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USGS2012

Book review: The requisite reference for the study of Sirenia

Sirenians often are given little or no notice in texts on marine mammals; whales, dolphins, and seals are what come to mind for most when a marine mammal is imagined. An order of only four extant species, the Sirenia is indeed the “other” frequently overlooked group of marine mammals. Dugongs and manatees remain unknown by much of the world, but to those that study these species, the members are extraordinarily unique and fascinating. The three highly respected authors of this newly published volume are all distinguished researchers, with more than a century of combined expertise in the study of this mammalian order. Their collective experience and insight make this book a captivating and valuable read for students, professionals, and anyone interested in having an all-inclusive reference for learning about the Order Sirenia. Review info: Ecology and conservation of the Sirenia-dugongs and manatees . By H. Marsh, T. J. O'Shea, and J. E. Reynolds, III, 2012. ISBN: 978-0521888288, 521 pp.

Journal of Mammalian Evolution↗

USGS1998

Satellite telemetry: A new tool for wildlife research and management

The U.S. Fish and Wildlife Service and the Alaska Department of Fish and Game have cooperated since 1984 to develop and evaluate satellite telemetry as a means of overcoming the high costs and logistical problems of conventional VHF (very high frequency) radiotelemetry systems. Detailed locational and behavioral data on caribou ( Rangifer tarandus ), polar bears ( Ursus maritimus ), and other large mammals in Alaska have been obtained using the Argos Data Collection and Location System (DCLS). The Argos system, a cooperative project of the Centre National d'Études Spatiales of France, the National Oceanic and Atmospheric Administration, and the National Aeronautics and Space Administration, is designed to acquire environmental data on a routine basis from anywhere on earth. Transmitters weighing 1.6-2.0 kg and functioning approximately 12-18 months operated on a frequency of 401.650 MHz. Signals from the transmitters were received by Argos DCLS instruments aboard two Tiros-N weather satellites in sun-synchronous, nearpolar orbits. Data from the satellites were received at tracking stations, transferred to processing centers in Maryland and France, and made available to users via computer tape, printouts, or telephone links. During 1985 and 1986, more than 25,000 locations and an additional 28,000 sets of sensor data (transmitter temperature and short-term and long-term indices of animal activity) were acquired for caribou and polar bears. Locations were calculated from the Doppler shift in the transmitted signal as the satellite approached and then moved away from the transmitter. The mean locational error for transmitters at known locations (n - 1,265) was 829 m; 90% of the calculated locations were within 1,700 m of the true location. Caribou transmitters provided a mean of 3.1 (+5.0. SD) locations per day during 6h of daily operation, and polar bear transmitters provided 1.7 (+6.9SD) locations during 12h of operation every third day. During the first 6 months of operation, the UHF (ultra-high frequency) signal failed on three of 32 caribou transmitters and 10 of 36 polar bear transmitters. A geographic information system (GIS) incorporating other databases (e.g., land cover, elevation, slope, aspect, hydrology, ice distribution) was used to analyze and display detailed locational and behavioral data collected via satellite. Examples of GIS applications to research projects using satellite telemetry and examples of detailed movement patterns of caribou and polar bears are presented. This report includes documentation for computer software packages for processing Argos data and presents developments, as of March 1987, in transmitter design, data retrieval using a local user terminal, computer software, and sensor development and calibration.

Resource Publication↗

USGS2006

Comparison of methods used to estimate numbers of walruses on sea ice

The US and former USSR conducted joint surveys of Pacific walruses on sea ice and at land haul-outs in 1975, 1980, 1985, and 1990. One of the difficulties in interpreting results of these surveys has been that, except for the 1990 survey, the Americans and Soviets used different methods for estimating population size from their respective portions of the sea ice data. We used data exchanged between Soviet and American scientists to compare and evaluate the two estimation procedures and to derive a set of alternative estimates from the 1975, 1980, and 1985 surveys based on a single consistent procedure. Estimation method had only a small effect on total population estimates because most walruses were found at land haul-outs. However, the Soviet method is subject to bias that depends on the distribution of the population on the sea ice and this has important implications for interpreting the ice portions of previously reported surveys for walruses and other pinniped species. We recommend that the American method be used in future surveys. Future research on survey methods for walruses should focus on other potential sources of bias and variation.

Chukchi Sea↗

USGS2023

Effects of feeding and habitat on resting metabolic rates of the Pacific walrus

Arctic marine mammals live in a rapidly changing environment due to the amplified effects of global warming. Pacific walruses ( Odobenus rosmarus divergens ) have responded to declines in Arctic sea-ice extent by increasingly hauling out on land farther from their benthic foraging habitat. Energy models can be useful for better understanding the potential implications of changes in behavior on body condition and reproduction but require behavior-specific metabolic rates. Here we measured the resting metabolic rates (RMR) of three captive, adult female Pacific walruses through breath-by-breath respirometry when fed and fasted resting out of water (sitting and lying down) and while fed resting in water. RMR in and out of water were positively related with pretrial energy intake when not fasted and 25% higher than RMR when walruses were fasted and out of water. Overall, RMR was higher than previously estimated for this species. Fasting RMR out of water was only 25% lower than subsurface swimming metabolic rates suggestive of relatively efficient swimming in adult females. Our results identify the importance of considering feeding status and species-specific differences in affecting metabolic costs. Further research is needed to better understand potential energetic costs of thermoregulation at temperatures experienced by wild walruses.

Valencia↗

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↗

USGS1979

Exploitation of marine mammals: r-selection of K-strategists?

The importance of marine mammals as predators to the organization of marine communities is poorly known, although in several structurally analogous systems the ecological and evolutionary roles of predators are known to be of considerable importance. Occupation of the marine environment by mammals probably carried physiological constraints for single-young pregnancies thereby limiting all species to low intrinsic rates of population increase. As such, species subjected to high mortality rates from predation or other natural disturbances became extinct; those that survived probably were largely resource limited. In view of this scenario it is suggested that stable populations of marine mammals can be maintained at high levels without being manipulated in most communities. Exploitation probably constitutes a rather dramatic environmental change to marine mammals consequently subjecting them to selective forces fundamentally different from many of those under the influence of which they evolved.

Journal of the Fisheries Research Board of Canada↗

USGS2020

How and why is the timing and occurrence of seasonal migrants in the Gulf of Maine changing due to climate?

Plants and animals undergo certain recurring life-cycle events, such as migrations between summer and winter habitats or the annual blooming of plants. Known as phenology, the timing of these events is very sensitive to changes in climate (and changes in one species’ phenology can impact entire food webs and ecosystems). Shifts in phenology have been described as a “fingerprint” of the temporal and spatial responses of wildlife to climate change impacts. Thus, phenology provides one of the strongest indicators of the adaptive capacity of organisms (or the ability of organisms to cope with future environmental conditions). In this study, researchers are exploring how the timing and occurrence of a number of highly migratory marine animals is changing due to a series of climatic and ecological shifts. First, using existing long-term historical data series, they will determine the direction and magnitude of how migration, abundance, or other phenological factors have changed for marine mammals, sea turtles, and fishes that migrate into the Gulf of Maine on a seasonal basis. Because marine animals are inherently difficult to detect, the team will apply dynamic occupancy models to evaluate seasonal migration patterns and habitat use across multiple habitats in the Gulf of Maine region. The project team will also synthesize regional information on a key, ecologically-important prey fish, sandlance, whose timing and abundance is a strong predictor of the occurrence and behavior of predator species targeted in this study as well as a range of other regional fish and wildlife of conservation and management concern. Results from this component of the project will identify coastal fish and wildlife species that are relatively more or less able to adapt and thus potentially vulnerable to climate change; determine the likely primary drivers of those changes; and identify data gaps and future monitoring needs. Ultimately, this information will be available and useful for regional coastal management and adaptation decisions that will allow managers to effectively plan for the future. In a second component of the project, researchers will focus specifically on changes in migration patterns of the endangered North Atlantic right whale. While shifts in the distribution and time of recurring life events are adaptive responses that may help species cope with climate impacts, they can also lead to changes in how species interact with humans. The North Atlantic right whale is one of the most endangered whale species on the planet. In the North Atlantic Ocean, ship strikes and entanglements with commercial fishing gear represent fatal threats to right whales. Recent reports suggest that North Atlantic right whale migration patterns have changed. Many researchers posit that shifts in migration are responsible for recent increases in the overlap between right whales and human activities, especially fishing. To help understand how changes in right whale movements and behaviors may overlap with ship traffic, and thus put the animals at risk of encountering vessels, we will combine right whale habitat models with ship traffic maps. The end result will be a set of maps identifying risk levels.

Gulf of Maine↗

USGS2006

Vascular Plant and Vertebrate Inventory of Casa Grande Ruins National Monument

Executive Summary This report summarizes results of the first comprehensive biological inventory of Casa Grande Ruins National Monument (NM) in southern Arizona. Surveys at the monument were part of a larger effort to inventory vascular plants and vertebrates in eight National Park Service units in Arizona and New Mexico. In 2001 and 2002 we surveyed for vascular plants and vertebrates (amphibians, reptiles, birds, and mammals) at Casa Grande Ruins NM to document the presence, and in some cases relative abundance, of species. By using repeatable study designs and standardized field techniques, which included quantified survey effort, we produced inventories that can serve as the basis for a biological monitoring program. Of the National Park Service units in the region, no other has experienced as much recent ecological change as Casa Grande Ruins NM. Once situated in a large and biologically diverse mesquite bosque near the perennially flowing Gila River, the monument is now a patch of sparse desert vegetation surrounded by urban and commercial development that is rapidly replacing agriculture as the dominant land use in the area. Roads, highways, and canals surround the monument. Development, and its associated impacts, has important implications for the plants and animals that live in the monument. The plant species list is small and the distribution and number of non-native plants appears to be increasing. Terrestrial vertebrates are also being impacted by the changing landscape, which is increasing the isolation of these populations from nearby natural areas and thereby reducing the number of species at the monument. These observations are alarming and are based on our review of previous studies, our research in the monument, and our knowledge of the biogeography and ecology of the Sonoran Desert. Together, these data suggest that the monument has lost a significant portion of its historic complement of species and these changes will likely intensify as urbanization continues. Despite isolation of the monument from nearby natural areas, we recorded noteworthy species or observations for all taxonomic groups: * Plants: night-blooming cereus * Amphibians: high abundance of Couch's spadefoot toads * Reptiles: high abundance of long-nosed snakes * Birds: 10 species of diurnal raptors including 4 species of falcons * Mammals: American badger This study is a first step in the process of compiling information about the biological resources of Casa Grande Ruins NM and surrounding areas. We recommend additional inventory and research studies, and we identify aspects of our effort that could be improved upon through application of new techniques or by extending the temporal (and possibly spatial) scope of our work.

Open-File Report↗

USGS2018

American Recent Eulipotyphla: Nesophontids, Solenodons, Moles, and Shrews in the New World

The mammalian taxonomic order Eulipotyphla is comprised of the living taxonomic families Erinaceidae (gymnures, hedgehogs, and moonrats), Solenodontidae (solenodonts), Soricidae (shrews), and Talpidae (desmans and moles). Morphological and molecular studies continue to alter our view of relationships within and among these families, and this research has added considerably to our understanding of the diversity, distributions, and relationships of many of the New World species that belong to them. Currently, there are more than 450 recognized living species worldwide, making the Eulipotyphla the third most speciose order of mammals. New World (North and South America and associated islands) eulipotyphlans currently include 110 recognized species of shrews, seven species of moles, and both living species of solenodons. In this work, I attempt to summarize the taxonomic results of recent studies and provide a guide to the most appropriate current applications of taxonomic names in this region.

Book↗

USGS2025

Mechanisms influencing thermal refuges and territory occupancy by collared pikas during summer and winter

Collared pikas ( Ochotona collaris ) are cold adapted alpine lagomorphs of western Canada and Alaska, USA, that are vulnerable to direct and indirect effects of climate change. However, how and to what extent such changes influence persistence for this species is not well understood, particularly at fine spatial scales. Our goal was to evaluate how microclimate and microhabitat characteristics influence occupancy of collared pikas. We quantified thermal conditions during both summer and winter to test hypotheses about potential drivers of pika persistence. We recorded den occupancy and territory characteristics, including in situ measurements of den microclimate, across three study areas with contrasting climate gradients in southcentral and interior Alaska during 2017–2022. We examined changes in pika den occurrence by estimating annual colonization and extinction rates with a Bayesian dynamic occurrence model with forage availability, rock size, and multiple den temperature metrics as the explanatory variables. Our top model indicated that daily maximum temperature during both summer and winter best predicted den persistence and larger rocks had a moderating effect on warm summer den temperatures. This information helps to advance understanding about the mechanistic links between climate and population persistence for small mammal species under a rapidly changing arctic climate.

Alaska↗

USGS2022

Elevating human dimensions of amphibian and reptile conservation, a USA perspective

Increasing threats to amphibian and reptile species raise the urgency of their conservation. However, relative to other vertebrate groups at risk, amphibians and reptiles have low and more variable social capital; they are not generally high-priority natural goods and services valued by people. Consequently, relative to other groups such as birds, mammals, and economically important fish, they garner fewer conservation resources. With increasing risks, their situation degrades. We examine five societal sectors with herpetofaunal conservation interests in the United States (local communities, people in defined geographies and jurisdictions, species and threat specialists and advocates, associated researchers, managers, and policy makers) to understand challenges of low and variable social capital for herpetofauna. With current trends of US public values changing from traditionalist consumerism of wildlife to mutualist coexistence philosophies, a refocus of outreach and inreach efforts could help reframe priorities toward species at greatest risk, rather than broad taxonomic biases. Integrated teams of engaged natural resource managers, researchers, and the interested public can help promote species- and issue-based programs to forestall losses, hence programmatically raising social capital. Heightened recognition of the importance of human relationships and herpetofaunal diversity among researchers, managers, policy makers, educators, artists, authors, citizens, and children could provide inertia to reframe conservation program effectiveness at local-to-national scales.

Conservation Science and Practice↗

USGS2010

Grassland birds wintering at U.S. Navy facilities in southern Texas

Grassland birds have undergone widespread decline throughout North America during the past several decades. Causes of this decline include habitat loss and fragmentation because of conversion of grasslands to cropland, afforestation in the East, brush and shrub invasion in the Southwest and western United States, and planting of exotic grass species to enhance forage production. A large number of exotic plant species, including grasses, have been introduced in North America, but most research on the effects of these invasions on birds has been limited to breeding birds, primarily those in northern latitudes. Research on the effects of exotic grasses on birds in winter has been extremely limited. This is the first study in southern Texas to examine and compare winter bird responses to native and exotic grasslands. This study was conducted during a period of six years (2003–2009) on United States Navy facilities in southern Texas including Naval Air Station–Corpus Christi, Naval Air Station–Kingsville, Naval Auxiliary Landing Field Waldron, Naval Auxiliary Landing Field Orange Grove, and Escondido Ranch, all of which contained examples of native grasslands, exotic grasslands, or both. Data from native and exotic grasslands were collected and compared for bird abundance and diversity; ground cover, vegetation density, and floristic diversity; bird and vegetation relationships; diversity of insects and arachnids; and seed abundance and diversity. Effects of management treatments in exotic grasslands were evaluated by comparing numbers and diversity of birds and small mammals in mowed, burned, and control areas. To determine bird abundance and bird species richness, birds were surveyed monthly (December–February) during the winters of 2003–2008 in transects (100 meter × 20 meter) located in native and exotic grasslands distributed at all five U.S. Navy facilities. To compare vegetation in native and exotic grasslands, vegetation characteristics were measured during 2003–2008 in the same transects used for bird surveys and included five measures of ground cover, plus estimates of plant species richness, vegetation density (visual obstruction) at two different heights, and shrub numbers. These data, plus seasonal rainfall, were then used to evaluate components of variation in native and exotic grasslands. Relations between total bird numbers and bird species richness with environmental variation in native and exotic grasslands were compared. To compare diversity of arthropods in native and exotic grasslands, insects and arachnids were collected using three different methodologies (standardized sweep-net, random sweep-net, and pitfall traps) during four seasons, (2005–2006), at Naval Air Station–Corpus Christi, Naval Auxiliary Landing Field Waldron, and Naval Air Station–Kingsville. To compare seed abundance and diversity between native and exotic grasslands, seeds were collected for two winters (2004–2006) at Naval Air Station–Corpus Christi and Naval Air Station–Kingsville. To evaluate effects of management on grassland vertebrates, abundance and diversity of birds and small mammals were estimated and compared in exotic grasses subjected to mowing, burning, or no active management (control) for one full year (2008–2009). Observations were made of 1,044 birds of 30 species in grassland transects during five winters. The Savannah Sparrow ( Passerculus sandwichensis ) was the most common bird, which, with 644 detections, accounted for 63 percent of all individuals identified to species. Meadowlarks ( Sturnella spp. ) and Le Conte’s Sparrows ( Ammodramus leconteii ) were the second (10 percent) and third (7 percent) most abundant bird species, respectively. Six of the seven most abundant species detected in grasslands were grassland species, and their numbers accounted for 87 percent of all birds, but 20 of the 30 species (67 percent) that used grasslands were not grassland species. Seven species observed in grassland transects during the study were Species of Conservation Concern: Le Conte’s Sparrow, Sedge Wren ( Cistothorus platensis ), Grasshopper Sparrow ( Ammodramus savannarum ), Long-billed Curlew ( Numenius americanus ), Sprague’s Pipit ( Anthus spragueii ), Cassin’s Sparrow ( Aimophila cassinii ), and Loggerhead Shrike ( Lanius ludovicianus ). Native grasslands consistently supported greater bird species richness than exotic grasslands. In one winter, exotic grasslands supported more birds than native grasslands. Native grasslands were determined to have more forb cover, more bare ground, and greater plant species richness than exotic grasslands, whereas exotic grasslands were characterized by more grass cover and relatively greater vegetation density during dry years. Not only did these individual measures differ between native and exotic grasslands, but components of variation also differed. In native grasslands, grass density and cover contributed more to variation, whereas in exotic grasslands, non-grass vegetation was a greater component of variation. Total bird numbers and bird species richness in native grasslands were related to the principal component that contained a measure of litter cover. Total bird numbers and bird species richness in exotic grasslands indicated no significant relationships with any of the principal components of variation. The two most common insect orders in native grasslands were Hymenoptera and Coleoptera, which accounted for 42 percent of all insects. The two most common insect orders in exotic grasslands were Hemiptera and Homoptera, which accounted for about 80 percent of all insects. Insect family richness was greater in exotic grasslands than in native grasslands in two of four seasons. Proportions of arachnid families were similar in native and exotic grasslands, but arachnid family richness was greater in exotic grasslands than in native grasslands. Abundance of seeds was greater in exotic than in native grasslands. However, seed diversity was greater in native grasslands than in exotic grasslands. Among the three types of management (mowed, burned, and control) applied to exotic grasses, birds were most abundant in the mowed area. Sedge Wrens, however, were never encountered in mowed sites. Meadowlarks were similarly abundant in all treatments, but Le Conte’s Sparrows were detected only in the control (unmanaged) area. Hispid cotton rats ( Sigmodon hispidus ) accounted for 93 percent of all rodent captures, with the number of captures peaking December through February. Hispid cotton rat numbers and total rodent numbers were greatest in control and pre-burn areas, and lowest in the mowed area. Mammal diversity, however, was greatest in the mowed habitat. Native and exotic grasslands differed essentially in all categories (bird numbers and diversity, vegetation characteristics, components of variation, diversity of insects and arachnids, and seed abundance and diversity) used to measure and compare them. This indicates that fundamental ecosystem processes have been altered after native grasslands have undergone invasion and ultimate domination by exotic grass species. Future research in Texas grassland ecosystems is essential because: 1) Texas sustains more area in grasslands than any other state or province in the Central Flyway; 2) Texas serves as the winter destination or migration pathway for hundreds of species of birds, including winter residents and Neotropical migrants; 3) ecology, distribution, and numbers of grassland birds wintering in southern latitudes of the United States remains poorly understood; and 4) climate change threatens to further accelerate advances of invading grass species.

Open-File Report↗

USGS2019

Final Report for Phase 1 - USGS-NE CSC and USFS-NRS Cooperative Research on Climate-Vulnerable Habitats and Species in the Northeast

The US Forest Service (USFS) and Northeast Climate (Adaptation) Science Center (NE CASC) came together to focus research and management cooperation on the topic of the impacts of climate change on forested ecosystems. This work had 3 primary components: 1) modeling headwater stream refugia; 2) investigating resilience and resistance strategies for New England forests; and 3) studying the impact of climate change on forest mammal communities. USFS and NE CASC organizations have complimentary expertise to share in order to improve natural resource management in the critical montane and headwater habitats in the region, and worked together to use this expertise in advancing science and science support for natural resource adaptation to a changing climate. This work resulted in increased understanding of the direct, indirect, and interactive responses of at-risk coldwater, montane and northern species to a changing climate; 2) the development of approaches and strategies for adaptation, including identification of potential climate refugia; and 3) interactive platforms for data, models and forecasts to communicate these and related results to the conservation and management community.

Connecticut, Delaware, Illinois, Indiana, Iowa, Ke↗

USGS2010

Biological pathways of exposure and ecotoxicity values for uranium and associated radionuclides: Chapter D in Hydrological, geological, and biological site characterization of breccia pipe uranium deposits in Northern Arizona

This chapter compiles available chemical and radiation toxicity information for plants and animals from the scientific literature on naturally occurring uranium and associated radionuclides. Specifically, chemical and radiation hazards associated with radionuclides in the uranium decay series including uranium, thallium, thorium, bismuth, radium, radon, protactinium, polonium, actinium, and francium were the focus of the literature compilation. In addition, exposure pathways and a food web specific to the segregation areas were developed. Major biological exposure pathways considered were ingestion, inhalation, absorption, and bioaccumulation, and biota categories included microbes, invertebrates, plants, fishes, amphibians, reptiles, birds, and mammals. These data were developed for incorporation into a risk assessment to be conducted as part of an environmental impact statement for the Bureau of Land Management, which would identify representative plants and animals and their relative sensitivities to exposure of uranium and associated radionuclides. This chapter provides pertinent information to aid in the development of such an ecological risk assessment but does not estimate or derive guidance thresholds for radionuclides associated with uranium. Previous studies have not attempted to quantify the risks to biota caused directly by the chemical or radiation releases at uranium mining sites, although some information is available for uranium mill tailings and uranium mine closure activities. Research into the biological impacts of uranium exposure is strongly biased towards human health and exposure related to enriched or depleted uranium associated with the nuclear energy industry rather than naturally occurring uranium associated with uranium mining. Nevertheless, studies have reported that uranium and other radionuclides can affect the survival, growth, and reproduction of plants and animals. Exposure to chemical and radiation hazards is influenced by a plant’s or an animal’s life history and surrounding environment. Various species of plants, invertebrates, fishes, amphibians, reptiles, birds, and mammals found in the segregation areas that are considered species of concern by State and Federal agencies were included in the development of the site-specific food web. The utilization of subterranean habitats (burrows in uranium-rich areas, burrows in waste rock piles or reclaimed mining areas, mine tunnels) in the seasonally variable but consistently hot, arid environment is of particular concern in the segregation areas. Certain species of reptiles, amphibians, birds, and mammals in the segregation areas spend significant amounts of time in burrows where they can inhale or ingest uranium and other radionuclides through digging, eating, preening, and hibernating. Herbivores may also be exposed though the ingestion of radionuclides that have been aerially deposited on vegetation. Measured tissues concentrations of uranium and other radionuclides are not available for any species of concern in the segregation areas. The sensitivity of these animals to uranium exposure is unknown based on the existing scientific literature, and species-specific uranium presumptive effects levels were only available for two endangered fish species known to inhabit the segregation areas. Overall, the chemical toxicity data available for biological receptors of concern were limited, although chemical and radiation toxicity guidance values are available from several sources. However, caution should be used when directly applying these values to northern Arizona given the unique habitat and life history strategies of biological receptors in the segregation areas and the fact that some guidance values are based on models rather than empirical (laboratory or field) data. No chemical toxicity information based on empirical data is available for reptiles, birds, or wild mammals; therefore, the risks associated with uranium and other radionuclides are unknown for these biota.

Arizona↗

USGS2017

Potential for spatial displacement of Cook Inlet beluga whales by anthropogenic noise in critical habitat

The population of beluga whales in Cook Inlet, Alaska, USA, declined by nearly half in the mid-1990s, primarily from an unsustainable harvest, and was listed as endangered in 2008. In 2014, abundance was ~340 whales, and the population trend during 1999-2014 was -1.3% yr -1 . Cook Inlet beluga whales are particularly vulnerable to anthropogenic impacts, and noise that has the potential to reduce communication and echolocation range considerably has been documented in critical habitat; thus, noise was ranked as a high potential threat in the Cook Inlet beluga Recovery Plan. The current recovery strategy includes research on effects of threats potentially limiting recovery, and thus we examined the potential impact of anthropogenic noise in critical habitat, specifically, spatial displacement. Using a subset of data on anthropogenic noise and beluga detections from a 5 yr acoustic study, we evaluated the influence of noise events on beluga occupancy probability. We used occupancy models, which account for factors that affect detection probability when estimating occupancy, the first application of these models to examine the potential impacts of anthropogenic noise on marine mammal behavior. Results were inconclusive, primarily because beluga detections were relatively infrequent. Even though noise metrics (sound pressure level and noise duration) appeared in high-ranking models as covariates for occupancy probability, the data were insufficient to indicate better predictive ability beyond those models that only included environmental covariates. Future studies that implement protocols designed specifically for beluga occupancy will be most effective for accurately estimating the effect of noise on beluga displacement.

Alaska↗

USGS2007

Overview of developmental, reproductive, and behavioral/ neurological effects of mercury exposures in wildlife

We review wildlife/mercury literature and our own research findings that demonstrate the relevance of wildlife toxicity data in protecting human health. Methylmercury affects wildlife through reduced adult survival and reproduction, aberrant behavior, immune system effects, and teratogenic effects. Methylmercury can readily cross the blood-brain barrier, is excreted into eggs in birds, and is transferred to young mammals across the placenta and in milk. Its principal effect on wildlife is on neurological functions. Wild mink (Mustela vison) and otter (Lutra canadensis) have died from methylmercury poisoning, with signs of poisoning including anorexia, loss of weight, incoordination, tremors, and convulsions, which are symptoms similar to those experienced by mercury-poisoned humans. Mammals also may experience tonic and clonic convulsions and an increase in fetal anomalies, again paralleling toxic problems in people. Antibody-producing cells can be suppressed by methylmercury. Microscopically, the most notable lesions are in the cerebrum. Extensive vacuolation of hepatocytes in the liver and necrosis and other changes in the appearance of the proximal convoluted tubules of the kidneys are often noted. When harp seals (Pagophilus groenlandicus) were dosed with methylmercury chloride the number of circulating erythrocytes decreased and white blood cell counts greatly increased. The poisoned seals also suffered from uremia, hyperproteinemia, hypercholesterolemia, hyperbilirubinemia, and elevations in lactic dehydrogenase and alkaline phosphatase. In birds, signs of methylmercury poisoning included emaciation and weakness in the extremities, which progressed until the birds died. Mercury poisoning in birds and mammals can be diagnosed from a combination of the signs of poisoning if the animal is still alive, the pathological effects seen in a gross necropsy, the histopathological effects seen with a microscope, and the concentrations of mercury in various tissues. Our studies with mallards (Anas platyrhynchos) suggest that the dietary concentrations of mercury that cause toxicity are lower than those set in fish consumption advisories to protect humans. Because wild mammals and birds are so sensitive to methylmercury poisoning and cannot escape dietary exposure the way humans can, guidelines set to protect wild birds and mammals may very well provide a margin of safety for human health.

Book chapter↗

USGS2007

Vascular Plant and Vertebrate Inventory of Organ Pipe Cactus National Monument

Executive Summary We summarized inventory and monitoring efforts for plants and vertebrates at Organ Pipe Cactus National Monument (NM) in Arizona. We used data from previous research to compile complete species lists for the monument and to assess inventory completeness. There have been 1,031 species of plants and vertebrates observed at the monument. Most of the species on the list are documented by voucher specimens. There are 59 non-native species established in the monument: one mammal, three birds, and 55 non-native plants. Most non-native plant species were first recorded along roads. In each taxon-specific chapter, we highlight areas that contribute disproportionately to species richness or that have unique species for the monument. Of particular importance are Quitobaquito Springs and Pond, which are responsible for the monument having one of the highest number of bird species in the Sonoran Desert Network of parks. Quitobaquito also contains the only fish in the monument, the endangered Quitobaquito pupfish (Cyprinodon eremus). Other important resources for the plants and vertebrates include the xeroriparian washes (e.g., Alamo Canyon) and the Ajo Mountains. Based on the review of past studies, we believe the inventories of vascular plants and vertebrates are nearly complete and that the monument has one of the most complete inventories of any unit in the Sonoran Desert Network.

Open-File Report↗

USGS2018

Surveys of environmental DNA (eDNA): a new approach to estimate occurrence in Vulnerable manatee populations

Environmental DNA (eDNA) detection is a technique used to non-invasively detect cryptic, low density, or logistically difficult-to-study species, such as imperiled manatees. For eDNA measurement, genetic material shed into the environment is concentrated from water samples and analyzed for the presence of target species. Cytochrome b quantitative PCR and droplet digital PCR eDNA assays were developed for the 3 Vulnerable manatee species: African, Amazonian, and both subspecies of the West Indian (Florida and Antillean) manatee. Environmental DNA assays can help to delineate manatee habitat ranges, high use areas, and seasonal population changes. To validate the assay, water was analyzed from Florida’s east coast containing a high-density manatee population and produced 31564 DNA molecules l -1 on average and high occurrence (ψ) and detection (p) estimates (ψ = 0.84 [0.40-0.99]; p = 0.99 [0.95-1.00]; limit of detection 3 copies µl -1 ). Similar occupancy estimates were produced in the Florida Panhandle (ψ = 0.79 [0.54-0.97]) and Cuba (ψ = 0.89 [0.54-1.00]), while occupancy estimates in Cameroon were lower (ψ = 0.49 [0.09-0.95]). The eDNA-derived detection estimates were higher than those generated using aerial survey data on the west coast of Florida and may be effective for population monitoring. Subsequent eDNA studies could be particularly useful in locations where manatees are (1) difficult to identify visually (e.g. the Amazon River and Africa), (2) are present in patchy distributions or are on the verge of extinction (e.g. Jamaica, Haiti), and (3) where repatriation efforts are proposed (e.g. Brazil, Guadeloupe). Extension of these eDNA techniques could be applied to other imperiled marine mammal populations such as African and Asian dugongs.

Endangered Species Research↗