Wildlife Management: Ontario’s Mammalian Predators
Historically, the management of large carnivores across North America has focused narrowly on exploiting their economic value and/or limiting their predation on domestic animal stocks. Ever since governments began actively managing wildlife populations in the 18th century, only minimal consideration has been given to the ecological role and inter-species interactions of wildlife. Furthermore, the manner in which many species of large carnivores – wolves, cougars, coyotes, bears, etc. – are still managed today reflects how society has traditionally perceived and interacted with the natural environment.
Many species of wildlife have typically been viewed as resources to be harvested for commercial value or as game to be hunted for sport. To this end, government policies and practices routinely have treated large carnivores as vermin to be eradicated or as obstacles to other management goals, such as increasing deer and moose numbers. This approach to wildlife management has too often resulted in the regional extermination of top carnivores across North America, including in Ontario.
In recent decades, however, there has been a substantial shift in attitude and understanding within the scientific community and the public at large. Large carnivores are now considered vital components of the ecosystem and instruments for managing and conserving the natural world. Yet, it is often unclear whether government policies have fully adopted this more enlightened ecological approach to wildlife management
Mammalian predators as ecosystem regulators and buffers
Mammalian predators exert a strong influence on their prey populations. In addition, few species fill the ecological role of top predator. As a result, the removal of top predators from a food chain can result in the overgrazing and overpopulation of habitats by their former prey, fluctuations in prey populations, and trophic cascades with far-reaching ecological consequences. For example, the virtual absence of wolves, cougars and bears in southern Ontario led MNR to establish an annual deer cull to control deer numbers in several provincial parks.
Conversely, the presence of top predators can buffer ecosystem stresses, including those that result from climate change. International experts affirm that protecting habitats, populations of species, and genetic diversity is necessary for both natural resilience and adaptation in the face of climate change. Therefore, an informed approach to the management of mammalian predators is imperative.
Mammalian predators as indicators of biodiversity
Large mammalian predators, such as wolves and bears, typically exhibit low population densities and large home ranges. Along with their position at the top of the food chain, these characteristics can make large carnivores potentially useful indicators of ecosystem health; where top predators structure ecosystems, designing conservation plans that strongly consider their needs – adequate space and habitat – can result in the conservation of a whole range of species and the ecosystems they inhabit.
Even when top predators exert a less dominant influence on lower trophic levels, they can still act as valuable indicator species for wildlife managers, a result of their low population densities and large home ranges. Unfortunately, because of these same biological characteristics, once large carnivores become extinct locally it can be difficult to re-establish and rebuild predator populations to previous levels.
The importance of qualitative biological characteristics
Even when mammalian predators have little discernible effect on the population densities of lower trophic levels, they can still shape the behaviour, distribution, habitat use, ecology and evolution of their prey. These indirect effects can trickle down to habitat users other than the predator’s prey, such that mammalian predators may exert subtle but critical effects on biodiversity in general. For example, the reintroduction of wolves into Yellowstone National Park in the United States has resulted in widespread ecological changes that affect prey species, other mammalian predators, and even vegetation patterns.
The sometimes subtle differences between the ecological roles of different mammalian predator species mean that the replacement of one by another may not necessarily result in similar impacts. For example, although the human-caused extirpation of wolf populations in southern Ontario over the last two centuries has resulted in an influx of coyotes, coyotes have not replaced wolves as a major predator of deer.
Likewise, hunting by humans cannot replace natural predation in an ecologically functional way. While humans typically hunt large, healthy ‘trophy’ animals, natural predation tends to cull the very young, old and sick from a prey population. The potential ecological significance of large carnivores warrants questioning the historical practice of harvesting these species at sustainable yield levels. True sustained-yield management should consider both the quantitative (e.g. population levels, age and sex distribution, etc.) and qualitative (e.g., sociality, territoriality, hunting behaviour, etc.) features of populations of large carnivores. This is necessary to determine whether any level of hunting or trapping is ecologically appropriate and, if so, to determine the harvest levels that would still maintain the underlying functional integrity of ecological systems.
Historical wildlife management practices in North America typically have not dealt with the qualitative features of species. Instead, management has been geared toward what has been referred to as the “farming” of wildlife – maintaining a sufficient supply to hunt or trap for recreational or commercial purposes. Indeed, this approach manages mammalian predators as if they were ungulates, which have evolved to withstand predation. In contrast, the only predator of many large carnivores is humans.
Given the potential ecological importance and vulnerability of mammalian predators, it is particularly important that their role, behaviour and ecology be well understood. It is also important that reliable information on population sizes, trends and distributions be collected. Available evidence indicates that a precautionary approach should be intrinsic in the management and conservation of mammalian predators.
The ECO reviewed MNR’s data and policies to examine whether any of the emerging knowledge of the ecology of mammalian predators has been incorporated into their management regime. Although some of the species considered in this section are not large animals (e.g., martens) or strictly carnivores (e.g., black bears), the MNR policies related to them were reviewed because many of the same management issues apply. We highlight four species here to illustrate some of these issues.
|Species||Population Estimate by MNR||Reliability of Estimate||Designation by MNR||Primary Utilization(s)||Recent Peak Annual Hunting and Trapping Levels (Approx.)|
|Eastern wolf||1,500 - 2,500||good||Regulated species at risk (special concern); Harvested as a furbearing mammal||Commercially trapped & recreationally hunted||750|
|Gray wolf||5,200 – 6,200||good||Harvested as a furbearing mammal||Commercially trapped & recreationally
|Coyote||unknown, but “abundant”||poor||Harvested as a furbearing mammal||Hunted & trapped as vermin||4,600|
|Cougar||unknown||poor||Regulated species at risk (endangered)||n.a.||n.a.|
|Bobcat||unknown||poor||Harvested as a furbearing mammal||Commercially trapped||80|
|Lynx||unknown (80,000?)||poor||Harvested as a furbearing mammal||Commercially trapped||1,800|
|Black bear||75,000-100,000||fair||Harvested as a game mammal||Recreationally hunted||6,200|
|Polar bear||1000||good||Regulated species at risk (special concern)||Limited aboriginal hunt||3|
|Fisher||unknown (40,000?)||poor||Harvested as a furbearing mammal||Commercially trapped||8,500|
|Marten||100,000-300,000||poor||Harvested as a furbearing mammal||Commercially trapped||63,000|
|Badger||100-200||good||Regulated species at risk (endangered)||n.a.||n.a.|
|Wolverine||300||good||Regulated species at risk (endangered)||Limited aboriginal hunt||5|
There is ample evidence that wolves can play an important role in regulating prey populations and stabilizing ecosystems. Yet, MNR policy largely overlooks the ecological role of this top predator in Ontario’s ecosystems. Although the ministry’s wolf management strategy identifes that “managing a top predator” can be a challenge, it does so in the context of wolves competing with humans for wild prey. As outlined above, the conservation of biodiversity requires careful consideration of the ecological role of large carnivores and the subtle effects they might have on other species and entire biological systems.
To maintain Ontario’s biological diversity, it is important to understand the genetic diversity that currently exists. This includes identifying what is out there, where it is located, how much there is of it, and how at risk it may be. This can be as basic as correctly identifying which species live in Ontario. For example, the taxonomic classification of the eastern wolf – particularly whether it is a distinct species – can have significant conservation implications.
Although recent genetic studies, an independent review, and previous ECO reports have all argued that the eastern wolf should be recognized as a distinct species, MNR continues to consider the eastern wolf as a subspecies – Canis lupus lycaon – of the gray wolf (Canis lupus). This approach assumes that any fluctuations in eastern wolf population levels would likely be buffered by their close genetic connection to the larger gray wolf population in Ontario. Unfortunately, this (mis)identification has enormous bearing on conservation measures. Experts state that if eastern wolves were correctly recognized as a distinct species (with a total population of approximately 1,500 to 2,500), they would be “one of the most endangered canid species in the world.”
Prior to the arrival of Europeans, the range of the eastern cougar (Puma concolor, previously classifed as Felis concolor) covered almost all of Ontario, from the southern Great Lakes to Hudson’s Bay. This species was virtually exterminated from the province by the beginning of the 20th century. Eastern cougars have been regulated by MNR as an endangered species since 1971.
The number of sightings of eastern cougars has steadily increased in recent decades, with approximately 500 reported sightings since 2002. Genetic sampling of scat found in the wild, confrmation of cougar tracks, and other sightings and physical evidence leave little doubt that there are cougars in Ontario.
MNR, however, has typically dismissed cougar sightings, attributing them to cases of mistaken identity with other species. The ministry also suggests that some sightings likely were of escaped or released captive cougars. Therefore, as “non-native” species, the ministry assumed that these cougars did not need to be managed as endangered animals. In essence, any escapees were not viewed as true wildlife and, therefore, no agency was responsible for investigating whether they were part of a native population.
Although there are several subspecies of cougars in South America, experts argue that there is only one type or subspecies of cougar in North America. This evidence substantially weakens MNR’s case for differentiating between a “wild” cougar, an escapee, or a cougar that has naturally dispersed into Ontario from another jurisdiction.
MNR has done little, if anything, to manage Ontario’s eastern cougars in the four decades that they have been regulated as an endangered species. The ministry has neither attempted to systematically verify that a native population exists (except very recently at a highly localized scale) nor taken the alternative position that the population has been extirpated and, accordingly, worked toward its reintroduction or recovery. This inaction is not commensurate with the “at risk” status of this species or its likely historical role as a top predator in Ontario ecosystems.
The coyote (Canis latrans) is a medium-sized carnivore that quickly adapts to human-caused alterations to the landscape, such as the clearing of land for agriculture and development. Indeed, it is believed that coyotes were virtually nonexistent in the province until the onset of widespread European colonization in the 19th century. Humans created suitable conditions for coyotes through the massive deforestation and land-clearing for agriculture in southern Ontario. The spread of coyotes into southern Ontario was further assisted by the concerted effort to eliminate other predator species, such as wolves, thus creating a new ecological niche.
Coyotes adapt to intensive non-selective hunting and trapping pressures by increasing the frequency of litters and number of pups per litter. Indeed, some studies suggest that coyotes can withstand the harvesting of up to three-quarters of their population annually and not be locally extirpated for decades. Although some government policies treat coyotes as de facto vermin, it is virtually impossible to eliminate coyotes regionally in order to minimize perceived human-wildlife conficts.
Nonetheless, a suppressed or reduced coyote population can lead to a dramatic increase in other species, such as rodents or even feral housecats. These species in turn prey in greater numbers on other species, such as birds and small vertebrates. The result is a highly altered ecological system in a constant state of flux. Despite the importance of understanding predator-prey dynamics in coyote management, this aspect of their biology has gone largely unresearched. Therefore, the ecology of coyotes has been given little consideration in government policies, which treat coyotes either as fur-bearing mammals or pests.
MNR does not have an estimate of how many coyotes are in Ontario, stating only that they are “abundant.” Although there is significant variability between years, up to 3,400 coyotes have been trapped and 1,200 hunted annually in recent years. However, local population changes are usually attributed to natural mortality caused by disease, such as mange. Like most wildlife agencies in North America, MNR does not even attempt to ensure that coyote harvesting is done on a sustained yield basis.
The black bear (Ursus americanus) can be considered a keystone and indicator species in some circumstances, an important predator of newborn deer and moose, and a potentially important competitor for some prey species. MNR’s current black bear management policy, however, does not consider the potential ecological role of this species and instead treats black bears as game, focusing on sustaining hunting opportunities. While the ministry has drafted a new framework that identifes black bears as “an integral part of a functioning ecosystem and an important component of Ontario’s biodiversity,” this approach has not yet been formally adopted.
Harvests of black bears in some areas of Ontario may be occurring at unsustainable levels. After reviewing MNR harvest data, the Auditor General of Ontario recently noted, “While some areas of the province have an abundance of black bears … the ministry had incomplete information regarding black bear harvests, which could lead to decisions that do not support sustainability in all areas of the province.” Furthermore, some wildlife management units exceeded the allowable harvest of adult female bears. Unfortunately, the consequences of an error in population management are serious, because black bears have a low reproductive rate. Once a bear population is overharvested, it may take a decade or more to recover.
Another important component of ensuring the sustainability of a population is habitat management. Rather than manage black bear habitat directly, MNR primarily manages it indirectly through the forest management planning process for commercial timber harvesting. Some evidence suggests that an indirect approach to managing bear habitat is not effective.
While MNR’s management approach deals with this species in a uniform fashion, unique challenges can exist for subpopulations. For example, a lack of habitat corridors may have contributed to the genetic isolation of the Bruce Peninsula black bear population, a conservation issue not considered in MNR’s current policy.
The loss of biological diversity is, unequivocally, a global crisis. In response, the Ontario government has committed to protecting the genetic, species and ecosystem diversity of Ontario. Mammalian predators are an integral component of Ontario’s biodiversity that merits concerted attention by the Ministry of Natural Resources. It is no longer reasonable to manage mammalian predators primarily as pests to be eradicated or game and fur-bearing mammals to be harvested. A broader and better informed approach guided by the precautionary principle, which seeks to ensure the integrity of Ontario’s ecological systems, is warranted. Wild species should be maintained for their inherent value above all else. They should not be managed simply as a commodity to be rationed amongst stakeholder groups for consumptive (or even non-consumptive purposes), as seen in MNR’s recent management of wolves.
MNR’s approach to wildlife management typically focuses on the total numbers of a population. Generally, little attention is given to qualitative biological characteristics and interactions with other species. Put another way, as long as X number of animals is generally maintained, then Y number can be harvested annually, and thus, a management program is deemed to be sustainable. This approach inadequately considers the ecological role of species and the cascading effects that human influences can cause on biological systems. The potential to hunt or trap a species should be but one consideration within an integrated approach to their management.
Reliable population estimates are lacking for several of Ontario’s mammalian predators. For some species, such as marten and lynx, population estimates are essentially educated guesses that are arguably optimistic. There is a marked difference between what the theoretical capacity of a landscape may be for a species versus how many animals are actually physically present.
For some species, such as fisher and marten, MNR uses harvest indicators to estimate the size and health of populations. Unfortunately, relying on harvest indicators can result in erroneous findings. First, the ability to estimate population size is dependent on the accuracy of harvest indicators, which is in turn dependent on the adequacy of information from harvesters. The return rate of even mandatory MNR harvest surveys can be low. If an increased harvesting effort is not appropriately reflected in returned surveys, a population may decline without effecting a reduction in harvest. Second, even if reliable harvest indicators are available, the status of a population can change significantly without being reflected in the harvest sex ratio or age structure. Therefore, harvest trends are subject to considerable misinterpretation.
Even when Ontario’s mammalian predators have been recognized as being imperilled, such as with the eastern cougar, MNR has undertaken few direct measures to secure or recover their populations. This type of inaction has been attributed to the perceived fear within some government agencies that they will later have to “control” such species. However, it is far easier and significantly less controversial to conserve a wild species than to re-introduce it. Without doubt, MNR has the responsibility to ensure that such species are maintained and, ideally, recovered to the point where they are no longer at risk.
Very few policy decisions related to wildlife management are based strictly on biological data. For better or worse, other values – political, economic, social – often heavily influence the manner in which wildlife is managed. Nonetheless, concerted attempts should be made to acquire the best possible ecological knowledge to inform decision-making. The ECO believes that MNR should make the inter-specific dynamics and ecological functions of mammalian predators a research priority with the goal of better informing ministry policy. Even so, the ecological sciences should not be viewed as having immediate or indisputable solutions to all issues. The current lack of knowledge in some areas underscores the need for MNR to apply the precautionary principle to its management of mammalian predators.
The ECO recommends that MNR ensure that its wildlife management policies and models appropriately reflect the role of mammalian predators in ecosystems.
|This is an article from the 2007/08 Annual Report to the Legislature from the Environmental Commissioner of Ontario.|
Citing This Article:
Environmental Commissioner of Ontario. 2008. "Wildlife Management: Ontario's Mammalian Predators." Getting to K(No)w, ECO Annual Report, 2007-08. Toronto, ON : Environmental Commissioner of Ontario. 199-205.Fish and Wildlife Conservation Act