The Eurasian grey wolf, Canis lupus lupus, has spread across Germany

Since the year 2000, the Eurasian grey wolf, Canis lupus lupus, has spread across Germany. For Ines Lesniak, doctoral student at the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW), and her colleagues, a good reason to have a closer look at the small "occupants" of this returnee and to ask the question whether the number and species of parasites change with an increasing wolf population. This was the case, because the number of parasite species per individual wolf increased as the wolf population expanded. Furthermore, cubs had a higher diversity of parasite species than older animals. The good news: wolf parasites do not pose a threat to human health. The results of this study were published in the scientific online journal "Scientific Reports" of the Nature Publishing Group.

In the course of a long-term study of wolf health in Germany, the internal organs of 53 wolf carcasses were studied in detail. They came from wolves which had died in traffic accidents or were illegally killed between 2007 and 2014.

"Whereas tapeworms are recognisable with the naked eye, the identification of single-celled Sarcocystis parasites was a real challenge, since the species of this genus do not differ morphologically," explains Lesniak.

According to their developmental cycle, endoparasites can be grouped into two types: Some, such as many tapeworms, infect their hosts directly. Others, such as Sarcocystis parasites, first live in an intermediate host, the prey animal of the wolf, and reach their final host, the wolf, only if the intermediate host has been consumed by the final host. With the faeces of the final host, these parasites are released back into the environment. Potential prey animals of the wolf feed then on vegetation that was previously contaminated with the parasites. The parasites thereby invade the intermediate host and settle in the muscle flesh. Roe deer, red deer and wild boar are such intermediate hosts in central Europe. When these are eaten by a wolf, the parasites infect the final host -- the wolf -- and reproduce in its intestines.

By applying sophisticated molecular genetic analyses, the scientists identified 12 Sarcocystis species in the wolf carcasses. They also found four tapeworm species (cestodes), eight roundworm species (nematodes) as well as one fluke species (trematode). In order to examine parasite infections also in the wolf's large prey species, the team collected internal organs of shot prey animals from hunting parties.

In Germany, wolves mainly feed on roe deer, but also red deer and wild boars. Small mammals, such as hares, voles or mice, are very seldom "on the menu." The identified parasites provide indirect evidence for this insight, since fox tapeworms were found in only one of the 53 wolves. Fox tapeworms are transmitted by mice and can occur in all canids, but particularly frequently in foxes. "Good news," Lesniak says, because the larvae of fox tapeworms can cause severe diseases in humans.

The scientists found that the infestation of wolves with parasites varied during their lifetime. "Cubs carry many more parasite species than yearlings or adults." According to Ines Lesniak, such variation in parasite species prevalence can be explained by the more robust immune system of older wolves. Wolves, just like any other wild canid -- other than domestic dogs -- are never dewormed, after all.

Wolves that died at the beginning of the study period had a lower parasite diversity than those who died later. "The bigger the population, the more often wolves are in contact with each other and their prey, and the more often they became infected with different parasites," Lesniak summarises the results.

Currently, there are 46 wolf packs settled within Germany. A pack consists of the parents as well as the cubs of the current and the previous year and can comprise up to ten individuals. "Genetic analyses conducted by our cooperation partners for this study show that the ancestors of the Central European lowland population, which nowadays ranges from Germany to Poland, originated from Lusatia in eastern Germany," Lesniak says. This population was probably initiated by individuals who migrated from the Baltic region at the beginning of the millennium and settled between southern Brandenburg and northern Saxony. From there, they began to spread across northeastern Germany and southwestern Poland, a process which continues to this day.

"Wolves are shy, wild animals. Thus, contact between people and wolves is rare," Lesniak emphasises. "Nevertheless, hunters should boil the leftovers of shot game thoroughly before feeding this to their hunting dogs, in order to avoid possible parasite infections," warns Lesniak. It is also essential to regularly deworm hunting dogs in regions occupied by wolves.

Occasionally, it has been reported that wolves come closer to residential areas; sheep farmers are complaining about losses. "It may well be that today's wolves have learnt that it is easier to find food closer to humans -- those, who once eradicated their wolf forefathers" presumes Lesniak. Of course, it is more convenient for a wolf to break into a sheep enclosure than to chase roe deer in the forest. Therefore, the implementation of appropriate protective measures of domestic animals is very important and now also financially supported by the government in Germany.

Tigers could roam again in Central Asia

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IMAGE: THIS IS AN ARTIST'S DEPICTION OF A CASPIAN TIGER. view more 

CREDIT: HEPTNER AND SLUDSKIY 1972

Caspian tigers, some of the largest cats that ever lived -- up to 10 feet long and weighing more than 300 pounds -- met a grim end in the middle of the 20th century. 

Until the mid-1960s when they were designated as extinct, they ranged from modern-day Turkey through much of Central Asia, including Iran and Iraq, to northwestern China. The reasons for their extermination are many: poisoning and trapping were promoted by bounties paid in the former Soviet Union until the 1930s; irrigation projects during the Soviet era destroyed the tugay woodlands (a riparian and coastal ecosystem of trees, shrubs and wetlands) and reed thickets that were critical tiger habitat; and the cats' prey disappeared as the riparian habitat vanished. 

But there is a chance that tigers -- using a subspecies that is nearly identical, genetically, to the extinct Caspian -- could be restored to Central Asia.

A study published online in the journal Biological Conservation lays out the options for restoring tigers to Central Asia and identifies a promising site in Kazakhstan that could support a population of nearly 100 tigers within 50 years.

"The territory of the Caspian tiger was vast," said Professor James Gibbs, a member of the research team and a conservation biologist who is director of the Roosevelt Wild Life Station at the College of Environmental Science and Forestry (ESF) in Syracuse, New York. "When they disappeared, the number of nations that hosted tiger populations was reduced by more than half." 

The researchers say introducing tigers in a couple of locations in Kazakhstan won't make a widespread difference immediately but it would be an important first step.

"The idea of tiger reintroduction in Central Asia using the Amur tiger from the Russian Far East as an 'analog' species has been discussed for nearly 10 years. It met with considerable support from the government of Kazakhstan in 2010 during the Global Tiger Forum in St. Petersburg, Russia," said Mikhail Paltsyn, an ESF doctoral candidate who oversaw analytical aspects of the study. 

"But the program needed a strong scientific foundation to evaluate the full habitat potential for tigers and to better explore different possible outcomes of the reintroduction in different scenarios," Paltsyn said. 

In addition to Paltsyn and Gibbs, the research team includes ESF scientists Liza Yegorova, a recent master's graduate; Dr. Igor Chestin, director of WWF-Russia; and Dr. Olga Pereladova, director of WWF Central Asia Program. Paltsyn is a member of the International Union for Conservation of Nature Cat Specialist Group and has served as a consultant with the World Wide Fund for Nature (WWF) and United Nations Development Programme.

The scientists say two factors have combined to raise the possibility of restoring tigers to the Ili-Balkhash region of western Kazakhstan:

* The breakup of the Soviet Union and introduction of market economies in newly established states has led to the recovery of tiger habitats in some areas as state-sponsored agricultural programs along rivers were abandoned.
* Recent work in phylogenetics (the study of evolutionary history) indicates Caspian tigers were closely related to Amur tigers that still exist, making Amur tigers a likely "analog" species for restoration of tigers to the region. 

But Paltsyn laid out the challenges that would need to be addressed before tigers start roaming the landscape again. 

"First, it is necessary to stop riparian zone degradation caused by uncontrolled fires. Second, it is vital to restore wild ungulate (broadly defined as a hoofed mammal) populations in the area. That, alone, could take five to 15 years," Paltsyn said. "Third, human safety and socio-economic benefits for local populations need to be addressed to provide a sustainable future for both tigers and people. And, finally, water consumption from the Ili River needs to be regulated in both Kazakhstan and China to support sufficient water level in Balkash Lake for tugay and reed ecosystems - the main tiger habitat. However, WWF and the government of Kazakhstan seem to be ready to deal with all these difficult issues to bring tigers back to Central Asia." 

Tiger reintroduction has support from the Kazakhstan government and local communities because of potential economic benefit from wildlife tourism, small-business growth and employment opportunities at Ili-Balkhash Nature Reserve.

In the study, the researchers analyzed scientific literature that revealed Caspian tigers once lived in an area about 800,000 to 900,000 square kilometers in size (between 300,000 and 350,000 square miles), mostly within isolated patches of riparian ecosystems (land along rivers or streams). Generally, two or three tigers occupied an area that covered about 100 square kilometers (about 40 square miles).

Spatial analyses based on remote sensing data indicated that options for Amur tiger introduction are limited in Central Asia. But at least two habitat patches are potentially suitable for tiger re-establishment, both in Kazakhstan. When the researchers considered current land use and the low density of the local human population, they found the most promising site is the Ili River delta and adjacent southern coast of Balkhash Lake. The river flows from northwestern China into southeastern Kazakhstan; it drains into Balkhash Lake, the 15th largest lake in the world. 

The team identified about 7,000 square kilometers (about 2,700 square miles) of suitable habitat. Population models for animals that tigers typically prey on -- wild boar, Bukhara deer and roe deer -- suggest the area could support a population of between 64 and 98 tigers within 50 years if 40 to 55 tigers are introduced. 

The Amur tiger is apparently the only subspecies that has significantly increased in number in the last 65 years. Scientists estimate some 520 to 540 still live in the wild. Moving some of them from the Russian Far East to the Ili River delta could be enough to eventually establish a wild population in 50 years, and would not harm the Russian population, the study says.

Around the world, similar relocation programs have worked for cat populations. The study says: "... case studies suggest high adaptive potential of big cats to novel environments. We know of no large cat translocation programs that failed strictly due to maladaptation of source population to environment of release."

How Wolves Change Rivers

Arguments for removing gray wolves from endangered species protection are incorrect

Researchers from Princeton University and the University of California-Los Angeles who investigated the genetic ancestry of North America's wild canines have concluded that the U.S. Fish and Wildlife Service's scientific arguments for removing gray wolves from endangered species protection are incorrect.

The study, which contradicts conventional thinking, finds that all of the continent's canids diverged from a common ancestor relatively recently and that eastern and red wolves are not evolutionarily distinct species but a hybrid of gray wolf and coyote ancestry. The study will appear in the journal Science Advances.

Gray wolves once ranged across much of the United States but were hunted to near-extinction in the late 1800s and early 1900s. In 1973, the U.S. Fish and Wildlife Service listed the gray wolf under the Endangered Species Act, in part, because its geographic range once included the Great Lakes region and 29 eastern states. Since then, gray wolves have rebounded due to protections, reintroduction and natural repopulation, making wolf recovery in the West one of the most successful efforts under the ESA. Gray wolves also still live in the Great lakes area but not in the 29 eastern states. The red wolf also was protected under the ESA as a distinct species in 1973, but the eastern wolf, which was only recently recognized as a distinct species, is not protected.

The Fish and Wildlife Service will decide this fall whether to remove the gray wolf from protection, drawing renewed attention to the conflict between conservationists, ranchers, hunters and others who see the iconic predator either as a threat or as part of a healthy ecosystem. The agency says the gray wolf should be delisted because the eastern wolf - not the gray wolf - lived in the Great Lakes region and eastern states. Essentially, the presence of the eastern wolf, rather than the gray wolf, in the eastern United States would cause the gray wolf's original listing to be annulled. With the exception of the Mexican wolf, the gray wolf would lose protection from its entire North American range under the proposed rule change.

In their new study, lead author Bridgett vonHoldt, an assistant professor in ecology and evolutionary biology at Princeton, and her colleagues analyzed the complete genomes of 12 pure gray wolves (from areas where there are no coyotes), three pure coyotes (from areas where there are no gray wolves), six eastern wolves (which the researchers call Great Lakes wolves) and three red wolves.

Results showed that eastern and red wolves are not evolutionary distinct species but the result of a relatively recent interbreeding: Eastern wolves are about 75 percent gray wolf and 25 percent coyote, while red wolves are about 25 percent gray wolf and 75 percent coyote.

"We found no evidence for an eastern or red wolf that has a separate evolutionary legacy," vonHoldt says. "These results suggest that arguments for delisting the gray wolf are not valid."

The researchers also conclude that the ESA should protect hybrid species because interbreeding in the wild, thought to be uncommon when the ESA was passed in 1973, has been shown to be common and may not be harmful.

"Our findings demonstrate how a strict designation of a species under the ESA that does not consider genetic admixture can threaten the protection of endangered species," vonHoldt says. "We argue for a more balanced approach that focuses on the ecological context of genetic admixture and allows for evolutionary processes to potentially restore historical patterns of genetic variation."

Management efforts for elk and deer may not benefit all wildlife

COLORADO STATE UNIVERSITY

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IMAGE: THIS IS TRAVIS GALLO, PH.D. STUDENT, COLORADO STATE UNIVERSITY. view more 

CREDIT: COLORADO STATE UNIVERSITY

It's no surprise that most conservation efforts in the United States focus on animals that are hunted. But a new study from Colorado State University researchers found that improving habitats for game animals has mixed consequences for other animals in the same setting. 

The study calls for more scrutiny of and a more holistic approach to current management efforts.

Hunting provides substantial economic benefits for states. Deer and elk hunters in Colorado, for example, must apply for permits annually. A deer license for non-residents runs $432; a permit for in-state residents is $43. A license to hunt elk is nearly $500 for non-residents; the in-state charge is $48. Nearly $2 million from these fees support wildlife management and public land conservation in the state each year.

"There's this notion that habitat management that's good for game species is good for all wildlife," said Travis Gallo, Ph.D. student in the Department of Fish, Wildlife and Conservation Biology, and lead author of the study. "There's a lot of money that goes into habitat management for game species, and we wanted to see if there were any synergies between game management and conservation of species that were not the target of management actions."

While conducting a review of published papers, Gallo said that he and Associate Professor Liba Pejchar, also in the Department of Fish, Wildlife and Conservation Biology, switched gears once they saw the lack of scientific research on the topic. The duo ended up writing an opinion piece or perspectives essay on the issue. 

"We found only 26 studies that measured the direct and indirect effects of game management efforts on non-game animals," said Gallo.

Among the studies that did measure the effects of game management on non-game species, they found both positive and negative effects: a study of sage grouse management in the Western U.S. found that conservation efforts would likely protect 13 songbird species, while a study in Spain found that an increased abundance in wild boar, red deer and aoudad sheep decreased resources for native species. 

The team also found instances where there were no effects. For example, a study that looked at prescribed fire on lizard abundance in central Texas found no short-term effect on other species.

Gallo said that one way to even the management playing field is to create new funding sources for wildlife conservation. The federal Pittman-Robertson excise tax -- which was implemented in 1937 -- has successfully raised more than $10.1 billion from sales on sporting goods that involve hunting, like ammunition and guns, fishing rods and reels. In 2009, following a similar model, a group of more than 6,300 state fish and wildlife agencies, biologists, hunters, birdwatchers and others proposed the Teaming with Wildlife Act, which would have provided additional funding for wildlife preservation through a small tax on all outdoor gear, including camping gear, binoculars and outdoor apparel. This bill, however, failed to pass through Congress.

Gallo said that there's talk in the conservation community about reviving this sort of proposal. "A tax like this would not only increase funding for conservation, but it may create a sense of investment by those people that are now helping pay for conservation," he said.

Gallo -- who will graduate in May -- said his research provides a good example, and hope, for the type of holistic approach that is needed. 

"My research is piggy-backed on a mule deer experiment in northwestern Colorado," he said. "Colorado Parks and Wildlife was removing pinyon-juniper trees to increase the shrubs and grasses that mule deer like to eat. We collaborated with them and added another layer of research to assess the effects that this management may have on all the other birds and mammals in the area."

"The hunting and fishing communities contribute a lot of money and effort to wildlife management," he added. "If you can find synergies between management for hunted species and conservation for biodiversity, we would be more effectively and holistically managing the land."

The article, "Improving habitat for game animals has mixed consequences for biodiversity conservation," was published in advance online in Biological Conservation. The study will appear in the May print issue of the journal.

A changing season means a changing diet for bison

North American bison adjust their diet seasonally in order to take full advantage of the growing season when grasses become less nutritious, a new study led by researchers at the University of Colorado Boulder has discovered.

The findings, which were recently published in the journal PLOS ONE, indicate that bison are not entirely reliant on grass for their nutritional needs and can selectively expand their foraging to include woody shrubs and flowering plants during the spring and fall.

The study sheds new light on variations in the large herbivore's eating habits and may have future implications for management and conservation of bison in Colorado and across the American West.

"We wanted to know if bison might change what they eat as the season goes on and how that affects the microbial composition of their gut," said Gaddy Bergmann, a doctoral candidate in the Department of Ecology and Evolutionary Biology at CU-Boulder. "This study shows that it may be beneficial for the species to have other plants, bushes, and trees available to browse from."

The 166-day study conducted in 2011 sampled a herd of roughly 300 bison living in the Konza Prairie Biological Station in the Flint Hills area of northern Kansas. Bison were reintroduced to the protected native tallgrass sanctuary in 1987.

By sequencing the plant and bacterial DNA found in the bison's fecal samples, researchers at CU-Boulder were able to identify the types of plants that the bison were consuming over time. The researchers found that the bison are willing and able to consume higher quantities of woody shrubs in the early spring and in fall when their preferred menu item--fresh grass--is less available.

The researchers then identified benign gut microbes present in the bison's lower digestive tract and traced how the abundance of those microbes changed over time. Some bacteria became more abundant during the growing season as the bison switched to more energy-rich foods in the summer and autumn.

Other grazing animals throughout the world, such as elk and wildebeests, migrate over long distances in order to follow their food supply. Historically, bison did so as well, but are more sedentary in their range today, making them more susceptible to seasonal changes in vegetation.

While an estimated 20 to 30 million bison once roamed the North American landscape, hunting and habitat encroachment reduced the population to just a few thousand by the end of the 1800s.

Cougars, aka mountain lions and pumas, likely to recolonize portions of habitat in the middle part of the United States

A groundbreaking new study shows that cougars, also known as mountain lions and pumas, are likely to recolonize portions of habitat in the middle part of the United States within the next 25 years. It is the first study to show the potential "when and where" of the repopulation of this controversial large predator.

The study, led by researchers at the University of Minnesota and Southern Illinois University Carbondale, will be published soon in the international journal Ecological Modelling.

This is the first, large-scale population viability study on cougars. The research examined more than 40 years worth of data on demographics and geographical information on more than 3 million square kilometers to determine possible areas of population establishment. The researchers specifically looked at the female dispersal since population settlement is dependent upon the arrival of females in a given area.

"We didn't just look at where they are now, but where they could go," said study author Michelle LaRue, a University of Minnesota research associate in the College of Science and Engineering's Department of Earth Sciences. "These are predictive models, but we feel that our study could be an important tool for conservation of this species and education about a large carnivore that can sometimes incite fear."

Breeding populations of cougars are already living in the Black Hills of South Dakota, and researchers noted four breeding populations in North Dakota and Nebraska. The new study shows that cougars could be expected in the next two decades in Arkansas, Missouri and Nebraska with the potential to sustain existing populations in the Dakotas and Nebraska.

Historically, cougars were once one of the most widely distributed land mammals on earth, ranging from the Atlantic to Pacific oceans and from northern British Columbia to southern Chile. In the United States, the cougars were pushed back to the American West with the arrival of European settlers. Although they have been extirpated for more than 100 years, cougars have been reported in the middle part of the U.S. over the past two decades with more than 800 instances of confirmed cougar presence from 1990-2015.

"The reason cougars used to exist across the country and now they don't is because of people," said study co-author Clayton K. Nielsen from Southern Illinois University Carbondale's Cooperative Wildlife Research Laboratory and Department of Forestry. "Now that this large carnivore is expected to come back into new areas, we need have a clear plan for education and conservation."

The next step is to examine human acceptance and attitudes toward the repopulation of cougars, said LaRue, who is also the executive director of the Cougar Network, a nonprofit research organization.
"We now have the information necessary for government agencies to plan for ecosystem-based management and societal attitudes toward the recolonization of this predator," LaRue said. "Given that cougars are expected to inhabit areas where they haven't been for more than 100 years, this will pose considerable challenges for wildlife managers and the general public in the future."