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Wildlife ecology and management studies have been widely criticized for deficiencies in design or analysis. Manipulative experiments--with controls, randomization, and replication in space and time--provide powerful ways of learning about natural systems and establishing causal relationships, but such studies are rare in our field. Observational studies and sample surveys are...

We determine the crustal structures beneath 14 broad-band seismic stations, deployed in western, eastern, central and southern Iceland, using surface wave dispersion curves and receiver functions. We implement a method to invert receiver functions using constraints obtained from genetic algorithm inversion of surface waves. Our final models satisfy both data...

Classification methods used in machine learning (e.g., artificial neural networks, decision trees, and k-nearest neighbor clustering) are rarely used with population genetic data. We compare different nonparametric machine learning techniques with parametric likelihood estimations commonly employed in population genetics for purposes of assigning individuals to their population...

Several potential dust sources, including generic sources of sparsely vegetated alluvium, playa deposits, and anthropogenic emissions, as well as the area around Owens Lake, California, affect the composition of modern dust in the southwestern United States. A comparison of geochemical analyses of modern and old (a few thousand years) dust...

The “Mitten” (provisionally named Murias Chaos by the International Astronomical Union) is a region of elevated chaos-like terrain in the leading hemisphere of Europa. Its origin had been explained under the currently debated theories of melting through a thin lithosphere or convection within a thick one. Galileo observations reveal several...

Riparian plant community composition is influenced by moisture, erosion, original native plant communities, and current and past land use. This study compared riparian plant communities under four types of management: woody buffer strip, grassy buffer strip, rotational grazing, and continuous grazing. Study sites were located along spring-fed streams in the...

Mapping land cover of large regions often requires processing of satellite images collected from several time periods at many spectral wavelength channels. However, manipulating and processing large amounts of image data increases the complexity and time, and hence the cost, that it takes to produce a land cover map. Very...

Aim: We evaluated how an elevation gradient affects: (1) the availability of food required by a specialist seed-eater, Loxioides bailleui Oustalet (Drepanidinae), or pallia, and hence the distribution of this endangered Hawaiian bird, and (2) the distribution of alien threats to Loxioides populations, their primary foods, and their dry-forest habitat,...

To provide the first nationwide reconnaissance of the occurrence of pharmaceuticals, hormones, and other organic wastewater contaminants (OWCs) in water resources, the U.S. Geological Survey used five newly developed analytical methods to measure concentrations of 95 OWCs in water samples from a network of 139 streams across 30 states during...

Shishaldin Volcano, in the central Aleutian volcanic arc, became seismically restless during the summer of 1998. Increasing unrest was monitored using a newly installed seismic network, weather satellites, and rare local visual observations. The unrest culminated in large eruptions on 19 April and 22-23 April 1999. The opening phase of...

Freshwater mussels and stream substrate were sampled at 30 locations in the Apalachicola, Chattahoochee, and Flint (ACF) river basins. Although >2100 mussels that included 25 species were observed in our sample of 2661 quadrats, only 5 species were sufficiently abundant to provide reliable estimates of the relationship between mussel presence...

Through combination of surface wave and body wave constraints we derive a three-dimensional (3-D) crustal S velocity model and Moho map for Iceland. It reveals a vast plumbing system feeding mantle plume melt into upper crustal magma chambers where crustal formation takes place. The method is based on the partitioned waveform inversion...

First and last occurrences of several Maastrichtian calcareous nannofossil species are shown to be diachronous across paleodepth and paleoenvironment using the graphic correlation method. Calcareous nannofossil assemblages examined from eleven cores from a deep- to shallow-water transect along the eastern United States Atlantic margin document that the first occurrence of...

Oligochaetes, triactinomyxons (TAMs), and age-0 trout were sampled in the upper Cache la Poudre River, Colorado, to determine the distribution of Myxobolus cerebralis during 1997 and 1998. Densities of the intermediate host, the oligochaete Tubifex tubifex, were 3.5 orders of magnitude higher in the M. cerebralis-infected Poudre Rearing Unit (PRU) trout rearing ponds than...

Information on the habitat requirements and effects of habitat management on wetland birds were summarized from information in more than 500 published and unpublished papers. A range map is provided to indicate the relative densities of the species in North America, based on Breeding Bird Survey (BBS) data. Although the...

Information on the habitat requirements and effects of habitat management on wetland birds were summarized from information in more than 500 published and unpublished papers. A range map is provided to indicate the relative densities of the species in North America, based on Breeding Bird Survey (BBS) data. Although the...

Was the pre-European Southwest a region of wild landscapes, shaped primarily by natural processes like lightning-ignited fire, or did people substantially mold these lands into regional-scale artifacts through their use of fire and other means? Perspectives on this question have varied markedly through time and between scholars, as evident from...

Information on the habitat requirements and effects of habitat management on wetland birds were summarized from information in more than 500 published and unpublished papers. A range map is provided to indicate the relative densities of the species in North America, based on Breeding Bird Survey (BBS) data. Although the...

Information on the habitat requirements and effects of habitat management on grassland birds were summarized from information in more than 5,500 published and unpublished papers. A range map is provided to indicate the relative densities of the species in North America, based on Breeding Bird Survey (BBS) data. Although birds...

Water-quality samples were collected quarterly during 1994-99 from 604 wells screened in the surficial aquifer system beneath the Charleston Naval Complex, North Charleston, South Carolina. Arsenic and thallium were selected for analysis because concentrations of these metals in some wells consistently exceeded the established (2001) drinking water maximum contaminant levels of 10 and 2 micrograms per liter, respectively....

A survey of methods used by US state agencies for collecting and processing benthic macroinvertebrate samples from streams was conducted by questionnaire; 90 responses were received and used to describe trends in methods. The responses represented an estimated 13,000-15,000 samples collected and processed per year. Kicknet devices were used in...

Open File Report 01-480 was designed as a large format poster for the Annual Meeting of the American Association of Petroleum Geologists and the Society for Sedimentary Geology in Denver Colorado in June 2001. It is reproduced here in digital format to make widely available some unique images of...

Three borehole flowmeters and hydrophysical logging were used to measure ground-water flow in carbonate bedrock at sites in southeastern Indiana and on the west-central border of Kentucky and Tennessee. The three flowmeters make point measurements of the direction and magnitude of horizontal flow, and hydrophysical logging measures the magnitude of...

This preliminary experimental lithogeochemical map shows the distribution of rock types in the Virginia and Maryland parts of the Chesapeake Bay watershed. The map was produced digitally by classifying geologic-map units according to composition, mineralogy, and texture; rather than by age and stratigraphic relationships as shown on traditional geologic maps....

The availability of relevant and accurate environmental information is essential for environmental policy-makers. Recent improvements in satellite remote sensing technologies, groundbased monitors, and data access have resulted in the ability to observe and assess major atmospheric and ecological events around the world on a timely basis Each of these monitoring...