Wildlife Sciences

Predator-Mediated Competition

Charles E. Kay. 2010. Predator-Mediated Competition: What happens when there is a second, alternative prey in a system? Muley Crazy, July/August 2010.

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In systems with a single predator and single prey, the predator cannot generally take the prey to extinction due to declining return rates — that is the predators usually starve to death before they can find the last few prey. So while mountain lions, for example, can have a negative impact on mule deer, the cats can only take the deer population so low before the lions begin to run out of food and increasingly turn to killing each other. But what happens when there is a second, alternative prey in a system? Counter intuitively, the additional prey species does not buffer, or reduce, the predation pressure on the first prey animal. Instead, fueled by alternative prey, the predator takes the more vulnerable species to even lower levels. This is called predator-mediated or apparent competition and where this occurs habitat and habitat improvements are largely irrelevant, contrary to what most biologists would have you believe.

A classic example of predator-mediated competition is now playing itself out in Yellowstone National Park. For over 60 years, 600 to 700 food-limited elk wintered in the thermal areas along the Firehole, Gibbon, and Madison Rivers in the west-central portion of the park. With the arrival of introduced wolves, however, the elk population began a precipitous decline with researchers predicting extinction — see The Ecology of Large Mammals in Central Yellowstone. The wolves have been able to do this because they have bison as an alternative prey. In fact, if the elk did not have a partial refugia by fleeing into the depths of the Madison River when confronted by wolves, the elk would already be extinct. The habitat is still there, after all this is a national park, but the elk are all but gone.

Similarly, moose-fueled wolves are in the process of eliminating mountain and woodland caribou across the length and breadth of Canada. While in Alaska, wolves fueled by salmon, yes salmon, have taken black-tailed deer, moose, and caribou to very low levels — much lower then if the wolves did not have salmon as an alternative prey. In Nevada, mountain lions that prey on wild horses have a much greater impact on mule deer than cougar populations without feral equines as alternative prey. It has also been reported that mountain lions have taken bighorn sheep to near extinction on several western ranges where the cats subsist on alternative prey.

In many parts of the West, white-tailed deer and mule deer are sympatric; that is the two species occupy the same areas. Researchers in Alberta have identified predator-mediated competition as a key reason mule deer are declining. Due to behavioral differences, mule deer are more vulnerable to coyote predation than are whitetails. But by preying on both mule deer and whitetails, the coyotes are able to exert much greater predation pressure on mule deer, then if mule deer were the canids only prey. Again the addition of a second prey species, whitetail deer, allowed the predator, coyotes in this case, to have a much greater impact on the more vulnerable prey, mule deer.

While in British Columbia, predator-mediated competition between whitetails, mule deer, and mountain lions has been documented. Again, mule deer are the more vulnerable prey, but by subsisting mainly on whitetails, the cats are able to take mule deer populations to very low levels — much lower than if whitetails were not present. Whitetail-fueled cougars have also been identified as the factor driving British Columbia’s southern, mountain caribou to extinction. Similarly, in Canada’s Banff National Park, elk-fueled wolves have been instrumental in the elimination of both mountain caribou and moose.

Which brings us to the question of predator-mediated competition between ever-increasing numbers to elk in the West and declining mule deer populations. By subsisting on elk, could mountain lions be taking mule deer numbers even lower? Given the fact that mule deer are easier for cougars to kill than elk, predator-mediated competition is certainly possible. Although no one has specifically studied this problem, work that I have been doing for San Juan County in southeastern Utah does shed some light on this issue.
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The Art and Science of Counting Deer

Charles E. Kay. 2010. The Art and Science of Counting Deer. Muley Crazy Magazine, March/April 2010, Vol 10(2):11-18

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It is the simplest of questions and upon which all management is based. It is also the first thing most hunters want to know. How many deer are there? The answer? Well, there are no answers, only estimates. In addition, one needs to understand the difference between precision and accuracy. Think of precision as shooting a five-shot, half-inch group at 100 yards, but the group is 20 inches high and to the right. The shots have been very precise, almost in the same hole, but they were not accurate because they were far from the center of the target. Accuracy is hitting the bullseye. So, an estimate can be precise without being accurate. Estimates that are both precise, low variation, and accurate, close to the true number, are very difficult and very expensive to obtain. Moreover, all population estimates contain assumptions, as well as sampling errors and statistical variation.

Since the advent of modern game management, various methods have been developed to count wildlife. Entire books have been written on the subject and there are enough scientific studies to fill a small library. Here, I will discuss only the techniques that have been, or are commonly used to estimate the number of mule deer and elk on western ranges. This includes ground counts, aerial surveys, population models, pellet-group counts, and thermal imaging.

The oldest and simplest method is ground counts. As the name implies, these are simply counts conducted on foot, horseback, or from vehicles by either one or more observers. While relatively inexpensive, this method is neither precise nor accurate. There is the problem of double counting when the deer run over the hill into the next canyon that has not yet been surveyed and under counting when animals are hidden from view by vegetation or topography. Today, ground counts are seldom used to estimate herd numbers but they are still commonly employed to estimate fawn:doe ratios or buck:doe ratios under the assumption that doe, fawn, and buck sighting rates are similar, which they are not. If bucks are more difficult to see than does because of the habitat the males occupy, or their behavior, ground counts will underestimate the number of bucks.

Due to the shortcomings of ground counts, wildlife biologist were quick to take to the air, first in airplanes and later in rotary aircraft. To make a long story short, counts from helicopters are more accurate than population surveys from fixed-wings. Any aerial count, though, is subject to errors, because even from the air you do not see all members of a population, be they mule deer or elk. This is what, in the scientific literature, is known as sightability bias. Even in experiments where livestock have been placed in flat, grassy pastures, aerial observers fail to record all the animals.

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The Kaibab Deer Incident: Myths, Lies, and Scientific Fraud

Charles E. Kay. 2010. The Kaibab Deer Incident: Myths, Lies, and Scientific Fraud. Muley Crazy Jan/Feb 2010 (posted with permission of the author).

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The North Kaibab, or simply the Kaibab, is famous for producing large-antlered, record-book mule deer. The Kaibab historically, however, is also noted for something else — controversy! At least one book has been written on the Kaibab Deer Incident, as well as scores of scientific reports and monographs. The Kaibab figures prominently in the history of mule deer management in the West and even the U.S. Supreme Court has weighed-in on the Kaibab. Although the story has changed over the years, the Kaibab is still discussed in wildlife textbooks and the ghost of the Kaibab stalks wildlife management to this day.

The Kaibab Plateau is bordered on the south by the Grand Canyon, on the west by Kanab Canyon, and on the east by Houserock Valley. The plateau, which is entirely in Arizona, slopes gently downward to the north and ends near the Utah stateline. The plateau reaches a height 9,200 feet and although the Kaibab receives abundant snow and rainfall, surface water is exceedingly rare due to area’s geology. Winter range is abundant on the Kaibab, while summer range is more limited-the exact opposite of most western situations. Approximately two-thirds of the mule deer on the Kaibab winter on the westside with the remaining deer wintering to the east. There is very little movement of mule deer into Utah. Thus, the deer herd on the Kaibab is essentially an insular population with little immigration or emigration. Cliffrose is the most important browse species on the plateau’s shrub-dominated winter ranges.

The Kaibab was established as a Forest Reserve in 1893 and in 1906 was designated as the Grand Canyon National Game Preserve by President Theodore Roosevelt. Today, the southern end of the plateau is in Grand Canyon National Park, while the rest of the area is managed by the U.S. Forest Service. When the Kaibab was declared a game preserve in 1906, hunting was prohibited and the federal government began an extensive predator control program. Between 1907 and 1923, an average of 40 mountain lions, 176 coyotes, 7 bobcats, and 1 wolf were killed each year. In all, only 30 wolves were ever killed by government agents on the Kaibab. Instead, the main predators were mountain lions and coyotes. The Forest Service also reduced the number of livestock permitted to graze the plateau.

In response to those measures, the mule deer herd irrupted from around 4,000 animals in 1906 to an estimated 100,000 head in 1924. As might be expected, the growing deer population severely overgrazed both the summer and winter ranges. This lead to a number of studies and reports, as well as a dispute between the federal government and the state of Arizona. In short, the Forest Service said that the deer herd needed to be reduced to prevent further range damage but the state refused to open the area to hunting. In response, the federal government claimed that it could kill deer on the Kaibab to protect habitat without a state permit. Needless to say, Arizona objected and the ensuing legal battle made it all the way to the U.S. Supreme Court.

The Supreme Court agreed that the Kaibab deer herd had exceeded the range’s carrying capacity and that overgrazing by mule deer had denuded public lands. The Court also sided with the federal government in ruling that the Forest Service could authorize hunting on the Kaibab without state approval. This legal precedent still stands and means that when push come to shove, the federal government can control wildlife populations on public lands. Arizona had no alternative but to capitulate, but it was too late because the plateau’s mule deer had experienced a major die-off and by 1931 fewer than 20,000 animals were left.

For years, the Kaibab deer irruption, overgrazed range, and subsequent die-off were cited in wildlife textbooks as a classic example of what happens when predators are controlled and hunting eliminated. “The Terrible Lesson of the Kaibab” became a cornerstone of modern game management and an example of why hunters were needed to harvest surplus animals. Even Aldo Leopold cited the Kaibab in his study of mule deer overgrazing on western ranges. This interpretation of the Kaibab Deer Incident was accepted as fact for over 40 years until New Zealand biologist Graeme Caughley questioned its validity in a 1970 paper published in Ecology-the scientific journal of the Ecological Society of America. Caughley’s reanalysis of the Kaibab Deer Incident involved primarily published mule deer population estimates. In a later paper, Caughley admitted that he had never set foot on the Kaibab and that he had conducted his reanalysis from a desk 10,000 miles away! Caughley cautioned that his “interpretation may therefore be wrong.”

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Wolf Predation: More Bad News

Charles E. Kay. 2008. Wolf Predation: More Bad News. Muley Crazy, Sept/Oct 2008 (posted with permission of the author).

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As I explained in an earlier article, pro-wolf advocates are now demanding 6,000 or more wolves as one interbreeding population in every western state. Pro-wolf advocates also claim that predation, in general, and wolves in particular have no impact on prey populations. Recent research by Dr. Tom Bergerud and his colleagues, however, paints an entirely different picture and serves as a poignant example of what will happen to the West’s mule deer if pro-wolf advocates have their way.

Woodland and mountain caribou have been declining throughout North America since European settlement. Many attribute the decline to the fact that caribou must feed on aboral or terrestrial lichens during winter, a food that is being destroyed by logging, forest fires, and other human activities; i.e., modern landuse practices are to blame. While others attribute the decline to predation by wolves and other carnivores. To separate between these competing hypotheses, Dr. Tom Bergerud and his co-workers designed a series of simple but elegant experiments and have now accumulated 30 years of data.

In the northern most arc of Lake Superior lie a cluster of seven major islands plus smaller islets. The Slate Islands are five miles from the mainland at their nearest point and only twice during the last 30 years has winter ice bridged that gap. Terrestrial lichens are absent, plus the islands have been both logged and burned, making them unfit for caribou according to most biologists. The Slate Islands lack wolves, black bears, whitetailed deer, and moose, but caribou are indigenous. As a companion study, Bergerud and his associates chose Pukaskwa National Park, which stretches for 50 miles along the north shore of Lake Superior. In contrast to the Slate Islands, Pukaskwa has an abundance of lichens, which are supposed to be a critical winter food for caribou, but unlike the Slate Islands, Pukaskwa is home to wolves, bears, moose, and whitetails. Woodland caribou are also present.

So we have islands that are poor caribou habitat, but which have no predators, versus a nearby national park that is excellent caribou habitat but which contains wolves. Now according to what many biologists and pro-wolf advocates would have you believe, habitat is the all important factor in maintaining healthy ungulate populations, while predation can largely be ignored. Well, nothing could be further from the truth. Habitat it turns out, is irrelevant and ecologists have been, at best, braindead for years.

Despite the supposedly “poor” habitat in the Slate Islands, Bergerud and his research team recorded the highest densities of caribou ever found anywhere in North America. Moreover, those high densities have persisted since at least 1949 when the herd was first censused. More importantly, the density of caribou in the “poor” habitat, but predator-free, Slate Islands was 100 times that in Pukaskwa National Park where predators hold sway. 100 times or 10,000% more caribou per unit area. A significant difference by any objective standard.

Then during the winter of 1993-94, a natural experiment occurred when Lake Superior froze and two wolves crossed to the Slate Islands. Within days, the two wolves proceeded to cut through the Slate Island caribou like a hot knife through butter. Because caribou, like mule deer, are exceedingly susceptible to wolf predation. Only when the two wolves disappeared did caribou numbers recover.

A second set of manipulated experiments was conducted when Bergerud and his associates transplanted Slate Island caribou to adjoining areas with and without wolves. A release to Bowman Island, where wolves and moose were present, failed due to predation. A second release to Montreal Island doubled in numbers until Lake Superior froze and wolves reached that island. A third release was to Michipicoten Island where wolves were absent but so too were lichens. Despite the “poor” habitat, those caribou increased at an average annual rate of 18% for nearly 20 years. A fourth release to Lake Superior Provincial Park on the mainland failed due to wolf predation. Thus, the data are both conclusive and overwhelming. Habitat is largely irrelevant because caribou numbers are limited by wolf predation. Bergerud goes so far as to say that managers have wasted the last 50 years measuring lichens! Remove the wolves and you have 100 times more caribou, even on supposedly “poor” ranges.

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The Complexities of State Management of Wildlife Under Federal Laws

Budge, Randy*. 2009. The Complexities of State Management of Wildlife Under Federal Laws. Conference of Western Attorneys General, Aug 3-5,2009, Sun Valley, Idaho.

*Randy Budge is an attorney and an Idaho Fish and Game Commissioner. This paper represents his personal views and options, not necessarily that of the entire Idaho Fish and Game Commission or the Idaho Department of Fish and Game.

Full text [here] (4.5 MB)

Selected excerpts:

INTRODUCTION

By far the greatest conservationist of our times was President Theodore Roosevelt, who was driven by a passion to protect wildlife for future generations:

“Wild beasts and birds are by right not the property of the people who are alive today, but the property of the unknown generations whose belongings we have not right to squander.”

In an incredible feat to restore dwindling wildlife and protect wild lands in the early 1900s, Roosevelt was instrumental in bringing under federal protection 230 million acres in the form of 150 national forests, 50 national wildlife refuges, 5 national parks and 18 national monuments. This amounted to an incredible 84,000 acres for each day he was in office. …

A tension has always existed between the rights of the states to manage the wildlife within their borders and the right of the federal government to restrict the taking of wildlife or to otherwise manage wildlife in the national interest. The history of federal and state wildlife legislation exhibits an intricate dance over jurisdiction and the right to manage wildlife.

State wildlife laws are based on the principle states own the wildlife within their borders to be held “in trust” for their citizens. Accordingly, the states have primarily shouldered the responsibility to manage wildlife, and have a proven track record of success. In my opinion, the states are far better suited to manage wildlife within their borders than the lumbering and detached federal bureaucracy because the states are better able to monitor and respond to wildlife needs and threats, and to establish cooperation with landowners and other agencies while recognizing the social values of the residents that regularly interact with wildlife.

Federal wildlife laws generally preempt state laws only when necessary to manage or conserve wildlife species that occupy multiple states. Preemption of state law is an area of considerable complexity to be addressed by a later speaker, so further discussion here is omitted. It should be noted, however, that state laws often expressly include or complement Federal laws such as the Endangered Species Act, whose list of endangered species is usually adopted in full by states in their own legislation of endangered and threatened species. …

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Range Reference Areas and The Condition of Shrubs on Mule Deer Winter Ranges

Charles E. Kay. 2009. Range Reference Areas and The Condition of Shrubs on Mule Deer Winter Ranges. Muley Crazy Magazine. Vol 8(1):35-40.

Dr. Charles E. Kay, Ph.D. Wildlife Ecology, Utah State University, is the author/editor of Wilderness and Political Ecology: Aboriginal Influences and the Original State of Nature [here], author of Are Lightning Fires Unnatural? A Comparison of Aboriginal and Lightning Ignition Rates in the United States [here], co-author of Native American influences on the development of forest ecosystems [here], and numerous other scientific papers.

Full text:

After predator control, range management is the key to maintaining healthy populations of mule deer and other wildlife. It is not just habitat, but the condition of that habitat. For instance, how do you tell if a range is being overgrazed? One way is to establish what are called range reference areas. There are a few places that have never been grazed by livestock, such as steep-sided mesa tops, where the vegetation can be compared with nearby grazed areas. Unfortunately, there are very few places in the West that have never been grazed by livestock and there are even fewer that deer and elk cannot reach. So in most areas it is necessary for managers to create their own range reference areas by building exclosures, which they have been doing for years.

If you are working in a national park or on a winter range where livestock use is prohibited, it is a relatively simple matter to build an 8-foot tall fence around a representative plant community, such as willows, aspen, grasslands, or upland shrubs. Then by measuring the vegetation inside and outside the exclosure on permanent sampling plots over time, you can determine what, if any, impacts wildlife are having on the range. It is also important to establish permanent photopoints when the exclosure is first erected.

If on the other hand, you are working on BLM or Forest Service lands that are grazed by livestock and wildlife, the design of the exclosure is a little more complicated. One part, termed the total-exclusion plot, is still high-game fenced to exclude both livestock and wildlife, while an adjacent area, called the livestock-exclusion plot, is fenced in such a manner that livestock are excluded but mule deer and/or elk can jump the low fence and graze/browse by themselves — please see the accompanying photo. Unfenced adjoining areas are grazed by both livestock and wildlife. Thus by measuring the vegetation in all three areas — total exclusion, livestock-exclusion wildlife-only use, and joint use — you can determine, what vegetation changes, if any, are being caused by wildlife separately from those caused by livestock. The total-exclusion portion of the exclosure can also be used to tell if climatic variation, disease, or insects are causing certain plants to decline.

As you might have guessed, the latter type of range reference area is called a three-part exclosure because vegetation conditions are measured under three different grazing treatments. During the 1950’s and 1960’s when mule deer populations were at all time highs, a series of three-part exclosures were built on BLM and Forest Service allotments throughout the West. Unfortunately the Federal land management agencies have no nation-wide program to maintain those exclosures and many have fallen into disrepair, which is extremely shortsighted. Because without long-term range reference areas there is no way to determine what is happening on our public lands.

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The Return of Caribou to Ungava

A.T. Bergerud, Stuart N. Luttich, and Lodewiih Camps. 2007. The Return of Caribou to Ungava.
McGill-Queen’s University Press, Montreal, QU.

Review by Charles E. Kay, Utah State University, from the Canadian Field-Naturalist, Vol. 121, No. 2, April-June 2007

This is the most comprehensive book on caribou ecology and predator-prey relationships that has appeared in many years, perhaps ever. Not only is the research seminal, but the authors systematically dismantle paradigms that have been in vogue for years. According to the authors, caribou biologists have wasted the last 50 years measuring lichens on winter ranges, when they should have been documenting plant production on summer ranges. Wolves, along with human hunters, both limit and regulate caribou populations, not habitat. Food on the summer range only regulates at high densities and only after the range has been overgrazed. Wolves are driving Woodland and Mountain Caribou to extinction. Caribou populations where Wolves are absent maintain densities 100 times greater than predated herds. The reason arctic Caribou migrate to barren ground calving areas is to avoid Wolves tied to den sites at treeline. Even so, if it were not for periodic rabies epidemics, migratory caribou populations would be severely limited by wolf predation. Volcanic eruptions half a world away trigger population declines in arctic Caribou at high densities. And this is just for starters.

The book chronicles the history of the George River Caribou in Labrador and Quebec from near extinction during the early 1900’s to an estimated 600,000 animals before the herd declined. The authors explore the various hypotheses that have been proposed to explain these fluctuations, and present dataset after dataset to separate between competing explanations. In addition, the authors discuss virtually every other caribou population that has been studied in North America, Scandinavia, and beyond, including the difference between migratory and sedentary herds, which is key to understanding this species’ ecology.

To the south of Ungava are small non-migratory populations of Woodland Caribou that are being driven to extinction by wolf predation. But in reality, Moose and Whitetails are to blame. Historically, these areas sustained low-density, widely-spaced Caribou that in and of themselves could support few or no Wolves. Moose and Whitetails were absent. But since the early 1900’s, Moose and Whitetails have extended their range providing alternative prey for Wolves, where none existed before. The Wolves then drive the more vulnerable Caribou ever downward. That is to say, the addition of alternative prey did not buffer predation on Caribou, but instead increased predation pressure contrary to what many people would expect. But that is not the most intriguing part.

Why were Moose and Whitetails absent historically and prehistorically? The authors contend that logging changed coniferous forests to secondary deciduous species favored by Moose and Whitetails. In this I believe they erred because fire history data indicate there was always a strong deciduous component in those forests. Besides, Moose and Whitetails can survive on a winter diet of Balsam Fir, as they do on Isle Royale and Anticosti Island. Instead, I believe that native hunters once kept eastern moose populations in check, as I know native hunters did in western North America where there are more Moose today than at any time in the last 12,000 years - - see Alces 33:141-164. Historically and prehistorically, native hunters extirpated Moose over large areas because, like the Wolves discussed above, humans had a multitude of alternative prey including vegetal resources and fish unavailable to carnivores. As aboriginal hunting pressure declines prey populations increase. In fact, the authors note that the influenza epidemic of 1918 decimated native populations on Ungava, which in turn allowed Caribou to increase.

I certainly commend the authors for presenting data on aboriginal peoples since the time Ungava was first inhabited and for describing how human hunting impacts Caribou. Most other studies of ungulate ecology begin with the premise that native people are irrelevant because everything was a “wilderness” untouched by the hand of man prior to the arrival of Europeans; e.g., see The Kruger Experience. As I have explained elsewhere, however, this is a fatal error. The authors did not make that mistake but I would suggest they need to look deeper into human evolutionary ecology. Take the seemingly random movements of Caribou, a subject covered at length in this book.

Unfortunately, the authors neglected to consult Binford’s data on Inuit caribou hunters - - see Numamint Ethnoarchaeology. One of the questions Binford asked was how do caribou hunters select a direction to hunt when they have no prior knowledge of where the Caribou are? The Inuit base their decisions on what we in the West would call mysticism. By careful observation, however, Binford determined that Inuit pre-hunt behavior was simply a random number generator. That is to say, in these cases, the Inuit hunted randomly, which makes perfect ecological sense, odd though it may seem.

If the Caribou moved in a predictable pattern, they would be easy prey for aboriginal hunters, as the authors note when the Ungava herd is forced by topography to cross the George River at Indian House Lake. If the hunters hunted in a predictable pattern, the Caribou would quickly learn to avoid the hunters, and the people would starve. The solution to the Caribou’s problem is to move as randomly as possible, while the solution to the hunter’s predicament is to hunt randomly. This co-evolution occurred over thousands of years and probably is the only evolutionary stable strategy available to both Caribou and humans and then only because the caribou’s range was vast and diverse. The authors note that even when Ungava Caribou numbered only 15,000 animals, spread over an immense area, aboriginal hunting alone kept the herd from increasing. Using dog sleds, native hunters would follow caribou tracks for days, until the animals were killed or the trail lost.

The Return of Caribou to Ungava should be read by everyone with even a passing interest in northern ecology, caribou management, or predator-prey relationships. It should also be read by historians, anthropologists, and archaeologists.

Caribou Numbers in the NWT — The Outfitter’s Battle

John Andre. 2007. Caribou Numbers in the NWT — The Outfitter’s Battle (PowerPoint presentation). Shoshone Wilderness Adventures, Lac de Gras, Northwest Territories, CA.

John Andre is majority stockholder in two Canadian corporations, Qaivvik, Ltd. and Caribou Pass Outfitters, Ltd.

Full PowerPoint presentation [here] (2.44MB)

Selected excerpts:

The caribou have been hunted for tens of thousands of years by the aboriginal peoples of the north. The health of the caribou herds is sacred to them, it is part of their very being. Generation after generation followed the caribou, or waited for them to come. They understood the movements of the great herds, and the cycle of feast and famine. Now, with “modern” technology, we track caribou with satellite collars, count nematodes in their droppings, and census them using fancy terms such as linear regression analysis and coefficient of variation. It is not an easy job, counting over a million animals, scattered over tens of thousands of square miles of wilderness. This presentation is not meant to degrade, in any way, the efforts of some of the wildlife biologists that have worked hard over the last 60 years, risking their lives in an unforgiving environment, with limited budgets and manpower, to study and better understand the caribou.

The Problems Begin

In late 2005, the government split the former RWED into ENR (Environment & Natural Resources) and ITI (Industry, Tourism, and Investment.) It may or may not be a coincidence, but this is when problems with the government began.

In May of 2006, we were abruptly told that we had to stop selling caribou hunts for that year; that the caribou numbers had dropped significantly. This cost the industry three months of sales, and hundreds of thousands of dollars. The question is, if the next survey hadn’t been done yet, how did the government know for sure the herds were down? Was the outcome preconceived?

In June of 2006, the Bathurst herd was surveyed, and was down to 128,000 caribou. Minister Miltenberger, of the ENR , told the outfitting industry that they were cutting our tag quotas back to the pre-2000 level of 132 tags, for the 2007 season. At the same time, resident hunters were reduced from 5 tags to 2 tags, and bulls only. (The harvest of mature bulls has consistently been shown to have zero effect on overall ungulate population growth.) The outfitting industry, although not necessarily agreeing with their numbers or science, wanted to do their part to help the caribou, and so we accepted this slashing of our industry by nearly 30%.

The fact is, we hadn’t looked at the numbers carefully enough.

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Variation In Mitochondrial DNA and Microsatellite DNA in Caribou (Rangifer Tarandus) in North America

Matthew A. Cronin, Michael D. Macneil, and John C. Patton. 2005. Variation In Mitochondrial DNA and Microsatellite DNA in Caribou (Rangifer Tarandus) in North America. Journal of Mammalogy, 86(3):495–505, 2005.

Full text [here]

Selected excerpts:

ABSTRACT

Genetic variation of caribou (Rangifer tarandus) at 18 microsatellite DNA loci and the cytochrome-b gene of mitochondrial DNA (mtDNA) was quantified in 11 herds of 3 North American subspecies: Alaskan barren ground caribou (R. t. granti), Canadian barren ground caribou (R. t. groenlandicus), and woodland caribou (R. t. caribou). Phylogenetic analysis of 1,194 nucleotides of cytochrome-b sequence resulted in a clade of 52 genotypes in R. t. granti, R. t. groenlandicus, and in 1 herd of R. t. caribou, and a clade of 7 genotypes in R. t. caribou. mtDNA sequence divergence is approximately 1% between these clades and 0.3–0.6% within these clades. The subspecies do not have monophyletic mtDNA, but do have different frequencies of mtDNA genotypes. Microsatellite allele frequencies also are differentiated between the woodland (R. t. caribou) and barren ground (R. t. granti and R. t. groenlandicus) subspecies. An exception is the George River herd in Labrador, which is classified as R. t. caribou but has mtDNA and microsatellite allele frequencies intermediate between the other herds of R. t. caribou and R. t. groenlandicus. Within subspecies, there is relatively low differentiation of microsatellite allele frequencies and mtDNA genotypes among herds of R. t. granti and R. t. groenlandicus, and relatively high differentiation of microsatellite alleles and mtDNA genotypes among herds of R. t. caribou in 4 geographically separate areas in Canada. The extent of differentiation of mtDNA genotype frequencies and microsatellite allele frequencies within and among each subspecies reflects past and present gene flow among herds. Issues related to subspecies, populations, ecotypes, and herds are discussed.
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Effects of Wolf Predation on North Central Idaho Elk Populations

Idaho Department of Fish and Game, April 4, 2006, Effects of Wolf Predation on North Central Idaho Elk Populations

Full text [here] (2.3 MB)

EXECUTIVE SUMMARY

Gray wolves (Canis lupus) were reintroduced into Idaho in 1995 and listed as an experimental nonessential population under Section 10(j) of the Endangered Species Act (ESA). Thirty-five wolves were reintroduced and by 2005, an estimated 512 wolves (59 resident packs and 36 breeding pairs) were well distributed from the Panhandle to southeast Idaho. In February 2005, the U.S Fish and Wildlife Service (USFWS) modified the 10(j) rule which details State options for management of wolves impacting domestic livestock and wild ungulates (Endangered and Threatened Wildlife and Plants; Regulation for Nonessential Experimental Populations of the Western Distinct Population Segment of the Gray Wolf [50 CFR Part 17]).

The provisions of the 10(j) rule fall short of allowing the states’ preferred management tool of regulated hunting. However, under Section (v): “If gray wolf predation is having an unacceptable impact on wild ungulate populations (deer, elk, moose, bighorn sheep, mountain goats, antelope, or bison) as determined by the respective State and Tribe (on reservations), the State or Tribe may lethally remove wolves in question. In order for the provision to apply, the States or Tribes must prepare a science-based document that: 1) describes what data indicate that ungulate herd is below management objectives, what data indicate there are impacts by wolf predation on the ungulate population, why wolf removal is a warranted solution to help restore the ungulate herd to State or Tribal management objectives, the level and duration of wolf removal being proposed, and how ungulate population response to wolf removal will be measured; 2) identifies possible remedies or conservation measures in addition to wolf removal; and 3) provides an opportunity for peer review and public comment on their proposal prior to submitting it to the Service for written concurrence.”

This document supports the State’s determination that gray wolf predation is having an unacceptable impact on a wild ungulate population. Specifically, this document reviews the Idaho Department of Fish and Game (IDFG) evaluation of the effect of wolf predation on an elk population below state management objectives. The document includes a review of elk population data, the cause-specific mortality research being conducted on elk, the wolf population data, and the modeling conducted to simulate impacts of wolf predation on elk using known population parameters. Additionally, this report identifies remedies and conservation measures that have already been attempted to reduce impacts of the multiple factors influencing the current elk population status, and identifies management actions and objectives to improve and monitor elk populations in the Lolo Zone.

This evaluation addresses the criteria outlined under 10J SEC. (v) and provides detailed information on the following topics:

1. What is the elk management objective?

Management objectives for elk in the Lolo Zone (Game Management Units [GMU] 10 and 12) is to maintain an elk population consisting of 6,100 – 9,100 cows and 1,300 – 1,900 bulls. Individual GMU objectives for the Lolo Zone are: 4,200 – 6,200 cows and 900 – 1,300 bulls in GMU 10; and 1,900 – 2,900 cows and 400 – 600 bulls in GMU 12. Population objectives for GMU 17 are 2,400 – 3,600 cows and 650 – 975 bulls. Objectives are based on the Department’s best estimate of elk habitat carrying capacity and acknowledge a reduction in habitat potential from the conditions observed in the 1980s. In 1989, the Department estimated 16,500 elk in the Lolo Zone. Current cow and bull objectives (7,400) are 60% of the 1989 estimate of 12,378 cow and bull elk. In 2006, the Department estimated 4,233 cow and bull elk in the Lolo Zone.

2. Data used to evaluate populations in relation to management objective.

IDFG biologists use aerial surveys to monitor elk populations throughout the state, including GMUs 10, 12, and 17. Surveys are designed to provide a statistically and biologically sound sampling framework. Biologists generate estimates (and confidence intervals) of population size, age ratios (e.g., calves:100 cows) and sex ratios (e.g., bulls:100 cows) from the survey data. Current status of elk populations are: 2,276 cows and 504 bulls in GMU 10; 978 cows and 475 bulls in GMU 12; and 2,076 cows and 486 bulls in GMU 17.

3. Data that demonstrate the impact of wolf predation.

Elk survival rates were estimated using radio-collared animals. A total of 64 adult cow elk were captured, radio-collared, and monitored in GMUs 10 and 12 in 2002-2004 (90 elk-years). Combining samples across areas and years produced point estimates of annual elk survival (includes all mortality sources) ranging from 75% to 89%, with a 3-year weighted average of 83%. More recently, survival from March 2005 through February 2006 was 77%.
Nine of 25 (36%) mortalities among adult cow elk from January 2002 through March 2006 were attributed to wolves. Wolf-caused mortality was not detected during 2002 or 2003; whereas 1 death was attributed to wolf predation in 2004 and 8 through 1 March 2006. Three additional losses resulted from predation, but species of predator could not be determined; 4 were attributed to mountain lions; and 9 were attributed to factors other than predation (e.g., hit by a vehicle, harvested, disease) or cause of death could not be determined.

Similar survival and cause-specific mortality data for elk in GMU 17 does not exist because of logistical difficulties with capture and monitoring of elk in designated Wilderness.

IDFG used the available data and assumptions based on peer-reviewed literature to simulate the impacts of wolf predation on elk populations in north-central Idaho. All simulations revealed a lack of cow elk population growth in the presence of wolf predation. Most simulations suggest moderate to steep declines in abundance caused by wolf predation. Regardless of the approach we used to model elk populations, all simulations used suggest wolves are limiting population growth.

4. Why wolf removal is warranted.

Several factors may have contributed to the elk population decline in the Lolo Zone, including harvest management, habitat issues, and predation. The Department and collaborators have aggressively addressed each of these factors for a number of years. Nevertheless, the Lolo Zone does not meet state management objectives. Without an increase in cow elk survival, the Lolo Zone elk population is unlikely to achieve management objectives.
The available data indicate that wolf predation is, at a minimum, partly additive and likely contributes to low adult female elk survival. Based on our evaluation and analysis, the State has determined that wolf predation is having an unacceptable impact on elk populations in the Lolo Zone. This evaluation demonstrates that wolves play an important role in limiting recovery of this elk population and that wolf removal is warranted as allowed under the 10(j) rule.

Management of most big game populations is accomplished through regulated harvest by hunters. A reduction in wolf numbers in the Lolo Zone would ideally be accomplished through regulated take by sportsmen rather than by state or federal agencies, and all alternatives for removal would be explored.

5. Level and duration of wolf removal.

During year one, we propose to reduce the wolf population in the Lolo Zone by no more than 43 of the estimated 58 wolves (75% reduction) that currently occupy the zone. The first year reduction represents about 8% of the estimated 512 wolves present in Idaho in 2005. The wolf population will be maintained at 25-40% of the pre-removal wolf abundance for 5 years. Concurrently, we will monitor elk and wolf populations. After 5 years, results will be analyzed and a peer-reviewed manuscript will be prepared that evaluates the effect of fewer wolves on elk population dynamics.

6. How will ungulate response be measured?

We will monitor the performance of elk populations in GMUs 10 and 12 with ongoing statewide research efforts on elk and mule deer and within the context of Clearwater Region wildlife management activities. The information will include fecundity, age/sex-specific survival rates, and cause-specific mortality rates. We will use aerial surveys to monitor elk populations in GMUs 10, 12, and 17. In GMUs 10 and 12, complete surveys will be scheduled for 2006, 2008, and 2010. In GMU 17, complete surveys will be scheduled for 2007 and 2010. Composition surveys will be flown in intervening years. In GMUs 10 and 12, we will document elk survival rates and cause-specific mortality factors from samples of radio-marked adult cow and calf elk.

The Truth about Our Wildlife Managers’ Plan to Restore “Native” Ecosystems

George Dovel. 2008. The Truth about Our Wildlife Managers’ Plan to Restore “Native” Ecosystems. The Outdoorsman, Number 30, Aug-Sept 2008.

Full text [here]

Selected excerpts:

In 1935 when Cambridge University botanist Arthur Tansley invented the term “ecosystem” in a paper he authored, he was attempting to define the system that is formed from the relationship between each unique environment and all the living organisms it contains.

Ecologists concluded that these individual systems evolved naturally to produce an optimum balance of plants, herbivores that ate the plants, and carnivores that ate the herbivores. Many accepted this “food chain” theory as a permanent state of natural regulation and a theory was advanced that certain “key” species of plants and animals were largely responsible for maintaining these “healthy” ecosystems.

But subsequent archeological excavations or core samples of the buried layers of periods in time revealed that these “perfected” ecosystems were actually in a continuing state of change which could be caused by changes in weather, climate or various organisms. They concluded that parasites or other organisms that were not included in their food chain charts often caused radical population changes in one or more of the keystone species.

The “Balance-of-Nature” Myth Keeps Surfacing

In 1930 noted Wild Animal Ecologist Charles Elton wrote, “The ‘balance of nature’ does not exist and perhaps never has existed. The numbers of wild animals are constantly varying to a greater or less extent, and the variations are usually irregular in period and always irregular in amplitude (being ample).” Yet 33 years later, in a highly publicized Feb. 1963 National Geographic article, titled, “Wolves vs. Moose on Isle Royale,” fledgling Wolf Biologist David Mech and his mentor, Durward Allen, claimed just the opposite. …

Debunking the “Balance-of-Nature” Myth

The extreme “spikes” (highs and lows) in numbers of keystone species resulting from reliance on the theory that “natural regulation” will produce a “balance” are evidence that the so-called “Balance of Nature” is a pipe dream. One fairly long-term example of this is seen in the following graph recording 50 years of wolf and moose populations on Isle Royale National Park in Michigan.

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The Need for the Management of Wolves

Bergerud, Arthur T. The Need for the Management of Wolves-An Open Letter. 2007. Rangifer, Special Issue No. 17, 2007: The Eleventh North American Caribou Workshop, Jasper, Alberta, Canada, 24-27 April, 2006.

Note: A.T. Bergerud is former chief biologist of Newfoundland. He has been a population ecologist involved in research on caribou populations in North America since 1955. Along with Stuart N. Luttich and Lodewijk Camps, Bergerud authored the just released The Return of Caribou to Ungava [here].

Full text [here]

Selected excerpts:

Abstract: The Southern Mountain and Boreal Woodland Caribou are facing extinction from increased predation, predominantly wolves (Canis lupus) and coyotes (Canis latrans). These predators are increasing as moose (Alces alces) and deer (Odocoileus spp.) expand their range north with climate change. Mitigation endeavors will not be sufficient; there are too many predators. The critical habitat for caribou is the low predation risk habitat they select at calving: it is not old growth forests and climax lichens. The southern boundary of caribou in North America is not based on the presence of lichens but on reduced mammalian diversity. Caribou are just as adaptable as other cervids in their use of broadleaf seed plant as forage. Without predator management these woodland caribou will go extinct in our life time.

Introduction

A major ecological question that has been debated for 50 years is: are ecosystems structured from top-down (predator driven) or bottom-up (food limited) processes (Hairston et al., 1960; Hunter & Price, 1992)? Top-down systems can vary widely from sea mammals such as sea otters (Enhydra lutris) to ground nesting birds. The sea otter causes an elegantly documented trophic cascade through sea urchins (Strongylocentrotus spp.) down to kelp beds (Estes & Duggins, 1995). Ground nesting waterfowl and gallinaceous birds are not limited by food resources but are regulated by top-down nest predation caused by a suite of predators, mainly skunks (Mephitis mephitis), red foxes (Vulpes vulpes) and crows (Corvus brachyrhynchos) (Bergerud, 1988; 1990; Sargeant et al., 1993). Management decisions depend on understanding which structure is operational.

Discussions on top-down or bottom-up have been recently been rekindled with the introduction of wolves (Canis lupus) to Yellowstone National Park and Idaho in 1995 (Estes, 1995; Kay, 1995; 1998). The elk/wapiti (Cervus elaphus) population in Yellowstone prior to introduction were basically limited by a density-dependent shortage of food (Singer et al., 1997) but now is declining from wolf predation (Crête, 1999; White & Garrott, 2005). All three states, Wyoming, Idaho, and Montana, are litigating the federal government to get the wolf delisted so they can start wolf management to maintain their stocks of big-game.

We conducted a 30 year study (1974 to 2004) of two caribou (Rangifer tarandus) populations, one in Pukaskwa National Park (PNP) and the other on the Slate Islands in Ontario, relative to these two paradigms of top-down or bottom-up. (Bergerud et al., this conference). In Pukaskwa National Park, there was an intact predator-prey system including caribou, moose (Alces alces), wolves, bears (Ursus americanus), and lynx (Lynx canadensis). On the Slate Islands, our experimental area, there were no major predators of caribou. The PNP populated was regulated top-down by predation and existed at an extremely low density of 0.06 caribou per km2, whereas the population on the Slate Islands averaged 7-8 animals/km2 over the 30 years (100X greater than in PNP). In the absence of predators, these island caribou were regulated from the bottom-up by a shortage of summer foods and the flora was impacted, resulting in some floral extinctions. The extremely low density of only 0.06 caribou per km2 in PNP is normal for caribou populations coexisting with wolves (Bergerud, 1992a: Fig. 1, p. 1011). The top-down predator driven ecosystem of caribou in PNP also applies in Canada to moose, elk, and black-tailed deer (Odocoileus hemionus) that are in ecosystems with normal complements of wolves and bears (Bergerud, 1974; Bergerud et al., 1983; Bergerud et al., 1984; Messier & Crete, 1985; Farnell & McDonald, 1986; Seip, 1992; Messier 1994; Hatter & Janz 1994; Bergerud & Elliott, 1998; Hayes et al., 2003).

Of all the predator driven ecosystems of cervids, the threat of extinction is most eminent for the southern mountain and boreal woodland caribou ecotypes, both classified as threatened (COSEWIC 2002, Table 11). These herds are declining primarily from predation by wolves plus some mortality from bears. From west to east the equations for continued persistence are not encouraging — in British Columbia the total of the southern mountain ecotype is down from 2145 (1992-97) to 1540 caribou (2002-04) and four herds number only 3, 4, 6, and 14 individuals (Wittmer et al., 2005). In Alberta, the range has become fragmented and average recruitment recently was 17 calves/100 females, despite high pregnancy rates (McLoughlin et al., 2003). That low calf survival is less than the needed to maintain numbers - 12-15% calves or 22-25 calves per 100 females at 10-12 moths-of-age to replace the natural mortality of females (Bergerud, 1992a; Bergerud & Elliott 1998). In Saskatchewan, populations are going down, ?=0.95 (Rettie et al., 1998). The range is retreating in Ontario (Schaefer, 2003) as southern groups disappear; in Labrador the Red Wine herd is now less than 100 animals (Schmelzer et al., 2004); in southern Quebec, there may be only 3000 caribou left (Courtois et al., 2003), and in Newfoundland, herds are in rapid decline from coyotes (Canis latrans) and bear predation (G. Mercer and R. Otto, pers. comm.). In Gaspé, the problem for the endangered relic herd is also coyotes and bear predation (Crête & Desrosiers, 1995). In Gaspé, these predators have been reduced and there is a plan in place to continue adaptive management (Crête et al., 1994). Do we have to wait until the herds are listed as endangered to manage predators?