Journal of Wildlife Management最新文献

The Mexican wolf (Canis lupus baileyi) is a keystone subspecies of the southwestern United States and northern Mexico. Its ecological role, long lost, is slowly being reinstated. Reintroduction programs are being implemented and high-quality habitat capable of sustaining populations of this species has been identified in both the United States and Mexico. However, the availability of adequate prey biomass to support recovery of Mexican wolves has not been directly estimated. We estimated the potential ecological carrying capacity for the Mexican wolf based exclusively on ungulate prey biomass using density estimates derived from camera trap surveys conducted between 2017 and 2019 in high-quality areas within the species’ historical distribution. Results indicate adequate prey for the recovery of Mexican wolves within high-quality habitat. In the United States, the potential density estimate is high (21.4–52.7 wolves/1,000 km²) because of the presence and relatively high densities of 3 ungulates: elk (Cervus canadensis), mule deer (Odocoileus hemionus), and white-tailed deer (Odocoileus virginianus). In Mexico, density estimation varies 5.2–14.3 wolves/1,000 km², with only one ungulate species available as prey, white-tailed deer. Our calculations are underestimates of wolf carrying capacity because they are based on only ungulate prey, and Mexican wolves are known to have a more diverse diet of smaller prey compared to wolves in northern climes. In both countries, recovery goals for this subspecies appear achievable, with the potential of approximately 1,230–3,100 wolves in high-quality habitat. Currently, there are 2 reintroduction areas, one in the southwestern United States and one in northern Chihuahua, Mexico. We found that the southern Sierra Madre Occidental, specifically the high-quality patch in the state of Durango, could be considered as a second reintroduction site in Mexico. Estimations of potential carrying capacity for carnivores, particularly those proposed for reintroduction, are a crucial step in the conservation planning process and in setting achievable objectives.

The Qinghai-Tibet Plateau (QTP), a global biodiversity hotspot, exemplifies both the achievements and challenges of China's development paradigm that considers both environmental protection and socioeconomic progress. While conservation policies have facilitated wildlife population recovery across the QTP, they have also intensified human–wildlife conflicts, particularly with gray wolves (Canis lupus), posing new challenges for biodiversity conservation. Although wolf-human conflicts have been extensively studied worldwide, critical gaps persist regarding the influence of large-scale conservation policies in Asian high-altitude ecosystems and the specific socioeconomic and ecological drivers of wolf-human conflicts in protected areas following recovery of wolf populations. This study addressed these gaps by analyzing household socioeconomic data and ecological variables from the Tao River National Nature Reserve in the eastern QTP. Using a mixed-methods approach combining questionnaire surveys and semi-structured interviews, we surveyed 150 households across 41 settlements and 14 survey points, obtaining 142 valid responses. Binary logistic regression and hierarchical partitioning analyses identified key factors influencing whether respondents or their livestock would be attacked or harassed by wolves. Results showed that wolf conflict risk increases with distance to guard station and declining grassland quality. Households highly dependent on grazing income, lacking migrant work experience, with an increased number of livestock, and with lower annual household incomes were most vulnerable. Grazing income (with an influence weight of 20.67%), changes in livestock number (16.34%), and migrant work experience (6.60%) were the primary conflict drivers. We propose integrated mitigation strategies including risk-based grazing management, compensation schemes, protective husbandry practices, livelihood diversification, and community-based monitoring to foster human–wildlife coexistence and support sustainable ecosystem management in the QTP.

A common approach to monitoring bear populations is the estimation of population sizes through non-invasive DNA sampling by means of hair snags. Although successful in acquiring population size estimates, genetic capture-recapture-based population surveys lack provision of the demographic parameters needed to inform a multi-dimensional understanding of a population. We hypothesized that grizzly bear (Ursus arctos) hair hormone concentrations could be used to determine key demographic parameters, specifically whether animals were male or female, sub-adult or adult, pregnant or non-pregnant females, lactating or non-lactating females, and females with or without cubs. We measured hormone profiles (16 steroid and thyroid hormones relating to reproduction, stress, and nutrition) from 130 grizzly bear hair samples collected during live-capture events in Alberta, Canada, from 2008-2019, for which we were able to determine sex, age class, and several measures of reproductive status in females (pregnancy, lactation, and presence of cubs). We used random forest models to predict demographic parameters based on different combinations of hormone values, with a predictive accuracy ranging from 53% to 94%. Our best performing models were those developed to predict sex (80% accuracy when applied to all bears and 94% accuracy when subset to adult bears). Age class models performed better on male bears (86% accuracy) than on female bears (73% accuracy). Our analyses of female reproductive status were constrained by sample size limitations but resulted in a predictive model able to determine whether an adult female was accompanied by cubs of the year with 66% accuracy. By testing this methodology on hair samples collected from captured grizzly bears where these demographic parameters were known, we demonstrate its potential applicability to non-invasive monitoring approaches. Pairing hair hormone concentration analysis with genetic capture-recapture surveys has the potential to provide multi-dimensional population data to wildlife managers, better informing evidence-based decisions.

Conflicts between native predators and endangered species pose significant challenges for conservation. The piping plover (Charadrius melodus) is a migratory shorebird that breeds in 3 regions of North America. The Great Lakes population, the smallest of the 3, is federally endangered and had only 86 breeding pairs in 2025. This population faces various conservation challenges, including predation by merlins (Falco columbarius). We evaluated the potential effectiveness of merlin translocation as a non-lethal method to reduce predation on piping plovers. We captured and translocated 33 merlins during the 2023 and 2024 breeding seasons. Of these, 28 individuals were equipped with tracking devices to monitor their movements after being translocated 101–404 km from their capture sites. Our findings revealed that 42% of translocated merlins did not return to their capture locations within the same breeding season. We found that sex best explained variation in translocation outcome, followed by age and direction of translocation. Females, younger individuals, and birds translocated to the east were less likely to return. By contrast, translocation distance and season timing had little effect on returns. Although we observed variability in post-release movements, successfully translocated merlins exhibited delayed and more directional movements compared to those that returned. These results highlight the potential of predator translocation to alleviate predation pressure on endangered species, but challenges such as moderate success rate relative to cost and effort remain. We provide evidence-based recommendations for refining predator management strategies, emphasizing the importance of adaptive approaches to balance species recovery and ecosystem functionality.

The eastern spotted skunk (Spilogale putorius) is a small mesocarnivore that has experienced population decline across its range, whereas populations of the larger striped skunk (Mephitis mephitis) have remained stable. Both skunk species occur in Florida, USA, but their occupied ranges have diverged over time, with the range of the spotted skunk markedly declining. Determining their ecological niches within the framework of species distribution models (SDMs) can help to understand their habitat use and landscape-scale interactions in Florida. We developed SDMs for both species using the presence-only model Maxent, incorporating occurrences collected from 2017–2022 from community science and research data, along with 12 environmental variables representing various landscape features (e.g., land cover, topography, fire history). We quantified the area of predicted habitat for each species, estimated their spatial overlap, and measured potential impacts from external pressures (e.g., projected urbanization, sea level rise). Owing to their range decline and habitat specialization, we expected a smaller predicted area of habitat for eastern spotted skunk, with higher potential for external pressures and minimal overlap with striped skunk habitat. Our results indicated habitat area was smaller for eastern spotted skunk (24,333 km²) than striped skunk (31,964 km²), with minimal spatial overlap (14%). We found that eastern spotted skunk distribution occurred mostly in coastal and southern areas of Florida and was positively influenced by scrub-shrubland cover and vegetation diversity and negatively influenced by cropland and developed areas. Striped skunk distribution mostly occurred in northern and interior areas of Florida and was positively influenced by wooded edges, prairie, and wetland cover. Less-rugged topography was important to both species. Projected trends in urbanization and sea level rise more greatly threaten the habitats of eastern spotted skunk than striped skunk. We provide a detailed habitat map and a much-needed description of the ecological niche of the eastern spotted skunk in Florida, which differs from that of the striped skunk. Overall, this study can inform both statewide and species-wide conservation and management decisions for both skunk species.

Duckling survival is a major component of waterfowl productivity and is especially important in species like the American black duck (Anas rubripes), which has populations that are below the North American Waterfowl Management Plan goals. We captured and radio-marked 13 female black ducks and 39 ducklings during the 2020 and 2021 breeding seasons to quantify fine-scale breeding-season movements, habitat use, and duckling survival in coastal North Carolina, USA. The mean initial movement distance of marked broods from the nest was 490.02 m (95% CI = 329.45–650.59). Broods tended to use islands instead of brackish marsh mainlands and avoided open water in both land cover types. On a microhabitat scale, broods used areas with more litter, bare ground, and less water than available areas. The estimated daily survival rate of ducklings was 0.914 (95% CI = 0.88–0.93) based on the null model. The most plausible explanatory model indicated that survival improved with increased use of pools and creeks within coastal salt marshes and that ducklings of younger females had greater survival. Duckling production in coastal North Carolina would benefit from promoting isolated islands.