was not previously known to occur. It is the largest of four types of gorilla and lives exclusively in part of the country.
Long-Billed Curlews: MASSIVE FIELD EFFORT
Stephanie Jones fell in love with long-billed curlews early in her career as a U.S. Fish and Wildlife Service (FWS) biologist. “I was studying grassland passerines [songbirds] in Montana and kept getting bombed by these huge shorebirds defending their nests. I wondered, ‘What are you guys doing in the grasslands?’”
Jones learned that long-billed curlews—the giants of North American sandpipers—top her agency’s list of grassland birds of special concern, with a designation of “highly imperiled” (the most dire of five rankings). Once abundant across the Great Plains, these birds require short-grass and mixed-grass prairie for nesting—just the kind of habitat that has been plowed under for farming. Long-billed curlews have likewise lost much of their winter habitat along the California coast. Still, up until last year, no one knew how many of the curlews survived, with guesstimates ranging as low as 20,000.
So Jones took advantage of a recent funding opportunity to coordinate a massive field effort involving more than 100 U.S. and Canadian biologists and volunteer bird-watchers. In essence, Jones says, nailing down a statistically reliable estimate hinged on a kind of random sampling similar to that used by pollsters to predict presidential elections. Laying a grid over the curlew’s known breeding range, Jones deployed her army of field scouts to count curlews along hundreds of 20-mile routes crisscrossing the bird’s range. Importantly, she had them do so during four different survey periods, ranging from late March through mid-May, so as not to miss birds hidden in the grass during active nesting periods. From the field reports, Jones and her colleagues produced a population estimate of more than 160,000 long-billed curlews. That’s good news, even though the species remains of special concern owing to the continued destruction of its habitat, Jones says.
One major improvement: The new survey results will allow government agencies and conservation groups to concentrate their efforts in key areas. Among these are the hayfields of Nevada’s Ruby Valley, says University of Nevada biologist Alex Hartman. Here farmers don’t lay the kind of irrigation lines that disturb curlews. They simply divert melting snow to create swampy, lightly grazed grassland that re-creates the historic prairie habitat once maintained by herds of native bison, Hartman explains. Already, he has counted more than 500 curlews on 15,000 acres of flood-irrigated hayfields and 20,000 acres of rangeland—making Ruby Valley one of the most densely populated curlew habitats ever studied.
Black-Footed Ferrets: A GREAT SURPRISE
Hope gave way to despair in the mid-1990s with the disappearance of more than 200 black-footed ferrets released in conjunction with FWS by Wyoming Fish and Game Department scientists in southeastern Wyoming’s Shirley Basin, located south of Medicine Bow National Forest. The most endangered mammals in North America, the last known wild black-footed ferrets were taken into captivity in 1987 and bred for eventual release back into the wild. The disappearance of the Shirley Basin ferrets—the first and largest of 17 release sites—was attributed to outbreaks of plague and distemper. The diseases kill not only ferrets but also prairie dogs, the ferrets’ main prey. In 1997, biologists found only five ferrets at Shirley Basin, so the department shifted its priorities elsewhere.
So it was with great surprise in summer 2003 when researchers spotted 50-some ferrets at the site. “That was the year we realized that something special was occurring in Shirley Basin,” recalls state biologist Martin Grenier. A resumption of annual counts led to better and better results. As of last year, the rapidly growing population yielded a count of 239 ferrets. Extrapolating out from his study area, Grenier estimates that the entire Shirley Basin may be home to as many as 1,000.
Clearly, a few ferrets survived the twin diseases and reproduced, Grenier says. More surprising has been the rapidity of the population’s rebound, which defies the conventional wisdom that highly specialized predators reproduce slowly. Grenier speculates that black-footed ferrets may have evolved their unusual resiliency in order to survive the boom-or-bust cycles of prairie dog populations. “As exciting as the news is for Shirley Basin,” Grenier cautions, “we’re still struggling to have similar success stories elsewhere in North America.”
Tonkin Snub-Nosed Monkeys: NEW BREEDING GROUP
Thought extinct until 1989, Vietnam’s Tonkin snub-nosed monkey has remained one of the world’s most endangered primates. As of 2007, scientists estimated a total population of fewer than 150, confined to several small patches of forest in Vietnam’s northeastern provinces. Even more dire, only one of five known groups appeared to be breeding.
So it was with joy this past December that conservation biologist Le Khac Quyet and his colleagues reported the discovery of a new group of as many as 20 of these small, clown-faced monkeys—including three babies. Residents of Tung Vai, a village near the Chinese border, directed Quyet to the colony after he showed them a rare video of the species.
This second breeding group doesn’t come close to erasing the Tonkin snub-nosed from the list of the world’s most endangered monkeys. But it has prompted the Vietnamese government to protect the new colony’s habitat and to work with international aid groups to improve the lives of local villagers, lessening their need to clear surrounding forest and hunt monkeys for food.
Bowhead Whales: A THRESHOLD NUMBER
Subsistence whalers hunted the bowhead whales of the eastern Arctic for centuries on a relatively small scale. Commercial whaling was much more intensive. When the eastern population grew scarce, whalers shifted operations to the western Arctic. Protected from commercial whaling since 1946, both populations have survived—but the eastern one in perilous numbers. While western bowheads soon rebounded to pre-whaling numbers of around 10,000, scientists for a long time thought the eastern population was very small. The first signal that eastern bowheads might be doing significantly better came from reports by Canada’s native Inuit people. Admittedly, the Inuit were asking for increased quotas for their annual hunt. But last year a scientific survey backed up the Inuit reports.
Using satellite tracking combined with aerial surveys that covered a larger area than previous counts, Fisheries and Oceans Canada has now increased its estimate of the eastern bowhead population to around 14,400 whales. The upgraded numbers remain controversial, admits Fisheries and Oceans Canada marine biologist Pierre Richard. The International Whaling Commission’s Scientific Committee has critiqued the estimation method and revised the estimate to about 6,300 whales. Scientific counts have always been a challenge with this whale, Richard explains. “We’re talking about spotting a black animal on a vast dark sea,” he notes. “The truth may be somewhere between the International Whaling Commission’s 6,000 figure and our 14,000.”
In either case, related reports suggest that eastern bowhead populations may have finally reached a threshold number for a speedier rate of population growth in the years ahead—barring new threats stemming from global warming
Sociable Lapwings: NO SMALL CHALLENGE
A strikingly patterned plover, the sociable lapwing earned its name from the enormous flocks that once settled over the grasslands of Eurasia. During the 20th century, this plover’s world population fell dramatically—in part due to nest trampling and other factors related to livestock. By 2003 scientists estimated that only 200 breeding pairs survived.
Try 3,200. That’s the size of the flock discovered in autumn 2007 on a remote Turkish steppe. Ornithologists were led to the spot by a lapwing tagged in Kazakhstan earlier that year. The electronic device it carries broadcasts its position via satellite. The bird subsequently flew on to central Sudan, where researchers are now trying to locate its flock’s wintering grounds in even more remote wilderness.
Clearly, satellite tagging proved the key to finding the hidden population. The method posed no small challenge, says the ornithologist who used it: Robert Sheldon of England’s Royal Society for the Protection of Birds. Sheldon’s feat—funded under the Darwin Initiative, a United Kingdom government program—made sociable lapwings the smallest birds ever successfully satellite tagged. Only one in twenty sociable lapwings is large enough to carry a tag without being hampered, he explains. The hope is that advances in technology will shrink tags further for better tracking of even smaller birds
Ensuring the Future: ALL STILL IMPERILED
Looking across these success stories, it becomes clear that they share more than encouraging population growth. All seven species remain imperiled due to continued environmental destruction. “To be realistic, we can’t judge progress by mere numbers,” NWF’s Kostyack points out. “We have to do so by looking at how well we’re protecting wildlife habitat.” That, Kostyack says, will depend ultimately on how we tackle the combined threats of global warming and humankind’s expanding footprint on the natural landscape.
Jessica Snyder Sachs is the author of Good Germs, Bad Germs: Health and Survival in a Bacterial World (Farrar, Straus, and Giroux, 2007).
NWF in Action: Protecting Endangered Species
NWF has been in the forefront of efforts to save vanishing wildlife since the 1930s and continues this critical work today. The Global Warming Safeguards Program is an NWF initiative that seeks to protect wildlife habitat and species ranging from eagles and egrets to grizzly bears and whales in an increasingly dangerous era of climate change.