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USGS2011

Evidence and implications of recent and projected climate change in Alaska's forest ecosystems

The structure and function of Alaska's forests have changed significantly in response to a changing climate, including alterations in species composition and climate feedbacks (e.g., carbon, radiation budgets) that have important regional societal consequences and human feedbacks to forest ecosystems. In this paper we present the first comprehensive synthesis of climate-change impacts on all forested ecosystems of Alaska, highlighting changes in the most critical biophysical factors of each region. We developed a conceptual framework describing climate drivers, biophysical factors and types of change to illustrate how the biophysical and social subsystems of Alaskan forests interact and respond directly and indirectly to a changing climate. We then identify the regional and global implications to the climate system and associated socio-economic impacts, as presented in the current literature. Projections of temperature and precipitation suggest wildfire will continue to be the dominant biophysical factor in the Interior-boreal forest, leading to shifts from conifer- to deciduous-dominated forests. Based on existing research, projected increases in temperature in the Southcentral- and Kenai-boreal forests will likely increase the frequency and severity of insect outbreaks and associated wildfires, and increase the probability of establishment by invasive plant species. In the Coastal-temperate forest region snow and ice is regarded as the dominant biophysical factor. With continued warming, hydrologic changes related to more rapidly melting glaciers and rising elevation of the winter snowline will alter discharge in many rivers, which will have important consequences for terrestrial and marine ecosystem productivity. These climate-related changes will affect plant species distribution and wildlife habitat, which have regional societal consequences, and trace-gas emissions and radiation budgets, which are globally important. Our conceptual framework facilitates assessment of current and future consequences of a changing climate, emphasizes regional differences in biophysical factors, and points to linkages that may exist but that currently lack supporting research. The framework also serves as a visual tool for resource managers and policy makers to develop regional and global management strategies and to inform policies related to climate mitigation and adaptation.

Alaska↗

USGS2021

Consequences of migratory coupling of predators and prey when mediated by human actions

Aim Animal migrations influence ecosystem structure, dynamics and persistence of predator and prey populations. The theory of migratory coupling postulates that aggregations of migrant prey can induce large-scale synchronized movements in predators, and this coupling is consequential for the dynamics of ecological communities. The degree to which humans influence these interactions remains largely unknown. We tested whether creation of large resource pulses by humans such as seasonal herding of reindeer Rangifer tarandus and hunting of moose, Alces alces , can induce migratory coupling with Golden Eagles, Aquila chrysaetos, and whether these lead to demographic consequences for the eagles. Location Fennoscandia. Methods We used movement data from 32 tracked Golden Eagles spanning 125 annual migratory cycles over 8 years. We obtained reindeer distribution data through collaboration with reindeer herders based on satellite tracking of reindeer, and moose harvest data from the national hunting statistics for Sweden. We assessed demographic consequences for eagles from ingesting lead from ammunition fragments in moose carcasses through survival estimates and their links with lead concentrations in eagles' blood. Results In spring, eagles migrated hundreds of kilometres to be spatially and temporally coupled with calving reindeer, whereas in autumn, eagles matched their distribution with the location and timing of moose hunt. Juveniles were more likely to couple with reindeer calving, whereas adults were particularly drawn to areas of higher moose harvest. Due to this coupling, eagles ingested lead from spent ammunition in moose offal and carcasses and the resulting lead toxicity increased the risk of mortality by 3.4 times. Main conclusions We show how migratory coupling connects landscape processes and that human actions can influence migratory coupling over large spatial scales and increase demographic risks for predators. We provide vital knowledge towards resolving human–wildlife conflicts and the conservation of protected species over a large spatial and temporal scale.

Diversity and Distributions↗

USGS1999

Potential energetic effects of mountain climbers on foraging grizzly bears

Most studies of the effects of human disturbance on grizzly bears (Ursus arctos horribilis) have not quantified the energetic effects of such interactions. In this study, we characterized activity budgets of adult grizzly bears as they foraged on aggregations of adult army cutworm moths (Euxoa auxiliaris) in the alpine of Glacier National Park, Montana, during 1992, 1994, and 1995. We compared the activity budgets of climber-disturbed bears to those of undisturbed bears to estimate the energetic impact of climber disturbance. When bears detected climbers, they subsequently spent 53% less time foraging on moths, 52% more time moving within the foraging area, and 23% more time behaving aggressively, compared to when they were not disturbed. We estimated that grizzly bears could consume approximately 40,000 moths/day or 1,700 moths/hour. At 0.44 kcal/moth, disruption of moth feeding cost bears approximately 12 kcal/minute in addition to the energy expended in evasive maneuvers and defensive behaviors. To reduce both climber interruption of bear foraging and the potential for aggressive bear-human encounters, we recommend routing climbers around moth sites used by bears or limiting access to these sites during bear-use periods.

Wildlife Society Bulletin↗

USGS2015

Pathogen exposure varies widely among sympatric populations of wild and domestic felids across the United States

Understanding how landscape, host, and pathogen traits contribute to disease exposure requires systematic evaluations of pathogens within and among host species and geographic regions. The relative importance of these attributes is critical for management of wildlife and mitigating domestic animal and human disease, particularly given rapid ecological changes, such as urbanization. We screened >1,000 samples from sympatric populations of puma (Puma concolor), bobcat (Lynx rufus) and domestic cat (Felis catus) across urban gradients in six sites, representing three regions, in North America for exposure to a representative suite of bacterial, protozoal and viral pathogens (Bartonella sp., Toxoplasma gondii, feline herpesvirus-1, feline panleukopenea virus, feline calicivirus, feline immunodeficiency virus). We evaluated prevalence within each species, and examined host trait and land cover determinants of exposure-providing an unprecedented analysis of factors relating to potential for infections in domesticated and wild felids. Prevalence differed among host species (highest for puma and lowest for domestic cat) and was greater for indirectly transmitted pathogens. Sex was inconsistently predictive of exposure to directly transmitted pathogens only, and age infrequently predictive of both direct and indirectly transmitted pathogens. Determinants of pathogen exposure were widely divergent between the wild felid species. For puma, suburban landuse predicted increased exposure to Bartonella sp. in southern California, and FHV-1 exposure increased near urban edges in Florida. This may suggest inter-specific transmission with domestic cats via flea vectors (California) and direct contact (Florida) around urban boundaries. Bobcats captured near urban areas had increased exposure to T. gondii in Florida, suggesting an urban source of prey. Bobcats captured near urban areas in Colorado and Florida had higher FIV exposure, possibly suggesting increased intra-specific interactions through pile-up of home ranges. Beyond these regional and pathogen specific relationships, proximity to the wildland urban interface did not generally increase the probability of disease exposure in wild or domestic felids, emphasizing the importance of local ecological determinants. Indeed, pathogen exposure was often negatively associated with the wildland urban interface for all felids. Our analyses suggest cross-species pathogen transmission events around this interface may be infrequent, but followed by self-sustaining propagation within the new host species.

California, Colorado,Florida↗

USGS2021

U.S. Geological Survey landscape science strategy 2020–2030

Across our Nation, multiple Federal, State, Tribal, and local governments are working with stakeholders and landowners to restore, conserve, and manage lands and resources to benefit fish, wildlife, and people. One of the largest Federal efforts is led by the U.S. Department of the Interior (DOI), with multiple DOI agencies working to conserve and manage public lands, resources, and cultural heritage for the benefit and enjoyment of current and future generations. As a science provider within the DOI, the U.S. Geological Survey (USGS) has an important role in developing actionable science products that can inform decision making on public lands and across all of our Nation’s landscapes. Our landscapes and resources are undergoing continual change from a complex and interacting suite of stressors that include traditional and nontraditional land uses, a changing climate, a dynamic economy, and a culturally diverse and ever-changing society. Landscape science seeks to understand how the physical, biological, and social components of ecosystems and landscapes interact with each other and are affected by these stressors across local to global scales. The USGS has developed this landscape science strategy to focus and strengthen the agency’s efforts to inform critical conservation, restoration, and management decisions for American landscapes. The strategy directly supports the overarching 21st-century science strategy of the USGS and expands our perspective and focus on partnerships, including with internal, external, traditional, and nontraditional partners. The vision for USGS landscape science is to integrate multiple disciplines and approaches to create and deliver relevant, timely, and scientifically sound products that enable our partners to make informed decisions about how to manage complex interacting natural and human systems across changing American landscapes. This strategy seeks to leverage the expertise, data, analytical capacity, and tools of the agency and to strengthen integration of science efforts across programs and scales. A cornerstone of the strategy is working closely with landowners and resource managers to identify the science that is needed to inform management actions, and then working collaboratively with those same partners to coproduce science and data products that are timely, practical, and useful for their decision making. Many individual efforts within the USGS already embrace landscape science ideas and practices. With the development of this strategy, we are seeking to build on these efforts and to focus agency attention and expertise on expanding, connecting, and institutionalizing core practices and approaches for landscape science that produces actionable science products and tools that decision makers can use to help conserve and manage American landscapes.

Circular↗

USGS2019

The effects of management practices on grassland birds — An introduction to North American grasslands and the practices used to manage grasslands and grassland birds

The Great Plains of North America is defined as the land mass that encompasses the entire central portion of the North American continent that, at the time of European settlement, was an unbroken expanse of primarily herbaceous vegetation. The Great Plains extend from central Saskatchewan and Alberta to central Mexico and from Indiana to the Rocky Mountains. The expanses of herbaceous vegetation are often referred to as native prairie or native grasslands. Native grasslands share the characteristics of a general uniformity in vegetation structure, dominance by grasses and forbs, a near absence of trees and shrubs, annual precipitation ranging from 25 to 100 centimeters, extreme intra-annual fluctuations in temperature and precipitation, and a flat to rolling topography over which fires can spread. To the west of the Great Plains lie the sagebrush communities of the Great Basin, which extend from British Columbia and Saskatchewan to northern Arizona and New Mexico and from the eastern slopes of the Sierra Nevada and Cascade mountain ranges to western South Dakota. Sagebrush communities share similar characteristics to native grasslands, but their location east of the Rocky Mountains creates a more moderating influence from prevailing westerly winds that affect timing of peak precipitation and growth form of dominant vegetation. Native grasslands and sagebrush communities harbor a diverse array of grassland, wetland, and woodland plant and animal communities that are uniquely adapted to the natural forces of the Great Plains and Great Basin, namely the interactive forces of climate, fire, and grazing. The arrival of European settlers to North America brought profound change to native grassland and sagebrush communities, including the establishment of permanent towns and cities, the proliferation of cropland-based agricultural systems, and the suppression of wildfires. The near extirpation of bison by the 1860s paved the way for dramatic changes in the dominant grazers and a shift in the disturbance patterns that historically influenced vegetation structure. The greatest threat to native grasslands and sagebrush communities in modern times is their loss due to conversion to rowcrop agriculture and to urbanization. Concomitant with habitat loss is a precipitous decline in populations of bird species that evolved with, and are uniquely adapted to, the native grassland and sagebrush habitats. Avian population trends are linked strongly to agricultural land use. Besides outright loss of suitable breeding habitat, agricultural practices affect birds through factors such as pesticide exposure, habitat fragmentation, shifts in predator community composition, and occurrence of brood parasites. Bird populations face other stressors, such as loss of habitat to and behavioral avoidance of urbanized areas, roads, and infrastructure associated with energy production. Despite the many anthropogenic changes to North American grassland and sagebrush communities, some bird species are adaptable and opportunistic in their habitat selection and now utilize one or more human-created habitats. Human-created habitats include pastures, hayfields, agricultural terraces, crop buffer strips, field borders, grassed waterways, fencerows, road rights-of-way, airports, reclaimed coal mines, and planted wildlife cover. Fields of seeded grasslands enrolled in Federal long-term set-aside programs, such as the Conservation Reserve Program in the United States and the Permanent Cover Program in Canada, provide important nesting habitat for grassland bird species. The array of habitats used by birds makes habitat and avian management a complex undertaking, and the scale (for example, local, regional, international) at which management actions can be implemented are such that a universal approach to managing grasslands for the conservation of the entire suite of bird species does not exist. Experienced land managers recognize that it is impossible to manage for all bird species simultaneously, and thus, prioritization is necessary towards those habitats or bird species that the manager or management agency ranks highest for a specific region or management unit. The primary tools available for management are burning, grazing, mowing, herbicide application, and idling, but before choosing a particular practice, a manager will want to consider issues of seasonality, intensity, and frequency. Despite the thousands of studies that are cited in this compendium, much remains unknown about the effects of management practices on bird species. The series of species accounts in this compendium review the current state of knowledge regarding management of grassland and sagebrush bird species and summarize information on the effects of management practices on individual species. The accounts do not give definitive statements on the effects of management practices for any particular species, primarily because there are very few replicated studies in which identical management practices have been applied in the same geographical area with consistent results, which are elements necessary to provide concrete recommendations for the management of a particular species in a particular area. Documentation of the effects of management treatments on individual species through statistically sound methods that incorporate multiple years and locations will further scientists’ and land managers’ knowledge far more than 1–2-year studies that are limited in scope as well as time, but studies of that scope and breadth are rare.

Professional Paper↗

USGS2025

Insights and strategic opportunities from the USGS 2024 Per- and Polyfluoroalkyl Substances (PFAS) Interagency Workshop

Introduction In 2021, the U.S. Geological Survey (USGS) published Circular 1490 titled, “Integrated Science for the Study of Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS) in the Environment: A Strategic Science Vision for the U.S. Geological Survey” (Tokranov and others, 2021). Circular 1490 was created to be a resource for USGS scientists prioritizing and planning research related to per- and polyfluoroalkyl substances (PFAS) and to be a guide for developing partnerships with other scientists, State and Federal agencies, and stakeholders engaged in PFAS research and management and mitigation of the environmental and human-health effects of PFAS. This USGS PFAS Strategic Science Vision document was intended to be the foundation for a “living strategic vision,” periodically providing updates on the state of USGS PFAS research, emerging PFAS data gaps and needs, and progress on interagency and stakeholder PFAS partnerships and priorities. To meet this objective, the USGS planned to host an Interagency and Stakeholder PFAS Workshop every 2–3 years. During September 10–12, 2024, the USGS hosted the first Interagency and Stakeholder PFAS Workshop in Reston, Virginia. The Workshop brought together experts from other Federal agencies (U.S. Environmental Protection Agency, National Institute of Environmental Health Sciences, Food and Drug Administration, Department of Defense [Air Force, Army]), State agencies (Washington Fish and Wildlife, Virginia Department of Transportation), and academia (Harvard University, University of Maryland) to address key challenges relating to the measurement and modeling of PFAS and the implications for environmental health. Participants engaged in in-depth discussions centered around six pivotal topics related to PFAS: (1) sampling protocols, methods and interpretation; (2) environmental sources, source apportionment, and occurrence; (3) environmental fate and transport; (4) human and wildlife exposure routes and risk; (5) bioconcentration, bioaccumulation, and biomagnification; and (6) ecotoxicology and effects. Each topic had three breakout sessions. A recurrent theme of workshop discussions was how data on a nationwide scale for PFAS occurrence in various environmental matrices, including air, water, food crops, biota, soil, and streambed sediment could help to advance scientific understanding. Participants noted significant geospatial data gaps, particularly in the midwestern and southern United States and the Pacific Northwest. PFAS data collection tends to be more robust along the eastern seaboard and in California. Participants stressed how enhancing the integration of large and small datasets across various agencies could help to support national scale understanding of PFAS. To address these gaps, attendees suggested leveraging datasets from Federal entities like the USGS and the U.S. Department of Defense, State agencies, and municipal utility services to develop predictive contaminant detection and transport models. Improved coordination between water quality programs and USGS research could help to facilitate access to valuable data, leading to comprehensive databases that inform PFAS point (wastewater treatment plants and landfills) and nonpoint (runoff from land, atmospheric deposition, food packaging) sources, environmental transport mechanisms, environmental detection and concentrations, potential exposure routes, and health effects on different biota, including humans. A specific request was made to develop a map demarking the depth of modern (1953 or later) groundwater, which is susceptible to surface-derived anthropogenic (that is, human-made) contamination, based on tritium-age dating. Emphasis was placed on incorporation of hydrology, groundwater flow paths, groundwater–surface water interactions, and landscape factors in predictive statistical models as a step to improve contaminant source identification and tracking. Molecular fingerprinting approaches garnered attention as techniques to link specific PFAS mixtures detected in a sample to environmental sources and levels in biota (Dávila-Santiago and others, 2022). Integrating data from abiotic (that is, water, soil, and air) and biotic (that is, living organisms) systems identified as a research opportunity. For example, understanding the composition of soils and sediments, which include a mixture of mineral, plant, and animal components, could advance understanding of exposure pathways. The discussions highlighted opportunities to explore and understand the potential redistribution and biotic exposures of PFAS from biosolid and wastewater treatment plant effluent land application practices, in addition to atmospheric releases and discharges from landfill and wastewater treatment plants. Participants identified research gaps surrounding how these sources may contribute to contamination and may affect surrounding ecosystems, including a better definition of anthropogenic background concentrations. Moving forward, the collection of co-occurrence data was noted as a means to improve understanding of complex mixtures and to leverage companion modeling efforts focused on areas with high and low contamination levels to identify areas of concern and unaffected resources. Participants emphasized how centralized USGS databases and the establishment of sample-metadata archives can help to ensure that samples are preserved and accessible for future research. In conclusion, the workshop participants identified opportunities to bridge data gaps and improve measurement techniques, modeling frameworks, databases, and communication, to enhance the understanding of PFAS and their effects on environmental and human health. Upon completion of the workshop, participants indicated an interest in developing strategic data collection, modeling, and analytical approaches to address these challenges.

Open-File Report↗

USGS2021

Sagebrush conservation strategy—Challenges to sagebrush conservation

The sagebrush ( Artemisia spp.) biome, its wildlife, and the services and benefits it provides people and local communities are at risk. Development in the sagebrush biome, for many purposes, has resulted in multiple and often cumulative negative impacts. These impacts, ranging from simple habitat loss to complex, interactive changes in ecosystem function, continue to accelerate even as the need grows for the resources provided by this biome. This “Sagebrush Conservation Strategy—Challenges to Sagebrush Conservation,” is an overview and assessment of the challenges facing land managers and landowners in conserving sagebrush ecosystems. This strategy is intended to provide guidance so that the unparalleled collaborative efforts to conserve the iconic greater sage-grouse ( Centrocercus urophasianus ) by State and Federal agencies, Tribes, academia, nongovernmental organizations, and stakeholders can be expanded to the entire sagebrush biome to benefit the people and wildlife that depend on this ecosystem. This report is organized into 3 parts. “Part I. Importance of the Sagebrush Biome to People and Wildlife” introduces the biome and a subset of the more than 350 species of plants and animals associated with sagebrush for which there is some level of conservation concern. These include several sagebrush obligates that have been petitioned for listing under the Endangered Species Act of 1973 (16 U.S.C. 1531 et seq.), including greater sage-grouse, Gunnison sage-grouse ( C. minimus ; listed as threatened), and pygmy rabbit ( Brachylagus idahoensis ). Other sagebrush-dependent species, such as pronghorn ( Antilocapra americana ) and mule deer ( Odocoileus hemionus ), have experienced significant population declines. “Part II. Change Agents in the Sagebrush Biome—Extent, Impacts, and Effort to Address Them” is an overview of the variety of change agents that are causing the continued loss and degradation of sagebrush. Topics covered include altered fire regimes, invasive plant species, conifer expansion, overabundant free-roaming equids, and human land uses, including energy development, cropland conversion, infrastructure, and improper livestock grazing. Climate changes, including warmer temperatures and altered amounts and timing of precipitation, have and will likely increasingly compound negative effects to sagebrush ecosystems from all these threats. “Part III. Current Conservation Paradigm and Other Conservation Needs for Sagebrush” begins with an overview of how sage-grouse conservation, and the associated efforts and collaborations, may be able to address threats to and restoring degraded sagebrush and habitat for other sagebrush-dependent and -associated species. Meeting conservation goals for sage-grouse, mule deer, pygmy rabbits, and other sagebrush-associated wildlife will require extensive restoration of sagebrush communities already converted or degraded by the change agents outlined in Part II of this report. Concepts, considerations, techniques for restoration, and adaptive management and monitoring are discussed to help set the stage for potential strategies to improve conditions throughout the sagebrush biome. Communication, outreach, and engagement can enhance grassroots conservation efforts and build the next generation of managers, practitioners, scientists, and communicators who will care for the sagebrush ecosystem and stimulate or sustain public participation in sagebrush conservation issues.

Arizona, California, Colorado, Idaho, Montana, Neb↗

USGS2005

Public acceptance of management actions and judgments of responsibility for the wolves of the southern Greater Yellowstone Area: Report to Grand Teton National Park

Introduction Wolves of Grand Teton National Park and the Greater Yellowstone Area Gray wolves (Canis lupus) appeared in Grand Teton National Park (GRTE) in October of 1998, two years after being reintroduced to Yellowstone National Park (YNP). Since that time, five packs have been within the GRTE borders - Gros Ventre Pack, Nez Perce Pack, Yellowstone Delta Pack, Teton Pack, and Green River Pack (Table 1). Wolves in the Greater Yellowstone Area are increasing and spreading out geographically (USFWS and others, 2004). This dispersion was demonstrated recently by the death of a 2-year-old female wolf from the Swan Lake pack on I-70 in Colorado (June 7, 2004; http://mountain-prairie.USFWS.gov/pressrel /04-43.htm). The organization of wolf packs in the GYA is dynamic and highly structured. In 2003, for example, a wolf from the Teton Pack joined with the Green River Pack, and several young wolves left the Teton Pack and moved south (USFWS and others, 2004). Pack size (averaging five to ten members) is dependent on hunting efficiency, which depends on prey size, type, and density. Each pack defends home ranges of several hundred square miles. The social structure of the pack is based on a breeding pair (an alpha male and female). Other wolves in the pack can be categorized as betas (males and/or females second in rank to the alphas), subordinates, pups, and occasional omegas (outcasts). Because generally only the alpha pair breeds, subordinate wolves of reproductive age must disperse from their packs and form new associations in order to breed. (http://www.nps.gov/grte/wolf/biolo.htm). The reintroduced wolves are classified by the U.S. Fish and Wildlife Service (USFWS) as "nonessential experimental" under section 10(j) of the Endangered Species Act. The recovery criteria for the GYA wolves were met in 2002 for removing the wolves from the Endangered Species List (30 or more breeding pairs). Currently, the USFWS manages wolf populations in the GYA until delisting occurs. After delisting, state Fish and Wildlife Services in Montana, Idaho, and Wyoming will be responsible for managing wolves. Each state must submit a wolf management plan to the USFWS which then must be approved before management shifts occur. As of this writing, the process of delisting the wolves in the state of Wyoming is ongoing. However, the reclassification of wolves nationwide was completed on April 1, 2003. Wolves outside of YNP changed in status from endangered to threatened. The wolves classified in the experimental nonessential population did not change in status (USFWS and others, 2004). This classification of experimental nonessential population allows for flexibility in management decisions concerning the wolves (Smith and others, 2004). For example, control actions in the GYA included trapping and radio-collaring four wolves; intensive monitoring; increasing riders on grazing allotments; harassing wolves with rubber bullets, cracker shells, and lights; moving livestock to different pastures; and issuing four shoot on-sight permits. When non-lethal control methods were not effective, wolves were killed in an attempt to prevent further livestock depredations (USFWS and others, 2004; Table 1). At the same time that wolf numbers are rising, human population statistics in the GRTE area are also rising. The population of Teton County, Wyoming in 1990 was just over 11,000 people; today that number has increased to approximately 19,000 (U.S. Census Bureau, 2005). park visitation for GRTE has been substantial over the last several years with an average visitation of 2.5 million visitors (NPS, 2004a). Furthermore, land ownership surrounding GRTE and the establishment of grazing rights within park boundaries are problem areas for wolf-human interactions due to livestock depredation. With increasing numbers of visitors, residents, and livestock it is reasonable to assume that conflicts are going to increase also. In 1950, GRTE was expanded to in

Open-File Report↗

USGS2016

Seeing the forest through the trees: Considering roost-site selection at multiple spatial scales

Conservation of bat species is one of the most daunting wildlife conservation challenges in North America, requiring detailed knowledge about their ecology to guide conservation efforts. Outside of the hibernating season, bats in temperate forest environments spend their diurnal time in day-roosts. In addition to simple shelter, summer roost availability is as critical as maternity sites and maintaining social group contact. To date, a major focus of bat conservation has concentrated on conserving individual roost sites, with comparatively less focus on the role that broader habitat conditions contribute towards roost-site selection. We evaluated roost-site selection by a northern population of federally-endangered Indiana bats ( Myotis sodalis ) at Fort Drum Military Installation in New York, USA at three different spatial scales: landscape, forest stand, and individual tree level. During 2007–2011, we radiotracked 33 Indiana bats (10 males, 23 females) and located 348 roosting events in 116 unique roost trees. At the landscape scale, bat roost-site selection was positively associated with northern mixed forest, increased slope, and greater distance from human development. At the stand scale, we observed subtle differences in roost site selection based on sex and season, but roost selection was generally positively associated with larger stands with a higher basal area, larger tree diameter, and a greater sugar maple ( Acer saccharum ) component. We observed no distinct trends of roosts being near high-quality foraging areas of water and forest edges. At the tree scale, roosts were typically in American elm ( Ulmus americana ) or sugar maple of large diameter (>30 cm) of moderate decay with loose bark. Collectively, our results highlight the importance of considering day roost needs simultaneously across multiple spatial scales. Size and decay class of individual roosts are key ecological attributes for the Indiana bat, however, larger-scale stand structural components that are products of past and current land use interacting with environmental aspects such as landform also are important factors influencing roost-tree selection patterns.

PLoS ONE↗

USGS2018

Effect of climate change on disease spread in wildlife

A growing body of evidence indicates that climate change alone, or acting synergistically with current anthropogenic threats, is affecting the health of wild populations of aquatic and terrestrial wildlife. Measurable by-products of climate change include elevated atmospheric concentrations of greenhouse gases, higher average global temperatures; variations in global precipitation patterns, rising and warming oceans, altered hydrographs of rivers, and increased mid-continental drying during summer. These consequences affect the terrestrial environment through shifts in phenology, vegetation cover, and fire regimes. Warmer ocean temperatures, increased acidification, rise in sea levels, and reduction in sea ice cover are also leading to widespread ecological changes in marine systems. Wildlife populations face a variety of climate-related pressures, such as changes in animal distribution or density, limitation of food resources, and alteration to critical habitats. The increased potential for emergence and resurgence of diseases that are responsive to environmental conditions also has implications for wildlife populations. Shifts in temperature or other climatic factors may directly affect the incidence of disease in wildlife by altering host-pathogen interactions, promoting vector populations or allowing new ranges for vectors, or reducing development times for parasites. A number of examples from both field and laboratory studies have demonstrated a clear link between warming environments and disease spread. Many climate-related environmental changes also influence wildlife health indirectly. For example, increasing temperatures, in combination with shifts in rainfall and humidity, may aggravate current trends for water resource limitation and habitat degradation or destruction and lead to increased crowding of animal populations, thereby promoting transmission opportunities of pathogens within populations or across species. Although it may be difficult to disentangle the influences of other anthropogenic changes from the direct effects of warming, some ecosystems provide especially useful models for studying climate-related disease spread in wildlife. For example, the effects of climate change on parasite dynamics may be easily observed in the Arctic, where environmental changes are occurring rapidly, anthropogenic influences are relatively limited, and biodiversity is generally low. Marine ecosystems are also undergoing rapid rates of change and may be vulnerable to a variety of natural and anthropogenic perturbations. Although many factors affect the health of organisms in ocean environments, temperature has been clearly linked to an increase in disease prevalence among sessile organisms such as corals. In this chapter, we discuss observed and predicted changes to wildlife health resulting from climate change. Our review will not include all aspects of wildlife health, but will instead focus on established or suspected links between climate drivers and disease spread and discuss examples from the current literature. Here, we define disease spread to include: 1) change in geographical or altitudinal distribution of pathogens, parasites, and vectors and the diseases they cause; 2) change in prevalence or severity of disease; and 3) emergence of novel diseases. Additionally, because wildlife species serve as reservoirs for zoonotic diseases that affect both animals and humans, we include select examples of the effect of climate change on the capacity of wildlife to harbor and spread these disease agents.

Book chapter↗

USGS2019

Public access for pheasant hunters: Understanding an emerging need

Ring-necked pheasant ( Phasianus colchicus ; i.e., pheasant) hunting participation is declining across North America, reflecting a larger downward trend in American hunting participation and threatening benefits to grassland conservation and rural economies. To stabilize and expand the pheasant hunting population, we must first identify factors that influence pheasant hunter participation. We used an extensive in-person hunter survey to test the hypothesis that hunter demographics interact with social-ecological traits of hunting locations to affect hunter decisions, outcomes, and perceptions. We built a series of Bayesian mixed effects models to parse variation in demographics, perceptions, and hunt outcomes of pheasant hunters interviewed at public access hunting sites across 3 regions in Nebraska, USA, that varied in pheasant abundance and proximity to urban population centers. Among pheasant hunters in Nebraska, access to private lands was negatively related to the human population density of a pheasant hunter's home ZIP code and the distance a hunter had traveled to reach a hunting location. Pheasant hunters interviewed closer to metropolitan areas tended to be more urban and travel shorter distances, and their parties were more likely to include youth but less likely to include dogs. Hunter satisfaction was positively associated with seeing and harvesting pheasants and hunting with youth. Whereas youth participation and the number of pheasants seen varied by study region, hunter satisfaction did not differ across regions, suggesting that hunters may calibrate their expectations and build their parties based on where they plan to hunt. The variation in hunter demographics across hunting locations and disconnects between social and ecological correlates of hunter satisfaction suggests that diverse pheasant hunting constituencies will be best served by diverse pheasant hunting opportunities.

Nebraska↗

USGS2007

Proceedings of the Fourth Glacier Bay Science Symposium

Foreword Glacier Bay was established as a National Monument in 1925, in part to protect its unique character and natural beauty, but also to create a natural laboratory to examine evolution of the glacial landscape. Today, Glacier Bay National Park and Preserve is still a place of profound natural beauty and dynamic landscapes. It also remains a focal point for scientific research and includes continuing observations begun decades ago of glacial processes and terrestrial ecosystems. In recent years, research has focused on glacial-marine interactions and ecosystem processes that occur below the surface of the bay. In October 2004, Glacier Bay National Park convened the fourth in a series of science symposiums to provide an opportunity for researchers, managers, interpreters, educators, students and the general public to share knowledge about Glacier Bay. The Fourth Glacier Bay Science Symposium was held in Juneau, Alaska, rather than at the Park, reflecting a desire to maximize attendance and communication among a growing and diverse number of stakeholders interested in science in the park. More than 400 people attended the symposium. Participants provided 46 oral presentations and 41 posters covering a wide array of disciplines including geology, glaciology, oceanography, wildlife and fisheries biology, terrestrial and marine ecology, socio-cultural research and management issues. A panel discussion focused on the importance of connectivity in Glacier Bay research, and keynote speakers (Gary Davis and Terry Chapin) spoke of long-term monitoring and ecological processes. These proceedings include 56 papers from the symposium. A summary of the Glacier Bay Science Plan-itself a subject of a meeting during the symposium and the result of ongoing discussions between scientists and resource managers-also is provided. We hope these proceedings illustrate the diversity of completed and ongoing scientific studies, conducted within the Park. To this end, we invited all presenters to submit brief technical summaries of their work, to capture the gist of their study and its main findings without an overload of details and methodology. We also asked authors to include a few words on the management implications of their work to help bridge the gap between scientists and managers in understanding how specific research questions may translate to management practice. Papers in this volume are laid out by subject matter, from terrestrial and freshwater subjects to glacial-marine geology, to the ecology of marine animals and ending with risk assessment, human impacts and science-management considerations. In summary, we hope the proceedings will serve as a useful reference to completed and ongoing studies in Glacier Bay National Park, and thereby provide park enthusiasts, scientists, and managers with a road map of scientific progress.

Scientific Investigations Report↗

USGS2015

Influences of supplemental feeding on winter elk calf:cow ratios in the southern Greater Yellowstone Ecosystem

Several elk herds in the Greater Yellowstone Ecosystem are fed during winter to alleviate interactions with livestock, reduce damage to stored crops, and to manage for high elk numbers. The effects of supplemental feeding on ungulate population dynamics has rarely been examined, despite the fact that supplemental feeding is partially justified as necessary for maintaining or enhancing population growth rates. We used linear regression to assess how the presence of feedgrounds, snowpack, summer rainfall, indices of grizzly bear density and wolves per elk, elk population trend counts, brucellosis seroprevalence, and survey date were correlated with midwinter calf:cow ratios, a metric correlated with population growth, from 1983–2010 from 12 ecologically similar elk herd units (7 fed and 5 unfed) in Wyoming, USA. Our statistical approach allowed for rigorous tests of the hypotheses that supplemental feeding had positive effects on calf:cow ratios and reduced sensitivity of calf:cow ratios to bottom-up limitation relative to top-down limitation from native predators. Calf:cow ratios generally declined across all herd units over the study period and varied widely among units with feedgrounds. We found no evidence that the presence of feedgrounds had positive effects on midwinter calf:cow ratios in Wyoming. Further, fed elk showed stronger correlations with environmental factors, whereas calf:cow ratios for unfed elk showed stronger correlations with predator indices. Although we found no consistent association between winter feeding and higher calf:cow ratios, we did not assess late winter mortality and differences in human offtake between fed and unfed regions, which remain a priority for future research.

Wyoming↗

USGS2006

Comparison of methods used to diagnose generalized inflammatory disease in manatees (Trichechus manatus latirostris)

Manatees ( Trichechus manatus latirostris ) are afflicted with inflammatory and infectious disease secondary to human interaction, such as boat strike and entanglement, as well as “cold stress syndrome” and pneumonia. White-blood-cell count and fever, primary indicators of systemic inflammation in most species, are insensitive in diagnosing inflammatory disease in manatees. Acute phase-response proteins, such as haptoglobin and serum amyloid A, have proven to be sensitive measures of inflammation/infection in domestic large animal species. This study assessed diagnosis of generalized inflammatory disease by different methods including total white-blood-cell count, albumin: globulin ratio, gel electrophoresis analysis, C-reactive protein, alpha 1 acid glycoprotein, haptoglobin, fibrinogen, and serum amyloid A. Samples were collected from 71 apparently healthy and 27 diseased animals during diagnostic medical examination. Serum amyloid A, measured by ELISA, followed by albumin:globulin ratio, measured by plasma gel electrophoresis, were most sensitive in diagnosing inflammatory disease, with diagnostic sensitivity and specificity of approximately 90%. The reference interval for serum amyloid A is <10–50 μg/ml with an equivocal interval of 51–70 μg/ml. The reference interval for albumin:globulin ratio by plasma gel electrophoresis is 0.7–1.1. Albumin: globulin ratio, calculated using biochemical techniques, was not accurate due to overestimation of albumin by bromcresol green dye-binding methodology. Albumin:globulin ratio, measured by serum gel electrophoresis, has a low sensitivity of 15% due to the lack of fibrinogen in the sample. Haptoglobin, measured by hemoglobin titration, had a reference interval of 0.4–2.4 mg/ml, a diagnostic sensitivity of 60%, and a diagnostic specificity of 93%. The haptoglobin assay is significantly affected by hemolysis. Fibrinogen, measured by heat precipitation, has a reference interval of 100–400 mg/dl, a diagnostic sensitivity of 40%, and a diagnostic specificity of 95%.

Journal of Zoo and Wildlife Medicine↗

USGS2022

Modeling the spatial and temporal dynamics of land-based polar bear denning in Alaska

Although polar bears ( Ursus maritimus ) of the Southern Beaufort Sea (SBS) subpopulation have commonly created maternal dens on sea ice in the past, maternal dens on land have become increasingly prevalent as sea ice declines. This trend creates conditions for increased human–bear interactions associated with local communities and industrial activity. Maternal denning is a vulnerable period in the polar bear life cycle, and den disturbance could lead to den abandonment, cub mortality, and negative population impacts. We used published long-term data to parameterize a Bayesian hierarchical model of annual land den abundance during 2000–2015, in 4 regions of northern Alaska, USA, with current or potential future oil and gas activity. We also estimated long-term (1982–2015) shifts in the spatial distribution of land dens within and among regions using kernel density estimation and assessed the influence of local and regional sea ice and snow conditions on den site selection using a random forest resource selection function. Our objectives were to quantify current den distribution and abundance, test for distributional shifts over time, and investigate if those shifts could be attributed to environmental variables related to den habitat. We estimated that between 2000 and 2015, the SBS contained a median 123 dens in a typical year, of which 68 occurred on land. The region between the Colville and Canning rivers, where most current oil and gas activity occurred, also contained the largest fraction of land dens. Overall, land dens were disproportionately concentrated on barrier islands and on land within 30 km of the coast. The probability of dens occurring on land varied from 1982–1999 to 2000–2015 in all regions, and the overall distribution of land dens shifted west between those periods. This regional-scale change in den distribution was predictable based on spatial and temporal heterogeneity in snow and sea ice conditions within 50 km of individual den locations. Land denning is likely to become increasingly common with continued sea ice loss, and our results and modeling framework could be used to design additional mitigation strategies for reducing the risk of incidental take due to den disturbance.

Alaska↗

USGS1999

Reference intervals and physiologic alterations in hematologic and biochemical values of free-ranging desert tortoises in the Mojave Desert

Desert tortoise ( Gopherus agassizii ) populations have experienced precipitous declines resulting from the cumulative impact of habitat loss, and human and disease-related mortality. Evaluation of hematologic and biochemical responses of desert tortoises to physiologic and environmental factors can facilitate the assessment of stress and disease in tortoises and contribute to management decisions and population recovery. The goal of this study was to obtain and analyze clinical laboratory data from free-ranging desert tortoises at three sites in the Mojave Desert (California, USA) between October 1990 and October 1995, to establish reference intervals, and to develop guidelines for the interpretation of laboratory data under a variety of environmental and physiologic conditions. Body weight, carapace length, and venous blood samples for a complete blood count and clinical chemistry profile were obtained from 98 clinically healthy adult desert tortoises of both sexes at the Desert Tortoise Research Natural area (western Mojave), Goffs (eastern Mojave) and Ivanpah Valley (northeastern Mojave). Samples were obtained four times per year, in winter (February/March), spring (May/June), summer (July/August), and fall (October). Years of near-, above- and below-average rainfall were represented in the 5 yr period. Minimum, maximum and median values, and central 95 percentiles were used as reference intervals and measures of central tendency for tortoises at each site and/or season. Data were analyzed using repeated measures analysis of variance for significant ( P < 0.01) variation on the basis of sex, site, season, and interactions between these variables. Significant sex differences were observed for packed cell volume, hemoglobin concentration, aspartate transaminase activity, and cholesterol, triglyceride, calcium, and phosphorus concentrations. Marked seasonal variation was observed in most parameters in conjunction with reproductive cycle, hibernation, or seasonal rainfall. Year-to-year differences and long-term alterations primarily reflected winter rainfall amounts. Site differences were minimal, and largely reflected geographic differences in precipitation patterns, such that results from these studies can be applied to other tortoise populations in environments with known rainfall and forage availability patterns.

Journal of Wildlife Diseases↗

USGS2008

Hydrology Prior to Wetland and Prairie Restoration in and around the Glacial Ridge National Wildlife Refuge, Northwestern Minnesota, 2002-5

The Nature Conservancy (TNC) owned and managed 24,795 acres of mixed wetland, native prairie, farmland and woods east of Crookston, in northwestern Minnesota. The original wetlands and prairies that once occupied this land are being restored by TNC in cooperation with many partners and are becoming part of the Glacial Ridge National Wildlife Refuge. Results of this study indicate that these restorations are likely to have a substantial effect on the local hydrology. Water occurs within the study area on the land surface, in surficial aquifers, and in buried aquifers of various depths, the tops of which are 50 to several hundred feet below the land surface. Surficial aquifers are generally thin (about 20 feet), narrow (several hundred feet), and long (tens of miles). Estimates of the horizontal hydraulic conductivity of surficial aquifers were 2.7?300 feet per day. Buried aquifers underlie much of the study area, but interact with surficial aquifers only in isolated areas. In these areas, water flows directly from buried to surficial aquifers and forms a single aquifer as much as 78 feet thick. The surface?water channel network is modified by several manmade ditches that were installed to remove excess water seasonally and to drain wetlands. The channels of the network lie primarily parallel to the beach ridges but cut through them in places. Back?beach basin wetlands delay and reduce direct runoff to ditches. Recharge to the surficial aquifers (10.97?25.08 inches per year during 2003?5) is from vertical infiltration of rainfall and snowmelt (areal recharge); from surface waters (particularly ephemeral wetlands); and from upward leakage of water from buried aquifers through till confining units (estimated at about 1 inch per year). Areal recharge is highly variable in space and time. Water leaves (discharges from) the surficial aquifers as flow to surface waters (closed basins and ditches), evapotranspiration, and withdrawals from wells. Unmeasured losses (primarily discharge to ungaged (closed) basins) were 53?115 percent of areal recharge during 2003?5, while discharge to ditches that leave the study area was 17?41 percent. Discharge over 100 percent of areal recharge indicates a loss in ground?water storage. During the dry year of 2003, substantial ground water (about one?third of annual areal recharge) was released from aquifer storage but was replenished quickly during the subsequent normal year. Shallow ground?water flow is complex, with water in surficial aquifers, ditches, and wetlands part of a single hydrologic system. The ages determined for surficial ground?water samples were less than 15 years old, and one?third (8 of 24) were less than 5 years old, substantiating the close connection of surficial ground water to the land surface. During the study, 68?81 percent of water left the area through unmeasured surface?water losses (primarily evapotranspiration), which is 2? to 4?times that leaving through the ditch system. Base flow in ditches (ground?water discharge) was 30 to 71 percent of all ditch flow. Mean annual runoff in all gaged basins except SW3 (2.26 inches per year) was similar (3.69?4.12 inches per year). The quality of water samples from surficial aquifers and surface water collected in the study area was generally suitable for most uses but was variable. Most ground? and surface?water samples were dominated by calcium, magnesium, and bicarbonate ions. About one?quarter of surficial ground?water samples contained nitrate at concentrations greater than the U.S. Environmental Protection Agency?s (USEPA) Maximum Contaminant Level for human consumption. The median concentration of dissolved phosphorus ranged from 0.0108 milligrams per liter as phosphorus (mg/L?P) to 0.0293 mg/L?P. Nutrient concentrations in ditches were generally above the USEPA nutrient guidelines for reference streams in the area. Water samples contained detectable concentrations of atrazine, acetachlor, metolachlor, pendimethalin

Scientific Investigations Report↗