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1 Life History and Population Dynamics of Large Carnivores

Throughout this chapter, we refer to gray wolves (Canis lupus), mountain lions (Puma concolor), black bears (Ursus americanus), and grizzly bears (U. arctos) as “large carnivores.” Mountain lions and wolves are obligate carnivores, whereas black and grizzly bears are omnivores. Mountain lions, in fact, require the consumption of animal tissue to obtain taurine, an essential amino acid (Allen et al. 1997). These four species occur at much lower densities than their primary ungulate prey, and overall predator abundance is dictated by prey/food availability and competition between or among other large carnivores (Griffin et al. 2011; Hurley et al. 2011). We list morphological attributes and general life history characteristics of wolves, mountain lions, and black and grizzly bears in Table 24.1.

Table 24.1 Comprehensive comparisons of general morphology, reproductive, social structure and dietary characteristics of large carnivore species in North America
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1.1 Gray Wolves

Wolves are the only gregarious species of large carnivore in North America, utilizing a hierarchical social system of pack dynamics with a dominant breeding pair and subordinate wolves that share food acquisition and pup-rearing duties. Wolves are cursorial predators that chase and attempt to single out prey from a group by identifying an individual that exhibits vulnerability to predation. This strategy is sometimes misconstrued as wolves only killing the “sick and weak,” but it is more appropriate to state they take the most vulnerable prey items available (Mech 1970; Hebblewhite et al. 2003).

The reproductive strategies of wolves differ substantially from bears and mountain lions in that a dominant, or alpha breeding pair produce pups annually (Table 24.1). Pup production varies based on prey availability and local wolf densities. In areas of high prey availability and little competition, wolves can produce large litters or more than one litter/pack/year and sustain the ability to feed pups to independence (Boertje and Stephenson 1992).

1.2 Mountain Lions

Mountain lions are stalk and ambush predators, employing stealth to hunt prey across a breadth of habitats. As solitary hunters, mountain lions are the least observable, but most ubiquitous of the four large carnivore species. Mountain lions can produce kittens at any time of year (Jansen and Jenks 2012), unlike many similar-sized mammalian species. However, most research suggests mountain lions exhibit a birth pulse synchronicity in late-summer/early-fall when 2–4 kittens/litter are born (Jansen and Jenks 2012). Following birth, kittens remain in natal dens for 2–3 months, at which point they become mobile and begin traveling with their mother to feed on kills. Because most litters are born in late-summer, mountain lions are able to take advantage of peak ungulate birth periods in mid- to late-June when prey abundance is greatest. Mountain lions do not exhibit classic territorial behavior, but do scent-mark home range boundaries. Males also defend female breeding rights within their home ranges.

1.3 Black and Grizzly Bears

Black and grizzly bears maintain high levels of dietary plasticity and are considered true omnivores (Hristienko and McDonald 2007; van Manen et al. 2016). Even so, all bears are opportunistic predators and, in fact, certain individuals can become adept neonate predators (Barber-Meyer et al. 2008; Griffin et al. 2011).

Bears are unique among other North American large carnivores in that they spend approximately half the year hibernating in dens. While there remains scientific debate as to whether bears exhibit true hibernation, both black and grizzly bears spend most of the winter in a reduced state of physiological activity between November and March/April of the following year. The length of time spent within dens varies depending on sex and age of the individual and environmental conditions including latitude and elevation.

Most breeding among bears occurs in June, but the resulting fertilized egg undergoes a process termed “blastocyst arrest” where further embryonic development ceases until November. At that time, the egg implants on the female’s uterine wall and rapid fetal development begins (Haroldson et al. 2021). Because of this “delayed implantation,” of the embryo, all cub births occur at approximately the same time within the natal den, usually in late-January. Bears, especially grizzly bears, are also less fecund than other large mammals in North America (Haroldson et al. 2021; Table 24.1). Where most ungulates begin producing young by 1 1/2–2 years of age, grizzly bears generally do not reach sexual maturity until approximately 5 years of age and once cubs are born, they spend 2 full summers with the maternal female. Thus, grizzly bears produce on average only 2–3 cubs every 3 years after the age of 5 (Haroldson et al. 2021).

2 History of Large Carnivores in North America

Human emotions concerning large carnivores have always varied from complete hatred to that of idolatry and worship (Hovardas 2018). Thus, to provide a representative and accurate account of large carnivores in rangeland settings today, it is necessary to delve into the historical record and describe human-caused perturbations that affected these species from the period prior to European settlement of the western U.S. through today. Before Western expansion, Native American peoples long maintained traditional oral accounts of their interactions with large carnivores. Many of their stories described the mystical kinship between human beings and these animals and many behavioral attributes of bears and wolves were incorporated into tribal dances and ceremonials (Neihardt 1932). Often, tribes viewed bears (both black and grizzlies) as familial, but Native Americans also actively hunted them depending on the tribe or use of the harvested animal (i.e., meat, clothing, ceremonial; Young and Goldman 1946). In fact, the ability to successfully take one of these animals often resulted in great credit and adulation to the successful hunter from both tribal members and enemies alike.

As westward European settlement progressed during the middle nineteenth century, attitudes of many pioneers toward large carnivores were vastly different from the country’s original Native American inhabitants (Thirgood et al. 2005). Some of the more famous/infamous early accounts of human interactions with carnivores, especially bears, were lavishly recounted in the journals of Lewis and Clark (Leopold 1933; various journals of Lewis and Clark) and countless reports, stories, and representations (both factual and sensationalized) from the era’s iconic mountain men and early naturalists. Wolves, mountain lions, and grizzly bears were perceived as direct threats to human safety, with accounts of humans being killed by mountain lions recorded as early as 1747 (Young and Goldman 1946). Following the West-wide American bison (Bison bison) slaughter of the 1870s, domestic livestock took their place. The behavioral naivety of domestic cattle and sheep allowed for easy exploitation by native carnivores (Riley et al. 2004). Direct (e.g., human safety) and indirect (i.e., livestock, property, and ungulate population) impacts from large carnivores were met with aggressive removal actions. Similar reductions in populations of other big game species in addition to bison were occurring as the result of uncontrolled market hunting and large-scale habitat destruction.

While the hunting and/or killing of carnivores by individual settlers occurred throughout westward expansion, the enactment of bounties and regimented governmental removal likely resulted in the greatest impact to large carnivore abundance and distribution in North America (Fig. 24.1; Leopold 1933; Caughley 1977; Cougar Management Guidelines Working Group 2005). For example, the Federal government systematically promoted and engaged in wolf eradication efforts across the lower 48 states (Mech 1970; US Fish and Wildlife Service et al. 2011).

Fig. 24.1
4 maps with carnivore species. a. The grizzly bear range is found in North America, the northwestern parts of Canada, and the west coast. b. Black bears in North America cover the entire northern region. c. Mountain lions in North America are found in the western United States and western Canada. d. Gray wolves in North America are found in Canada and the northern United States.

Comparative distributions of large carnivore species (clockwise from top left; grizzly bear [Ursus arctos], black bear [U. americanus], gray wolf [Canis lupus] and cougar [Puma concolor]) in North America, demonstrating changes from historical to current range for bears and wolves whereby darker shades represent current distribution. Top left; historical and current grizzly bear range in North America (Haroldson et al. 2021); top right, historical and current black bear range in North America (adapted from International Union for Conservation of Nature Archives); bottom right, historical and current range of gray wolves in North America (adapted from Wyoming Game and Fish Commission 2011), and bottom left; current mountain lion range (darker shaded area) and documented range expansion in North America (adapted from LaRue 2018), shaded dots represent verified mountain lion presence by county outside of current distribution indicative of recolonization of historic mountain lion range (LaRue 2018)

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Following establishment of Yellowstone National Park in 1872, a slow evolving change in viewpoints and attitudes toward wildlife and wildlands began. At first, only a small number of sportsmen-conservationists, including George Bird Grinnell and others, raised the alarm. They understood the finite nature of wildlife after experiencing first-hand the dramatic reduction of bison and other big game species. Later, hunters including President Theodore Roosevelt, Forest Service Chief Gifford Pinchot, and Congressman John Lacey, along with Grinnell and others, made the first substantive reversals of the environmental destruction that occurred during the late-1800s. Sportsmen’s groups and management agencies then began the long process of reestablishing game populations across the West.

However, adoption of regulated management of carnivorous animals lagged well behind that of game species such as deer (Odocoileus spp.) and elk (Cervus elaphus). As a result, wolves were reduced to a few remnant individuals and/or packs in the most rugged, inaccessible terrain. In most of their historic ranges, they were considered to be functionally extirpated by the mid-1900s (Mech 1970; Riley et al. 2004). Similarly, grizzly bears were reduced to less than 2% of their original range in the lower 48 states, with extant populations found only in remote/protected areas such as Yellowstone and Glacier National Parks and surrounding wilderness areas (White et al. 2017; Haroldson et al. 2021). While mountain lion populations were greatly reduced as well, their secretive and elusive behavioral characteristics made them less susceptible to large-scale harvest and allowed them to maintain breeding populations in the more mountainous and rugged areas across the western U.S. and Canada (Riley et al. 2004; Hornocker and Negri 2010). Black bear populations were reduced through direct human harvest or widespread habitat perturbations (i.e., logging, wildfire, intensive livestock grazing, and the resulting erosion) occurring concurrently with wide scale predator reduction activities recounted above (Hristienko and McDonald 2007).

Persecution of large carnivores continued unabated throughout the first three quarters of the twentieth century. However, changing public attitudes during the environmental awakening of the 1960s eventually resulted in the termination of bounty payments and wide-scale poisoning of predatory species by the 1970s in most portions of North America. In addition, changing land use practices and adoption of new livestock husbandry practices (referenced throughout this book) often times reduced the necessity to lethally control large carnivores.

The rebound of large carnivores is one of the greatest conservation success stories of the twentieth century (Bennett 1998; Pyare et al. 2004; US Fish and Wildlife Service 2017a). Populations of wolves, mountain lions, and black and grizzly bears that were on the brink of extinction and/or extirpated across wide swaths of their historical ranges are now stable to increasing and expanding back into formerly occupied habitats throughout North America (Fig. 24.1). For instance, gray wolves in the western U.S. have expanded their range since being reintroduced to the Greater Yellowstone Ecosystem (GYE) and wilderness areas of central Idaho in the mid-1990s in conjunction with natural dispersal into suitable habitats in other portions of the U.S. and Canada (Cullingham et al. 2016; United States Fish and Wildlife Service et al. 2020). Similarly, mountain lions and black bears have naturally re-colonized large areas of their historical ranges in western North America, with mountain lions even expanding eastward into areas bereft of the big cats for the past 150 years (Thompson and Jenks 2010; LaRue and Nielsen 2011). Lastly, grizzly bear populations in the GYE and Northern Continental Divide Ecosystem (NCDE) have experienced a dramatic increase in abundance and distribution, surpassing biologically suitable and socially acceptable habitats in each area (Bjornlie et al. 2014; US Fish and Wildlife Service 2017a, b).

As public attitudes toward large carnivores changed, many aspects of their behavior and biology remained unknown. The implementation of new and innovative techniques to capture, handle, and monitor large carnivores, in conjunction with development of radio telemetry in the 1960s, opened up many opportunities to better understand large carnivore biology (Fuller et al. 2005). The ability to affix radio transmitters on these species provided insight into the movements of large carnivores that was previously unavailable. Additionally, radio monitoring led to a greater understanding of large carnivore life histories and provided important empirical data illustrating how they interact with humans, livestock, and native prey across the largely intact wild rangeland settings of the American West.

Research pioneers Frank and John Craighead were the first to fit a grizzly bear with a radio collar to track its movements in the GYE (Craighead et al. 1974; for an amazing representation of initial marking of a grizzly bear in Yellowstone National Park by the Craighead’s search for “Craighead’s grizzly bear” on Youtube™). At the same time, Maurice Hornocker and his renowned houndsman Wilbur Wiles were the first persons to fit a mountain lion with a radio-tracking collar in the Idaho Primitive Area (Hornocker 1969; Seidensticker et al. 1973) while L. David Mech was gaining valuable insight into wolf ecology through the use of radio telemetry in northern Minnesota (Mech 1970). As wildlife professionals gathered more detailed biological information concerning large carnivores, agencies began developing management plans and strategies for black bears and mountain lions, and later grizzly bears and wolves using these new data.

Today, because grizzly bears are considered a threatened species under the Endangered Species Act of 1973 (ESA) in the lower 48 states, they are somewhat compartmentalized from a management planning perspective (US Fish and Wildlife Service 2013, 2017a). Gray wolves are also unique because, despite being functionally extirpated from the West, the U.S. Fish and Wildlife Service reintroduced wolves into the GYE and central Idaho in 1995–1996 (US Fish and Wildlife Service et al. 2011). After decades of effort, gray wolves are now abundant in many areas across Idaho, Montana, and Wyoming (US Fish and Wildlife Service 2020), with continued expansion of the species into Oregon, Washington, California and Colorado (US Fish and Wildlife Service 2020). Mountain lions and black bears remain solely under the purview of state management planning efforts.

3 Understanding Large Carnivores Through Research and Monitoring

With the possible exception of wolves, large carnivores on western rangelands are very difficult to enumerate because of their cryptic nature and relatively low abundance. However, recent technological advances in telemetry, remote sensing, and statistical analyses have resulted in more applied research and monitoring studies and a greater ecological understanding of these species. Additionally, improved data analyses have allowed managers to implement more science-based decisions and strategies to inform conservation and management of these apex predators.

Entire books and numerous book chapters have been devoted toward research rigorously evaluating wolves (Mech 1970; Carbyn et al. 1995), mountain lions (Anderson et al. 2010; Jenks 2011), and bears (Powell et al. 1997; White et al. 2017; Haroldson et al. 2021) and should be reviewed by any serious student of large carnivore ecology. For purposes of this chapter, the following sections highlight the most widely-employed research and monitoring techniques for individual large carnivore species.

3.1 Gray Wolves

In Canada and Alaska, where wolf populations are stable to increasing across the majority of their range, rigorous research and management programs are regularly implemented to support continuing hunting and trapping activities. Within the Continental U.S., however, wolf populations must be monitored because either they are currently listed as Threatened/Endangered under ESA, or have been recently delisted, and agencies must provide data to support continued state-controlled management. For example, the Northern Rocky Mountain states of Idaho, Wyoming, and Montana are each required to maintain an annual population or at least 150 wolves and 15 breeding pairs (defined as two adult wolves with at least two pups, US Fish and Wildlife Service et al. 2011) to maintain federal recovered status. These recovery criterion must be achieved even when dealing with conflict issues such as livestock depredation.

To ensure these types of fine-scale recovery criterion are achieved, agencies utilize radio-marking of select individuals within packs. By marking one or more individuals within a pack, annual dynamics of the entire pack can be monitored (Hebblewhite et al. 2003). Through subsequent ground, aerial, and global positioning system (GPS) tracking, den sites can be determined, accurate pup counts can be taken, and rendezvous sites can be identified to assist in monitoring changes in pack size and pup survival throughout summer and fall. Maintaining radio-marked individuals within packs can also assist in determining wolves responsible for depredation or other conflicts (Breck et al. 2011; Bradley et al. 2015) in areas overlapping livestock production. This type of research and monitoring is expensive and time consuming. However, managers must often weigh these costs against recovery/research objectives and/or public and agency scrutiny.

The vagile nature of wolves requires constant research/monitoring adaptability. As wolf populations increase and expand, research efforts are beginning to focus on questions regarding livestock predation, impacts to ungulates, and interactions among mountain lions (Griffin et al. 2011; Hurley et al. 2011) and bears (Barber-Meyer et al. 2008) in multi-prey/multi-carnivore systems. Additionally, GPS technology allows fine-scale assessment of wolf movements and can be used to pinpoint locations of kills and feeding sites [originally developed and widely used for mountain lions (Anderson and Lindzey 2003; Knopff et al. 2010; Wilckens et al. 2015)]. Kill site clusters provide empirical data used to determine kill rates and prey composition (Clapp et al. 2021), and identify den and rendezvous sites. GPS data and cluster analyses are being employed across all carnivore taxa, including the 4 species discussed in this chapter.

3.2 Mountain Lions

Because mountain lions are the most reclusive of North American large carnivores, there are techniques that enable agencies to monitor population abundance and/or trend when used in tandem with management and harvest strategies,. The “gold standard” for evaluating abundance of mountain lion populations is through intensive capture, radio-marking, and monitoring techniques (Cougar Management Guidelines Working Group 2005; Jenks 2011). While costly, marking a representative sample of a lion population provides baseline information regarding abundance, survival, fecundity, natality, and recruitment. Further, evaluation of fine-scale movement patterns can provide detailed insight into resource selection and interactions with other species; including use of human-occupied areas (Anderson and Lindzey 2003; Fuller et al. 2005; Knopff et al. 2009; Tomkiewicz et al. 2010).

Realistically, however, not all mountain lion populations can, or need be studied this intensively. The cost-prohibitive nature of capture-collar-monitor techniques have often required managers to develop more creative, less expensive, and non-invasive monitoring techniques; ranging from track and hair surveys (ground and aerial, Van Sickle and Lindzey 1991; Sawaya et al. 2010), remote-camera surveys (Karanth and Nichols 1998; Kelly et al. 2008; Hughson et al. 2010), scent-station surveys, or combined iterations of these methods (Choate et al. 2009; Russell et al. 2012) with differential success depending on the size of the study area and research objectives.

The use of “biopsy darts” has also been used to assess population status in many areas of mountain lion range (Beausoleil et al. 2016; Proffitt et al. 2020), whereby an animal is pursued by trained dogs, brought to bay, and then “marked” by obtaining a sample of tissue from a biopsy dart. Animals are “marked” in this fashion to obtain a genetic subset of the entire population. Then as mountain lions are subsequently harvested or lost through other forms of mortality (i.e., highway strikes, conflict removals, etc.), these mortality “recaptures” are used to derive an estimate of a local population using a modeling technique referred to as “mark-recapture/mark-resight and/or capture/mark/recapture” (White and Burnham 1999; Buckland et al. 2001). The implementation of these types of models has grown exponentially in recent years (Burnham and Anderson 2002; McClintock et al. 2006; R Development Core Team 2019) and will be discussed in greater detail in Sect. 24.3.5 of this chapter.

Another genetics-based, noninvasive monitoring technique is the use of scat-detection dogs (Wasser et al. 2004). These highly-trained canines can differentiate mountain lion scat from other species along systematic transects. The resulting scat “detections” are used to differentiate individual lions and calculate local population density. Scat detection is also very useful to document presence/absence of these large felines in areas of range expansion.

3.3 Black Bears

Agencies use capture/collar/monitoring techniques to gather baseline information concerning black bear populations. The method, in addition to the techniques previously described for wolves and mountain lions, is particularly useful to determine black bear range expansion.

Also similar to wolves and mountain lions, the use of genetic monitoring techniques is gaining currency in the development of black bear population estimates. In particular, hair-snare surveys employ a relatively inexpensive, non-invasive sampling technique; whereby a barbed-wire fence is erected around a non-food suspended lure. As a bear visits and investigates the lure, it passes over or under the fencing, shedding a convenient clump of hair, thus providing a genetic sample (Gardner et al. 2010; Gurney et al. 2020). Samples obtained in hair snares are then analyzed using an additional iteration of the mark-recapture technique (Borchers and Efford 2008). Data gathered in this manner have been used to develop clustered sampling techniques (Humm et al. 2017) that provide less logistically restrictive, yet accurate estimates of abundance and population trend, and can be very helpful when designing management strategies for this species. When implemented in a systematic approach across years, managers can derive point population estimates and provide statistically robust evaluation of management strategies to document population increase, stability, or decline depending on objectives.

3.4 Grizzly Bears

Techniques discussed throughout this section have been employed to better understand grizzly bear population dynamics and genetic diversity, with hair-snare and other genetic mark-recapture methods being employed throughout western Canada and Alaska (Paetkau et al. 1998; Boulanger et al. 2004). Additionally, advances in GPS technologies have been used for fine-scale analysis of brown bear movements and been used to determine potential barriers to gene flow in western Canadian provinces (Proctor et al. 2002; Boulanger and Stenhouse 2014).

Because grizzly bears have been listed as a threatened species in the lower 48 states since 1973, research and monitoring efforts are generally more intensive in the Continental U.S. (US Fish and Wildlife Service 2017a). As a result, the GYE and NCDE populations have been intensively studied for decades (Apps et al. 2004; Mace 2004; Schwartz et al. 2014; van Manen et al. 2016; White et al. 2017). In the GYE, researchers/managers retain an annual representative sample of marked animals [using both Very High Frequency (VHF) and GPS radio-collars] to gather data on survival, mortality, reproduction, dispersal, movements, habitat use, and overall population dynamics. Select areas within the GYE are very conducive to aerial observations of bears due to favorable topographic and vegetative features. Thus, aerial observation surveys are used in conjunction with telemetry data and ground observations to estimate annual abundance of the population. Each year, 70–90 grizzly bears are tracked through telemetry and methodical records of bear mortality, conflicts with humans, and other myriad parameters that allow for fine-scale evaluation of this increasing grizzly bear population and its potential hazards and threats (Schwartz et al. 2010). Similar techniques have been employed in the NCDE.

The commitment and foresight of attaining long-term, systematically-collected datasets of these intensively-monitored grizzly populations has enabled researchers to continually re-examine these data while taking advantage of the evolving spectrum of advances in statistical and technological analyses. Program MARK™, R™, and derivations of this program (White and Burnham 1999; R Development Core Team 2019), for example, have increased the capability and statistical rigor of analyses for wildlife populations (Sells et al. 2018; Bissonette 2019).

3.5 Capture/Mark/Recapture Estimation Techniques

Capture/Mark/Recapture (CMR) methodologies have become the foundation for most population abundance and density estimates for large carnivores and many other wildlife populations (Amstrup et al. 2006; Batemen et al. 2013; Borchers et al. 2015). Techniques developed to noninvasively collect deoxyribonucleic acid (DNA) from wild animals has led to rigorous systematic monitoring programs that provide local density estimates. As previously mentioned, hair snares have been widely used for both black and grizzly bears and efficiency has increased to the point that this method has been implemented across North America. Spatially explicit capture-recapture (SECR; Kristensen and Kovach 2018) sampling has increased the efficacy and applicability of hair snare sampling on a larger scale for ursids and other wildlife populations (Morehouse and Boyce 2016; Humm et al. 2017). Additional creative methods to obtain DNA have been employed for mountain lions (Sawaya et al. 2010; Beausoleil et al. 2016) and less frequently for wolves (Caniglia et al. 2012; Stansbury et al. 2014). The common denominator among all these techniques is the importance of maintaining an adequate marked sample of the population to ensure statistical rigor for local population estimates (Borchers et al. 2015).

Biologists also use individual animal characteristics to estimate localized abundance through the use of camera-traps (Davidson et al. 2014; Mattioli et al. 2018), observations of verified tracks or individually identifiable animals, noninvasive genetic techniques including hair snares and scat detection dogs, and combinations thereof (Davidson et al. 2014; Stone et al. 2017; Mattioli et al. 2018; Murphy et al. 2018).

All aforementioned sampling methods are employed through some type of measured grid and/or transect system to extrapolate abundance/densities on a local scale without expanding results beyond the merits of the study design (Newey et al. 2015). Estimation of population trends allow researchers and managers to evaluate various management strategies/harvest regimes and answer questions salient to the public and/or those individuals impacted (directly or indirectly) by large carnivores.

Recently, integrated population modeling (IPM) techniques have been implemented for black bears, grizzly bears, and mountain lions (Arnold et al. 2018). IPMs were initially developed for ungulates, but the technique has been successfully adapted for large carnivores and other wildlife species. The interpolated model allows input parameters that implement Bayesian statistical probabilistic methodologies to provide insight into particular components of a wildlife population (Arnold et al. 2018) and projected perturbations to calculate potential outcomes for the population(s) in question. The more accurate the input parameters, the more self-correcting and reliable the model outputs become. This technique was used to evaluate mountain lion abundance and predation on elk in the Bitterroot Mountains of Montana (Proffitt et al. 2020). IPM also has merit for bear populations across the West.

The intra- and interspecific interactions among carnivores and their relationships with multiple prey species has fostered a plethora of attempts to design research to better describe and quantify predator–prey dynamics (Moll et al. 2016; Montgomery et al. 2019). Because many Western rangeland ecosystems contain intact mammalian guilds, they, in particular, provide a robust opportunity to examine these interactions. Multiple predator–prey systems exhibit social dynamics and hierarchies between and among carnivores, with mountain lions and black bears serving as subordinate predators to wolves and grizzly bears (Griffin et al. 2011; Elbroch et al. 2020). Because of dwindling mule deer (O. hemionus) and moose (Alces alces) populations in localized situations, researchers are also attempting to quantify whether predation is acting as an additive or compensatory form of mortality (Griffin et al. 2011; Pierce et al. 2012; Proffitt et al. 2020).

Each land system experiences its own unique dynamic, fluctuating as populations move toward a natural state and homeostasis. However, applied research suggests multiple carnivore systems may impact prey populations by reducing offspring/maternal female ratios (Barber-Meyer et al. 2008; Proffitt et al. 2020) and causing prey to increase vigilance, select for smaller group sizes, and use the landscape in a dispersed distribution (Griffin et al. 2011; Elbroch et al. 2020). All of these evolving selective pressures are directly influenced by livestock grazing and changing land use practices, regardless of area. Agencies and individuals responsible for managing the land, the livestock, and the wildlife must continually work to understand these ever-changing targets.

3.6 Management Strategies

As stated previously, research and monitoring efforts provide data to understand the daily lives of large carnivores and enable managers to develop management strategies that maintain and/or regulate population densities and abundance; depending on local management objectives and public opinion. This section briefly highlights some of the tools used to manage large carnivore populations in rangeland settings. However, it is important to emphasize that “management” is more encompassing than just developing hunting seasons or population reduction/augmentation programs. In the context of large carnivores, conflict management must be intricately interwoven with harvest-driven management/conservation strategies. Our repetition of holistic management programs is purposeful in that all information discussed within this chapter regarding wolves, mountain lions, and bears are integral components of an overall “successful” management program for these species and/or populations.

Regulated hunting, or harvest, is a primary method of population management for many wildlife species. Currently, all states and provincial agencies that use hunting as a management tool for wolves, mountain lions, and black bears rely on some form of annual monitoring, including harvest data, to evaluate population status. Data gathered from harvested animals provide inferences of the population’s sex and age composition, density of mortality per unit area, and other useful information for managers (i.e., hunter success, harvest rates, hunter satisfaction). These data are ultimately used to evaluate efficacy of management strategies.

Wildlife in the U.S. is a publicly-owned resource and managed under the North American Model of Wildlife Conservation, where stakeholder input, science-based management techniques, and professional expertise combine to develop effective hunting strategies that attain desired population densities for game species (Bleich and Thompson 2018). While the North American Model may have been developed with ungulate species in mind, it is wholly applicable to large carnivores as well because they are a vital component of the public trust. The driving factor for how hunting may be used to achieve population reduction/stability/increase is rooted in the species’ population density and socio-political parameters that influence localized objectives for population abundance (i.e., public desires, livestock density, proximity to urban/suburban areas, ungulate herds, and habitat quality). For example, Hristienko and McDonald (2007) suggested black bear management objectives should emphasize maintaining viable black bear populations, safeguarding human safety and livelihood, and satisfying the needs of various stakeholders; while considering fiduciary responsibilities and accountability.

By and large, agencies responsible for large carnivore management employ the use of quotas, mortality limits, and season length/timing restrictions to move a population toward specific population objectives. Large carnivore management units and hunt areas are often developed using local population densities, topography, the amount of contiguous habitat present, and other landscape features representing a localized population. Historical population data and previous research/professional expertise are vitally important to devise hunt areas that accurately represent local carnivore and prey populations. The use of management units and hunt areas allow managers to direct harvest to specific areas on a localized level. Life history and movement patterns of carnivores are enveloped into these strategies, whereby animals removed from the population will be replaced by other animals within the population or from surrounding populations [sometimes referred to as source/sink management (Robinson et al. 2008)]. Managers attempt to have a mixture of harvest objectives for hunt areas (i.e., reduce, stabilize, augment) within larger management units. Most states and provinces require mandatory checks of harvested wolves, mountain lions, and bears to ensure sex and age data are collected from animals taken by hunters. Data acquired during mandatory checks are used to evaluate harvest trend, hunter satisfaction, and population composition from each animal.

The importance of utilizing human dimensions methodology in large carnivore management is discussed later in this chapter. However, when evaluating hunting programs, most agencies adopt some form of harvest survey to assess the quality of local wildlife populations from the sportspersons’ perspective. The use of harvest surveys assists managers in evaluating the perceptions of successful and non-successful hunters by providing information on their overall effort, species observed while afield, and intangibles otherwise difficult to gather. While this information is not analogous to the rigorous quantitative data acquired from intensive research or monitoring efforts, it is an invaluable introspective into wide-ranging public attitudes from stakeholders that are personally invested in large carnivore hunting and management.

4 Large Carnivore Interactions with Humans and Livestock

Wolves and grizzly bears have had an increasing impact on rangeland livestock operations as populations have expanded beyond established recovery zones over the last 25 years. For example, in Wyoming, Montana, and Idaho, grizzly bears now persist in human-dominated agricultural landscapes (Bjornlie et al. 2014) that incur much higher conflict potential in the forms of livestock depredation, property damage, and human safety. Similarly, mountain lion and black bear conflict has increased as their populations have increased in rangeland settings.

Although addressed elsewhere in the book (Chap. 28: Living with Predators), it is important to address specific issues regarding large carnivore conflicts in this chapter. One of the more vital components of large carnivore conservation is the importance of managing and reducing conflict potential from large carnivores to increase human tolerance for, and promote long-term conservation of these species on the landscape. In addition, active large carnivore conflict management programs provide vital techniques and promote methodologies for the public to proactively reduce conflict. These programs can also provide an avenue for producers to reduce the potential and actual predation of their livestock.

There is not a standardized definition of conflict, but it involves interactions between humans and wildlife that result in property damage, agricultural damage, or public safety issues, and usually requires verification from a trained professional. Verification of damage is important because it provides an empirical way to track annual trends in conflict and also assists in identifying potential mitigation or resolutions in regards to conflict management.

Approaches to mitigating large carnivore conflicts can be both proactive (see outreach and education later in the chapter) and reactive. When proactive approaches are unsuccessful and conflict occurs, managers must respond rapidly to reduce or eliminate the impact using multiple methods. Professionals that deal with large carnivores realize that controversy is inherent from virtually all viewpoints and most state and provincial agencies have protocols and guidelines in place to deal directly with human-carnivore conflicts. The high level of public scrutiny and opinion regarding large carnivore conflict and agency response to that conflict always requires a high level of professionalism and consistency in approach. Whether dealing with a livestock producer that has lost calves to wolves or an advocacy group outraged by the lethal removal of a bear that has killed livestock, consistency projects objectivity when assessing conflict management.

4.1 Human Safety

The reality of large carnivores and humans traversing the same habitat means there are factual human safety risks that must be considered and addressed. Encounters that result in human injuries or fatalities are extremely rare, but when they do occur, they directly affect those close to the person attacked and heavily impact the human psyche and overall tolerance for carnivores (Herrero 1985; McNay 2002; Quigley and Herrero 2005). Due to the high priority and contentious nature of these events, most agencies have some type of team specially trained to deal with them. State and Provincial “Wildlife Human Attack Response Teams” (WHART) and close derivatives consist of highly specialized professionals that respond to wildlife attacks with a multi-faceted systematic approach as to how the investigation is handled. The team operates with a system designed to cover jurisdictional responsibilities, media coverage/control, and logistics in regards to wildlife capture. All human injury/fatality situations are dynamic and very specific to the individual causation of the event, but the consistent priority is immediate response to these situations in the name of human safety.

4.2 Livestock Depredation

Livestock depredation is the most relevant form of human/large carnivore conflict to be addressed in this chapter given Rangeland Wildlife Ecology and Conservation deals specifically with rangeland management. From a pragmatic perspective, increased depredation of livestock has occurred in many areas of the western U.S. and Canada in recent decades, likely a function of greater abundance and wider distribution of carnivore species coupled with an increase in smaller “hobby farms” that acquire more atypical domestic species prone to depredation (i.e., llamas, alpacas, poultry, swine, etc.). While this chapter focuses mainly on depredation of domestic cattle and sheep (US Department of Agriculture et al. 2019a, b), several of the strategies to reduce conflict potential with these species are directly applicable to multiple other domestic species.

There are multiple proactive infrastructural updates that can be implemented to reduce large carnivore conflict, depending on livestock type and herd size and the predatory behavior of the specific carnivore. If producers have the ability to night-pen or use electric fencing around livestock, it can be a very effective tool to reduce depredation from canids and ursids (Breck et al. 2011). The use of electric fencing has also been readily employed for poultry, swine, sheep, and smaller cattle/horse operations (Bodenchuck 2011). In addition to reducing livestock depredation, electric fencing has been used to alleviate crop damage from black and grizzly bears. There are temporary approaches such as fladry/turbo-fladry (Davidson-Nelson and Gehring 2010) that can be used at specific times of year (calving/lambing season) to deter wolf depredation, but should be considered a temporary fix as wolves acclimate to the presence of fladry. Free-range grazing and/or larger cattle/sheep operations generally do not have these options; however, there has been success with electric-fence night penning of sheep depending on sheep band-size (Wyoming Game and Fish Department unpublished data). When using any type of electrical deterrence is it imperative to repeatedly evaluate amperage and efficacy of the system, as many large carnivores will continue to test these types of devices (Smith et al. 2018). When operating properly, these methods provide a very efficacious means of reducing conflict, but they are obviously not pertinent to all livestock producers.

For larger livestock herds in open range settings, depredation risk is largely related to abundance of livestock and abundance of large carnivores (Wells et al. 2019). Most open range livestock producers employ the use of riders to stay with or check their sheep and cattle herds, The efficacy of range riding depends on herd size and rider experience (Eklund et al. 2017; Wells et al. 2019). Range riders do not eliminate depredation, especially in rough terrain with high carnivore densities and/or multiple carnivore species. However, adept riders can locate depredated animals and alert management agencies to evaluate potential strategies to reactively mitigate conflict.

Many times, domestic sheep producers employ the use of guard dogs in open range bands/herds for protection from wild canids, felids, and ursids. Dogs can be highly effective and work well when used with other techniques for certain species of predators. However, some precautions may be necessary for use of guard dogs (species of dog, total number of dogs/sheep band) in areas of wolf depredation as wolves may actively seek out and kill livestock guard dogs (Mosley et al. 2020).

Depending on the depredating species involved, additional strategies may be used including hazing/aversive conditioning, capture and relocation, and lethal removal (Bradley et al. 2005; Karlsson and Johansson 2010). While not palatable to some (Slagle et al. 2017), targeting and removing offending individual(s) responsible for livestock depredation is an effective and viable approach to reduce further depredation (Anderson et al. 2002) and is a methodology often used within a suite of options by many management entities. It should be noted that certain species or even individuals of a species may incur localized interest and sometimes federal protections (e.g., grizzly bears in the lower 48 states). Therefore, lethal removal is heavily scrutinized and sometimes disparaged (Slagle et al. 2017).

In terms of cause-specific mortality, mountain lions are generally more associated with sheep depredation, although cattle depredations occur in the southwestern U.S. and Mexico (Bodenchuck 2011; US Department of Agriculture et al. 2019a). Wolves and grizzly bears will depredate cattle and sheep when sympatric depending on vulnerability, density, and/or pack size of carnivore species present. Intensive herding of sheep on a 24-h basis has been effective at reducing predation by wolves, but the technique is obviously labor intensive (Stone et al. 2017).

Another component of conflict mitigation entails reducing the financial impacts of livestock depredation to producers through damage compensation programs. Many states and provinces provide some type of compensation for verified livestock depredation depending on the depredating species involved, but methodologies among agencies vary. Compensation programs do not provide a source of income for producers, but rather attempt to offset some of the costs of maintaining species such as wolves and grizzly bears where they overlap with livestock production (Jacobs and Main 2015). Maintaining wild open landscapes is critical for both livestock producers, large carnivores, and other wildlife. Building or at least maintaining a tolerance for carnivore presence can serve as a mutualistic benefit for carnivorous species and human counterparts alike. Perhaps the most significant point in regards to reducing large carnivore depredation potential is that there is no single technique that eliminates depredation outside of removing every carnivore and every domestic livestock species on the landscape (unrealistic); however, implementing multiple nonlethal/lethal techniques (as described above) can mitigate conflict to the point that both wild and domestic species persist.

4.3 Property Damage

Black bears can cause substantial property damage while obtaining anthropogenic foods (Messmer 2009; Lackey et al. 2018). Black and grizzly bears can also damage property while depredating or attempting to depredate domestic species (i.e., poultry, swine, sheep, goats). A significant source of damage from bears can occur in regards to honeybee (Apis spp.) apiaries (Messmer 2009). The most reliable method to reduce apiary damage is the use of well-maintained electric fencing (whether permanent or temporary). Since apiary damage can cause tens of thousands of dollars of damage, many agencies work closely with honeybee producer to proactively reduce that potential. Property damage caused by mountain lions and wolves rarely occurs. However, there have been instances of mountain lions breaking into chicken coops or similar outbuildings, and the authors are aware of one instance where a basement screen door was destroyed by a mountain lion in an attempt to depredate domestic housecats (Felis catus).

5 Large Carnivore Conflict Resolution

The previous section highlighted management strategies to mitigate and reduce conflict between large carnivores and humans, but managers always realize that before the first electric fence is erected or a capture effort initiated on a depredating animal, the fundamental foundation for effective large carnivore management lies within an active outreach and education program. While large carnivores play an important role in ecosystem function on western rangelands and provide intrigue and interest for the general public, they also cause consternation and can result in significant property or livestock damage for people that live and work in areas where large carnivores occur. Thus, information and educational programs are considered to be the foundation of a successful conflict resolution/mitigation program. Similarly, educational programs have evolved to increase efficacy of management actions and proactively resolve human dimension issues (Bennett 1998).

5.1 Information and Outreach

There are many options to efficaciously provide public outreach concerning large carnivores. For decades, nearly all public outreach was done via face-to-face interactions in classrooms, workshops, and symposia, or while visiting with people in coffeeshops, bars, or other social settings. Some gatherings were large and some small, but all were held with the goal of educating people about large carnivores and their management (Johnson et al. 1993; Bennett 1998). Additionally, most states and provinces had well-developed public meeting formats, as these techniques are still commonly used to gather input on annual hunting seasons and other management regulations for big game species. Prior to the advent of social media and virtual meetings, many citizens considered attendance at in-person public meetings as the best way to learn what was going on and voicing opinions to their local management agency.

As large carnivores expanded in number and distribution, most states and provinces adopted similar meeting formats to inform the public about pertinent management issues. In many cases, the public’s understanding and knowledge of large carnivore issues was based more on preconceived notions, hearsay, and hyperbole than reality. During the aforesaid understanding and knowledge of the ecology of the species was brought into these safety curriculums as well as building in a behavioral component on what one can do when recreating, working, and/or living in “large carnivore country” to increase human safety and reduce the risk of conflict.

As agencies built upon the strengths and weaknesses of previous work, many meetings and workshops turned into “community programs,” which greatly increased their efficacy by stressing that homeowners and private landowners were part of the solution rather than being told what to do by governmental agencies. An example of this approach includes implementation of Bear Wise and Bear Aware programs in the Northern Rocky Mountains (IGBC 2019), especially in areas where grizzly bears occur. These types of programs focus on using improved community awareness, public education, and creative problem solving to deal with issues such as grizzly bears in cornfields and chicken coops. Public ownership facilitates active coordination, thereby increasing tolerance for large carnivores and furthering trust and collaboration between the public and governmental agencies (Guynn and Landry 1997). In recent years, many non-governmental agencies have become involved in safety programs, especially with grizzly bears and wolves. The key to success in any outreach program is communication and coordination among all parties involved in issues related to large carnivore conflict—where efforts have failed is where a key landowner or agency component is left out, which can create animosity (Dickman et al. 2013).

Technology has grown exponentially in regards to relaying information, as have outreach and education efforts. Website/webpage development is now a major focus for agencies that deal with large carnivore conflicts, with interactive links accessible to anyone in the world to garner information about safety in landscapes inhabited by carnivores. Social media have proven extremely effective in providing “virtual” safety workshops and community talk sessions to discuss ongoing issues and work being done to rectify those situations. Facebook Live™, Google Meetings™, and Zoom™ formats have evolved and their use and increased exponentially since the global Coronavirus pandemic of 2020–2022. Creative natural resource agencies took advantage of the amplified use of virtual meetings to continue interacting with an interested public, even when the ability to meet in-person was no longer an option. While there is no single format that provides the most effective outreach and education, a combination of multiple techniques can be beneficial. It is critical managers and educators know the stakeholders they are dealing with to determine the best method to reach their intended audience.

5.2 Producer Interaction and Communication

When dealing specifically with livestock depredation issues, it is critical that agency personnel and producers develop and maintain active communication channels and cooperative relationships to successfully mitigate problems as they develop. Fostering a trusting, face-to-face relationship based on consistency, honesty, and reliability between livestock producers and agencies when dealing with depredation is by far the most effective methodology for long-term, effective livestock depredation management (Fig. 24.2). Every state and provincial agency have programs to deal with livestock depredation, but many of these programs have subtle nuances that can be confusing to a producer when their operation crosses jurisdictional boundaries. Similarly, because managers must follow state/provincial statutes and commission regulations when verifying livestock losses, miscommunication can often result in anger and frustration for the producer, in particular when compensation is only given for confirmed depredation/damage from large carnivores (Fig. 24.2; Bruscino and Cleveland 2004; Thirgood et al. 2005; Morehouse et al. 2018). Contentious interactions often occur when livestock are killed by a large carnivore, because the toll on an individual’s ranch operation can be substantial and livestock producers want the situation remedied immediately. There will also always be instances where disagreement occurs between agency personnel verifying damage and the effected producers. Lethal removal of wolves, mountain lions, or bears is often controversial and can result in litigation and changes in agency policies (Slagle et al. 2017). As stressed before, these volatile situations illustrate why consistency is critical; telling a producer what they want to hear will only make things more difficult and can have a “snowball effect” in the future.

Fig. 24.2
A photograph of two men and dead livestock. They are observing the injuries of the dead livestock to check the cause of the death and rectify future damage to livestock.

When verifying cause of death and/or depredation, cooperation and communication with the producer(s) is critical to walk them through what may be observed as the entity responsible for verification. In situations of dead livestock, it is best to skin the animal throughout to look for diagnostic signs of depredation by species. In the case of injured livestock, working with the producer to verify suspected cause of injury will assist to rectify future damage. These data can contribute to potential damage compensation programs if applicable. Photo by Wyoming Game and Fish Department

Full size image

Therefore, an active damage management program should include everything from proactive conflict reduction measures to outreach and education programs to active on-the-ground conflict resolution (i.e., capture, relocation, removal). Furthermore, an agency that instills the importance of their damage program into its institutional knowledge and trains field personnel to conduct the program with understanding and professionalism is the best way to timely and effective conflict resolution programs (Bradley et al. 2005; Breck et al. 2011).

6 Large Carnivore Ecosystem Threats

Section 24.2 addressed the major anthropogenic factors that resulted in population declines of big game and large carnivores across North America during westward European settlement. Direct human persecution, indirect prey reductions, landscape conversion toward tilled agriculture, and urbanization negatively impacted wolves, mountain lions, and black and grizzly bears. Many of these historic impacts have been identified and addressed from a conservation/management perspective and large carnivores and other species of wildlife have responded positively (Jenks 2011; US Fish and Wildlife Service 2011, 2017b).

However, the greatest potential future threat to large carnivores and most wildlife species is the increasing loss and/or fragmentation of rangeland habitats due to subdivisions and other human developments (Lindenmayer and Fischer 2006). An often-overlooked aspect in the recovery of large carnivores has been retention of large tracts of open rangeland within landscape level ranching operations. Through maintenance of these open rangeland settings and adjacent forested habitats, longevity of large carnivores and their principal prey species have been restored. Continued retention of these vital areas, in conjunction with the regulated management and protection of core habitat(s) will be crucial to continued resurgence of all large carnivore species in western North America.

7 Large Carnivore Research and Management Needs

Increased research and monitoring lead to more accurate and accountable management plans. These plans, conveyed in a number of ways to the public and cooperating agencies, inform how biologists and livestock producers can assess and deal with large carnivore conflict and conserve species on the landscape through translocation, hunting, or other methods. Because there is great international scrutiny in how carnivores are managed, acquisition of accurate data and strict adherence to plan details is imperative when justifying management actions and harvest regimes (Hovardas 2018). Justification of management strategies and objectives using solid, defensible data and transparency maintains public trust and may belay critics against certain management practices (Martin et al. 2009; US Fish and Wildlife Service 2017b). When being questioned concerning particular management actions (such as lethal removal or no-action taken), reliance on science-based actions and open, frank communication can assist to refute criticism. A regimented approach can also be relayed to the public so there is a transparent understanding of why a particular choice was made.

Management plans and situational guidelines that include the data-driven approaches referenced throughout this chapter provide further foundation for agency reliability and also serve to refute perceived instances of unfounded liability and the possibility of future litigation. While it is impossible to accurately prognosticate the future of large carnivore management and conflict mitigation, it is safe to say that the issues managers and agencies are dealing with today will only increase in intensity and scrutiny. Human occupation of the land continues to increase as does interest in recreational activities on public lands that are in essence prime habitat for large carnivore species. Outreach and educational programs focused on proactive efforts to reduce conflict are the future of successful programs aimed to maintain large carnivores and human livelihoods in areas of overlap. The successful recovery, conservation, and management of wolves, mountain lions, and bears will continue, and therein lies the challenge. It is imperative that management agencies utilize data-driven management strategies and a proactive/reactive conflict management program to reduce conflict and maintain tolerance of large carnivores in rangeland settings.

The intricate interactions among intact carnivore guilds and multiple prey species in natural systems are just beginning to be examined (Griffin et al. 2011; Eaker et al. 2016). The evolving interactions between predators and prey in North America provides an abundance of research opportunities, and using more holistic long-term studies allows insight in ecological phenomena that are of key interest to multiple stakeholders. There is continued interest in the ecosystem role of carnivores and conversely there is keen scrutiny on predation impacts to prey populations, which are research needs throughout all areas where the species are sympatric with multiple prey species. When humans are included in the equation, overall comprehension of these dynamics is even less understood. There is increasing societal pressure to provide instantaneous solutions to problems involving large carnivores and many of the publics interested in these animals expect wildlife managers to be omniscient. Research and monitoring strategies have been designed in recent years to evaluate the interactions between this new norm of intact carnivore guilds (Atwood et al. 2009) and their potential impacts to wild and domestic prey (Barber-Meyer et al. 2008), interspecific carnivore interactions (Bartnick et al. 2013; Elbroch et al. 2015) and inclusion of human population dynamics. Agency personnel often hear the refrain, “they were here first” (referring to wolves, mountain lions, and bears) from individuals or advocacy groups that demand a hands-off approach for native carnivore species. Nevertheless, a more pragmatic approach is to consider humans as integral to the ecosystems we share with these species, thus facilitating the concept of continued cohabitation of western landscapes for all species wild, domestic, and human into the future.

8 Conclusion

During the last 4–5 decades, large carnivores have increased in abundance and distribution following more than a century of determined effort to exterminate them. In this chapter, we have presented a brief overview of ways people may gain a better understanding of the ecology and management of wolves, mountain lions, and bears and outlined a number of methods to reduce conflict between these species and people in areas where they overlap. It is impossible to eliminate all conflict between humans and large carnivores because of the continuing intrusion of humans into habitats occupied by large carnivores, and concurrent expansion of these species into rangeland settings dominated by human use (Wilson et al. 2005; Wells et al. 2019). Additionally, outdoor recreationists are increasing their use of public lands, especially in areas that are remote rangeland and wilderness habitats, placing this segment of the public in direct conflict with both existing livestock operations and large carnivore populations. Communication and collaboration among multiple user groups must continue to improve understanding of the varied and sometimes conflicting needs and desires of these groups while recreating or working within rangeland habitats inhabited by large carnivores. Only by combining the dedication and knowledge of wildlife management agencies with the passion of people who live, work, and/or recreate in rangeland settings can a sympatric land use ethic be realized. The continued persistence or these charismatic megafauna depend on human tolerance, understanding, and acceptance among all resource users—now more than ever.