Journal of Wildlife Management最新文献

Accurate and precise estimates of fish age are crucial for calculating dynamic rate functions of a fishery that aid in making management decisions. Otoliths are often the preferred structure used when aging fish, as they typically provide accurate and precise age estimations. However, non-lethal alternatives need to be explored for when sacrificing specimens for age and growth data is not desired. Metrics of bias and precision are often compared to assess differences in aging structures, but the influence of reader experience and subjectivity on these metrics has not been well-studied. We assessed bias and precision between whole-viewed sagittal otoliths, scales, dorsal fin spines, and anal fin spines of Largemouth Bass Micropterus nigricans, and compared metrics of bias and precision between experienced and inexperienced readers. Inexperienced readers produced higher coefficient of variation values across nearly all structures compared to experienced readers. However, reader experience had a negligible influence on accuracy, which varied between structures. Our results indicate that incorporating quality control and training protocols into aging analysis could increase precision and decrease bias. Age estimations obtained from sectioned sagittal otoliths were the most precise and are recommended for aging analysis if sacrificing the specimen is acceptable. Age estimate precision from scales was similar to that from anal fin spines, but scales provided better accuracy. Therefore, we recommend the continued use of scales as non-lethal aging structures in Nebraska. It would be prudent for researchers in other regions to assess bias and accuracy limitations of aging structures from local Largemouth Bass fisheries to determine which structure best suits their purposes.

Vicuñas (Vicugna vicugna) and guanacos (Lama guanicoe) are the two species of wild South American camelids whose distributions range from Peru to northern Argentina and southern Peru to southern Argentina, respectively. Listed as critically endangered in the 1960s due to poaching, vicuña numbers had been gradually recovering; however, new concerns about population stability have arisen with recent observations of sarcoptic mange outbreaks in this species. Sarcoptic mange is an infectious skin disease caused by the microscopic burrowing mite, Sarcoptes scabiei, which infects nearly 150 mammalian species globally, including guanaco and vicuña. Wild camelid populations across Argentina, Bolivia, Chile, and Peru have been affected by sarcoptic mange, with the most severe outbreaks resulting in localized extirpation. Population declines have conservation and economic implications, as many local communities harvest vicuña and guanaco fiber for profit. We review the current literature on sarcoptic mange in wild camelids from Argentina, Bolivia, Chile, and Peru to establish a current state of knowledge on spatial prevalence, management, and therapeutics, and identify existing knowledge gaps. Critical next steps include 1) implementation of effective management strategies that limit the transmission of sarcoptic mange, 2) standardization of data collected during community capture (i.e., chaccu) events, 3) assessing the potential role of community captures in mite transmission, and 4) evaluation of treatment options and best practices for implementation. Further, there is a need for capacity building to improve disease diagnostics and surveillance in wild camelids. A multisectoral collaboration between governmental authorities, communities, academic institutions, and national and international organizations focusing on wild South American camelid conservation could contribute to building actions aimed at preventing future outbreaks and mitigating the current burden of sarcoptic mange disease.

As grazing activities continue to expand, it is essential to understand how wild carnivores coexist with livestock disturbance in human-dominated landscapes. Such information remains limited for the Qinghai-Tibet Plateau, where snow leopards (Panthera uncia), grey wolves (Canis lupus), and their primary wild prey, the ungulate bharal (Pseudois nayaur), share habitat with livestock. We investigated their spatial co-occurrence patterns using camera-trapping datasets from the Qomolangma National Nature Reserve (QNNR) in the Central Himalaya and a multi-species occupancy framework. Our results revealed widespread livestock presence across both sampling areas, including strictly protected zones. We found that snow leopards exhibited positive co-occurrence with bharal, while wolves showed a positive spatial association with livestock. The occupancy patterns were also markedly driven by topographic factors: although snow leopards, bharal, and livestock tended to occur at lower elevations, snow leopards and bharal were more likely to occupy steeper areas, whereas livestock and wolves favored flatter terrain. These findings suggest that despite extensive livestock presence, snow leopards maintained a strong spatial association with their primary wild prey in steep terrain. In contrast, wolves' preference for flatter areas coincided with livestock distribution, possibly exacerbating the risk of livestock depredation and subsequent human–wildlife conflicts. This study demonstrates distinct habitat use patterns among wild carnivores, ungulates, and livestock in the Himalaya. These patterns reveal potential hotspots of livestock depredation in the QNNR and underscore grazing restriction as a key conservation strategy for fostering human–carnivore coexistence in the Qinghai-Tibet Plateau.

Grizzly bear (Ursus arctos) feeding on migratory army cutworm moths (Euxoa auxiliaris) was first documented by the Interagency Grizzly Bear Study Team (IGBST) during the early 1980s in the southeastern portion of the Greater Yellowstone Ecosystem (GYE). Since those initial observations, use of this seasonally available food resource by grizzly bears has grown substantially. As of 2023, we have documented 4,754 observations of grizzly bears feeding or digging at high-elevation talus slopes. We used those records to identify 36 unique moth sites in the GYE, assessed geographic characteristics of these sites, and documented chronology and frequency of use by grizzly bears. We used occurrences of radio-collared grizzly bears to identify a sample of bears that foraged at moth sites and investigated characteristics of fidelity, duration, diel activity, and movement patterns. Grizzly bears exhibited high fidelity to specific moth sites within and across years. Bears showed approximately 50% reductions in movement metrics while using sites, albeit with increased activity patterns. Estimates of feeding metrics by females exceeded those of males in intensity and duration of both use and daily activity. Given increasing human impacts and interest in observing this feeding interaction, quantifying metrics that describe the spatial and temporal patterns of moth site use by grizzly bears could be beneficial for future management. Further analyses are needed to fully examine the relationship between caloric influences of moth use on grizzly bear demographic rates.

Once extirpated from most of its range because of overharvest and habitat loss in the early 1900s, the eastern wild turkey (Meleagris gallopavo silvestris) has been recolonizing landscapes in the eastern United States following restoration and reintroduction efforts. Wild turkey populations have rebounded in the last 50 years, and the wild turkey is now seen as one of the most successful conservation efforts in the United States. More recently, wild turkeys have begun to expand into cities across the United States. While this can be seen as a successful return of a once-extirpated species, it has also given rise to human–wildlife conflict in highly populated areas. Given the ecological differences between urban and rural ecosystems, it is important for conservation and management efforts to understand how wild turkeys use urban landscapes. We used cameras deployed at 75 long-term study sites across the Washington, D.C. region to assess occupancy and habitat use of urban wild turkeys at multiple scales. We found that wild turkey occupancy was positively correlated with the distance to roadways and the proportion of natural vegetation cover within 1 km, whereas occupancy was negatively correlated with the distance to the nearest water source and mean canopy height within 4 km. Our findings add to the understanding of how wild turkeys are returning and using novel urban ecosystems and can inform future management needs, contribute to conservation initiatives, and help reduce negative human–wildlife interactions.

Understanding factors that influence the vulnerability of wild animals to harvest is of interest to wildlife managers as they strive to implement management strategies that achieve population and distribution objectives. Growing evidence suggests that ungulates adjust their behavior to mitigate harvest risk, such as decreasing their rate of movement and selecting habitat indicative of security to lessen detectability. However, few studies have evaluated how behavior that might mitigate harvest risk interacts with age and influences survival. We used 4 years of movement, age, and survival data from 61 adult male elk (Cervus canadensis) in west-central Montana, USA, to test 2 hypotheses: 1) age influences elk behavior amid hunting pressure, and 2) age and behavior interact to influence elk survival during the hunting season. Consistent with our predictions, elk used and selected security attributes, including areas at high elevation and far from motorized routes, but contrary to expectations, elk avoided dense forest on land with public access. Behavior to mitigate risk varied among individual elk and was influenced by age. Young, inexperienced elk (<4 years old) and mature, experienced elk (>7 years old) moved less, used higher elevations, steeper slopes, denser cover, and selected more strongly for land with public access compared with middle-aged elk (4–7 years old). Both age and behavior influenced vulnerability and likelihood of harvest. At the beginning of the hunting season, odds of survival increased by 40% with every 1-year increase in age, but by the end of the hunting season, survival was similar across all age classes. Moreover, male elk were 52% more likely to survive the hunting season when time spent on land with restricted access increased from 0% to 100%. Our findings suggest that elk of varying ages employ flexible strategies to mitigate harvest risk and highlight the behavioral and demographic mechanisms that elicit use of security attributes during a period of heightened risk.

Wind energy development in Africa necessitates understanding its impact on bat populations, particularly bats in the family Pteropodidae, which are ecologically important but understudied in this context. I assessed whether wind turbine-related mortality is likely to cause population-level impacts on Egyptian fruit bat (Rousettus aegyptiacus) and Wahlberg's epauletted fruit bat (Epomophorus wahlbergi) in South Africa, using a Leslie matrix model and potential biological removal (PBR). The matrix model showed population growth for both species, even under low and medium fatality scenarios. Under a high fatality scenario, the probability of population decline reached 60% for Egyptian fruit bat and 72.3% for Wahlberg's epauletted fruit bat, with both species showing a reduction in population size over 100 years. Quasi-extinction risk increased with rising fatality, reaching 21–23% at a 1% annual fatality rate. The PBR results also showed resilience at low to medium fatality levels, but a high fatality scenario could exceed sustainable removal thresholds by 636% for Egyptian fruit bat and 861% for Wahlberg's epauletted fruit bat under precautionary management. The findings indicate that while these fruit bat populations may withstand low to medium levels of turbine-related mortality, increasing fatalities pose a significant risk of long-term population decline. This underscores the need for robust monitoring and a comprehensive understanding of cumulative impacts to align wind energy expansion with biodiversity conservation objectives in Africa. The findings support species-specific, population-based thresholds that reflect demographic sensitivity and spatial exposure. This approach can guide evidence-based regulation and conservation in wind energy planning for African bats.

White-tailed deer (Odocoileus virginianus) populations in the southeastern United States have declined from highs in the 1990s, in part because of lowered recruitment via coyote (Canis latrans) predation on fawns. Reducing coyote density with the goal of increasing fawn survival is not an effective long-term management strategy, with some suggesting that alterations in adult deer harvest and predator management strategies are needed. Accordingly, our objectives were to estimate adult female survival and predict population growth rates under scenarios that differed by adult female harvest, fawn survival, and fawn sex ratio in the Piedmont physiographic region of South Carolina, USA. We found that annual adult female survival was high (0.801), and the deer population was declining by approximately 2% annually. Through simulations, we found that eliminating adult female harvest was most effective at achieving a stable population, and a combination of reduction in adult female harvest and habitat management to increase fawn survival could help achieve a growing deer population. In combination with other recent findings that suggest fawn survival could be increased with less disturbance to maternal care and the availability of alternative foods for coyotes, our results highlight an important path forward for coyote management in the Southeast that moves away from longstanding efforts for localized control or eradication of coyotes to learning to manage deer and coyotes to achieve management goals.

Understanding how adult prey perceive predation risk (i.e., the probability of being killed by a predator) during the rearing of young is particularly important, given juveniles are often most vulnerable to predation. Recent research in the southeastern United States has suggested that maternal behavior is highly correlated with predation of white-tailed deer (Odocoileus virginianus) neonates by coyotes (Canis latrans), offering an important path forward for potential management interventions that improve recruitment in declining deer populations in this region. However, we still lack an understanding of how maternal behaviors (both pre- and post-parturition) relate to predation risk or are mediated by intrinsic factors and extrinsic habitat conditions. We used simultaneous global positioning system (GPS) tracking of adult female deer, neonatal deer, and coyotes, along with a large camera trap array, to assess the response of pre- and post-parturition maternal behaviors to predation risk and habitat conditions in South Carolina, USA, in 2019–2021. We found that pre-parturition, adult female deer selected birth sites near areas of human development, likely to reduce the risk of encountering a coyote. Post-parturition, adult female deer altered the spatial scale of their movement during neonate rearing in response to predation risk. Larger adult female home ranges in areas of high coyote activity support the dispersive maternal care hypothesis, although adult females stayed closer to neonates in areas where coyotes were most likely to forage. However, adult females did not alter finer-scale maternal behaviors (i.e., visitation rates) known to be correlated with fawn survival in our system, suggesting adult female deer either do not perceive areas or times of highest risk at fine spatiotemporal scales, or they do not have the ability to avoid coyotes when performing these critical post-parturition maternal care behaviors. Given the relatively low rate of fawn survival (29%) observed in our system, to help guide future management interventions that enhance optimal maternal behaviors, we encourage researchers to investigate how ungulate maternal behaviors respond to predation risk at multiple spatiotemporal scales in other systems with higher observed neonatal survival.