A suite of geophysical data obtained along the Richardson Highway crosses the eastern Alaska Range and Denali fault and reveals the crustal structure of the orogen. Strong seismic reflections from within the orogen north of the Denali fault dip as steeply as 25° north and extend downward to depths between 20 and 25 km. These reflections reveal what is probably a shear zone that transects most of the crust and is part of a crustal-scale duplex structure that probably formed during the Late Cretaceous. These structures, however, appear to be relict because over the past 20 years, they have produced little or no seismicity despite the nearby Mw = 7.9 Denali fault earthquake that struck in 2002. The Denali fault is nonreflective, but we interpret modeled magnetotelluric (MT), gravity, and magnetic data to propose that the fault dips steeply to vertically. Modeling of MT data shows that aftershocks of the 2002 Denali fault earthquake occurred above a rock body that has low electrical resistivity (>10 ohm-m), which might signify the presence of fluids in the middle and lower crust.
Several narrow terranes occur along the Denali fault in the Eastern and Central Alaska Range in Southern Alaska. These terranes are the Aurora Peak, Cottonwood Creek, Maclaren, Pingston, and Windy terranes, and a terrane of ultramafic and associated rocks. Exterior to the narrow terranes to the south is the major Wrangellia island arc composite terrane, and to the north is the major Yukon-Tanana metamorphosed continental margin terrane. Overlying mainly the northern margin of the Wrangellia composite terrane are the Kahiltna overlap assemblage to the west, and the Gravina-Nutzotin-Gambier volcanic-plutonic-sedimentary belt to the east and southeast. The various narrow terranes are interpreted as the result of translation of fragments of larger terranes during two major tectonic events: (1) Late Jurassic to mid-Cretaceous accretion of the Wrangellia island arc composite terrane (or superterrane composed of the Wrangellia, Peninsular, and Alexander terranes) and associated subduction zone complexes; and (2) starting in about the Late Cretaceous, dextral transport of the Wrangellia composite terrane along the Denali fault. These two major tectonic events caused: (1) entrapment of a lens of oceanic lithosphere along the suture belt between the Wrangellia composite terrane and the North American Craton Margin and outboard accreted terranes to form the ultramafic and mafic part of the terrane of ultra-mafic and associated rocks, (2) subsequent dextral translation along the Denali fault of the terrane of ultramafic and associated rocks, (3) dextral translation along the Denali fault of the Aurora Peak, Cottonwood Creek, and Maclaren and continental margin arc terranes from part of the Coast plutonic-metamorphic complex (Coast-North Cascade plutonic belt) in the southwest Yukon Territory or Southeastern Alaska, (4) dextral translation along the Denali fault of the Pingston passive continental margin from a locus along the North American Continental Margin, and (5) formation and dextral transport along the Denali fault of the mélange of the Windy terrane from fragments of the Gravina-Nutzotin-Gambier volcanic-plutonic-sedimentary belt and from the North American Continental Margin.
The lithosphere crack model, the main alternative to the mantle plume model for age-progressive magma emplacement along the Hawaiian-Emperor volcano chain, requires the maximum horizontal tensile stress to be normal to the volcano chain. However, published stress fields calculated from Pacific lithosphere tractions and body forces (e.g., subduction pull, basal drag, lithosphere density) are not optimal for southeast propagation of a stress-free, vertical tensile crack coincident with the Hawaiian segment of the Hawaiian-Emperor chain. Here we calculate the thermoelastic stress rate for present-day cooling of the Pacific plate using a spherical shell finite element representation of the plate geometry. We use observed seafloor isochrons and a standard model for lithosphere cooling to specify the time dependence of vertical temperature profiles. The calculated stress rate multiplied by a time increment (e.g., 1 m.y.) then gives a thermoelastic stress increment for the evolving Pacific plate. Near the Hawaiian chain position, the calculated stress increment in the lower part of the shell is tensional, with maximum tension normal to the chain direction. Near the projection of the chain trend to the southeast beyond Hawaii, the stress increment is compressive. This incremental stress field has the form necessary to maintain and propagate a tensile crack or similar lithosphere flaw and is thus consistent with the crack model for the Hawaiian volcano chain.
[1] A seismic reflection and refraction survey across the San Andreas Fault (SAF) near Parkfield provides a detailed characterization of crustal structure across the location of the San Andreas Fault Observatory at Depth (SAFOD). Steep-dip prestack migration and frequency domain acoustic waveform tomography were applied to obtain highly resolved images of the upper 5 km of the crust for 15 km on either side of the SAF. The resulting velocity model constrains the top of the Salinian granite with great detail. Steep-dip reflection seismic images show several strong-amplitude vertical reflectors in the uppermost crust near SAFOD that define an ∼2-km-wide zone comprising the main SAF and two or more local faults. Another prominent subvertical reflector at 2–4 km depth ∼9 km to the northeast of the SAF marks the boundary between the Franciscan terrane and the Great Valley Sequence. A deep seismic section of low resolution shows several reflectors in the Salinian crust west of the SAF. Two horizontal reflectors around 10 km depth correlate with strains of seismicity observed along-strike of the SAF. They represent midcrustal shear zones partially decoupling the ductile lower crust from the brittle upper crust. The deepest reflections from ∼25 km depth are interpreted as crust-mantle boundary.
We examine the impacts of a stand-clearing wildfire on the characteristics and magnitude of suspended sediment transport in ephemeral streams draining the burn area. We report the results of a monitoring program that includes 2 years of data prior to the Cerro Grande fire in New Mexico, and 3 years of postfire data. Suspended sediment concentration (SSC) increased by about 2 orders of magnitude following the fire, and the proportion of silt and clay increased from 50% to 80%. For a given flow event, SSC is highest at the flood bore and decreases monotonically with time, a pattern evident in every flood sampled both before and after the fire. We propose that the accumulation of flow and wash load at the flow front is an inherent characteristic of ephemeral stream flows, due to amplified momentum losses at the flood bore. We present a new model for computing suspended sediment transport in ephemeral streams (in the presence or absence of wildfire) by relating SSC to the time following the arrival of the flood bore, rather than to instantaneous discharge. Using this model and a rainfall history, we estimate that in the 3 years following the fire, floods transported in suspension a mass equivalent to about 3 mm of landscape lowering across the burn area, 20% of this following a single rainstorm. We test the model by computing fine sediment delivery to a small reservoir in an adjacent watershed, where we have a detailed record of postfire sedimentation based on repeat surveys. Systematic discrepancies between modeled and measured sedimentation rates in the reservoir suggest rapid reductions in suspended sediment delivery in the first several years after the fire.
The Saginaw Bay walleye population (Sander vitreus) has not fully recovered from a collapse that began in the 1940s and has been dependent on stocking with only limited natural reproduction. Beginning in 2003, and through at least 2005, reproductive success of walleye surged to unprecedented levels. The increase was concurrent with ecological changes in Lake Huron and we sought to quantitatively model which factors most influenced this new dynamic. We developed Ricker stock-recruitment models for both wild and stock fish and evaluated them with second-order Akaike's information criterion to find the best model. Independent variables included adult alewife (Alosa pseudoharengus) abundance, spring water temperatures, chlorophyll a levels and total phosphorus levels. In all, 14 models were evaluated for production of wild age-0 walleyes and eight models for stocked age-0 walleyes. For wild walleyes, adult alewife abundance was the dominant factor, accounting for 58% of the variability in age-0 abundance. Production of wild age-0 fish increased when adult alewives were scarce. The only other plausible factor was spring water temperature. Predictably, alewife abundance was not important to stocked fish; instead temperature and adult walleye abundance were more significant variables. The surge in reproductive success for walleyes during 2003–2005 was most likely due to large declines in adult alewives in Lake Huron. While relatively strong year classes (age-1 and up) have been produced as a result of increased age-0 production during 2003–2005, the overall magnitude has not been as great as the initial age-0 abundance originally suggested. It appears that over-winter mortality is higher than in the past and may stem from higher predation or slower growth (lower condition for enduring winter thermal stress). From this it appears that low alewife abundance does not assure strong walleye year classes in Saginaw Bay but may be a prerequisite for them.
","language":"English","publisher":"International Association for Great Lakes Research","doi":"10.3394/0380-1330(2007)33[118:EAECST]2.0.CO;2","issn":"03801330","usgsCitation":"Fielder, D., Schaeffer, J., and Thomas, M., 2007, Environmental and ecological conditions surrounding the production of large year classes of walleye (Sander vitreus) in Saginaw Bay, Lake Huron: Journal of Great Lakes Research, v. 33, no. Supplement 1, p. 118-132, https://doi.org/10.3394/0380-1330(2007)33[118:EAECST]2.0.CO;2.","productDescription":"15 p.","startPage":"118","endPage":"132","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[{"id":324,"text":"Great Lakes Science Center","active":true,"usgs":true}],"links":[{"id":240404,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":212850,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.3394/0380-1330(2007)33[118:EAECST]2.0.CO;2"}],"volume":"33","issue":"Supplement 1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a099be4b0c8380cd51fb4","contributors":{"authors":[{"text":"Fielder, D.G.","contributorId":22152,"corporation":false,"usgs":true,"family":"Fielder","given":"D.G.","email":"","affiliations":[],"preferred":false,"id":425740,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Schaeffer, J.S.","contributorId":42688,"corporation":false,"usgs":true,"family":"Schaeffer","given":"J.S.","email":"","affiliations":[],"preferred":false,"id":425741,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Thomas, M.V.","contributorId":66908,"corporation":false,"usgs":true,"family":"Thomas","given":"M.V.","email":"","affiliations":[],"preferred":false,"id":425742,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70030108,"text":"70030108 - 2007 - Eogenetic karst hydrology: Insights from the 2004 hurricanes, peninsular Florida","interactions":[],"lastModifiedDate":"2012-03-12T17:21:10","indexId":"70030108","displayToPublicDate":"2007-01-01T00:00:00","publicationYear":"2007","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1861,"text":"Ground Water","active":true,"publicationSubtype":{"id":10}},"title":"Eogenetic karst hydrology: Insights from the 2004 hurricanes, peninsular Florida","docAbstract":"Eogenetic karst lies geographically and temporally close to the depositional environment of limestone in warm marine water at low latitude, in areas marked by midafternoon thunderstorms during a summer rainy season. Spring hydrographs from such an environment in north-central Florida are characterized by smooth, months-long, seasonal maxima. The passage of Hurricanes Frances and Jeanne in September 2004 over three field locations shows how the eogenetic karst of the Upper Floridan Aquifer responds to unequivocal recharge events. Hydrographs at wells in the High Springs area, Rainbow Springs, and at Morris, Briar, and Bat Caves all responded promptly with a similar drawn-out rise to a maximum that extended long into the winter dry season. The timing indicates that the typical hydrograph of eogenetic karst is not the short-term fluctuations of springs in epigenic, telogenetic karst, or the smoothed response to all the summer thunderstorms, but rather the protracted response of the system to rainfall that exceeds a threshold. The similarity of cave and noncave hydrographs indicates distributed autogenic recharge and a free communication between secondary porosity and permeable matrix - both of which differ from the hydrology of epigenic, telogenetic karst. At Briar Cave, drip rates lagged behind the water table rise, suggesting that recharge was delivered by fractures, which control the cave's morphology. At High Springs, hydrographs at the Santa Fe River and a submerged conduit apparently connected to it show sharp maxima after the storms, unlike the other cave hydrographs. Our interpretation is that the caves, in general, are discontinuous. ?? 2007 National Ground Water Association.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Ground Water","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1111/j.1745-6584.2007.00309.x","issn":"0017467X","usgsCitation":"Florea, L., and Vacher, H.L., 2007, Eogenetic karst hydrology: Insights from the 2004 hurricanes, peninsular Florida: Ground Water, v. 45, no. 4, p. 439-446, https://doi.org/10.1111/j.1745-6584.2007.00309.x.","startPage":"439","endPage":"446","numberOfPages":"8","costCenters":[],"links":[{"id":212822,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1111/j.1745-6584.2007.00309.x"},{"id":240369,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"45","issue":"4","noUsgsAuthors":false,"publicationDate":"2007-03-23","publicationStatus":"PW","scienceBaseUri":"505a09fee4b0c8380cd52144","contributors":{"authors":[{"text":"Florea, L.J.","contributorId":22968,"corporation":false,"usgs":true,"family":"Florea","given":"L.J.","email":"","affiliations":[],"preferred":false,"id":425738,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Vacher, H. Leonard","contributorId":90529,"corporation":false,"usgs":false,"family":"Vacher","given":"H.","email":"","middleInitial":"Leonard","affiliations":[],"preferred":false,"id":425739,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70030107,"text":"70030107 - 2007 - Rapid plant diversity assessment using a pixel nested plot design: A case study in Beaver Meadows, Rocky Mountain National Park, Colorado, USA","interactions":[],"lastModifiedDate":"2012-03-12T17:21:10","indexId":"70030107","displayToPublicDate":"2007-01-01T00:00:00","publicationYear":"2007","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1399,"text":"Diversity and Distributions","active":true,"publicationSubtype":{"id":10}},"title":"Rapid plant diversity assessment using a pixel nested plot design: A case study in Beaver Meadows, Rocky Mountain National Park, Colorado, USA","docAbstract":"Geospatial statistical modelling and thematic maps have recently emerged as effective tools for the management of natural areas at the landscape scale. Traditional methods for the collection of field data pertaining to questions of landscape were developed without consideration for the parameters of these applications. We introduce an alternative field sampling design based on smaller unbiased random plot and subplot locations called the pixel nested plot (PNP). We demonstrate the applicability of the PNP design of 15 m x 15 m to assess patterns of plant diversity and species richness across the landscape at Rocky Mountain National Park (RMNP), Colorado, USA in a time (cost)-efficient manner for field data collection. Our results produced comparable results to a previous study in the Beaver Meadow study (BMS) area within RMNP, where there was a demonstrated focus of plant diversity. Our study used the smaller PNP sampling design for field data collection which could be linked to geospatial information data and could be used for landscape-scale analyses and assessment applications. In 2003, we established 61 PNP in the eastern region of RMNP. We present a comparison between this approach using a sub-sample of 19 PNP from this data set and 20 of Modified Whittaker nested plots (MWNP) of 20 m x 50 m that were collected in the BMS area. The PNP captured 266 unique plant species while the MWNP captured 275 unique species. Based on a comparison of PNP and MWNP in the Beaver Meadows area, RMNP, the PNP required less time and area sampled to achieve a similar number of species sampled. Using the PNP approach for data collection can facilitate the ecological monitoring of these vulnerable areas at the landscape scale in a time- and therefore cost-effective manner. ?? 2007 The Authors.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Diversity and Distributions","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1111/j.1472-4642.2007.00333.x","issn":"13669516","usgsCitation":"Kalkhan, M.A., Stafford, E., and Stohlgren, T., 2007, Rapid plant diversity assessment using a pixel nested plot design: A case study in Beaver Meadows, Rocky Mountain National Park, Colorado, USA: Diversity and Distributions, v. 13, no. 4, p. 379-388, https://doi.org/10.1111/j.1472-4642.2007.00333.x.","startPage":"379","endPage":"388","numberOfPages":"10","costCenters":[],"links":[{"id":212821,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1111/j.1472-4642.2007.00333.x"},{"id":240368,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"13","issue":"4","noUsgsAuthors":false,"publicationDate":"2007-03-19","publicationStatus":"PW","scienceBaseUri":"505a94f7e4b0c8380cd8171d","contributors":{"authors":[{"text":"Kalkhan, M. A.","contributorId":82655,"corporation":false,"usgs":false,"family":"Kalkhan","given":"M.","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":425737,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Stafford, E.J.","contributorId":11831,"corporation":false,"usgs":true,"family":"Stafford","given":"E.J.","email":"","affiliations":[],"preferred":false,"id":425736,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Stohlgren, T.J.","contributorId":7217,"corporation":false,"usgs":true,"family":"Stohlgren","given":"T.J.","email":"","affiliations":[],"preferred":false,"id":425735,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70030105,"text":"70030105 - 2007 - Species richness and soil properties in Pinus ponderosa forests: A structural equation modeling analysis","interactions":[],"lastModifiedDate":"2012-03-12T17:21:05","indexId":"70030105","displayToPublicDate":"2007-01-01T00:00:00","publicationYear":"2007","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2490,"text":"Journal of Vegetation Science","active":true,"publicationSubtype":{"id":10}},"title":"Species richness and soil properties in Pinus ponderosa forests: A structural equation modeling analysis","docAbstract":"Question: How are the effects of mineral soil properties on understory plant species richness propagated through a network of processes involving the forest overstory, soil organic matter, soil nitrogen, and understory plant abundance? Location: North-central Arizona, USA. Methods: We sampled 75 0.05-ha plots across a broad soil gradient in a Pinus ponderosa (ponderosa pine) forest ecosystem. We evaluated multivariate models of plant species richness using structural equation modeling. Results: Richness was highest at intermediate levels of understory plant cover, suggesting that both colonization success and competitive exclusion can limit richness in this system. We did not detect a reciprocal positive effect of richness on plant cover. Richness was strongly related to soil nitrogen in the model, with evidence for both a direct negative effect and an indirect non-linear relationship mediated through understory plant cover. Soil organic matter appeared to have a positive influence on understory richness that was independent of soil nitrogen. Richness was lowest where the forest overstory was densest, which can be explained through indirect effects on soil organic matter, soil nitrogen and understory cover. Finally, model results suggest a variety of direct and indirect processes whereby mineral soil properties can influence richness. Conclusions: Understory plant species richness and plant cover in P. ponderosa forests appear to be significantly influenced by soil organic matter and nitrogen, which are, in turn, related to overstory density and composition and mineral soil properties. Thus, soil properties can impose direct and indirect constraints on local species diversity in ponderosa pine forests. ?? IAVS; Opulus Press.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Journal of Vegetation Science","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1658/1100-9233(2007)18[231:SRASPI]2.0.CO;2","issn":"11009233","usgsCitation":"Laughlin, D., Abella, S., Covington, W., and Grace, J., 2007, Species richness and soil properties in Pinus ponderosa forests: A structural equation modeling analysis: Journal of Vegetation Science, v. 18, no. 2, p. 231-242, https://doi.org/10.1658/1100-9233(2007)18[231:SRASPI]2.0.CO;2.","startPage":"231","endPage":"242","numberOfPages":"12","costCenters":[],"links":[{"id":240298,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":212762,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1658/1100-9233(2007)18[231:SRASPI]2.0.CO;2"}],"volume":"18","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b950fe4b08c986b31ad13","contributors":{"authors":[{"text":"Laughlin, D.C.","contributorId":42407,"corporation":false,"usgs":true,"family":"Laughlin","given":"D.C.","email":"","affiliations":[],"preferred":false,"id":425729,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Abella, S.R.","contributorId":47982,"corporation":false,"usgs":true,"family":"Abella","given":"S.R.","affiliations":[],"preferred":false,"id":425730,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Covington, W.W.","contributorId":22151,"corporation":false,"usgs":true,"family":"Covington","given":"W.W.","email":"","affiliations":[],"preferred":false,"id":425727,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Grace, J.B. 0000-0001-6374-4726","orcid":"https://orcid.org/0000-0001-6374-4726","contributorId":38938,"corporation":false,"usgs":true,"family":"Grace","given":"J.B.","affiliations":[],"preferred":false,"id":425728,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70030104,"text":"70030104 - 2007 - Population-specific demographic estimates provide insights into declines of Lark Buntings (Calamospiza melanocorys)","interactions":[],"lastModifiedDate":"2017-05-08T13:03:26","indexId":"70030104","displayToPublicDate":"2007-01-01T00:00:00","publicationYear":"2007","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3544,"text":"The Auk","onlineIssn":"1938-4254","printIssn":"0004-8038","active":true,"publicationSubtype":{"id":10}},"title":"Population-specific demographic estimates provide insights into declines of Lark Buntings (Calamospiza melanocorys)","docAbstract":"Many North American prairie bird populations have recently declined, and the causes of these declines remain largely unknown. To determine whether population limitation occurs during breeding, we evaluated the stability of a population of prairie birds using population-specific values for fecundity and postfledging survival. During 2001-2003, we radiomarked 67 female Lark Buntings (Calamospiza melanocorys) to determine annual fecundity and evaluate contributing factors such as nest survival and breeding response (number of breeding attempts and dispersal). Collectively, 67 females built 112 nests (1.67 ± 0.07 nests female−1 season−1; range: 1–3); 34 were second nests and 11 were third nests. Daily nest survival estimates were similar for initial and later nests with overall nest survival (DSR19) of 30.7% and 31.7%, respectively. Nest predation was the most common cause of failure (92%). Capture and radiomarking of females did not affect nest survival. Lark Bunting dispersal probabilities increased among females that fledged young from initial nests and females that lost their original nests late in the season. Conservative and liberal estimates of mean annual fecundity were 0.96 ±0.11 and 1.24 ± 0.09 female offspring per female, respectively. Given the fecundity and juvenile-survival estimates for this population, annual adult survival values of 71–77% are necessary to achieve a stable population. Because adult survival of prairie passerines ranges between 55% and 65%, this study area may not be capable of sustaining a stable population in the absence of immigration. We contrast our population assessment with one that assumes indirect values of fecundity and juvenile survival. To elucidate limiting factors, estimation of population-specific demographic parameters is desirable. We present an approach for selecting species and areas for evaluation of population stability.
","language":"English","publisher":"American Ornithological Society","doi":"10.1642/0004-8038(2007)124[578:PDEPII]2.0.CO;2","issn":"00048038","usgsCitation":"Yackel Adams, A., Skagen, S., and Savidge, J.A., 2007, Population-specific demographic estimates provide insights into declines of Lark Buntings (Calamospiza melanocorys): The Auk, v. 124, no. 2, p. 578-593, https://doi.org/10.1642/0004-8038(2007)124[578:PDEPII]2.0.CO;2.","productDescription":"16 p.","startPage":"578","endPage":"593","costCenters":[],"links":[{"id":477211,"rank":1,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1642/0004-8038(2007)124[578:pdepii]2.0.co;2","text":"Publisher Index Page"},{"id":240297,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"124","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a7dc2e4b0c8380cd7a137","contributors":{"authors":[{"text":"Yackel Adams, A. A. 0000-0002-7044-8447","orcid":"https://orcid.org/0000-0002-7044-8447","contributorId":16792,"corporation":false,"usgs":true,"family":"Yackel Adams","given":"A. A.","affiliations":[],"preferred":false,"id":425724,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Skagen, S. K. 0000-0002-6744-1244","orcid":"https://orcid.org/0000-0002-6744-1244","contributorId":31348,"corporation":false,"usgs":true,"family":"Skagen","given":"S. K.","affiliations":[],"preferred":false,"id":425725,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Savidge, J. A.","contributorId":36078,"corporation":false,"usgs":false,"family":"Savidge","given":"J.","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":425726,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70030103,"text":"70030103 - 2007 - Lead (Pb) in old Antarctic ice: Some from dust, some from other sources","interactions":[],"lastModifiedDate":"2012-03-12T17:21:05","indexId":"70030103","displayToPublicDate":"2007-01-01T00:00:00","publicationYear":"2007","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1807,"text":"Geophysical Research Letters","active":true,"publicationSubtype":{"id":10}},"title":"Lead (Pb) in old Antarctic ice: Some from dust, some from other sources","docAbstract":"Recently published data on amounts and isotopic compositions of lead (Pb) and on amounts of mineral dust in pre-industrial Antarctic ice can be further interpreted by means of simple calculations. These show that two distinct types of Pb were provided by the atmosphere to the continent in varying proportions during Pleistocene and Holocene time. One type of Pb is that contained in the mineral lattices of dust. It has non-radiogenic isotopic proportions. The other type of Pb is not associated with dust minerals, is more radiogenic, and is consistent with an origin in emissions from ocean island volcanoes worldwide, or from some Antarctic volcanoes.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Geophysical Research Letters","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1029/2006GL028736","issn":"00948276","usgsCitation":"Hinkley, T., 2007, Lead (Pb) in old Antarctic ice: Some from dust, some from other sources: Geophysical Research Letters, v. 34, no. 8, https://doi.org/10.1029/2006GL028736.","costCenters":[],"links":[{"id":477113,"rank":10000,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1029/2006gl028736","text":"Publisher Index Page"},{"id":212760,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1029/2006GL028736"},{"id":240296,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"34","issue":"8","noUsgsAuthors":false,"publicationDate":"2007-04-28","publicationStatus":"PW","scienceBaseUri":"505a45a5e4b0c8380cd6745d","contributors":{"authors":[{"text":"Hinkley, T. 0000-0001-8507-6271","orcid":"https://orcid.org/0000-0001-8507-6271","contributorId":46690,"corporation":false,"usgs":true,"family":"Hinkley","given":"T.","affiliations":[],"preferred":false,"id":425723,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70030102,"text":"70030102 - 2007 - On the formation and structure of rare-earth element complexes in aqueous solutions under hydrothermal conditions with new data on gadolinium aqua and chloro complexes","interactions":[],"lastModifiedDate":"2012-03-12T17:21:06","indexId":"70030102","displayToPublicDate":"2007-01-01T00:00:00","publicationYear":"2007","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1213,"text":"Chemical Geology","active":true,"publicationSubtype":{"id":10}},"title":"On the formation and structure of rare-earth element complexes in aqueous solutions under hydrothermal conditions with new data on gadolinium aqua and chloro complexes","docAbstract":"Synchrotron X-ray spectroscopy experiments were made on the Gd(III) aqua and chloro complexes in low pH aqueous solutions at temperatures ranging from 25 to 500????C and at pressures up to 480??MPa using a hydrothermal diamond anvil cell. Analysis of fluorescence Gd L3-edge X-ray absorption fine structure (XAFS) spectra measured from a 0.006m Gd/0.16m HNO3 aqueous solution at temperatures up to 500????C and at pressures up to 260??MPa shows that the Gd-O distance of the Gd3+ aqua ion decreases steadily at a rate of ??? 0.007??A??/100????C whereas the number of coordinated H2O molecules decreases from 9.0 ?? 0.5 to 7.0 ?? 0.4. The loss of water molecules in the Gd3+ aqua ion inner hydration shell over this temperature range (a 22% reduction) is smaller than exhibited by the Yb3+ aqua ion (42% reduction) indicating that the former is significantly more stable than the later. We conjecture that the anomalous enrichment of Gd reported from measurement of REE concentrations in ocean waters may be attributed to the enhanced stability of the Gd3+ aqua ion relative to other REEs. Gd L3-edge XAFS measurements of 0.006m and 0.1m GdCl3 aqueous solutions at temperatures up to 500????C and pressures up to 480??MPa reveal that the onset of significant Gd3+-Cl- association occurs around 300????C. Partially-hydrated stepwise inner-sphere complexes most likely of the type Gd(H2O)??-nCln+3-n occur in the chloride solutions at higher temperatures, where ?? ??? 8 at 300????C decreasing slightly to an intermediate value between 7 and 8 upon approaching 500????C. This is the first direct evidence for the occurrence of partially-hydrated REE Gd (this study) and Yb [Mayanovic, R.A., Jayanetti, S., Anderson, A.J., Bassett, W.A., Chou, I-M., 2002a. The structure of Yb3+ aquo ion and chloro complexes in aqueous solutions at up to 500 ??C and 270 MPa. J. Phys. Chem. A 106, 6591-6599.] chloro complexes in hydrothermal solutions. The number of chlorides (n) of the partially-hydrated Gd(III) chloro complexes increases steadily with temperature from 0.4 ?? 0.2 to 1.7 ?? 0.3 in the 0.006m chloride solution and from 0.9 ?? 0.7 to 1.8 ?? 0.7 in the 0.1m GdCl3 aqueous solution in the 300-500????C range. Conversely, the number of H2O ligands of Gd(H2O)??-nCln+3-n complexes decreases steadily from 8.9 ?? 0.4 to 5.8 ?? 0.7 in the 0.006m GdCl3 aqueous solution and from 9.0 ?? 0.5 to 5.3 ?? 1.0 in the 0.1m GdCl3 aqueous solution at temperatures from 25 to 500????C. Analysis of our results shows that the chloride ions partially displace the inner-shell water molecules during Gd(III) complex formation under hydrothermal conditions. The Gd-OH2 bond of the partially-hydrated Gd(III) chloro complexes exhibits slightly smaller rates of length contraction (??? 0.005??A??/100????C) for both solutions. The structural aspects of chloride speciation of Gd(III) as measured from this study and of Yb(III) as measured from our previous experiments are consistent with the solubility of these and other REE in deep-sea hydrothermal fluids. ?? 2006 Elsevier B.V. All rights reserved.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Chemical Geology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/j.chemgeo.2006.10.004","issn":"00092541","usgsCitation":"Mayanovic, R.A., Anderson, A.J., Bassett, W.A., and Chou, I., 2007, On the formation and structure of rare-earth element complexes in aqueous solutions under hydrothermal conditions with new data on gadolinium aqua and chloro complexes: Chemical Geology, v. 239, no. 3-4, p. 266-283, https://doi.org/10.1016/j.chemgeo.2006.10.004.","startPage":"266","endPage":"283","numberOfPages":"18","costCenters":[],"links":[{"id":212729,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/j.chemgeo.2006.10.004"},{"id":240261,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"239","issue":"3-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a6dcce4b0c8380cd75330","contributors":{"authors":[{"text":"Mayanovic, Robert A.","contributorId":88528,"corporation":false,"usgs":true,"family":"Mayanovic","given":"Robert","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":425722,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Anderson, Alan J.","contributorId":28770,"corporation":false,"usgs":true,"family":"Anderson","given":"Alan","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":425719,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Bassett, William A.","contributorId":47533,"corporation":false,"usgs":true,"family":"Bassett","given":"William","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":425721,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Chou, I.-M. 0000-0001-5233-6479","orcid":"https://orcid.org/0000-0001-5233-6479","contributorId":44283,"corporation":false,"usgs":true,"family":"Chou","given":"I.-M.","affiliations":[{"id":245,"text":"Eastern Mineral and Environmental Resources Science Center","active":true,"usgs":true}],"preferred":false,"id":425720,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70030100,"text":"70030100 - 2007 - Improved wetland remote sensing in Yellowstone National Park using classification trees to combine TM imagery and ancillary environmental data","interactions":[],"lastModifiedDate":"2018-02-21T11:28:14","indexId":"70030100","displayToPublicDate":"2007-01-01T00:00:00","publicationYear":"2007","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3254,"text":"Remote Sensing of Environment","printIssn":"0034-4257","active":true,"publicationSubtype":{"id":10}},"title":"Improved wetland remote sensing in Yellowstone National Park using classification trees to combine TM imagery and ancillary environmental data","docAbstract":"The U.S. Fish and Wildlife Service uses the term palustrine wetland to describe vegetated wetlands traditionally identified as marsh, bog, fen, swamp, or wet meadow. Landsat TM imagery was combined with image texture and ancillary environmental data to model probabilities of palustrine wetland occurrence in Yellowstone National Park using classification trees. Model training and test locations were identified from National Wetlands Inventory maps, and classification trees were built for seven years spanning a range of annual precipitation. At a coarse level, palustrine wetland was separated from upland. At a finer level, five palustrine wetland types were discriminated: aquatic bed (PAB), emergent (PEM), forested (PFO), scrub–shrub (PSS), and unconsolidated shore (PUS). TM-derived variables alone were relatively accurate at separating wetland from upland, but model error rates dropped incrementally as image texture, DEM-derived terrain variables, and other ancillary GIS layers were added. For classification trees making use of all available predictors, average overall test error rates were 7.8% for palustrine wetland/upland models and 17.0% for palustrine wetland type models, with consistent accuracies across years. However, models were prone to wetland over-prediction. While the predominant PEM class was classified with omission and commission error rates less than 14%, we had difficulty identifying the PAB and PSS classes. Ancillary vegetation information greatly improved PSS classification and moderately improved PFO discrimination. Association with geothermal areas distinguished PUS wetlands. Wetland over-prediction was exacerbated by class imbalance in likely combination with spatial and spectral limitations of the TM sensor. Wetland probability surfaces may be more informative than hard classification, and appear to respond to climate-driven wetland variability. The developed method is portable, relatively easy to implement, and should be applicable in other settings and over larger extents.
","language":"English","publisher":"Elsevier","doi":"10.1016/j.rse.2006.10.019","issn":"00344257","usgsCitation":"Wright, C., and Gallant, A.L., 2007, Improved wetland remote sensing in Yellowstone National Park using classification trees to combine TM imagery and ancillary environmental data: Remote Sensing of Environment, v. 107, no. 4, p. 582-605, https://doi.org/10.1016/j.rse.2006.10.019.","productDescription":"24 p.","startPage":"582","endPage":"605","numberOfPages":"24","costCenters":[{"id":222,"text":"Earth Resources Observation and Science (EROS) Center","active":true,"usgs":true}],"links":[{"id":240226,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":212700,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/j.rse.2006.10.019"}],"volume":"107","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a3968e4b0c8380cd618f2","contributors":{"authors":[{"text":"Wright, C.","contributorId":69589,"corporation":false,"usgs":true,"family":"Wright","given":"C.","affiliations":[],"preferred":false,"id":425715,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Gallant, Alisa L. 0000-0002-3029-6637 gallant@usgs.gov","orcid":"https://orcid.org/0000-0002-3029-6637","contributorId":2940,"corporation":false,"usgs":true,"family":"Gallant","given":"Alisa","email":"gallant@usgs.gov","middleInitial":"L.","affiliations":[{"id":223,"text":"Earth Resources Observation and Science (EROS) Center (Geography)","active":false,"usgs":true},{"id":222,"text":"Earth Resources Observation and Science (EROS) Center","active":true,"usgs":true}],"preferred":true,"id":425716,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70030099,"text":"70030099 - 2007 - Mangrove removal in the belize cays: effects on mangrove-associated fish assemblages in the intertidal and subtidal","interactions":[],"lastModifiedDate":"2014-10-07T13:42:47","indexId":"70030099","displayToPublicDate":"2007-01-01T00:00:00","publicationYear":"2007","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1106,"text":"Bulletin of Marine Science","active":true,"publicationSubtype":{"id":10}},"title":"Mangrove removal in the belize cays: effects on mangrove-associated fish assemblages in the intertidal and subtidal","docAbstract":"We investigated the effects of mangrove cutting on fish assemblages in Twin Cays, Belize, in two habitat types. We conducted visual censuses at two sites in adjoining undisturbed/disturbed (30%–70% of shoreline fringe removed) sub-tidal fringing Rhizophora mangle Linnaeus, 1753. Observers recorded significantly more species and individuals in undisturbed sites, especially among smaller, schooling species (e.g., atherinids, clupeids), where densities were up to 200 times greater in undisturbed habitat. Multivariate analyses showed distinct species assemblages between habitats at both sites. In addition, extensive trapping with wire minnow traps within the intertidal zone in both undisturbed and disturbed fringing and transition (landward) mangrove forests was conducted. Catch rates were low: 638 individuals from 24 species over 563 trap-nights. Trap data, however, indicated that mangrove disturbance had minimal effect on species composition in either forest type (fringe/transition). Different results from the two methods (and habitat types) may be explained by two factors: (1) a larger and more detectable species pool in the subtidal habitat, with visual \"access\" to all species, and (2) the selective nature of trapping. Our data indicate that even partial clearing of shoreline and more landward mangroves can have a significant impact on local fish assemblages.","largerWorkTitle":"Bulletin of Marine Science","language":"English","publisher":"University of Miami - Rosenstiel School of Marine and Atmospheric Science","issn":"00074977","usgsCitation":"Taylor, D., Reyier, E., Davis, W., and McIvor, C., 2007, Mangrove removal in the belize cays: effects on mangrove-associated fish assemblages in the intertidal and subtidal: Bulletin of Marine Science, v. 80, no. 3, p. 879-890.","productDescription":"12 p.","startPage":"879","endPage":"890","numberOfPages":"12","costCenters":[{"id":186,"text":"Coastal and Marine Geology Program","active":true,"usgs":true}],"links":[{"id":240225,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":295033,"type":{"id":15,"text":"Index Page"},"url":"https://www.ingentaconnect.com/search/article?option1=tka&value1=Mangrove+removal+in+the+belize+cays%3a+Effects+on+mangrove-associated+fish+assemblages+in+the+intertidal+and+subtidal&pageSize=10&index=1"}],"country":"Belize","otherGeospatial":"Twin Cays","volume":"80","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a4ccce4b0c8380cd69ec9","contributors":{"authors":[{"text":"Taylor, D.S.","contributorId":17835,"corporation":false,"usgs":true,"family":"Taylor","given":"D.S.","email":"","affiliations":[],"preferred":false,"id":425711,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Reyier, E.A.","contributorId":84564,"corporation":false,"usgs":true,"family":"Reyier","given":"E.A.","affiliations":[],"preferred":false,"id":425714,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Davis, W.P.","contributorId":64893,"corporation":false,"usgs":true,"family":"Davis","given":"W.P.","email":"","affiliations":[],"preferred":false,"id":425713,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"McIvor, C.C.","contributorId":38104,"corporation":false,"usgs":true,"family":"McIvor","given":"C.C.","email":"","affiliations":[],"preferred":false,"id":425712,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70030098,"text":"70030098 - 2007 - Temperature-mediated differences in bacterial kidney disease expression and survival in Renibacterium salmoninarum-challenged bull trout and other salmonids","interactions":[],"lastModifiedDate":"2012-03-12T17:21:06","indexId":"70030098","displayToPublicDate":"2007-01-01T00:00:00","publicationYear":"2007","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2886,"text":"North American Journal of Fisheries Management","active":true,"publicationSubtype":{"id":10}},"title":"Temperature-mediated differences in bacterial kidney disease expression and survival in Renibacterium salmoninarum-challenged bull trout and other salmonids","docAbstract":"Resource managers considering restoration and reconnection of watersheds to protect and enhance threatened populations of bull trout Salvelinus confluentus have little information about the consequences of bacterial kidney disease (BKD) caused by Renibacterium salmoninarum. To better understand the response of bull trout to R. salmoninarum challenge, we conducted several laboratory experiments at two water temperatures. The extent, severity, and lethality of BKD in bull trout were compared with those of similarly challenged lake trout S. namaycush, Arctic char S. alpinus, Chinook salmon Oncorhynchus tshawytscha, and rainbow trout O. mykiss. The lethal dose of bacterial cells necessary to induce 50% mortality (LD50) was 10-fold lower at the 15??C challenge than at the 9??C challenge. Of the species tested, bull trout were relatively resistant to BKD, Arctic char were the most susceptible among Salvelinus species, and Chinook salmon were the most susceptible among Oncorhynchus species tested. Mean time to death was more rapid for all fish tested at 15??C than for fish challenged at 9??C. These results suggest that infection of bull trout with BKD likely poses a low risk to successful restoration of threatened populations. ?? Copyright by the American Fisheries Society 2007.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"North American Journal of Fisheries Management","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1577/M06-002.1","issn":"02755947","usgsCitation":"Jones, D., Moffitt, C., and Peters, K., 2007, Temperature-mediated differences in bacterial kidney disease expression and survival in Renibacterium salmoninarum-challenged bull trout and other salmonids: North American Journal of Fisheries Management, v. 27, no. 2, p. 695-706, https://doi.org/10.1577/M06-002.1.","startPage":"695","endPage":"706","numberOfPages":"12","costCenters":[],"links":[{"id":212671,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1577/M06-002.1"},{"id":240194,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"27","issue":"2","noUsgsAuthors":false,"publicationDate":"2007-05-01","publicationStatus":"PW","scienceBaseUri":"505ba4d6e4b08c986b320607","contributors":{"authors":[{"text":"Jones, D.T.","contributorId":35024,"corporation":false,"usgs":true,"family":"Jones","given":"D.T.","email":"","affiliations":[],"preferred":false,"id":425708,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Moffitt, C.M.","contributorId":84554,"corporation":false,"usgs":true,"family":"Moffitt","given":"C.M.","email":"","affiliations":[],"preferred":false,"id":425710,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Peters, K.K.","contributorId":62025,"corporation":false,"usgs":true,"family":"Peters","given":"K.K.","email":"","affiliations":[],"preferred":false,"id":425709,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70030097,"text":"70030097 - 2007 - Effects of management and climate on elk brucellosis in the Greater Yellowstone Ecosystem","interactions":[],"lastModifiedDate":"2019-12-04T06:34:15","indexId":"70030097","displayToPublicDate":"2007-01-01T00:00:00","publicationYear":"2007","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1450,"text":"Ecological Applications","active":true,"publicationSubtype":{"id":10}},"title":"Effects of management and climate on elk brucellosis in the Greater Yellowstone Ecosystem","docAbstract":"Every winter, government agencies feed ∼6000 metric tons (6 × 106 kg) of hay to elk in the southern Greater Yellowstone Ecosystem (GYE) to limit transmission of Brucella abortus, the causative agent of brucellosis, from elk to cattle. Supplemental feeding, however, is likely to increase the transmission of brucellosis in elk, and may be affected by climatic factors, such as snowpack. We assessed these possibilities using snowpack and feeding data from 1952 to 2006 and disease testing data from 1993 to 2006. Brucellosis seroprevalence was strongly correlated with the timing of the feeding season. Longer feeding seasons were associated with higher seroprevalence, but elk population size and density had only minor effects. In other words, the duration of host aggregation and whether it coincided with peak transmission periods was more important than just the host population size. Accurate modeling of disease transmission depends upon incorporating information on how host contact rates fluctuate over time relative to peak transmission periods. We also found that supplemental feeding seasons lasted longer during years with deeper snowpack. Therefore, milder winters and/or management strategies that reduce the length of the feeding season may reduce the seroprevalence of brucellosis in the elk populations of the southern GYE.
Canopy and surface fuels in many fire-prone forests of the United States have increased over the last 70 years as a result of modern fire exclusion policies, grazing, and other land management activities. The Healthy Forest Restoration Act and National Fire Plan establish a national commitment to reduce fire hazard and restore fire-adapted ecosystems across the USA. The primary index used to prioritize treatment areas across the nation is Fire Regime Condition Class (FRCC) computed as departures of current conditions from the historical fire and landscape conditions. This paper describes a process that uses an extensive set of ecological models to map FRCC from a departure statistic computed from simulated time series of historical landscape composition. This mapping process uses a data-driven, biophysical approach where georeferenced field data, biogeochemical simulation models, and spatial data libraries are integrated using spatial statistical modeling to map environmental gradients that are then used to predict vegetation and fuels characteristics over space. These characteristics are then fed into a landscape fire and succession simulation model to simulate a time series of historical landscape compositions that are then compared to the composition of current landscapes to compute departure, and the FRCC values. Intermediate products from this process are then used to create ancillary vegetation, fuels, and fire regime layers that are useful in the eventual planning and implementation of fuel and restoration treatments at local scales. The complex integration of varied ecological models at different scales is described and problems encountered during the implementation of this process in the LANDFIRE prototype project are addressed.
","language":"English","publisher":"Elsevier","doi":"10.1016/j.ecolmodel.2007.02.005","issn":"03043800","usgsCitation":"Keane, R.E., Rollins, M., and Zhu, Z., 2007, Using simulated historical time series to prioritize fuel treatments on landscapes across the United States: The LANDFIRE prototype project: Ecological Modelling, v. 204, no. 3-4, p. 485-502, https://doi.org/10.1016/j.ecolmodel.2007.02.005.","productDescription":"18 p.","startPage":"485","endPage":"502","numberOfPages":"18","costCenters":[{"id":222,"text":"Earth Resources Observation and Science (EROS) Center","active":true,"usgs":true}],"links":[{"id":213105,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/j.ecolmodel.2007.02.005"},{"id":240696,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"204","issue":"3-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bc0a0e4b08c986b32a229","contributors":{"authors":[{"text":"Keane, Robert E.","contributorId":73930,"corporation":false,"usgs":true,"family":"Keane","given":"Robert","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":425694,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Rollins, Matthew","contributorId":72347,"corporation":false,"usgs":true,"family":"Rollins","given":"Matthew","affiliations":[],"preferred":false,"id":425695,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Zhu, Zhi-Liang zzhu@usgs.gov","contributorId":3636,"corporation":false,"usgs":true,"family":"Zhu","given":"Zhi-Liang","email":"zzhu@usgs.gov","affiliations":[{"id":223,"text":"Earth Resources Observation and Science (EROS) Center (Geography)","active":false,"usgs":true}],"preferred":false,"id":425696,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70030092,"text":"70030092 - 2007 - Using biodynamic models to reconcile differences between laboratory toxicity tests and field biomonitoring with aquatic insects","interactions":[],"lastModifiedDate":"2023-08-02T11:28:20.798894","indexId":"70030092","displayToPublicDate":"2007-01-01T00:00:00","publicationYear":"2007","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1565,"text":"Environmental Science & Technology","onlineIssn":"1520-5851","printIssn":"0013-936X","active":true,"publicationSubtype":{"id":10}},"title":"Using biodynamic models to reconcile differences between laboratory toxicity tests and field biomonitoring with aquatic insects","docAbstract":"Aquatic insects often dominate lotic ecosystems, yet these organisms are under-represented in trace metal toxicity databases. Furthermore, toxicity data for aquatic insects do not appear to reflect their actual sensitivities to metals in nature, because the concentrations required to elicit toxicity in the laboratory are considerably higher than those found to impact insect communities in the field. New approaches are therefore needed to better understand how and why insects are differentially susceptible to metal exposures. Biodynamic modeling is a powerful tool for understanding interspecific differences in trace metal bioaccumulation. Because bioaccumulation alone does not necessarily correlate with toxicity, we combined biokinetic parameters associated with dissolved cadmium exposures with studies of the subcellular compartmentalization of accumulated Cd. This combination of physiological traits allowed us to make predictions of susceptibility differences to dissolved Cd in three aquatic insect taxa: Ephemerella excrucians, Rhithrogena morrisoni, and Rhyacophila sp. We compared these predictions with long-term field monitoring data and toxicity tests with closely related taxa: Ephemerella infrequens, Rhithrogena hageni, and Rhyacophila brunea. Kinetic parameters allowed us to estimate steady-state concentrations, the time required to reach steady state, and the concentrations of Cd projected to be in potentially toxic compartments for different species. Species-specific physiological traits identified using biodynamic models provided a means for better understanding why toxicity assays with insects have failed to provide meaningful estimates for metal concentrations that would be expected to be protective in nature.
A new approach has been developed for solving solute transport problems in randomly heterogeneous media using the Karhunen‐Loève‐based moment equation (KLME) technique proposed by Zhang and Lu (2004). The KLME approach combines the Karhunen‐Loève decomposition of the underlying random conductivity field and the perturbative and polynomial expansions of dependent variables including the hydraulic head, flow velocity, dispersion coefficient, and solute concentration. The equations obtained in this approach are sequential, and their structure is formulated in the same form as the original governing equations such that any existing simulator, such as Modular Three‐Dimensional Multispecies Transport Model for Simulation of Advection, Dispersion, and Chemical Reactions of Contaminants in Groundwater Systems (MT3DMS), can be directly applied as the solver. Through a series of two‐dimensional examples, the validity of the KLME approach is evaluated against the classical Monte Carlo simulations. Results indicate that under the flow and transport conditions examined in this work, the KLME approach provides an accurate representation of the mean concentration. For the concentration variance, the accuracy of the KLME approach is good when the conductivity variance is 0.5. As the conductivity variance increases up to 1.0, the mismatch on the concentration variance becomes large, although the mean concentration can still be accurately reproduced by the KLME approach. Our results also indicate that when the conductivity variance is relatively large, neglecting the effects of the cross terms between velocity fluctuations and local dispersivities, as done in some previous studies, can produce noticeable errors, and a rigorous treatment of the dispersion terms becomes more appropriate.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/2006WR005193","usgsCitation":"Liu, G., Lu, Z., and Zhang, D., 2007, Stochastic uncertainty analysis for solute transport in randomly heterogeneous media using a Karhunen‐Loève‐based moment equation approach: Water Resources Research, v. 43, no. 7, Article W07427; 15 p., https://doi.org/10.1029/2006WR005193.","productDescription":"Article W07427; 15 p.","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[],"links":[{"id":477023,"rank":1,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1029/2006wr005193","text":"Publisher Index Page"},{"id":240630,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"43","issue":"7","noUsgsAuthors":false,"publicationDate":"2007-07-18","publicationStatus":"PW","scienceBaseUri":"505b9853e4b08c986b31bf99","contributors":{"authors":[{"text":"Liu, Gaisheng","contributorId":15158,"corporation":false,"usgs":true,"family":"Liu","given":"Gaisheng","email":"","affiliations":[],"preferred":false,"id":425666,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Lu, Zhiming","contributorId":174148,"corporation":false,"usgs":false,"family":"Lu","given":"Zhiming","email":"","affiliations":[],"preferred":false,"id":425668,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Zhang, Dongxiao","contributorId":26409,"corporation":false,"usgs":true,"family":"Zhang","given":"Dongxiao","email":"","affiliations":[],"preferred":false,"id":425667,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ]}