Italian wolves prefer pork to venison

Some European wolves have a distinct preference for wild boar over other prey, according to new research.

Scientists from Durham University, UK, in collaboration with the University of Sassari in Italy, found that the diet of wolves was consistently dominated by the consumption of wild boar which accounted for about two thirds of total prey biomass, with roe deer accounting for around a third.

The study analysed the remains of prey items in almost 2000 samples of wolf dung over a nine year period and revealed that an increase in roe deer in the wolf diet only occurred in years when boar densities were very low. In years of high roe deer densities, the wolves still preferred to catch wild boar.

The results are published in the journal PLOS ONE.

The research team related the prey remains in wolf dung to the availability of possible prey in part of Tuscany, Italy - an area recently colonised by wolves. The findings have implications for wildlife conservation as the impact of changing predator numbers on prey species is important for managing populations of both predators and prey.

Lead author, Miranda Davis, from the School of Biological and Biomedical Sciences at Durham University, said: "Our research demonstrates a consistent selection for wild boar among wolves in the study area, which could affect other prey species such as roe deer."

"Intriguingly, in other parts of Europe where red deer are also available, wolves appear to prefer this prey to wild boar, suggesting that they discriminate between different types of venison."

In Europe, the wolf (Canis lupis) is recovering from centuries of persecution and the expansion of wolf populations has the potential to change the ecology of communities of ungulates (hooved animals) by exposing them to natural predation by wolves, according to the researchers.

The preference for boar is in contrast to other areas of Europe where wolves often avoid boar as prey. One factor may be the relatively smaller size of Mediterranean boar, making them less dangerous to wolves in Mediterranean regions, compared to the larger-sized boar that roam other parts of Europe.

Co-author, Dr Stephen Willis, from the School of Biological and Biomedical Sciences at Durham University, said: "Wolves were hunted to extinction in the UK, probably by the end of the 17th century. Our findings from Italy suggest that if they were reintroduced into an area with a healthy ungulate population their impact on livestock could be minimal."

Tuscany's woodlands support populations of both roe deer and wild boar, and are also grazed by sheep, goats and cattle; however, wild boar and roe deer made up over 95 per cent of wolf diet in the study area, with very little evidence of livestock predation.

The scientists identified prey items from fragments of bones and hair in the wolf dung collected in the region. The prey categories included wild boar, roe deer, red deer, hare, small rodents, goats, sheep and cattle.

For more than five years of the study, the percentage of wolf diet made up of wild boar was more than twice that of roe deer. Other prey represented only a very small proportion of the diet.

The researchers believe that further dietary studies are essential for understanding the true impact of wolves on European wildlife over time.

Co-author, Dr Phil Stephens, from the School of Biological and Biomedical Sciences at Durham University added: "Wolves and brown bears are gradually returning to their former strongholds in Europe. Understanding the needs of these species, as well as their potential impacts, is going to be fundamental to managing that welcome return."

Elk bones tell stories of life, death, and habitat use at Yellowstone National Park

Josh Miller likes to call himself a conservation paleobiologist. The label makes sense when he explains how he uses bones as up-to-last-season information on contemporary animal populations.

Bones, he says, provide baseline ecological data on animals complementary to aerial counts, adding a historical component to live observation. In his November cover article for the Ecological Society of America's journal Ecology, he assesses elk habitat use in Yellowstone National Park by their bones and antlers, testing his method against several decades of the Park Service's meticulous observations.

Now an assistant research professor in the new Quaternary and Anthropocene Research Group in the Department of Geology at the University of Cincinnati, Miller located and recorded the elk bone data while a doctoral student in paleontology at the University of Chicago, and finished analyzing the data during a brief stint at the Florida Museum of Natural History at the University of Florida, in Gainesville. His work with modern animals grew out of curiosity about the fidelity of the fossil record in archiving animals and ecosystems of the distant past.

"It turns out that bones are really informative," he said. At Yellowstone, bone and antler concentrations mirror patterns of animal landscape use known from years of aerial surveys. "This opened up a completely unexpected opportunity for studying modern ecosystems, particularly for areas where our knowledge of animal populations is more limited."

Reconstructing animal community structure and habitat use through the bones of past generations is a new idea. Until recently, common knowledge held that, on the landscape, bones just don't last that long. But Miller has found that they can last for hundreds of years. Bones weather in a stereotypical pattern, from fresh to falling apart. He calibrated weathering in the Yellowstone bones through radiocarbon dating, gaining a familiarity that would allow him to pick up a bone and know it had seen a year, 20 years, or 80 to 100 years or more on the open ground.

Bull elk shed their antlers in late winter, when forage is sparse. Too poor in nutrients to interest most scavengers, heavy, and awkwardly shaped for displacement by the elements, antlers tend to stay where they fall. Miller found that, for the most part, the bones of calves don't travel far either, even in the mouths of predators. The bones of calves mark the range where their mothers sought plentiful food to fuel months of nursing, and shelter to hide their vulnerable newborns.

Old bones from past decades outline a range consistent with the living herd. Miller saw only moderate shifts in a few areas, even given the many recent changes at Yellowstone: the prodigious wildfires of 1988, repatriation of grey wolves starting in 1995, and regrowth of willows, aspen, and cottonwoods over the last couple of decades following a long decline during the 20th century.

Because bones can last decades to centuries in the Yellowstone environment, Miller says they can put relatively recent data from direct observation into broader context for managers looking at long-range planning, helping to sort out important changes from the noise of cyclical booms, busts and shifts in landscape use. Bones are a minimally invasive tool for tracking the history of range animals. They are data just lying on the ground, waiting to be collected.

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Spatial fidelity of skeletal remains: elk wintering and calving grounds revealed by bones on the Yellowstone landscape (2012) Joshua H. Miller. Ecology 93:11, 2474-2482.

Yellowstone wolf study reveals how to raise successful offspring

What are the key ingredients to raising successful, self-sufficient offspring? A new life sciences study using 14 years of data on gray wolves in Yellowstone National Park indicates that cooperative group behavior and a mother's weight are crucial. "A female's body weight is key in the survival of her offspring, and cooperation in the protection and feeding of young pups pays off in terms of the production of offspring," said Robert Wayne, a professor of ecology and evolutionary biology at UCLA and co-author of the new research, published this week in the online edition of the Journal of Animal Ecology. Wolves are social carnivores that live in territorial, kin-structured packs. Female wolves depend on other adults in the pack to help them provide food for their pups and defend the youngsters from predators — mainly, competing packs of wolves. The greater the group cooperation, the researchers say, the better the pack's survival advantage. "Consequently, larger packs tend to get larger and win the 'arms race' of holding territories against the aggressive actions of other packs," Wayne said. "Large packs get better at building armies of soldiers to defend their turf, and cooperative behavior and sociality are maintained by natural selection." Wolves were re-introduced into Yellowstone Park in the mid-1990s and are rapidly becoming one of the best-studied carnivore populations in the world; they are turning out to be an excellent model for the study of sociality and cooperation, Wayne said. Over many years of intensive collaborative study, former UCLA graduate student Dan Stahler (now a biologist with the National Park Service) and former UCLA postdoctoral scholar Bridgett vonHoldt (who worked in Wayne's laboratory and will soon become an assistant professor at Princeton University) analyzed genetic and life-history data on more than 300 gray wolves. They assessed survivorship and reproductive success, as well as the factors that influenced them, including body weight and pack size, among other variables. They found a striking association between pack size, body weight and offspring survival. "We discovered that mother wolves' body weight and pack size play a crucial role in enabling pups to survive and thrive from birth to young adulthood," said Utah State University assistant professor of wildlife resources Dan MacNulty, a co-author of the study. The research was funded by the National Science Foundation, the National Park Service and the Yellowstone Park Foundation, as well as private donors. Environmental conditions that impact wolf reproduction, the researchers say, include resource availability, population density and disease prevalence — especially deadly canine distemper, caused by a contagious virus to which pups are especially vulnerable. In addition to body weight and pack size, the researchers examined the effects of maternal age and color (gray or black coat) and wolf population size on reproductive success. "Each of these factors affects reproduction, but, overwhelmingly, female body weight and pack size are the main drivers of litter size and pup survival," said Stahler, the study's lead author. "Bigger females produce bigger litters; bigger packs are better equipped to hunt and defend pups and resources from competitors."

Group Dynamics of Yellowstone Pronghorn

The American pronghorn in the Yellowstone region have proven to be gregarious animals. Observations of group dynamics have found their interactions to be influenced by social, reproductive, and environmental factors. Pronghorn were also found to be somewhat unpredictable, making it more challenging to develop conservation strategies for this species. A study published in the Journal of Mammalogy reported about tracking the locations of 53 adult female pronghorn fitted with VHF and GPS radio collars in Yellowstone National Park for nearly 6 years. The Yellowstone population of pronghorn is a native species of special concern. They number fewer than 300, and are one of only a few pronghorn migrations remaining in the greater Yellowstone region. Observing changes in how animals behave as groups can give clues to the influence of environmental and human factors on their survival. The American pronghorn displays flexibility in behaviors of grouping and mating that could indicate resilience to changes in the environment, but this flexibility can make it difficult to create management strategies for the population. Grouping patterns of pronghorn change due to availability of food, density and demographic variables within the group, and human factors such as fencing and hunting. In this study, females switched groups frequently, and groups became smaller when females were giving birth and rearing their young. Snow pack and the number of predators also affected group sizes and cohesion, but habitat and vegetation had less influence. Examination of Yellowstone pronghorn found that they favor lower elevations during the winter, avoiding deep snow. Building on this information, the National Park Service has undertaken restoration efforts to ensure that native vegetation and migration routes to these favored areas are re-established. Conservation efforts seek to control disease, protect or restore key habitat, regulate harvests, and limit adverse effects of development and recreation. When planning the timing and location for conservation actions, biologists must consider what this grouping behavior can reveal about the species. Full text of “Group Dynamics of Yellowstone Pronghorn,” Journal of Mammalogy, Vol. 93, No. 4, 2012, is available at http://asmjournals.org/.

Wolf mange part of nature's cycle

Mange and viral diseases have a substantial, recurring impact on the health and size of reintroduced wolf packs living in Yellowstone National Park, according to ecologists.

Following the restoration of gray wolves to Yellowstone in 1996, researchers collected blood from the animals to monitor parasite-induced disease and death. They also tracked the wolves in each pack to follow their survival and allow additional data-gathering.

"Many invasive species flourish because they lack their native predators and pathogens, but in Yellowstone we restored a native predator to an ecosystem that had other canids present that were capable of sustaining a lot of infections in their absence," said Emily S. Almberg, graduate student in ecology, Penn State. "It's not terribly surprising that we were able to witness and confirm that there was a relatively short window in which the reintroduced wolves stayed disease-free."

The researchers found that within a year after the wolves were reintroduced to Yellowstone, 100 percent of the wolves tested had at least one infection, but mange did not infect wolves living in the park until 2007.

"We can look at the biology of the diseases and predict which ones will come in first," said Peter J. Hudson, Willaman Professor of Biology and director of the Huck Institutes of the Life Sciences, Penn State. "What was surprising was that so many diseases came in so fast, but those were the ones we expected to come in first. It wasn't really a sequence, they were almost there immediately. That's very interesting in itself. "

The diseases that infected the wolves quickly were all viral, including canine distemper and canine parvovirus -- both contractible through bodily secretions. Mange, however, is a skin infection, caused by scabies mites, that makes the wolves scratch and lose fur. An infected wolf can lose enough body heat in the winter to freeze to death. Mange is spread by direct contact with another mite-infected animal or by contact with the mites themselves, as they can survive away from a host for several days, depending on the temperature.

"Where did those diseases come from?" asked Hudson. "Most of them initially came from other canid species, like coyotes or foxes. Wolves are animals that disperse far and move around fast, and once the wolves were established the diseases were spread from pack to pack."

Almberg and Hudson tracked how quickly mange spread from pack to pack after the disease entered the population. The number of infected wolves in a pack did not affect the likelihood of a neighboring pack to contract mange, but distance was a factor -- for every six miles of distance between an infected pack and an uninfected pack, there was a 66 percent drop in risk for the uninfected pack. Some wolves and packs were not severely affected by mange, while other packs were decimated, the researchers report in the current issue of Philosophical Transactions of the Royal Society B.

In January 2007, Mollie's pack was the first in Yellowstone to show signs of mange infection. As of March 2011, they had recovered. The Druid pack, which had been one of the most stable and visible packs in the park, according to Almberg, started to show signs of mange in August 2009.

"It was in a very short amount of time that the majority of the animals [in Druid] became severely infected," Almberg said. "The majority of their hair was missing from their bodies and it hit them right in the middle of winter. The summer before it got really bad, we saw that many of the pups had mange."

The Druid pack was gone by the end of the winter in 2010.

The researchers note that the wolf population in Yellowstone experienced several phases -- from 1995 to 2003 the wolves experienced rapid growth, from 2003 to 2007 the number of wolves stabilized, and the most recent data from 2007 to 2010 shows a decline.

"We're down to extremely low levels of wolves right now, we're down to [similar numbers as] the early years of reintroduction," said Almberg. "So it doesn't look like it's going to be as large and as a stable a population as was maybe initially thought."

Do beavers benefit Scottish wild salmon?

Reintroduced European beavers could have an overall positive impact on wild salmon populations in Scotland, according to a study by the University of Southampton.

Representatives of recreational fisheries interests north and south of the border are concerned that beavers can harm economically important fish stocks due to their dam building activities and potential to block migratory life phases. However, results of a study conducted by scientists at the University of Southampton, funded by Scottish Natural Heritage, indicate that beavers can also have substantial beneficial effects which may outweigh those that are negative.

The study's findings highlight that while the activities of beavers can result in localised and often temporary negative impacts on fish, primarily due to dams impeding their movements and reducing the availability of suitable spawning habitat, these can be at least off-set by the benefits of increased habitat diversity and resulting abundance and productivity of fish, including salmon.

Dr Paul Kemp, a researcher in freshwater fish ecology and fisheries management from the University's International Centre for Ecohydraulics Research, who lesd the study comments that, "the positive findings were more frequently based on quantitative evidence, while discussion of negative impacts was often speculative."

Dr Kemp and his colleagues were surprised that the "weight of evidence" tended to indicate an overall positive effect considering the background of those who participated in the survey. "Most participants were from a fisheries background and whom you might expect would tend to side with the fish, but based on their experience of beaver and fish interactions tended to be positive towards beaver," he says.

Beaver reintroduction has been a contentious issue in Scotland ever since a total of 16 individuals from Norway were released in Argyll in 2009 and 2010 as part of a scientific trial conducted by the Scottish Wildlife Trust, The Royal Zoological Society of Scotland, and the host partners, the Forestry Commission Scotland.

Even more controversy surrounds the establishment of a breeding population of escaped beavers on the River Tay. This has had ramifications south of the border as the Angling Trust has written to Richard Benyon, the UK minister for Fisheries and the Natural Environment, requesting that trapping and destruction of the beavers be urgently undertaken to prevent their spread to England where it is claimed they could damage fisheries.

Researchers carried out a critical view of over 100 sources of peer-reviewed information in which benefits were cited 184 times compared to 119 for the negative effects. Analysis of existing literature indicates that beaver activity can have both positive and negative effects on fish. Negative effects relate to the construction of beaver dams which can temporarily impede the movement of some fish, particularly in narrow rivers and streams, while siltation can cause loss of spawning habitat immediately upstream of dams. But beavers can also have beneficial effects on fish by increasing the variety and area of habitats in streams, and due to the presence of dams and ponds by increasing the abundance of invertebrates, which form the main component of the diet of many stream-dwelling fish, and providing refuge during periods of high or low water flows.

The study, which was published in the leading international fisheries journal Fish and Fisheries, also reports the findings of an expert opinion survey of 49 fisheries managers, scientists, and beaver ecology experts, from Europe and North America, where most of the research has been conducted. More than half (58 per cent) of those who responded believed that the overall impact of beavers on fish populations was positive.

Professor Roger Wheater, the Chair of the Beaver-Salmonid Working Group, says: "I would be very surprised if biodiversity were not increased but our concern continues to be the impact on salmonid spawning areas and the management required to deal with situations where salmonids in any particular system are at risk."

Bears, scavengers count on all-you-can-eat salmon buffet lasting for months

Salmon conservation shouldn't narrowly focus on managing flows in streams and rivers or on preserving only places that currently have strong salmon runs.

Instead, watersheds need a good mix of steep, cold-running streams and slower, meandering streams of warmer water to keep options open for salmon adapted to reproduce better in one setting than the other, new research shows. Preserving that sort of varied landscape serves not just salmon, it provides an all-summer buffet that brown bears, gulls and other animals need to sustain themselves the rest of the year.

"In any one stream, salmon might spawn for two to four weeks," said Peter Lisi, a University of Washington doctoral student in aquatic and fishery sciences, who studies the Wood River watershed in southwest Alaska.

"Animals like coastal brown bears and Glaucus-winged gulls gorge themselves at one stream for a few weeks and then just move to another stream that might have water temperatures a few degrees warmer and therefore support salmon populations that spawn at a later time," he said. "It's easy for animals to move when such streams are as little as a mile or two apart."

"A whole network of streams, some colder and some warmer, provides what Lisi and Daniel Schindler, UW professor of aquatic and fishery sciences, call "hydrological diversity." Such diversity more than triples the time predators have access to salmon in a summer, from just a few weeks to more than three months in the watershed studied.

The researchers' paper on landscape attributes that influence spawn times will be presented Aug. 8 in Portland, Ore., during the Ecological Society of America's annual meeting.

"Both Glaucus-winged gulls and brown bears have very short growing seasons at high latitudes. Salmon are a key resource that allows these species to fatten up and achieve the necessary annual growth in this short period of time," Schindler said. "A complex landscape results in streams of differing temperature so salmon populations don't spawn at the same time. Predators and scavengers have a much longer window of accessibility."

"We knew that salmon are an important seasonal resource for lots of predators and consumers. However, there is little appreciation for the importance of biological diversity within salmon for these consumers."

The response of salmon to hydrologic diversity is what makes stocks viable over time and will probably make them better able to respond to climate change, Lisi said. Instead of focusing narrowly on flow regimes or trying to decide which individual streams and rivers to protect, a better goal would be to protect a wide range of hydrologic conditions, the co-authors said.

""Biological diversity within salmon stocks has important benefits to terrestrial ecosystems," Schindler said. "This scale of variation in hydrology, geomorphology and biological diversity is often swept under the rug and dismissed as unimportant in activities such as river restoration, projections of climate impacts and fishery management."

The paper, part of a session on linkages between aquatic and terrestrial systems, also describes how biological diversity in returning salmon are linked to the pollination of a flowering plant, something no other group has described.

Populations of kneeling angelica, 3-to-6-foot plants loaded with clusters of tiny white blossoms, don't all bloom at the same time, even though sun and weather conditions might be uniform across a watershed. Instead, these streamside plants have evolved to bloom approximately 10 days after salmon typically arrive at a particular stream.

It takes about that long for salmon to start to die, many of which are killed by bears or die naturally after spawning. Blowflies lay eggs on the carcasses and the result is a population boom of maggots to take advantage of all the dead salmon. Those maggots emerge as adult blowflies the next summer just in time for the salmon run. Before laying their eggs, the blowflies swarm kneeling angelica flowers to feed on nectar, spreading pollen at the same time.

Previous research has looked at direct connections to plants, such as roots taking up nutrients when salmon carcasses decay, Lisi said. This is an indirect consumer pathway.

"Kneeling angelica are among the last plants to bloom. It's fall, everything else is dying, most of the insects are gone but these plants hold out for the arrival of salmon," Lisi said.

Study: Wolverines need refrigerators

Will insects and bacteria consume more of the wolverine's food if the climate warms?

Wolverines live in harsh conditions; they range over large areas of cold mountainous low-productivity habitat with persistent snow. The paper suggests wolverines take advantage of the crevices and boulders of the mountainous terrain, as well as the snow cover to cache and "refrigerate" food sources such as elk, caribou, moose and mountain goat carrion, ground squirrels and other food collected during more plentiful times of year. These cold, structured chambers provide protection of the food supply from scavengers, insects and bacteria. In addition, the refrigerated caches increase the predictability of available food resources, reduce the energy spent by females searching for food while in lactation phase, and decrease the time mothers spend away from cubs.

The paper appears in the current edition of the Journal of Mammalogy and was co-authored by Robert M. Inman of WCS, Audrey J. Magoun of Wildlife Research and Management, Jens Persson of the Swedish University of Agricultural Sciences, and Jenny Mattisson of the Norwegian Institute for Nature Research.

"People don't normally think of insects and microbes as being in competition for food with wolverines," said lead author Robert Inman of the Wildlife Conservation Society's North America Program. "But in fact, bacteria will devour an unprotected food source if that source is available."

Through an extensive literary review, the authors noted that wolverine reproduction is confined to a brief period of the year, and the lactation phase in females (February through April) corresponds to a period of low availability of food resources. Wolverines, which are opportunistic foragers, have adapted by amassing food caches during the preceding winter months when food is more readily available. Without the cached food supply or an unforeseen alternative (such as a winter-killed ungulate), early litter loss occurs.

Inman said, "Understanding why and how wolverines exist where they do and the various adaptations they have evolved to eke out a living will better inform population management strategies and conservation of the species."

Climate change will play a key role in management planning for the conservation of wolverines, the authors say.

In a study published in 2010, wolverine biologists demonstrated a relationship between the areas where wolverines exist (their distribution) and persistent snow cover. The first theory advanced was that wolverines must have deep snow available in springtime so that they can give birth to their small cubs in a warm, secure den. The newly released study suggests that other factors related to climate and snow pack, such as competition for food, may also be involved in explaining the limits to wolverine distribution.

Because of their dependence on snow pack, wolverines were recently listed as warranted for protection under the Endangered Species Act due in large part to the threat of climate change reducing distribution and habitat connectivity. The authors say that a deeper understanding of how and why wolverines use snow pack the ways they do is critical to understanding how climate change will impact survival and reproductive rates.

"Shedding light on the specific mechanism of how climate will affect wolverines is important in order to know what to do to help them hold on," said WCS's North America Program Director, Jodi Hilty.

Inman and co-authors published a study in December of 2011 on the spatial ecology of wolverines in the Journal of Wildlife Management. This latest paper represents the second of several that will help to inform a conservation strategy for the species.

The Iberian wolf lives close to humans more for refuge than for prey

The Iberian wolf lives in increasingly humanised landscapes, with limited food resources and its presence is not always welcome. But, according to Spanish researchers, food availability plays a secondary role compared to landscape characteristics, which can offer refuge and allow wolves to remain in human-dominated environments in Galicia.

The habitat of the Iberian wolf (Canis lupus signatus) varies greatly across the Iberian Peninsula and its diet revolves around what is available, ranging from wild animals to domestic waste. In contrast, this predator is able to survive in humanised landscapes where characteristics provide them refuge from humans.

"Although the wolf boasts highly adaptable strategies for survival, landscape is the factor we have analysed that best explains their distribution across Galicia," as explained to SINC by Luis Llaneza, researcher at Asesores en Recursos Naturales (A.RE.NA.) and lead author of the study published in the 'Diversity and Distributions' journal.

His research has allowed for the analysis of the relative influence of landscape attributes, human presence and food resources and the existence of wolves over an area of 30.000 km2 in the north-west of the Peninsula.

The scientists concentrated on indirect signs of the animal to identify their distribution in Galicia. In total, 1,594 excrement samples were analysed, which were then verified using DNA molecular analysis to locate them in the territory.

The results revealed that landscape properties are decisive in terms of animal safety at a level of 48%, whereas the presence of humans (buildings and roads) is influential at a level of 35% and food availability as 17%. Llaneza says that "as long as tolerated by humans, the wolf can be found in any place where there is refuge and food."

According to the scientists' model, the presence of wolves would increase if there were more semi-wild horses and wild ungulates. As the authors outline, "the amount of semi-wild horses in Galicia could be a key factor determining the presence of wolves in areas where wild prey or other food sources area not so abundant."

A safe refuge for the wolf

After studying the effect of altitude, land orography and refuge availability, researchers demonstrated that these mammals require their habitat to be a plant mosaic containing vegetation of more than 50 centimetres in height (bushes and shrubs) to hide in.

"These animals remain in Spain and little by little we are beginning to understand how they survive in human-dominated areas," says Llaneza. The study reveals that wolves choose high places that are difficult to access, such as areas where vegetation provides refuge from humans.

"The density of vegetation allows wolves to go unnoticed by humans", adds the researcher, who recalls that humans are the known cause of wolf death in 91% of instances. Some 65% of wolves are killed on the road, 20% by poaching and 6% by legal hunting.

With the participation of the University of Santiago de Compostela and the Doñana Biological Station (EBD-CSIC), the research team concludes that a set of variables and data analysed explains only 20% of wolf distribution in Galicia. Their next undertaking will be the study of other factors that influence wolf survival in humanised areas, such as the extent to which they are tolerated.

Cougars are re-populating their historical range

American mountain lions, or cougars, are re-emerging 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 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 Km_ 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."

Loss of Predators in Northern Hemisphere Affecting Ecosystem Health

A survey on the loss in the Northern Hemisphere of large predators, particularly wolves, concludes that current populations of moose, deer, and other large herbivores far exceed their historic levels and are contributing to disrupted ecosystems.

The research, published recently by scientists from Oregon State University, examined 42 studies done over the past 50 years.

It found that the loss of major predators in forest ecosystems has allowed game animal populations to greatly increase, crippling the growth of young trees and reducing biodiversity. This also contributes to deforestation and results in less carbon sequestration, a potential concern with climate change.

"These issues do not just affect the United States and a few national parks," said William Ripple, an OSU professor of forestry and lead author of the study. "The data from Canada, Alaska, the Yukon, Northern Europe and Asia are all showing similar results. There's consistent evidence that large predators help keep populations of large herbivores in check, with positive effects on ecosystem health."

Densities of large mammalian herbivores were six times greater in areas without wolves, compared to those in which wolves were present, the researchers concluded. They also found that combinations of predators, such as wolves and bears, can create an important synergy for moderating the size of large herbivore populations.

"Wolves can provide food that bears scavenge, helping to maintain a healthy bear population," said Robert Beschta, a professor emeritus at OSU and co-author of the study. "The bears then often prey on young moose, deer or elk -- in Yellowstone more young elk calves are killed by bears than by wolves, coyotes and cougars combined."

In Europe, the coexistence of wolves with lynx also resulted in lower deer densities than when wolves existed alone.

In recent years, OSU researchers have helped lead efforts to understand how major predators help to reduce herbivore population levels, improve ecosystem function and even change how herbivores behave when they feel threatened by predation -- an important aspect they call the "ecology of fear."

"In systems where large predators remain, they appear to have a major role in sustaining the diversity and productivity of native plant communities, thus maintaining healthy ecosystems," said Beschta. "When the role of major predators is more fully appreciated, it may allow managers to reconsider some of their assumptions about the management of wildlife."

In Idaho and Montana, hundreds of wolves are now being killed in an attempt to reduce ranching conflicts and increase game herd levels.

The new analysis makes clear that the potential beneficial ecosystem effects of large predators is far more pervasive, over much larger areas, than has often been appreciated.

It points out how large predators can help maintain native plant communities by keeping large herbivore densities in check, allow small trees to survive and grow, reduce stream bank erosion, and contribute to the health of forests, streams, fisheries and other wildlife.

It also concludes that human hunting, due to its limited duration and impact, is not effective in preventing hyper-abundant densities of large herbivores. This is partly "because hunting by humans is often not functionally equivalent to predation by large, wide-ranging carnivores such as wolves," the researchers wrote in their report.

"More studies are necessary to understand how many wolves are needed in managed ecosystems," Ripple said. "It is likely that wolves need to be maintained at sufficient densities before we see their resulting effects on ecosystems."

"The preservation or recovery of large predators may represent an important conservation need for helping to maintain the resiliency of northern forest ecosystems," the researchers concluded, "especially in the face of a rapidly changing climate."

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Wolverine Ecology & Conservation - Yellowstone National Park

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The Northern Rockies Conservation Cooperative (NRCC) has partnered with the U.S. Forest Service, National Park Service, Yellowstone Park Foundation, and others to research wolverine ecology in Glacier & Yellowstone National Parks. These two projects lead to an increased understanding of wolverine distribution and residency, reproductive characteristics, habitat selection, food habits, connectivity of populations, and population parameters such as survival rates, birth rates, and dispersal. Additionally, public education components of these projects foster appreciation and support for wolverine conservation.

Here are excerpts from their Wolverine Conservation in Yellowstone National Park: Final Report

Wolverines in the contiguous United States are a strong concern for federal land managers and the public. The species was designated a candidate species (warranted for listing under the Endangered Species Act, but precluded by work on species of higher priority) by the US Fish and Wildlife Service in 2010. Wolverines are particularly vulnerable to extirpation due to their low numbers and large spatial requirements (Banci 1994; Copeland and Whitman 2003). Wolverine populations in the conterminous United States are small and isolated as compared to those in Canada due to naturally fragmented habitat (Aubry et al. 2007; Ruggerio et al. 2007) and infrequent exchange of individuals between mountain ranges (Cegelski et al. 2003; Kyle and Strobeck 2001, 2002). These attributes contribute to low genetic effective population sizes and low population viability (US Fish and Wildlife Service 2008). Due to its importance for the security and thermoregulation of neonates, spring snow cover may limit the wolverine’s distribution and abundance, yet this habitat component is declining across the species’ geographic range due to global climate change (Aubry et al. 2007; Copeland et al. 2010).

The wolverine is one of the least studied carnivores in North America, particularly in the contiguous United States where it occurs at the southern extent of its range (Ruggiero et al. 2007). Previous reports, surveys, and sightings records suggest that wolverines historically occurred throughout the Greater Yellowstone Ecosystem (Skinner 1927; Smith 1955; Mobley 1962; Hoak et al. 1982; Groves 1988; Consolo-Murphy and Meagher 1995; Robinson and Gehman 1998; Murphy et al. 2004).

The Wildlife Conservation Society is conducting a long-term study in the western and southern portion of the ecosystem (Inman et al. 2007a, 2008). However, little information is available concerning this species’ distribution and ecology in Yellowstone National Park and the adjoining national forests along the park’s northeast, east, and southeast boundary.

Our study objectives were to document (1) the distribution of wolverines in Yellowstone and eastern portion of the ecosystem; (2) their population characteristics, including reproduction, survival, sources of mortality, and food habits; (3) their habitat requirements, particularly those related to natal and maternal denning; and (4) their movements, including any that provide connectivity with populations in other ecosystems. To improve support for its conservation, it was also our aim to increase public awareness of this unique and mysterious carnivore (Appendix 1).

We documented wolverine distribution and population characteristics from 2005 to 2009 in Yellowstone National Park and its neighboring wilderness areas along the park’s east, northeast, and south boundaries by capturing and monitoring radio-marked individuals, and conducting surveys for their tracks during winter. We captured four individuals and collaboratively monitored three others, including two immigrants, that were previously marked by Wildlife Conservation Society biologists in the western portion of the Yellowstone ecosystem.

Wolverines in our study area selected habitats above 2,450 meters (8,000 ft), that is, in the Hudsonian (boreal) life zone, but did not use alpine habitats extensively.

Live-trapping, telemetry data, and surveys for tracks indicated that wolverine numbers and distribution were more limited than expected, despite the fact that two contemporary models estimated an extensive coverage of wolverine habitat in the area. Wolverines occurred in the Absaroka-Beartooth Wilderness along the north boundary of the park, and at the southeast corner (Thorofare region) and the adjoining Washakie and Teton Wilderness areas. When conducting helicopter-based surveys for tracks during winter, we did not detect any wolverines in the park interior, including the portion of the Gallatin Range inside the park; the Washburn and Snake River Ranges; the Central and Madison Plateaus; and the Bechler region. We also did not detect resident wolverines in the North Absaroka Wilderness and the adjoining areas along the east boundary, including the upper Lamar River. Surveys for ungulates in this area during the winter did not indicate that the availability of carrion significantly limited wolverine numbers and distribution, although our anecdotal observations suggested that winter food might be limited in the heavily forested portions of interior Yellowstone.

Wolverine home ranges did not overlap, and radio-marked individuals did not make extra-home range movements to forage in the major ungulate winter ranges in and near our study area, including the Pelican and Hayden Valleys, and the northern winter range. Our limited demographic data suggested that reproductive rates of wolverines were low, that home ranges were large, and that rates of survival were similar to estimates for other populations in the conterminous United States. The dynamics and distribution of our population appeared to be strongly linked to ingress from well-established populations in other parts of the ecosystem, rather than to recruitment of offspring born to our resident females.

We developed and tested a reliable method to rapidly assess wolverine distribution over large areas using helicopter-based searches for tracks during the winter. We were highly successful in finding tracks of resident, radio-marked wolverines during both preliminary tests (searches in 10 x 10 km survey [grid] cells) on a Wildlife Conservation Society study site, and when applying our refined technique to wolverines on our study area. This survey method can be broadly applied to the incised terrain typical of the Rocky Mountains as a first step in assessing wolverine populations, provided that surveys are adequately replicated. We recommend that biologists continue to investigate the factors that limit the growth of wolverine populations, particularly in areas such as ours where models suggest that suitable habitat is abundant.

Rare Wolverine Photographed in Montana

The Wildlife Conservation Society recently released this camera-trap photo of a wolverine retrieving bait placed in a tree in Montana.

The frame upon which the animal climbs is designed so that the unique markings on the underside of the wolverine are revealed to the motion-sensing camera.

Scientists use these markings to identify individual animals and document their distribution and range.

WCS’s eight-year study of wolverines in the Greater Yellowstone Ecosystem has led to a better understanding of wolverine ecology and will help inform conservation strategies so that this rare species can survive despite the 21st century conservation challenges it faces. An estimated 250-300 wolverines remain in the “lower 48,” where they occupy about half of their former range in high alpine peaks of the western United States.

Oregon's lone wolf pack threatened

Journey, an intrepid gray wolf from Oregon's lone wolf pack, made history last year when he traveled more than 1000 miles to become the first wolf in California in nearly a century.

Now Journey's family, the Imnaha pack, is under attack again at home, this time by the Oregon Cattleman's Association, which is pushing a law that would allow for the annihilation of the pack.

Here's why:

A pack of wolves roaming grasslands in Eastern Oregon killed another cow over the weekend.

The Oregon Department of Fish and Wildlife said a yearling heifer was found dead on a ranch east of Joseph in Wallowa County. ODFW officials said the rancher had coraled his 700 cattle Sunday night in a pasture near his home and that the wolves broke in and chased them out, killing a heifer. The wolves returned the next night to the same ranch but no cows were killed.

Russ Morgan, ODFE’s wolf coordinator, said the Imnaha pack has killed 19 cows since spring 2010. Usually wolves go after calves, which are the easiest prey, but the past three cows killed were adults or adult-sized, Morgan said.

“It’s worrying for livestock producers,” he said. “It’s an alarming trend.”

The agency would like to kill two wolves in the pack of at least five animals but a court-ordered stay halted that plan Oct. 5. Wildlife advocates, who took the agency to court, want the state to focus more preserving gray wolves which are protected in Oregon as an endangered species.

But:

Rob Klavins of Oregon Wild said that the number of livestock killed by gray wolves is miniscule compared with the numbers that die being born, in severe weather or from disease. Ranchers also lose cows to thieves.

The Imnaha pack is the first wolf pack in Oregon in more than 60 years. But instead of protecting and celebrating the return of the species, special interests in Oregon are working to eliminate wolves for fear of livestock depredation.

Imnaha Pack alpha male (ODFW)

The wolf pack was the first to establish and produce pups in the state in more than 60 years. While measures should be taken to prevent depredation of livestock, there are better ways to keep cattle safe than killing the family of Journey, who captured the nation's imagination with its thousand-mile expedition to become the first wolf in California in nearly a century.

Last fall, the Center for Biological Diversity and allies won an emergency stay of execution from the Oregon Court of Appeals that stopped the state from killing two wolves in the pack -- a stay that remains in place while the Cattlemen's Association pushes this appalling bill.

Wolves to be Poisoned Over Tar Sands in Canada

Expanding oil and gas production is contributing to the decline of caribou herds in Alberta.


Complete National Wildlife Foundation article

Incredibly, Canada’s proposed solution to habitat destruction from tar sands development is to destroy the wolves that prey on caribou, instead of protecting their habitat.

Two particularly repugnant methods of destroying wolves – shooting wolves from helicopters and poisoning wolves with baits laced with strychnine – would be carried out in response to the caribou declines.

Strychnine is a deadly poison known for an excruciating death that progresses painfully from muscle spasms to convulsions to suffocation, over a period of hours. Wildlife officials will place strychnine baits on the ground or spread them from aircraft in areas they know wolves inhabit. In addition to wolves, non-target animals like raptors, wolverines and cougars will be at risk from eating the poisoned baits or scavenging on the deadly carcasses of poisoned wildlife.


Canada’s Minister of Environment Peter Kent said in September that thousands of Alberta wolves will need to be killed to rescue caribou impacted by tar sands development.

“Culling is an accepted if regrettable scientific practice and means of controlling populations and attempting to balance what civilization has developed. I’ve got to admit, it troubles me that that’s what is necessary to protect this species,” Kent commented.

Simon Dyer of the Pembina Institute estimates that many thousands of wolves could be destroyed over five years under Canada’s proposed plan.

The minister has it backwards. Rather than killing wolves, he should be stopping the habitat destruction and restoring habitat associated with tar sands production. Without healthy habitat, the decline of caribou is inevitable, no matter how wolves are managed. If Canada wants to protect caribou herds, the first priority should be protection and restoration of caribou habitat.

Helicopter Hunt In Idaho?

Reasons given for wolf control action and helicopter use in the Lolo Zone.

Idaho Fish and Game has a study area within the Lolo Zone to collect detailed information on wolves and prey populations in addition to broader-scale information gathered for the entire zone. There are at least 12 packs in the Lolo including five packs that travel back and forth between Idaho and Montana. Fish and Game will continue to collect information to evaluate the effectiveness of control actions in meeting population goals for all big game species. Lolo elk populations have been in decline for years, dating back to the early 1990s. Fish and Game has conducted extensive research that indicates wolf predation is the leading cause of death of adult cow elk and calves older than six months, while black bear and mountain lion predation is the leading cause of death for younger elk calves.

Although Fish and Game’s elk objectives for the Lolo Zone are set below historic population highs to address declines in habitat quality, these objectives aren’t being achieved. Fish and Game has been working with federal land managers for several years to improve habitat in the Lolo Zone. Public hunting of black bears and mountain lions in the Lolo Zone appears to be meeting Fish and Game’s objectives for reducing elk calf predation by these species. Public harvest of wolves in the Lolo Zone, however, is well below objectives for reducing wolf predation on elk. As of December 15, 2011, the public had harvested only 7 wolves.

Fish and Game’s goal is to reduce the wolf population in the Lolo Zone to 20 to 30 wolves in 3 to 5 packs for a period of 5 years to give Lolo elk populations a chance to recover. Assuming public harvest of wolves remains low in the Lolo Zone, Fish and Game will conduct agency control actions through a combination of trapping and aerial control. These actions are consistent with its predation management plan for the Lolo Zone. Fish and Game’s predation management plan is based on research information and data regarding predator and prey populations.

Even while wolves in the Lolo Zone were on the Endangered Species List, there was a process for U.S. Fish and Wildlife to approve reducing local wolf populations to address unacceptable impacts to elk herds. Fish and Game was in the process of obtaining U.S. Fish and Wildlife Service approval for wolf reductions in the Lolo Zone through Endangered Species Act rules when wolves were delisted. Scientific experts outside the agency have reviewed the framework for Fish and Game’s proposal to reduce the Lolo wolf population and underlying research.

Idaho Fish and Game does not have specific details regarding Lolo aerial control actions at this time. Fish and Game will provide information regarding wolf control actions in monthly wolf management updates that will be posted on the Fish and Game website: http://fishandgame.idaho.gov

Documents:

IDFG Lolo Predation Management Plan

IDFG Wolf Management (Harvest Information, Monthly Management Reports)

USDA Wildlife Services . The USDA Wildlife Services Environmental Assessment, evaluating methods for controlling wolf populations in Idaho under the National Environmental Policy Act

Wolves BEHAVIOR, ECOLOGY, AND CONSERVATION

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In the Valley of the Wolves: Wildlife Cinematographer Bob Landis

Emmy Award-winning wildlife cinematographer Bob Landis discusses the making of the film, including the ideal circumstances for filming a predation scene; the importance of spending a vast amount of time in the field; the uniqueness of Yellowstone’s Druid wolf pack, and more.


Full video, Parts 1 and 2:

Watch In the Valley of the Wolves on PBS. See more from Nature.

Watch In the Valley of the Wolves on PBS. See more from Nature.

Are Wolves Saving Yellowstone’s Aspen Trees from Elk?

Previous research has claimed that the reintroduction of wolves to Yellowstone National Park in 1995 is helping restore quaking aspen in risky areas where wolves prowl. But apparently elk hungry for winter food had a different idea.

They didn’t know they were supposed to be responding to a “landscape of fear.”

According to a study set to be published this week in Ecology, a journal of the Ecological Society of America, the fear of wolf predation may not be discouraging elk from eating aspen trees after all.

Previous thinking went like this: Aspen are not regenerating well in Yellowstone National Park. Elk eat young aspen. But wolves eat elk. Elk will learn to avoid high-risk areas that wolves frequent. Plants in those areas – such as aspen – will then get a chance to grow big enough so that elk cannot kill them. Eventually, an entire habitat is restored because of a landscape of fear.

Over the last 15 years, the reintroduction of wolves in Yellowstone was heralded as a great success, not only because it reestablished the species, but also because wolves were expected to help restore a healthier ecosystem through such cascading indirect effects on other species.

But this recent study led by Matthew Kauffman, a U.S. Geological Survey scientist, suggests that aspen are not benefitting from the landscape of fear created by wolves, and that claims of an ecosystem-wide recovery of aspen are premature.

“This study not only confirms that elk are responsible for the decline of aspen in Yellowstone beginning in the 1890s, but also that none of the aspen groves studied after wolf restoration appear to be regenerating, even in areas risky to elk,” said Kauffman.

Because the fear of wolves does not appear to be benefiting aspen, the authors conclude that if the Northern Range elk population does not continue to decline -- their numbers are 40 percent of what they were before wolves -- many of Yellowstone’s aspen stands are unlikely to recover. “A landscape-level aspen recovery is likely only to occur if wolves, in combination with other predators and climate factors, further reduce the elk population,” Kauffman said.

Predators play an important role in ecosystems, said Kauffman, and can influence plants by altering how many herbivores there are (by eating the herbivores) or by changing the behavior of herbivores (deterring them from areas where predators lurk). He adds, however, that considerable scientific debate exists regarding the importance of these two ways in which predators influence their prey. And this is especially true for large carnivores.

To complicate matters, predators use different hunting strategies – there is the sit-and-wait strategy (as with a spider in a web, or a rattlesnake waiting for a mouse to leave its burrow) and the more active, go get ’em strategy (think cheetahs and wolves). “So, given that it takes a lot of energy to avoid a predator – energy that could be used to stave off winter starvation – we wanted to find out whether the prey of active-hunting predators such as wolves demonstrated risk-induced changes in areas where they foraged for food,” Kauffman said.

To do this, the authors analyzed tree rings to discern when, in the last century, aspen stands stopped regenerating, examined whether aspen stands have begun to regenerate now that wolves have been reintroduced to the park and tested whether any differences in aspen regeneration were occurring in areas considered safe or risky for foraging elk. They used a landscape-wide risk map of elk killed by wolves over the first 10 years of wolf recovery. Finally, the authors experimentally fenced in young aspen suckers to compare the protection afforded to them by wolves versus that of a physical barrier that prevented elk browsing.

“The results were surprising and have led us to refute several previous claims regarding interactions among wolves, elk and aspen in Yellowstone,” Kauffman said.

The tree rings showed that the period when aspen failed to regenerate (1892 to 1956) lasted more than 60 years, spanning periods with and without wolves by several decades. “We concluded from this that the failure of aspen to regenerate was caused by an increase in the number of elk following the disappearance of wolves in the 1920s rather than by a rapid behavioral shift to more browsing on aspen once wolves were gone from the park,” said Kauffman.

Surveys of current conditions indicated that aspen in study stands exposed to elk browsing were not growing to heights necessary to make them invulnerable to elk. The only places where suckers survived to reach a height sufficient to avoid browsing were in the fenced-in areas. In addition, aspen stands identified as risky from the predation risk map were browsed just as often as aspen growing in less risky areas.

“This work is consistent with much of what researchers have learned from studying wolves and elk in Yellowstone,” Kauffman said. “Elk certainly respond behaviorally to the predation risk posed by wolves, but those small alterations to feeding and moving across the landscape don’t seem to add up to long-term benefits for aspen growing in areas risky to elk.”

The paper, Are wolves saving Yellowstone’s aspen? A landscape-level test of a behaviorally mediated trophic cascade, will be published online in Ecology this week. Co-authors on the study are Matthew Kauffman (USGS), Jedediah Brodie (University of Montana) and Erik Jules (Humboldt State University).

Resident elk attract wolves to Wyoming rangelands

Wolves in Wyoming and elsewhere in the Rocky Mountain West are often lethally removed when they kill domestic livestock. New research out of the USGS Wyoming Cooperative Fish and Wildlife Research Unit indicates that the migratory patterns of the wolf’s primary prey (elk) can influence wolf predation on cattle. Researchers tracked wolves in areas occupied by migratory and resident elk and recorded the location where wolves killed elk, deer, and cattle. They found that wolves stay close to the growing numbers of resident elk, but kill cattle when pasture rotations cause them to comingle with elk. Study findings point to the need to integrate the management of wolves, elk and cattle on western rangeland

Dramatic Links Found Between Climate Change, Elk, Plants, and Birds

Climate change in the form of reduced snowfall in mountains is causing powerful and cascading shifts in mountainous plant and bird communities through the increased ability of elk to stay at high elevations over winter and consume plants, according to a groundbreaking study in Nature Climate Change.

The U.S. Geological Survey and University of Montana study not only showed that the abundance of deciduous trees and their associated songbirds in mountainous Arizona have declined over the last 22 years as snowpack has declined, but it also experimentally demonstrated that declining snowfall indirectly affects plants and birds by enabling more winter browsing by elk. Increased winter browsing by elk results in trickle-down ecological effects such as lowering the quality of habitat for songbirds.

The authors, USGS Montana Cooperative Wildlife Research Unit scientist Thomas Martin and University of Montana scientist John Maron, mimicked the effects of more snow on limiting the ability of elk to browse on plants by excluding the animals from large, fenced areas. They compared bird and plant communities in these exclusion areas with nearby similar areas where elk had access, and found that, over the six years of the study, multi-decadal declines in plant and songbird populations were reversed in the areas where elk were prohibited from browsing.

"This study illustrates that profound impacts of climate change on ecosystems arise over a time span of but two decades through unexplored feedbacks," explained USGS director Marcia McNutt. "The significance lies in the fact that humans and our economy are at the end of the same chain of cascading consequences."

The study demonstrates a classic ecological cascade, added Martin. For example, he said, from an elk’s perspective, less snow means an increased ability to freely browse on woody plants in winter in areas where they would not be inclined to forage in previous times due to high snowpack. Increased overwinter browsing led to a decline in deciduous trees, which reduced the number of birds that chose the habitat and increased predation on nests of those birds that did choose the habitat.

"This study demonstrates that the indirect effects of climate on plant communities may be just as important as the effects of climate-change-induced mismatches between migrating birds and food abundance because plants, including trees, provide the habitat birds need to survive," Martin said.

The study, Climate impacts on bird and plant communities from altered animal-plant interactions, was published online on Jan. 8 in the journal Nature Climate Change.