In this article the most essential scientific findings have been compiled that anybody (including national and global citizens) involved in wolf management policy making should be familiar with.
The publication titles will be supplemented with brief outlines of the essential discoveries and some explanations provided in the studies or added by the author of this article.
The list is not completed and more publications will be added to it over time.
The publications will be classified in the following categories:
- Ecosystem roles (prey regulation, trophic cascades etc.);
- Other important services (eco-tourism etc.);
- Tolerance promotion and media;
- Reasons for non-lethal wolf management;
- Coexistence (conflict management).
The publications have not been listed in order of importance but in order of publication year (followed by title in alphabetical order if publication year is the same).
An additional article (Grey Wolf (Canis lupus), a Keystone, Umbrella Species) has been published that reviews our knowledge of wolves as a keystone species regarding their ecosystem roles resulting in trophic cascades and landscape of fear phenomena.
ECOSYSTEM ROLES
Trophic rewilding can expand natural climate solutions (Schmitz, O.J. et al., 2023)
The study reviews the potential of specific (keystone) wild species recovery and conservations plans to mitigate climate change (respective to the carbon sequestration).
Grey wolf is one of the 9 species that can significantly improve carbon sequestration (specifically, in boreal forest ecosystems).
‘Trophic rewilding’ of these 9 wild species combined could contribute to sequestring and storing of ca. 6.41 gigatons of CO₂ annually which constitutes approximately 95% of the amount needed to be removed from the atmosphere annually in order to achieve the Paris Agreement resolutions (keeping the global warming under 1.5 ℃).
In order to ensure the global warming threshold of 1.5 ℃, it would be necessary to reduce future emissions but also to remove approximately 500 gigatons of CO₂ from the atmosphere by 2100.
‘Trophic rewilding’(restoration of species and genera such as grey wolves, sea otters, whales, sharks, African forest elephants, marine fish, wildebeest, musk oxen, American bison that play a key role in trophic chains impacting crucial processes in ecosystems) would accelerate the removal rates and the aforementioned 500 gigatons of CO₂ could be removed in 35 years (as opposed to 77 years).
The grey wolf impact on the carbon cycle has been assessed (and quantified in a preliminary manner) in the US study, ‘Effects of grey wolf-induced trophic cascades on ecosystem carbon cycling’ (Wilmers, C.C. & Schmitz, O.J., 2016) which has established that grey wolves would benefit net productivity in boreal forest ecosystems where they prey on browsers (tree-eating ungulates), e.g., moose.
The increase in carbon sequestration levels in boreal ecosystems is achieved through the release of tree growth and establishment as well as through prevention of tree mortality and the reduce in moose respiration rates.
Trees, in turn, ensure permanent storage of carbon in the forest soils and the woody biomass.
However, there could be other indirect influences exerted by wolves on carbon sequestration rates.
For example, study by Wohl, E., 2013 attempts to quantify beaver impacts on carbon storage through ecosystem engineering activities.
The author concludes that active beaver colonies could contribute as much as 23% of landscape total carbon storage rates and that, for example, approximately half of the organic carbon stored in the sediment layers of soils in east Rocky Mountain National Park might have been accumulated, historically, due to beaver activities.
Meanwhile, beaver populations have declined in many places as a result of competition with elk released from predation pressure that overgraze on riparian vegetation reducing habitat availability for the beavers.
Regulation of elk grazing by wolves facilitates beaver population recovery and activities thereby promoting carbon storage rates on a potentially highly significant level.
Wolf-moose and wolf-elk-beaver interactions are merely two examples of a possibly vast array of carbon sequestration-related ecosystem processes that attest to the role of the grey wolf in mitigating climate change.
The Role of Wolves in Regulating a Chronic, Non-Communicable Disease, Osteoarthritis in Prey Populations (Hoy, S.R. et al., 2022)
While wolves can control disease transmission and prevalence rates during specific outbreaks (which can be as long as the pathogen or the parasite survives in the ecosystem), this study discusses how wolves might reduce disease prevalence in the long term (between generations – through genetic selection), potentially, creating a prey population that is no longer prone to genetically inherited afflictions.
For example, while wolves mostly prey on juvenile and senior moose, wolves also show a tendency to prey on osteoarthritis-affected adult moose of breeding age.
Usually, the breeding individuals of the prey population are less affected by wolf predation which is beneficial because these individuals repopulate the communities.
Wolves, however, appear to be removing unhealthy breeding individuals.
In the case of osteoarthritis which is a genetically-transmitted disease and which can manifest in non-senior individuals if such individuals carry the ‘bad gene’, the predation by wolves on adult, breeding individuals exhibiting lower fitness due to genetically inherited condition causes a reduction in disease prevalence in further moose generations because individuals who have the ‘bad gene’ are less likely to breed (they have been killed by wolves before they have completed their breeding life stage) and therefore less likely to pass the condition on to the next generations.
Such genetic manipulations might bring about healthier moose populations with the ‘bad gene’ prevalence reduced in the population’s gene pool or even eliminated eventually.
Evaluation of the Presence of ASFV in Wolf Feces Collected from Areas in Poland with ASFV Persistence (Szewczyk, M. et al., 2021)
The study conducted in Poland discusses the beneficial role that wolves play with regard to reduction of the transmission and prevalence rates of African swine fever (ASF) that is caused by a DNA virus (ASFV), that affects both wild suids (wild boar, Sus scrofa) and domestic pigs (Sus scrofa domesticus) and that can be transmitted between wild and domesticated populations.
Upon reported outbreaks, on national level, millions of pigs have been culled resulting in enormous economic losses.
For example, during a two year period since the first outbreak in China (2018 – 2020), ASF spread to at least 8 countries in Asia and more than 5 million domestic pigs were culled (> 10% of the total pig population in China, Mongolia and Vietnam; potentially 30 – 60% loss of pig stocks in China, specifically) (Gaudreault, N.N. et al., 2020).
The losses in Europe have not fallen behind.
It is also important to contain the disease in order to prevent its spreading to ASF-free regions.
Therefore, it is of great interest that wolves can reduce the transmission and prevalence rates of ASFV in wild boar populations.
Wolves consume the wild boar carcasses infected with ASFV that have suffered mortality due to the virus or due to other causes (e.g., winter condition impact escalated by weakened immunity).
8 out of 9 wild boar carcasses that wolves fed on in the study area were infected with the ASF virus while all of the wolf feces sampled near the scavenging sites as well as within the ASF zones, were ASFV-negative.
Thus, it can be concluded that wolves do not act as infection transmission vectors but instead the virus does not survive the wolf digestion process and wolves convert the infected biomass into uninfected fecal matter which is then returned to the environment without the pathogen content.
This is of particular importance because the virus can persist in the environment for at least 280 days (contained within the infected biomass and transmitted upon contact, e.g., upon scavenging by wild boar on the perished wild boar carcass).
Thereby, wolves can reduce both infection prevalence and infection transmission rates.
Moreover, wild boar constitute a dangerous prey.
Wolves in most regions are known to only scavenge on wild boar or to prey upon wild boar highly selectively to lower chances of injury by the formidable ungulate.
Wolves would be likelier to attack juveniles or adults that are in a considerably weakened state.
Both aforementioned groups hold the most potential of being ASFV-positive and the selective feeding by wolves can remove precisely the infected individuals from the wild boar population.
Additionally, wolf tracking for scientific purposes can assist in a timely detection of wild boar carcasses and their subsequent removal from the environment by humans.
The removal of wild boar carcasses is one of the methods applied by governments to ensure reduction in disease prevalence.
Wolves can be more effective at locating wild boar carcasses than humans or software-run simulations are.
If wolves detect the presence of the carcass comparatively briefly after the demise of the individual, scientists can discover the carcass through the radio-tracking of the wolf activities and they can request its removal from the environment before significant transmission risk has occurred.
Spatial compartmentalization: A nonlethal predator mechanism to reduce parasite transmission between prey species (Oliveira-Santos, L.G.R. et al., 2021)
Wolves are the long-term health agents of the ecosystem. It is one of the most essential services that wolves can provide.
Wolves can reduce disease rates by limiting the encounter rates between prey communities and by limiting prey group size and prey interactions (disease transmission opportunities) as well as by removing and consuming unhealthy individuals (in which task wolves are aided by scavengers).
Additionally, wolves regulate disease dynamics by altering genetics through removing individuals that are genetically predisposed to disease.
This particular research looks at the reduction of disease transmission (brainworm parasite) between white-tailed deer and moose.
While wolves remove some of the prey species individuals (wolves do not eat much – they eat 2 – 3 times per week), the disease rate reduction does not predominantly lie with the decrease in prey numbers.
Instead, wolves change how wild prey moves and acts (inducing host-species segregation and thereby reducing contact rates between hosts) thus assisting in ensuring the long- term well-being of the prey species.
It means that, under wolf predation pressure, moose and deer demonstrate decreased spatial overlap and the parasite cannot become transmitted as frequently from deer to moose benefiting moose survival and moose population fitness.
The segregation in the study system was driven by changes in habitat selection in moose and deer and such changes have been reported for other prey species, as well (elk, caribou) in different prey community systems.
While killing prey, in the long-term, wolves do not deplete the prey species population and might actually sustain it and improve its fitness (unless there are external factors that affect the prey-predator dynamics such as massive habitat loss or severe habitat fragmentation).
Much of the environmental health is achieved not through direct predation but through wolf impact on prey movement and behaviour (e.g., by creating a landscape of fear).
Wolves are not agents of death but rather agents of health.
They inflict only as much death (and fear) as is needed to ensure that in the long run, the death rates are kept as low as possible.
Wolves contribute to disease control in a multi-host system (Tanner, E. et al., 2019)
The study discusses wolf impact on prey species health rates and even implies that wolves might help regulate some diseases that affect livestock.
This research has been conducted in Europe and its results suggest that wolves can reduce bovine tuberculosis infection prevalence rates in wild boar populations.
Meanwhile, wild boar can act as bTB transmission agents to livestock, therefore, disease reduction in wild boar is also potentially beneficial for farmers.
The disease rate reduction is not merely a consequence of the prey population abundance (wild boar numbers) reduction (wild boar numbers in the study area remained relatively unchanged and even slightly grew while the disease rates dropped).
It means that the disease control mechanism does not involve actual killing of wild boar in great numbers but rather affecting the prey species behaviour through the wolf presence in the area.
It is likely that increased mortality due to predation is compensated for by reduced mortality due to disease.
With the wolves around, the infection transmission rates decreased (more than four-fold).
The efficiency of disease rate reduction is also related to prey selectivity by wolves.
Wild boar are not an easy prey (the large size can make it formidable) and wolves select individuals that are very young (piglets) or severely weakened.
Both piglets and weakened individuals are the likeliest pathogen-holders.
Thereby selective predation by wolves results in removing the highest risk individuals from the environment.
Disease rates can become significantly reduced without reducing the number of wild boar population because the diseased individuals are selectively removed (rather than simply removing a large proportion of all individuals in the population).
The authors also attempted to quantify the potential economic benefits due to wolf presence (through the mechanism of disease control).
For example, in Asturias (Spain), compensations paid to farmers due to wolf attacks on their livestock are 4 times less costly than bTB control costs.
Meanwhile, in areas without wolves, the bTB rates detected in cattle can be 5 times higher than in areas where wolves are present.
The role of predation in disease control: A comparison of selective and nonselective removal on prion disease dynamics in deer (Wild, M.A. et al., 2011)
Wolves as coursing predators (and other larger predators but to a lesser extent) can assist in limiting the spread of the deadly chronic wasting disease that affects elk and other cervids in North America (although it has also been detected in Europe as mainly a genetically-transmitted (not environmentally-transmitted form as well as in Asia) and that potentially might be transmitted to humans.
The findings serve to also illuminate wolf potential in reducing the infection rates and prevalence in the case of CWD but also in the case of other such deadly or pervasive diseases.
Wolves are more effective than, e.g., ambush predators or human hunters in reducing CWD transmission rates through highly selective (precision targeted) removal of infected individuals as well as through removal of infected individuals at earlier stages of infection (who thereby have less time to spread the disease).
Chronic wasting disease infection is present in an individual before it manifests visibly which is why human hunters are not as able as wolves are to identify infected individuals in early stages of the disease.
The aforementioned detection ability (selectivity) by wolves is also relevant when the disease prevalence rate has fallen and the proportion of infected individuals in the population is, once again, lower which is why removal of infected individuals becomes more subtle and non-random (it is no longer productive to remove large numbers of individuals to contain the transmission rates).
The detection and evaluation of the possible victim’s state of fitness is more efficient in wolves due to their cursorial predation strategy (compared to ambush predators, e.g., cougars).
Additionally, wolves can ‘cleanse’ the infected cervid biomass.
Most prion pathogens do no survive the process of passing through the wolf digestive tract and thus the pathogens do not persist in the environment – the ungulate biomass becomes ‘recycled’ by the wolves consuming an infected product and returning a pathogen-free product.
Prion disease does not affect canids and the digestion of the infected meat implies no risk to the wolf.
The simulation models developed within the research suggest that wolves could curb the spreading of the infection within decades and eliminate it within a century.
It is also highly possible that such infections can only acquire massive rates of transmission and prevalence in ungulate populations that are not regulated by large predators.
Had the wolves not been eliminated from many regions of the US (or severely reduced in their populations), it is likely that CWD would never even had emerged at all or would never had acquired rates worthy of our notice and concern.
Thereby, it is important to support healthy, large and stable wolf populations in order to prevent the very emergence of similar infections in the future.
Gray Wolves as Climate Change Buffers in Yellowstone (Wilmers, C.C. & Getz, W.M., 2005)
The study has been conducted in the Yellowstone National Park, US but its conclusions are not limited to YNP.
The study assesses how wolf predatory activities might benefit the scavenger communities in the face of the climate change (including, for example, such iconic species as gold eagle, bald eagle, wolverine but also, bears, ravens, foxes, coyotes etc.).
Climate change implies that the winters will be shorter and warmer.
Herbivore mortality might become overall reduced or, at least, the late winter mortality rates may become lower because snow will pose fewer obstacles and plants might regenerate earlier in spring providing the herbivores with an opportunity to recover from the cold season’s strain.
This result in decreased carrion availability bearing the subsequent impact on the scavenging communities.
Moreover, carrion availability would be reduced later in the winter – at a period in species’ annual cycle which is essential, for example, for brown bears as they emerge after hibernation but also for other species that need to reach an adequate level of fitness in order to reproduce and to give birth to healthy litters of healthy young.
Carrion availability in late winter can determine reproductive success and, therefore, population sustainability in many species.
Wolf presence allows to distribute the amount of carrion available to the prey species more evenly throughout the cold season.
The scavenging guild is extremely important because scavengers ensure natural control of many pest populations.
They also remove dead flesh from the environment which reduces disease and parasite transmission rates and which contributes to nutrient cycling.
Without scavengers, our nature (and society) would suffer increased pest and pathogen outbreaks.
In temperate regions, wolves are a key player in ensuring the perseverance of the scavenging communities under the conditions of climate change.
OTHER SERVICES
Wolves make roadways safer, generating large economic returns to predator conservation (Raynor, J.L. et al., 2021)
Research in Wisconsin has attempted to quantify some of the economic benefits that can be gained through conserving the local wolf population.
Wolves are capable of affecting their prey movement in ways that reduce the rates of deer-vehicle collisions (by as much as 24%).
This is not achieved through killing prey (reducing prey species numbers) but rather through changing the prey migration patterns (prey behaviour).
The scientists attempt to show that losses due to wolf depredation on livestock can be significantly smaller than financial gains due to wolf presence in the area.
For example, wolf predation on livestock in Wisconsin might cost $174.000 annually while deer-vehicle collision damage may reach as much as $200 million per year.
A reduction by 24% would allow to save approximately $48 million which is a much bigger gain than the compensations for the lost livestock.
PROMOTING TOLERANCE
The positive experience of encountering wolves in the wild (Arbieu, U. et al., 2020)
The study has been conducted in Germany with the objective to determine the rates of positive / neutral / negative wolf encounter experiences shared by the German public.
It also addressed the issue of what determines the nature of such experiences.
The majority of respondents (almost 60%) reported positive wolf encounter experiences followed by neutral experiences (approximately 25%), and only a fraction of the respondents considered their experience negative (approximately 15%).
It was further confirmed that people who had experienced positive encounters with wolves also attested to greater tolerance to living in close vicinity to wolves (people were willing to reside within approximately 35 km from wolf territories).
If positive experience is the foundation of tolerance, it is important to study the reasons behind positive vs. neutral vs. negative experiences.
Upon discovering the factors that increase the likelihood of having a positive experience with wolves, these same factors can be considered as a strategy to promote tolerance (because, as stated before, tolerance has been proven dependent on the nature of the experience).
The findings suggested that increase in the probability of having positive wolf encounters was rooted in education.
People who were more knowledgeable on wolf ecology and wolf population status in their country, were also more likely to report positive experiences with wolves.
Prior knowledge of wolves is the essential determinant of emotional attitudes formed during encounters.
The positive encounters alongside the growing of knowledge base could also be manipulated through offering experience in a controlled, safe environment (e.g., education programmes and visits to conservation centres with exposure to ambassador animals) because the positive encounter rate was not affected by the setting of the experience (encounters in the wild, in Germany vs. encounters in the wild, abroad, vs. encounters in captivity).
The study, thereby, demonstrates that education is a powerful and efficient tool to reduce fear, to promote tolerance and to ensure positive experiences in encounters between wolves and people.
Blood does not buy goodwill: allowing culling increases poaching of a large carnivore (Chapron, G. & Treves, A., 2016)
The study challenges the popular assumption that legalized wolf culls might promote general tolerance in the society toward wolf presence.
Scientists reveal that the assumption ‘lethally managed wolves are better tolerated wolves’ cannot be considered founded and that any legal wolf killings (licensed culls or federal trapping, ‘problem wolf’ removal etc.) give way to greater poaching rates (which can, in turn, endanger other species, including, for example, pets and protected species) as well as heightened hostility toward wolves in the society.
Therefore, we cannot rely on ‘legal killing’ as a way to appease the public and to ensure better attitudes toward wolves.
Contrary to unscientific claims, legal killing only leads to increased rates of illegal killing as well as reduced tolerance.
Instead, education and financial assistance in establishing preventive wolf-livestock conflict risk aversion measures should be the top policy.
Conflict misleads large carnivore management and conservation: brown bears and wolves (Fernández-Gil, A. et al., 2016)
This study has been conducted in Spain and it has revealed the disproportionate rates of wolf-related conflict representation on media (relative to media coverage of, e.g., brown bear caused-damage as well as relative to actual conflict rates and actual wolf demographics).
The publication also discusses how the misrepresentation of the wolves on media affects public opinion as well as the subsequent wolf management policies.
In northwest Spain, the brown bear and the grey wolf are the two large predators that cause most human-wildlife conflict incidents and that are subject to the greatest controversy.
It might also be of importance that (during the study period) the bear was legally protected while the wolf was not.
As a result, public opinion toward bears was manifested mainly through state actions while that toward wolves could also take a more personal form.
The study found that compensations for wolf-caused damage were 5 times higher than compensations for bear-caused damage.
However, it must be noted that bears in the study area mostly destroy beehives while wolves kill livestock.
Dead livestock warrant greater compensations than destroyed beehives, therefore, the difference in payment rates does not necessarily reflect the difference in conflict rates.
One destroyed beehive costs less in damage compensations than one depredated livestock unit.
Thus, for example, a single incident of damage caused by bears or caused by wolves would result in different payment rates.
If bear damage has cost altogether less than wolf damage, is does not necessarily follow that bears have caused substantially fewer conflicts.
However, wolves did cause more damage than bears did and, for the sake of simplifying the argument, we could even assume that wolves caused 5 times more damage than bears did (which was not exactly so).
Meanwhile, the media coverage of wolf-related conflicts was 30 times higher than media coverage of bear-caused conflicts.
Wolves received a disproportionate rate of negative media coverage compared to bears.
Moreover, increase in media coverage of the conflict incidents was followed by an increase in calls by public for the government to organize wolf culls.
Hence, the wolf culling rates did not follow the actual rates of damage caused by wolves but exceeded it up to 6 times because the wolf culling rates were based on media coverage rates which were disproportionate to conflict rates.
The media coverage and the subsequent public calls for culls did not follow the actual wolf population dynamics, either.
Increase in demand for culls and increase in cull rates were not correlated with a scientifically (factually) established increase in the wolf population.
It only followed the increase in media hype.
It can be concluded that the number of wolves culled at any particular period was not reflective of the wolf populations count, nor conflict rates and the damage done.
Instead it was reflective of the public attitude which was formed and influenced by the exaggerated media coverage which was disproportionate to conflict rates and wolf population demographics.
A loop was created where the reality was omitted and wolf management relied not on facts and numbers but rather on hype and unadvised, unsubstantiated attitudes.
Media tended to over-represent the wolf damage and the public simply followed these over-representations by calling for culls.
As a result, wolf culls were conducted in an unscientific, unreasonable and unjust manner.
REASONS FOR NON-LETHAL WOLF MANAGEMENT
Human-caused mortality triggers pack instability in gray wolves (Cassidy, K.A. et al., 2023)
Human impact (legal hunting, poaching, traffic accidents etc.) is frequently assessed on a population level (e.g., regional scale).
The publication demonstrates that assessments of such (large) scope might fail to advise on more subtle implications and adverse effect that human impact exerts on wolf populations and that can only be evaluated on a finer scale (e.g., social group level).
That the regional (or national) wolf population might not change dramatically due to, for example, legal hunting unless the hunting rates exceed certain limits.
Wolves appear to be replenishing their numbers and recolonizing the territories vacated by the removed individuals and the disrupted packs.
On the social group level, meanwhile, the impacts may be severe and detrimental leading to a wolf population which is ‘numerous enough’ but which is not healthy and stable, nor it is yielding the environmental benefits that wolves provide as keystone species.
Also, such disrupted populations might increase human-wildlife conflict rates.
Wolves are social animals that rely on their packmates in cooperative breeding, cooperative hunting, cooperative territorial behaviour etc.
Wolf ecosystem functions and services cannot be performed outside of the wolf social group context and long-term social groups are the units that ensure balance between the local wolf populations and their prey species as well as enable the wolves to carry out their roles in the environment.
Additionally, wolf social stability determines the wolf population long-term viability (including genetic diversity and persistence).
Thus, while on a regional (e.g., state) level human-caused mortality might not appear to overly impact the total number of the wolves in the area, on a social group level these effects are much greater and highly disruptive as well as spilling over into the environmental interactions.
Human-caused mortality of any wolf that belonged to a specific pack decreases the odds of the particular pack’s persistence to the end of the biological year by 27%.
Meanwhile, human-caused mortality of a breeding wolf (pack leader) decreases the aforementioned odds by 73%.
Human-caused mortality of any wolf in the pack decreases the odds of the particular pack’s reproduction in the following year by 22%.
Human-caused mortality of a breeding wolf (pack leader) decreases the odds of the pack’s reproduction the following year by 49%.
These findings demonstrate that human-caused mortality (including legal hunting) can lead to pack disruption and the inability of the established packs to breed.
This causes social instability which limits the capacity of the wolves to enact the regulatory services in their ecosystem.
Additionally, other research (e.g., Molnar, B. et al., 2015; Wirobski, G. et al., 2023) shows that wolf’s physical and psychological wellbeing is dependent on stable social organization and disruption of social structures can lead to emotional distress (psychological harm) but also to reduced fitness and immunity (physical harm).
It is worth noting that the long-term gathering of the data applied in this research has been performed in US National Parks which are supposedly sheltered (to a greater extent) from human impact.
Therefore, human impact outside of such protected areas might prove even greater.
Similar behavioral but different endocrine responses to conspecific interactions in hand-raised wolves and dogs (Wirobski, G. et al., 2023)
Wolf Science Centre researcher group in Austria has compared wolf and dog behaviour as well as hormonal metabolite (oxytocin and glucocorticoid) concentrations in wolf and dog urine after exposure to specific experimental conditions:
- control conditions, i.e., an emotionally and behaviourally neutral situation;
- territory patrolling (defense) simulation;
- elicited chorus howling;
- spontaneous chorus or solo howling;
- temporal separation from group members.
No significant differences were observed between wolf and dog behavioural responses.
The hormonal metabolite concentrations, meanwhile, were contrasting in both species.
Wolves demonstrated higher oxytocin production levels upon conditions of engaging in synchronized behaviour with other pack members (during territorial patrolling), compared to dogs.
Oxytocins are hormonal metabolites that encourage group bonding as well as behavioural coordination and consensual cooperation within group dynamics.
Behavioural coordination and group cohesion are of crucial importance in wolves’ social ecology.
The survival of an individual as well as the survival of the group depend on the ability to perform cooperative hunting, cooperative defense and cooperative breeding (raising of the young).
Dog social ecology does not rely on group cohesion as greatly.
Free-ranging dogs may form social groups that defend a common territory.
However, cooperative breeding and cooperative foraging is not characteristic of free-ranging dog social units.
Free-ranging dog intergroup conflicts are rarely as lethal as those observed in wolf populations where intergroup strife is often the leading natural mortality factor.
Wolves also demonstrated higher glucocorticoid concentrations during territorial defense simulation as well as during temporal separation from group members.
Wolves moved more during separation conditions (active attempts at escaping and following the other pack members).
Additionally, wolves howled for longer duration.
Dogs were more inclined to passively wait for the return of the other group members although they whined more often than wolves did.
Even though the behavioural (externally observed) differences were not pronounced, the emotional, psychological and physiological state of the wolves (expressed through chemical analysis of wolf urine) attested to higher stress levels (glucocorticoid = ‘stress hormone’ production) during territorial defense and during separation.
Staying together with the pack, cooperating and reuniting with the pack members as well as being able to integrate oneself into the pack’s social structure appears to be of great importance in the wolf species.
These are states that evoke responses which bear significant effects on the wolf’s emotional, psychological and physiological wellbeing and, therefore, on wolf’s fitness.
Oxytocin ensures pleasurable experiences within the context of socializing.
Glucorticoid is produced and released during situations of stress and anxiety.
The study attests to the detrimental effects of separation from pack members on both psychological and physiological level while the opportunity to spend time with the pack and to engage in cohesive cooperation promotes happiness in wolves.
Lethal control measures (including legal hunting and culling) disrupt pack social structure and social group stability.
Groups break up or they become restructured – the former level of cohesion is lost or reduced.
Thereby, lethal control measures bear negative effects on wolf psychology and physiology as well as deny the individual the experience of positive emotions and security.
Separation from the pack, pack break-ups and social instability cause direct stress response in wolf individuals (which on long-term basis can translate into reproductive and health-related fitness risks that affect the entire population).
Loss of pack cohesion and coordination, on the other hand, limits the potential of attaining regular (but essential) happiness levels.
Efficacy of killing large carnivores to enhance moose harvests: New insights from a long-term view (Miller, S.D. et al., 2022)
In this study, nearly 4 decades of accumulated data were analyzed to evaluate the claims that reduced large predator (wolf, brown bear, black bear) populations in Alaska should lead to increased moose population rates which become reflected in increased moose harvest rates.
That is to say, the common assumption that killing large predators results in greater abundance of moose for hunting by humans was tested.
No such correlations between predator hunting and moose hunting could be identified and the removal rates of large predators did not result in increased moose harvests not in the following year, nor when accounted for potential lag-effects.
Therefore, lethal large predator control is not a viable method of maintaining moose populations (including for moose species conservation purposes).
Environmental and intrinsic correlates of stress in free-ranging wolves (Molnar, B. et al., 2015)
The united research covering wolf populations in Europe (Abruzzo, Italy and Mercantour, France) as well as in the US (Yellowstone) demonstrates the impact of social disruption and loss of pack members (especially, the breeding pair or one of the dominant breeding individuals) on cortisol levels (stress hormone metabolites) in free-ranging (wild) wolf faeces.
Increased cortisol levels were found in wolf packs that had recently suffered loss of pack members and/or in which the breeding pair’s bond had been disrupted.
This indicates that social instability and bereavement affects wolf physiology.
Increased cortisol metabolite concentrations in the long term can lead to negative effects in the population health and reproductive output.
Such effects have not been studied, specifically, in wild wolf populations but general wildlife research suggests,
‘In accordance with this, previous studies of free-ranging social mammals and birds report a negative relationship between GCs levels and fitness,’
and
‘Besides an immunosuppressive effect favoring pathogenic infections, chronic high cortisol concentrations can cause neuronal cell death, muscle and bone atrophy, poor wound healing, as well as inhibition of growth and reproduction.’
For example, the metabolite concentrations were considerably higher in Abruzzo, Italy than in France or the US.
Abruzzo wolf population was also characterized by a greater endoparasite infection rate.
While endoparasite load may by itself increase cortisol levels, the causality might also be reversed, i.e. the immunity (parasite resistance) might have been weakened due to increased cortisol metabolites that result after the trauma.
Such increased cortisol levels can lead to a greater pathogen and parasite infection risk.
Social and environmental stress (e.g., social instability of the wolf packs but also other disturbances) can increase the endoparasite load as well as negatively affect the wolf population’s immune reactions.
By disrupting wolf social group structure and by killing wolf pack members, not only is the wolf psychological wellbeing threatened but also the wolf population’s physical fitness (health, persistence) is compromised through weakened immunity, increased susceptibility to disease or other additional/stochastic stress factors as well as reduced reproductive potential that impacts the recovery potential and the sustainability of the population.
What is an apex predator? (Wallach, A.D. et al., 2015)
The study is most essential in guiding our large predator management decisions.
The research proposes a recently developed insight that apex (large, top-trophic-level) predator species are capable of self-regulating their own populations through social and biological mechanisms.
Namely, there are predators (usually, large predators above a certain weight threshold) that do not need external control (e.g., lethal management) in order not to exhaust their resources and not to overpopulate their range.
Most animals (herbivores, small mammals, mesopredators) rely on external control mechanisms, for example, top-down regulation (predation) to maintain healthy population numbers that do not exceed the carrying capacity of their range.
There are, however, species of large predators that do not need such regulation ‘from outside’ and they are capable of regulating their own numbers through biological and social mechanisms (self-regulation).
The biological mechanisms include, for example, small litter size and extended parental care (fewer babies are born and they are taken care of for a longer time which means that there are fewer young individuals in the population who also develop slowly until the next litter is born).
Frequently, apex predators exhibit what is called ‘slow life histories’.
Compared to numerous other species that can produce several litters per annual reproductive season, apex predators give birth to only one litter per year (e.g., wolves) or even per several years (e.g., bears).
Additionally, large predators (including wolves) must establish and protect large territories in order to ensure the meeting of their energy demands.
Often, the larger the carnivore, the larger its territory (to incorporate the necessary prey numbers).
The sparse density due to exploitation of limited and scattered resources (prey) is in itself a population regulatory mechanism.
These territories are defended against conspecifics (other wolves) and used almost exclusively (with the exception of occasional intrusions by neighbours or floaters) by the social group.
For example, a wolf pack territory can range over 50 – 1000 square miles (130 – 2600 km2) and within this territory, only a specific, limited group of wolves will reside (~ 4 – 6 wolves; from 2 to > 10).
The forming of small social groups and the holding of large territories as well as the protecting of their territories against other wolves ensures that the regional wolf population will not become too dense.
Territory size is influenced by latitude and prey density.
At higher latitudes, territories become larger while they become smaller with reduced prey density (fewer prey).
For example, research in Białowieża Primeval Forest, Poland (Jędrzejewski, W. et al., 2007) has given local pack sizes of 3 – 8 wolves and local territory sizes average of 201 km2 (in a highly optimal protected forest environment with 5 wild ungulate species available which should result in considerably smaller territory sizes).
8 wolves per 201 km2 would constitute a high density (comparative to other global wolf populations with exception of those that only prey on rodents or mainly utilize human garbage resources).
If all the forests in Poland had contiguous wolf populations (which they have not) with such high density rates as observed in the pristine, highly suitable habitats of Białowieża, Poland would have around 3735 wolves and if this was converted to a proportion of the entire Poland state territory, there would be 0.01 wolves per every km2 of Poland or one wolf per every 100 km2 (which, of course, is an arbitrary number because wolves would be concentrated in forested habitats).
Or, to make the comparison more fun, there would be about 5 wolves per territory of the size of Warsaw.
There are other mechanisms that limit wolf reproduction rates and these mechanisms are social in nature (territory protection against conspecifics, however, is also a social mechanism).
For example, in the wolf group – not all wolves will breed.
If all wolves bred in the social group, we would have far greater wolf densities.
Usually, in one social group (family, pack) only two individuals will breed (the breeding male and the breeding female who are most often the parents of the wolf group).
The rest of the adult individuals are frequently capable of breeding but the social mechanisms within the wolf species limit their actual breeding and prevent them from producing their own offspring.
The non-dominant (subordinate) adult wolves that stay in their family pack (up to 1 – 3 years or longer), will normally not breed while the breeding pair is alive but they will invest their energy in providing for the breeding pair’s offspring that is normally related to them (siblings or nephews/nieces).
That way, only the breeding pair will produce litter (pups).
Instead of, e.g., 4 pack females breeding on a given territory and producing, on average, 4 – 7 pups each (totalling 16 – 28 pups), only 1 female will breed and only 4 – 7 pups will be produced that will mainly remain with the family until their own independence and dispersal (often substituting older pack members as they disperse or die).
These are some of the population self-regulation mechanisms and all of them (both biological and social) depend on wolf social organization and pack stability.
For example, if a pack cannot hold a territory, this might result in pack break-up and formation of smaller units which all have their breeding pairs.
As a result, the local wolf density would increase, at least, temporarily.
If the lethal management is permanent, wolf density increase might also become permanent (through repeated population patterns).
For example, hunted populations, as stated before, tend to form smaller groups and in order to survive (to be able to hunt down large prey), these small groups need to produce more pups to quickly grow the pack number to a sufficient level.
Therefore, even if the given pack remains intact, more females might be allowed to breed in the pack to replenish its numbers that are necessary both in cooperative foraging and defense.
As a result of lethal management, there might be a greater number of packs in the region that hold smaller territories and that produce a larger number of offspring in any given territory (as compared to non-persecuted circumstance).
Paradoxically, lethal management with the purpose of reducing wolf densities might lead to increased wolf densities.
To put it concisely, wolves do not need to be managed lethally in order to maintain sparse populations and not to overexploit their resources (unless they are severely restricted in access to wild habitat and wild prey).
Wolf populations have their own biological and social self-regulation mechanisms that ensure sparse residency.
Heavily hunted wolves have higher stress and reproductive steroids than wolves with lower hunting pressure (Bryan, H.M. et al., 2014)
The study by Bryan, H.M. et al., 2014 has analyzed stress and reproductive hormones in the hair samples of two wolf populations in Canada.
The tundra-taiga population was heavily hunted while the boreal forest population experienced considerably lower rates of hunting pressure.
A control group was also selected in the boreal forest ecosystem to account for possible habitat differences in the boreal population target group (that could affect hormonal production).
In hair, hormones are incorporated during the growth period (early spring to autumn) therefore the analysis attested to hormonal levels during these seasons and not during winter when the hair ceases growing before spring moult.
It was discovered that progesterone, testosterone and cortisol concentrations were higher in the tundra-wolves.
Progesterone in female wolves is attributed to increased reproductive effort which is the result of social disruption and the necessity of the survivors to ‘replenish’ the area (as explicitly expected by wolf policy makers in hunting regions).
However, constantly high progesterone production can lead to adverse fitness effects reducing the surviving female’s overall health (e.g., compromised immunity), lifetime reproductive success and wellbeing.
The socially disrupted tundra-taiga wolf groups could have several breeders and multiple litters per pack.
Such breeding activity has been at least partly caused by social instability and it may lead to altered social and demographic dynamics (increased wolf density and energy demands under the conditions of reduced pack efficiency due to disrupted pack cohesion, loss of experienced individuals etc.).
Higher testosterone in tundra-taiga males was not the result of hormonal production during the breeding season because breeding occurs in winter when the hair growth has stopped.
Accordingly, these hormonal levels were also likely due to social instability and the consequent territorial conflicts between the wolf groups and between wolf packs and floaters (roaming individuals or roaming groups).
Disrupted wolf packs can disperse or lose parts of their territories.
The lone wolves or the reduced groups begin roaming through established pack territories, acquiring food resources that belong to another pack’s summer home range (tundra-taiga wolves do not establish year-round territories, see below).
Meanwhile, packs that have lost breeders or helpers might be unable to maintain their former denning territories leading to re-establishment of ranges through territorial strife.
For example, if the surviving packs have multiple litters, they might seek to acquire larger ranges to sustain their offspring and they might be in need of a greater number of dens.
This could be achieved at the expense of packs that have been affected by loss of members and that cannot efficiently defend their resources.
Or else, such surviving packs with multiple breeders might eventually split into two breeding groups, once more, redefining the denning and foraging range boundaries.
Coincidentally, smaller packs (reduced due to hunting) might have to defend their kills from scavengers at a rate which is higher than observed in ‘regular-sized’ packs (relative to the specific ecosystem).
All of these processes are consistent with the necessity to defend or to acquire resources (including denning territories) that would affect testosterone levels in male wolves.
Increased cortisol, meanwhile, modifies bodily functions.
Cortisol ‘prepares’ the body to cope with the expected stress by increasing muscle tone and mobilizing energy stores.
However, such alterations are not characteristic to average living conditions in stable wolf populations and they come at expense of other investments on a physiological or psychological level.
Under stress or stress expectation circumstance, wolves function in ‘overdrive’ and if this state is sustained through repeated high rates of hunting by humans, the population inevitably deteriorates.
Other potential reasons behind the differential hormone production in the two studied wolf populations (tundra-taiga and boreal forest) have been discussed.
For example, tundra-taiga wolves have social systems that are formed around the caribou migration patterns.
They maintain territories only during the summer breeding season when the families are restricted to the denning area.
Once the pups are able to follow the pack, the tundra-taiga wolves track the migratory caribou and interactions with other partly nomadic wolves are more frequent in such populations (which could explain, e.g., the increased testosterone concentrations).
Boreal forest wolves maintain year-round territories within relatively stable residential populations.
Under such circumstance, intrapack encounters are more predictable and avoidable and territories do not become redefined as often.
Tundra-taiga wolves also suffer food shortages during summer.
If the caribou have migrated outside of the range near the den site, wolves have to rely on alternative resources and the social stress suffered during such periods of food-insecurity could result in higher cortisol levels.
Additionally, cortisol can mobilize energy stores to invest the energy in foraging efforts during times of scarcity and during times when the prey is ‘novel’ (different cognitive mechanisms must be applied in order to provide for the pack).
Tundra-taiga wolves might have a different hormonal baseline as determined by adaptions to the harsh life in the arctic.
Cortisol (stress hormone) concentrations might also be influenced not merely by the loss of pack mates itself and the resulting social instability but also by the perception of persecution.
Such concentrations would be higher in populations that are hunted with extremely invasive methods (e.g., aerial gunning), for prolonged periods and less predictably (shooting vs. trapping along traditional traplines that resident wolves come to recognize and avoid during hunting season).
The tundra-taiga wolves had been exposed to more invasive hunting than the boreal forest wolves.
However, in both populations, hunting mainly occurred during winter and therefore, the hormonal concentrations experienced during the hunting season were not directly reflected in the hair samples because hair does not grow in winter and thereby does not incorporate hormonal products.
Still, the consequences of the stress levels experienced during the hunting season might lead to differential hormonal production after the hunting season (indirect effects).
Despite the alternative explanations (e.g., habitat specifics, genetic baseline), the authors strongly argued that the adverse impact of hunting on wolf populations was a dominant factor of influence.
For example, the boreal forest control group exhibited higher cortisol levels than the boreal forest target group.
The control group shared the same habitat and the same genetic adaptations with the target group but the control group suffered higher hunting intensity.
Therefore, the increased cortisol levels in this group relative to the target group was likely the result of hunting pressure.
A reappraisal of the evidence for regulation of wolf populations (Cariappa, C.A. et al., 2011)
It has been long debated to what extent wolf population densities are regulated by available prey (ungulate) biomass or by intrinsic (biological, social) mechanisms.
This study aims to review previous data gathered in many established (namely, saturated rather than expanding, recently colonizing) wolf populations.
Data analysis demonstrates that the wolf populations are self-regulated rather than limited by prey biomass availability by at least a 3 : 1 margin.
Namely, wolf populations will follow prey biomass availability until a certain threshold has been reached where the intrinsic regulatory mechanisms will limit further wolf population density increase and the population will remain stable despite high numbers of prey available.
Initially, recently established wolf populations will grow but then they will stabilize around certain wolf numbers per area regardless of the biomass availability.
Some scientists have suggested such stable wolf populations reaching densities of 40 – 69 wolves / 1000 km2 (400 sq. miles).
However, wolf population densities are dependent on many factors and some wolf populations might reach higher densities than other even when population stability stage has been attained (e.g., Isle Royale wolf population).
These high densities are, fundamentally, an exception.
The numbers (40 – 60 wolves / 1000 km2 (400 sq. miles)), however, mostly reflect natural conditions (e.g., nature preserves) and wolf territories in more heavily human-impacted areas as well as less productive regions are usually larger (due to the lower concentration of prey and habitat fragmentation).
Consequently, wolf densities might be even lower.
For example, in a boreal forest system, Ontario, Canada wolf densities reached only 3 – 5 wolves / 1000 km2 (Kittle, A.M. et al., 2015).
These findings are extremely important because they suggest that in places of extreme ungulate abundance (e.g., many human-modified habitats) wolf populations will not reach unsustainable numbers and will become stabilized through biological and social mechanisms.
Lethal management is not necessary to keep the wolf populations at stable levels.
Predatory and reproductive senescence in wolves (MacNulty, D.R. et al., 2009 and Stahler, D.R. et al., 2012)
Wolf demographic dynamics are characterized by senescence processes that apply to the reproductive as well as hunting success.
Reproductive senescence begins at about the age of 4 – 5 while predatory senescence can already manifest itself at the age of 3 (hunting prowess increasing as the pup becomes an adult and then peaking at the age of 2).
Wolf populations subject to predator control are usually demographically younger than wolf populations that are not hunted or culled by humans.
The older individuals become removed and the pack structure is disrupted leading to territorial vacancies and prey resource availability that promotes the formation of new packs and production of many pups in order to repopulate the ranges.
New packs usually consist of the wolf pair (parents) and 1 generation of their offspring.
Established packs normally have the breeding adults as well as their spring pups and 1 – 2 generations of subordinate adults and subadults (older offspring).
Thus, in disturbed wolf groups, the social structure is skewed toward pups, (more rarely) yearlings and relatively few and relatively young adult wolves.
Accordingly, such populations have a larger proportion of individuals either at their peak food demand (pups) or approaching / at their peak reproductive and hunting performance.
The objective of reducing the wolf population or wolf population impact on prey species is not thereby achieved because the resident wolf community consists of high demand (developing) individuals and prime hunters / prime reproducers.
Retaining older individuals in the population would result in a greater variety of reproductive and hunting ability thus ensuring a natural mechanism of reducing wolf numbers per area as well as reducing the kill rates by wolves per capita.
Older individuals offer other benefits such as greater knowledge of territory and their resources (a perfected balance below carrying capacity and an advanced prey selectivity, e.g., pathogen control).
Older individuals have experience in keeping the pack cohesive at its top cooperation level and such packs can perform their ecosystem functions and services most efficiently.
Diversity in demographic age structure brings benefits to the wolf fitness well as to the ecosystem while reducing birth and kill rates.
COEXISTENCE
Occurrence and livestock depredation patterns by wolves in highly cultivated landscapes (Mayer, M. et al., 2022)
The study has been conducted in Jutland (Denmark and Germany) and it discusses as well as challenges the commonly applied concept of the ‘problem wolf’ through the analysis of livestock depredation rates in an intensely exploited agricultural area.
The findings suggest that the term ‘problem wolf’ should be replaced with ‘problem environment’.
Namely, the tendency to attack livestock is not dependent on the character of specific individuals but rather on the landscape (lack of natural habitat, lack of habitat connectivity, lack of wild prey, dense human settlements, dense agricultural areas compared to wild areas, unguarded livestock (lack of preventive measures), dense livestock populations compared to wild prey populations etc.).
Thus, the concept of ‘problem wolf’ should be shifted toward ‘problem landscape’ and rather than applying lethal measures to remove wolves, the problems within the landscape should be addressed and resolved in order to prevent predator attacks on livestock in the future.
If the problems in the landscape are not addressed and resolved, the next wolf that settles in this landscape, will also be likely to attack livestock.
The conflict rates are not dependent on which individual wolf is living in the area (or dispersing through the area).
The conflict rates are dependent on the circumstance in which the wolf finds itself.
A ‘problem wolf’ is not created through individual differences in character (e.g., boldness).
The ‘problem wolf’ is simply any wolf that is forced to navigate a ‘problem landscape’.
Therefore, if the individual involved in the conflict(s) is removed, the next individual that arrives in the area will be likely to become a new ‘problem wolf’.
The true causes of the conflict potential will not have been solved and the conflict rate will not be reduced for more than the period of time necessary for the new individual to replace the former wolf.
Moreover, the ‘target precision’ of removing the ‘problem wolves’ is very low and even if there were individuals more prone to conflict (which has not been scientifically proven), it is very unlikely that the specific individuals will be removed (usually, random individuals are removed in order to maintain a lower local population number).
As demonstrated in other publications, e.g., Santiago-Avila, F.J. et al., 2018 and Wieglus, R.B. & Peebles, K.A.,, persecution and removal of individuals (especially, residents) might result in an increased conflict rate.
The killing of the wolves without resolving the fundamental (landscape) issue will lead to no effects or adverse effects in the long term.
The study also shows that depredation risk is reduced substantially by introducing preventive measures (guardian dogs, fences).
Conflict rates on the Denmark’s side of Jutland study area were substantially (six times) lower than the conflict rates on the Germany’s side of the study area.
While some of the reasons are attributed to, e.g., landscape differences, sheep density etc., Denmark implements preventive livestock protection measures while preventive measures had not been implemented as extensively at the time in the Schleswig-Holstein province of Germany.
Additionally, it has been discovered that resident wolves are less likely to cause trouble with the livestock than migrating wolves.
Resident wolves are familiar with their territory, resources and prey movements as well as the risk factors (including mortality due to persecution, retaliation or human infrastructure).
Resident wolves have formed packs that are large and stable enough to secure wild prey.
Dispersing (migrating) wolves sometimes have to cross landscape that is not entirely wild (especially, in Europe where wild habitat is highly fragmented and the wolf cannot travel from one forest to another without crossing human-managed habitats, including pastures).
Dispersing wolves are not familiar with the territory they are travelling through and they do not know where prey may be located, therefore, as stated before, they will be more likely to rely on any prey that they come across (a greater level of opportunism).
Dispersing wolves travel alone and it is more difficult for them to kill large wild prey which is otherwise hunted in packs.
Livestock (and garbage, including such attractants as carcasses) can offer a lower-resistance resource if the wolf is prepared to tolerate the risk of encountering humans (or dogs).
In dispersing wolves, such risk tolerance might be higher due to the lack of reliable alternatives.
Coincidentally, resident wolves are often tracked and their locations are known to the scientists (especially, during the denning season) – their movements and settlement patterns are more predictable.
Dispersing wolves do not adhere to established routes and their locations are less predictable.
Therefore, it is easier to establish preventive measures in the areas where wolves have already settled.
Moreover, farmers who operate nearby resident wolf populations would have higher motivation to implement preventive measures (compared to farmers who live outside wolf-recolonized areas but whose land might be occasionally travelled by dispersing wolves.
Governmental and other types of funding available to farmers who introduce preventive measures is also extended to operations in high risk areas while those may not be the only farms on ‘problem landscape’ with a wolf migration potential.
In order to reduce conflict risk due to dispersing wolves, it is important to keep the wild habitats connected so that dispersing wolves (who demonstrate high aversion to human settlements and prefer staying away from anthropogenic landscape) did not have to cross pastures or even to approach pastures during migration.
A new era of wolf management (Kareiva, P. et al., 2022)
While this publication is specific to data gathered in the USA, the conclusions are relevant to any wolf management region.
Firstly, the study underlines that the livestock losses attributed to wolves are frequently overestimated misleading the public perception of the threat posed by wolves and thereby encouraging vilification and persecution of wolves.
For example, the United States Department of Agriculture (USDA) presents 5-year reports on livestock losses attributed to both non-predator and predator causes.
Both categories constitute the ‘unwanted losses’ estimate that reached 10% for sheep in 2020 and 3% for cattle in 2005 (latest reports respective to the study publishing date).
Wolf-depredation never accounted for more than 0.21% for sheep and 0.05% for cattle (out of total inventory) while most livestock deaths were caused by non-predator factors (inclement weather, birthing problems, plant poisoning etc.).
Moreover, these wolf-depredation estimates are likely overrepresented because the USDA combines both confirmed and probable cases in one figure assuming that every probably case was, verily, caused by wolves.
There is a greater than tenfold difference between the confirmed and probable case rates (e.g., out of the 2834 reported cattle losses in 2015 in Idaho, Montana and Wyoming reported by the USDA as putative predation incidents, only 148 were confirmed wolf kills).
Even the confirmed wolf kills do not always constitute reliable estimates because confirmation quality can be variable.
For example, cattle exhibiting no clear depredation patterns have been assigned to the ‘wolf predation’ incidents under the justification that ‘the cattle tried to escape from the wolves and died due to overexertion’.
Similarly, it can be notably difficult to differentiate between depredation and scavenging (feeding by wolves or by other canids, e.g., coyotes or stray dogs, on carcasses of animals that died due to other causes).
In many countries, expert examinations and DNA testing of saliva extracted from the wounds are applied and scientists are consulted to confirm wolf presence in the area.
While it might sound ‘needlessly basic’, The Humane Society of the United States’ publication attests to attribution of livestock losses to predators by the USDA on such ludicrous occasions when, e.g., livestock growers have claimed their livestock lost to grizzly bears in states where grizzly bears are absent or have never occurred, historically.
Misleading statistics represented in the USDA reports lead to increased hostility toward predators on behalf of the livestock producers or the general public.
Biased reports also contribute to inflated risk perception that perpetuates certain historical myths of the imagined threats posed by wolves and other large predators and that are not grounded in facts and actual risk rates.
Secondly, a devastating aspect is discussed in the publication, namely, that of the collateral damage resulting from wolf trapping.
Traps and snares set with the purpose of hunting or culling wolves cannot be controlled by the trapper, and other species may suffer severe injury or death.
For example, legally reported data on ‘incidental captures’ (non-target species caught in traps or snares) attest to high rates of casualties among mountain lions (40 – 50%), domestic dogs (25 – 47%) and ungulates (10%).
Many endangered species suffer harmed, as well, e.g., lynx (3%), golden eagle (3%), wolverine (< 1%).
While these percentages are lower in the endangered species, it is important to bear in mind that the endangered species populations are sparser (more abundant species of lesser conservational concern have higher probability rates of becoming captured) but, in these species, every individual might be highly important with respect to the conservation prospects (especially, breeding individuals).
The figures provided in the publication refer to the reported casualties and it is not known how many incidents have not been reported.
Thirdly, the publication refers to the true cost accountancy which should be invoked when strategizing large predator management.
As mentioned before, wolf-caused livestock damage rates are extremely low (even when overrepresented).
Yet these are the only ‘numbers’ that are included in ‘balance estimates’.
Meanwhile, wolf management plans never consider the benefits by wolves to the ecosystems and society (environmental services and economic gains).
For example, while wolves cause minimal damage to livestock that can be further reduced by applying preventive measures, wolves also lead to decreased deer-vehicle collision rates (by as much as 20% according to Raynor, J.L. et al., 2021), they bring tourism-related income of $82 billion annually (in Idaho, Montana, Wyoming according to RRC Associates, 2020), they provide essential ecosystem services such as increased productivity, pathogen control (including pathogens that affect livestock), cleaner water, increased biodiversity etc.
Some of these benefits are difficult or impossible to quantify (e.g., how many livestock survived due to reduced disease transmission from wild populations or to what extent the water quality was improved and how it translated into financial gains due to, for example, reduced health care costs).
However, these are real benefits and they significantly exceed the costs posed by large predators.
In management planning, cultural values are disregarded, as well.
In the US, the wolf is the icon of wild America and a symbol of freedom as well as loyalty and strong family bonds.
Many Native American groups consider wolves a part of their spiritual legacy.
Finally, wolf management decisions are frequently drawn without sufficient public consultation or even contrary to public stand (disregarding fundamental democracy principles).
All of these considerations should be considered when drafting wolf management plans.
Are wolves dangerous to humans? (Linnell, J.D.C. et al., 2021)
Sometimes in areas where wolves have been extirpated and where they have not loved for a long time but where they have returned to reclaim their former range, people have lost knowledge of coexistence and of wolf ecology therefore they are afraid of wolves and they wonder if wolves might attack humans.
This study shows that, for example, during the period from 2002 and 2020 (18 years), there have only been 2 fatal attacks by wolves on humans in the whole North America (+4 non-fatal attacks).
The 1 fatal attack (in 18 years) on an adult human female in the US occurred in southwestern Alaska, in 2010, and the reason for the attack cannot be extrapolated with utmost certainty therefore, it has been listed as a predatory attack (compared to defense, perceived food competition, rabid attacks etc.), i.e. the human was possibly attacked as prey.
The other fatal attack occurred in northern Saskatchewan, Canada (2005) was also considered predatory and it involved an adult human male.
There have been no fatal attacks during this 18-year-period in Europe. There have been 11 non-fatal attacks in Europe that, in 9 cases, resulted in bites (you can read the details on pp. 16 – 17).
Worldwide, during 18 years, there have been 26 (registered) fatal attacks on humans (most – in Asia); 14 of these attacks – due to rabies; 3 – defensive (provoked attacks); 9 – predatory attacks.
Worldwide, during 18 years, there have been 463 (registered) non-fatal attacks on humans (most – in Asia); 366 of these attacks – due to rabies; 39 – defensive (provoked attacks); 39 – predatory attacks.
Food-related/defensive attacks are mostly provoked by the human who, unknowingly, threatens the wolf’s food resource or pups, or other aspects of immediate safety and who fails to recognize the warning issued by the wolf before the wolf is forced to attack to remove the threat.
Some causes of attacks cannot be disentangled with confidence because the survivor might not have perceived a threat to wolf’s safety or food proximity.
The wolf attack risk on humans is above zero but it is also too low to be even calculated.
On pp. 35 (Table 3) useful guidelines can be found to advise on risk assessment and recommended behaviour upon several observed behaviours of wolves during encounters.
Killing wolves to prevent predation on livestock may protect one farm but harm neighbours (Santiago-Avila, F.J. et al., 2018)
This research shows that trapping or shooting wolves in order to protect livestock on one farm will not result in a long-term decrease in conflict rates in the area but will rather displace the conflicts affecting the neighbouring farms instead.
This occurs through a simple displacement of the problem.
When persecution (threat) increases in one area, wolves move to another area and while the respective farmer might experience (temporary) ‘relief’ and therefore attest to the efficiency of the lethal measures, the actual conflict rates do not drop at all – the conflict merely has been ‘moved to the neighbours’.
Namely, during the same year there is an increased risk for farms up to 5.42 km distant from the original conflict site (where traps have been set thus exposing wolves to prolonged threat which encourages movement away from the original conflict site) to experience a new conflict.
Also, if neighbouring farms experience increased conflict rates due to displaced wolves from the original ‘problem site’, this might be perceived as increased conflict rates per se and the public (farmers) might call for extensive cull.
That is to say, farmers believe that there are several wolf packs causing the problem while there is, in truth, one pack which simply moved away from the original site due to persecution.
This could lead to overestimates of the local wolf population and of the rate of the problem (it can be assumed that there are, for example, 8 wolves involved while there are only 4 wolves counted twice).
A Ranchers Guide to Coexistence Among Livestock, People, and Wolves, 2nd Edition (Parr, S. et al., 2017, Wolf Awareness)
I highly recommend this guide for livestock farmers which has been developed in Canada but most if not all of the measures can be applied in other world regions (directly or through slight adaptations).
In the guide the best methods of preventive, non-lethal action (that are the only sustainable and cost-effective long-term solutions to wolf-livestock conflict) have been summarized.
The following approaches are included and discussed (providing practical recommendations):
- Husbandry practices (how to stay ‘unattractive’ to predators by, e.g., ensuring carcass removal from the sites);
- Working with nature (e.g., adjusting livestock births to fawning pulses in wild ungulate populations in order to deter the predators from lambs and calves etc. to wild ungulate fawns);
- Surveillance and monitoring (employing shepherds, herders, range riders etc.);
- Barriers (fences, electric fences, fladry);
- Livestock guardian animals (dogs, donkeys, llamas, long-horned steers etc.);
- Seasonal attractants (vulnerable times in livestock operations such as branding, birthing, herds with juveniles etc.);
- Property risk assessment (not all properties are in dire need of anti-predator protection and the guide offers risk assessment considerations);
- Strategic grazing (improving livestock movement through, e.g., low stress handling as well as enhancing herd cohesion and natural protectiveness toward vulnerable individuals etc.);
- Planning of livestock operation features (e.g., designing the watering system in order to draw the livestock away from forest etc.);
- Technologies (sound, light effects, guard boxes activated by radio-collared wolves etc.);
- Compensation programmes for livestock losses (requirements for compensation and rates).
Chapter on the inefficiency of lethal wolf management introduces scientific insight into the actual success rates (or rather the lack thereof) of wolf removal on further conflict risk.
It is recommended to consult with biologists and to estimate where resident wolf populations are located, where they den and where their movements are predicted to occur annually or during vulnerable periods (such as lambing, calving).
Thereby, risk assessment can be conducted and actions can be taken where necessary.
Wolf conservation organizations also suggest that in high risk areas compensation for livestock should only be handed out to farmers who have already implemented preventive measures and government-funded fencing/guarding dog programmes should be initiated to assist the farmers with the potentially costly investments.
Also, compensations should be paid out upon confirmation of the cause of death and misattribution of livestock death to wolves where other mortality factors have been at play (and wolves have not been involved at all or they have scavenged on the unremoved carcass), should be avoided.
Depredation confirmations are usually provided by government agency experts through inspection of the carcass and mortality site or through DNA analysis of saliva extracted from the carcass.
In some cases, biologists are consulted to determine the (probability of the) presence of wolves (and other large predators) in the area.
Food habits of the world’s grey wolves (Newsome, T.M. et al., 2016)
The study discusses wolf diet in different parts of the world and, accordingly, the results can inform us on the livestock depredation risk in different world regions.
The livestock depredation risk is the highest in Asia (where, for example, nomadic farmers move their livestock freely through the wild and semi-wild areas (livestock is less isolated from the wild landscape), where livestock carcasses are more often made available for scavenging and where wolves are highly adapted to living on grasslands where habitat is shared with grazing livestock.
Consequently, livestock depredation risk in the Asian countries: ~ 50%.
The risk (as assessed by the percentage of consumed biomass of livestock in wolves’ diet) is also higher in Europe: ~ 30% (than in North America).
This is due to the lack of wild areas (most of the European landscape is of anthropogenic character), fragmented habitats, dense human settlements, intensely farmed agricultural areas and other factors (e.g., lack of wild prey, frequent encounters with livestock, improper livestock carcass management, access to human garbage).
Still, it has been estimated that, on average, in Europe large predators (wolves, bears, lynx) only cause 0.05 – 0.06% sheep deaths out of the entire European stock (the sheep being the most frequent victim to predation).
These percentages, however, vary from country to country and from region to region in accordance with the aforementioned factors as well as preventive coexistence measures applied.
Also, studies in southern Italy demonstrate a decrease in livestock depredation rates by wolves in areas where wild ungulate populations have recovered and increased in abundance, i.e., where wild prey is adequately available, wolves select wild prey over livestock and the conflict rates experience a reduction.
In North America where large, contiguous and relatively remote wilderness areas as well as abundant wild prey populations are more readily available, the wolf diet includes the least amount of the domestic species (only ~ 8%).
The percentages of livestock consumed have been calculated with respect to wild prey consumed.
The percentage values indicated for the three world regions are average values and cannot be reflective of differences on smaller scale (e.g., there are regions in Europe where livestock consumption rate fall below 2% as well as regions where the rates rise above the Europe’s average of 30%.
The aforementioned changes in wolf diet (and depredation) patterns in Italy have been discussed, e.g., in the publication by Merrigi, A. et al., 2011.
With increasing wild ungulate densities in different regions in Italy over time, wild ungulate percentage in wolf diet rose from 0% (province of Genoa; 1987), 0% (Umbria region; 1985) and 16% (Pollino National Park; 1999) to 70% (2004), 26% (1996) and 60.4% (2004), respectively.
The percentage of wolf diet not representative of wild ungulate consumption refers to alternative food resources (including livestock and garbage).
It was observed that wolf diet was more varied (including a greater number of alternative prey sources) until wild ungulate densities reached values above 40 – 50% after which the diet breath (diversity of prey) dropped and was dominated by wild ungulates.
Effects of wolf mortality on livestock depredations (Wieglus, R.B. & Peebles, K.A., 2014)
This research study demonstrates that wolf culling increases wolf-livestock conflict rates when the rates are analyzed in a 2 year period.
The depredation risk rates may increase by 4% for sheep and 5-6% for cattle in the year following the cull (moreover, the risk further increases with each additional wolf culled).
This is caused by several consequences to the cull.
For example, wolf social group disruption (especially, loss of breeding male and female) might lead to pack break-up or temporal instability which results in increased migration by wolves (dispersal) during which wolves are more likely to cross agricultural territories.
Dispersing and roaming wolves are more likely to attack livestock than resident wolves because dispersing wolves often travel in an unfamiliar landscape where they cannot efficiently locate wild prey.
It is also difficult for solitary wolves to kill large wild ungulates which are normally hunted in packs.
Lone wolves are likelier to depend on opportunistically encountered prey such as livestock.
Social group disruption can leave wolves without stable, large packs that would normally have experienced, elder members that profess knowledge of hunting strategies as well as familiarity with the local landscape and an acquired proficiency at maintaining efficient group cooperation levels.
Loss of experienced adults decreases wolf hunting success even if the pack stays together.
Small and inexperienced wolf packs might not be able to hunt down elk, deer, moose and other wild prey and thereby, they might be forced to rely on food resources that they encounter opportunistically and that are easier to subdue.
Additionally, culled wolf populations tend to reproduce at greater rates while the smaller pack size can result in smaller wolf territories.
Thus, following a cull, the local population might actually become denser instead of sparser with unstable, small, inefficient packs that cannot sustain themselves on wild prey.
Notes by Ieva 