Geology Reports⌕ Search

SEARCH · Geology Reports

Results for “Wildlife Research”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,063 records · Page 59Linked to original sources
USGS2024

Monitoring questing winter tick abundance on traditional moose hunting lands

An important symbolic and subsistence animal for many Native American Tribes, the moose ( Alces alces ; mos in Algonquin, Penobscot language) has been under consistent threat in the northeastern United States because of winter tick ( Dermacentor albipictus ) parasitism over the past several decades, causing declines in moose populations throughout the region. This decline has raised concern for Tribes and agencies that are invested in moose. Given this concern, it is increasingly important to effectively monitor and develop strategies to manage winter ticks to address consistent population declines of moose due to winter ticks. The Penobscot Nation developed a novel strategy to sample questing winter ticks (i.e., ticks that are actively seeking hosts) using a plot-based sampling protocol that may be suitable for heterogeneous habitats. We deployed this protocol in the northeastern United States in 2022 during the tick questing period (Sep–Dec) on Penobscot Nation sovereign trust lands, the White Mountain National Forest and Umbagog National Wildlife Refuge, and western-central Massachusetts, USA. We analyzed the data using occupancy and N-mixture models. Detection probability peaked during mid-October and tick occupancy and abundance were greatest at sites with intermediate understory vegetation height. The sampling protocol was successful at sampling ticks in Massachusetts, where abundances were expected to be low, indicating that it may be useful for studies planning to monitor winter tick distribution and abundance in areas with sub-optimal moose habitat and where winter tick abundance is expected to be low. This approach may also benefit managers or researchers intending to monitor many species of hard ticks, and where imperfect detection is expected.

Maine, Massachusetts, New Hampshire↗
USGS2022

Experimental inoculation trial to determine the effects of temperature and humidity on White-nose Syndrome in hibernating bats

Disease results from interactions among the host, pathogen, and environment. Inoculation trials can quantify interactions among these players and explain aspects of disease ecology to inform management in variable and dynamic natural environments. White-nose Syndrome, a disease caused by the fungal pathogen, Pseudogymnoascus destructans ( Pd ), has caused severe population declines of several bat species in North America. We conducted the first experimental infection trial on the tri-colored bat, Perimyotis subflavus , to test the effect of temperature and humidity on disease severity. We also tested the effects of temperature and humidity on fungal growth and persistence on substrates. Unexpectedly, only 37% (35/95) of bats experimentally inoculated with Pd at the start of the experiment showed any infection response or disease symptoms after 83 days of captive hibernation. There was no evidence that temperature or humidity influenced infection response. Temperature had a strong effect on fungal growth on media plates, but the influence of humidity was more variable and uncertain. Designing laboratory studies to maximize research outcomes would be beneficial given the high costs of such efforts and potential for unexpected outcomes. Understanding the influence of microclimates on host–pathogen interactions remains an important consideration for managing wildlife diseases, particularly in variable environments.

Scientific Reports↗
USGS2007

Ecological Investigations of the Federally Endangered Shivwits Milk-Vetch (Astragalus ampullarioides)--2006 Annual Report

Astragalus ampullarioides (Welsh) Welsh, the Shivwits milk-vetch, is an herbaceous perennial legume that was listed as federally endangered in September 2001. Known populations of this edaphic endemic species are restricted to Washington County, Utah, with the majority of occurrences found on gently sloping outcrops of the Triassic Petrified Forest Member of the Chinle Formation at the edge of the Mojave Desert. At the time of listing in 2001, surveys estimated a total of 1000 individuals for the species. In April-May 2006, surveys estimated approximately 4205 individuals distributed among six populations. Of the total number of individuals estimated in spring 2006, over 75 percent were distributed among three subpopulations in Zion National Park and approximately 60 percent occurred at a single 0.3-ha site in the Park. In addition to small population sizes and limited geographic distributions, the species is threatened to varying degrees by urbanization, livestock grazing, off-road vehicle use, and invasive exotic plants. In April 2006, the U.S. Geological Survey (USGS) initiated ecological investigations of the Shivwits milk-vetch to support conservation management and recovery of the species by the National Park Service (NPS; Zion National Park), the U.S. Fish and Wildlife Service (USFWS), the Bureau of Land Management (BLM), the Shivwits Band of the Paiute Tribe, and other cooperators such as The Nature Conservancy of Utah (TNC). To date, funding for this research has been provided by the Southwest Biological Science Center of the USGS Biological Resources Discipline, the USGS-NPS Park-Oriented Biological Support Project, and the Earth Surface Dynamics Program of the USGS Geologic Discipline. Additional logistical support has been provided by the Bureau of Land Management, Grand Staircase-Escalante National Monument. General objectives of this research are (1) to develop a better understanding of species-environment relations to support habitat modelling, future surveys for additional recovery populations, and potential efforts to establish new recovery populations; and (2) to evaluate effects of invasive exotic plants on habitat conditions and measures of milk-vetch performance. Specific objectives are to: Describe the distribution and abundance of milk-vetch populations and associated invasive exotic plant species within and outside of Zion National Park (Zion NP) in relation to geologic / geomorphic setting, soil properties, and plant community composition. In a field setting in Zion NP, conduct experiments to evaluate effects of invasive exotic plants on reproductive output and seedling establishment of A. ampullarioides across a gradient of exotic species biomass. Conduct greenhouse studies and analyze soils to evaluate effects of invasive exotic plants on soil biological properties (including mycorrhizal inocculation potential) that affect cycling and plant uptake of essential mineral nutrients. Based on environmental characteristics of known population locations, use Geographic Information System (GIS) tools to prepare a predictive habitat model that can be used to guide future surveys and efforts to evaluate sites for reintroduction efforts. This report describes 2006 progress and future plans for achieving these four objectives.

Open-File Report↗
USGS2012

Preliminary investigations of the winter ecology of Long-billed Curlews in coastal Texas

Since the early 1900s, the distribution of the Long-billed Curlew ( Numenius americanus ) has contracted dramatically in the eastern one-half of its historic range. The species has been designated as a "Bird of Conservation Concern" and focal species by the U.S. Fish and Wildlife Service, a species of concern by several states, and a "Highly Imperiled" species in the U.S. Shorebird Conservation Plan. The uncertain outlook for this species has contributed to a plethora of research on Long-billed Curlews, most of which have focused on breeding and nesting ecology of the species. Gaps remain in information about factors affecting population dynamics on the winter grounds and the linkages between Long-billed Curlew populations on the breeding range, migration routes, and winter range. To begin filling those gaps, a pilot study was done to evaluate (1) curlew use of nocturnal roost sites, (2) use of public outreach to locate curlews and contribute to preliminary assessment of foraging habitat use, (3) six different methods to capture curlews, and (4) movements by curlews on wintering areas. The study area includes the lower Texas coast, which harbors the eastern-most dense populations of Long-billed Curlews in North America. Use of historical winter roost sites was not observed; however, there was documented limited use (up to 150 curlews) of several new roost sites, some of which were used on an intermittent or erratic basis. Reports elicited from the public indicated Long-billed Curlews wintering in coastal Texas often forage in open, grass-covered lots of partially developed residential areas, golf courses, and public parks within urban and suburban zones. Curlews were reported to use these sites in developed areas as far as 100 kilometers inland. Other reports indicated Long-billed Curlews foraging in farm fields, shallow coastal marsh, and on the beaches of Gulf of Mexico barrier islands. The effectiveness of six techniques for capture of Long-billed Curlews was evaluated in the study. Seven curlews were captured and banded with four of six methods attempted. At least one curlew each was captured with (1) noose ropes, (2) baited bow net, (3) Coda Netgun, and (4) whoosh net; no curlews were caught with a cast net or Super Talon netgun. The Coda Netgun proved to be the most effective methodology examined. Captured birds (7) were weighed, measured, and banded. Body masses (mean = 518 grams) were low compared to data previously published on body mass of Long-billed Curlews. There were 22 observations recorded of banded curlews. Resightings confirmed that birds were not harmed during capture. All of the 22 resightings occurred within two kilometers of the banding locations, suggesting that birds remained near their chosen foraging areas. Results from this 1-year pilot study yielded an intriguing combination of findings that warrant further investigation. Observations include reduced numbers of roosting birds along the Texas coast during dry conditions, highly dynamic use of nocturnal roost sites, use of widely divergent habitat types for foraging, low body mass of most captured birds, and apparent fidelity to general feeding areas. Future investigations of this eastern winter population of curlews would benefit from larger sample sizes and monitoring of individual birds.

Texas↗
USGS2018

Chronic wasting disease—Status, science, and management support by the U.S. Geological Survey

The U.S. Geological Survey (USGS) investigates chronic wasting disease (CWD) at multiple science centers and cooperative research units across the Nation and supports the management of CWD through science-based strategies. CWD research conducted by USGS scientists has three strategies: (1) to understand the biology, ecology, and causes and distribution of CWD; (2) to assess and predict the spread and persistence of CWD in wildlife and the environment; and (3) to develop tools for early detection, diagnosis, surveillance, and control of CWD.

Open-File Report↗
USGS2019

Climate adaptation Science Centers—Annual report for 2018

2018 marked the 10-year anniversary of the establishment of the U.S. Geological Survey (USGS) National Climate Change and Wildlife Science Center! With the passage of the fiscal year 2018 budget on March 23, 2018, our program name was changed from the National Climate Change and Wildlife Science Center to the National Climate Adaptation Science Center (NCASC). The eight regional Department of the Interior (DOI) Climate Science Centers were renamed Climate Adaptation Science Centers (CASCs). The name changes more clearly align the national and regional centers and emphasize their focus on meeting natural resource adaptation needs. Although the program has a new name, our mission has not changed. We are still hard at work delivering science to help fish, wildlife, water, land, and people adapt to a changing climate. During the past 10 years, the NCASC and the eight regional CASCs funded over 425 science projects and built a network of research partners, resource management stakeholders, interdisciplinary staff, fellows, and early career researchers. In celebration of our work and accomplishments over the last 10 years, the NCASC began a monthly web post series on “10 Things You May Not Know” about topics our science has focused on, including drought, glaciers, and wildfire. Additionally, CASCs that had completed their initial hosting agreement with the USGS underwent a formal review and recompetition process. New hosting agreements were awarded to the Southwest and North Central CASCs in 2018. Read the 2018 annual report to learn more about the CASCs' great science, partnerships, capacity building, and more from 2018.

Open-File Report↗
USGS2009

Impact of wildfire on levels of mercury in forested watershed systems: Voyageurs National Park, Minnesota

Atmospheric deposition of mercury to remote lakes in mid-continental and eastern North America has increased approximately threefold since the mid-1800s (Swain and others, 1992; Fitzgerald and others, 1998; Engstrom and others, 2007). As a result, concerns for human and wildlife health related to mercury contamination have become widespread. Despite an apparent recent decline in atmospheric deposition of mercury in many areas of the Upper Midwest (Engstrom and Swain, 1997; Engstrom and others, 2007), lakes in which fish contain levels of mercury deemed unacceptable for human consumption and possibly unacceptable for fish-consuming wildlife are being detected with increasing frequency. In northern Minnesota, Voyageurs National Park (VNP) (fig. 1) protects a series of southern boreal lakes and wetlands situated on bedrock of the Precambrian Canadian Shield. Mercury contamination has become a significant resource issue within VNP as high concentrations of mercury in loons, bald eagle eaglets, grebes, northern pike, and other species of wildlife and fish have been found. The two most mercury-contaminated lakes in Minnesota, measured as methylmercury in northern pike ( Esox lucius ), are in VNP. Recent multidisciplinary U.S. Geological Survey (USGS) research demonstrated that the bulk of the mercury in lake waters, soils, and fish in VNP results from atmospheric deposition (Wiener and others, 2006). The study by Wiener and others (2006) showed that the spatial distribution of mercury in watershed soils, lake waters, and age-1 yellow perch ( Perca flavescens ) within the Park was highly variable. The majority of factors correlated for this earlier study suggested that mercury concentrations in lake waters and age-1 yellow perch reflected the influence of ecosystem processes that affected within-lake microbial production and abundance of methylmercury (Wiener and others, 2006), while the distribution of mercury in watershed soils seemed to be partially dependent on forest disturbance, especially the historic forest fire pattern (Woodruff and Cannon, 2002). Forest fire has an essential role in the forest ecosystems of VNP (Heinselman, 1996). Because resource and land managers need to integrate both natural wildfire and prescribed fire in management plans, the potential influence of fire on an element as sensitive to the environment as mercury becomes a critical part of their decisionmaking. A number of recent studies have shown that while fire does have a significant impact on mercury at the landscape level, the observed effects of fire on aquatic environments are highly variable and unpredictable (Caldwell and others, 2000; Garcia and Carrigan, 2000; Kelly and others, 2006; Nelson and others, 2007). Caldwell and others (2000) described an increase in methylmercury in reservoir sediments resulting from mobilization and transport of charred vegetative matter following a fire in New Mexico. Krabbenhoft and Fink (2000) attributed increases in total mercury concentrations in young-of-the-year fish in the Florida Everglades to release of mercury resulting from peat oxidation following fires. A fivefold increase in whole-body mercury accumulation by rainbow trout ( Oncorhynchus mykiss ) following a fire in Alberta, Canada, apparently resulted from increased nutrient concentrations that enhanced productivity and restructured the food web of a lake within the fire’s burn footprint (Kelly and others, 2006). For this study, we determined the short-term effects of forest fire on mercury concentrations in terrestrial and aquatic environments in VNP by comparing and contrasting mercury concentrations in forest soils, lake waters, and age-1 yellow perch for a burned watershed and an adjacent lake, with similar samples from watersheds and lakes with no fire activity (control watersheds and lakes). The concentration of total mercury in whole, 1-year-old yellow perch serves as a good biological indicator for monitoring trends in methylmercury concentrations in food webs of lakes in North America (Wiener and others, 2007). With a limited gape, age-1 yellow perch that hatched the previous year and resided in a lake for 1 year feed largely on zooplankton and small benthic invertebrates. Thus, age-1 yellow perch provide a baseline for methylmercury concentrations for individual lakes that can be compared across spatial areas. The nine appendixes that accompany this report contain the complete datasets for soils, lake waters, and age-1 yellow perch collected for this study. This report uses data from these three media to provide a framework for evaluating short-term effects of fire on mercury in forested soils and possible effects of the mobilization of mercury from soils on lake water quality and aquatic health.

Minnesota↗
USGS1989

The Animal Welfare Act and the zoo: A positive approach

Interpretations of the Animal Welfare Act and other regulations governing use of research animals in the United States are changing. Recent amendments to the Act have resulted in the inclusion of more species under the umbrella of regulation. The role of the zoo and wildlife veterinarian should be that of leading his or her institution into a positive endorsement of these regulations and their application. Recent additions to the Code of Federal Regulations spell out the roles of the veterinarian and the Animal Care and Use Committee at an institution.

Journal of Zoo and Wildlife Medicine↗
USGS2002

Basis and methods of NASA airborne topographic mapper lidar surveys for coastal studies

This paper provides an overview of the basic principles of airborne laser altimetry for surveys of coastal topography, and describes the methods used in the acquisition and processing of NASA Airborne Topographic Mapper (ATM) surveys that cover much of the conterminous US coastline. This form of remote sensing, also known as "topographic lidar", has undergone extremely rapid development during the last two decades, and has the potential to contribute within a wide range of coastal scientific investigations. Various airborne laser surveying (ALS) applications that are relevant to coastal studies are being pursued by researchers in a range of Earth science disciplines. Examples include the mapping of "bald earth" land surfaces below even moderately dense vegetation in studies of geologic framework and hydrology, and determination of the vegetation canopy structure, a key variable in mapping wildlife habitats. ALS has also proven to be an excellent method for the regional mapping of geomorphic change along barrier island beaches and other sandy coasts due to storms or long-term sedimentary processes. Coastal scientists are adopting ALS as a basic method in the study of an array of additional coastal topics. ALS can provide useful information in the analysis of shoreline change, the prediction and assessment of landslides along seacliffs and headlands, examination of subsidence causing coastal land loss, and in predicting storm surge and tsunami inundation.

Journal of Coastal Research↗
USGS2016

Effects of drought and fire on bird communities of the Kofa National Wildlife Refuge, Arizona

Executive Summary The U.S. Government created the Kofa National Wildlife Refuge (Kofa NWR) in 1939 in response to a citizen campaign to improve desert bighorn sheep populations in Arizona. The Kofa NWR is mountainous and remote, and its management by the U.S. Fish and Wildlife Service (FWS) keeps anthropogenic disturbance levels low. As such, Partners In Flight (PIF) listed the Kofa NWR as one of its Sonoran Desert portfolio sites in its Desert Bird Conservation Plan (McCreedy and others, 2009). Research presented here demonstrates that bird communities within a well-managed and remote Sonoran Desert portfolio site can nonetheless be negatively affected by human-caused stressors like fire and Brown-headed Cowbird ( Molothrus ater ) parasitism, which originate from beyond the Kofa NWR’s boundaries. In chapter 1, we examine how avian productivity can be influenced by timing of nest initiation. We demonstrate that (1) late nesting dates are correlated with low winter precipitation levels, a condition expected to occur in greater frequency in coming decades due to climate change (Seager and others, 2007) and that (2) late nesting dates result in decreased productivity, due to higher rates of nest depredation and, in the case of an open-cup nesting species, higher rates of brood parasitism experienced later in the breeding season. The brood parasite, the Brown-headed Cowbird, appears to forage and roost on agricultural lands north of the Kofa NWR’s boundary. From that location, they commute to the refuge to parasitize other passerine bird nests. Drought and subsequent loss in primary production have been correlated with decreased productivity for birds that breed in arid habitats (Preston and Rotenberry, 2006; Chase and others, 2005; Johnson and others, 2002; Morrison and Bolger, 2002; Brown and Li, 1996; Anderson and Anderson, 1973), yet drought’s standing as a threat to bird populations has been underestimated in recent regional conservation planning efforts (McCreedy and others, 2009; Latta and others, 1999). In chapter 2, we examine the effects of the King Valley fire on breeding and migrant birds within the Kofa NWR. This fire was caused by incendiary weapons testing within Yuma Proving Ground, south of the Kofa NWRboundary (Esque and others, 2013). We found large differences in spring migrant and breeding species abundance and richness between bird count stations within the 2005 King Valley fire zone and bird count stations immediately outside the fire perimeter. Habitat loss to fire, and the subsequent slow regeneration of a Sonoran Desert flora that is not well adapted to fire disturbance, is a recognized threat to bird populations (McCreedy and others, 2009; Latta, 1999), and of all Sonoran Desert wildlife, birds may be the most impacted by loss of perennial Sonoran Desert vegetation to fire (Esque and Schwalbe, 2002). We conclude that decreases in both breeding and migrant use of washes within burned areas will likely persist into the long term (>25 years) due to slow return rates of xeroriparian woodlands lost in the fire.

Arizona↗
USGS2002

Predators

Calving caribou ( Rangifer tarandus ) of the Central Arctic herd, Alaska, have avoided the infrastructure associated with the complex of petroleum development areas from Prudhoe Bay to Kuparuk (Cameron et al. 1992, Nellemann and Cameron 1998, and Section 4 of this document). Calving females of the Porcupine caribou herd may similarly avoid any oil field roads and pipelines developed in areas traditionally used during the calving and post-calving periods. This may displace the caribou females and calves to areas east and south of the 1002 Area of the Arctic National Wildlife Refuge. Increased calf mortality could occur if calving caribou are displaced into areas that have a higher density of predators, higher rates of predation, or where a higher proportion of the predators regularly use caribou as a food source (Whitten et al. 1992). Our study assessed predation risks to caribou calving in the 1002 Area versus calving in potential displacement areas. Due to funding constraints, our research focused on grizzly bears ( Ursus arctos ), with wolves (Camus lupus) and golden eagles ( Aquila chrysaetos ) receiving only cursory attention. Our research objectives were 1) to compare relative abundance of predators within the 1002 Area with that in adjacent peripheral areas, 2) to determine factors affecting predator abundance on the calving grounds, and 3) to quantify the use of caribou as a food source for predators and the importance of caribou to the productivity of predator populations using the coastal plain of the Arctic National Wildlife Refuge.

Alaska, Northwest Territories, Yukon Territory↗
USGS2008

Impacts of Low-Flow and Stream-Temperature Changes on Endangered Atlantic Salmon - Current Research

Recent climate studies in New England and the northeastern United States have shown evidence of physical changes over time, including trends toward earlier snowmelt runoff, decreasing river ice, and increasing spring water temperatures. A U.S. Geological Survey (USGS) study funded by the National Global Warming and Wildlife Science Center will be investigating changes in summer low streamflows and stream temperatures and the potential effects of those changes on endangered Atlantic salmon populations. The study also will evaluate management options that would be most likely to mitigate the effects of any changes in streamflow and temperature.

Fact Sheet↗
USGS2019

Noninvasive identification of cryptic herpetofauna from fecal samples: A novel approach pairing conservation dog surveys and genetic analysis

Noninvasive fecal sampling combined with genetic analysis is a powerful technique allowing the study of elusive or otherwise difficult to monitor species without the need for direct contact. While this method is widely used in birds and mammals, it has never been successfully applied on a large scale in reptiles. The blunt-nosed leopard lizard (Gambelia sila) is an endangered species endemic to the San Joaquin Desert of California. Presently, acquiring data on G. sila for research and management involves more traditional methods such as live capture to obtain tissue samples for DNA analysis, or observation via visual surveys, which are also used for regulatory monitoring in accordance with wildlife agency protocols. Here we describe an innovative approach for gathering additional information, that combines use of conservation detection dogs trained to locate G. sila scat samples with genetic analysis for identifying and distinguishing among sympatric lizard species. We developed two PCR assays that produce fluorescently labelled amplicons of species-specific fragment length for six lizard species in the study area. Using these assays we genetically identifed to species 78% (255 of 327) of samples collected by dog-handler teams across four years. The majority of the genetically identifed samples (82.4%; 210 of 255) were confirmed as originating from G. sila. Beyond the immediate application of these techniques for the study and monitoring of G. sila, our ability to recover usable DNA and to differentiate among a diverse group of lizards highlights the broad potential of our methodology for noninvasive sampling in reptiles.

California↗
USGS2025

Placing environmental DNA monitoring for new detections into perspective: Fishes in the Milwaukee River, Wisconsin

Invasive species management frameworks, such as the early detection of and rapid response to invasive species, use monitoring programs to detect new species occurrences. Resource managers use environmental DNA (eDNA) as one tool for these monitoring programs. An eDNA detection in a new location may lack perspective for resource managers and researchers because of the rarity of potential invaders and the randomness in their dispersal and detection. An example monitoring program is the eDNA-based sampling approach used by the U.S. Fish and Wildlife Service for bigheaded carps Hypophthalmichthys spp. in the upper Mississippi River and Great Lakes Basins that collects hundreds of water samples per event. The U.S. Fish and Wildlife Service detected a single positive sample for Bighead Carp Hypophthalmichthys nobilis during the spring 2021 sampling event in the Kinnickinnic River within the Milwaukee River Basin, and detected a second single positive sample for bigheaded carps during the fall 2021 sampling event in the Milwaukee River. The U.S. Fish and Wildlife Service did not detect any bigheaded carps in previous years (2015 to 2020) or in either the spring or fall 2022 sampling events. These detections lacked perspective, such as detection numbers for other species. We reanalyzed the 2021 and 2022 samples for four existing species of fish: two fairly common species (Common Carp Cyprinus carpio and Gizzard Shad Dorosoma cepedianum ) and two fairly rare species (Burbot Lota lota and Grass Carp Ctenopharyngodon idella ). We detected Common Carp during all four sampling events, Gizzard Shad during three of four sampling events, and Burbot and Grass Carp during two of four sampling events. These results demonstrated that current sampling efforts could detect other species, and bigheaded carp eDNA was not common in the Milwaukee River compared to these species. More specifically, this finding indicates bigheaded carp eDNA detections are as rare as, or rarer than, Grass Carp eDNA detections, a recent invader to the basin. Our findings also demonstrated how reanalyzing eDNA samples after positive detections for targeted species can help managers understand the context of the detections and provide perspective for the relative abundance of the targeted species. Additionally, our results highlight the importance of completing long-term eDNA-based monitoring rather than a single sampling or inventory event. These detections may have been missed in a single year or sampling event, whereas a multiyear monitoring program provides an opportunity to observe trends through time.

Wisconsin↗
USGS2014

A test of the compensatory mortality hypothesis in mountain lions: a management experiment in West-Central Montana

Mountain lions ( Puma concolor ) are widely hunted for recreation, population control, and to reduce conflict with humans, but much is still unknown regarding the effects of harvest on mountain lion population dynamics. Whether human hunting mortality on mountain lions is additive or compensatory is debated. Our primary objective was to investigate population effects of harvest on mountain lions. We addressed this objective with a management experiment of 3 years of intensive harvest followed by a 6-year recovery period. In December 2000, after 3 years of hunting, approximately 66% of a single game management unit within the Blackfoot River watershed in Montana was closed to lion hunting, effectively creating a refuge representing approximately 12% (915 km 2 ) of the total study area (7,908 km 2 ). Hunting continued in the remainder of the study area, but harvest levels declined from approximately 9/1,000 km 2 in 2001 to 2/1,000 km 2 in 2006 as a result of the protected area and reduced quotas outside. We radiocollared 117 mountain lions from 1998 to 2006. We recorded known fates for 63 animals, and right-censored the remainder. Although hunting directly reduced survival, parameters such as litter size, birth interval, maternity, age at dispersal, and age of first reproduction were not significantly affected. Sensitivity analysis showed that female survival and maternity were most influential on population growth. Life-stage simulation analysis (LSA) demonstrated the effect of hunting on the population dynamics of mountain lions. In our non-hunted population, reproduction (kitten survival and maternity) accounted for approximately 62% of the variation in growth rate, whereas adult female survival accounted for 30%. Hunting reversed this, increasing the reliance of population growth on adult female survival (45% of the variation in population growth), and away from reproduction (12%). Our research showed that harvest at the levels implemented in this study did not affect population productivity (i.e., maternity), but had an additive effect on mountain lion mortality, and therefore population growth. Through harvest, wildlife managers have the ability to control mountain lion populations.

Montana↗
USGS1995

Gonadal steroidogenesis in-vitro from juvenile alligators obtained from contaminated or control lakes

The ubiquitous distribution of many contaminants and the nonlethal, multigenerational effects of such contaminants on reproductive, endocrine, and immune systems have led to concerns that wildlife worldwide are affected. Although the causal agents and effects are known for some species, the underlying physiological mechanisms associated with contaminant-induced reproductive modifications are still poorly understood and require extensive research. We describe a study examining the steroidogenic activity of gonads removed from juvenile alligators (Alligator mississippiensis) obtained from contaminated or control lakes in central Florida. Synthesis of estradiol-17 beta (E2) was significantly different when ovaries from the contaminated and control lakes were compared in vitro. Additionally, testes from males obtained from the contaminated lake. Lake Apopka, synthesized significantly higher concentrations of E2 when compared to testes obtained from control males. In contrast, testosterone (T) synthesis from all testes examined in this study displayed a normal pattern and produced concentrations greater than that observed from ovaries obtained from either lake. Interestingly, the pattern of gonadal steroidogenesis differs from previously reported plasma concentrations of these hormones obtained from the same individuals. We suggest that the differences between the in vivo and in vitro patterns are due to modifications in the hepatic degradation of plasma sex steroid hormones.

Environmental Health Perspectives↗
USGS1965

Results of woodcock wing collections, 1959 to 1962

During hunting seasons from 1959 to 1962, age and sex determined from 45,444 wings were used to measure annual productivity of woodcocks ( Philohela minor ). Age of birds was determined by pattern and color of secondaries and by wear on primaries. Sex was determined by width and length of primaries. Overall age ratios, weighted by kill estimates, were the same each year and indicated no change in annual productivity. Immature sex ratios in the combined kill were nearly even each year, but kill of adult females was much larger than kill of adult males. The difference in sex ratios between immatures and adults thus suggests higher mortality of males than females after the first hunting season. Since woodcocks are promiscuous, an unbalanced adult sex ratio in favor of females probably does not reduce productivity. There are, however, factors affecting reliability of information deduced from wing collections, and further research is necessary to answer questions on differential vulnerability and mortality rates.

Connecticut, Louisiana, Maine, Massachusetts, Mich↗
USGS2011

A bibliography of literature pertaining to plague ( Yersinia pestis )

Plague is an acute and often fatal zoonotic disease caused by the bacterium Yersinia pestis . Y. pestis mainly cycles between small mammals and their fleas; however, it has the potential to infect humans and frequently causes fatalities if left untreated. It is often considered a disease of the past; however, since the late 1800s, plagueis geographic range has expanded greatly, posing new threats in previously unaffected regions of the world, including the Western United States. A literature search was conducted using Internet resources and databases. The keywords chosen for the searches included plague, Yersinia pestis , management, control, wildlife, prairie dogs, fleas, North America, and mammals. Keywords were used alone or in combination with the other terms. Although this search pertains mostly to North America, citations were included from the international research community, as well. Databases and search engines used included Google ( http://www.google.com ), Google Scholar ( http://scholar.google.com ), SciVerse Scopus ( http://www.scopus.com ), ISI Web of Knowledge ( http://apps.isiknowledge.com ), and the USGS Library's Digital Desktop ( http://library.usgs.gov ). The literature-cited sections of manuscripts obtained from keyword searches were cross-referenced to identify additional citations or gray literature that was missed by the Internet search engines. This Open-File Report, published as an Internet-accessible bibliography, is intended to be periodically updated with new citations or older references that may have been missed during this compilation. Hence, the authors would be grateful to receive notice of any new or old papers that the audience (users) think need to be included.

Open-File Report↗