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At least 361 records · Page 20Linked to original sources
USGS2013

Band reporting probablilities of mallards, American black ducks, and wood ducks in eastern North America

Estimates of band reporting probabilities are used for managing North American waterfowl to convert band recovery probabilities into harvest probabilities, which are used to set harvest regulations. Band reporting probability is the probability that someone who has shot and retrieved a banded bird will report the band. This probability can vary relative to a number of factors, particularly the inscription on the band and the ease with which it can be reported. Other factors, such as geographic reporting region, and species and sex of the bird may also play a role. We tested whether reporting probabilities of wood ducks ( Aix sponsa ) and American black ducks (black ducks; Anas rubripes ) differed from those of mallards ( Anas platyrhynchos ) and whether band reporting varied geographically or by the sex of the banded bird. In the analysis of spatially comparable wood duck and mallard data, a band reporting probability of 0.73 (95% CI = 0.67–0.78) was appropriate for use across species, sex, and reporting region within the United States. In the black duck–mallard comparison, the band reporting probability of black ducks in Eastern Canada (0.50, 95% CI = 0.44–0.57) was lower than in the Eastern United States (0.73, 95% CI = 0.62–0.83). These estimates reflected an increase in overall band reporting probability following the addition of a toll-free telephone number to band inscriptions. Lower reporting in Eastern Canada may be because of cultural, linguistic, or logistical barriers.

Journal of Wildlife Management↗
USGS2013

Rejuvenating Pre-GPS era geophysical surveys using The National Map

Old geophysical surveys [pre–Global Positioning System (GPS)] stand as valuable, largely untapped sources of scientific data. If data from these surveys were in a format that had reasonable accuracy, availability, and ease of access, they could be more widely used. In this paper, a pre-GPS survey is integrated into a modern geographic database, in this case, The National Map (TNM). The ultimate goal is to improve the accuracy, precision, provenance, and ease of access of the geospatial components of archived geophysical data. An unique set of data sources was assembled for this purpose. A comparison of these different data sources indicates that more than 80% of stations were positioned on The National Map within 15 m (horizontal) and 2 m (vertical) of the GPS-derived coordinates for each station within the survey. Although online database coordinate accuracy continues to improve, these results imply that web databases have already matured to a point where it is possible to integrate pre-GPS era survey coordinate data with reasonable positional accuracy.

Missouri↗
USGS2016

Elevational speciation in action? Restricted gene flow associated with adaptive divergence across an altitudinal gradient

Evolutionary theory predicts that divergent selection pressures across elevational gradients could cause adaptive divergence and reproductive isolation in the process of ecological speciation. Although there is substantial evidence for adaptive divergence across elevation, there is less evidence that this restricts gene flow. Previous work in the boreal chorus frog (Pseudacris maculata) has demonstrated adaptive divergence in morphological, life history and physiological traits across an elevational gradient from approximately 1500–3000 m in the Colorado Front Range, USA. We tested whether this adaptive divergence is associated with restricted gene flow across elevation – as would be expected if incipient speciation were occurring – and, if so, whether behavioural isolation contributes to reproductive isolation. Our analysis of 12 microsatellite loci in 797 frogs from 53 populations revealed restricted gene flow across elevation, even after controlling for geographic distance and topography. Calls also varied significantly across elevation in dominant frequency, pulse number and pulse duration, which was partly, but not entirely, due to variation in body size and temperature across elevation. However, call variation did not result in strong behavioural isolation: in phonotaxis experiments, low-elevation females tended to prefer an average low-elevation call over a high-elevation call, and vice versa for high-elevation females, but this trend was not statistically significant. In summary, our results show that adaptive divergence across elevation restricts gene flow in P. maculata, but the mechanisms for this potential incipient speciation remain open.

Colorado↗
USGS2018

Optimal treatment allocations in space and time for online control of anemerging infectious disease

A key component in controlling the spread of an epidemic is deciding where, when and to whom to apply an intervention. We develop a framework for using data to inform these decisions in realtime. We formalize a treatment allocation strategy as a sequence of functions, one per treatment period, that map up‐to‐date information on the spread of an infectious disease to a subset of locations where treatment should be allocated. An optimal allocation strategy optimizes some cumulative outcome, e.g. the number of uninfected locations, the geographic footprint of the disease or the cost of the epidemic. Estimation of an optimal allocation strategy for an emerging infectious disease is challenging because spatial proximity induces interference between locations, the number of possible allocations is exponential in the number of locations, and because disease dynamics and intervention effectiveness are unknown at outbreak. We derive a Bayesian on‐line estimator of the optimal allocation strategy that combines simulation–optimization with Thompson sampling. The estimator proposed performs favourably in simulation experiments. This work is motivated by and illustrated using data on the spread of white nose syndrome, which is a highly fatal infectious disease devastating bat populations in North America.

Journal of the Royal Statistical Society. Series C↗
USGS2014

Multilocus phylogeography and systematic revision of North American water shrews (genus: Sorex )

North American water shrews, which have traditionally included Sorex alaskanus , S. bendirii , and S. palustris , are widely distributed through Nearctic boreal forests and adapted for life in semiaquatic environments. Molecular mitochondrial signatures for these species have recorded an evolutionary history with variable levels of regional divergence, suggesting a strong role of Quaternary environmental change in speciation processes. We expanded molecular analyses, including more-comprehensive rangewide sampling of specimens representing North American water shrew taxa, except S. alaskanus , and sequencing of 4 independent loci from the nuclear and mitochondrial genomes. We investigated relative divergence of insular populations along the North Pacific Coast, and newly recognized diversity from southwestern montane locations, potentially representing refugial isolates. Congruent independent genealogies, lack of definitive evidence for contemporary gene flow, and high support from coalescent species trees indicated differentiation of 4 major geographic lineages over multiple glacial cycles of the late Quaternary, similar to a growing number of boreal taxa. Limited divergence of insular populations suggested colonization following the last glacial. Characterization of southwestern montane diversity will require further sampling but divergence over multiple loci is indicative of a relictual sky-island fauna. We have reviewed and revised North American water shrew taxonomy including the recognition of 3 species within what was previously known as S. palustris . The possibility of gene flow between most distantly related North American water shrew lineages coupled with unresolved early diversification of this group and other sibling species reflects a complex but potentially productive system for investigating speciation processes.

Journal of Mammalogy↗
USGS1993

Multivariate model of female black bear habitat use for a Geographic Information System

Simple univariate statistical techniques may not adequately assess the multidimensional nature of habitats used by wildlife. Thus, we developed a multivariate method to model habitat-use potential using a set of female black bear ( Ursus americanus ) radio locations and habitat data consisting of forest cover type, elevation, slope, aspect, distance to roads, distance to streams, and forest cover type diversity score in the Ozark Mountains of Arkansas. The model is based on the Mahalanobis distance statistic coupled with Geographic Information System (GIS) technology. That statistic is a measure of dissimilarity and represents a standardized squared distance between a set of sample variates and an ideal based on the mean of variates associated with animal observations. Calculations were made with the GIS to produce a map containing Mahalanobis distance values within each cell on a 60- × 60-m grid. The model identified areas of high habitat use potential that could not otherwise be identified by independent perusal of any single map layer. This technique avoids many pitfalls that commonly affect typical multivariate analyses of habitat use and is a useful tool for habitat manipulation or mitigation to favor terrestrial vertebrates that use habitats on a landscape scale.

Arkansas↗
USGS2001

Comparing movement patterns of satellite-tagged male and female polar bears

Satellite radiotelemetry has provided great insights into the movements and behaviors of polar bears ( Ursus maritimus ). The diameter of the neck of adult male polar bears exceeds that of their head, however, and radio collars slip off. This has limited collection of movement information to that from radio-collared females. To overcome this difficulty and gather information about their movements, we surgically implanted satellite radio transmitters into 7 male polar bears during 1996 and 1997. We compared movements of implanted males with those of 104 adult females radio-collared between 1985 and 1995. Transmitters were implanted under the skin on the midline of the top of the neck and were equipped with percutaneous antennae. Implanted transmitters operated for up to 161 days providing 3217 satellite relocations. While transmitting, radios implanted in males provided a larger proportion of the highest quality category of position fixes than was obtained from radio-collared females. However, all implanted radios ceased transmitting before reaching their projected life-span. The abrupt termination of transmission from implanted radios suggested mechanical rather than electronic failure. Mean rates of short-term movement for males (1.18 km/h) were lower than for solitary females, females with cubs, and females with yearlings (1.70, 1.84, and 1.95 km/h, respectively). Net geographic movements from the beginning to the end of each month were comparable for males (mean = 135 km) and females (mean = 114, 152, and 168 km). Mean azimuths of these net movements also appeared to be similar. Monthly activity-area sizes for males (mean = 8541 km 2 ) were comparable to those for females (mean = 3698, 9397, and 10 585 km 2 ) during the time period of comparison. In contrast to the other movement measures, males traveled longer mean distances (387 km) each month than did females (217, 289, and 302 km). Movements of males, it appears, were more directed than those of females, but males confined their travels to similar-sized areas.

Alaska, Northwest Territories↗
USGS2001

Space-time modelling of lightning-caused ignitions in the Blue Mountains, Oregon

Generalized linear mixed models (GLMM) were used to study the effect of vegetation cover, elevation, slope, and precipitation on the probability of ignition in the Blue Mountains, Oregon, and to estimate the probability of ignition occurrence at different locations in space and in time. Data on starting location of lightning-caused ignitions in the Blue Mountains between April 1986 and September 1993 constituted the base for the analysis. The study area was divided into a pixela??time array. For each pixela??time location we associated a value of 1 if at least one ignition occurred and 0 otherwise. Covariate information for each pixel was obtained using a geographic information system. The GLMMs were fitted in a Bayesian framework. Higher ignition probabilities were associated with the following cover types: subalpine herbaceous, alpine tundra, lodgepole pine (Pinus contorta Dougl. ex Loud.), whitebark pine (Pinus albicaulis Engelm.), Engelmann spruce (Picea engelmannii Parry ex Engelm.), subalpine fir (Abies lasiocarpa (Hook.) Nutt.), and grand fir (Abies grandis (Dougl.) Lindl.). Within each vegetation type, higher ignition probabilities occurred at lower elevations. Additionally, ignition probabilities are lower in the northern and southern extremes of the Blue Mountains. The GLMM procedure used here is suitable for analysing ignition occurrence in other forested regions where probabilities of ignition are highly variable because of a spatially complex biophysical environment.

Canadian Journal of Forest Research↗
USGS1982

Measurements of fall migrant peregrine falcons from Texas and New Jersey

Three subspecies of Peregrine Falcons (Falco peregrinus) breed in North America: F. p. anatum, formerly bred in all eco-geographic regions of North America south of the Arctic tundra, except for the immediate vicinity of the northwest Pacific Coast; F. p. tundrius breeds in the Arctic tundra; and F. p. pealei, a relatively sedentary form, occupies the region of the northwest Pacific coast excluded from the range of F. p. anatum (Fyfe et al. 1976). Compared with tundrius, anatum is larger and darker, and the white auricular area is less extensive in proportion to the black malar stripe (White 1968a). This paper presents morphological information from two migrant populations. Also, measurements are compared with F. p. tundrius described by White (1968a,b), although shrinkage in study skins (the source of White's measurements) was recently documented (Fjelds• 1980) and confounds direct comparison.

Texas, New Jersey↗
USGS2015

Density, distribution, and genetic structure of grizzly bears in the Cabinet-Yaak Ecosystem

The conservation status of the 2 threatened grizzly bear ( Ursus arctos ) populations in the Cabinet-Yaak Ecosystem (CYE) of northern Montana and Idaho had remained unchanged since designation in 1975; however, the current demographic status of these populations was uncertain. No rigorous data on population density and distribution or analysis of recent population genetic structure were available to measure the effectiveness of conservation efforts. We used genetic detection data from hair corral, bear rub, and opportunistic sampling in traditional and spatial capture–recapture models to generate estimates of abundance and density of grizzly bears in the CYE. We calculated mean bear residency on our sampling grid from telemetry data using Huggins and Pledger models to estimate the average number of bears present and to correct our superpopulation estimates for lack of geographic closure. Estimated grizzly bear abundance (all sex and age classes) in the CYE in 2012 was 48–50 bears, approximately half the population recovery goal. Grizzly bear density in the CYE (4.3–4.5 grizzly bears/1,000 km 2 ) was among the lowest of interior North American populations. The sizes of the Cabinet ( n = 22–24) and Yaak ( n = 18–22) populations were similar. Spatial models produced similar estimates of abundance and density with comparable precision without requiring radio-telemetry data to address assumptions of geographic closure. The 2 populations in the CYE were demographically and reproductively isolated from each other and the Cabinet population was highly inbred. With parentage analysis, we documented natural migrants to the Cabinet and Yaak populations by bears born to parents in the Selkirk and Northern Continental Divide populations. These events supported data from other sources suggesting that the expansion of neighboring populations may eventually help sustain the CYE populations. However, the small size, isolation, and inbreeding documented by this study demonstrate the need for comprehensive management designed to support CYE population growth and increased connectivity and gene flow with other populations.

Idaho, Montana↗
USGS2020

Climate change vulnerability assessment for Pacific Lamprey in rivers of the Western United States

Pacific Lamprey (Entosphenus tridentatus) are a native anadromous species that, like salmon, historically returned to spawn in large numbers in watersheds along the west coast of the United States (U.S.). Lamprey play a vital role in river ecosystems and are one of the oldest vertebrates that have persisted over time likely influencing the evolution of many aquatic species. Pacific Lamprey have declined in abundance and are restricted in distribution throughout Washington, Oregon, Idaho and California. A key uncertainty influencing Pacific Lamprey status is the impact of climate change. We modified the NatureServe Climate Change Vulnerability Index (CCVI) to accommodate climate predictions from the International Panel on Climate Change. Using downscaled information, we characterized changes in 15 rivers occupied by Pacific Lamprey in the western U.S. We evaluated this risk under Representative Concentration Pathways (RCP) 4.5 and 8.5 for two time periods (mid-century 2040–2069 and end-century 2070–2099). The CCVI scores generally increased when going from RCP 4.5 to RCP 8.5 in three Global Climate Models for both mid-century and end-century, which our analyses forecasts degraded stream temperature and hydrologic conditions under increasing greenhouse gas emissions. The geographically assessed results suggest that climate change impacts to Pacific Lamprey vulnerability are magnified in highly altered rivers. If we continue to observe greenhouse gas emission levels associated with the RCP 8.5, Pacific Lamprey will be at greater risk to climate change impacts. In order to mitigate the risk from climate change toward the end of the century, additional actions will need to be prioritized to rapidly reduce the impact of these threats such as increasing flow, creating backwater habitat, restoring riparian vegetation and reducing stream disturbances. The findings revealed the patterns of vulnerability for Pacific Lamprey across their U.S. range are informative for prioritizing river restoration actions when paired with regional implementation plans.

California, Washington, Oregon, Idaho↗
USGS2014

Sex-biased gene flow among elk in the greater Yellowstone ecosystem

We quantified patterns of population genetic structure to help understand gene flow among elk populations across the Greater Yellowstone Ecosystem. We sequenced 596 base pairs of the mitochondrial control region of 380 elk from eight populations. Analysis revealed high mitochondrial DNA variation within populations, averaging 13.0 haplotypes with high mean gene diversity (0.85). The genetic differentiation among populations for mitochondrial DNA was relatively high ( F ST = 0.161; P = 0.001) compared to genetic differentiation for nuclear microsatellite data ( F ST = 0.002; P = 0.332), which suggested relatively low female gene flow among populations. The estimated ratio of male to female gene flow ( m m / m f = 46) was among the highest we have seen reported for large mammals. Genetic distance (for mitochondrial DNA pairwise F ST ) was not significantly correlated with geographic (Euclidean) distance between populations (Mantel's r = 0.274, P = 0.168). Large mitochondrial DNA genetic distances (e.g., F ST > 0.2) between some of the geographically closest populations (<65 km) suggested behavioral factors and/or landscape features might shape female gene flow patterns. Given the strong sex-biased gene flow, future research and conservation efforts should consider the sexes separately when modeling corridors of gene flow or predicting spread of maternally transmitted diseases. The growing availability of genetic data to compare male vs. female gene flow provides many exciting opportunities to explore the magnitude, causes, and implications of sex-biased gene flow likely to occur in many species.

Yellowstone National Park↗
USGS2004

Assessing biodiversity in Nuevo Leon, Mexico: Are nature reserves the answer?

The Mexican state of Nuevo Leon, located in the northeastern portion of the country, currently has 26 state and three federal nature reserves covering approximately 4.5% of its land area. These reserves were established for a variety of reasons not necessarily related to conservation purposes. In 2000 in response to a growing concern about the lack of organized conservation reserve planning to protect the important biological and physical features of Mexico, the Mexican Commission for Knowledge and Use of Biodiversity proposed 12 new terrestrial reserves for Nuevo Leon. The new reserves, if established, would increase the proportion of protected lands in the state to almost 24% of the state's land area. We compiled a Geographic Information System (GIS) analysis using digital thematic maps of physical and ecological features to examine how well the existing and proposed reserves incorporated the major biological and physical features of the state. The existing reserves are located primarily in regions with elevations > 1,000-1,500 m, on less productive soils, and are dominated by pine and oak forest cover types. As a result, the state's dominant biotic region - low elevation coastal plain with xeric scrub vegetation - is disproportionately under represented in the current reserve system. The new reserves would expand the protection of biophysical resources throughout the state. However, the inclusion of important resources in the low elevation coastal lands would still be limited.

Nuevo Leon↗
USGS2020

Latitudinal variation in snowshoe hare (Lepus americanus) body mass: A test of Bergmann’s Rule

The relationship between body size and latitude have been the focus of dozens of studies across many species. However, results of testing Bergmann’s Rule – that organisms in colder climates or at higher latitudes possess larger body sizes – have been inconsistent across studies. We investigated whether snowshoe hares (Lepus americanus) follow the Rule by investigating differences in body mass using data from six published studies and from data of 755 individual hares captured from ten populations across North America covering 26° of latitude. We also explored alternative hypotheses related to variation in hare body mass, including winter severity, length of growing season, elevation, and snow depth. We found body mass of hares varied throughout their range, but the drivers of body mass differed based on geographic location. Females in northern populations followed Bergmann’s rule, whereas males did not. In northern populations male mass was related to average snow depth. In contrast, in southern populations body mass of both sexes was related to length of the growing season. These differences likely represent variation in the drivers of selection. Specifically, in the north, a large body size is beneficial to conserve heat because of low winter temperatures, whereas in the south, it is likely due to increased food supply associated with longer growing seasons.

Canadian Journal of Zoology↗
USGS2023

Geographic distribution of the Puerto Rican Harlequin Butterfly (Atlantea tulita): An ensemble modeling approach

Species distribution models have become increasingly important tools for species conservation. This modeling approach can help guide conservation practitioners and inform decisions. Distribution models are particularly relevant for rare species, whose habitat associations are often not well understood. Using species occurrence data, and a variety of predictor variables, we developed three individual distribution models and a weighted ensemble model for the Puerto Rican harlequin butterfly ( Atlantea tulita ). The ensemble model had the greatest accuracy (AUC = 0.92). Further, the ensemble model indicated 7.1% of the main island of Puerto Rico encompassed suitable habitat for the harlequin butterfly. However, only 0.5% was classified as including the greatest suitability. Using an ensemble modeling approach to delineate areas of the island with suitable environmental conditions may improve habitat conservation efforts for the species.

Caribbean Journal of Science↗
USGS2025

Predicting niche spaces of expanding Evening Bat (Nycticeius humeralis) populations following white-nose syndrome establishment

Observations of the Evening Bat ( Nycticeius humeralis ), a species historically distributed abundantly throughout the southeastern United States, are speculated to have increased in the Midwest. One hypothesis for this expansion in geographic distribution is that local extirpations of other bat species resulted in the expanded realized niche spaces for evening bats. In Indiana, such niche spaces may have been created by declines in populations of the Northern Long-eared Bat ( Myotis septentrionalis ), Indiana Bat ( M. sodalis ), Little Brown Bat ( M. lucifugus ), Big Brown Bat ( Eptesicus fuscus ), and the Tri-colored Bat ( Perimyotis subflavus ) due to white-nose syndrome (WNS). Our goal was to estimate the occupancy of Evening Bat in Indiana post-WNS establishment relative to the occupancy of other bat species before significant population declines caused by WNS. We expected that indices of occupancy of nearly extirpated species pre-WNS establishment would best predict current Evening Bat observations, and this would elucidate the niche space evening bats are now filling. We hypothesized that Evening Bat populations may be expanding their geographic range due to compensatory community dynamics, and that their realized niche space may be expanding in part due to losses of other bat species from WNS. We constructed multi-season Bayesian occupancy models using informative priors and integrative prior knowledge to test our predictions. We found that evening bats are occupying the niche space they were already occupying pre-WNS establishment. Furthermore, our results indicate that evening bats may be filling the niche space left behind by Myotis spp. ( M. sodalis and M. lucifigus ). These results can help us understand the dynamics of bat communities in a post-WNS establishment landscape and may also help to inform conservation of imperiled Myotis species.

Journal of Mammalogy↗
USGS1997

New records with examples of potential host colonization events for hypopi (Acari: Hypoderatidae) from birds

New host, geographic records, or both are established for 14 species of hypoderatid deutonymphs from 14 species of birds in North America. Ten of these records are regarded as examples of a potential host colonization event where these hypopi have become established in hosts other than those with which they are normally associated. Herein, potential host colonization events by hypoderatid deutonymphs are regarded as more of an ecologically determined than physiologically specific phenomenon, often specifically related to sharing of nesting sites in the same rookeries by different host taxa. Neottialges ibisicola Young & Pence is placed as a junior synonym of Neottialges plegadicola Fain. The taxonomic status of Hypodectes propus from columbid versus ardeid hosts needs further study.

Journal of Medical Entomology↗
USGS2009

Life history and status of shortnose sturgeon (Acipenser brevirostrum) in the Potomac River

We collected the first life history information on shortnose sturgeon (Acipenser brevirostrum) in any of the rivers to Chesapeake Bay, the geographic center of the species range. In the Potomac River, two telemetry-tagged adult females used 124 km of river: a saltwater/freshwater reach at river km (rkm) 63-141 was the foraging-wintering concentration area, and one female migrated to spawn at rkm 187 in Washington, DC. The spawning migration explained the life history context of an adult captured 122 years ago in Washington, DC, supporting the idea that a natal population once lived in the river. Repeated homing migrations to foraging and wintering areas suggested the adults were residents, not transient coastal migrants. All habitats that adults need to complete life history are present in the river. The Potomac River shortnose sturgeon offers a rare opportunity to learn about the natural rebuilding of a sturgeon population.

Journal of Applied Ichthyology↗