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At least 1,045 records · Page 58Linked to original sources
USGS2005

Diseases of tadpoles

This chapter is devoted to the diseases of anuran larvae that cause morbidity( illness) and mortality (death). The purpose of this chapter is to describe diseases that may be encountered in free-living tadpoles of the United States and Canada. Much of the information in this chapter comes from unpublished diagnostic examinations of amphibians done at the U.S. Geological Survey, National Wildlife Health Center (NWHC). Many parasites infect amphibians, and with very few exceptions, these are clinically silent infections (produce no overt evidence of illness or death); accordingly, readers are referred to parasitology texts for a review of protozoan, helminthic and ectoparasitic organisms of amphibians (Flynn, 1973; Poynton and Whitaker, 2001). Diseases presented in this chapter are Ranaviral (iridovirus) infection Adenovirus infection Lucke frog herpesvirus Chytrid fungal infection Watermold infection (saprolegniasis) Coccidiosis Leeches Anchorworms

Book chapter↗
USGS1987

Microbial infections in a declining wild turkey population in Texas

A survey was conducted at 5 locations in Texas for avian pathogens that might adversely affect wild turkey ( Meleagris gallopavo ) productivity and survival. At 1 site, the Rob and Bessie Welder Wildlife Refuge (WWR), turkeys have declined precipitously in recent years. During the winters of 1983-85, 442 wild turkeys were caught with cannon and drop nets, 161 of these on WWR. Blood samples were drawn for serologic evaluation, and cloacal and tracheal swabs were collected for isolation attempts. Salmonella spp. bacteria, Newcastle disease virus (NDV), and avian influenza virus (AIV) were not detected in any samples tested. Serologic tests for antibodies to NDV and AIV also were negative. Many mycoplasma isolates were recovered from turkeys from every location. Characterization of these isolates indicated that several species were present. None were species typically associated with mycoplasmosis in domestic turkeys, such as Mycoplasma gallisepticum (MG), M. meleagridis (MM), or M. synoviae (MS), although antibodies to these pathogens were detected in turkeys at every location sampled. There was no evidence to link any of these disease causing agents to the decline observed in the population of wild turkeys on the WWR.

Texas↗
USGS2021

The scope and severity of white-nose syndrome on hibernating bats in North America

Assessing the scope and severity of threats is necessary for evaluating impacts on populations to inform conservation planning. Quantitative threat assessment often requires monitoring programs that provide reliable data over relevant spatial and temporal scales, yet such programs can be difficult to justify until there is an apparent stressor. Leveraging efforts of wildlife management agencies to record winter counts of hibernating bats, we collated data for 5 species from over 200 sites across 27 U.S. states and 2 Canadian provinces from 1995 to 2018 to determine the impact of white-nose syndrome (WNS), a deadly disease of hibernating bats. We estimated declines of winter counts of bat colonies at sites where the invasive fungus that causes WNS ( Pseudogymnoascus destructans ) had been detected to assess the threat impact of WNS. Three species undergoing species status assessment by the U.S. Fish and Wildlife Service ( Myotis septentrionalis , Myotis lucifugus , and Perimyotis subflavus ) declined by more than 90%, which warrants classifying the severity of the WNS threat as extreme based on criteria used by NatureServe. The scope of the WNS threat as defined by NatureServe criteria was large (36% of Myotis lucifugus range) to pervasive (79% of Myotis septentrionalis range) for these species. Declines for 2 other species ( Myotis sodalis and Eptesicus fuscus ) were less severe but still qualified as moderate to serious based on NatureServe criteria. Data-sharing across jurisdictions provided a comprehensive evaluation of scope and severity of the threat of WNS and indicated regional differences that can inform response efforts at international, national, and state or provincial jurisdictions. We assessed the threat impact of an emerging infectious disease by uniting monitoring efforts across jurisdictional boundaries and demonstrated the importance of coordinated monitoring programs, such as the North American Bat Monitoring Program (NABat), for data-driven conservation assessments and planning.

Conservation Biology↗
USGS2013

Anthropogenic impacts to the recovery of the Mexican gray wolf with a focus on trapping-related incidents

Concerns regarding the potential negative impacts of regulated furbearer trapping to reintroduced Mexican gray wolves (Canis lupus baileyi), led to an executive order prohibiting trapping in the New Mexico, USA, portion of the Blue Range Wolf Recovery Area. This ban was to last for 6 months and required an evaluation of the risk posed to wolves by traps and snares legally permitted in New Mexico. We reviewed potential threats to wolves in the Blue Range Wolf Recovery Area, including threats associated with regulated furbearer trapping. One hundred Mexican gray wolf mortalities have been documented during the reintroduction effort (1998–2011). Of those mortalities with a known cause, >81% were human-caused resulting from illegal shooting (n = 43), vehicle collisions (n = 14), lethal removal by the United States Fish and Wildlife Service (USFWS; n = 12), non-project-related trapping (n = 2), project-related trapping (n = 1), and legal shooting by the public (n = 1). Ten wolves died due to unknown causes. The remaining 17 mortalities were a result of natural causes (e.g., starvation, disease). An additional 23 wolves were permanently, but non-lethally, removed from the wild by the USFWS. Of 13 trapping incidents in New Mexico that involved non-project trappers (i.e., trappers not associated with USFWS or U.S. Department of Agriculture-Wildlife Services), 7 incidents are known to have resulted in injuries to wolves: 2 wolves sustained injuries severe enough to result in leg amputations and 2 additional wolves died as a result of injuries sustained. Foothold traps with rubber-padded jaws and properly set snares may reduce trap-related injuries to Mexican gray wolves; however, impacts caused by trapping are overshadowed by other anthropogenic impacts (e.g., illegal shooting, non-lethal permanent removal, and vehicle collisions).

New Mexico↗
USGS2019

Northern forest winters have lost cold, snowy conditions that are important for ecosystems and human communities

Winter is an understudied but key period for the socio-ecological systems of northeastern North American forests. A growing awareness of the importance of the winter season to forest ecosystems and surrounding communities has inspired several decades of research, both across the northern forest and at other mid- and high-latitude ecosystems around the globe. Despite these efforts, we lack a synthetic understanding of how winter climate change may impact hydrological and biogeochemical processes and the social and economic activities they support. Here we take advantage of 100 years of meteorological observations across the northern forest region of the northeastern U.S. and eastern Canada to develop a suite of indicators that enable a cross-cutting understanding of 1) how winter temperatures and snow cover have been changing and 2) how these shifts may impact both ecosystems and surrounding human communities. We show that cold and snow-covered conditions have generally decreased over the past 100 years. These trends suggest positive outcomes for tree health as related to reduced fine root mortality and nutrient loss associated with winter frost but negative outcomes as related to the northward advancement and proliferation of forest insect pests. In addition to effects on vegetation, reductions in cold temperatures and snow cover are likely to have negative impacts on the ecology of the northern forest through impacts on water, soils, and wildlife. The overall loss of coldness and snow cover may also have negative consequences for logging and forest products, vector-borne diseases and human health, recreation and tourism, and cultural practices, which together represent important social and economic dimensions for the northern forest region. These findings advance our understanding of how our changing winters may transform the socio- ecological system of a region that has been defined by the contrasting rhythm of the seasons. Our research also identifies a trajectory of change that informs our expectations for the future as the climate continues to warm.

Ecological Applications↗
USGS2015

Anticoagulant rodenticides in urban bobcats: exposure, risk factors and potential effects based on a 16-year study

Anticoagulant rodenticides (ARs) are increasingly recognized as a threat to nontarget wildlife. High exposure to ARs has been documented globally in nontarget predatory species and linked to the high prevalence of an ectoparasitic disease, notoedric mange. In southern California, mange associated with AR exposure has been the proximate cause of a bobcat ( Lynx rufus ) population decline. We measured AR exposure in bobcats from two areas in southern California, examining seasonal, demographic and spatial risk factors across landscapes including natural and urbanized areas. The long-term study included bobcats sampled over a 16-year period (1997–2012) and a wide geographic area. We sampled blood ( N = 206) and liver ( N = 172) to examine exposure ante- and post-mortem. We detected high exposure prevalence (89 %, liver; 39 %, blood) and for individuals with paired liver and blood data ( N = 64), 92 % were exposed. Moreover, the animals with the most complete sampling were exposed most frequently to three or more compounds. Toxicant exposure was associated with commercial, residential, and agricultural development. Bobcats of both sexes and age classes were found to be at high risk of exposure, and we documented fetal transfer of multiple ARs. We found a strong association between certain levels of exposure (ppm), and between multiple AR exposure events, and notoedric mange. AR exposure was prevalent throughout both regions sampled and throughout the 16-year time period in the long-term study. ARs pose a substantial threat to bobcats, and likely other mammalian and avian predators, living at the urban-wildland interface.

Ecotoxicology↗
USGS2024

Multistage time-to-event models improve survival inference by partitioning mortality processes of tracked organisms

Advances in tagging technologies are expanding opportunities to estimate survival of fish and wildlife populations. Yet, capture and handling effects could impact survival outcomes and bias inference about natural mortality processes. We developed a multistage time-to-event model that can partition the survival process into sequential phases that reflect the tagged animal experience, including handling and release mortality, post-release recovery mortality, and subsequently, natural mortality. We demonstrate performance of multistage survival models through simulation testing and through fish and bird telemetry case studies. Models are implemented in a Bayesian framework and can accommodate left, right, and interval censorship events. Our results indicate that accurate survival estimates can be achieved with reasonable sample sizes ( n ≈ 100 + ) "> 𝑛≈100+) and that multimodel inference can inform hypotheses about the configuration and length of survival stages needed to adequately describe mortality processes for tracked specimens. While we focus on survival estimation for tagged fish and wildlife populations, multistage time-to-event models could be used to understand other phenomena of interest such as migration, reproduction, or disease events across a range of taxa including plants and insects.

Scientific Reports↗
USGS2004

West Nile Virus and wildlife

West Nile virus (WNV) has spread rapidly across North America, resulting in human deaths and in the deaths of untold numbers of birds, mammals, and reptiles. The virus has reached Central America and the Caribbean and may spread to Hawaii and South America. Although tens of thousands of birds have died, and studies of some bird species show local declines, few regionwide declines can be attributed to WNV. Predicting future impacts of WNV on wildlife, and pinpointing what drives epidemics, will require substantial additional research into host susceptibility, reservoir competency, and linkages between climate, mosquitoes, and disease. Such work will entail a collaborative effort between scientists in governmental research groups, in surveillance and control programs, and in nongovernmental organizations. West Nile virus was not the first, and it will not be the last, exotic disease to be introduced to the New World. Its spread in North America highlights the need to strengthen animal monitoring programs and to integrate them with research on disease ecology.

BioScience↗
USGS2013

Abundance, distribution, and population trends of the iconic Hawaiian Honeycreeper, the ʻIʻiwi (Vestiaria coccinea) throughout the Hawaiian Islands

Naturalists in the 1800s described the ʻIʻiwi (Vestiaria coccinea) as one of the most abundant forest birds, detected in forested areas from sea level to tree line across all the major Hawaiian Islands. However, in the late 1800s, ʻIʻiwi began to disappear from low elevation forests, and by the mid-1900s, the species was largely absent from low- and mid-elevation areas. Today, ʻIʻiwi are restricted to high-elevation forests on the islands of Hawaiʻi, east Maui, and Kauaʻi, with a few birds apparently persisting on Oʻahu, Molokaʻi, and west Maui. ʻIʻiwi are highly vulnerable to introduced disease, and the prevalence of avian malaria in low and mid-elevations is believed to be the cause of ʻIʻiwi being restricted to high elevations where temperatures are too cold for the development of the disease and its mosquito vector. With global warming, it is feared that the disease will move quickly into the high-elevation forests where the last ʻIʻiwi reside, threatening their viability. The U.S. Fish and Wildlife Service was petitioned to list the ʻIʻiwi as an Endangered Species in 2010, and this report provides a comprehensive review of the abundance, distribution, and trends using historical survey data as well as the most recently available survey information (up to 2012). We estimate the total population size of ‘I‘iwi at 550,972–659,864 (mean = 605,418) individuals. Of these, 90 percent are on the island of Hawaiʻi, followed by east Maui (about 10 percent), with less than 1 percent on Kauaʻi. ʻIʻiwi population trends vary across the islands. ʻIʻiwi population in Kauaʻi has experienced sharp declines, with a projected trend of 92 percent decline over a 25 year period based on the 2000–2012 surveys. On East Maui, the northeastern region has experienced declines (34 percent over a 25 year period), while the southeastern region has been stable to moderately increasing. On the island of Hawaiʻi, population trends are mixed. On the windward side, populations are largely declining, although the northern section (Hakalau Forest) has stable populations. On the leeward side, results suggest a strongly increasing population, with estimates of as much as a 147 percent increase over a 25 year period from the Puʻu Waʻawaʻa region. However, it is unclear how much these results from the leeward side of Hawaiʻi show a population trend contrary to population trends in all other areas or are an artifact of a sparsely sampled area. Trends by elevation suggest a large decrease in numbers of ʻIʻiwi at elevations below 1,200 meters on Kauaʻi and northeast Maui. Low elevation ʻIʻiwi populations also appear to have decreased in other regions, although low-elevation areas are not surveyed as often as other areas because of their lack of native forest birds. An exception to this pattern was the lower portions of the Hakalau Forest National Wildlife Refuge Kona Unit in the central leeward part of the island of Hawaiʻi, where populations appeared stable at the lower elevations. Based on the most recent surveys (up to 2012), approximately 50 percent of ʻIʻiwi live in a narrow, 500-meter band at elevations of 1,200–1,700 meters, suggesting that ʻIʻiwi are vulnerable to future shifts in climate.

Hawai'i↗
USGS2011

A national plan for assisting states, federal agencies, and tribes in managing white-nose syndrome in bats

White-nose syndrome (WNS) is a disease responsible for unprecedented mortality in hibernating bats in the northeastern U.S. This previously unrecognized disease has spread very rapidly since its discovery in January 2007, and poses a considerable threat to hibernating bats throughout North America. As WNS spreads, the challenges for understanding and managing the disease continue to increase. Given the escalating complexity of these challenges, a highly coordinated effort is required for State, Federal, and Tribal wildlife agencies, and private partners to respond effectively to WNS and conserve species of bats. The plan proposed herein details the elements that are critical to the investigation and management of WNS, identifies key action items to address stated goals, and outlines the role(s) of agencies and entities involved in this continental effort.

Report↗
USGS2016

Influence of demography and environment on persistence in toad populations

Effective conservation of rare species requires an understanding of how potential threats affect population dynamics. Unfortunately, information about population demographics prior to threats (i.e., baseline data) is lacking for many species. Perturbations, caused by climate change, disease, or other stressors can lead to population declines and heightened conservation concerns. Boreal toads ( Anaxyrus boreas boreas ) have undergone rangewide declines due mostly to the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd), with only a few sizable populations remaining in the southern Rocky Mountains, USA, that are disease-free. Despite the apparent region-wide occurrence of Bd, our focal populations in central Colorado were disease free over a 14-year capture-mark-recapture study until the recent discovery of Bd at one of the sites. We used recapture data and the Pradel reverse-time model to assess the influence of environmental and site-specific conditions on survival and recruitment. We then forecast changes in the toad populations with 2 growth models; one using an average lambda value to initiate the projection, and one using the most recent value to capture potential effects of the incursion of disease into the system. Adult survival was consistently high at the 3 sites, whereas recruitment was more variable and markedly low at 1 site. We found that active season moisture, active season length, and breeding shallows were important factors in estimating recruitment. Population growth models indicated a slight increase at 1 site but decreasing trends at the 2 other sites, possibly influenced by low recruitment. Insight into declining species management can be gained from information on survival and recruitment and how site-specific environmental factors influence these demographic parameters. Our data are particularly useful because they provide baseline data on demographics in populations before a disease outbreak and enhance our ability to detect changes in population parameters potentially caused by the disease.

Journal of Wildlife Management↗
USGS1985

Interpretation of criteria commonly used to determine lead poisoning problem areas

Determination of lead poisoning problem areas is complicated by the nature of the disease process. Rigorous documentation of lead poisoning as a cause of mortality in birds requires the integration and evaluation of pathological and toxicological data by an experienced diagnostician. No single technique provides unequivocal proof that lead exposure occurred at the site of death. However, evaluation processes that integrate knowledge regarding the course of lead poisoning in birds, bird movement patterns in specific geographic areas, and findings from studies involving criteria commonly used to measure exposure to lead shot provide a sound basis for determination of specific problem areas. Sequential sampling during the period of bird use is an important requirement for establishing strong cause and effect relations. Knowledge of lead poisoning characteristics as a disease process are also useful in identifying lead poisoning problem areas.

Fish and Wildlife Leaflet↗
USGS2024

Modeling the response of an endangered rabbit population to RHDV2 and vaccination

Rabbit hemorrhagic disease virus 2 (RHDV2), recently detected in the western United States, has the potential to cause mass mortality events in wild rabbit and hare populations. Currently, few management strategies exist other than vaccination. We developed a spatially explicit model of RHDV2 for a population of riparian brush rabbits ( Sylvilagus bachmani riparius ), a subspecies of brush rabbit classified as endangered in the United States, on a subsection of the San Joaquin River National Wildlife Refuge. The goal of our model was to provide guidance regarding vaccination strategies for an endangered rabbit species. Our model predicts that increased interactions between rabbits (a proxy for landscape connectivity) and disease transmission rates among susceptible hosts (individual brush rabbits and conspecifics) have the greatest influence on the outcome of a potential vaccination campaign. Our model projects that across a range of parameter estimates (given an RHDV2 incursion), the median estimated population size with a 0%–10% vaccination rate after 1 year is 538 rabbits (95% Confidence Interval [C.I.] 69–1235), approximately 36% of the expected size of the study population of 1470 rabbits without an RHDV2 introduction. With a 10%–20%, 20%–30%, or 30%–40% vaccination rate, the median estimated population size increased to 628 rabbits (95% C.I. 130–1298), 723 rabbits (95% C.I. 198–1317), and 774 rabbits (95% C.I. 228–1410), respectively. These estimates represent 43%, 49%, and 53% of the expected population size without an RHDV2 introduction. Overall, a 1% increase in vaccination rate was associated with a six rabbit (95% C.I. 5–7) increase in total remaining population size. This result is dependent on assumptions regarding environmental transmission, home range size (and contact rates of rabbits). Given the relatively short lifespan of rabbits and the potential need for boosters, vaccination programs are most likely to be successful for small target populations where relatively high vaccination rates can be maintained.

California↗
USGS1990

Tuberculosis in wild birds: implications for captive birds

The geographic distribution of avian tuberculosis is widespread but the lack of visible epizootics makes assessment of its impact on wild birds difficult. Generally a low prevalence, widely-scattered, individual animal disease, avian tuberculosis is caused by the same agent in wild and domestic birds. Thus there exists the potential for disease transfer between these two groups in situations that result in direct contact such as wild animals newly captured or transferred from rehabilitation centers, and wild and captive animals intermingling in exhibit areas. During the past 7 yr, tuberculosis caused by Mycobacterium avium, was diagnosed in 64 birds submitted to the National Wildlife Health Research Center from 16 states; avian tuberculosis was the primary diagnosis in 52 of the 64 birds, while the remaining 12 isolates were incidental findings. Twenty-eight of these birds were picked up during epizootics caused by other disease agents including avian cholera, botulism type C, and lead, organophosphorus compound, and cyanide poisoning. Twelve birds were found incidental to birds collected during disease monitoring programs and research projects, and 10 birds were collected by hunters or found sick and euthanatized. Tuberculosis lesions occurred (in order of decreasing frequency) in the liver, intestine, spleen, lung, and air sacs. Several unusual morphological presentations were observed in the gizzard, shoulder joint, jugular vein, face, nares and bill, ureter and bone marrow. Infected birds were collected during all 12 mo of the yr from a variety of species in the Anseriformes, Podicipediformes, Gruiformes, and Falconiformes. Nine of the 46 known age birds were immature indicating that lesions can develop during the first year.

Book↗
USGS2012

A state-based national network for effective wildlife conservation

State wildlife conservation programs provide a strong foundation for biodiversity conservation in the United States, building on state wildlife action plans. However, states may miss the species that are at the most risk at rangewide scales, and threats such as novel diseases and climate change increasingly act at regional and national levels. Regional collaborations among states and their partners have had impressive successes, and several federal programs now incorporate state priorities. However, regional collaborations are uneven across the country, and no national counterpart exists to support efforts at that scale. A national conservation-support program could fill this gap and could work across the conservation community to identify large-scale conservation needs and support efforts to meet them. By providing important information-sharing and capacity-building services, such a program would advance collaborative conservation among the states and their partners, thus increasing both the effectiveness and the efficiency of conservation in the United States.

BioScience↗
USGS2012

Changing climate, changing forests: the impacts of climate change on forests of the northeastern United States and eastern Canada

Decades of study on climatic change and its direct and indirect effects on forest ecosystems provide important insights for forest science, management, and policy. A synthesis of recent research from the northeastern United States and eastern Canada shows that the climate of the region has become warmer and wetter over the past 100 years and that there are more extreme precipitation events. Greater change is projected in the future. The amount of projected future change depends on the emissions scenarios used. Tree species composition of northeast forests has shifted slowly in response to climate for thousands of years. However, current human-accelerated climate change is much more rapid and it is unclear how forests will respond to large changes in suitable habitat. Projections indicate significant declines in suitable habitat for spruce-fir forests and expansion of suitable habitat for oak-dominated forests. Productivity gains that might result from extended growing seasons and carbon dioxide and nitrogen fertilization may be offset by productivity losses associated with the disruption of species assemblages and concurrent stresses associated with potential increases in atmospheric deposition of pollutants, forest fragmentation, and nuisance species. Investigations of links to water and nutrient cycling suggest that changes in evapotranspiration, soil respiration, and mineralization rates could result in significant alterations of key ecosystem processes. Climate change affects the distribution and abundance of many wildlife species in the region through changes in habitat, food availability, thermal tolerances, species interactions such as competition, and susceptibility to parasites and disease. Birds are the most studied northeastern taxa. Twenty-seven of the 38 bird species for which we have adequate long-term records have expanded their ranges predominantly in a northward direction. There is some evidence to suggest that novel species, including pests and pathogens, may be more adept at adjusting to changing climatic conditions, enhancing their competitive ability relative to native species. With the accumulating evidence of climate change and its potential effects, forest stewardship efforts would benefit from integrating climate mitigation and adaptation options in conservation and management plans.

Connecticut;Labrador;Maine;Massachusetts;New Bruns↗