Thursday, December 4, 2014

Lethal control of wolves backfires on livestock

WSU researchers find shooting carnivore leads to more dead sheep and cattle
Washington State University researchers have found that it is counter-productive to kill wolves to keep them from preying on livestock. Shooting and trapping lead to more dead sheep and cattle the following year, not fewer.
Writing in the journal PLOS ONE, WSU wildlife biologist Rob Wielgus and data analyst Kaylie Peebles say that, for each wolf killed, the odds of more livestock depredations increase significantly.
The trend continues until 25 percent of the wolves in an area are killed. Ranchers and wildlife managers then see a "standing wave of livestock depredations," said Wielgus.
Moreover, he and Peebles write, that rate of wolf mortality "is unsustainable and cannot be carried out indefinitely if federal relisting of wolves is to be avoided."
The gray wolf was federally listed as endangered in 1974. During much of its recovery in the northern Rocky Mountains, government predator control efforts have been used to keep wolves from attacking sheep and livestock. With wolves delisted in 2012, sport hunting has also been used. But until now, the effectiveness of lethal control has been what Wielgus and Peebles call a "widely accepted, but untested, hypothesis."
Their study is the largest of its kind, analyzing 25 years of lethal control data from U.S. Fish and Wildlife Services Interagency Annual Wolf Reports in Montana, Wyoming and Idaho. They found that killing one wolf increases the odds of depredations 4 percent for sheep and 5 to 6 percent for cattle the following year. If 20 wolves are killed, livestock deaths double.
Work reported in PLOS ONE last year by Peebles, Wielgus and other WSU colleagues found that lethal controls of cougars also backfire, disrupting their populations so much that younger, less disciplined cougars attack more livestock.
Still, Wielgus did not expect to see the same result with wolves.
"I had no idea what the results were going to be, positive or negative," he said. "I said, 'Let's take a look at it and see what happened.' I was surprised that there was a big effect."
Wielgus said the wolf killings likely disrupt the social cohesion of the pack. While an intact breeding pair will keep young offspring from mating, disruption can set sexually mature wolves free to breed, leading to an increase in breeding pairs. As they have pups, they become bound to one place and can't hunt deer and elk as freely. Occasionally, they turn to livestock.
Under Washington state's wolf management plan, wolves will be a protected species until there are 15 breeding pairs for three years. Depredations and lethal controls, legal and otherwise, are one of the biggest hurdles to that happening.
Wolves from the Huckleberry Pack killed more than 30 sheep in Stevens County, Wash., this summer, prompting state wildlife officials to authorize killing up to four wolves. An aerial gunner ended up killing the pack's alpha female. A second alpha female, from the Teanaway pack near Ellensburg, Wash., was illegally shot and killed in October.
That left three breeding pairs in the state.
As it is, said Wielgus, a small percentage of livestock deaths are from wolves. According to the management plan, they account for between .1 percent and .6 percent of all livestock deaths--a minor threat compared to other predators, disease, accidents and the dangers of calving.
In an ongoing study of non-lethal wolf control, Wielgus's Large Carnivore Lab this summer monitored 300 radio-tagged sheep and cattle in Eastern Washington wolf country. None were killed by wolves.
Still, there will be some depredations, he said. He encourages more non-lethal interventions like guard dogs, "range riders" on horseback, flags, spotlights and "risk maps" that discourage grazing animals in hard-to-protect, wolf-rich areas.
"The only way you're going to completely eliminate livestock depredations is to get rid of all the wolves," Wielgus said, "and society has told us that that's not going to happen."

Tuesday, August 5, 2014

Scientists Call for Increased Conservation Efforts to Save Black Bears

Between 1880 and 1920, the Central Interior Highlands (CIH), consisting of Missouri, Oklahoma and Arkansas, saw the height of deforestation that also decreased the habitat for black bears and other forest species. To combat the decline of black bears and repopulate the mountainous region, more than 250 bears from Minnesota and Manitoba were relocated to Arkansas in the 1950s and 1960s. Now, researchers at the University of Missouri have analyzed genetic diversity in black bears in the CIH and have determined that coordinated conservation management is still needed to maintain healthy populations of black bears in the region.

“The focus of our study was to determine the effects of the reintroduction of black bears in the Ozark and Ouachita Mountains and how that reintroduction affected population genetics in the region,” said Emily Puckett, a doctoral candidate in the Division of Biological Sciences at MU. “We also wanted to determine if we could find evidence of the population that was formerly here and whether or not they mated with the reintroduced bears or if they had gone locally extinct following deforestation.”
Study results suggested that black bears were present throughout the CIH in the 1920s, contrary to previous beliefs. Current research indicates that the bears had a remnant lineage in the northern Ozarks of Missouri, Puckett said.
Additionally, the team found that current black bears went through a brief “bottleneck,” where bears were cut off from each other and genetic diversity was reduced. However, the team also determined that the reintroduction of bears to the CIH in the 1950s and 1960s helped to restore diversity and increase population size in the Ozarks and Ouachitas.
“We observed the genetic signature of the Ozark population from Arkansas in Missouri, meaning that the bears moved north,” said Puckett. “These bears bring with them their higher genetic diversity which may help Missouri’s bear population in the future. The movement north also indicates that formerly fragmented forests may have regrown thereby connecting Missouri bears to the Ozark subpopulation that was further south.”
Puckett and her team including Lori Eggert, associate professor of biological sciences in MU’s College of Arts and Science, and Jeff Beringer from the Missouri Department of Conservation, collected and analyzed DNA samples from black bears from five geographical locations.  Hair samples from Arkansas, Oklahoma and Missouri were analyzed. Additionally, blood samples from hibernating bears in Minnesota and tissue samples from Manitoba were examined for their genetic signatures.
“This represented one of the largest sample sizes in a study of this type,” Eggert said. “By using multiple genetic markers on samples collected from Missouri and Arkansas, hunted bears in Oklahoma and live dens in Manitoba, we were able to conduct genetic and statistical analyses to analyze trends and gain robust conclusions.”
The team suggests that conservation efforts to promote forest connectivity will help protect bears throughout the region, so that subpopulations are not isolated, as was the case in Missouri, and genetic diversity remains high. State agencies in Arkansas, Oklahoma and Missouri could work together to unify bear management since this study observed populations spanning state borders.
“Geneticists get concerned when populations have low genetic diversity,” Puckett said. “Low diversity can be indicative of low population size. When harmful mutations arise in a gene pool with low diversity, they may increase in frequency leading to poor fitness and health in the population. That’s why these management suggestions are so important.”
The study, “Influence of drift and admixture on population structure of American black bears (Ursus americanus) in the Central Interior Highlands, USA, 50 years after translocation,” was published in the journal Molecular Ecology. Funding for the project was provided by the Missouri Department of Conservation, Arkansas Game and Fish Commission, U.S. Fish and Wildlife Service, and Safari Club International.

Friday, July 18, 2014

Grizzly bear 'highway' in coastal British Columbia

A novel, First Nations-led research collaboration has revealed a previously undocumented grizzly bear aggregation in coastal British Columbia, one of the most southerly aggregations of salmon-feeding grizzlies in North America. Using non-invasive DNA analysis, the authors describe a grizzly bear "highway," identifying nearly 60 individual bears, many who travelled hundreds of miles from surrounding areas to feed on autumn-spawning salmon in the Koeye River. The research was guided by the customary law and cultural practices of the Heiltsuk First Nation and recently published in the journal Ecology and Society.

Conducted over three years, the study also provides potential early evidence of a declining bear population in the area and links this to the decreasing availability of salmon. The project demonstrates a model for resource management by indigenous people, in which research is embedded within a socially and culturally appropriate framework.

"What's really novel here is the set of relationships, and deep cultural histories, that guided applied conservation science," said Chris Filardi, director of Pacific programs at the American Museum of Natural History's Center for Biodiversity and Conservation and an author on the paper. "In this collaborative setting, results are directly relevant to tribal leadership impacting conservation in ways that elude most scientific studies."

The study was centered in the Koeye River Conservancy, one of numerous protected areas designated by the Heiltsuk First Nation in the Great Bear Rainforest of British Columbia in 2009. The Heiltsuk people settled in this area more than 9,000 years ago and are now reasserting their rights as guardians of the Koeye River. To realize this renewal,

they established the Qqs (Eyes) Projects Society, a Heiltsuk-driven nonprofit that builds capacity for research, monitoring, and tribal governance of high-value stewardship areas. In 2006, the Heiltsuk people partnered with the Museum and The Nature Conservancy to implement a grizzly bear survey project with a unique dimension: from the outset, the study was designed to uphold the Heiltsuk Nation's Gvi'ilas, or customary law, a set of guiding principles that frame a worldview focused on core values.

"What appealed to us was the opportunity to root science in strong cultural stewardship frameworks," said Qqs' William Housty. "We articulate specific Heiltsuk laws and customs related to respect and reciprocity and match them with scientific tools and knowledge to put those principles in action."

During the survey, grizzly bear hair was collected as the animals walked by scented wire snares set up in the area during salmon-spawning season. As part of the non-invasive aspect of the work, the "baits" did not provide rewards to the bears visiting the snares.

At the same time, the team calculated the accessibility of salmon to bears with an index based on the number of salmon that return to the Koeye each year; water flow; and water visibility. Over the three-year survey, they found a decreasing population of bears in the Koeye, likely tied to declining salmon accessibility.

"This study shows that protected areas are not enough. We knew that bears are wide-ranging, but this study shows how vulnerable they are to a variety of threats," said Richard Jeo, a staff scientist for The Nature Conservancy. "Scientific insight can help guide management but the fate of these bears and the rainforest where they live is still largely in the hands of a few First Nations."

"We want to practice land and resource management with strong information empowering our decision makers," Housty said. "Whether it's regulating activities like forestry and tourism or indigenous-led advocacy to end trophy hunting for bears, ensuring that we ourselves are leading the best available science is a critical part of asserting our sovereignty and stewardship responsibility."

The next step for the group is to expand survey work to include a broader sampling of culturally significant salmon streams, improve linkages to salmon monitoring, and directly involve Heiltsuk families and their histories with places they share with bears.

"What is most important is Heiltsuk-driven science across the range of areas used by bears and people," Filardi said. "Knowledge about the interwoven ecologies of bears, salmon, and people can guide actions unavailable in places farther south where bears and salmon have vanished, or across broader society, where we have not yet come to value bears and salmon as integral to our physical and spiritual lives."

Friday, May 9, 2014

Research indicates coyote predation on deer in East manageable

IMAGE: This is an Eastern coyote.

Coyotes are a major predator of white-tailed deer across the East, especially fawns born each spring, but wildlife managers nonetheless are able to stabilize and even grow deer herds, according to researchers in Penn State's College of Agricultural Sciences.

Coyotes -- Canis latrans -- are a relatively recent arrival to eastern North America, appearing first in the region in noticeable numbers in the 1970s. They are a significant source of deer mortality and most often prey on whitetails in the earliest months of their lives. Coyotes have long inhabited the American West.

With the range expansion of coyotes eastward, and their crossbreeding with gray wolves (Canis lupus) along the way, Eastern coyotes are larger than their Western counterparts. Many people are concerned that their predation may be adversely affecting Eastern deer populations. Recently, lawmakers in Pennsylvania proposed placing a bounty on coyotes to incentivize their destruction for the sake of deer.
In response to those concerns, researchers initiated a study to look at deer and coyote populations from southeastern Canada through the mid-Atlantic region to the Southeast. Using published study data from throughout eastern North America that included fawn mortality, adult doe survival and reproductive rates -- and even the effects of severe winter weather on deer survival and predation -- researchers studied how deer populations responded to changes in predation and hunter harvest.
The research, published in the May issue of the Journal of Wildlife Management, aimed to determine whether managers can compensate for coyote predation of white-tailed deer.
IMAGE: This is an Eastern coyote.

"The concern is that coyotes may be changing the established population dynamics of white-tailed deer herds through increased predation on fawns," said Duane Diefenbach, adjunct professor of wildlife ecology and leader of the Pennsylvania Cooperative Fish and Wildlife Research Unit based at Penn State. "If that's true, then deer managers need to adjust how they make harvest-management decisions, because manipulating doe harvests is typically how wildlife agencies maintain, increase or decrease deer populations."
The study showed that coyote predation -- even at the highest levels reported -- is not significant enough to cause deer populations to decline if doe harvests are reduced. In fact, in most places in North America, continued doe harvest is required to stabilize deer populations.
Diefenbach said the only place in which that might not be true is the Southeast, where wildlife managers have found the highest predation rates on fawns by coyotes. In that region, an average of only one in four fawns survives to three months of age. But that is only in combination with extremely low doe-survival rates.
"However, we couldn't find any published research on adult-doe-survival rates in the Southeast, so it is possible that if doe hunting were stopped, deer populations would stabilize despite the heavy predation."
Mortality of white-tailed deer fawns is significant across the East, Diefenbach noted. Only an average of one in two survives its first three months of life, which is when most mortality occurs. Predation by coyotes, black bears and bobcats accounts for most mortality. Regardless, the number of fawns that survive generally is adequate to sustain nearly all populations.
"Besides predators, the other major source of mortality in fawns is hunting," said Diefenbach. "Thus, reduced hunting can be used to offset mortality from natural predators. Enough fawns survive all sources of mortality that we still need to harvest antlerless deer to maintain stable deer populations. There is little evidence to date that the increase in coyote predation could create a crisis that could not be solved by wildlife managers simply responding with reductions in antlerless deer harvests."

Monday, May 5, 2014

Inbred wolves struggle, moose proliferate at Isle Royale National Park

During their annual Winter Study at Isle Royale National Park, scientists from Michigan Technological University counted nine wolves organized into one breeding pack and a second small group that is a remnant of a formerly breeding pack. 

In the Isle Royale Wolf-Moose Study’s annual report released today, the researchers say that over the past three years, they have tallied the lowest numbers of wolves ever:  nine in 2011–12, eight in 2012–13 and nine in 2013–14.  During the same period, predation rates—the proportion of the moose population killed by wolves—also dropped to the lowest ever recorded, while the number of moose doubled, to approximately 1,050 moose.

Wolves are the only predators of moose on the remote island national park in northwestern Lake Superior.  The moose population has been increasing because wolf predation has been so low.

Wolves are Inbred

 “The poor condition of wolf predation on Isle Royale appears to be caused by inbreeding,” said John Vucetich, director of Michigan Tech’s study of the wolves and moose of Isle Royale. In its 56th year, the research project is the longest continuous predator-prey study in the world.

In the annual report, Vucetich and Rolf Peterson, research professor in Michigan Tech’s School of Forest Resources and Environmental Science and a codirector of the wolf-moose study, document analysis of the DNA of more than 1,000 fecal samples collected from wolves over the past 15 years.  Doing so allowed them to construct a family tree from 1999 to 2013.

That pedigree enabled them to monitor the rate of inbreeding among the wolves.  They found that an immigrant wolf, who eventually came to be known as the Old Gray Guy, came to the island across an ice bridge from Canada in 1997.  He brought a fresh infusion of genes that so dominated the Isle Royale wolves’ weakened gene pool that, by 2008, most of the wolves on the island were descended from the Old Gray Guy.

“This represents a very high standard of evidence that Isle Royale wolves had been suffering from inbreeding prior to the immigrant’s arrival,” says Vucetich.

In the 1960s, ice bridges between Isle Royale and the mainland formed seven out of every 10 winters, the scientists note.  In the past 17 years since the immigrant’s arrival, only two ice bridges have occurred, so the Old Gray Guy’s descendants soon became highly inbred as well. In particular, a large portion of the Old Gray Guy’s descendants were the result of two consecutive generations of close inbreeding.  Of those wolves, all lived short lives, all were dead by 2011, and only one reproduced in this case, a single pup.

“Their short, unproductive lives appear to mark the waning benefits of the genetic rescue event that occurred with the immigrant’s arrival in 1997,” the scientists say in the annual report.

The wolves of Isle Royale were not there when the national park was established in 1940. They are believed to have crossed an ice bridge from Canada in the late 1940s.

Vucetich and Peterson have analyzed data from decades of scientists’ field notes, trying to determine whether the Isle Royale wolves might have benefited from infusions of new genetic material from wolves crossing ice bridges on other occasions in the past.  They found, for example, that a pack of seven or eight wolves, including four black ones, crossed an ice bridge to the island in 1967.  Many of these wolves were still present a year later and may have rejuvenated the population, genetically speaking, about two decades after its founding.

In a paper just published in the journal Conservation Genetics, Peterson, Vucetich, Philip Hedrick of Arizona State University, Jennifer Adams of the University of Idaho and Michigan Tech’s Leah Vucetich report on their study of the effects of this new genetic input.  The Isle Royale study is significant, they write, because “few documented instances of genetic rescue have been observed long enough or in sufficient detail to understand how long one can expect the beneficial effects of genetic rescue to persist.”

But ice bridges are two-way streets. In 1977, researchers observed a pack of wolves chase a pack mate half way to the mainland across an ice bridge. In 2008, the last time an ice bridge formed before this winter, two radio-collared wolves disappeared shortly after the ice bridge formed.  And in late January 2014, an Isle Royale wolf crossed to the mainland on an ice bridge and was found dead as a result of an air pellet wound  near Grand Portage, Minn.

Moose are Proliferating 

Not limited by predation, moose are thriving on Isle Royale. In the past three years, their numbers have doubled; the vegetation that they eat is still plentiful, and the primary factor limiting their growth has probably been the severity of the past two winters, the researchers report.

Unless the next five winters are especially harsh, the moose population is likely to increase dramatically, the researchers say.  Their concern is that, “the likely result would be significant and long-lasting harm to Isle Royale’s forest.”

No Genetic Rescue for Now

The scientists have recommended genetic rescue: bringing a few new wolves to Isle Royale to mitigate the effects of inbreeding. In their new Conservation Genetics paper, the researchers say, “Past gene flow also suggests that human-assisted gene flow is necessary to conserve the ecosystem services associated with predation, since climate warming has reduced the frequency of ice bridges and with it the only opportunity for unassisted gene flow.

Isle Royale National Park recently affirmed that as long as a breeding population of wolves exists on the island there would be no intervention in the near term.

However, the Park Service will begin an expanded planning effort and environmental impact analysis for ecosystem management, focusing on moose and their impacts to the forest, as well as the dynamics between predator and prey.

 “There is time to fully explore all the consequences of such an action,” said Isle Royale National Park Superintendent Phyllis Green.  “Bringing wolves to the island remains an option, however the final decision will be based on the best available sound science, accurate fidelity to the law and long-term public interest.

The annual report is available at

Wednesday, April 23, 2014

Australia's 1 million feral camels

A new study by a University of Exeter researcher has shed light on how an estimated one million-strong population of wild camels thriving in Australia's remote outback have become reviled as pests and culled on a large scale.

Sarah Crowley, of the Environment and Sustainability Institute at the University of Exeter's Penryn Campus, explored the history of the camel in Australia, from their historic role helping to create the country's infrastructure through to their current status as unwelcome "invader."

The deserts of the Australian outback are a notoriously inhospitable environment where few species can survive. But the dromedary camel (Camelus dromedarius) prospers where others perish, eating 80% of native plant species and obtaining much of their water through ingesting this vegetation.

Yet for numerous Australians, particularly ranchers, conservation managers, and increasingly local and national governments, camels are perceived as pests and extreme measures – including shooting them with rifles from helicopters – are being taken to reduce their population.

In her article, published in the journal Anthrozoös, Crowley proposes that today's Australian camels exemplify the idea of "animals out of place" and discusses how they have come to inhabit this precarious position.

She said: "Reports estimate there are upwards of a million free-ranging camels in Australia and predict that this number could double every eight years. As their population burgeons, camels encroach more frequently upon human settlements and agricultural lands, raising their media profile and increasing local animosity toward them."

The camel was first brought to Australia in the 1800s when the country was in the midst of a flurry of colonial activity. The animals were recognized by pioneers as the most appropriate mode of transport for the challenging environment because they require significantly less water, feed on a wider variety of vegetation, and are capable of carrying heavier loads than horses and donkeys.

Camels therefore played a significant role in the establishment of Australia's modern infrastructure, including the laying of the Darwin–Adelaide Overland Telegraph Line and the construction of the Transnational Railway.

Once this infrastructure was in place, however, and motorized transport became increasingly widespread, camels were no longer indispensable. In the early part of the 20th century they rapidly lost their economic value and their displaced handlers either shot their wards or released them into the outback where, quite discreetly, they thrived.

It was not until the 1980s that surveys hinted at the true extent of their numbers, and only in 2001 that reports of damage caused by camels were brought to the general populace.

Camels are not the most dainty of creatures. Dromedaries are on average six feet tall at the shoulder, rendering cattle fencing no particular obstacle to their movement. By some accounts, camels may not even see small fences and consequently walk straight through them.

Groups of camels arriving on agricultural properties and settlements in Australia, normally in times of severe drought, can also cause significant damage in their search for water.

In 2009, a large-scale culling operation began. There were objections from animal welfare groups and some landowners who were concerned that the method of culling from helicopters, leaving the bodies to waste, is inhumane. Most objectors, however, were primarily concerned that culling is economically wasteful and felt that the camels should be mustered for slaughter or export.

There are also concerns regarding the global environment, as camels may contribute to the desertification of the Australian landscape. They are also ruminants and thus produce methane, adding to Australia's carbon emissions. Crowley does not question the accuracy or significance of this, but points out that the environmental impacts of even 1,000,000 feral camels pales in comparison to that of the 28,500,000 cattle currently residing in the country. Still, when dust storms gathered over Sydney in 2009, media reports implied that the camel was the culprit.

Camels have in recent times been referred to in Australia as "humped pests," "a plague," a "real danger" and "menacing," and their actions described as "ravaging" and "marauding."

Crowley added: "These terms show how camels have suddenly been attributed agency – their crossing of acceptable human boundaries is somehow deemed purposeful and rebellious. These accusations lie in stark contrast to the praise laid upon those dromedaries who assisted colonists in the exploration and establishment of modern Australia, and highlight how temporal changes in culture—specifically, shifting economic and environmental values—have affected human interpretations of the presence, purpose, and even behavior of Australian camels."

Thursday, March 6, 2014

Yosemite bears and human food: Study reveals changing diets over past century

Management strategies implemented since 1999 have successfully limited the availability of human food to black bears in Yosemite, but problems remain

Black bears in Yosemite National Park and elsewhere are notorious for seeking out human food, even breaking into cars and cabins for it. A new study reveals just how much human food has contributed to the diets of Yosemite bears over the past century.

Researchers at the University of California, Santa Cruz, were able to estimate the proportion of human-derived food in bears' diets by analyzing chemical isotopes in hair and bone samples. The results, published in the March issue of Frontiers in Ecology and the Environment, show how bears' diets have changed over the years as the National Park Service took different approaches to managing bears and people in Yosemite.

"Yosemite has a rich history of bear management practices as a result of shifting goals over the years," said Jack Hopkins, lead author of the paper and a research fellow at UC Santa Cruz. "What we found was that the diets of bears changed dramatically after 1999, when the park got funding to implement a proactive management strategy to keep human food off the landscape."

That funding has been used primarily to buy bear-resistant food-storage containers and increase enforcement of their use, hire more staff to manage problem bears, and establish a "bear team" to increase visitor compliance with rules for storing food in areas such as campgrounds and hotels. The study, which focused on bears that had learned to eat human food or food waste, found that the proportion of human foods in their diets decreased by about 63 percent after the new strategies were implemented. Unfortunately, according to Hopkins, once a bear gets used to eating human food it will continue looking for it, and even when visitor compliance is high, there will always be a few people who make the mistake of leaving their food where bears can get it.

Hopkins, who worked as a biologist in Yosemite National Park for several years, conducted the study as a graduate student at Montana State University. He teamed up with coauthor Paul Koch, a professor of Earth sciences and dean of physical and biological sciences at UC Santa Cruz, to do the isotope analysis of hair and bone samples. Contemporary hair samples were collected during bear management actions and from barbed-wire hair snares deployed throughout Yosemite. Historical samples were obtained from museum collections.

"This study shows the power of using museum specimens and archived historical material to reconstruct the ecology of a species and to answer pressing management questions," Koch said. "The remarkable thing is that the bears that eat human food are now back to the same level of dumpster diving as in 1915, despite the fact that there are now millions of visitors in Yosemite every year and presumably a lot more garbage."

Yosemite National Park was established in 1890, and Hopkins obtained samples from bears killed between 1915 and 1919 to represent the earliest time period. In those early years, bears were attracted to garbage dumps in the park and were often killed when they became a nuisance. Visitors liked to see bears, however, and in 1923 the park began intentionally feeding bears where visitors could watch them. The last artificial feeding area closed in 1971. There was also a fish hatchery in Yosemite Valley, from 1927 to 1956, where bears once helped themselves to fresh trout from the holding tanks. But closing the hatchery and the feeding areas didn't stop bears from eating human food.

"The bears just went back to the campgrounds and hotels and continued to find human food," Hopkins said.

The average figures for the proportion of human food in bear diets during the four time periods in the study were 13 percent for the period from 1915 to 1919; 27 percent for 1928 to 1939; 35 percent for 1975 to 1985; and 13 percent again for 2001 to 2007.

These results are based on a kind of chemical forensics in which Koch's lab specializes. Isotopic analysis of an animal's tissues can yield clues to its diet because of natural variability in the abundance of rare isotopes of elements such as carbon and nitrogen. Isotope ratios (the ratio of carbon-13 to carbon-12, for example) are different in human foods than in the wild plants and animals that black bears naturally eat in Yosemite, partly due to the large amounts of meat and corn-based foods in our diets.

In order to analyze the data from Yosemite bears that ate a mixture of human and natural foods, Hopkins had to get samples from bears that did not eat any human food, and he had to track down samples of the non-native trout that had been raised in the hatchery. He also needed data representing a 100 percent human food diet, for which he turned to the Smithsonian Institution for samples of human hair from different periods over the past century.

"He searched far and wide to get the collection of samples we analyzed, and that collection made the study powerful enough to answer the question of how management practices affect bear diets," Koch said.

According to Hopkins, the key to managing bear problems is to prevent bears from becoming conditioned to eat human food in the first place. He has done other studies using genetic analysis to show that the offspring of bears that eat human food end up having the same foraging behaviors as their mothers. And when problem bears are relocated away from human food sources, they eventually return and continue seeking human food until they are killed, often by management staff.

"People like to see bears, and they don't like to hear about bears being killed. But the bears they often see in visitor-use areas like Yosemite Valley are the ones that are conditioned to eat human food, and those are the ones that become problems and have to be killed," Hopkins said.

Cougars Are Re-Populating their Historical Range

American mountain lions, or cougars, are remerging in areas of the United States, reversing 100 years of decline. The evidence, published in The Journal of Wildlife Management, raises new conservation questions, such as how humans can live alongside the returning predators.

The reintroduction of mountain lions across the mid-western United States has made species management an urgent area of research for conservationists. A report in the Wildlife Society Bulletin explores the fatal cost of human interaction with cougars and asks what state agencies can do to protect both species.

Cougars (Puma concolor) are slowly recolonizing their historic habitats, including the Black Hills of South Dakota, but since they’ve been away, the land has become crossed with roads and home to many human communities.

The authors studied 31 cougars, captured between 1999 and 2005. Over the course of 1,570 days, 12 mortalities were recorded. Despite being protected from hunting nearly 62% of cougar deaths were attributed to human influences.

A further 85 dead cougars were analyzed during the study, with collisions being the most common cause of death. Snaring and illegal hunting were also identified as causes.

“The cougar population declined dramatically from 1900, due to both hunting, and a lack of prey, leaving the remaining population isolated to the American west,” said Michelle LaRue from the University of Minnesota. “Here we present the hard evidence that the western population has spread, with cougar populations re-establishing across the Midwest.”

Three main cougar populations exist in the Midwest centered around The Black Hills in South Dakota, however, cougars are venturing far outside of this range. One male cougar from the Black Hills was found to have traveled 2,900 kilometers through Minnesota, Wisconsin and New York, before ending up in Connecticut.

“While the distance the Connecticut cougar traveled was rare, we found that cougars are roaming long distances and are moving back into portions of their historical range across the Midwest ”, said LaRue. “Our study took in over 3,200,000 Km² of territory, confirming the presence of Cougars from Texas, Arkansas and Nebraska, to the Canadian provinces of Ontario and Manitoba.”

Working alongside scientists from Southern Illinois University Carbondale and The Cougar Network, LaRue and Principal Investigator Dr. Clay Nielsen analyzed cougar sightings which have been reported since the 1990’s to characterize confirmed sightings over time, assess habitat suitability and confirm where cougar populations are being re-established.

Aside from confirmed sightings, the team’s evidence included carcasses, tracks, photos, video, DNA evidence and cases of attacks on livestock across 14 states and provinces of North America. Only sightings which were verified by wildlife professionals were included, while sightings of animals known to be released from captivity were excluded to ensure only natural repopulation was analyzed.

The results reveal 178 cougar confirmations in the Midwest with the number of confirmations steadily increasing between 1990 and 2008. Approximately 62% of confirmed sightings took place within 20km of habitat that would be considered suitable for cougar populations.

When cougar carcasses were recovered 76% were found to be male. As the Connecticut example shows, males are capable of traveling long distances and this finding suggests males are leading a stepping-stone dispersal of the cougar population.

“This evidence helps to confirm that cougars are re-colonizing their historical range and reveals that sightings have increased over the past two decades,” concluded LaRue. “The question now is how the public will respond after living without large carnivores for a century. We believe public awareness campaigns and conservation strategies are required across these states, such as the Mountain Lion response plans already in place in Nebraska and Missouri.”

Sunday, February 2, 2014

Teaching young wolves new tricks

Although wolves and dogs are closely related, they show some striking differences. Scientists from the Messerli Research Institute at the University of Veterinary Medicine, Vienna have undertaken experiments that suggest that wolves observe one another more closely than dogs and so are better at learning from one another. The scientists believe that cooperation among wolves is the basis of the understanding between dogs and humans. Their findings have been published in the online journal PLOS ONE.

Wolves were domesticated more than 15,000 years ago and it is widely assumed that the ability of domestic dogs to form close relationships with humans stems from changes during the domestication process. But the effects of domestication on the interactions between the animals have not received much attention. The point has been addressed by Friederike Range and Zsófia Virányi, two members of the University of Veterinary Medicine, Vienna (Vetmeduni Vienna) who work at the Wolf Science Center (WSC) in Ernstbrunn, Niederösterreich.

Wolves copy other wolves solving problems

The scientists found that wolves are considerably better than dogs at opening a container, providing they have previously watched another animal do so. Their study involved 14 wolves and 15 mongrel dogs, all about six months old, hand-reared and kept in packs. Each animal was allowed to observe one of two situations in which a trained dog opened a wooden box, either with its mouth or with its paw, to gain access to a food reward. Surprisingly, all of the wolves managed to open the box after watching a dog solve the puzzle, while only four of the dogs managed to do so. Wolves more frequently opened the box using the method they had observed, whereas the dogs appeared to choose randomly whether to use their mouth or their paw.

Watch closely …

To exclude the possibility that six-month old dogs fail the experiment because of a delayed physical or cognitive development, the researchers repeated the test after nine months. The dogs proved no more adept at opening the box than they were at a younger age. Another possible explanation for the wolves’ apparent superiority at learning is that wolves might simply be better than dogs at solving such problems. To test this idea, the researchers examined the animals’ ability to open a box without prior demonstration by a dog. They found that the wolves were rarely successful. “Their problem-solving capability really seems to be based on the observation of a dog performing the task,” says Range. "The wolves watched the dog very closely and were able to apply their new knowledge to solve the problem. Their skill at copying probably relates to the fact that wolves are more dependent on cooperation with conspecifics than dogs are and therefore pay more attention to the actions of their partners.”

The researchers think that it is likely that the dog-human cooperation originated from cooperation between wolves. During the process of domestication, dogs have become able to accept humans as social partners and thus have adapted their social skills to include interactions with them, concomitantly losing the ability to learn by watching other dogs.

Friday, January 10, 2014

Study Shows Large Carnivore Numbers and Range Declining Worldwide

New research co-written by University of Montana scientists finds steep declines in the worldwide populations and habitat range of 31 large carnivore species. The analysis, published Jan. 9 in Science, shows that 77 percent of the studied species – including tiger, lion, dingo and puma – are decreasing in number.

Associate Professor of ungulate habitat Mark Hebblewhite and John J. Craighead Chair and Professor of Wildlife Conservation Joel Berger, both of the UM College of Forestry and Conservation, co-wrote the study with scientists from Oregon State University, the University of California, Yellowstone National Park, University of Washington, Yale University and researchers in Australia, Italy and Sweden.

The study shows that 17 of the species occupy less than half their normal habitat range. These changes have serious environmental consequences, the authors argue.

Large carnivores are vulnerable to extinction because of their low population densities and their need to roam widely to search for food. These animals are essential to the health of an ecosystem and also provide social and economic benefits for humans.

“Ecosystems depend on large carnivores to control herbivores like deer and populations of smaller carnivores,” Hebblewhite said. “We suggest that losing a population of large carnivore doesn’t just impact that species, but an entire landscape.”

Further declines in the populations of these large carnivores will lead to changes in plant species diversity, biomass and productivity. These vegetation changes will have a wide-ranging influence on other species. Carnivore losses also will impact wildlife disease dynamics, wildfire and carbon sequestration.

Hebblewhite points to several success stories, like the reintroduction of gray wolves to Yellowstone National Park, potential delisting of grizzly bears in the Northern Rockies and the Global Tiger Initiative, to demonstrate that reintroducing and recovering carnivores has many benefits.

In Yellowstone National Park, the return of wolves has contributed to aspen and willow restoration, stabilized carrion availability for scavengers like grizzly bears and magpies, and has increased carbon storage by allowing plants to flourish.

But beyond the large carnivore conservation successes of the Northern Rockies, carnivore populations are declining worldwide, especially in Asia and Africa. These declines are mostly due to habitat loss, overhunting and trade of endangered wildlife parts.

“We haven’t yet untangled all the ways in which these large carnivore population declines will play out in the future – but we know they will have profound ecosystem impacts,” Berger said.

Hebblewhite and Berger agree that lessons learned from carnivore reintroduction in the Northern Rockies can serve as a model to the rest of the world. At UM, training international students in large carnivore conservation is a key focus.

Wildlife biology doctoral student Tshering Tempa currently applies some of these advances in carnivore science and conservation to Bengal tigers in his home country of Bhutan.

“Conservation has to be underpinned by sound science,” Tempa said. “In Bhutan, there is a real chance of ensuring that large carnivores and their prey persist perpetually. I am applying the skills I have learned at UM to contribute toward this.”

With looming threats to global distributions of large carnivores, Hebblewhite concludes that more science is needed to better understand all the benefits of every large carnivore species, which human activities are most in conflict with large carnivores, and what management activities will have the most impact on sustaining large carnivore populations.

Thursday, January 9, 2014

Paper predicts a future without carnivores would be truly scary

A fascinating paper released today from a team of leading scientists, including Dr. Joel Berger of the Wildlife Conservation Society and University of Montana, reports on the current status of large carnivores and the ecological roles they play in regulating ecosystems worldwide, and finds that a world without these species is certainly scarier than a world with them.

From sea otters that keep sea urchins in check and enable the rise of kelp beds thus increasing the productivity in inland coastal areas to pumas that mediate the browsing of mule deer and thus enhance the growth and reproduction of woody plants, the scientists profile seven of the 31 largest species of the order Carnivora and their well-studied ecological effects.

The paper, "Status and Ecological Effects of the World's Largest Carnivores," appears in the January 10, 2014 issue of the journal, Science. More than 100 published studies were reviewed to offer a comprehensive look at the state of carnivores and their impacts on the world today.

WCS Executive Vice President of Conservation and Science John Robinson said, "This important paper explores how carnivores regulate the structure and functioning of ecosystems and what happens when they are lost. For many people, it will be an eye-opener and hopefully bring about a change in attitudes and a deeper appreciation of these key species. Around the world, WCS continues to work to preserve the ecosystems that are vital to carnivores and to understand the critical benefits they provide to both wildlife and people."

Among their many impacts, carnivores are a benefit to ecotourism. Yellowstone National Park's restored wolf population, for example, brings in tens of millions of dollars in tourist revenue each year. And when wolves are absent, the effect on natural selection is dramatic. "In Badlands National Park, we have observed bison born with deformed hooves or portions of their legs missing," said WCS Conservation Scientist and author of The Better to Eat You With, Joel Berger. "Historically, these bison would have been selected out for predation by wolves, contributing to the overall health of the herd. Today, without wolves, these bison survive and reproduce. This is not the way healthy ecosystems are maintained."

The ecological services provided by carnivores are multifarious. Carnivores control herbivores to the relief of plants, mitigate global warming, enhance biodiversity, restore rivers and streams, and regulate wildlife disease and livestock disease spillover.

However, many of the largest carnivores are listed as threatened on the International Union for the Conservation of Nature (IUCN) Red List, and most are still declining in number. These 'top or apex predators' have one great competitor: humans.

The authors note that "large-carnivore population declines are typically precipitated by multiple, and sometimes concurrent, human threats including habitat loss and degradation, persecution, utilization (such as for traditional medicine, trophy hunting or furs), and depletion of prey."

Oregon State University professor and lead author of the paper, William J. Ripple said, "Globally, the ranges of carnivores are collapsing and many of these species are at risk of either local or complete extinction. It is ironic that large carnivores are disappearing just as we are learning about their important ecological and economic effects."

Looking to the future, the scientists expect that the loss of apex predators will bring degradation to ecosystems that include reductions in plant diversity, biomass and productivity as well as wide-ranging impacts to other species. Greater rates of herbivory and concurrent decline of plant species may hasten global warming and desertification.

Critical to living with carnivores, the scientists conclude, is an understanding of the benefits they provide and where human/predator conflicts arise. Linking policy issues facing people such as population growth, meat consumption and exploitation of wild prey, livestock production, greenhouse gas emissions, food security, deforestation and desertification, and water quality/quantity with carnivore conservation is a necessary step toward coexistence.