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Results for “American Wildlife”

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At least 145 records · Page 8Linked to original sources
USGS1937

Sylvatic plague

No abstract available.

California, Idaho, Montana, Nevada, Oregon, Utah, ↗
USGS2017

Evaluation of harvest and information needs for North American sea ducks

Wildlife managers routinely seek to establish sustainable limits of sport harvest or other regulated forms of take while confronted with considerable uncertainty. A growing body of ecological research focuses on methods to describe and account for uncertainty in management decision-making and to prioritize research and monitoring investments to reduce the most influential uncertainties. We used simulation methods incorporating measures of demographic uncertainty to evaluate risk of overharvest and prioritize information needs for North American sea ducks (Tribe Mergini ). Sea ducks are popular game birds in North America, yet they are poorly monitored and their population dynamics are poorly understood relative to other North American waterfowl. There have been few attempts to assess the sustainability of harvest of North American sea ducks, and no formal harvest strategy exists in the U.S. or Canada to guide management. The popularity of sea duck hunting, extended hunting opportunity for some populations (i.e., special seasons and/or bag limits), and population declines have led to concern about potential overharvest. We used Monte Carlo simulation to contrast estimates of allowable harvest and observed harvest and assess risk of overharvest for 7 populations of North American sea ducks: the American subspecies of common eider ( Somateria mollissima dresseri ), eastern and western populations of black scoter ( Melanitta americana ) and surf scoter ( M . perspicillata ), and continental populations of white-winged scoter ( M . fusca ) and long-tailed duck ( Clangula hyemalis ). We combined information from empirical studies and the opinions of experts through formal elicitation to create probability distributions reflecting uncertainty in the individual demographic parameters used in this assessment. Estimates of maximum growth ( r max ), and therefore of allowable harvest, were highly uncertain for all populations. Long-tailed duck and American common eider appeared to be at high risk of overharvest (i.e., observed harvest < allowable harvest in 5–7% and 19–26% of simulations, respectively depending on the functional form of density dependence), whereas the other populations appeared to be at moderate risk to low risk (observed harvest < allowable harvest in 22–68% of simulations, again conditional on the form of density dependence). We also evaluated the sensitivity of the difference between allowable and observed harvest estimates to uncertainty in individual demographic parameters to prioritize information needs. We found that uncertainty in overall fecundity had more influence on comparisons of allowable and observed harvest than adult survival or observed harvest for all species except long-tailed duck. Although adult survival was characterized by less uncertainty than individual components of fecundity, it was identified as a high priority information need given the sensitivity of growth rate and allowable harvest to this parameter. Uncertainty about population size was influential in the comparison of observed and allowable harvest for 5 of the 6 populations where it factored into the assessment. While this assessment highlights a high degree of uncertainty in allowable harvest, it provides a framework for integration of improved data from future research and monitoring. It could also serve as the basis for harvest strategy development as management objectives and regulatory alternatives are specified by the management community.

PLoS ONE↗
USGS2018

Implications of introgression for wildlife translocations: the case of North American martens

The evolutionary consequences of natural introgression provide a rare opportunity to retrospectively evaluate how the introduction of exotics or genetic rescue efforts may impact endemic faunas. Phylogeographic structure among mainland, endemic insular, and introduced North American marten ( Martes americana and M. caurina ) populations have been shaped by a complex history of natural, post-glacial population expansion followed by a series of anthropogenic introductions. In some cases, both natural colonization and translocations facilitated secondary contact, offering a series of replicated experiments that demonstrate how introgression, in these cases following isolation (insular and refugial), shapes genetic diversity. We test whether genetic exchange is occurring between North American marten species using mitochondrial genomes and ten nuclear loci. We present evidence of biased nuclear introgression from M. caurina into M. americana across two natural hybrid zones (insular and mainland) and found no remnant evidence of M. caurina on islands that received M. americana translocations, suggesting prior absence, potential extirpation, or genetic swamping of M. caurina from these islands. Our results highlight the importance of understanding phylogeographic variation prior to identifying source populations for wildlife translocations and caution the use of genetic rescue for North American marten populations. Although previously managed as a single species, these two species show substantial genetic divergence. When the two are placed into contact, they exhibit unidirectional, asymmetric introgression with potentially negative consequences for M. caurina , underscoring the value of mindful consideration of introgression in wildlife management.

Conservation Genetics↗
USGS2017

Cooperative Fish and Wildlife Research Units Program—2016 year in review

Summary The Cooperative Fish and Wildlife Research Units (CRU) Program had a productive year in 2016. Despite vacancies in our scientist ranks exceeding 20 percent, our research, training, and teaching portfolio was full and we graduated 93 students and published 398 manuscripts primarily focused on addressing the real conservation challenges of our cooperators. As I’ve stated before, our mission is our legacy: meeting the actionable science needs of our cooperators, providing them technical guidance and assistance in interpreting and applying new advances in science, and developing the future workforce through graduate education and mentoring. Our scientists and the manner in which they approach our mission continue to inspire me. The most rewarding part of my job is meeting and engaging with the students they recruit—the conservation professionals of the future. I cannot help but feel uplifted after discussions with and presentations by these young men and women. Personally, I owe my place in the profession today to the mentoring I received as a CRU student, and today’s CRU scientists have raised the bar. It gives me hope for the future of conservation, and added motivation to see our vacancies filled so that we can expand our portfolio. The National Cooperators’ Coalition has been active and is strategically working to build support on our behalf. Sincere thanks to the American Fisheries Society, the Association of Fish and Wildlife Agencies, the Boone and Crockett Club, the National Association of University Fish and Wildlife Programs, the Wildlife Management Institute, and The Wildlife Society for their efforts and those of their affiliated members. We co-sponsored a workshop at the 2016 North American Wildlife and Natural Resources Conference along with the American Fisheries Society, the Association of Fish and Wildlife Agencies, the Wildlife Management Institute, and The Wildlife Society, titled “Barriers and Bridges in Reconnecting Natural Resources Science and Management.” The workshop was well received and we have been asked to continue the dialogue with a second workshop in 2017. It was evident during the workshop that the CRU is viewed by our cooperators as an important and essential linkage between academia and practitioners. This is testament to the legacy of the CRU Program and the foundation it is built upon. In this Year in Review report, you will find details on staffing, vacancies, research funding, and other pertinent information. You will also see snapshots of CRU projects with information on how results have been or are being applied by cooperators. That is the essence of what we do: science that matters.

Circular↗
USGS2019

Survival and conflict behavior of American black bears after rehabilitation

Wildlife agencies face difficult situations when orphaned or injured American black bear ( Ursus americanus ) cubs (<12 months old) or yearlings (≥12 and <24 months old) are captured. One option is bear rehabilitation, the care and feeding of cubs or yearlings in a semi‐natural environment, followed by release. Unfortunately, the survival and movements of bears released from rehabilitation facilities are often poorly documented and the ultimate reasons for success or failure poorly understood. Our goal was to assess survival and post‐release conflict of orphaned bear cubs and yearlings following release from a rehabilitation facility, Appalachian Bear Rescue (ABR), in Townsend, Tennessee, USA, from 2015–2016. We predicted that rehabilitated bears would survive at similar rates, die from similar causes, and engage in similar conflict behavior to wild conspecifics. We equipped 42 black bear cubs and yearlings from ABR with global positioning system‐collars and released them in Great Smoky Mountains National Park or Cherokee National Forest, Tennessee and North Carolina, USA. Estimated annual survival using known‐fate methods for all released bears was 0.93 ± 0.06 [SE]). Survival for 13 bears released as cubs was 0.64 ± 0.14, whereas none of the bears released as yearlings died within 1 year after release ( n = 29). Survival of rehabilitated bears was similar to or higher than published rates for wild conspecifics. Three of 42 bears (7.1%) released from ABR engaged in conflict behavior up to 1 year following release, and those had spent time involved in conflict behavior with their mothers (e.g., approaching humans) prior to being orphaned. Despite not having the typical post‐natal experience with their mothers, the bears in our study appeared to behave and survive similarly to their wild conspecifics. Rehabilitation is effective for managing orphaned or injured bears. Best survival occurred for bears released as yearlings; however, managers can maximize cub survival through fall releases when plentiful wild foods are available.

North Carolina, Tennessee↗
USGS2014

Wildlife mortality investigation and disease research: contributions of the USGS National Wildlife Health Center to endangered species management and recovery

The U.S. Geological Survey&mdash;National Wildlife Health Center (NWHC) provides diagnostic services, technical assistance, applied research, and training to federal, state, territorial, and local government agencies and Native American tribes on wildlife diseases and wildlife health issues throughout the United States and its territories, commonwealth, and freely associated states. Since 1975, >16,000 carcasses and specimens from vertebrate species listed under the Endangered Species Act have been submitted to NWHC for determination of causes of morbidity or mortality or assessment of health/disease status. Results from diagnostic investigations, analyses of the diagnostic database, technical assistance and consultation, field investigation of epizootics, and wildlife disease research by NWHC wildlife disease specialists have contributed importantly to the management and recovery of listed species.

EcoHealth↗