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At least 289 records · Page 16Linked to original sources

USGS2009

Spatial habitat use patterns of sea otters in coastal washington

Sea otter (Enhydra lutris kenyoni) movements, home range, and activity budgets were described from data collected during very-high-frequency radiotelemetry studies of 75 individuals on the outer coast of Washington State between 1992 and 1999. Sea otters were located at least once per week from 22 accessible sites along the coast. Over the 7-year study period, range expansion occurred from the core range north and east into the Strait of Juan de Fuca (SJF) as well as southward on the outer coast. Forty-three percent of the sea otters moved into the SJF at least once, most often in winter, using habitat that had not been occupied by sea otters since their extirpation 100 years ago. All sea otters spent portions of their time in the vicinity of Cape Alava, and many animals demonstrated consistent periodic seasonal shifts between specific portions of the coastline over several years. Ninety-five percent annual linear home ranges differed between sex and age classes. Adult males used the largest amount of coastline (50 km ?? 9 5D) and subadult females used the least (24 ?? 9 km). Both adult males and females demonstrated high seasonal periodicity in range use in summer and winter. Twenty-four-hour time budgets in the core portion of the range revealed on average sea otters spent 41% ?? 14% SD of the time foraging and 45% ?? 13% of the time resting (age and sex classes pooled). Adult and subadult female sea otters were most frequently found resting and foraging close to shore (< 1,000 m) and in shallow water (0-10 m), whereas adult and subadult males rested and foraged > 1,000 m offshore and at depths between 10 and 30 m. Given current rates of population growth and observed mobility, sea otters in Washington have high potential for range expansion into unoccupied habitat such as Grays Harbor, Willapa Bay, the SJF, or along Vancouver Island. ?? 2009 American Society of Mammalogists.

Journal of Mammalogy↗

USGS2002

Assessing avian richness in remnant wetlands: Towards an improved methodology

Because the North American Breeding Bird Survey provides inadequate coverage of wetland habitat, the Wetland Breeding Bird Survey was recently established in Ohio, USA. This program relies on volunteers to conduct 3 counts at each monitored wetland. Currently, all counts are conducted during the morning. Under the premise that volunteer participation could be increased by allowing evening counts, we evaluated the potential for modifying the methodology. We evaluated the sampling efficiency of all 3-count combinations of morning and evening counts using data collected at 14 wetlands. Estimates of overall species richness decreased with increasing numbers of evening counts. However, this pattern did not hold when analyses were restricted to wetland-dependent species or those of conservation concern. Our findings suggest that it would be reasonable to permit evening counts, particularly if the data are to be used to monitor wetland dependent species and those of concern.

Wetlands↗

USGS2012

Characterizing seasonal and diel vertical movement and habitat use of lake whitefish (Coregonus clupeaformis) in Clear Lake, Maine

Seasonal and daily vertical activity of lake whitefish Coregonus clupeaformis was studied in Clear Lake, Maine (253 ha), using acoustic telemetry from November 2004 to June 2009. Twenty adult lake whitefish were tagged with acoustic tags that had either a depth sensor or both depth and temperature sensors to assess vertical habitat use at a seasonal and daily resolution. Vertical habitat selection varied seasonally and was strongly influenced by temperature. Between December and April, when the lake was covered with ice, surface temperature was below 2°C and tagged individuals occupied deep areas of the lake (&sim;15 m). After ice-out, fish ascended into shallow waters (&sim;5 m), responding to increased water temperature and possibly to greater foraging opportunity. When surface water temperatures exceeded 20°C, fish descended below the developing thermocline (&sim;9 m), where they remained until surface temperatures fell below 20°C; fish then ascended into shallower depths, presumably for feeding and spawning. Through the winter, fish remained in thermal habitats that were warmer than the surface temperatures; in the summer, they selected depths with thermal habitats below 15°C. Though the amplitude varied greatly across seasons, lake whitefish displayed a strong diurnal pattern of activity as measured by vertical velocities. Fish were twofold more active during spring, summer, and fall than during winter. Lake whitefish exhibited diel vertical migrations, rising in the water column during nighttime and occupying deeper waters during the day. This pattern was more pronounced in the spring and fall and far less prominent during winter and summer. The strong linkage between temperature and habitat use may limit the current range of lake whitefish and may be directly impacted by climatic change.

Main↗

USGS2020

Application of a new species-richness based flow ecology framework for assessing flow reduction effects on aquatic communities

Water‐resources managers are challenged with maintaining a balance among beneficial uses throughout river networks and need robust means of assessing potential risks to aquatic life resulting from flow alterations. This study generated ecological limit functions from species‐streamflow relations to quantify potential fish richness response to flow alteration and compared results to currently accepted streamflow management guidelines. Modeled responses of absolute richness change were watershed specific and varied among sample sets derived from hydrologic unit classifications of different sizes (large HUC 6 basins to regional scale HUC 8). With a 20% flow reduction, 10% of HUC 8 predicted a richness decrease in one or more taxa. While absolute richness change was consistent across streams within a HUC, percent richness change was stream size dependent. Comparisons with Instream Flow Incremental Methodology habitat models predicted habitat loss greater than percent richness change; however, predictions for habitat and richness decreased similarly as stream size decreased. Watershed‐specific responses from flow reductions could allow water‐resources management decisions to be made locally based on the predicted richness change for certain sized streams. Quantitative results highlight the utility of a richness‐based framework for generating watershed‐specific risk assessments that validate and inform currently employed water‐resources management practices.

Virginia↗

USGS2003

Differences in habitat use by blanding's turtles, Emydoidea blandingii, and painted turtles, Chysemys picta, in the Nebraska sandhills

We sampled a variety of wetlands in the Nebraska sandhills at Valentine National Wildlife Refuge. Significantly more individuals of painted turtles ( Chrysemys picta ) occurred in lakes and open waters than in marshes or small ponds, and the opposite was true for Blanding's turtles ( Emydoidea blandingii ). Besides this marked difference in habitat use, 46% of the captured E. blandingii in pond/marsh habitat were juveniles, but only 31.6% in lakes and open water. Current information suggests that marshes and small ponds are important habitat for juvenile turtles, especially Emydoidea blandingii .

Nebraska↗

USGS1987

Regeneration patterns of northern white cedar, an old-growth forest dominant

Regeneration of Thuja occidentalis L. was examined in an old-growth dune forest on South Manitou Island, Michigan. To estimate the current status of cedar regeneration, we determined size structure of seedlings and stems and analyzed present patterns of establishment and persistence relative to substrate type. There has been a shift in the pattern of cedar establishment from soil to log substrates. While 97% of all stems ≥15 cm dbh are associated with a soil substrate, 81% of stems ≥2.5cm-<15 cm dbh, and 98% of all cedar seedlings are confined to log substrates. However, few cedar seedlings survive; only 1% of all seedlings on logs are >25 cm tall. There was no significant relationship between the state of log decay and the density of seedlings >25 cm in height, indicating that long-term survival is not dependent on the degree of log decomposition. However, survival on logs is associated with canopy openings. Seedlings >25 cm tall were associated with gaps, and 78% of cedar stems (≥2.5 cm dbh) on logs were associated with a single windthrow gap. Thus, current cedar regeneration in this old-growth forest depends on logs and the canopy openings associated with them.

American Midland Naturalist↗

USGS2014

Mineral evolution and Earth history

The field of mineral evolution—a merger of mineralogy and Earth history—coalesced in 2008 with the first of several global syntheses by Robert Hazen and coworkers in the American Mineralogist. They showed that the cumulative abundance of mineral species has a stepwise trend with first appearances tied to various transitions in Earth history such as the end of planetary accretion at ca. 4.55 Ga and the onset of bio-mediated mineralogy at ca. >2.5 Ga. A global age distribution is best established for zircon. Observed abundance of zircon fluctuates through more than an order of magnitude during successive supercontinent cycles. The pulse of the Earth is also recorded, albeit imperfectly, by the 87 Sr/ 86 Sr composition of marine biogenic calcite; the Sr-isotopic ratio of this mineral reflects the balance of inputs of primitive strontium at mid-ocean ridges and evolved strontium that drains off the continents. A global mineral evolution database, currently in the works, will greatly facilitate the compilation and analysis of extant data and the expansion of research in mineralogy outside its traditional bounds and into more interdisciplinary realms.

American Mineralogist↗

USGS2006

CO2 and CH4 exchanges between land ecosystems and the atmosphere in northern high latitudes over the 21st century

Terrestrial ecosystems of the northern high latitudes (above 50??N) exchange large amounts of CO2 and CH4 with the atmosphere each year. Here we use a process-based model to estimate the budget of CO 2 and CH4 of the region for current climate conditions and for future scenarios by considering effects of permafrost dynamics, CO 2 fertilization of photosynthesis and fire. We find that currently the region is a net source of carbon to the atmosphere at 276 Tg C yr -1. We project that throughout the 21st century, the region will most likely continue as a net source of carbon and the source will increase by up to 473 Tg C yr-1 by the end of the century compared to the current emissions. However our coupled carbon and climate model simulations show that these emissions will exert relatively small radiative forcing on global climate system compared to large amounts of anthropogenic emissions. Copyright 2006 by the American Geophysical Union.

Geophysical Research Letters↗

USGS2014

Spatial mapping and attribution of Wyoming wind turbines, 2012

These data represent locations of wind turbines found within Wyoming as of August 2012. We assigned each wind turbine to a wind farm and, in these data, provide information about each turbine’s potential megawatt output, rotor diameter, hub height, rotor height, the status of the land ownership where the turbine exists, the county each turbine is located in, wind farm power capacity, the number of units currently associated with each wind farm, the wind turbine manufacturer and model, the wind farm developer, the owner of the wind farm, the current purchaser of power from the wind farm, the year the wind farm went online, and the status of its operation. Some of the attributes are estimates based on the information we found via the American Wind Energy Association and other on-line reports. The locations are derived from National Agriculture Imagery Program (2009 and 2012) true color aerial photographs and have a positional accuracy of approximately +/-5 meters. These data will provide a planning tool for wildlife- and habitat-related projects underway at the U.S. Geological Survey’s Fort Collins Science Center and other government and non-government organizations. Specifically, we will use these data to support quantifying disturbances of the landscape as related to wind energy as well as to quantify indirect disturbances to flora and fauna. This data set represents an update to a previous version by O’Donnell and Fancher (2010).

Wyoming↗

USGS1999

Euthanasia

Euthanasia means to cause humane death. Some current euthanasia techniques may become unacceptable over time and be replaced by new techniques as more data are gathered and evaluated. The following information and recommendations are based largely on the 1993 report of the American Veterinary Medical Association (AVMA) Panel on Euthanasia. The recommendations in the panel report were intended to serve as guidelines, and they require the use of professional judgement for specific situations. Ultimately, it is the responsibility of those persons carrying out euthanasia to assure that it is done in the most humane manner possible.

Information and Technology Report↗

USGS1994

Avian assemblages on altered grasslands

Grasslands comprise 17% of the North American landscape but provide primary habitat for only 5% of native bird species. On the Great Plains, grasslands include an eastern component of tall grasses and a western component of short grasses, both of which have been regionally altered by removing native grazers, plowing sod, draining wetlands, and encouraging woody vegetation. As a group, populations of endemic bird species of the grasslands have declined more than others (including neotropical migrants) in the last quarter century. Individually, populations of the Upland Sandpiper and McCown’s Longspur have increased; the wetlands-associated Marbled Godwit and Wilson’s Phalarope appear stable; breeding ranges are shifting for the Ferruginous Hawk, Mississippi Kite, Short-eared Owl, Upland Sandpiper, Horned Lark, Vesper, Savannah, and Henslow’s sparrows, and Western Meadowlark; breeding habitats are disappearing locally for Franklin’s Gull, Dickcissel, Henslow’s and Grasshopper sparrows. Lark Bunting, and Eastern Meadowlark; and populations are declining throughout the breeding ranges for Mountain Plover, and Cassin’s and Clay-colored sparrows. Declines of these latter three species, and also the Franklin’s Gull, presumably are due to ecological phenomena on their respective wintering areas. Unlike forest species that winter in the neotropics, most birds that breed in the North American grasslands also winter on the continent and problems driving declines in grassland species are associated almost entirely with North American processes. Contemporary programs and initiatives hold promise for the conservation of breeding habitats for these birds. Ecological ignorance of wintering habits and habitats clouds the future of the endemic birds of grasslands, especially those currently experiencing widespread declines across breeding locales.

Studies in Avian Biology↗

USGS2001

Mitochondrial phylogeography, subspecific taxonomy, and conservation genetics of sandhill cranes (Grus canadensis; Aves: Gruidae)

Six subspecies of sandhill cranes (Grus canadensis) have been denoted based on perceived morphological and/or breeding locality differences among them. Three subspecies are migratory, breeding from the high arctic in North America and Siberia (lesser sandhill, G. c. canadensis), south through central Canada (Canadian sandhill, G. c. rowani) and into the northern United States (greater sandhill, G. c. tabida). A review of sandhill crane taxonomy indicates that the size variation, on the basis of which these subspecies were named, may be clinal and not diagnostic. The other three subspecies, all listed as endangered or threatened, are non-migratory, resident in Florida (G. c. pratensis), Mississippi (G. c. pulla), and Cuba (G. c. nesiotes). We used analysis of mitochondrial DNA control region (CR) sequences to determine whether haplotypes representing current subspecies show any genetic cohesion or are more consistent with a pattern of clinal variation in morphology. CR sequences indicate that only two highly divergent (5.3%) lineages of sandhill cranes occur in North America: one lineage composed only of arctic-nesting G. c. canadensis, the other of the remaining North American subspecies (we lack data on the Cuban population). The deep split between lineages is consistent with an estimated isolation of approximately 1.5 Mya (mid-Pleistocene), while the distribution of mutational changes within lineages is consistent with an hypothesis of rapid, post-Pleistocene population expansions. No other phylogeographic structuring is concordant with subspecific boundaries, however, analysis of molecular variance indicates that there is significant population genetic differentiation among all subspecies except G. c. tabida and G. c. rowani, which are indistinguishable. We suggest that recognition of the recently named G. c. rowani be abandoned.

Conservation Genetics↗

USGS2015

Book review: Biology and conservation of North American tortoises

The charismatic North American tortoises hold a special place in our culture and natural history. Despite the perseverance of these tortoises over millions of years, biologists now question their ability to persist into the future. In light of documented declines, habitat loss, and numerous threats to tortoise populations, the editors gathered a diverse group of researchers to review what we have learned about this group after decades of study, to summarize gaps in the literature, and to reflect on how we may use the current state of knowledge to conserve these fascinating species. Initially intended as a focused review of the two most well-studied species in the genus Gopherus , G. agassizii (Mohave Desert Tortoise) and G. polyphemus (Gopher Tortoise), the book developed into a comprehensive treatment of the entire genus. The editors offer the work as a resource to professional biologists and agencies working with North American tortoises as well as a teaching aid, hobbyist’s reference, and casual read for nature-lovers—although we presume that the former group is more likely to benefit than the latter. Although the book’s size appears modest, the content delivers an in-depth look at the five recognized tortoise species. Review info: Biology and Conservation of North American Tortoises. Edited by David C. Rostal, Earl D. McCoy, and Henry R. Mushinsky, 2014. ISBN 978-1421413778, 190 pp.

Herpetological Review↗

USGS2012

Paleomagnetic study of the Eastern Klamath terrane, California, and implications for the tectonic history of the Klamath Mountains Province

Paleomagnetic study of Permian through Jurassic volcanic and sedimentary strata of the Eastern Klamath terrane has shown the remanent magnetization of many of these rocks to be prefolding and most likely primary. Similarities in magnetic declinations recorded by coeval strata over a broad area are consistent with the hypothesis that the terrane, in general, has behaved as a single rigid block. Paleomagnetic data indicate that the volcanic island arc represented by this terrane, the nucleus of the province, was facing toward the present southwest during late Paleozoic time, although its orientation during earlier periods is unknown. Whether the arc was separated from the North American craton by a small marginal basin or originated far offshore cannot be determined from paleomagnetic data. The declination anomalies for both Permian and Triassic strata are similar (average = 106° ± 12°), so we infer that clockwise rotation of the late Paleozoic arc did not begin until latest Triassic or earliest Jurassic time. The arc may have completed its initial rotation with respect to stable North America by Middle Jurassic time. After some retrograde motion, the arc was again facing west by the Late Jurassic, by which time some of the more westerly terranes of the province had become attached to the Eastern Klamath terrane. The composite Klamath Mountains terranes continued to rotate until the final 60° of clockwise rotation was nearly complete by the Early Cretaceous. Coincidence of the waning stages of rotation, at about 136 Ma, with the beginning of deposition of the basal Great Valley sequence onto the Klamath basement probably represents the completion of accretion of the Klamath Mountains terranes to the North American continent. Nearly all the rotation occurred while the Klamath Mountains terranes were part of a converging oceanic plate, with only about 20° of rotation in mid‐Tertiary time during Basin and Range extension. No data currently available show evidence for any significant latitudinal displacement of any Klamath Mountains terranes relative to cratonic North America.

California↗

USGS2017

A comparison of age, size, and fecundity of harvested and reference White Sucker populations

White Suckers Catostomus commersonii are an important source of fresh bait for the Maine lobster fishery. The Maine Department of Inland Fisheries and Wildlife began issuing commercial harvest permits in 1991, without reporting requirements or limits on the number of permits. There is recent concern that overfishing may be occurring. To infer impact, we investigated demographic differences between White Sucker populations in lakes open to harvest and those in lakes closed to harvest. Each of three harvested lakes was paired to a nearby closed lake as a reference based on general size, morphometry, and information on harvest pressure. In total, 976 spawning White Suckers were collected from the six lakes in 2014 (120–282 individuals/lake). Fish size, estimated age, fecundity, and mortality rates were compared between lakes. We hypothesized that we would find smaller, younger, and less-fecund individuals in harvested lakes compared to reference lakes. Size and age distributions for both sexes differed between nearly all lake pairs (except between males from one pair). White Suckers from reference lakes were larger and older and had greater gonadosomatic indices and fecundity than fish from harvested lakes. Estimated annual mortality rates were at least twofold higher in harvested lakes than in reference lakes. We detected some differences in von Bertalanffy growth parameters between lake pairs, as might occur under selective harvest pressure. The growth coefficient was smaller for reference lakes than for harvested lakes, while asymptotic length was greater for reference lakes than for harvested lakes. The data suggest that current levels of exploitation are resulting in greater age truncation in existing White Sucker populations.

Maine↗

USGS2014

Reach-scale comparison of habitat and mollusk assemblages for select sites in the Clinch River with regional context

Several hypotheses, including habitat degradation and variation in fluvial geomorphology, have been posed to explain extreme spatial and temporal variation in Clinch River mollusk assemblages. We examined associations between mollusk assemblage metrics (richness, abundance, recruitment) and physical habitat (geomorphology, streambed composition, fish habitat, and riparian condition) at 10 sites selected to represent the range of current assemblage condition in the Clinch River. We compared similar geomorphological units among reaches, employing semi-quantitative and quantitative protocols to characterize mollusk assemblages and a mix of visual assessments and empirical measurements to characterize physical habitat. We found little to no evidence that current assemblage condition was associated with 54 analyzed habitat metrics. When compared to other sites in the Upper Tennessee River Basin (UTRB) that once supported or currently support mollusk assemblages, Clinch River sites were more similar to each other, representing a narrower range of conditions than observed across the larger geographic extent of the UTRB. A post-hoc analysis suggested stream size and average boundary shear stress at bankfull stage may have historically limited species richness in the UTRB (p < 0.001). Associations between mollusk assemblages and physical habitat in the UTRB and Clinch River currently appear obscured by other factors limiting richness, abundance, and recruitment.

Tennessee, Virginia↗

USGS2013

United States-Mexican Borderlands: Facing tomorrow's challenges through USGS science

Along the nearly 3,200 kilometers (almost 2,000 miles) of the United States–Mexican border, in an area known as the Borderlands, we are witnessing the expression of the challenges of the 21st century. This circular identifies several challenge themes and issues associated with life and the environment in the Borderlands, listed below. The challenges are not one-sided; they do not originate in one country only to become problems for the other. The issues and concerns of each challenge theme flow in both directions across the border, and both nations feel their effects throughout the Borderlands and beyond. The clear message is that our two nations, the United States and Mexico, face the issues in these challenge themes together, and the U.S. Geological Survey (USGS) understands it must work with its counterparts, partners, and customers in both countries. Though the mission of the USGS is not to serve as land manager, law enforcer, or code regulator, its innovation and creativity and the scientific and technical depth of its capabilities can be directly applied to monitoring the conditions of the landscape. The ability of USGS scientists to critically analyze the monitored data in search of signals and trends, whether they lead to negative or positive results, allows us to reach significant conclusions—from providing factual conclusions to decisionmakers, to estimating how much of a natural resource exists in a particular locale, to predicting how a natural hazard phenomenon will unfold, to forecasting on a scale from hours to millennia how ecosystems will behave. None of these challenge themes can be addressed strictly by one or two science disciplines; all require well-integrated, cross-discipline thinking, data collection, and analyses. The multidisciplinary science themes that have become the focus of the USGS mission parallel the major challenges in the border region between Mexico and the United States. Because of this multidisciplinary approach, the USGS possesses a unique set of capabilities that can address these challenges. The USGS can apply geographical, geospatial, biological, hydrological, and geological sciences to these complex issues and thereby provide insight into the area’s natural systems and their relation to human activity. As we come to better understand the complexities of the components of these challenge themes, we discover that each part is inextricably intertwined with other overarching issues. Because of the complex interactions of the human, ecological, political, and economic exigencies associated with this area, the status of the Borderlands has become an ever-present concern for most American citizens and for Mexican and United States Federal, State, and local governments. This circular is intended to provide you - citizen, local decisionmaker, government leader, or private entrepreneur—an overview of what the USGS considers the current and future challenges in the United States–Mexican border region and examples of how the USGS can make a difference in understanding and addressing these issues.

United States-Mexico Borderlands↗

USGS2001

U.S. Geological Survey Appalachian region integrated science workshop proceedings, Gatlinburg, Tennessee, October 22-26, 2001

Some of nature's most magnificent creations on Earth are the picturesque landscape and the terrestrial and aquatic inhabitants of the Appalachian Mountains of the Eastern United States. Mother Nature has been kind to the region but man, often, has not. The Appalachian mountains and valleys have been home to a variety of human cultures, dating back approximately 12,000 years. A series of Native American peoples, including most recently the Cherokee Nation, inhabited the region prior to European settlement which began in the 1600's. All of these peoples have had the desire to reap the benefits of the land. Current and historic use of the land ranges from mineral extraction to agricultural development to timber production to industrial and residential development, all of which have now threatened the landscape. Many individuals and organizations desire to save the awe and beauty of the Appalachians for the generations to come, in a way that is environmentally and economically sustainable. They have tried for years to raise alarms that this area is threatened and worth the attention of all who are interested in an effort of restitution and preservation. Residents, environmental groups, land managers, scientists, business groups, and the multitude of visitors who pass through the national parks and other public lands located within the Appalachians have raised these same alarms. There is a need to not only identify the issues resulting from anthropogenic pressures on the landscape, but also to collect the information and conduct the science that will allow land managers and policy makers to become better informed and better able to execute their responsibilities.

Appalachia↗