Apart from humans, wolves are the terrestrial mammals with the broadest natural distribution. The gray wolf, Canis lupus, once ranged over most of the Northern Hemisphere. However, lethal persecution and habitat loss to human development considerably reduced its range. In North America, the wolf was extirpated from most of southern Canada and Mexico and from the coterminous 48 US states, expect for northern Minnesota, by 1970. Today large populations can be found only in northern Canada and Alaska.
In Canada and the United States, attitudes toward gray wolves have changed drastically in recent years. Now preservationist groups and large sectors of the public regard the wolf positively, viewing its preservation as a high priority for wildlife conservation efforts .... In the United States, owing to natural recolonization and reintroduction programs, wolves are recovering in the northern, northwestern and southwestern states. Thus, wolves are returning to areas that support human...activities such as ranching and farming, which may be incompatible with wild wolf populations. Depending on circumstances that are highly context specific, people often resort to apparently contradictory management strategies that include hunting, control, reintroduction, and protection of wolves. The degree of application of these strategies in different areas and at different times determines alternative scenarios and outcomes for wolf populations. A current challenge is to make local inputs consistent and to monitor their effects on a broad scale.
Herein, we review information on interactions between humans and wolves by means of focusing on human attitudes and their effects on wolf management. We analyze in detail the problems and opportunities for wolf conservation in modern North America .... Finally, we draw on our direct experience with wolf conservation as an important, yet controversial, example of the approach chosen in North America to address the conflicts between wildlife requirements and human interests.
Foundations for historical and current killing of wolves
In North America, people have killed wolves for fur, for protection of livestock and wild ungulates, for disease control, and out of fear .... [S]ome authors believe aboriginal peoples killed wolves to enhance ungulate populations and claim that wolf hunting was more intense when ungulate numbers were perceived to be low. Some ecologists believe wolf predation is a major limitation to the growth of wild ungulate populations, second only to human influences.
Jedrejewski and colleagues (2000) addressed this issue in Poland, where red deer (Cervus elaphus) was the major source for wolves....Results...indicated that predation by wolves probably contributed to the population dynamics of red deer, but hunting by humans influenced the phenomenon to a greater extent. This project provides an example of the difficulties encountered by wolf ecologists in evaluating predator-prey dynamics. Most ecosystems include a variety of prey and predator species as well as humans; the latter exert impacts on the ecosystem indirectly (e.g., through development) and directly (e.g., through hunting or protection of certain species. In addition, plant availability varies seasonally and yearly, and humans can exert impacts on plants through agriculture and forestry practices. Thus, plants, herbivores, predators, and humans often participate in complex food webs. As a result, it can be arduous to sort out the effects of predator densities on prey abundance.
....[A]griculture is a major source of wolf-human conflict. Wolf depredation on domestic animals that were introduced by Europeans to the United States and southern Canada prompted control programs to eradicate wolves. In the 17th century, government agencies began to pay bounties for wolves killed by private individuals. Until recently, bounty programs had been established, suspended, and reinstated in various North American jurisdictions. Wolves have been poisoned, trapped, snared, and shot from the ground and air. The most successful strategy used to exterminate wolves has probably been the poisoning campaigns that involved personnel hired by government agencies.
During modern history and until the 1970s, wolves were hunted without restrictions, and their pelts were sold at auction markets or kept for local use. At present, wolves are killed for recreational and commercial purposes in Alaska and in most Canadian provinces and territories. In general, government authorities regulate wolf hunting and trapping by specifying the number of wolves to be killed, the length of the season, and the hunting and trapping techniques allowed. However, in Canada, aboriginal people are not subject to wolf hunting quotas. This lack of restrictions in considered an "aboriginal right" affirmed under the Canadian constitution. Some hunters from northern Canada claim annual incomes of more than CDN$50,000 from selling wolf furs. Thus, large numbers of wolves are hunted, providing an important source of revenue for many communities in Alaska and northern Canada.
Unlike wolf populations in southern Canada and the contiguous United States, which have been reduced or extirpated, those in Alaska and northern Canada remain widely distributed and abundant. In Canada, the wolf is not listed by the Committee on the Status of Endangered Wildlife in Canada .... [S]ome biologists are concerned about the killing of wolves in certain areas of northern Canada. They consider such commercial hunts a problem because of the vulnerability of individual wolves to the specific hunting techniques employed, particularly the use of snowmobiles .... Hunters can use snowmobiles to quickly approach escaping wolves until they are within range of a rifle.
Current wolf killing
The idea that wolves can affect the mortality rates and conceivably the actual densities of their prey has provided the basis for researchers' and managers' attempts to diminish wolf densities and thus obtain increases in wolf ungulate numbers. During wolf control, Alaskan and Canadian managers could reduce wolf numbers by up to 80% of the winter population. Their stated objective has been to protect populations of wild ungulate numbers. Wolf control programs have been demonstrated to increase ungulate numbers, but because of negative public reaction, such programs have been delivered at substantial costs to the agencies involved .... In certain areas, government agencies have resorted to fertility control of wolves in an attempt to keep wolf numbers low without culling.
Some government agencies cull wolves to reduce conflicts between wolves and livestock. Wolf control is applied for this reason in Minnesota and in several Canadian jurisdictions. In addition, the experimental rules governing the reintroduction of wolves to central Idaho, the greater Yellowstone area, and Arizona allowed for killing of wolves that are suspected to prey chronically on livestock .... Differences in management among two Canadian provinces and one US state -- Alberta, British Columbia, and Montana -- sometimes affects wolves that move or disperse between these neighboring jurisdictions. Similar circumstances are likely to prevail along other portions of the US-Canadian border where wolves are present.
In some US states, private landowners are authorized to kill wolves in cases of demonstrable threats by wolves toward humans and human property, including livestock. For example, in Montana, ranchers may kill wolves if they catch them in the act of killing livestock .... [I]n Alberta, landowners and their delegates may kill wolves without restriction on their property and within 8 kilometers of their land. Landowners whose properties are threatened by wolves may also be issued a special permit to poison wolves. In North America, illegal use of poison to kill wolves has also been reported in several areas, particularly where wolf populations overlap with agriculture. Recently, the conservationist organization Defenders of Wildlife and the US Fish and Wildlife Service (USFWS) offered a $20,000 reward for information leading to the arrest and conviction of those responsible for illegally poisoning gray wolves in central Idaho. Mech (1995) maintains that if some wolf killings by locals is not allowed, more wolves could be killed in the end because of resentment toward the wolves and the government.
Public sensitivity to the killing of predators has made any killing of wolves a contentious issues .... Such controversy has the potential to exacerbate already entrenched and inflexible positions in the confrontation between wolf preservationists and antiwolf advocates. Such conditions promote discrepancies in human attitudes and may lead to inconsistencies in management of wolves.
The negative contribution of wolf habitat loss and roads
The indirect effects of human land use may intensify impacts on wolf populations through habitat loss. Corsi and colleagues (1999) and Mladenoff and colleagues (1999) used geographic information systems and wolf occurrence data to assess the importance of landscape-scale factors in determining favorable wolf habitat. These analyses agree as to the importance of an adequate prey base, the existence of protected areas and public lands, and the absence or low occurrence of livestock. Wolves thrive in areas with high ungulate densities but tend toward local extinction in areas with high densities of livestock, owing to conflicts with ranchers. Positive relationships have also been found between wolf presence and areas with forest cover, few roads, and low human density. However, some sources maintain that such areas are simply the least accessible to humans, and the lack of human presence remains the most important variable in predicting wolf viability. Depending on the intensity of logging and on the tree species targeted, forestry operations can favor or hamper ungulate species that also constitute wolf food, thereby influencing wolf predation and wolf density.
In areas where public access is restricted, road density is a poor indicator of wolf presence, which suggests that wolves may avoid people rather than roads. Wolf absence from roaded areas may be a direct result of higher mortality there. Roads and other linear developments provide people access to remote regions, allowing humans to deliberately, accidentally, or incidentally kill wolves. Finally, in mountain terrain, both people and wolves must use valley bottoms where roads converge with high-quality habitat; thus, avoidance of humans and habitat selection by wolves may conflict. Moreover, protected areas are often located at higher elevations and in habitats not selected by wolves.
In general, habitat assessment for developed countries conclude that favorable habitat is highly fragmented. Thus, the future of the wolf in human-dominated areas is likely to depend on understanding and implementing a connected network of core areas where the wolf will be managed in ways appropriate to local ecological, social, and economic conditions. This approach also focuses on the availability of good habitat in the matrix outside the few existing protected areas.
Impacts of wolf reductions versus wolf resilience: Two approaches
Inherent biological characteristics render the wolf capable of rapid increases in population numbers following reduction caused by humans. Depending on the age and sex structure of the pack, wolves can sustain an annual mortality of about 30% of the winter population. After lethal control efforts that reduced populations by as much as 80%, wolf populations in the Yukon rebounded in 4 to 5 years. The most important factor influencing the rate of recovery, however, was immigration from neighboring areas.
....Haber (1996) questioned whether the measure of successful wolf conservation should be the presence of wolves on the landscape alone, or whether it should also include the presence of intact social relations. On the basis of a literature review, Haber concluded that humans could affect wolf ecology by influencing the behavior of wolves and their prey. Paradoxically, other researchers (e.g.,Ballard et al. 1987, Hayes and Harestad 2000) viewed the same literature as evidence of resilience and reported that in comparison with unexploited populations, mortality rates are higher as a direct consequence of reductions, pack sizes are smaller, home ranges are less stable and occupied at variable times, and more young are produced in the population.
....Mech (1995, 1998) maintains that to have wolves coexist with people, some form of wolf control is necessary. The alternative is that wolves at high densities may not survive conflicts with humans. Instead, if most of the public could accept both wolf recovery and wolf control in human-developed areas, then stability could be achieved between the requirements of humans and those of wolves....
Human perceptions of wolves
Some North American aboriginal clans were named after the wolf, attesting to their high respect for these animals. More recently, the North American public has demonstrated a remarkable interest in wolves....In several regions, however, the wolf has not been viewed favorably. Where reintroductions have been proposed and where wolves are recovering, some people have feared that wolves would cause livestock losses and declines of ungulate populations....
Contentious and conflicting feelings about wolves were confirmed by Kellert and colleagues (1996) in a survey of human attitudes throughout North America. Most individuals perceived wolves positively, whereas a minority feared wolves. Most wolf-related fears were linked to misperceptions and not to biological characteristics of the animal. To address these erroneous beliefs, some authors recommend education programs. Accordingly, a common ethos regarding wolves and related management issues could be constructed....
Evidence that targeted education programs actually result in accomplishments for wolf conservation is limited or speculative. Surveys ... demonstrated that higher levels of education were correlated with positive attitudes toward wolves. Thus, wolf-specific education programs might also contribute to enhancing positive attitudes and result in higher tolerance for wolves in the landscape....
Wolf protection in areas with little human use
....According to Forbes and Theberge (1996), the movements of wolves in and out of Algonquin Park, Canada (7726 km2, an area bigger than the state of Delaware) exemplify management issues regarding the spatial requirements of large predators and the inadequate size of protected areas. Their study demonstrated that for radio-monitored wolves captured in the protected area, the major cause of death was human-related. Most wolves died outside the protected area. This was also related to seasonal movements by wolves out of the park in response to migrating deer. In the mid-1990s, under the pressure of various environmental groups, the government banned the killing of wolves in a 200-km2 deer wintering area next to the park for a period of 30 months. This led to animosity toward wolves by local communities, which also included ranchers. During the period of the ban, locals killed wolves in areas outside the park. Thus, environmentalists and some of the researchers asked for a 10-km "exclusion" zone all around Algonquin Park as a buffer to protect wolves. Theberge and Theberge (1998) concluded that complete protection of wolves requires protection beyond the existing boundaries of Algonquin Park.
However, in some cases, wolves have proved capable of recovery despite the absence of protected areas such as provincial and national parks. Up to 1995, when wolves were reintroduced in Yellowstone and Central Idaho, documented increases in wolf numbers for the coterminous 48 US states were largely due to recovery in the Great Lakes region. Haight and colleagues (1998) analyzed wolf population survival with a computer simulation, which assumed that wolf packs occupy home ranges with secure core areas, that higher human-caused mortality occurs in peripheral areas, and that prey is available....Their results showed that the availability of core areas characterized by low human-caused mortality was an important predictor for the presence of wolves. Nonetheless, wolf survival also depended on natural mortality. Thus, disease-free and legally protected populations could thrive with just a few core areas available. Finally, even limited immigration of wolves could offset higher levels of mortality. Simulations by Haight and colleagues (1998) show that wolves can survive in developed regions if home ranges are allowed to form a network in which each range in reachable by wolves dispersing from other ranges....
Wolves are highly mobile animals that will encounter people during their wanderings in most areas of North America in which the species occurs....Despite the conflicts between wolves and people out of protected areas, wolf conservation status is improving, and wolf numbers are increasing or stable in most North American areas where livestock production is not a priority. Thus, we conclude that coexistence of people and wolves is possible in wild or semiwild areas.
Ongoing conflicts with people and livestock
Wolves typically prey on all ungulates present within their range. Often included are domestic ungulates....[A]s the result of wolf recovery, wolves are moving into areas of intense livestock production. In these areas, conflicts and associated costs of livestock protection are on the increase. For example, Mech (1998) estimated the monetary costs of maintaining wolves in American wild and agricultural areas and concluded that wolves frequenting agricultural areas cost twice as much to manage as wolves living primarily in the wilderness.
In Eurasia, where livestock has historically coexisted with the wolf, traditional husbandry techniques involve shepherds tending small flocks of livestock and using guard dogs. Such husbandry techniques, however, are not economical and are difficult to apply where a guard dog culture is not established. In regions where traditional experience is lacking, dogs are often left without the essential aid of ranchers or shepherds, who typically provide additional guidance and surveillance. In these situations, depredation by wolves and other predators can occur despite the presence of guard dogs. In addition, wolves can kill dogs, further exacerbating negative attitudes toward wolves.
In areas where guard dogs are not used, typical methods for reducing depredation on livestock include culling and employment of barriers or electric fences to exclude wolves. However, culling is inherently controversial and conventional fences are expensive and difficult to maintain. Other methods used include the translocation of wolves from areas of high livestock production to wilder areas and the aversive conditioning of wolves to livestock. Unfortunately, these methods are expensive and provide only temporary relief from depredation.
Research is needed to evaluate the use of nonlethal, cost-effective means to protect human interests from wolves (and consequently wolves from humans) in areas where conflicts exist. Ironically, an ancient wolf-hunting technique may offer a cost-effective solution. This technique, known as fladry, was used to hunt wolves in Eastern Europe and Russia. Fladry consists of driving wolves into a bottleneck formed by 50-centimeter (cm) x 10-cm red flags hanging from ropes stretched above the ground. Musiani and Visalberghi (2001) conducted experiments that demonstrated fladry's effectiveness in excluding captive wolves from food and confining wolves in limited spaces. The fladry technique has potential for the management of wolf-livestock conflicts; we are conducting additional field studies to evaluate its effectiveness for protecting livestock.
Compensation for livestock losses
Compensation programs are a major means to refund the economic damage to livestock producers created by wolves and thus to reduce conflicts. In spite of this, compensation may not be socially or economically sustainable over the long term. Costs may increase because preventive husbandry practices are abandoned, and communities may refuse to bear the increased costs. For these reasons, some authors suggest that compensation programs should be designed in combination with incentives to encourage preventive management.
A real-world example of depredation management is offered by Sweden. Before 1996, the compensation program was run in a standard fashion. Affected livestock producers were required to contact authorities, fill out a compensation request form, and undergo an investigation by government authorities. Since 1998, in the northern regions of Sweden where reindeer production is a major economic activity, the compensation funds are allocated to communities. The only prerequisite is that such communities should demonstrate that predators of livestock frequent the area. In southern Sweden, where sheep production is predominant, the government disseminates some funds, which are to be used for damage prevention measures, to local communities. In this region, compensation of actual livestock losses is paid only if prevention measures are not in place. These multifaceted policies are proving successful and may be facilitating the successful recovery of the wolf population in Sweden.
Compensation programs exist in most US jurisdictions and in some Canadian provinces where wolves and livestock are present. Typically, arrays of provincial, state, federal, and private funds provide financial compensation ranging from 85% to 100% of the estimated market value for confirmed kills. Canadian provincial officers or USFWS personnel conduct inspections at depredation sites. Veterinary costs for the treatment of injuries caused by wolves are also often refunded. A confounding factor for compensation programs is that carcasses may not be found or may be found after decomposition and scavenging preclude an assessment of the cause of death. This may result in undercompensating the actual damage caused by wolves. In addition, in some areas (for example, the Canadian province of Alberta), losses of less common livestock species, such as horse, llama and alpaca, are not refunded. Moreover, those ranchers who spend time and incur expenses trying to reduce the chance of depredation are often not compensated. Nor do programs account for reproductive status (i.e., pregnancy), and only the meat value on a per-pound market basis is compensated....
Current trends for wolf conservation in North America
In the conterminous US states, the federal Endangered Species Act (ESA) has protected all wolves since 1974. The ESA is the strongest species protection legislation in the United States, usually superseding state laws. In 1978, Minnesota wolves were delisted by USFWS from endangered to threatened (43 Federal Register 9612, 9 March 1978). This delisting allowed depredating wolves to be killed by authorities. Following recent recovery in the United States, on 1 April 2003 USFWS implemented federal reclassification of wolf populations under the ESA (Federal Register 68 : 15803-15875 [to be codified at 50 CFR Part 17]). The most significant change was delisting the endangered populations to threatened status in the coterminous US states, except for the Yellowstone area, central Idaho, Arizona, and New Mexico. In these areas, wolves retain their "experimental nonessential" designation and will continue to be subject to different regulations. In addition, wolves in the southwestern United States (including Arizona and New Mexico) will retain their endangered status. Finally, wolves are removed from ESA protection in the regions where the species historically did not occur....[A] stated objective of the reclassification project has been to increase the ability to respond to wolf-human and wolf-livestock conflicts through lethal control.
....Populations that are considered viable will be managed by individual states. However, wolf management will have to be integrated among states belonging to three distinct population segments (DPSs): the western DPS, the eastern DPS, and the southwestern DPS. In addition, the federal government will be required to monitor the wolf populations within such DPSs. If the monitoring shows that the populations are in jeopardy, the federal government can relist the wolf. Individual states are preparing to manage wolves after delisting; new state legislation may include culling of wolves that depredate on livestock.
Regardless of government regulation, human attitudes will play a pivotal role in the persistence of wolf populations. In Canada and the United States...attitudes tend to be positive and are related to attitudes about other carnivores and environmental issues. However, opposition by local communities to wolf presence (especially in agricultural areas) may indicate social and economical pressures that are not compatible with successful wolf and wilderness conservation. Despite the biological resilience of wolves, which often allows them to survive persecution, humans have proved capable of quickly eradicating wolves from agricultural and developed areas.
Management strategies regarding wolves in North America range from full protection to hunting and control....This may result in inconsistent management practices across time, jurisdictions, and environments. These inconsistencies are determined largely by real or perceived conflicts between the interests of wolves and people. Among such conflicts, a predominant role is played by the still-unresolved problem of wolf depredation on livestock. Therefore, conservation efforts should focus disproportionately on rural areas, where human-wolf conflicts are more likely to occur....
....As wolves keep moving into rural areas where livestock production is a major economic activity, managers, ranchers, and farmers may choose to diminish the occurrence of conflicts by proactively protecting livestock from wolves with lethal or nonlethal methods. There is a long history of lethal interventions by the livestock industry to protect stock from wolf depredation. However, today many North Americans prefer nonlethal methods, which are not yet in common use. If proved to be cost-effective and efficient, nonlethal methods could become more accepted by livestock producers and have the potential to improve wolf conservation....
If cost-effectiveness and successful wolf conservation are desired, then compensation programs should be readily available to livestock producers. Compensation should be designed to refund all real-world costs of wolf depredation, including costs of actual losses that are undetected but can be estimated and, more important, all costs associated with the deployment of prevention measures. Nonlethal techniques tend to be costly and are effective only under some conditions. However, changing public attitudes in support of wolf conservation necessitate that managers better understand the application of nonlethal alternatives....
In North America, the rural agricultural areas where wolves occur are often frequented by wild and domestic ungulates, both of which the wolves prey upon. Managing for high densities of wild ungulates could result in decreased livestock depredation by wolves. Some findings from southern Europe suggest that wolves prey more on wild ungulates in areas where these ungulates are at higher densities than livestock. Similar mechanisms regarding wolf predation on livestock and wild ungulates were proposed for North America. Further research is needed to test selection of wild and domestic ungulates by wolves and the factors that influence prey switching. Spatial models based on such research may be useful for predicting wolf depredation intensity and could be combined with economic impact assessments for evaluating alternatives.
Table 1: Numbers of gray wolves, and management actions for them, in North American jurisdictions where wolves are established.
Figure 1: (a) Worldwide distribution of the gray wolf. (b) Historical (pre-European) and current distribution of gray wolves in North America.
Figure 2: Wolves censused in the conterminous United States.