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.

Full text:

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

Full text:

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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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).

Full text:

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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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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Yellowstone’s Destabilized Effects, Science, and Policy Conflict

Frederick H. Wagner. 2006. Yellowstone’s Destabilized Effects, Science, and Policy Conflict. Oxford, United Kingdom: Oxford University Press.

Review by Cliff White, Parks Canada, Banff, Alberta, Ca. [first published in Mountain Research and Development Vol 28 No 2 May 2008]

In an influential book of the 1960s, Fire and Water: Scientific Heresy in the Forest Service, Ashley Schiff (1962) documented how, for over 3 decades, the United States Forest Service subverted ecological science to justify an agency policy of total fire suppression. This policy was especially flawed in southeastern pine forests that evolved under a regime of periodic burning. Schiff’s exposé showed how, in a technologically-based society, science could be systematically manipulated to become clever advocacy for a political end. The book became a must read for a generation of ecological researchers and natural resource policy specialists.

Fred Wagner, formerly associate dean of the Natural Resources department at Utah State University, continues this tradition of exceptional scholarship to describe policy-driven research in Yellowstone, the United States’ flagship national park. Ironically, the general political and ecological scenario is in many respects similar to the southeastern pine forest debacle—management actions driven by a strong political constituency were imposed on an ecosystem ill-adapted to them, and scientists were unwilling or unable to evaluate and document obviously negative outcomes. In Schiff’s example, the fire suppression program was rooted in a strong American land management and resource husbandry movement of the early 1900s. In Wagner’s work, Yellowstone’s management and scientific research is motivated by equally powerful, but opposite societal forces supporting wilderness or “natural regulation.”

For those unfamiliar with the Yellowstone situation, removal of native peoples from the park in the 1800s and reduction in large carnivores in the early 1900s provided favorable conditions for the population of elk (Cervus elaphus), a generalist herbivore, to increase dramatically. After government biologists observed the effects of high densities of elk on soil and vegetation in the 1920s, park rangers routinely culled the herd for over 4 decades. In the 1960s, recreational game hunters lobbied to take over the cull. Given the potential political incompatibility of sport hunting with conservation in one of the world’s premier national parks, the federal government made the decision to cease elk culling. Park managers and senior scientists then carefully selected a generation of researchers to evaluate the revised policy. The result was a new paradigm of “natural regulation” that was underlain by 4 key hypotheses:

1) long-term human hunting, gathering and burning had not substantially influenced the ecosystems of North America’s Rocky Mountains;

2) ungulate populations in Yellowstone were, over the long term, generally high;

3) carnivore predation was a “non-essential adjunct” having minimal influence on elk numbers; and

4) high elk numbers would not cause major changes in plant communities, ungulate guilds, and other long-term ecosystem states and processes.

Although the natural regulation paradigm seems rather farfetched today, remember that it was born in the 1960s, a time of antiestablishment flower children, when wilderness was untrammeled by Native Americans, when biologist and author Farley Mowat’s wolves subsisted on mice (Mowat 1963), and the only “good fires” were caused by lightning. Moreover, an excellent argument can be made that ecological science needs large “control ecosystems” with minimal
human influences.

In the 40 or so years since the implementation of the national regulation policy, both the National Park Service and outside institutions conducted many ecological studies. These culminated in 1997 with a congressionally mandated review by the National Research Council. It is this wealth of research and documentation that Fred Wagner uses to evaluate changes over time in the Yellowstone ecosystem. He provides meticulous summaries of research in chapters on each of several different vegetation communities, the ungulate guild, riparian systems, soil erosion dynamics, bioenergetics, biogeochemistry and syntheses for the “weight of evidence” on the primary drivers of ecological change. This background allows readers to develop their own understanding on the results of this textbook case of applied ecological science.

Wagner clearly shows that most studies did not support the hypotheses of natural regulation. In cases where studies did seem to support a hypothesis, methods and results were suspect. The elk population clearly grew beyond predictions, some plants and animals began to disappear, and the importance of Yellowstone’s lost predators and Native Americans should have become undeniable. However, faced with these incongruities, park managers still supported the natural regulation policy. Some researchers closely affiliated with management then began to invoke climate change as a potential factor for observed ecosystem degradation, but the evidence for this was similarly tenuous. On the basis of the almost overwhelming evidence, Wagner concludes that much of the park-sponsored science on the natural regulation paradigm “missed the mark” and that “Yellowstone has been badly served by science.”

For scientists or managers working in similar arenas of high ecosystem values and intense politics, the book’s concluding chapters will be of most interest. Here, Wagner explores the interface between science and policy. As an alternate model to Yellowstone’s research and management system, he promotes an adaptive management process (Walters 1986) where an open political environment exists between scientists, stakeholders, and managers. Here, a controversial management option such as natural regulation could have been evaluated, as Wagner advises, “in the bright light of objective scientific understanding.” Stakeholders and managers could then use this knowledge as a basis to adjust policies quickly before grave ecological consequences occur.

However, the limited and, in terms of literature review, dated discussion of the public policy process is a weakness of the book. A more complete discussion of ecosystem management in a highly polarized political environment could have described a range of current approaches for collaborative problem solving. In fact, another recent review of wildlife management in Yellowstone concluded that the major problem facing the park was not the quantity or quality of the science, but the lack of mechanism to resolve conflicts between and within groups of scientists, stakeholders and agency managers. Gates et al (2005) remark that “collaboration is necessary to define what is acceptable; science is necessary to define what is possible; organizing people to use knowledge to design and implement management in the face of uncertainty is fundamental.” Applied ecological researchers, progressive managers, and stakeholders with a strong civic responsibility should strive for this ideal. Our parks, and indeed most places on our planet, need high-profile models such as Yellowstone, where science should help people to understand, value, and maintain the biodiversity of ecosystems.

REFERENCES

Gates CC, Stelfox B, Muhley T, Chowns T, Hudson RJ. 2005. The Ecology of Bison Movements and Distribution in and beyond Yellowstone National Park. Calgary, Canada: Faculty of Environmental Design, University of Calgary.

Mowat F. 1963. Never Cry Wolf. Toronto, Canada: McClelland and Stewart.

Schiff AL. 1962. Fire and Water: Scientific Heresy in the Forest Service. Cambridge, MA: Harvard University Press.

Walters C. 1986. Adaptive Management of Renewable Resources. New York: Macmillan.

Idaho Wildlife Services Wolf Activity Report

USDA-APHIS Idaho Wildlife Services Wolf Activity Report Fiscal Year 2007

Full text [here]

Selected excerpts:

Introduction

This report summarizes Idaho Wildlife Services’ (WS) responses to reported gray wolf depredations and other wolf-related activities conducted during Fiscal Year (FY) 2007 pursuant to Permit No. TE-081376-12, issued by the U.S. Fish and Wildlife Service (FWS) June 16, 2006. This permit allows WS to implement control actions for wolves suspected to be involved in livestock depredations and to capture non-depredating wolves for collaring and re-collaring with radio transmitters as part of ongoing wolf monitoring and management efforts.

Investigations Summary

WS conducted 133 depredation investigations related to wolf complaints in FY 2007 (as compared to 104 in 2006, an increase of almost 27%). Of those 133 investigations, 88 (~66%) involved confirmed depredations, 19 (~14%) involved probable depredations, 20 (~15%) were possible/unknown wolf depredations and 6 (~5%) of the complaints were due to causes other than wolves.
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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?

Wilderness and Political Ecology: Aboriginal Influences and the Original State of Nature

Kay, Charles E., and Randy T. Simmons, eds. Wilderness and Political Ecology: Aboriginal Influences and the Original State of Nature. 2002. University of Utah Press

Selected Excepts:

Preface — CHARLES E. KAY AND RANDY T. SIMMONS

Most environmental laws and regulations, such as the Wilderness Act, the Park Service Organic Act, and the Endangered Species Act, assume a certain fundamental state of nature, as does all environmental philosophy, at least in the United States (Keller and Turek 1998, Krech 1999; Spence 1999; Burnham zooo). Included in these core beliefs is the view that the Americas were a wilderness untouched by the hand of man until discovered by Columbus and that this wilderness teemed with untold numbers of bison (Bison bison), passenger pigeons (Ectopistes migratorius), and other wildlife, until despoiled by Europeans. In this caricature of the pristine state of the Americas, native people are seldom mentioned (Sluyter 2001), or if they are, it is usually assumed that they were either poor, primitive, starving savages, who were too few in number to have had any significant impact on the natural state of American ecosystems (Forman 2001), or that they were “ecologically noble savages” and original conservationists, who were too wise to defile their idyllic “Garden of Eden” (Krech 1999). As Park Service biologist Thomas Birkedal (1993:228) noted, “The role of prehistoric humans in the history of park ecosystems is rarely factored into … the equation. If acknowledged at all, [the] former inhabitants are … relegated to what one cultural anthropologist … calls the ‘Native Americans as squirrels’ niche: they are perhaps curious critters, but of little consequence in the serious scheme of nature.”

This view of native people, and the “natural” state of pre-European America, though, is not scientifically correct. Moreover, we suggest that it is also racist (Sluyter 2001). In fact, as Bowden (1992), Pratt (1992), and others have documented, the original concept of America as wilderness was invented, in part, by our forefathers to justify the theft of aboriginal lands and the genocide that befell America’s original owners. Even those who view native people as conservationists are guilty of what historian Richard White (1995:175) describes as “an act of immense condensation. For in a modern world defined by change, whites are portrayed as the only beings who make a difference. [Environmentalists may be] … pious toward Indian peoples, but [they] don’t take them seriously [for they] don’t credit [native people] with the capacity to make changes.”

Contrary to this prevailing paradigm, the following chapters demonstrate that native people were originally more numerous than once thought, that native people were generally not conservationists-as conservation is not an evolutionary stable strategy unless the resource is economical to defend, and that native people in no way, shape, or form were preservationists, as that term applies today (Berkes 1999:91; Smith and Wishnie 2000; Sluyter 2001). Instead, native people took an active part in managing their environment. Moreover, changes wrought by native people were so pervasive that their anthropogenic, managed environment was thought to be the “natural” state of the American ecosystem (Buckner 2000). In short, the Americas, as first seen by Europeans, had not been created by God, but instead those landscapes had largely been crafted by native peoples (Hallam 1975) …

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