Blood does not buy goodwill

In the paper published Guillaume Chapron and Adrian treves in Proceedings B of the Royal Society (Blood does not buy goodwill: allowing culling increases poaching of a large carnivore), the authors looked at whether removing protection for large carnivores would decrease illegal hunting. This idea is supported by many governments. Does it work as expected? Find out by watching this video and by reading the paper available at http://rspb.royalsocietypublishing.org/content/283/1830/20152939.

Abstract of the paper:

Quantifying environmental crime and the effectiveness of policy interventions is difficult because perpetrators typically conceal evidence. To prevent illegal uses of natural resources, such as poaching endangered species, governments have advocated granting policy flexibility to local authorities by liberalizing culling or hunting of large carnivores. We present the first quantitative evaluation of the hypothesis that liberalizing culling will reduce poaching and improve population status of an endangered carnivore. We show that allowing wolf (Canis lupus) culling was substantially more likely to increase poaching than reduce it. Replicated, quasi-experimental changes in wolf policies in Wisconsin and Michigan, USA, revealed that a repeated policy signal to allow state culling triggered repeated slowdowns in wolf population growth, irrespective of the policy implementation measured as the number of wolves killed. The most likely explanation for these slowdowns was poaching and alternative explanations found no support. When the government kills a protected species, the perceived value of each individual of that species may decline; so liberalizing wolf culling may have sent a negative message about the value of wolves or acceptability of poaching. Our results suggest that granting management flexibility for endangered species to address illegal behaviour may instead promote such behaviour.

Does hunting impact carnivore recruitment?

“Recruitment in a social carnivore before and after harvest” is the title of a recent paper published on the Journal Animal Conservation of the Zoological Society of London that shows collateral impacts of harvesting wolves:

“We attributed just 18–38% of pup mortality directly to harvest and suggest that there are indirect effects of harvest on recruitment that may be associated with changes in group size and structure. Models that do not include both direct and indirect effects of harvest on recruitment may underestimate the potential impact of harvest on population growth in social species.”

The article does not have open access and it is available HERE but you can read it in this LINK.

Other recommended reads: http://www.klamathconservation.org/science_blog/conservation/?p=192

Lion vs. Warthog

Original Source: Daily Mail

This is the moment a warthog stepped into the path of a hungry lion and then became its prey. The incredible pictures show the warthog step into the lion’s den, but it was only ever going to end one way, as the predator then leaps out with brute force to capture the animal.

The lion then goes on to devour the wild pig, proving his status as top of the animal food chain.

The stunning images were caught on camera by photographer Dr Trix Jonker, at the Addo Elephant Park in the Eastern Cape province of South Africa.

Dr Jonker revealed she almost missed the moment as the warthog had a lucky escape first of all after it accidentally woke a sleeping lioness, but foolishly walked back in front of the lions and this time was not so lucky. But she managed to capture the action at the perfect minute. She added: “After the warthog escaped, I thought the action was over. But the warthog went back in a circle and went back on the same path as before, straight back into the lions.”

She said: “It was getting late and the gates were closing in an hour. I looked away and when I looked back I saw the warthog coming straight towards some resting lions. By this time, a male lion had woken up and was sat up straight trying to see what the commotion was. He saw the warthog coming and went straight into the attack position. This was when I had my camera poised as I knew this time something was going to happen. At one stage there was only this big dust cloud and I could not see what was happening.”

“He stayed like that for quite a while then lifted the warthog into the air and started dragging it away. I couldn’t believe how tough the warthog was, and was absolutely stunned by what I saw that afternoon. It’s amazing I managed to capture it on camera.”

Sources:
http://blog.africageographic.com/africa-geographic-blog/wildlife/wildlife-and-nature/lion-vs-warthog/
http://www.dailymail.co.uk/news/article-2611074/Lion-v-Warthog-The-stunning-moment-warthog-steps-path-hungry-lion-Spoiler-alert-lion-wins.html

Wolves are not the Cause of Elk Population Decline in Wyoming

by Alex Robinson

Any hunter who’s spent time in wolf country can attest to the predators’ influence. We see wolf tracks, find old kills, and often times we spot fewer game animals. But exactly how wolves affect big-game populations is still greatly unknown. Yeah, wolves eat elk. But, do they kill mostly adults or calves? Do they eat enough elk to wipe out a whole herd? Do they pressure elk into hiding in the timber or force them off their feeding patterns? Are wolves even one of the main factors in elk population dynamics?

New research from the Wyoming Cooperative Fish and Wildlife Research Unit at the University of Wyoming is starting to shed light on some of these questions. After three years of studying the Clark’s Fork elk herd (about 5,000 animals) in northwest Wyoming, lead researcher Arthur Middleton found that wolves might not be as detrimental to elk populations as many outdoorsmen think.

His research shows that the Clark’s Fork herd’s fate is based on a complex set of variables including habitat, weather, hunting, bears, and wolves.

“There’s a pretty popular notion that elk are always responding to wolves. And that’s a fairly logical perception because wolves are always hunting elk … But wolves hunt an elk population. That [hunting pressure] doesn’t always affect individual animals.”

Photo: Elk traveling across their winter range in Yellowstone National Park, USGS.

The Study
Middleton and a coalition of biologists GPS collared wolves and elk west of Cody, Wyoming in and around Yellowstone National park. In a study area of about 1 million acres, they monitored interactions between predator and prey. Over three years they observed the animals in January, February, and March – when wolves typically put the most stress on elk. The study was funded by a variety of organizations and agencies including Rocky Mountain Elk Foundation, Boone & Crockett Club, U.S. Fish and Wildlife Service, and Safari Club International.

The researchers set out to test the theory that wolves were responsible for decreasing elk populations in ways besides direct predation. In other words, they wanted to find out if pressure from wolves was running elk out of their regular feeding patterns and keeping cows from putting on enough body fat to rear calves in the spring.

The research started at a critical time for the Clark’s Fork herd. Calf-to-cow ratios in the migratory herd started dropping in the mid-90s, about the same time wolves were introduced. Those ratios have remained low since 2002 and overall elk numbers decreased. Middleton found about 15 calves to 100 elk in the migratory Clark’s Fork herd. In the resident herd, the ratio was about 35 calves per 100 elk.

Hunters and wildlife managers were alarmed by the drop in elk numbers. Doug McWhiter, a Wyoming Fish and Game biologist who manages the area, said elk numbers are stable now, but hunting opportunities had to be cut. Cow tags were reduced and hunting units in the area were switched from general over-the-counter licenses to limited quota in 2010. Hunter opportunity was reduced by 50 to 75 percent, says McWhiter who helped with Middleton’s research.

“We can maintain these elk numbers but we had to severely limit hunting opportunity to do that,” he says. “That in itself is difficult for people to understand.”

Photo: The Agate wolf pack in a stand-off with a bull in Yellowstone, NPS.

The Findings
Middleton and his crew found that a new wolf pack does not mean certain doom for an elk herd. In fact, elk have adapted to living with wolves.

“From my time in the field, I can say that most days in the life of a cow elk are pretty boring,” Middleton says. On average, elk encountered wolves once every 9 days. The highest wolf-encounter rate for any individual elk was once every four days. And, even though elk were encountering wolves, they weren’t overly stressed or run to starvation.

“We didn’t see any reduction in rate of feeding and we didn’t see them shift into timber. Those two behaviors were said to be [metabolically] costly, but we just didn’t see [the elk reacting that way,]” Middleton says.

Elk did move slightly more when wolves were within 1 kilometer, but not by much – they only traveled an extra 30 meters per hour when wolves were in the area.

The researchers also found that the number of wolf encounters had no impact on the amount of elk body fat. Body fat is a critical measurement for cows’ ability to rear calves.

So if the wolf-hunting-pressure theory was busted, what was happening to the Clark Fork’s herd?

Middleton says it comes down to habitat. The area has suffered a 20-year decline in habitat across the herd’s summer range. If an elk can’t put on enough body fat in the summer and fall, then it will struggle through the winter, regardless of predators, Middleton says.

“We looked at a suite of factors that could explain late-winter body fat and the only thing that did explain it was autumn body fat. In other words, whatever they get over the summer determines where they end up in winter,” he says.

Of course, wolf predation does affect overall elk numbers, but in a separate study Middleton found that wolves weren’t even the top calf predators. He found that bears typically take out more elk calves than wolves do. During a June monitoring period grizzlies killed an elk calf every two to four days and black bears killed a calf every four to eight days.

Photo: Wolf on an elk kill in Yellowstone, PLOS Biology.

Backcountry Observations
Collecting data that shows an elk herd can thrive in wolf country and then getting people to actually believe that data are two different challenges. Hunters and outfitters who have spent their lives in the backcountry – before and after the wolf reintroduction – have already made plenty of their own observations.

Tim Doud, owner of Bliss Creek Outfitters out of Cody, says the elk decline goes hand-in-hand with the wolf reintroduction. Clear and simple.

“The elk population numbers have certainty decreased and it is because of the wolves. That’s the only reason in my eyes,” he says. “Now I’m not anti-wolf. I don’t think they should be wiped out or anything like that. But we do need to hunt more of them. Most people don’t see what I see. They don’t see the horrific, suffering death of an elk whose hindquarters have been chewed away and can only lay there and die slowly. That’s a real shame. Most people … go to Yellowstone to see the pretty dogs.”

Ron Lineberger owns Butte Creek Outfitters with his wife Theresa and guides elk hunters in the Wyoming backcountry. Over the years he’s seen elk behavior change, and in many ways his observations match Middleton’s research.

“Elk behavior has totally changed, but the elk are not gone. Everyone loves to blame the wolf because it’s easy … [Wolves] did change the dynamic for the environment and they’ve changed the way a lot of animals have evolved. It has led to a bit of catastrophic natural adaptation…

“There has been a succession of fires, which destroyed natural elk habitat. Grizzly bear numbers have gone up and the elk have moved to survive. They have moved to more agricultural and human habitat areas. It’s not just the wolf that’s caused the change. People just look to put the blame on one thing. Yes, elk have moved to areas that haven’t seen elk for 200 years. But there are large portions of healthy elk populations that have moved to private land, which makes them unhuntable … Think of it this way: the elk are picking their poison. Either deal with hunters in the low country for 6 weeks, or stay in the high country and deal with wolves and bears year round.”

The takeaway? Adapting to environmental changes is key to the success of a species, and an elk hunter.

“The hunter has to adapt as well,” Lineberger says. “Hunting elk also relies on a lot of factors that we have no control over. The fact that they have become more alert thanks to the wolves, certainly makes it tougher, but hunters must adapt to that. We are no different than any other animal. We must adapt to survive.”

Source: http://www.outdoorlife.com/blogs/newshound/2013/06/study-wolves-not-cause-wyoming-elk-decline

British Columbia’s hunting quotas are not based on science

Ignacio Yufera/FLPA

Data on grizzly bears in British Columbia are not reliable enough to justify higher hunting quotas, researchers argue.

As the Canadian province of British Columbia prepares to open its annual grizzly-bear hunting season, conservation scientists are protesting the provincial government’s decision to expand the number of animals that can be killed.

British Columbia officials estimate that there are 15,000 grizzlies (Ursos arctos horribilis) in the province, making up roughly one-quarter of the North American population. Although some sub-populations are declining and the species is listed as of “special concern” by some environmental bodies, it is not listed under Canada’s Species at Risk Act, which would afford the bears government protection. Citing the recovery of some sub-populations, the government has opened up previously closed areas to hunting and increased the number of hunting tags for bear kills from about 1,700 to 1,800.

But some researchers say that the original limits for the bear hunt were set too high for sustainable management, and the revised quota could exacerbate that problem.

“Wildlife management wraps itself in science and presents itself as being scientific, but really, when you examine it, it isn’t true,” says Paul Paquet, a biologist at the Raincoast Conservation Foundation in Sidney and the University of Victoria, Canada, and a co-author of a letter in Science this week¹ making the complaint.

The allowance is much higher than the actual kill rate — about 300 grizzlies are taken by hunters each year in the province, mainly as trophies — but Paquet and other conservation scientists argue that it is still possible that grizzly bears are dying at a rate that is too high for sub-populations to support.

“They’re going in the wrong direction,” says Kyle Artelle, a conservation ecologist at Simon Fraser University in Burnaby, Canada, and a co-author of the letter.

Last year, Artelle and his colleagues reported that it is common for more bears to die than the government’s stated “maximum allowable mortality rate” of 6% of the population per year². In more than half of British Columbia’s 42 huntable regions the number of deaths from ‘unnatural causes’, such as road accidents and hunting, exceeded that target for at least one three-year period between 2001–2011. The researchers conclude that reducing the risk of such ‘overkills’ to a low level would require an 81% reduction in the target. “Because these are long-lived, slow-reproducing populations, they don’t necessarily recover from overkill,” says Paquet.

Garth Mowat a biologist with British Columbia’s ministry of forests, lands and natural-resource operations, counters that the 6% target was never meant to be a hard cap. “We choose a conservative number because we know we’re going to go over it occasionally,” he says. “I think [the quotas] are as good as we can do with the data we have, and based on all that, the hunt is sustainable.”

Artelle disagrees that a 6% allowable mortality figure is conservative. He points out that other studies have come up with estimates of 0–5% for British Columbia². And although a December 2013 study by Mowat and his colleagues concluded that there are about 13,000–14,000 grizzlies in the province³, Paquet says that the number could be as low as 8,000 or higher than 15,000. The data behind such estimates, which come from sources ranging from aerial surveys to traps that snag the hair of passing bears, are often sparse or outdated, he says. “In many cases [the population estimate] will be based on assumptions that are maybe 10 years old. None of this is easy, obviously. But we need to take account of the uncertainties,” he says.

The Convention on International Trade in Endangered Species of Wild Fauna and Flora has banned the import of products from grizzly hunts in British Columbia to Europe, citing the province’s failure to implement a grizzly bear strategy it proposed in 2003, which called for better population assessments, among other things.

“In the United States, there’s recourse to courts,” says Paquet, who notes that there are frequent legal battles over US hunting and the country’s Endangered Species Act. “In Canada there’s essentially no appeal.”

Nature doi:10.1038/nature.2014.14914

1. Artelle, K. A., Reynolds, J. D., Paquet, P. C. & Darimont, C. T. Science 343, 1311 (2014). Show context
2. Artelle, K. A. et al. PLoS ONE 8, e78041 (2013). Show context
3. Mowat, G., Heard, D. C. & Schwarz, C. J. PLoS ONE 8, e82757 (2013). Show context

Source: http://www.nature.com/news/canadian-grizzly-bears-face-expanded-hunt-1.14914

Overkill – trophy hunting slams BC’s Grizzly bears

In BC, Canada, a surge in trophy hunting may be reducing Grizzly bear populations, writes Anna Taylor. A new study finds evidence of serious Grizzly bear ‘overkill’ from multiple causes of mortality – in which trophy hunting is a big contributor.

In one area, trophy hunters killed 24 more grizzlies than the quota allowed, and overhunting was particularly prevalent for female bears that are critical for a sustainable population.

The British Columbia Government claims that the quotas they set for the number of Grizzly bears allowed to be killed each year ensure that hunting practices are sustainable.

But a new study into the management of Grizzly bears in BC, published in the open-access journalPLoS ONE, finds that so-called ‘overkills’ occurred in half the Grizzly bear populations.

The findings are also relevant to the USA andproposals to strip Grizzly bears of federal protection under the Endangered Species Act.

Worrying discoveries

Scientists set out to test the BC Government’s claim and made some worrying discoveries. Kyle Artelle, from Simon Fraser University and lead author of the study, explains:

“We tested how well managers were able to maintain grizzly bear kill rates below limits their own biologists have deemed sustainable.

“This assessment was straightforward – for a given population and across three management periods we simply compared the number of bears the province said could sustainably die (‘mortality limits’) by human-caused kills to the number that actually died.”

Too many unknowns

To do this his team looked at three key quantities that carry considerable uncertainty: population estimates; population growth rates; and the number of unreported human-caused bears deaths, including poaching kills.

The population growth rates are key in this, says Artelle – also a wildlife scientist with the Raincoast Conservation Foundation – because they are used to estimate how many bears can be killed in a given population without causing declines.

“You can imagine how these might contribute to undetected overkills – for instance if you assume a population is a given size and set your hunting quotas accordingly, if it turns out the population is actually smaller, then the hunting quotas you set would have been too high.

“We addressed this quantitatively and found that, based on unaddressed uncertainty, overkill rate might indeed be considerably higher than previously assumed.”

They found that overkills – defined as taking place when the number of kills exceeds the mortality limits that are set by the government – occurred in half of the populations that are open to hunting. Artelle says that hunting is adding to the other problems faced by the bears:

“Although these were caused by a mix of hunting and other human-caused kills – road and rail accidents, self-defence kills, ‘problem bear’ kills and so on – we found that almost all overkills could have been prevented by reducing or eliminating the hunt.”

Hunting quotas breached

In one area, trophy hunters killed 24 more grizzlies than the quota allowed, and overhunting was particularly prevalent for female bears that are critical for a sustainable population. This shows that guidelines that encourage hunters to avoid females are clearly inadequate.

There is considerable uncertainty about Grizzly bear population growth rates and unreported human kills, as well as how hunting affects other aspects of Grizzly bear biology such as genetics, social interactions and evolutionary processes.

It is also uncertain exactly how long different populations take to recover from population declines, the effects of changes to food availability and cumulative effects of other threats to grizzlies, logging and development for example.

Population uncertainties

Of great concern is the uncertainty of total population size. The current best estimate is 15,000 Grizzly bears in British Columbia – however the figure could be higher or lower.

It appears that few on-the-ground surveys have actually been done, with the estimate being largely based on computer modelling or expert opinion.

The government claims the management of the Grizzly bear hunt is based on “sound science” – yet Jessie Housty, tribal councillor of the Heiltsuk First Nation, doubts this.

On the Central BC Coast, where government sanctioned trophy hunting is at odds with tribal law that prohibits it, she emphasises that no inventories have been conducted.

“How could the government possibly have a solid understanding of these bears they condemn to the hunt without setting foot in our Territory?”

These are known unknowns

The government is failing to take all of these uncertainties into account when setting hunting limits, says Artelle.

“This uncertainty in and of itself is not inherently a problem – uncertainty exists in all management. The problem in BC Grizzly bear management is that the uncertainty is simply ignored.

“Although the government maintains their targets are conservative, a simple comparison between their own limits and their own records of kill rates show that is clearly not the case.”

Dr Chris Darimont, science director at the Raincoast Conservation Foundation (RCF) and a co-author of the study, is worried:

“Ignoring uncertainty – in dimensions such as true population size – is like playing Russian Roulette. As the history of wildlife management has shown repeatedly, the consequences of not accounting for the unknowns are grave.”

The RCF has raised concerns about BC’s Grizzly trophy hunt in the past. The European Union banned the import of BC Grizzly bear parts in 2002 due to their concerns over sustainability.

Hunting quotas should be halved – or banned

There is one very simple solution to the problem of overkills – reduce the hunt.

“If the government wants to ensure mortality levels are kept below limits set by their own biologists their targets need to be reduced,” says Artelle.

The scientists found that the BC government could reduce the risk to their Grizzly bears by cutting its hunting quotas by at least a half, which would reduce the probability of overkills by an average of 85%.

British Columbia is one of the last strongholds for North American Grizzly bears. Since European colonization, they have lost half of their continental range, and even in BC around one third of populations have either gone extinct or are currently threatened.

Multiple threats

“We know that grizzly bears are highly vulnerable to management error – because of their reproductive biology populations that suffer declines often don’t recover, or take considerable time to do so”, said Artelle.

“And at a provincial level the trend is not promising – through recent decades we have seen an overall trend of more and more populations gaining threatened status or disappearing altogether.

“We also know that grizzlies face a variety of other threats that are not yet fully understood, from declining salmon stocks on BC’s coast, white-bark pine failures inland, and climate change and development pressures throughout the province.

“Given the considerable threats many argue that grizzly managers should err on the side of caution, which our analyses strongly suggest they are not currently doing.”

Yet hunting increased

Despite these threats to the Grizzlies, during the study period, between 2001 and 2011, hunting mortality actually increased. For this reason, many people in BC are in favour of the complete elimination of trophy hunting in their province.

The Coastal First Nations, an alliance of nine BC First Nations, have called upon Premier Christy Clark to end the hunt by organizing a petition.

They have banned trophy hunting in their expansive traditional territories in BC’s Great Bear Rainforest because they believe that the government is risking the long-term survival of the bears.

Jessie Housty says: “Our responsibility as First Nations is to step into that regulatory vacuum, and protect the bears in our territories.”

80% of BC residents oppose the grizzly hunt

Environmentalists are also strongly opposed to the hunt, as are 80% of British Columbians, according to a recent McAllister Research Poll.

Throughout North America it is being recognised that hunting must be stopped in order to protect Grizzly bears. Yet in BC, despite widespread disapproval and bad science, the hunt looks set to continue. Artelle concludes:

“In other jurisdictions, such as the province of Alberta and the Kenai peninsula in Alaska, hunts have been closed due to sustainability concerns. In BC there has been a trend through time of a growing number of populations gaining threatened status.

“Whereas history from within and beyond the province suggests cautious management might be warranted, our research found that current management entails considerable risk, suggesting that continued overkills are likely.”

Anna Taylor is a freelance science journalist, specialising in environmental issues and new discoveries in conservation biology. She posts regular blogs on Conservation Jobs.

Anna has also worked in conservation and conservation research for RSPB and other employers in the UK, Africa and the Amazon. She has a BSc in Conservation Biology and a Masters in Ecology and Environmental Biology.

Source: http://www.theecologist.org/News/news_analysis/2271852/overkill_trophy_hunting_slams_bcs_grizzly_bears.html

BC grizzly bears are being over hunted, putting the future of the population at risk, say the authors of a new study released today in the scientific journal PLOS ONE.

Researchers from the University of Victoria, Simon Fraser University and Raincoast Conservation Foundation show in their report that there are serious shortfalls with the management of the grizzly bear hunt in BC.

Researchers found large discrepancies between the upper limit to kills set by the provincial government and the number of grizzly bears killed.

“In half of BC’s remaining grizzly populations, our audit detected overkills, and almost all were associated with excessive trophy hunting,” says Dr. Chris Darimont, UVic geography professor, Raincoast science director and the study’s co-author. “The pattern of overkills we documented surprised and alarmed us, especially for female grizzly bears, which are the reproductive powerhouses of populations.”

BC represents one of the last strongholds for grizzly bears, which have lost about half of their historical range in North America since European colonization.

The report, Confronting Uncertainty in Wildlife Management: Performance of Grizzly Bear Management, is co-authored by Kyle Artelle (lead) and Sean Anderson, SFU PhD students; SFU professors Dr. John Reynolds and Dr. Andrew Cooper, and Dr. Paul Paquet, Raincoast senior scientist and adjunct UVic geography professor.

The report is available at PLOS ONE http://dx.plos.org/10.1371/journal.pone.0078041

THE EXTERMINATION OF THE AMERICAN BISON.

The Project Gutenberg EBook of The Extermination of the American Bison, by William T. Hornaday

This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at http://www.gutenberg.org

Title: The Extermination of the American Bison

Author: William T. Hornaday

Bull Buffalo in National Museum Group. Drawn by Ernest E. Thompson.

Access to the E-Book: http://www.gutenberg.org/files/17748/17748-h/17748-h.htm or http://www.gutenberg.org/ebooks/17748

More information: http://siarchives.si.edu/oldsite/history/exhibits/documents/hornaday.htm

Fox Dives Headfirst Into Snow

A red fox pinpoints field mice buried deep beneath the snow, using his sensitive hearing and the magnetic field of the North Pole to plot his trajectory.

Cougar Predation Key To Ecosystem Health

A new study by researchers from Oregon State University found that cougars in Zion National Park have a profound impact on other aspects of the ecosystem, primarily by controlling deer populations and the ecosystem alterations related to deer browsing.

The general disappearance of cougars from a portion of Zion National Park in the past 70 years has allowed deer populations to dramatically increase, leading to severe ecological damage, loss of cottonwood trees, eroding streambanks and declining biodiversity. Researchers are calling it a “trophic cascade” of environmental degradation.

This “trophic cascade” of environmental degradation, all linked to the decline of a major predator, has been shown in a new study to affect a broad range of terrestrial and aquatic species, according to scientists from Oregon State University.

The research was just published in the journal Biological Conservation — and, like recent studies outlining similar ecological ripple effects following the disappearance of wolves in the American West — may cause land managers to reconsider the importance of predatory species in how ecosystems function.

The findings are consistent, researchers say, with predictions made more than half a century ago by the famed naturalist Aldo Leopold, often considered the father of wildlife ecology.

“When park development caused cougar to begin leaving Zion Canyon in the 1930s, it allowed much higher levels of deer browsing,” said Robert Beschta, an OSU professor emeritus of forest hydrology. “That set in motion a long cascade of changes that resulted in the loss of most cottonwoods along the streambanks and heavy bank erosion.”

“But the end result isn’t just loss of trees,” he said. “It’s the decline or disappearance of shrubs, wetland plants, amphibians, lizards, wildflowers, and even butterflies.”

Until recently, ecologists had a poor understanding of how the loss of an important predator, such as wolves or cougar, could affect such a broad range of other plant and animal species. But the evidence is now accumulating that primary predators not only have direct effects in influencing the population sizes of native grazing animals such as deer and elk — they also have indirect effects in changing their foraging behavior, in what has been called “the ecology of fear.”

That phenomenon, the scientists say, has been shown as vividly in Zion National Park as any other location they have ever studied.

In Zion Canyon, which since the early 1900s has been a popular tourist attraction, cougars are virtually absent, mostly just scared off by the huge influx of human visitors. With their natural enemy gone, growing and ravenous deer populations ate young cottonwood trees almost as quickly as they sprouted, robbing streambanks of shade and erosion protection.

As a result, floodplains began to erode away. Other types of vegetation and the animal species dependent on them suffered. And unless something is done, cottonwoods in Zion Canyon may ultimately disappear in areas accessible to deer, the researchers said.

By contrast, a nearby roadless watershed has similar native ecology but is sufficiently remote that it still has an intact cougar population and far fewer mule deer. In contrast to Zion Canyon, streambanks in this watershed have nearly 50 times more young cottonwood trees as well as thriving populations of flowers, lizards, butterflies, and several species of water-loving plants that help stabilize stream banks, provide food-web support, and protect floodplains for use by many other animal species.

“The documentation of species abundance that we have in this study is very compelling,” said William Ripple, a professor in the OSU Department of Forest Resources and lead author on the study. Researchers did a systematic survey of channel dimensions, streambank condition, vegetation and species presence along each study site.

“These two canyons, almost side by side, have a similar climate and their ecosystems should be quite similar,” Ripple said. “But instead they are very different, and we hypothesize that the long-term lack of cottonwood recruitment associated with stream-side areas in Zion Canyon indicates the effects of low cougar and high deer densities over many decades.

“It’s a great research setting and a great opportunity to assess the potential importance of a key predator,” he said. “We hope to conduct additional research in Zion National Park to further explore the findings of this initial study.”

It’s important to remember, the researchers said, that the ultimate driver behind all of these changes is humans — in the case of Zion Canyon, simply by their presence. That canyon receives nearly three million human visitors a year, the adjacent North Creek a stray handful of hikers. Cougars in Zion Canyon were not intentionally killed or removed, they just left due to the increased presence of humans.

As findings such as this — the way cougars affect deer and wolves affect elk — continue to mount, land managers may have to acknowledge the potentially enormous impact of these grazing animals on other ecosystem processes, scientists say. This could open the way to new management options once the role of herbivory by deer, elk, or other grazing animals is more fully understood.

In systems with wild ungulates, the sustainability of riparian habitats and biodiversity may require both predation on these herbivores as well as the fear of predation to further affect their behavior, the researchers concluded.

Ripple and Beschta considered other factors that may have played a role in loss of cottonwood trees in Zion Canyon, such as climate fluctuations or human interventions to stream channels, but concluded that those impacts could not have caused the enormous loss of trees and associated impacts to other biota that were found in the canyon.

The findings of this study may be relevant to other ecosystems in the U.S. and around the world where key predators have been removed, the researchers said, and high populations of native herbivores such as deer or elk — or domestic grazers such as cattle or sheep — affect native biodiversity.

This research was funded by the National Park Service.

 Story Source: The above story is based on materials provided by Oregon State University. Note: Materials may be edited for content and length.

Source: http://www.sciencedaily.com/releases/2006/10/061024214739.htm

Over 75 percent of large predators are declining

The world’s top carnivores are in big trouble: this is the take-away message from a new review paper published today in Science. Looking at 31 large-bodied carnivore species (i.e those over 15 kilograms or 33 pounds), the researchers found that 77 percent are in decline and more than half have seen their historical ranges decline by over 50 percent. In fact, the major study comes just days after new research found that the genetically-unique West African lion is down to just 250 breeding adults.

“Globally, we are losing our large carnivores,” says lead author of the study, William Ripple, with Oregon State University. “Many of them are endangered. Their ranges are collapsing. Many of these animals are at risk of extinction, either locally or globally. And, ironically, they are vanishing just as we are learning about their important ecological effects.”

The story of the world’s large carnivores is a largely bleak one. In the not so distant past, most people—even scientists—largely viewed large carnivores as competitors, pests, and deadly threats. Such views led to conflict and even extermination campaigns that killed-off many of the world’s top predators in Europe, North America, the Middle East, and North Africa, and decimated populations elsewhere. In fact, the study finds that 66 percent of the 31 biggest carnivores are currently listed as threatened on the IUCN Red List.

The leopard has lost 35 percent of its historical range and is decreasing. Photo by: Kirstin Abley.

“These carnivores often require large prey and expansive habitats,” write the scientists. “It is these food requirements and wide-ranging behavior that often bring them into conflict with humans and livestock. This, in addition to human intolerance, renders them vulnerable to extinction.”

In many parts of the world, top predators are still shot, trapped, poisoned, or even speared. Even where they are not directly targeted, big predators are rapidly losing both their habitat and their prey base, leading to a trend of vanishing top predators even in protected areas.

According to the study, the major trend underpinning this global decline in big predators is the rapidly-rising population of another predator: humans.

“An increasing human population and subsequent rate of urbanization inevitably means many habitats will be further reduced or modified. This will place top predators at increased risk of extinction,” co-author Euan Ritchie with Deakin University in Australia told mongabay.com., adding that “the issue of an increasing human population poses challenges well beyond just maintaining top predators in the environment. How we are going to produce enough food while still maintaining the biodiversity we are so dependent upon is arguably society’s greatest challenge.”

However, even as most big-bodied predators continue to decline, popular views of these megafauna are slowly shifting. Large-bodied predators now have many conservation champions, and elucidate passionate responses from advocates. These animals are also often seen as key symbols for global conservation efforts, and in some parts of the world (notably the U.S. and Europe) a few big predators are staging mini-comebacks. But perhaps, more importantly, scientists are just beginning to understand the outsized role of big carnivores in the world’s ecosystems.

Sea otters play a major role in the health of kelp forests. Photo by: Norman S. Smith.

“There is now overwhelming evidence from around the world that we are better off with top predators in the environment because of the many important roles they perform, such as reducing overgrazing of vegetation by herbivores which increases the carbon sequestration capabilities of habitats and in turn assists with ameliorating the impacts of climate change,” says Ritchie.

In fact, scientists have long theorized that big predators exert a powerful ecological influence on the foodchain by keeping herbivore populations low, but now they are discovering additional avenues in which big carnivores impact ecosystems. For one thing, top predators also keep mesopredators (medium-sized predators) in check via harassment, intimidation, and sometimes downright killing. Losing big predators can mean a sudden explosion of mesopredator abundance, impacting species all down the line. For example, Australia has built a massive fence that keeps the dingoes (Canis lupus dingo) out of sheep grazing areas. However, in these same areas, red fox—an invasive predator—runs amuck, leading to increased pressure on native mammals.

“Overall, the suppression of dingoes has probably contributed to the endangerment and extinction of small marsupials and rodents over much of the continent,” the scientists write.

The unmistakable importance of predators is not regulated to the land alone. Research has shown that sea otters (Enhydra lutris) exert a huge influence on their environment by keeping urchin populations in control. When sea otters are killed off, sea urchin populations explode, decimating kelp forests. The researchers write that sea otters “[enhance] the abundance and distribution of kelp and other fleshy macroalgae in coastal inshore ecosystems.”

Gray wolf in Yellowstone National Park: the top predators were reintroduced into the park after a 70 year absence. Photo by: Doug McLaughlin.

Probably the most famous example of the importance of top predators comes from Yellowstone National Park. The reintroduction of wolves into the park in the 1990s has had massive impacts on the ecosystem. With the return of the wolves, elk behavior changed significantly: instead of browsing out in the open, they took to the forests for protection. This allowed trees to grow unimpeded in many parts of the park where they had been overgrazed for decades, including along river and stream beds. The impacts spread to songbirds, beavers, fish, overall biodiversity and even carbon sequestration. In a roundabout way, wolves became the true aborists of Yellowstone.

The American black bear is the world’s only bear species whose population is on the rise. Photo by: Public Domain.

The American black bear is the world’s only bear species whose population is on the rise. Photo by: Public Domain. “I am impressed with how resilient the Yellowstone ecosystem is. It isn’t happening quickly everywhere, but in some places, ecosystem restoration has started there,” says Ripple. “Nature is highly interconnected. The work at Yellowstone and other places shows how one species affects another and another through different pathways. It’s humbling as a scientist to see the interconnectedness of nature.”

Given this changing understanding of predator importance, Ritchie says many of the world’s governments are woefully mismanaging their predator populations.

Gray wolf in Yellowstone National Park: the top predators were reintroduced into the park after a 70 year absence. Photo by: Doug McLaughlin.

“In the case of wolves in North America and dingoes in Australia, their lethal control often fractures social structures leading to more not less wolves and dingoes and often increased not decreased attacks on livestock,” says Ritchie, who argues that policies of culling predators “potentially [exacerbate]” human conflict with predators” and undercut ecosystem services.

“Governments should instead promote policies and actions such as using guardian animals for protecting livestock, as this will lead to improved and sustained environmental and economic outcomes,” he adds.

But how many predators are needed to fulfill their ecological role? In many cases, scientists aren’t wholly certain, but Ritchie says the answer is actually more complex than a simple number.

“It’s not just how many predators there are but the age and sex of individuals is important. When predator populations are greatly reduced and interfered with through lethal control, relationships between individuals breakdown and predators can behave in unexpected and sometimes very negative ways,” he notes. In many predatory species, infants and adolescents learn from older individuals. When mature individuals are killed-off, young predators are left without their mentors, often leading to more erratic behavior and posing a higher risk both to livestock and people.

Despite growing knowledge about the importance of top predators, the ecological role of most of the world’s large-bodied predators remains unknown. Perhaps more alarming still, scientists lack good data on the population sizes of many of the world’s top predators, leaving conservationists guessing. But where information is available: it is disheartening. Lion populations have fallen from an estimated 100,000 in 1960 to 15,000-35,000 today. There are currently more captive tigers in the U.S. alone than there are tigers in the wild worldwide (about 3,200). The Ethiopian wolf (Canis simensis) has lost 98 percent of its historical range and sports a total population of less than 500.

Not all the news is bleak: wolves are returning to long-lost habitats in the U.S. and Western Europe, conservationists have launched a massive campaign to double tiger numbers in the wild by 2022, and the world’s rarest big predator—the red wolf (Canis rufus)—is bouncing back after once being thought totally extinct. However, the bad news—and the relentless pressures—very much outweighs the good for the world’s big predators.

“Promoting tolerance and coexistence with large carnivores is a crucial societal challenge that will ultimately determine the fate of Earth’s largest carnivores and all that depends upon them, including humans,” the scientists conclude.

The dingo fence is one of the longest structure on the planet, stretching for 5,614 kilometers (3,488 miles).

Wolves killed in Russia. In much of the world, governments still practice massive culling measures to manage carnivores.

The Javan tiger, a distinct subspecies, went extinct in the 1970s. Photo by: Public Domain.

Citations:

• W.J. Ripple, R.L. Beschta, M.P. Nelson, et al. Status and Ecological Effects of the World’s Largest Carnivores. Science (2014) Vol 334.

This article was written by Jeremy Hance for Mongabay.com

Source: http://focusingonwildlife.com/news/over-75-percent-of-large-predators-declining/