Human-caused Mortality Research Articles

The effects of human-caused mortality on mammalian cooperative breeders: a synthesis.

Human-caused mortality can be pervasive and even highly selective for individuals in groups of cooperative breeders. Many studies of cooperative breeders, however, do not address human-caused mortality. Similarly, studies focused on the effects of human-caused mortality on wildlife populations often do not consider the ecology of cooperative breeders. We searched the literature and identified 58 studies where human-caused mortality affected a group characteristic, vital rate, or population state of a cooperative breeder. Of studies reporting population growth or decline, 80% reported a link between human-caused mortality and population declines in cooperative breeders. Such studies often did not identify the mechanism behind population declines, but 28% identified concurrent declines in adult survival and another 21% reported concurrent declines in recruitment or reproduction. There was little overlap between the cooperative breeding and human-caused mortality literatures, limiting our ability to accrue knowledge. Future work would be beneficial if it (i) identified the vital rate(s) causing population declines, (ii) leveraged management actions such as lethal removal to ask questions about the ecology of group-living in cooperative breeders, and (iii) used insights from cooperative breeding theory to inform management actions and conservation of group-living species.

Climate change introduces threatened killer whale populations and conservation challenges to the Arctic.

The Arctic is the fastest-warming region on the planet, and the lengthening ice-free season is opening Arctic waters to sub-Arctic species such as the killer whale (Orcinus orca). As apex predators, killer whales can cause significant ecosystem-scale changes. Setting conservation priorities for killer whales and their Arctic prey species requires knowledge of their evolutionary history and demographic trajectory. Using whole-genome resequencing of 24 killer whales sampled in the northwest Atlantic, we first explored the population structure and demographic history of Arctic killer whales. To better understand the broader geographic relationship of these Arctic killer whales to other populations, we compared them to a globally sampled dataset. Finally, we assessed threats to Arctic killer whales due to anthropogenic harvest by reviewing the peer-reviewed and gray literature. We found that there are two highly genetically distinct, non-interbreeding populations of killer whales using the eastern Canadian Arctic. These populations appear to be as genetically different from each other as are ecotypes described elsewhere in the killer whale range; however, our data cannot speak to ecological differences between these populations. One population is newly identified as globally genetically distinct, and the second is genetically similar to individuals sampled from Greenland. The effective sizes of both populations recently declined, and both appear vulnerable to inbreeding and reduced adaptive potential. Our survey of human-caused mortalities suggests that harvest poses an ongoing threat to both populations. The dynamic Arctic environment complicates conservation and management efforts, with killer whales adding top-down pressure on Arctic food webs crucial to northern communities' social and economic well-being. While killer whales represent a conservation priority, they also complicate decisions surrounding wildlife conservation and resource management in the Arctic amid the effects of climate change.

The glaring gaps: environmental violence and peace research and practice

ABSTRACT Human-caused global impact on socio-ecological systems has been labelled the greatest challenge to human and environmental health. It is also a significant, and perhaps the greatest threat to global peace. Restricting peace research to direct violence alone causes a glaring gap in peace research and practice between different forms of human-caused mortality and suffering. Explicitly accounting for Environmental Violence can offer a critical component for building positive peace. This paper seeks to address what I consider to be strategic gaps that require the integration of multi-disciplinary research, intersectional peacebuilding practice, and concerted policy proposals. The four gaps are (1) failure to include environmental violence in peace research; (2) the multi- and trans-disciplinary gap; (3) the gap of scale and thinking in systems; and (4) failure in the specification of the harm and power differentials in contribution to and realisation of environmental risk. Generative pathways to reconcile these gaps are identified and explored.

Effects of lethal management on gray wolf pack persistence and reproduction in Wisconsin, USA.

Direct human-caused mortality accounts for about half of all large mammal mortality in North America. For social species like gray wolves (Canis lupus), the death of pack members can disrupt pack structure and cause pack dissolution, and mortality of breeding adults or wolves during reproduction and pup-rearing can decrease pup recruitment. We estimated minimum and maximum probability of wolf pack persistence in Wisconsin, USA, during biological years (15 April-14 April) 2011-2019 and evaluated the influence of pack size and legal harvest mortality on pack persistence during 2012-2014. Harvests comprised 75-161 mortalities within 194 monitored packs during 2012-2014, with 56-74% of packs having no wolves harvested each year. As an index of reproduction during 2013-2019, we also estimated the proportion of packs where pups responded to howl surveys. We evaluated the influence of pack size, legal harvest, and agency removal on reproduction during 2013-2015. Annual maximum pack persistence probability was uniformly high (0.95-1.00), and annual minimum pack persistence probability ranged from 0.86-0.98 with a possible decline during years of harvest. Reproduction was similar in years following harvest and agency removal (2013-2015, pup response = 0.27-0.40), and years without harvest or agency removal the year prior (2016-2019, pup response = 0.28-0.66). Pack size had a positive effect on pack persistence and reproduction. Total number of wolf mortalities and number of adult male and females removed did not influence pack persistence or reproduction. We suggest that low per-pack mortality, timing of harvest and agency removal, and harvest characteristics during 2012-2014 supported stable pack persistence and reproduction.

New threats in the recovery of large carnivores inhabiting human-modified landscapes: the case of the Cantabrian brown bear (Ursus arctos)

Understanding mortality causes is important for the conservation of endangered species, especially in small and isolated populations inhabiting anthropized landscapes where both natural and human-caused mortality may hinder the conservation of these species. We investigated the mortality causes of 53 free-ranging brown bears (Ursus arctos) found dead between 1998 and 2023 in the Cantabrian Mountains (northwestern Spain), a highly human-modified region where bears are currently recovering after being critically threatened in the last century. We detected natural traumatic injuries in 52.63% and infectious diseases in 39.47% of the 38 bears for which the mortality causes were registered, with 21.05% of these cases presenting signs of both infectious diseases and traumas. More specifically, almost 30% of the bears died during or after intraspecific fights, including sexually selected infanticide (10.53%). In addition, primary infectious diseases such as infectious canine hepatitis, distemper, clostridiosis and colibacillosis caused the death of 15.79% of the bears. The number of direct human-caused deaths (i.e., shooting, poisoning, snare) decreased over the study period. This study also reveals three new mortality causes triggered by pathogens, two of which—Clostridium novyi and verotoxigenic Escherichia coli—not previously described in ursids, and the other one, canine distemper virus, never reported in brown bears as cause of death. New management strategies for the conservation of Cantabrian bears, which are urgently needed due to the rapid expansion of the population, should consider the mortality causes described in this study and must promote further research to elucidate how the high prevalence of infectious diseases may threaten the current recovery of the population.

Using community science to advance grizzly bear conservation

Alberta grizzly bears are classified as a threatened species in the province of Alberta as of 2010, with human-caused mortality and habitat loss a primary threat. The people who live, work, and recreate within bear habitat play a crucial role in their conservation. While the public is often enthusiastic about grizzly bears, and opportunistically report their observations to government staff, these reports are not systematic or rigorously collected and lack key information. As such, we developed GrizzTracker as a community science program. Following several years of successful deployment, we analyzed community scientist data and evaluated the efficacy of the program through an online user survey. We found that the GrizzTracker app was useful as a data collection and public engagement tool, yielding information for applied management, and that community scientists were generally satisfied. We provide considerations for future program development, including considerations for human, social, technological, and financial capital investment related to design, development, and implementation of data collection protocols, the importance of clearly communicating outcomes, and opportunities for educational outreach. While there is continued trepidation by traditionally trained scientists to develop or engage in community science programs, and some noted areas of improvement for our program specifically, we think that GrizzTracker offers a success story in community science.

Fear of large carnivores amplifies human-caused mortality for mesopredators

The challenge that large carnivores face in coexisting with humans calls into question their ability to carry out critical ecosystem functions such as mesopredator suppression outside protected areas. In this study, we examined the movements and fates of mesopredators and large carnivores across rural landscapes characterized by substantial human influences. Mesopredators shifted their movements toward areas with twofold-greater human influence in regions occupied by large carnivores, indicating that they perceived humans to be less of a threat. However, rather than shielding mesopredators, human-caused mortality was more than three times higher than large carnivore-caused mortality. Mesopredator suppression by apex predators may thus be amplified, rather than dampened, outside protected areas, because fear of large carnivores drives mesopredators into areas of even greater risk from human super predators.

Demographics of Gray Wolf (Canis lupus) Packs Recolonizing Variable Habitats in Central Wisconsin

Some Canis lupus (Gray Wolf, hereafter Wolf) live in disjunct populations including Wisconsin's Central Forest Region (CFR), recolonizing there in the early 1990s. We examined how habitat factors and period of initial recolonization facilitated successful re-establishment of Wolves to this region. We divided this event into 3 periods: early (1994–1999), middle (2000–2005), and late (2006–2012). We defined habitat classes of individual pack territories as optimal, mixed, and marginal, based on: (1) percent public land, (2) percent agricultural land, and (3) road density. We analyzed the influence of time and habitat classes on pack territory size, winter pack size, pup presence, Wolf–human conflicts, human-caused Wolf mortalities, territory persistence, and reproductive performance. Pack demographics were similar across time, except pup presence was slightly lower during the middle period. Wolf–human conflicts increased over time and were correlated with population growth. Packs in marginal habitat were smaller in winter, exhibited lower reproductive performance, had more conflicts with humans, and experienced human-caused mortalities at rates 4 and 7 times higher than mixed and optimal habitats, respectively. We demonstrate that Gray Wolves tolerate some level of human-altered landscapes and identify demographic parameters that impact the Wolves' ability to survive in human-dominated landscapes.

The ecology of human-caused mortality for a protected large carnivore

Mitigating human-caused mortality for large carnivores is a pressing global challenge for wildlife conservation. However, mortality is almost exclusively studied at local (within-population) scales creating a mismatch between our understanding of risk and the spatial extent most relevant to conservation and management of wide-ranging species. Here, we quantified mortality for 590 radio-collared mountain lions statewide across their distribution in California to identify drivers of human-caused mortality and investigate whether human-caused mortality is additive or compensatory. Human-caused mortality, primarily from conflict management and vehicles, exceeded natural mortality despite mountain lions being protected from hunting. Our data indicate that human-caused mortality is additive to natural mortality as population-level survival decreased as a function of increasing human-caused mortality and natural mortality did not decrease with increased human-caused mortality. Mortality risk increased for mountain lions closer to rural development and decreased in areas with higher proportions of citizens voting to support environmental initiatives. Thus, the presence of human infrastructure and variation in the mindset of humans sharing landscapes with mountain lions appear to be primary drivers of risk. We show that human-caused mortality can reduce population-level survival of large carnivores across large spatial scales, even when they are protected from hunting.

Trend in aerial counts of beluga or white whales (Delphinapterus leucas) in Bristol Bay, Alaska, 1993-2005

Thirty-eight aerial surveys of beluga or white whales (Delphinapterus leucas) were conducted in Bristol Bay, Alaska, during six different years between 1993 and 2005. Belugas were sighted mainly close to shore in the upper parts of Nushagak and Kvichak bays, as well as along the coast between these bays and in the lower parts of major rivers. Data from 28 complete counts made in good or excellent survey conditions were analysed for trend. Counts ranged from 264 to 1,067. The estimated rate of increase over the 12-year period was 4.8%/year (95% CI = 2.1%-7.5%). Such a rate of increase suggests that either the population was below the environmental carrying capacity in the early 1990s or, alternatively, that factors that had been limiting population increase were alleviated after that time. A review of possible changes in human-caused mortality, predation and prey availability did not reveal a single likely cause of the increase. Among the factors that could have played a role are recovery from research kills in the 1960s, a modest decline in subsistence removals and a delayed response to increases in Pacific salmon (Oncorhynchus spp.) abundance in the 1980s. The positive growth rate for this population shows that in recent years there has been no substantial negative impact of human or natural factors, acting either alone or in combination, and there is no need for changes to the current management regime

Influence of anthropogenic activities on marine mammal strandings in the estuary and northwestern Gulf of St. Lawrence, Quebec, Canada, 1994–2008

Stranding records have long been used to monitor marine mammal mortalities and to help identify threats to populations. In coastal areas, marinemammals face numerous anthropogenic threats such as marine traffic and commercial fishing. The objective of this study was to investigate marinemammal stranding records from the St. Lawrence Estuary (SLE) and the northwestern Gulf of St. Lawrence (NWGSL), Quebec, Canada from 1994to 2008 for evidence of anthropogenic trauma caused by entanglement in fishing gear, ship collisions and gunshots. Of 1,590 marine mammalstranding records, 12% (n = 192) had evidence of anthropogenic trauma, most incidents being reported during summer when activities such asmarine traffic, most commercial fishing and recreational boating, occurred and a greater number of species were present in the area. These incidentswere classified into five categories (Incidental catch, Ship collision, Severe injury, Gunshot, Other). There were 1,245 mortalities and observationson carcasses suggested that anthropogenic trauma led to the death of 11% (141/1,245) of marine mammals: 14% (87/627) of cetaceans and 9%(54/618) of seals. Mortality of seals due to anthropogenic trauma was low, involving mainly Gunshot for grey (26% or 8/31) and harbour seals(26% or 8/31). Over the study period, marine mammal incidents with evidence of anthropogenic trauma increased significantly, driven by an increasein Incidental catch for two mysticete species, the common minke whale, 42% (39/92) and humpback whale, 13% (12/92) and Other for harbourporpoise 67% (16/24). Ship collision was the most common anthropogenic trauma for fin whales (22% or 8/36) and SLE beluga5 (22% or 8/36).Severe injury was reported for 22% (2/9) of small cetaceans and 78% (7/9) of seals. Evidence from some harbour porpoise stranding records(categorised as Other) suggests illegal hunting, incidental catch, predation or scavenging by grey seals in a marine protected area. The observedincrease in Incidental catch of common minke and humpback whales may be due to: (1) a shift in distribution of these two species into the SLE andNWGSL, possibly related to changes in the ecosystem; (2) changes in fishery practices; and (3) an increase in detection of marine mammal strandings.Anthropogenic trauma affecting marine mammals was documented including some species at risk, such as the harbour porpoise, the St. LawrenceEstuary beluga population, blue and North Atlantic right whales, in the St. Lawrence ecosystem including in a marine protected area. This studydemonstrates the usefulness of stranding records in helping to monitor human-caused mortality in marine mammal populations.

Reported mortality of Griffon VultureGyps fulvusin central Italy and indications for conservation and management

SummaryVultures are long-lived species sensitive to human-caused mortality that has already determined a widespread collapse in Asian and African populations. They provide significant ecosystem services (regulatory and cultural) consuming livestock carcasses and saving greenhouse gas emissions, favouring nutrient recycling, environmental sanitation, and providing financial revenue. Appraising the incidence and causes of mortality could help to improve management and conservation actions. We compiled records of reported mortalities for the reintroduced Griffon VultureGyps fulvuspopulation of the central Apennines in Italy (123 cases, July 1994–December 2020). The average mortality was 4.69 vultures per year (± 1.14 SE), with no significant temporal trend. The peak of mortality events, estimated by harmonic regression analysis, was in March, while the minimum occurred in October. No differences were found among age classes and sex ratio mortality was established at 1.43:1 (M:F,N= 68). Out of 103 (83.7%) vultures which underwent a post-mortem and toxicological screening, 53% were poisoned, mainly by carbamates, and 27% died of unknown causes. Overall, direct or indirect anthropogenic mortality caused 67% of deaths. Even considering an inherent bias associated with reported mortality as to the prevalence of causes of death and estimation of mortality rates, the overwhelming relevance of poisoning highlights that existing anti-poisoning efforts should be refined and incorporated into a coordinated multidisciplinary strategy. A standardised approach, from vulture carcass discovery to post-mortem procedures and toxicological analysis, should be applied to reduce uncertainty in the determination of causes of death, increasing effectiveness in the prosecution of wildlife crimes. As most of the poisoning cases affecting the Griffon Vulture population in the central Apennines likely represent a side (though illegal) effect of retaliatory efforts to defeat livestock predators, effective strategies in reducing human–wildlife conflicts should be applied.

Status and Conservation of the Saker Falcon in Austria

The short lecture summarizes the results of a conservation program for the Saker Falcon (Falco cherrug) in Austria for the years 2011–2022. The species reaches the western limit of its global distribution in Austria. Therefore, it is restricted to the east of the country and naturally a scarce species with high conservation concern. When Saker Falcons showed a growing tendency to nest in abandoned corvid nests on high-voltage power lines from the late 1990s on, the Austrian Ornithological Center (AOC, formerly Vetmeduni) and Austrian Power Grid (APG) supported the species from 2007 onward by providing artificial nesting sites on several powerlines within the known breeding range. AOC and BirdLife Austria have been conducting a joint nation-wide conservation program since 2011. This includes a yearly survey of all known breeding sites, ringing Saker chicks (carried out since 2015), and monitoring reasons for mortality and potential threats. Within the surveyed period (2011–2022), the species showed a clear increase in breeding pairs, successfully breeding pairs, and fledged young per breeding attempt. The clearly positive trend in all population parameters surveyed may be attributed to several factors such as nest site availability, nest site selection, and changing weather conditions. The number of artificial nesting sites has been increased; while the conservation program began with the installation of breeding platforms, from 2014 on all additionally installed artificial aids have been nest boxes. Since then, we have observed a steep increase in the number of pairs breeding in these boxes, which most probably contributed to the population growth as well as the rising proportion of successfully breeding pairs. Despite the prospering population, the breeding range of the species has not increased significantly and is still limited to the low-lying Pannonian region in eastern Austria. Contrary to other recovering raptor species in the region (e.g. Imperial Eagle Aquila heliaca and Red Kite Milvus milvus), no clear westward expansion of the Saker’s range could be observed. Rather a rising concentration of pairs in the long-known range led to population growth. Interestingly, the most westerly historic breeding sites on the edge of the Alps and of the Bohemian Massif have been abandoned for decades. The Pannonian basin hosts a single transboundary population of Saker Falcon and the birds move regularly between the different countries. This is also true for the Austrian part of the range: Most recoveries of banded Austrian birds have been made abroad and prove the exchange of birds between Austria, Slovakia, Hungary, and Serbia. Other interesting records of Austrian ringed birds comprise a recovery from Algeria and one from Poland. Currently, we know of no threats impacting the Saker Falcon in Austria on the population level. Nevertheless, our results show some potential threats that must be closely monitored in the future to secure the species. Proven, human-caused mortality reasons comprise collisions with power line infrastructure, wind power plants and vehicles, electrocution, and deliberate shooting. Intentional as well as unintentional poisoning is highly likely to occur at least occasionally but has not yet been investigated thoroughly. Our results give rise to several research topics that should be considered in the future, including the influence of wind power development, possible nest site competition between Eagle Owl (Bubo bubo) or Northern Raven (Corvus corax) and Saker Falcon or the effects of sublethal rodenticide poisoning on the bird’s health and mortality risk.

Survival of a small reintroduced griffon vulture population in the Apennines: Insights from Global Positioning System tracking

Conservation translocations ( e. g., restocking, reintroductions) represent efficient tools to prevent the extinction or favouring the return of previously extirpated populations into the wild. Evaluating demographic parameters of translocated populations is a key issue to assess and monitor their conservation status and to provide evidences useful to implement management actions aimed at long-term conservation results. We report first data on survival estimates and related mortality causes for a reintroduced population of Eurasian griffon vultures ( Gyps fulvus) in the central-southern Apennine, Italy, from satellite telemetry data. Twenty vultures have been fitted with solar-powered Global Positioning System (GPS) tags in Pollino National Park (PNP, southern Italy, N = 9) and Monte Velino Reserve (MVR, central Italy, N = 11). Survival has been estimated on a total amount of 173,568 GPS fixes from December 2016 to October 2020 (1415 days) using the Fleming-Harrington estimator. Five, out of 20 vultures, died by poisoning (40%), collision with wind turbines (20%) and of unknown causes (40%). Two birds dispersed from MVR to France (though they later came back) and one from PNP to Croatia. Estimated survival rate across the whole study period was 0.709 (±0.11, SE; 0.523–0.961, 95% CI), and annual survival rate was 0.915 (±0.06, SE; 0.846–0.990, 95% CI). No significant differences in survival rates have been detected according to sex or age. As mortality in our study was mainly human-caused, we urge relevant institutions and agencies to strengthen and effectively establish anti-poison strategies, as well as implementing mitigation and prevention measures for the existing and planned wind farms. The establishment of a long-term viable population in the central-southern Apennines will depend upon both lower levels of human-caused mortality and habitat preservation.

Protection status, human disturbance, snow cover and trapping drive density of a declining wolverine population in the Canadian Rocky Mountains

Protected areas are important in species conservation, but high rates of human-caused mortality outside their borders and increasing popularity for recreation can negatively affect wildlife populations. We quantified wolverine (Gulo gulo) population trends from 2011 to 2020 in > 14,000 km2 protected and non-protected habitat in southwestern Canada. We conducted wolverine and multi-species surveys using non-invasive DNA and remote camera-based methods. We developed Bayesian integrated models combining spatial capture-recapture data of marked and unmarked individuals with occupancy data. Wolverine density and occupancy declined by 39%, with an annual population growth rate of 0.925. Density within protected areas was 3 times higher than outside and declined between 2011 (3.6 wolverines/1000 km2) and 2020 (2.1 wolverines/1000 km2). Wolverine density and detection probability increased with snow cover and decreased near development. Detection probability also decreased with human recreational activity. The annual harvest rate of ≥ 13% was above the maximum sustainable rate. We conclude that humans negatively affected the population through direct mortality, sub-lethal effects and habitat impacts. Our study exemplifies the need to monitor population trends for species at risk—within and between protected areas—as steep declines can occur unnoticed if key conservation concerns are not identified and addressed.

Identifying human-caused mortality hotspots to inform human-wildlife conflict mitigation

Humans are responsible for over a quarter of all wildlife mortality events across the globe. The pressure this puts on wildlife populations contributes to the decline of many at-risk species. To minimize human-caused mortality and reverse population declines in species across the world, we first need to know where these events are happening or likely to occur since managers and public agencies often have limited resources to devote to a problem. As such, our objective was to develop a modeling approach to delineate human-caused wildlife mortality hotspots in regions with limited data. We used internet search engines and national media to collect data on brown bear ( Ursus arctos ) mortality events in Iran from 2004 to 2019. We then developed a spatially-explicit Maximum Entropy (MaxEnt) model using anthropogenic and environmental variables to predict the probability of human-caused brown bear mortality. We were able to delineate 7000 km 2 as human-caused mortality hotspots, along with the geographical locations of those hotspots. This provides information that can help identify where critical conflict mitigation efforts need to be implemented to reduce the potential for human-caused wildlife mortality. However, more targeted studies such as surveys of local people will be needed inside hotspots identified with this methodology to assess the attitudes of humans toward different wildlife species, informing the specific mitigation actions that will need to be made. Finally, we suggest that media data can be used to identify these hotspots in regions where systematic data is lacking.

Harvest and density‐dependent predation drive long‐term population decline in a northern ungulate

The relative effect of top‐down versus bottom‐up forces in regulating and limiting wildlife populations is an important theme in ecology. Untangling these effects is critical for a basic understanding of trophic dynamics and effective management. We examined the drivers of moose (Alces alces) population growth by integrating two independent sources of observations within a hierarchical Bayesian population model. We used one of the largest existing spatiotemporal data sets on ungulate population dynamics globally. We documented a 20% population decline over the period examined. There was negative density‐dependent population growth of moose. Although we could not determine the mechanisms producing density‐dependent suppression of population growth, the relatively low densities at which we documented moose populations suggested it could be due to density‐dependent predation. Predation primarily limited population growth, except at low density, where it was regulating. After we simulated several harvest scenarios, it appeared that harvest was largely additive and likely contributed to population declines. Our results highlight how population dynamics are context dependent and vary strongly across gradients in climate, forest type, and predator abundance. These results help clarify long‐standing questions in population ecology and highlight the complex relationships between natural and human‐caused mortality in driving ungulate population dynamics.

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.

Larger females have more calves: influence of maternal body length on fecundity in North Atlantic right whales

North Atlantic right whales (NARW) are critically endangered and have been declining in abundance since 2011. In the past decade, human-caused mortalities from vessel strikes and entanglements have been increasing, while birth rates in the population are at a 40 yr low. In addition to declining abundance, recent studies have shown that NARW length-at-age is decreasing due to the energetic impacts of sub-lethal entanglements, and that the body condition of the population is poorer than closely related southern right whales. We examined whether shorter body lengths are associated with reduced fecundity in female NARW. We compared age-corrected, modeled metrics of body length with 3 metrics of fecundity: age at first reproduction, average inter-birth interval, and the number of calves produced per potential reproductive year. We found that body length is significantly related to birth interval and calves produced per reproductive year, but not age at first reproduction. Larger whales had shorter inter-birth intervals and produced more calves per potential reproductive year. Larger whales also had higher lifetime calf production, but this was a result of larger whales having longer potential reproductive spans, as body lengths have generally been declining over the past 40 yr. Declining body sizes are a potential contributor to low birth rates over the past decade. Efforts to reduce entanglements and vessel strikes could help maintain population viability by increasing fecundity and improving resiliency of the population to other anthropogenic and climate impacts.

Potential Futures for Coastal Wolves and Their Ecosystem Services in Alaska, With Implications for Management of a Social-Ecological System

Carnivores across much of the world are declining, leading to loss of biodiversity as well as the ecosystem services carnivores provide. In 2020, the Alexander Archipelago (AA) wolf was petitioned for protection under the U.S. Endangered Species Act (ESA) for the third time in 30 years. Concerns included habitat alteration from industrial timber harvest and subsequent declines in prey (deer), human-caused mortality, climate change, and genetic inbreeding. However, the underlying biogeography and ecology of these wolves continues to suggest resiliency across the subspecies’ range, even though local populations may go extinct. If local wolf populations go extinct, it will result in loss of their ecosystem services (e.g., interactions of wolves with their prey, which prevents over-browsing and protects carbon sequestration in soils and trees), which will likely have major consequences for the local social-ecological system. Here, we updated a model we constructed for the last ESA listing process (2015) to examine the dynamics of wolf and deer populations on Prince of Wales Island (the primary geographic focus of all three petitions) in response to future environmental and management scenarios developed with stakeholders. Further, we considered how changes in deer abundance impact predation services (prevention of over-browsing by deer). We found that wolf populations generally persisted over 30 years, but dropped below an effective population size of 50 wolves in 10–98% of years simulated. Low wolf abundance resulted in higher deer abundance, which increased hunting opportunity, but also browsing damages (e.g., 19% of areas would be over-browsed if wolf harvest caps are removed, and >30% of areas would be over-browsed if wolves go extinct). Human harvest of wildlife was a key regulator of abundance and ecosystem services within the coastal rainforest social-ecological system; wolf abundance was most affected by wolf harvest regulations; and deer harvest restrictions increased wolf and deer abundances, but also greatly increased browsing impacts (>70% of areas heavily browsed if hunting ceased). Our findings support an integrated approach to management of this social-ecological system, such that social and ecological sciences are both used to monitor important components of the system (e.g., measuring public sentiment and likelihood of poaching, alongside wolf and deer numbers). Integration and adaptive approaches are needed to ensure that the many ecosystem services humans depend on are valued, conserved, and restored, including the cryptic predation services wolves have historically provided to the timber industry via reduced browsing pressure by deer.