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."

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.”

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.

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.

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.

Plan to delist gray wolf endangers other threatened species, researchers find

The federal government's proposal to discontinue protection for the gray wolf across the United States could have the unintended consequence of endangering other species, researchers say.

As written, scientists assert, the proposed rule would set a precedent allowing the U.S. Fish and Wildlife Service (FWS) to declare habitat unsuitable for an endangered animal because a threat exists on the land – the exact opposite of the service's mandate to impose regulations that reduce threats against imperiled species.

The FWS has "conflated threats with habitat suitability" by stating that U.S. land currently unoccupied by wolves – most of the country that historically served as wolf habitat – is now unsuitable because humans living in those regions won't tolerate the animals, the lead scientist said. This claim runs counter to existing research, which the service did not cite in its explanation of the rule.

"The Fish and Wildlife Service is supposed to detail what the threats are and if they're substantial enough, they're supposed to list a species and put in place policies to mitigate the threats," said Jeremy Bruskotter, associate professor in The Ohio State University's School of Environment and Natural Resources and lead author of the paper.

"Here, they're saying that they recognize the threat of human intolerance and instead of mitigating the threat, they're just going to say the land is unsuitable."

Were this rule to stand, he said, "Anytime the U.S. Fish and Wildlife Service finds that something is in the way of a species' recovery, they can just say the habitat is unsuitable for the species and disregard the threat altogether."

FWS proposed removing the gray wolf (Canis lupus) from the list of threatened and endangered species in June. The rule covers most of the continental United States where wolves historically existed, before being exterminated by people in the late 19th and early 20th centuries. Public comments closed Dec. 17, and will be analyzed and considered before the service issues a final rule.

The critique is published online in the journal Conservation Letters.

Congress passed the Endangered Species Act in 1973. The act expanded on previous legislation by providing for the protection of any species in danger of or threatened with extinction throughout all or a significant portion of its range.

The act's language is critical to what follows: In determining whether a species has recovered, the law requires FWS to declare it is no longer endangered in all or a "significant portion of its range." The gray wolf has recovered in the northern Rockies and upper Great Lakes.

The proposed rule, however, discounts the other 85 percent of the wolf's historic range, which stretches across northern states from the west coast through New England and as far east as mid-Texas in the southern half of the country.

"So what the service is saying is that wolves are going to be called recovered in most of the United States despite the fact that very few wolves live outside these two recovered areas," Bruskotter said. "Wherever they are now, that's their range – which means taking the historic and geographic component out of the listing process."

He and colleagues suggest that this practice not only disregards the law, but "specifically creates incentive to destroy habitat in advance of a listing and do things that aren't good for endangered species."

The law also requires the service to consider the "best available science" in assessing whether threats have eased and a species is recovered. Instead of citing the dozens of studies that suggest human support for wolf restoration is high, the service simply ignored this research and claimed that these areas are unsuitable because of human intolerance. When federal protection is lifted, species management falls to the states.

"That process is not the best available science," Bruskotter said.

Bruskotter acknowledged that FWS is under enormous pressure from the opposing sides of a highly contentious fight about wolves: hunters and livestock producers on one side and wildlife advocates on the other. But that pressure doesn't relieve the service of its duty to act on behalf of endangered species as the law requires, he said.

"The law is supposed to help the protected species, not just describe the threats to that species. But to construct this delisting rule, they've had to interpret policy and science in every case in a way that either disregards threats to wolves, or treats them as insurmountable," he said. "They're doing the opposite of what the act requires."