Journal of Wildlife Management最新文献

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.

The increase in the population of harbor seals (Phoca vitulina) in the Erimo region of Hokkaido, Japan, has coincided with rising fishery conflicts, affecting salmon setnets in particular. While seal-related fishery damage has been reported, quantitative evidence of seal predation on salmon has been lacking. The present study employed a finite mixture model clustering method to analyze seal feeding patterns. This analysis revealed 13 distinct clusters, with one cluster specifically characterized by salmon predation. This cluster consisted primarily of larger individuals who obtained most of their daily energy requirements from salmon. In such an environment, seals may learn of setnet structures and fish aggregation characteristics, potentially increasing their dependence on these artificial structures. However, many seals in the population were not feeding on salmon, and the findings demonstrate that only a specific subset of the population, characterized by larger body size and older age, has developed specialized feeding strategies centered on salmon predation at setnets. This adaptation to setnet environments has significant implications for both fishery management and seal conservation in the region.

The number of alien species has increased significantly in recent decades, but only a few become invasive, posing threats to biodiversity and human activities. However, the invasive potential of alien species might depend on environmental compatibility and local conditions. The Italian wall lizard (Podarcis siculus) has been introduced across Europe, North Africa, and North America, and its actual invasiveness varies by location. Detrimental impacts have been observed mainly on congeneric species, often due to competition or habitat overlap. Nevertheless, in some regions, including the United States, no evidence for spread and impact has been reported. On Gorgona Island, Italy, the Italian wall lizard was likely introduced accidentally around 2000 and has rapidly expanded. This study examined the colonization of the Italian wall lizard on Gorgona Island and its interaction with the native common wall lizard (P. muralis). Findings indicate the Italian wall lizard thrives in human-altered habitats, while the common wall lizard persists in natural areas. The spread of the Italian wall lizard appears to be driven by environmental conditions rather than inherent aggressiveness, aligning with patterns observed on other Mediterranean islands. Its expansion stalled between 2021 and 2024, suggesting habitat saturation, not competition, limits spread. The study warns against labeling the Italian wall lizard as uniformly invasive, advocating context-specific assessments to avoid misdirecting conservation resources.

The northern bobwhite (Colinus virginianus) has become regionally extirpated from the northern portion of its range. Translocation remains a promising population restoration technique; however, repopulating some locales near the northern periphery of their range via long-distance translocation may require fine-tuning of methods proven successful in other regions because of differences in environmental conditions and extended handling times. We evaluated reproductive effort to determine if northern bobwhite nest production, nest success, and fecundity following translocation were constrained by high post-release mortality and a truncated breeding season at release sites in the Mid-Atlantic region. We translocated 508 radio-collared bobwhites from northern Florida and southern Georgia to 4 sites on the eastern shore of Maryland and southern New Jersey, USA. We monitored bobwhites 2–7 times/week via radio-telemetry from early April through late September 2015–2018. We found support for a constrained founder effect germane to nest production, nest success, and overall fecundity. The site-specific proportion of translocated hens that produced ≥1 nest ranged from 0.200 (SE = 0.048) to 0.500 (SE = 0.158) nests/hen. Nest daily survival rate (DSR) was lower at the New Jersey sites than the Maryland sites, with site-specific DSR ranging from 0.878 (85% credible interval [CrI] = [0.820, 0.931]) to 0.972 (85% CrI = [0.947, 0.991]). The highest fecundity estimate across all sites and years was 3.23 (85% CrI = [2.70, 3.84]) female chicks per translocated adult female. Overall, nest production was low, which is inextricably linked to high post-release adult mortality and a truncated nesting season typical of northern latitudes and atypical of southern latitudes. Adjusting translocation stocking density rate (birds/ha) and release timing may maximize the number of birds alive during the peak of nesting season. Nest DSR was likely low because of predation associated with high meso-mammalian predator abundance. Overall fecundity was insufficient to facilitate population growth, illustrating the importance of refining and adapting existing translocation methodology based on regional climate and breeding opportunity heterogeneity. Vital rate estimates from this study coupled with other studies may guide future translocations within the Mid-Atlantic and provide perspective for translocation as a population restoration technique range-wide.

Numerous waterfowl species have altered their geographic distribution in recent decades. The greater white-fronted goose (Anser albifrons) has shifted its wintering distribution from coastal marshes in Texas and Louisiana, USA, to interior landscapes, creating challenges for conservation managers. Although the range shift has been primarily attributed to landscape-scale changes in rice production, effects of fine-scale habitat conditions on greater white-fronted goose habitat use are unknown. Thus, information on fine-scale environmental conditions could provide information to managers working to mitigate effects of the shift. We used global positioning system neck collars to monitor 78 greater white-fronted geese in Louisiana each winter during 2016–2019 and visited all used locations to record vegetation height, water depth, and land cover. We modeled greater white-fronted goose habitat use in 4 regions across Louisiana (central, coastal, north, southwest), and evaluated effects of vegetation height, water depth, land cover, and interactions. In our candidate model set, we included a sampling null, which accounted for differences in sampling frequencies among hunt seasons and diel periods. The top model in the central, coastal, and north regions included water depth, whereas the top model in the southwest region included water depth, vegetation height, and land cover. Parameter estimates and confidence intervals indicated that goose habitat use was higher at sites with >5.1 cm of water compared to dry sites or sites with <5.1 cm of water. In the southwest region, goose habitat use was highest in areas identified as other land cover (e.g., corn, cotton, rye, sugarcane) and lowest in open water. Although Louisiana has substantial anthropogenic food resources in the form of rice agriculture and abundant grazing opportunities afforded by mild winters, our results indicate that wet areas provide better habitat to greater white-fronted geese than dry areas. New agricultural flooding regimes in Louisiana could improve habitat quality and potentially mitigate some effects of the winter distribution shift.

Several initiatives have been launched over the past 20 years throughout Europe to explore practical ways to enhance biodiversity on farms; however, their effectiveness in preserving wildlife has been questioned, as they are mainly means-based approaches. Agri-environmental schemes, the instrument of choice of the Common Agricultural Policy to promote biodiversity with action-oriented payments, have also partially failed to achieve their desired results. As researchers are called upon to invest in the support, implementation, and acceleration of farms' transitions towards more biodiversity-sustainable systems, and in view of the limitations of these initiatives and other public policy instruments, we propose in this article to operationalize the concept of adaptive management. We tested a results-based approach to biodiversity management on a research farm located on the French Atlantic coast. Using a scientific approach, we describe the project design, including identification of several target species with their quantified objectives, development of dashboards, and design of a roadmap. We then discuss the major challenges encountered in implementing this approach to biodiversity goals, and how this type of results-based approach on private farms can be tested.

Populations of Attwater's prairie-chicken (Tympanuchus cupido attwateri), once widespread across the Gulf Coastal Prairies of North America, remain critically endangered. Lek counts of displaying males provide the primary basis for population monitoring, yet these counts are vulnerable to detection error and fail to capture underlying demographic processes. We applied hierarchical Bayesian N-mixture and Dail–Madsen models to 23 years of lek count data (2002–2024) from Attwater Prairie Chicken National Wildlife Refuge to estimate detection-adjusted abundance and population trend, and assess relationships between abundance, demographic rates, and responses to environmental drivers. The top-performing N-mixture model estimated a mean annual population growth rate of 3% (95% CRI: 1%, 5%), providing statistically supported evidence of a positive trend, whereas the naïve count-based estimate showed no significant change over time. Dail–Madsen models indicated recruitment, rather than survival, as the primary demographic constraint. Environmental covariates revealed that abundance peaked at intermediate levels of perennial forb and grass cover and under moderate drought conditions, with declines observed under vegetative overgrowth and excessive moisture. The interaction between precipitation and the median time since fire revealed that short median time since fire intervals were associated with greater abundance during normal to wet years, underscoring the importance of frequent prescribed fires (median 2- to 3-year intervals). These results provide the first detection-corrected trend estimates for this species and offer a model-based framework for linking weather, vegetation, and fire history with population dynamics. Our findings directly inform adaptive management strategies contributing to recovery for this species and demonstrate how robust analyses of long-term lek data enhance conservation decision-making for endangered grassland birds.

Reptiles, and turtles in particular, are disproportionately represented in the illegal wildlife trade. Chemical analysis of animal tissues is a powerful tool to combat wildlife laundering, which is the act of disguising animals poached from the wild as legally raised in captivity by means of counterfeit import or export documentation. We used stable isotope ratios and trace element concentrations derived from the claw tips of 449 wood (Glyptemys insculpta), spotted (Clemmys guttata), and Blanding's turtles (Emydoidea blandingii) from the eastern United States to develop a multispecies statistical model for determining the probability that a confiscated turtle was poached from the wild. During model development, our simple model that used 4 stable isotope ratios (δ¹³C, δ¹⁵N, δ¹⁸O, δ²H) and 4 trace elements (Ti-47, Fe-57, Cu-63, Ba-137) misclassified only 2 turtles out of 449, yielding a predictive accuracy rate of 99.55%. We further validated the predictive accuracy of our multispecies model by calculating the probability of being wild for 9 eastern box turtles (Terrapene carolina) and a replicate sample of 5 wood turtles, all with known classifications of being wild or captive. We now aim to promote our model to aid conservation law enforcement in combating the illegal turtle trade by helping to close the wildlife laundering loophole. We also hope to provide a forensic framework for developing a conservation tool for other taxa of conservation interest.