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At least 307 records · Page 17Linked to original sources

USGS1984

Geochemical survey of the Lusk Creek Roadless Area, Pope County, Illinois

The Lusk Creek Roadless Area (Index map) lies along the western edge of the Illinois-Kentucky fluorspar district in which flourite deposits occur as lenticular-type veins emplaced along fult zones or as tratiform-shaped bedding-replacement deposits that occur along fault zones (Grogan and Bradbury, 1967; Trace, 1974). Although mineralogy varies between deposits, Trace (1974) points out that the principal minerals are fluorite (CaF) and calcite (CaCO 3 ), and associated with these minerals are lesser amounts of sphalerite (ZnS), galena (PbS), and barite (BaSO 4 ). Minor quantites of iron-rich dolomite (CaMg(CO 3 ) 2 ), pyrite (Fe S 2 ), and alteration products of zinc, lead, and copper minerals also are found.

Illinois↗

USGS2019

Contact rates with nesting birds before and after invasive snake removal: Estimating the effects of trap-based control

Invasive predators are responsible for almost 60% of all vertebrate extinctions worldwide with the most vulnerable faunas occurring on islands. The brown treesnake ( Boiga irregularis ) is a notorious invasive predator that caused the extirpation or extinction of most native forest birds on Guam. The success of avian reintroduction efforts on Guam will depend on whether snake-control techniques sufficiently reduce contact rates between brown treesnakes and reintroduced birds. Mouse-lure traps can successfully reduce brown treesnake populations at local scales. Over a 22-week period both with and without active snake removal, we evaluated snake-trap contact rates for mouse- and bird-lure traps. Bird-lure traps served as a proxy for reintroduced nesting birds. Overall, mouse-lure traps caught more snakes per trap night than did bird-lure traps. However, cameras revealed that bird-lure traps had a snake contact rate almost 15 times greater than the number of successfully captured snakes. Snakes that entered bird-lure traps tended to be larger and in better body condition and were mostly captured in bird-lure traps, despite numerous adjacent mouse-lure traps. Traps placed along grid edges caught more snakes than interior traps, suggesting continuous immigration into the trapping grid within which bird-lure traps were located. Contact between snakes and bird-lure traps was equivalent before and after snake removal, suggesting mouse-lure traps did not adequately reduce the density of snakes that posed a risk to birds, at least at the timescale of this project. This study provides evidence that some snakes exhibit prey selectivity for live birds over live mouse lures. Reliance on a single control tool and lure may be inadequate for support of avian reintroductions and could lead to unintended harvest-driven trait changes of this invasive predator.

NeoBiota↗

USGS2010

Structure of the collision zone between Bougainville guyot and the accretionary wedge of the New Hebrides Island arc, southwest Pacific

Multichannel seismic reflection data show the structure that develops within an island arc-guyot collision zone. The Bougainville guyot fills the New Hebrides trench, stands about 3 km above the abyssal ocean plain, and is capped by a broad platform that is underlain by a parallel bedded sequence, probably lagoon and reef rocks. A thick debris apron made up of unconsolidated sediment underlies the unsubducted part of the lower guyot flank and possibly the subducted flank as well. The contact zone between the arc and the north and east sides of the guyot is marked by discontinuous antiforms that include reflective, thrust faulted rocks that may have been derived from the guyot. The extent of collision deformation to the arc and guyot depends in part on the contrast in compressibility and viscosity between these features. We propose that the high-drag, subcircular guyot evolves during collision into a more streamlined shape. Streamlining may be achieved by processes like: (1) bulk deformation of the guyot by thrust faulting and sediment compaction; (2) ripping away of projecting parts of the guyot and blunting sharp edges (tectonic erosion), like that formed by the limestone cap; and (3) formation of a boundary layer, between the guyot and the arc, that is made up of water-rich, mobilized units of soft sediment. We draw an analogy between some features of glacial origin and the subducted part of a guyot. If the bulk of the guyot is low strength, especially in view of the thick debris apron, then the guyot may behave like till that was overridden by a glacier and forms a drumlin, an elongated, blunt-faced, streamlined feature. Thrust faults evident in the guyot may indicate deformation that leads toward a streamlined shape and not necessarily to accretion of guyot rocks.

Tectonics↗

USGS1979

Mineral resources of the Minarets Wilderness and adjacent areas, Madera and Mono counties, California

A mineral survey of the Minarets Wilderness area and adjacent areas in the central Sierra Nevada, Calif., was conducted during 1973 through 1975. The total area covers about 620 km 2 (237 sq mi) in the Sierra and Inyo National Forests, of which about 440 km 2 (170 sq mi) are within the officially designated Minarets Wilderness. The mineral resource potential was evaluated by geological, geochemical, and geophysical studies by the U.S. Geological Survey, and by examination of mineralized rocks, prospects, and mining claims by the U.S. Bureau of Mines. The results of the survey indicate that the study area has small to moderate submarginal to paramarginal resources of copper, silver, zinc, lead, iron, and tungsten and an unevaluated potential for molybdenum resources. Limestone is present, but not of commercial quantity or quality. No other industrial minerals have been recognized in quantity. Granitic rocks have potential use as decorative stone and sand and gravel could be produced from either alluvial deposits or glacial drift. However, these commodities are more accessible elsewhere at localities closer to markets. The study area has no potential for fossil fuels, and, because of the general geologic environment, the potential for nuclear fuel minerals is considered to be low. The study area has low geothermal potential, even though it is on the western edge of the Mono-Long Valley "Known Geothermal Resource Area" (KGRA). The area is underlain by metavolcanic and metasedimentary rocks that have been intruded by granitic rocks of the Sierra Nevada batholith. Pliocene volcanic rocks are present locally. With few exceptions, the known occurrences of mineralized rock are confined to the metamorphic rocks, and the exceptions appear to be confined to plutonic rocks that are older than the Late Cretaceous granitic rocks that make up the bulk of the batholithic rocks in the study area. Although no mineral production has been recorded from prospects within the study area, mines adjacent to it have produced significant amounts of gold and tungsten. Production figures are incomplete, but mines in the Mammoth mining district (fig. 1) may have produced as much as $1 million worth of gold, silver, and other metals at the then-existing prices. The Monte Cristo mine in the Mammoth district was in production during 1978.

California↗

USGS2008

Uranium-Lead Zircon Ages and Sr, Nd, and Pb Isotope Geochemistry of Selected Plutonic Rocks from Western Idaho

Across the Salmon River suture in western Idaho, where allochthonous Permian to Cretaceous oceanic rocks are juxtaposed against Proterozoic North American rocks, a wide variety of plutonic rocks are exposed. Available data indicate much variation in composition, source, and structural state of these plutons. The plutonic rocks were long described as the western border zone of the Cretaceous Idaho batholith but limited pre-existing age data indicate more complicated origins. Because the affinity and age of the plutonic rocks cannot be reliably determined from field relations, TIMS U-Pb dating in conjunction with Sr, Nd, and Pb isotopic studies of selected plutons across the suture in western Idaho were undertaken. The data indicate three general groups of plutons including (1) those that intruded the island arc terranes during the Triassic and Jurassic, those that intruded near the western edge of oceanic rocks along the suture in the Early Cretaceous, and the plutons of the Idaho batholith that intruded Proterozoic North American rocks in the Late Cretaceous. Plutons that intruded Proterozoic North American rocks commonly include xenocrystic zircons and in several cases, ages could not be determined. The least radiogenic Sr and most radiogenic Nd are found among the Blue Mountains superterrane island arc samples. Suture-zone plutons have isotopic characteristics that span the range between Idaho batholith and island arc samples but mostly follow island arc signatures. Plutons of the Idaho batholith have the most radiogenic initial Pb and Sr ratios and the least radiogenic Nd of the samples analyzed.

Open-File Report↗

USGS2009

The 2006-2007 Kuril Islands great earthquake sequence

[1] The southwestern half of a ∼500 km long seismic gap in the central Kuril Island arc subduction zone experienced two great earthquakes with extensive preshock and aftershock sequences in late 2006 to early 2007. The nature of seismic coupling in the gap had been uncertain due to the limited historical record of prior large events and the presence of distinctive upper plate, trench and outer rise structures relative to adjacent regions along the arc that have experienced repeated great interplate earthquakes in the last few centuries. The intraplate region seaward of the seismic gap had several shallow compressional events during the preceding decades (notably an M S 7.2 event on 16 March 1963), leading to speculation that the interplate fault was seismically coupled. This issue was partly resolved by failure of the shallow portion of the interplate megathrust in an M W = 8.3 thrust event on 15 November 2006. This event ruptured ∼250 km along the seismic gap, just northeast of the great 1963 Kuril Island (M w = 8.5) earthquake rupture zone. Within minutes of the thrust event, intense earthquake activity commenced beneath the outer wall of the trench seaward of the interplate rupture, with the larger events having normal-faulting mechanisms. An unusual double band of interplate and intraplate aftershocks developed. On 13 January 2007, an M W = 8.1 extensional earthquake ruptured within the Pacific plate beneath the seaward edge of the Kuril trench. This event is the third largest normal-faulting earthquake seaward of a subduction zone on record, and its rupture zone extended to at least 33 km depth and paralleled most of the length of the 2006 rupture. The 13 January 2007 event produced stronger shaking in Japan than the larger thrust event, as a consequence of higher short-period energy radiation from the source. The great event aftershock sequences were dominated by the expected faulting geometries; thrust faulting for the 2006 rupture zone, and normal faulting for the 2007 rupture zone. A large intraplate compressional event occurred on 15 January 2009 (M w = 7.4) near 45 km depth, below the rupture zone of the 2007 event and in the vicinity of the 16 March 1963 compressional event. The fault geometry, rupture process and slip distributions of the two great events are estimated using very broadband teleseismic body and surface wave observations. The occurrence of the thrust event in the shallowest portion of the interplate fault in a region with a paucity of large thrust events at greater depths suggests that the event removed most of the slip deficit on this portion of the interplate fault. This great earthquake doublet demonstrates the heightened seismic hazard posed by induced intraplate faulting following large interplate thrust events. Future seismic failure of the remainder of the seismic gap appears viable, with the northeastern region that has also experienced compressional activity seaward of the megathrust warranting particular attention.

Journal of Geophysical Research B: Solid Earth↗

USGS1971

On the nature of the Boulder Batholith of Montana

In a recent review of the nature of batholiths, Hamilton and Myers (1967) interpreted the Boulder batholith of western Montana to be "in effect a gigantic mantled lava flow .... only a few kilometers thick," that flowed, under a crust of its own ejecta, across a broad structural basin. Such an interpretation is inconsistent with abundant geologic and geophysical data. The main mass of the batholith, the Butte Quartz Monzonite, does not have the characteristics of a lava flow or a laterally emplaced sheet. Its volcanic cover was not a floating cap but a laterally stable roof that was part of a volcanic plateau which occupied at least twice the area of the batholith. It does not thin toward its edges but is generally steep sided. Its flow structures are predominantly steep rather than near horizontal. It is separated from two smaller flanking plutons by thin vertical septa kilometers long. Its emplacement required more than 4 m.y., a rate orders of magnitude too slow for a single sheet only a few kilometers thick, however extensive. The batholith is more than a few kilometers thick. Recent gravity studies (Burfeind, 1967; Bonini, 1969) suggest a maximum thickness of 9 to 15 km to their authors, but the calculations are based on (1) assumed lateral and vertical homogeneity of the batholith, whereas in reality the Butte Quartz Monzonite core is discontinuously rimmed by more mafic, denser plutons; and (2) inappropriate densities, leading to excessive apparent density contrasts. The gravity data suggest to us that the batholith is more than 15 km thick. Heat flow, cooling rate, and seismic data also are compatible with a thickness of at least 15 km, but are difficult to reconcile with a thickness of only a few kilometers. Convincing examples of extrusive or quasi-extrusive thin batholiths must be sought elsewhere. © 1971, The Geological Society of America, Inc.

Montana↗

USGS2007

Ground water redox zonation near La Pine, Oregon: Relation to river position within the aquifer–riparian zone continuum

Increasing residential development since in the 1960s has lead to increases in nitrate concentrations in shallow ground water in parts of the 247 square mile study area near La Pine, Oregon. Denitrification is the dominant nitrate-removal process that occurs in suboxic ground water, and suboxic ground water serves as a barrier to transport of most nitrate in the aquifer. Oxic ground water, on the other hand, represents a potential pathway for nitrate transport from terrestrial recharge areas to the Deschutes and Little Deschutes Rivers. The effects of present and potential future discharge of ground-water nitrate into the nitrogen-limited Deschutes and Little Deschutes Rivers are not known. However, additions of nitrogen to nitrogen-limited rivers can lead to increases in primary productivity which, in turn, can increase the magnitudes of dissolved oxygen and pH swings in river water. An understanding of the distribution of oxic ground water in the near-river environment could facilitate understanding the vulnerability of these rivers and could be a useful tool for management of these rivers. In this study, transects of temporary wells were installed in sub-river sediments beneath the Deschutes and Little Deschutes Rivers near La Pine to characterize near-river reduction/oxidation (redox) conditions near the ends of ground-water flow paths. Samples from transects installed near the center of the riparian zone or flood plain were consistently suboxic. Where transects were near edges of riparian zones, most ground-water samples also were suboxic. Oxic ground water (other than hyporheic water) was uncommon, and was only detected near the outside edge of some meander bends. This pattern of occurrence likely reflects geochemical controls throughout the aquifer as well as geochemical processes in the microbiologically active riparian zone near the end of ground-water flow paths. Younger, typically less reduced ground water generally enters near-river environments through peripheral zones, whereas older, typically more reduced ground water tends to discharge closer to the center of the river corridor. Such distributions of redox state reflect ground-water movement and geochemical evolution at the aquifer-scale. Redox state of ground water undergoes additional modification as ground water nears discharge points in or adjacent to rivers, where riparian zone processes can be important. Lateral erosion of river systems away from the center of the flood plain can decrease or even eliminate interactions between ground water and reducing riparian zone sediments. Thus, ground water redox patterns in near-river sediments appear to reflect the position of a river within the riparian zone/aquifer continuum. Spatial heterogeneity of redox conditions near the river/aquifer boundary (that is, near the riverbed) makes it difficult to extrapolate transect-scale findings to a precise delineation of the oxic-suboxic boundary in the near-river environment of the entire study area. However, the understanding of relations between near-river redox state and proximity to riparian zone edges provides a basis for applying these results to the study-area scale, and could help guide management efforts such as nitrogen-reduction actions or establishment of Total Maximum Daily Load criteria. Coupling the ground-water redox-based understanding of river vulnerability with ground-water particle-tracking-based characterization of connections between upgradient recharge areas and receiving rivers demonstrates one means of linking effects of potential nitrate loads at the beginning of ground-water flow paths with river vulnerability.

Oregon↗

USGS2007

Native Fish Sanctuary Project - Sanctuary Development Phase, 2007 Annual Report

Notable progress was made in 2007 toward the development of native fish facilities in the Lower Colorado River Basin. More than a dozen facilities are, or soon will be, online to benefit native fish. When this study began in 2005 no self-supporting communities of either bonytail or razorback sucker existed. Razorback suckers were removed from Rock Tank in 1997 and the communities at High Levee Pond had been compromised by largemouth bass in 2004. This project reversed that trend with the establishment of the Davis Cove native fish community in 2005. Bonytail and razorback sucker successfully produced young in Davis Cove in 2006. Bonytail successfully produced young in Parker Dam Pond in 2007, representing the first successful sanctuary established solely for bonytail. This past year, Three Fingers Lake received 135 large razorback suckers, and Federal and State agencies have agreed to develop a cooperative management approach dedicating a portion of that lake toward grow-out and (or) the establishment of another sanctuary. Two ponds at River's Edge Golf Course in Needles, California, were renovated in June and soon will be stocked with bonytail. Similar activities are taking place at Mohave Community College, Cerbat Cliffs Golf Course, Cibola High Levee Pond, Office Cove, Emerald Canyon Golf Course, and Bulkhead Cove. Recruitment can be expected as fish become sexually mature at these facilities. Flood-plain facilities have the potential to support 6,000 adult razorback suckers and nearly 20,000 bonytail if native fish management is aggressively pursued. This sanctuary project has assisted agencies in developing 15 native fish communities by identifying specific resource objectives for those sites, listing and prioritizing research opportunities and needs, and strategizing on management approaches through the use of resource-management plans. Such documents have been developed for Davis Cove, Cibola High Levee Pond, Parker Dam Pond, and Three Fingers Lake. We anticipate similar documents will be developed in the near future for River's Edge Golf Course Ponds, Office Cove, Emerald Canyon Golf Course Ponds, Bulkhead Cove, Mohave Community College, and Cerbat Cliffs Golf Course ponds as these facilities come on line or are developed in the future. The following report discusses the process that went into the development of these facilities. Sites were visited, assessed as to their suitability based on the control of nonnative predators, habitat suitability, conversion cost, logistics, geographical location, and willingness of landowners. They were then prioritized according to their suitability, cost, timely conversion, and willingness of landowners. Existing native fish facilities were included in this evaluation for their value in helping to determine physical and biological parameter ranges. This report describes the approaches that led to success, those leading to failure, and some of the biological, institutional, and management issues of implementing native fish sanctuary development.

Open-File Report↗

USGS2014

Landscape alterations influence differential habitat use of nesting buteos and ravens within sagebrush ecosystem: implications for transmission line development

A goal in avian ecology is to understand factors that influence differences in nesting habitat and distribution among species, especially within changing landscapes. Over the past 2 decades, humans have altered sagebrush ecosystems as a result of expansion in energy production and transmission. Our primary study objective was to identify differences in the use of landscape characteristics and natural and anthropogenic features by nesting Common Ravens ( Corvus corax ) and 3 species of buteo (Swainson's Hawk [ Buteo swainsoni ], Red-tailed Hawk [ B. jamaicensis ], and Ferruginous Hawk [ B. regalis ]) within a sagebrush ecosystem in southeastern Idaho. During 2007–2009, we measured multiple environmental factors associated with 212 nest sites using data collected remotely and in the field. We then developed multinomial models to predict nesting probabilities by each species and predictive response curves based on model-averaged estimates. We found differences among species related to nesting substrate (natural vs. anthropogenic), agriculture, native grassland, and edge (interface of 2 cover types). Most important, ravens had a higher probability of nesting on anthropogenic features (0.80) than the other 3 species (<0.10), and the probability of nesting near agriculture was greatest for ravens (0.55) followed by Swainson's Hawk (0.28). We also describe changes in nesting densities over 4 decades at this site as related to natural and anthropogenic disturbances. Since the 1970s, the composition of the raptor and raven nesting community has drastically changed with anthropogenic alterations and loss of continuous stands of sagebrush ( Artemisia spp.), favoring increased numbers of nesting ravens and fewer nesting Ferruginous Hawks. Our results indicate that habitat alterations, fragmentation, and forthcoming disturbances anticipated with continued energy development in sagebrush steppe ecosystems can lead to predictable changes in raptor and raven communities.

Idaho↗

USGS2011

National Climate Change and Wildlife Science Center project accomplishments: highlights

The National Climate Change and Wildlife Science Center (NCCWSC) has invested more than $20M since 2008 to put cutting-edge climate science research in the hands of resource managers across the Nation. With NCCWSC support, more than 25 cooperative research initiatives led by U.S. Geological Survey (USGS) researchers and technical staff are advancing our understanding of habitats and species to provide guidance to managers in the face of a changing climate. Projects focus on quantifying and predicting interactions between climate, habitats, species, and other natural resources such as water. Spatial scales of the projects range from the continent of North America, to a regional scale such as the Pacific Northwest United States, to a landscape scale such as the Florida Everglades. Time scales range from the outset of the 20th century to the end of the 21st century. Projects often lead to workshops, presentations, publications and the creation of new websites, computer models, and data visualization tools. Partnership-building is also a key focus of the NCCWSC-supported projects. New and on-going cooperative partnerships have been forged and strengthened with resource managers and scientists at Federal, tribal, state, local, academic, and non-governmental organizations. USGS scientists work closely with resource managers to produce timely and relevant results that can assist managers and policy makers in current resource management decisions. This fact sheet highlights accomplishments of five NCCWSC projects.

Fact Sheet↗

USGS2007

Three-dimensional geophysical mapping of rock alteration and water content at Mount Adams, Washington: Implications for lahar hazards

[1] Hydrothermally altered rocks, particularly if water saturated, can weaken stratovolcanoes, thereby increasing the potential for catastrophic sector collapses that can lead to far-traveled, destructive debris flows. Evaluating the hazards associated with such alteration is difficult because alteration has been mapped on few active volcanoes and the distribution and intensity of subsurface alteration are largely unknown on any active volcano. At Mount Adams, some Holocene debris flows contain abundant hydrothermal minerals derived from collapse of the altered edifice. Intense hydrothermal alteration significantly reduces the resistivity and magnetization of volcanic rock, and therefore hydrothermally altered rocks can be identified with helicopter electromagnetic and magnetic measurements. Electromagnetic and magnetic data, combined with geological mapping and rock property measurements, indicate the presence of appreciable thicknesses of hydrothermally altered rock in the central core of Mount Adams north of the summit. We identify steep cliffs at the western edge of this zone as the likely source for future large debris flows. In addition, the electromagnetic data identified water in the brecciated core of the upper 100–200 m of the volcano. Water helps alter the rocks, reduces the effective stress, thereby increasing the potential for slope failure, and acts, with entrained melting ice, as a lubricant to transform debris avalanches into lahars. Therefore knowing the distribution of water is also important for hazard assessments. Our results demonstrate that high-resolution geophysical and geological observations can yield unprecedented views of the three-dimensional distribution of altered rock and shallow pore water aiding evaluation of the debris avalanche hazard.

Journal of Geophysical Research B: Solid Earth↗

USGS2007

Linking occurrence and fitness to persistence: Habitat-based approach for endangered Greater Sage-Grouse

Detailed empirical models predicting both species occurrence and fitness across a landscape are necessary to understand processes related to population persistence. Failure to consider both occurrence and fitness may result in incorrect assessments of habitat importance leading to inappropriate management strategies. We took a two-stage approach to identifying critical nesting and brood-rearing habitat for the endangered Greater Sage-Grouse (Centrocercus urophasianus) in Alberta at a landscape scale. First, we used logistic regression to develop spatial models predicting the relative probability of use (occurrence) for Sage-Grouse nests and broods. Secondly, we used Cox proportional hazards survival models to identify the most risky habitats across the landscape. We combined these two approaches to identify Sage-Grouse habitats that pose minimal risk of failure (source habitats) and attractive sink habitats that pose increased risk (ecological traps). Our models showed that Sage-Grouse select for heterogeneous patches of moderate sagebrush cover (quadratic relationship) and avoid anthropogenic edge habitat for nesting. Nests were more successful in heterogeneous habitats, but nest success was independent of anthropogenic features. Similarly, broods selected heterogeneous high-productivity habitats with sagebrush while avoiding human developments, cultivated cropland, and high densities of oil wells. Chick mortalities tended to occur in proximity to oil and gas developments and along riparian habitats. For nests and broods, respectively, approximately 10% and 5% of the study area was considered source habitat, whereas 19% and 15% of habitat was attractive sink habitat. Limited source habitats appear to be the main reason for poor nest success (39%) and low chick survival (12%). Our habitat models identify areas of protection priority and areas that require immediate management attention to enhance recruitment to secure the viability of this population. This novel approach to habitat-based population viability modeling has merit for many species of concern. ?? 2007 by the Ecological Society of America.

Ecological Applications↗

USGS2019

Tracking phosphorus and sediment sources and transport from fields and channels in Great Lakes Restoration Initiative priority watersheds

A multi-agency, integrated series of studies were initiated in 2017 under the Great Lakes Restoration Initiative (GLRI) by the U.S. Geological Survey, U.S. Forest Service, and the University of Minnesota to quantify the source, downstream travel time, and storage of particulate-bound phosphorus and sediment in agricultural tributaries to the Great Lakes. Of particular interest are contributions at the edge of field, channels, and riparian corridors. Results will be used to help identify upland and stream conservation practices that may reduce phosphorus and sediment inputs to the Great Lakes. The two study watersheds are the 50 km2 Black Creek in the Maumee River basin (Lake Erie) and the 90 km2 Plum Creek in the Lower Fox River basin (Lake Michigan). As part of other GLRI work, Black Creek and Plum Creek have existing, nested, edge-of-field studies in addition to phosphorus and sediment monitoring stations along their mainstems. Sediment-source tracking provides a direct method to quantify suspended sediment, and consequently phosphorus, sources by identifying a minimal set of properties (or fingerprint) that uniquely defines each source of sediment in the basin. This fingerprint can then be used to apportion sources of sediment from agricultural fields as well as other uplands including developed areas, forests, and pastures. These methods can also help distinguish sediment from ditches, ravines and eroding slopes, and streambanks. Multiple tracking methods are being used and adapted for best results in these watersheds, including a suite of trace elements for overall source apportionment in addition to short-term fallout radionuclides beryllium-7 (7Be) and lead-210 (210Pb) for high-flow event-based transport on fields and in stream channels. Tile drain connectivity to the surface is also of interest, especially in the Black Creek watershed. Preliminary results from the overall source apportionment from analyses of streambed sediment and monthly suspended sediment in Plum Creek indicate that the proportion attributed to different land cover varied by season and events. Further data analyses are being conducted for examining event-based pathways on individual fields, while most basin-wide sampling was monthly. Results from both watersheds will help describe the variations in transport of particulate-bound phosphorus across both steep and gentle landscapes representative of the Great Lakes basin. (this is from IP-101450)

Great Lakes↗

USGS1972

Reconnaissance geology of the Bi'r Al Badriyah quadrangle, Kingdom of Saudi Arabia

The Bi'r al Badriyah quadrangle covers an area of 2843 sq km in the extreme eastern part of the Precambrian Shield in central Saudi Arabia. The Precambrian rocks in the southeastern part of the area are unconformably overlain by limestone of Permian age, which occupies only a small part of the quadrangle. Three great sequences of Precambrian rocks are recognized and called, from oldest to youngest, the Halaban Group, the Bi'r Khountina Group, and the Murdama Group. From evidence within the quadrangle itself the three groups are seen to be separated by erosional unconformities, and the Halaban and Bi'r Khountina Groups are intruded by granitic and gabbroic plutonic rocks and a wide variety of dikes. Exposures north of the quadrangle show that the Murdama Group is also intruded by granitic rocks. The Halaban Group, consists of three formations called, from oldest to youngest, the Umm Mushraha Formation, the Jebal al Egfool Formation, and the Wadi al Jifr Formation. These rocks are variably metamorphosed, but characteristically they are at the epidote-albite amphibolite facies of regional metamorphism, are polymetamorphic, and rest unconformably on ancient granite gneiss. The Umm Mushraha Formation consists of amphibolite, schistose andesite, and greenstone associated with minor meta-agglomerate, meta-graywacke, and marble. The Jebal al Egfool Formation consists of sheared and metamorphosed volcanic rocks of intermediate composition, and the Wadi al Jifr Formation is made up of metamorphosed felsic volcanic rocks. Rocks of the Bi'r Khountina Group are rather similar to the Halaban Group in original composition, but they are separated from the Halaban by an angular unconformity and have distinctive formations of conglomerate (the Idsas Formation), marble (the Fawara Formation), and graywacke (the Abu Sawarir Formation) at the base. Most of the Bi'r Khountina Group consists of andesitic volcanic rocks in the Badriyah Formation. Mostly, the Bi'r Khountina Group is unmetamorphosed or feebly metamorphosed to the greenschist facies. Locally, as in the aureole of intrusive rocks, the Bi'r Khountina Group reaches higher metamorphic grades. The rocks of the Murdama Group unconformably overlie the Bi'r Khountina Group, and basal conglomerates of the Murdama contain fragments of distinctive rocks intrusive into the Bi'r Khountina. The Murdama Group is composed of the Z'relba Formation, Consisting of conglomerate and schistose conglomerate and the Abt Formation, a thick sequence of laminated, mainly fine-grained, sedimentary rocks. Metamorphism in .the Murdama increases toward the north, and along the north edge of the area the Murdama Group is represented by chlorite-sericite schists. Three major episodes of folding are recorded in the Precambrian rocks. The earliest episode folded the rocks of the Halaban Group along north-trending axes which are now truncated by the unconformity at the base of the Bi'r Khountina Group. After the rocks of the Bi'r Khountina and Murdama Groups were deposited, the three groups were folded along northwest-trending axes of regional scale. Later, possibly at a time of major faulting along a northwesterly direction, the rocks were again folded on north-trending axes. Samples of rock materials collected at 105 localities in the quadrangle were analyzed for 27 elements. Only one anomalous value was found: a low positive anomaly for lead at the Umm Mushraha gold mine. Threshold amounts of Ag, B, Cr, Cu, La, Mn, Mo, NI, Sc, Sn, Ti, V, and Zr were detected. The distribution of copper and molybdenum suggests that two plutons of biotite-hornblende granite in the central part of the quadrangle, and the rocks between them, should be examined for possible disseminated copper and molybdenum of the porphyry type. The distribution of scandium and detrital scheelite suggests that a zone adjacent to phyllonite in the northeastern quarter of the quadrangle be examined for tungsten associated with amphibolite.

Open-File Report↗

USGS2018

The genetic network of greater sage-grouse: Range-wide identification of keystone hubs of connectivity

Genetic networks can characterize complex genetic relationships among groups of individuals, which can be used to rank nodes most important to the overall connectivity of the system. Ranking allows scarce resources to be guided toward nodes integral to connectivity. The greater sage-grouse (Centrocercus urophasianus) is a species of conservation concern that breeds on spatially discrete leks that must remain connected by genetic exchange for population persistence. We genotyped 5,950 individuals from 1,200 greater sage-grouse leks distributed across the entire species’ geographic range. We found a small-world network composed of 458 nodes connected by 14,481 edges. This network was composed of hubs—that is, nodes facilitating gene flow across the network—and spokes—that is, nodes where connectivity is served by hubs. It is within these hubs that the greatest genetic diversity was housed. Using indices of network centrality, we identified hub nodes of greatest conservation importance. We also identified keystone nodes with elevated centrality despite low local population size. Hub and keystone nodes were found across the entire species’ contiguous range, although nodes with elevated importance to network-wide connectivity were found more central: especially in northeastern, central, and southwestern Wyoming and eastern Idaho. Nodes among which genes are most readily exchanged were mostly located in Montana and northern Wyoming, as well as Utah and eastern Nevada. The loss of hub or keystone nodes could lead to the disintegration of the network into smaller, isolated subnetworks. Protecting both hub nodes and keystone nodes will conserve genetic diversity and should maintain network connections to ensure a resilient and viable population over time. Our analysis shows that network models can be used to model gene flow, offering insights into its pattern and process, with application to prioritizing landscapes for conservation.

Idaho, Wyoming, Montana, Utah, Nevada↗

USGS2015

Plethodon cinerius (eastern red-backed salamander) movement

Lungless salamanders (family Plethodontidae) are relatively sedentary and are presumed to have limited dispersal ability (Marsh et al. 2004. Ecology 85:3396–3405). Site fidelity in Plethodontidae is high, and individuals displaced 90 m return to home territories (Kleeberger and Werner 1982. Copeia 1982:409–415). Individuals defend territories (Jaeger et al. 1982. Anim. Behav. 30:490–496) and female home ranges have been estimated to be 24.34 m2 (Kleeberger and Werner 1982, op. cit.). Females may seek out suitable subsurface habitat to oviposit eggs, yet little is known about their maximum movement distances (Petranka 1998. Salamanders of the United States and Canada. Smithsonian Institution Press, Washington. 587 pp.). On 18 September 2014, a female P. cinereus (lead back morphotype; SVL = 44.68 mm; 0.89 g) was found under a coverboard during a standard sampling event and uniquely marked using visual implant elastomer at the S.O. Conte Anadromous Fish Research Center, Massachusetts, USA (42.59280°N, 72.58070°W, datum WGS84; elev. 74 m). This individual was subsequently recaptured at ~1500 h on 8 October 2014 under a coverboard within 3 m of the original capture location and then again ~1430 h on 16 October 2014 under a log, within the same forest patch, though in a 50 x 150 m area adjacent to the original study area. Because we found the marked salamander while collecting multiple individuals for a laboratory study, the exact recapture location of the marked individual is not known. However, the distance between the 8 October capture location and the nearest edge of the 16 October search area (i.e. 50 x 150 m) was 143 m, indicating a minimum movement distance. As far as we are aware, this is the longest recorded movement for P. cinereus by more than 53 m (Kleeberger and Werner 1982, op. cit.). This finding followed a rain event of 1.63 cm within 24 h and the second largest sustained rain event during October. The movement we observed may have been due to disturbance from handling and marking, although this was minimized in the field.

Herpetological Review↗

USGS2019

Bats in a changing landscape: Linking occupancy and traits of a diverse montane bat community to fire regime

1. Wildfires are increasing in incidence and severity across the western US, leading to changes in forest structure and wildlife habitats. Knowledge of how species respond to fire-driven habitat changes in these landscapes is limited and generally disconnected from our understanding of adaptations that underpin responses to fire. 2. We aimed to identify relationships between fire regime, physiographic and forest structure variables, and occupancy and functional traits of a diverse bat community, to inform forest management in a fire-prone landscape. 3. We recorded bats acoustically at 83 sites (n = 249 recording nights) across the Plumas National Forest in the northern Sierra Nevada over 3 summers (2015-2017). We investigated relationships between fire regime, physiographic and forest structure and probability of bat occupancy for 9 species. We used fourth corner regression and RLQ analysis to identify ecomorphological traits (body mass; call frequency, bandwidth and duration; and open, edge or clutter (structurally complex vegetation) adapted foraging strategy) driving species-environment relationships across all 17 bat species. 4. Relationships between bat traits and fire regime were driven by adaptations to diverse forest structure. Bats adapted to foraging in open habitats and emitting longer duration and narrow bandwidth calls were associated with higher severity and more frequent fires, and bats adapted to foraging in a more cluttered environment were negatively associated with fire. Relationships between edge-adapted bat species and fire were driven by prey preference or habitat availability and configuration at a landscape scale. 5. Predicted increases in fire frequency and severity in the western US are likely to shift dominance in the bat community to species adapted to open environments and those able to exploit post-fire resource pulses (aquatic insects, beetles, snags). Managing for pyrodiversity within the western US is likely important for maintaining bat community diversity, as well as diversity of other biotic communities. Identifying trait-fire regime relationships will help forest managers develop appropriate management interventions and focus limited resources to provide for a broad range of species.

Ecology and Evolution↗