Wolf Survival Research Articles

Harvest of transboundary grey wolves from Yellowstone National Park is largely additive

Abstract Large carnivores are globally threatened due to habitat fragmentation and loss, prey depletion and human exploitation. Human exploitation includes both legal and illegal hunting and trapping. Protected areas can create refugia from hunting and trapping; however, hunting can still threaten wide‐ranging large carnivores when they leave these areas. Large carnivore reintroductions to protected areas are often motivated to restore ecological processes, including wolf reintroduction to Yellowstone National Park (YNP). Determining if harvest is compensatory or additive is essential for informed conservation strategies, as it influences the overall impact on wolf populations and their ecosystems. If harvest was compensatory, then increasing harvest pressure outside YNP should not decrease overall survival for transboundary wolves. Alternatively, if increasing harvest was additive, then increasing harvest pressure outside YNP should decrease overall survival for transboundary wolves. We tested the effects of variable harvest pressure following delisting on the survival of YNP grey wolves (Canis lupus) from 1995 to 2022. We defined three harvest levels: no harvest, harvest with limited quotas and unlimited harvest. We used Cox‐proportional hazards models and cumulative incidence functions to estimate survival rates, factors affecting survival and cause‐specific mortality between these three harvest periods to test predictions of the additive mortality hypothesis. Most harvested wolves that primarily lived in YNP were killed adjacent to the park border. Cox‐proportional hazards models revealed that mortality was highest during years of unlimited harvest during winter outside YNP. Cause‐specific mortality analyses showed that natural mortality from other wolves and harvest were the two leading causes of death, but that harvest mortality had additive effects on wolf mortality. Wolf survival decreased with increased harvest mortality, while natural mortality remained relatively unchanged. Synthesis and applications. High rates of additive harvest mortality of wolves could negatively impact wolf survival in YNP. Harvest mortality of transboundary wolves is additive possibly due to source‐sink dynamics of uneven spatial susceptibility of wolves to harvest mortality across protected area borders, as well as effects of harvest on complex social dynamics of wolves in YNP. Transboundary management of large carnivores is challenging, yet cooperation between agencies is vital for wolf management in and around YNP. Our results support the use of small quota zones surrounding protected areas, that minimize transboundary mortality impacts on large carnivores living primarily inside protected areas.

Recent Trends in Survival and Mortality of Wolves in Minnesota, United States

Survival is a key determinant of population growth and persistence; computation and understanding of this metric is key to successful population management, especially for recovering populations of large carnivores such as wolves. Using a Bayesian frailty analytical approach, we evaluated information from 150 radio-tagged wolves over a 16-year time period to determine temporal trends and age- and sex-specific survival rates of wolves in Minnesota, United States. Based on our analyses, overall annual survival of wolves during the study was 0.67, with no clear evidence for age- or sex-specific differences in the population. Our model demonstrated statistical support for a temporal trend in annual survival; the highest survival was predicted at the beginning of the time series (0.87), with lowest survival (0.55) during 2018. We did not observe evidence that survival was markedly reduced during years when a regulated hunting and trapping season was implemented for wolves (years 2012–2014). However, cause-specific mortality analysis indicated that most mortality was human-caused. While the estimate for increasing human-caused mortality over time was positive, the evidence was not statistically significant. Anthropogenic causes resulted in ∼66% of known mortalities, including legal and illegal killing, and vehicular collisions. Trends in wolf survival in Minnesota may reflect an expanding distribution; wolf range has spread to areas with more human development during the study, presumably leading to increased hazard and reduced survival. Our results provide foundational information for evaluating and guiding future policy decisions pertaining to the Great Lakes wolf population.

FOOT INJURIES IN MICHIGAN, USA, GRAY WOLVES (CANIS LUPUS), 1992-2014.

The range of gray wolves (Canis lupus) in the contiguous US is expanding. Research and monitoring to support population recovery and management often involves capture via foothold traps. A population-level epidemiologic assessment of the effect of trap injuries on wolf survival remains needed to inform management. We describe the baseline rate, type, and severity of foot injuries of wolves born 1992-2013 in Michigan's Upper Peninsula, evaluate the reliability of field-scoring trap-related injuries, and the effect of injuries on wolf survival. We assessed foot injuries by physical and radiographic exam at postmortem and/or time of capture for 351 wolves using the International Organization for Standardization 10990-5 standard and the effects of injuries, sex, age, previous capture and body condition on survival using proportional hazards regression. We used ordinal regression to evaluate epidemiologic associations between sex, age, previous capture, body condition, cause of death and injury severity. Most wolves (53%) experienced no physically or radiographically discernable foot injuries over their lifetimes. Among those wolves that did experience injuries, 33% scored as mild. Foot injuries had little epidemiologically discernable effect on survival rates. Wolves with higher foot trauma scores did experience an increased risk of dying, but the magnitude of the increase was modest. Most limb injuries occurred below the carpus or tarsus, and scoring upper-limb injuries added little predictive information to population-level epidemiologic measures of survival and injury severity. There was little association between injury severity and cause of death. Based on necropsy exams, previous trap injuries likely contributed to death in only four wolves (1.1%). Our results suggest that injuries resulting from foothold traps are unlikely to be a limiting factor in recovery and ongoing survival of the Michigan gray wolf population.

Quantifying the effects of delisting wolves after the first state began lethal management.

Predators and their protection are controversial worldwide. Gray wolves, Canis lupus, lost U.S. federal protection (delisting) and the State of Wisconsin began lethal management first among all states and tribes that regained authority over wolves. Here we evaluated the initial success of reaching the state’s explicit objective, “…to allow for a sustainable harvest that neither increases nor decreases the state’s wolf population…” We used official state figures for hunter-killed wolves, population estimates from April 2017–2020, and the latest peer-reviewed model of individual wolf survival to estimate additional deaths resulting from federal delisting. More than half of the additional deaths were predicted to be cryptic poaching under the assumption that this period resembled past periods of liberalized wolf-killing in Wisconsin. We used a precautionary approach to construct three conservative scenarios to predict the current status of this wolf population and a minimum estimate of population decline since April 2020. From our scenarios that vary in growth rates and additional mortality estimates, we expect a maximum of 695–751 wolves to be alive in Wisconsin by 15 April 2021, a minimum 27–33% decline in the preceding 12 months. This contradicts the state expectation of no change in the population size. We draw a conclusion about the adequacy of regulatory mechanisms under state control of wolves and discuss the particular governance conditions met in Wisconsin. We recommend greater rigor and independent review of the science used by agencies to plan wolf hunting quotas and methods. We recommend clearer division of duties between state wildlife agencies, legislatures, and courts. We recommend federal governments reconsider the practice of sudden deregulation of wolf management and instead recommend they consider protecting predators as non-game or transition more slowly to subnational authority, to avoid the need for emergency relisting.

The importance of wilderness to wolf (Canis lupus) survival and cause-specific mortality over 50 years

We assessed the relative importance of wilderness to gray wolf (Canis lupus) population dynamics over 50 years in a population that 1) was long extant (i.e., not reintroduced or recolonized), 2) was not subject to harvest in our study area until recently, and 3) used both wilderness and adjacent, mainly public, non-wilderness. We analyzed the survival of radiocollared wolves (n = 756 collared-wolf tenures) during 1968–2018 in the Superior National Forest, Minnesota, USA, including the Boundary Waters Canoe Area Wilderness. Over 50 years, adult annual survival was 78%. Wolves captured in wilderness tended to exhibit higher survival than those captured in non-wilderness, but the difference was more pronounced during harvest years and post-harvest years when wilderness wolf survival remained relatively high and non-wilderness wolf survival dropped (relative to pre-harvest). During Nov–Apr of pre-harvest years for adults, the natural mortality rate was similar for non-wilderness wolves and wilderness wolves (both 6%), but the anthropogenic mortality rate was higher for non-wilderness wolves than wilderness wolves (7% versus 1%), as was the illegal mortality rate (5% versus 1%). During Nov–Apr of pre-harvest years, wilderness wolves were less likely to die than non-wilderness wolves (p = 0.042; hazard ratio = 0.59), pups were more likely to die than adults (p = 0.002; hazard ratio = 1.84), and males were less likely to die than females (p = 0.053; hazard ratio = 0.73). Our long-term wolf survival, cause-specific mortality, and hazard results will inform management agencies whenever wolves are delisted, and jurisdiction for them passes to states.

Compensatory mortality in a recovering top carnivore: wolves in Wisconsin, USA (1979–2013)

Populations of large terrestrial carnivores are in various stages of recovery worldwide and the question of whether there is compensation in mortality sources is relevant to conservation. Here, we show variation in Wisconsin wolf survival from 1979 to 2013 by jointly estimating the hazard of wolves' radio-telemetry ending (endpoint) and endpoint cause. In previous analyses, wolves lost to radio-telemetry follow-up (collar loss) were censored from analysis, thereby assuming collar loss was unconfounded with mortality. Our approach allowed us to explicitly estimate hazard due to collar loss and did not require censoring these records from analysis. We found mean annual survival was 76% and mean annual causes of mortality were illegal killing (9.4%), natural and unknown causes (9.5%), and other human-caused mortality such as hunting, vehicle collisions and lethal control (5.1%). Illegal killing and natural mortality were highest during winter, causing wolf survival to decrease relative to summer. Mortality was highest during early recovery and lowest during a period of sustained population growth. Wolves again experienced higher risk of human-caused mortality relative to natural mortality as wolves expanded into areas with more human activity. We detected partial compensation in human- and natural-caused mortality since 2004 as the population saturated more available habitat. Prior to 2004, we detected additivity in mortality sources. Assessments of wolf survival and cause of mortality rates and the finding of partial compensation in mortality sources will inform wolf conservation and management efforts by identifying sources and sinks, finding areas of conservation need, and assessing management zone delineation.

Desert pastoralists' negative and positive effects on rare wildlife in the Gobi.

In arid regions of the developing world, pastoralists and livestock commonly inhabit protected areas, resulting in human-wildlife conflict. Conflict is inextricably linked to the ecological processes shaping relationships between pastoralists and native herbivores and carnivores. To elucidate relationships underpinning human-wildlife conflict, we synthesized 15 years of ecological and ethnographic data from Ikh Nart Nature Reserve in Mongolia's Gobi steppe. The density of argali (Ovis ammon), the world's largest wild sheep, at Ikh Nart was among the highest in Mongolia, yet livestock were >90% of ungulate biomass and dogs >90% of large-carnivore biomass. For argali, pastoral activities decreased food availability, increased mortality from dog predation, and potentially increased disease risk. Isotope analyses indicated that livestock accounted for >50% of the diet of the majority of gray wolves (Canis lupus) and up to 90% of diet in 25% of sampled wolves (n = 8). Livestock composed at least 96% of ungulate prey in the single wolf pack for which we collected species-specific prey data. Interviews with pastoralists indicated that wolves annually killed 1-4% of Ikh Nart's livestock, and pastoralists killed wolves in retribution. Pastoralists reduced wolf survival by killing them, but their livestock were an abundant food source for wolves. Consequently, wolf density appeared to be largely decoupled from argali density, and pastoralists had indirect effects on argali that could be negative if pastoralists increased wolf density (apparent competition) or positive if pastoralists decreased wolf predation (apparent facilitation). Ikh Nart's argali population was stable despite these threats, but livestock are increasingly dominant numerically and functionally relative to argali. To support both native wildlife and pastoral livelihoods, we suggest training dogs to not kill argali, community insurance against livestock losses to wolves, reintroducing key native prey species to hotspots of human-wolf conflict, and developing incentives for pastoralists to reduce livestock density.

Perspectives on the Iberian wolf in Portugal: population trends and conservation threats

The Iberian wolf (Canis lupus signatus), an endemic subspecies of the Iberian Peninsula, is endangered in Portugal. Contrary to the rest of Europe, the distribution of this subspecies has been declining in Portugal throughout the twentieth century to the present day. Knowledge of the Iberian wolf in Portugal is limited and this lack of detailed scientific knowledge makes it difficult to evaluate conservation priorities. To fill this gap, we summarize existing knowledge regarding trends and potential threats and provide a perspective on Iberian wolf population trends in Portugal, identifying potential factors modulating such trends. Priorities for research and existing monitoring gaps are presented. Declines are primarily associated with a scarcity of wild prey with consequent livestock predation, and illegal persecution primarily in retaliation for predation on livestock. If these limiting causal factors continue operating, Iberian wolf survival in Portugal is jeopardized. Wolf conservation will benefit from a long-term project including public awareness, scientific research and conservation and management solutions to protect this endangered subspecies. Future research should focus on the mechanisms regulating population size, territory occupancy and interactions with prey species, both domestic and wild.

The Challenges of Red Wolf Conservation and the Fate of an Endangered Species Recovery Program

AbstractEndangered red wolves (Canis rufus) receive intense conservation efforts in the United States, and to date, population recovery has been challenged by hybridization with closely related coyotes (C. latrans) and illegal human‐caused mortality. Ongoing review of the red wolf program in the single recovery area in North Carolina prompted us to compare demography (survival, recruitment) and cause of death of red wolves and coyotes/hybrids. In most respects, canids had similar demographic rates, although sterilization was effective in controlling coyote reproduction. Comparison of previous (1999‐2007) to contemporary (2009‐2014) causes of death revealed that shooting mortality consistently accounted for ∼25% of wolf mortality. As evidenced by the lack of coyote deaths from strife with wolves, and stationary/declining wolf numbers during the last 15 years, current conditions are inadequate to establish a viable self‐sustaining wolf population. Accordingly, the program review should determine whether: (1) banning coyote hunting will sufficiently benefit wolf survival or recruitment; (2) the wolf population should be considered conservation‐reliant under revised recovery goals; or (3) the recovery program in North Carolina should be abandoned.

Density-dependent intraspecific aggression regulates survival in northern Yellowstone wolves (Canis lupus).

Understanding the population dynamics of top-predators is essential to assess their impact on ecosystems and to guide their management. Key to this understanding is identifying the mechanisms regulating vital rates. Determining the influence of density on survival is necessary to understand the extent to which human-caused mortality is compensatory or additive. In wolves (Canis lupus), empirical evidence for density-dependent survival is lacking. Dispersal is considered the principal way in which wolves adjust their numbers to prey supply or compensate for human exploitation. However, studies to date have primarily focused on exploited wolf populations, in which density-dependent mechanisms are likely weak due to artificially low wolf densities. Using 13 years of data on 280 collared wolves in Yellowstone National Park, we assessed the effect of wolf density, prey abundance and population structure, as well as winter severity, on age-specific survival in two areas (prey-rich vs. prey-poor) of the national park. We further analysed cause-specific mortality and explored the factors driving intraspecific aggression in the prey-rich northern area of the park. Overall, survival rates decreased during the study. In northern Yellowstone, density dependence regulated adult survival through an increase in intraspecific aggression, independent of prey availability. In the interior of the park, adult survival was less variable and density-independent, despite reduced prey availability. There was no effect of prey population structure in northern Yellowstone, or of winter severity in either area. Survival was similar among yearlings and adults, but lower for adults older than 6 years. Our results indicate that density-dependent intraspecific aggression is a major driver of adult wolf survival in northern Yellowstone, suggesting intrinsic density-dependent mechanisms have the potential to regulate wolf populations at high ungulate densities. When low prey availability or high removal rates maintain wolves at lower densities, limited inter-pack interactions may prevent density-dependent survival, consistent with our findings in the interior of the park.

A protected area influences genotype‐specific survival and the structure of a Canis hybrid zone

It is widely recognized that protected areas can strongly influence ecological systems and that hybridization is an important conservation issue. However, previous studies have not explicitly considered the influence of protected areas on hybridization dynamics. Eastern wolves are a species of special concern and their distribution is largely restricted to a protected population in Algonquin Provincial Park (APP), Ontario, Canada, where they are the numerically dominant canid. We studied intrinsic and extrinsic factors influencing survival and cause-specific mortality of hybrid and parental canids in the three-species hybrid zone between eastern wolves, eastern coyotes, and gray wolves in and adjacent to APP. Mortality risk for eastern wolves in areas adjacent to APP was significantly higher than for other sympatric Canis types outside of APP, and for eastern wolves and other canids within APP. Outside of APP, the annual mortality rate of all canids by harvest (24%) was higher than for other causes of death (4-7%). Furthermore, eastern wolves (hazard ratio = 3.5) and nonresidents (transients and dispersing animals, hazard ratio = 2.7) were more likely to die from harvest relative to other Canis types and residents, respectively. Thus, eastern wolves dispersing from APP were especially vulnerable to harvest mortality. For residents, eastern wolf survival was more negatively influenced by increased road density than for other Canis types, further highlighting the sensitivity of eastern wolves to human disturbance. A cycle of dispersal from APP followed by high rates of mortality and hybridization appears to maintain eastern wolves at low density adjacent to APP, limiting the potential for expansion beyond the protected area. However, high survival and numerical dominance of eastern wolves within APP suggest that protected areas can allow rare hybridizing species to persist even if their demographic performance is compromised and barriers to hybridization are largely absent in the adjacent matrix.

Evaluating the efficacy of non-invasive genetic methods and estimating wolf survival during a ten-year period

Genetic capture-recapture (CR) analysis is a highly promising tool to estimate population parameters and monitor populations through time. However, its level of accuracy has rarely been assessed and comparisons with traditional estimates in controlled settings have rarely been performed. We used CR analysis with long-term fecal genotyping data and applied open-population models to estimate survival rates and assess trend in abundance of wolves in Isle Royale over 10 years, while simultaneously estimating those parameters with traditional aerial-based techniques that are believed to be reasonably accurate. Comparison of the techniques indicated that there is a good correspondence of estimates only when the effort in genetic sampling is high, which guarantees a high recapture probability. Juvenile wolves had higher annual CR survival rates than adult wolves; kill rates most affected wolf sur- vival in this natural ecosystem, and higher annual kill rates were correlated with higher annual adult survival. Adult survival (but not juvenile survival) was an important pre- dictor of population growth rate. Hence, we show that kill rates indirectly affected population growth rate and directly affected adult survival rate. These reliable estimates of survival have unique value because the Isle Royale wolf population is not exposed to any human-caused mortality. Therefore, knowing long-term patterns of annual survival and its relationship to population growth rate for a not hunted wolf population represents a critical baseline for wolf conservation throughout its worldwide distribution.

Maned wolf survival rate in central Brazil

AbstractAlthough many carnivores are of conservation concern, most are poorly studied. The maned wolf Chrysocyon brachyurus Illiger, 1811 is the largest South American canid with a broad distribution; however, the largest portion of its range is in the Brazilian Cerrado savannah, where due to intensive agricultural expansion, it is threatened by habitat loss. Maned wolf population trends are virtually unknown. We analyzed radio telemetry data from a 13‐year study in Emas National Park, central Brazil, with Burnham's live recapture/dead recovery models in the program MARK to obtain the first analytically sound estimate of the apparent maned wolf survival rate. We constructed 16 candidate models including variation in survival rate and resighting probability associated with an individual's sex or age and year of study. Apparent adult survival rate throughout the study ranged from 0.28 (se=0.08) to 0.97 (se=0.06). There was no evidence for sex specificity but strong support for time variation. Model weights supported an age effect and the subadult survival rate was 0.63 (se=0.15). Results indicate similar life patterns for male and female maned wolves and similar mortality risks for adults and subadults in the study area. The observed temporal fluctuations of adult survival rate are important for population dynamics as they decrease average population growth rates. Population dynamics are central for conservation planning and our results are an important step towards a better understanding of the maned wolf's ecology.

Survival of Colonizing Wolves in the Northern Rocky Mountains of the United States, 1982–2004

Abstract: After roughly a 60‐year absence, wolves (Canis lupus) immigrated (1979) and were reintroduced (1995‐1996) into the northern Rocky Mountains (NRM), USA, where wolves are protected under the Endangered Species Act. The wolf recovery goal is to restore an equitably distributed metapopulation of ≥30 breeding pairs and 300 wolves in Montana, Idaho, and Wyoming, while minimizing damage to livestock; ultimately, the objective is to establish state‐managed conservation programs for wolf populations in NRM. Previously, wolves were eradicated from the NRM because of excessive human killing. We used Andersen–Gill hazard models to assess biological, habitat, and anthropogenic factors contributing to current wolf mortality risk and whether federal protection was adequate to provide acceptably low hazards. We radiocollared 711 wolves in Idaho, Montana, and Wyoming (e.g., NRM region of the United States) from 1982 to 2004 and recorded 363 mortalities. Overall, annual survival rate of wolves in the recovery areas was 0.750 (95% CI = 0.728‐0.772), which is generally considered adequate for wolf population sustainability and thereby allowed the NRM wolf population to increase. Contrary to our prediction, wolf mortality risk was higher in the northwest Montana (NWMT) recovery area, likely due to less abundant public land being secure wolf habitat compared to other recovery areas. In contrast, lower hazards in the Greater Yellowstone Area (GYA) and central Idaho (CID) likely were due to larger core areas that offered stronger wolf protection. We also found that wolves collared for damage management purposes (targeted sample) had substantially lower survival than those collared for monitoring purposes (representative sample) because most mortality was due to human factors (e.g., illegal take, control). This difference in survival underscores the importance of human‐caused mortality in this recovering NRM population. Other factors contributing to increased mortality risk were pup and yearling age class, or dispersing status, which was related to younger age cohorts. When we included habitat variables in our analysis, we found that wolves having abundant agricultural and private land as well as livestock in their territory had higher mortality risk. Wolf survival was higher in areas with increased wolf density, implying that secure core habitat, particularly in GYA and CID, is important for wolf protection. We failed to detect changes in wolf hazards according to either gender or season. Maintaining wolves in NWMT will require greater attention to human harvest, conflict resolution, and illegal mortality than in either CID or GYA; however, if human access increases in the future in either of the latter 2 areas hazards to wolves also may increase. Indeed, because overall suitable habitat is more fragmented and the NRM has higher human access than many places where wolves roam freely and are subject to harvest (e.g., Canada and AK), monitoring of wolf vital rates, along with concomitant conservation and management strategies directed at wolves, their habitat, and humans, will be important for ensuring long‐term viability of wolves in the region.

Wolf survival and population trend using non‐invasive capture–recapture techniques in the Western Alps

Summary1. Reliable estimates of population parameters are often necessary for conservation management but these are hard to obtain for elusive, rare and wide‐ranging species such as wolvesCanis lupus.This species has naturally recolonized parts of its former habitat in Western Europe; however, an accurate and cost‐effective method to assess population trend and survival has not been implemented yet.2. We used open‐model capture–recapture (CR) sampling with non‐invasive individual identifications derived from faecal genotyping to estimate survival and trend in abundance for wolves in the Western Alps between 1999 and 2006. Our sampling strategy reduced individual heterogeneity in recaptures, thus minimizing bias and increasing the precision of the estimates.3. Young wolves had lower apparent annual survival rates (0·24 ± 0·06) than adult wolves (0·82 ± 0·04); survival rates were lower in the summer than in the winter for both young and adults. The wolf population in the study area increased from 21 ± 9·6 wolves in 1999 to 47 ± 11·2 wolves in late winter 2005; the population growth rate (λ = 1·04 ± 0·27) was lower than that recorded for other recolonizing wolf populations.4. We found a positive trend in wolf abundance, regardless of the method used. However, the abundance estimate based on snow‐tracking was on average 36·2% (SD = 13·6%) lower than that from CR modelling, because young dispersing wolves are likely to have lower sign detection rates in snow‐track surveys, a problem adequately addressed by CR sampling.5. Synthesis and applications.We successfully implemented a new method to assess large carnivore population trend and survival at large spatial scales. These are the first such estimates for wolves in Italy and in the Alps and have important management implications. Our approach can be widely applied to broader spatial and temporal scales for other elusive and wide‐ranging species in Europe and elsewhere.

Social-Natural Landscape Reorganised: Swedish Forest-edge Farmers and Wolf Recovery

The politics and the underlying reasons behind the recovery of the Scandinavian wolf population are increasingly contested. According to official policy, wolves should be guaranteed a place in the Swedish natural world. However, the conflict over whether Sweden should host a wolf population sets views on biodiversity and sustainable development against the perspective that local traditions and livelihoods are threatened by the return of wolves. These diverging environmental visions can be seen as competing interests and understandings of nature and wildlife. The desire of the state and nature conservation organisations to implement measures to provide conditions fostering wolf survival are counterbalanced by local action groups and community residents struggling to maintain conditions for conserving summer pastures, opportunities for hunting with sporting dogs, and other recreational activities such as mushroom- and berry-picking. Not only are these activities considered to have high natural and cultural value, the European Union (EU) has stated that small-scale farming is important for maintaining the landscape and safeguarding the survival of values associated with 'agri-environmental' habitats. The conflict between the interest groups is essentially about the access to and use of environmental resources. Squeezed between policies safeguarding wolf populations, preventing cruelty to animals and implementing activities required by the EU agricultural programme, farmers in areas with resident wolf populations have come to take part in processes that may reinforce rural identity.

Trends, dynamics and resilience of an Ethiopian wolf population

AbstractFifteen years of monitoring in the Bale Mountains provide a valuable time series to better understand the dynamics of populations of the endangered Ethiopian wolf Canis simensis in the face of epizootics and increasing human pressure. Line‐transect counts in four study areas were used to identify trends in the local abundances of wolves, people, livestock and domestic dogs (a putative rabies reservoir). Estimates of wolf abundance were validated against total counts in prime wolf habitats, where two local populations decimated by rabies in the early 1990s had recovered fully by 2000. Growth appeared to be regulated by negative density dependence, but the rate of growth was unexpectedly low at reduced densities. Limitations to rapid growth, including an initial gap for which data were sparse, are discussed. In a poorer habitat, wolf abundance estimates were less reliable but indicated slight fluctuations without an overall trend. A local extinction was recorded in an area of marginal habitat. With this exception, trends in wolf abundances were unrelated to trends in the abundance of people, livestock or dogs. Rabies emerged as the main cause of decline for high‐density populations. The rapidly increasing livestock grazing pressure in Bale gives cause for concern, calling for further research on its impacts upon long‐term wolf survival.

Monte Carlo simulation of Alaska wolf survival

Alaskan wolves live in a harsh climate and are hunted intensively. Penna's biological aging code, using Monte Carlo methods, has been adapted to simulate wolf survival. It was run on the case in which hunting causes the disruption of wolves' social structure. Social disruption was shown to increase the number of deaths occurring at a given level of hunting. For high levels of social disruption, the population did not survive.