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At least 343 records · Page 19Linked to original sources
USGS1959

Conodonts from the Chappel limestone of Texas

The Chappel limestone of Early Mississippian (late Kinderhook and probably partly early Osage) age crops out in the Llano region of Texas where it is as much as 45 feet thick. It contains three conodont faunal zones which, from youngest to oldest, are herein designated: (1) the Bactrognathus communis zone of probable early Osage age; (2) the Gnathodus punctatus zone of late Kinderhook (Chouteau) age—this zone ranges throughout the greater thickness of the Chappel; and (3) the Siphonodella cooperi zone, also of late Kinderhook (Chouteau) age. This zonation is based on an examination of the disjunct conodonts in more than 150 collections, as well as on a study of the frequency distribution of species in 68 collections. These 68 collections contain 22,946 identifiable specimens, some representing reworked material derived from Ordovician, Devonian, and lower-most Mississippian sources. Four generic names, Dollymae , Branmehla , Hindeodina , and Pandorinellina , are new; the last named replaces Pandorina Stauffer, 1940, which is preoccupied. A new classification of disjunct conodonts is presented. This classification, utilitarian rather than biologic, is based on the fact that each individual conodont was built up by the accretion of lamellae about the apex of the pulp cavity. This cavity is used as the point of reference for all other parts of the conodont structure. Separation of the lamellae from one another, along one or more growth axes and in one or more directions, resulted in the development of fanglike structures without dentides (Distacodontidae); fanglike structures with denticles (Belodontidae); denticulated blades and bars (Coleodontidae, Prioniodinidae, and Prioniodontidae); platelike structures with platforms (Polygnathidae); and platelike structures with greatly expanded pulp cavities (Idiognathodontidae).

Texas↗
USGS2004

Ground-water flow direction, water quality, recharge sources, and age, Great Sand Dunes National Monument, south-central Colorado

Great Sand Dunes National Monument is located in south-central Colorado along the eastern edge of the San Luis Valley. The Great Sand Dunes National Monument contains the tallest sand dunes in North America; some rise up to750 feet. Important ecological features of the Great Sand Dunes National Monument are palustrine wetlands associated with interdunal ponds and depressions along the western edge of the dune field. The existence and natural maintenance of the dune field and the interdunal ponds are dependent on maintaining ground-water levels at historic elevations. To address these concerns, the U.S. Geological Survey conducted a study, in collaboration with the National Park Service, of ground-water flow direction, water quality, recharge sources, and age at the Great Sand Dunes National Monument. A shallow unconfined aquifer and a deeper confined aquifer are the two principal aquifers at the Great Sand Dunes National Monument. Ground water in the unconfined aquifer is recharged from Medano and Sand Creeks near the Sangre de Cristo Mountain front, flows underneath the main dune field, and discharges to Big and Little Spring Creeks. The percentage of calcium in ground water in the unconfined aquifer decreases and the percentage of sodium increases because of ionic exchange with clay minerals as the ground water flows underneath the dune field. It takes more than 60 years for the ground water to flow from Medano and Sand Creeks to Big and Little Spring Creeks. During this time, ground water in the upper part of the unconfined aquifer is recharged by numerous precipitation events. Evaporation of precipitation during recharge prior to reaching the water table causes enrichment in deuterium (2H) and oxygen-18 (18O) relative to waters that are not evaporated. This recharge from precipitation events causes the apparent ages determined using chlorofluorocarbons and tritium to become younger, because relatively young precipitation water is mixing with older waters derived from Medano and Sand Creeks. Major ion chemistry of water from sites completed in the confined aquifer is different than water from sites completed in the unconfined aquifer, but insufficient data exist to quantify if the two aquifers are hydrologically disconnected. Radiocarbon dating of ground water in the confined aquifer indicates it is about 30,000 years old (plus or minus 3,000 years). The peak of the last major ice advance (Wisconsin) during the ice age occurred about 20,000 years before present; ground water from the confined aquifer is much older than that. Water quality and water levels of the interdunal ponds are not affected by waters from the confined aquifer. Instead, the interdunal ponds are affected directly by fluctuations in the water table of the unconfined aquifer. Any lowering of the water table of the unconfined aquifer would result in an immediate decrease in water levels of the interdunal ponds. The water quality of the interdunal ponds probably results from several factors, including the water quality of the unconfined aquifer, evaporation of the pond water, and biologic activity within the ponds.

Colorado↗
USGS2017

Comparison of oyster populations, shoreline protection service, and site characteristics at seven created fringing reefs in Louisiana: Key parameters and responses to consider

Coastal erosion threatens many low-lying areas around the globe. Rising sea levels from climate change are expected to increase coastal erosion and exacerbate flooding and storm surges. This is particularly true in low-lying coastal Louisiana, which developed as the Mississippi River changed course (delta switching) over the past 7000 years. Periods of land loss and gain resulted in an intricate coastal environment composed of shallow water areas with wetlands, swamps, barrier islands, and ridges (Day et al. 2007). This complex habitat sustains high economic and biological productivity, supporting the largest commercial fishery in the lower 48 states, providing habitat for important species of fish and wildlife, mitigating storm surge, and delivering protection for oil and gas production facilities, including five of the nation’s largest ports. Because of past and ongoing geological and physical processes, such as subsidence, sea level rise, tropical cyclonic activity, and direct human activities (Barras 2009; Chmura et al. 1992; Georgiou et al. 2005), coastal Louisiana is estimated to have lost an area almost the size of Delaware (4877 km2) between 1932 and 2010, with recent analyses indicating losses averaging 42.9 km2/year (Couvillion et al. 2011).

Book chapter↗
USGS2012

Determination of steroid hormones and related compounds in filtered and unfiltered water by solid-phase extraction, derivatization, and gas chromatography with tandem mass spectrometry

A new analytical method has been developed and implemented at the U.S. Geological Survey National Water Quality Laboratory that determines a suite of 20 steroid hormones and related compounds in filtered water (using laboratory schedule 2434) and in unfiltered water (using laboratory schedule 4434). This report documents the procedures and initial performance data for the method and provides guidance on application of the method and considerations of data quality in relation to data interpretation. The analytical method determines 6 natural and 3 synthetic estrogen compounds, 6 natural androgens, 1 natural and 1 synthetic progestin compound, and 2 sterols: cholesterol and 3--coprostanol. These two sterols have limited biological activity but typically are abundant in wastewater effluents and serve as useful tracers. Bisphenol A, an industrial chemical used primarily to produce polycarbonate plastic and epoxy resins and that has been shown to have estrogenic activity, also is determined by the method. A technique referred to as isotope-dilution quantification is used to improve quantitative accuracy by accounting for sample-specific procedural losses in the determined analyte concentration. Briefly, deuterium- or carbon-13-labeled isotope-dilution standards (IDSs), all of which are direct or chemically similar isotopic analogs of the method analytes, are added to all environmental and quality-control and quality-assurance samples before extraction. Method analytes and IDS compounds are isolated from filtered or unfiltered water by solid-phase extraction onto an octadecylsilyl disk, overlain with a graded glass-fiber filter to facilitate extraction of unfiltered sample matrices. The disks are eluted with methanol, and the extract is evaporated to dryness, reconstituted in solvent, passed through a Florisil solid-phase extraction column to remove polar organic interferences, and again evaporated to dryness in a reaction vial. The method compounds are reacted with activated -methyl--trimethylsilyl trifluoroacetamide at 65 degrees Celsius for 1 hour to form trimethylsilyl or trimethylsilyl-enol ether derivatives that are more amenable to gas chromatographic separation than the underivatized compounds. Analysis is carried out by gas chromatography with tandem mass spectrometry using calibration standards that are derivatized concurrently with the sample extracts. Analyte concentrations are quantified relative to specific IDS compounds in the sample, which directly compensate for procedural losses (incomplete recovery) in the determined and reported analyte concentrations. Thus, reported analyte concentrations (or analyte recoveries for spiked samples) are corrected based on recovery of the corresponding IDS compound during the quantification process. Recovery for each IDS compound is reported for each sample and represents an absolute recovery in a manner comparable to surrogate recoveries for other organic methods used by the National Water Quality Laboratory. Thus, IDS recoveries provide a useful tool for evaluating sample-specific analytical performance from an absolute mass recovery standpoint. IDS absolute recovery will differ and typically be lower than the corresponding analyte’s method recovery in spiked samples. However, additional correction of reported analyte concentrations is unnecessary and inappropriate because the analyte concentration (or recovery) already is compensated for by the isotope-dilution quantification procedure. Method analytes were spiked at 10 and 100 nanograms per liter (ng/L) for most analytes (10 times greater spike levels were used for bisphenol A and 100 times greater spike levels were used for 3--coprostanol and cholesterol) into the following validation-sample matrices: reagent water, wastewater-affected surface water, a secondary-treated wastewater effluent, and a primary (no biological treatment) wastewater effluent. Overall method recovery for all analytes in these matrices averaged 100 percent, with overall relative standard deviation of 28 percent. Mean recoveries of the 20 individual analytes for spiked reagent-water samples prepared along with field samples and analyzed in 2009–2010 ranged from 84–104 percent, with relative standard deviations of 6–36 percent. Concentrations for two analytes, equilin and progesterone, are reported as estimated because these analytes had excessive bias or variability, or both. Additional database coding is applied to other reported analyte data as needed, based on sample-specific IDS recovery performance. Detection levels were derived statistically by fortifying reagent water at six different levels (0.1 to 4 ng/L) and range from about 0.4 to 4 ng/L for 16 analytes. Interim reporting levels applied to analytes in this report range from 0.8 to 8 ng/L. Bisphenol A and the sterols (cholesterol and 3-beta-coprostanol) were consistently detected in laboratory and field blanks. The minimum reporting levels were set at 100 ng/L for bisphenol A and at 200 ng/L for the two sterols to prevent any bias associated with the presence of these compounds in the blanks. A minimum reporting level of 2 ng/L was set for 11-ketotestosterone to minimize false positive risk from an interfering siloxane compound emanating as chromatographic-column bleed, from vial septum material, or from other sources at no more than 1 ng/L.

Techniques and Methods↗
USGS2016

Transcriptome discovery in non-model wild fish species for the development of quantitative transcript abundance assays

Environmental studies increasingly identify the presence of both contaminants of emerging concern (CECs) and legacy contaminants in aquatic environments; however, the biological effects of these compounds on resident fishes remain largely unknown. High throughput methodologies were employed to establish partial transcriptomes for three wild-caught, non-model fish species; smallmouth bass ( Micropterus dolomieu ), white sucker ( Catostomus commersonii ) and brown bullhead ( Ameiurus nebulosus ). Sequences from these transcriptome databases were utilized in the development of a custom nCounter CodeSet that allowed for direct multiplexed measurement of 50 transcript abundance endpoints in liver tissue. Sequence information was also utilized in the development of quantitative real-time PCR (qPCR) primers. Cross-species hybridization allowed the smallmouth bass nCounter CodeSet to be used for quantitative transcript abundance analysis of an additional non-model species, largemouth bass ( Micropterus salmoides ). We validated the nCounter analysis data system with qPCR for a subset of genes and confirmed concordant results. Changes in transcript abundance biomarkers between sexes and seasons were evaluated to provide baseline data on transcript modulation for each species of interest.

Comparative Biochemistry and Physiology, Part D: G↗
USGS2025

Achieving interpretable machine learning by functional decomposition of black-box models into explainable predictor effects

Machine learning (ML) models are often based on complex black-box architectures that are difficult to interpret. This interpretability problem can hinder the use of ML in fields like medicine, ecology, and insurance, and has boosted research in interpretable machine learning (IML). Here, we propose a novel approach for the functional decomposition of black-box predictions, which is a core concept of IML. This approach replaces the prediction function with a surrogate model consisting of simpler subfunctions, providing insights into the direction and strength of the main feature contributions and their interactions. Our method is based on a concept termed “stacked orthogonality”, which ensures that the main effects capture as much functional behavior as possible. To compute the subfunctions, we combine neural additive modeling with an efficient post-hoc orthogonalization procedure. Our method yielded plausible results in an analysis of stream biological condition in the Chesapeake Bay watershed (United States).

Chesapeake Bay watershed↗
USGS2006

Sedimentation and Occurrence and Trends of Selected Chemical Constituents in Bottom Sediment, Empire Lake, Cherokee County, Kansas, 1905-2005

For about 100 years (1850-1950), the Tri-State Mining District in parts of southeast Kansas, southwest Missouri, and northeast Oklahoma was one of the primary sources of lead and zinc ore in the world. The mining activity in the Tri-State District has resulted in substantial historical and ongoing input of cadmium, lead, and zinc to the environment including Empire Lake in Cherokee County, southeast Kansas. The environmental contamination caused by the decades of mining activity resulted in southeast Cherokee County being listed on the U.S. Environmental Protection Agency's National Priority List as a superfund hazardous waste site in 1983. To provide some of the information needed to support efforts to restore the ecological health of Empire Lake, a 2-year study was begun by the U.S. Geological Survey in cooperation with the U.S. Fish and Wildlife Service and the Kansas Department of Health and Environment. A combination of sediment-thickness mapping and bottom-sediment coring was used to investigate sediment deposition and the occurrence of cadmium, lead, zinc, and other selected constituents in the bottom sediment of Empire Lake. The total estimated volume and mass of bottom sediment in Empire Lake were 44 million cubic feet and 2,400 million pounds, respectively. Most of the bottom sediment was located in the main body and the Shoal Creek arm of the reservoir. Minimal sedimentation was evident in the Spring River arm of the reservoir. The total mass of cadmium, lead, and zinc in the bottom sediment of Empire Lake was estimated to be 78,000 pounds, 650,000 pounds, and 12 million pounds, respectively. In the bottom sediment of Empire Lake, cadmium concentrations ranged from 7.3 to 76 mg/kg (milligrams per kilogram) with an overall median concentration of 29 mg/kg. Compared to an estimated background concentration of 0.4 mg/kg, the historical mining activity increased the median cadmium concentration by about 7,200 percent. Lead concentrations ranged from 100 to 950 mg/kg with an overall median concentration of 270 mg/kg. Compared to an estimated background concentration of 33 mg/kg, the median lead concentration was increased by about 720 percent as a result of mining activities. The range in zinc concentrations was 1,300 to 13,000 mg/kg with an overall median concentration of 4,900 mg/kg. Compared to an estimated background concentration of 92 mg/kg, the median zinc concentration was increased by about 5,200 percent. Within Empire Lake, the largest sediment concentrations of cadmium, lead, and zinc were measured in the main body of the reservoir. Within the Spring River arm of the reservoir, increased concentrations in the downstream direction likely were the result of tributary inflow from Short Creek, which drains an area that has been substantially affected by historical lead and zinc mining. Compared to nonenforceable sediment-quality guidelines, all Empire Lake sediment samples (representing 21 coring sites) had cadmium concentrations that exceeded the probable-effects guideline (4.98 mg/kg), which represents the concentration above which toxic biological effects usually or frequently occur. With one exception, cadmium concentrations exceeded the probable-effects guideline by about 180 to about 1,400 percent. With one exception, all sediment samples had lead concentrations that exceeded the probable-effects guideline (128 mg/kg) by about 10 to about 640 percent. All sediment samples had zinc concentrations that exceeded the probable-effects guideline (459 mg/kg) by about 180 to about 2,700 percent. Overall, cadmium, lead, and zinc concentrations in the bottom sediment of Empire Lake have decreased over time following the end of lead and zinc mining in the area. However, the concentrations in the most recently deposited bottom sediment (determined for 4 of 21 coring sites) still exceeded the probable-effects guideline by about 440 to 640 percent for cadmium, about 40 to 80 percent for lead, and about 580

Scientific Investigations Report↗
USGS2018

Assessing effects of nonnative crayfish on mosquito survival

Introductions of nonnative predators often reduce biodiversity and affect natural predator–prey relationships and may increase the abundance of potential disease vectors (e.g., mosquitoes) indirectly through competition or predation cascades. The Santa Monica Mountains (California, U.S.A.), situated in a global biodiversity hotspot, is an area of conservation concern due to climate change, urbanization, and the introduction of nonnative species. We examined the effect of nonnative crayfish (Procambarus clarkii) on an existing native predator, dragonfly nymphs (Aeshna sp.), and their mosquito larvae (Anopheles sp.) prey. We used laboratory experiments to compare the predation efficiency of both predators, separately and together, and field data on counts of dragonfly nymphs and mosquito larvae sampled from 13 local streams. We predicted a lower predation efficiency of crayfish compared with native dragonfly nymphs and a reduced predation efficiency of dragonfly nymphs in the presence of crayfish. Dragonfly nymphs were an order of magnitude more efficient predators than crayfish, and dragonfly nymph predation efficiency was reduced in the presence of crayfish. Field count data showed that populations of dragonfly nymphs and mosquito larvae were strongly correlated with crayfish presence in streams, such that sites with crayfish tended to have fewer dragonfly nymphs and more mosquito larvae. Under natural conditions, it is likely that crayfish reduce the abundance of dragonfly nymphs and their predation efficiency and thereby, directly and indirectly, lead to higher mosquito populations and a loss of ecosystem services related to disease vector control.

California↗
USGS2019

Plot Locator: An app for locating plots in the field

PREMISE: One of the challenges in field biology is locating previously sampled plots. The Plot Locator app was developed to assist field biologists with plot identification and location, with or without GPS or online connectivity. METHODS AND RESULTS: The Plot Locator Android app helps users locate field plots by creating a searchable database that stores study area information, such as site/plot names and numbers, distances from landmarks, optional cardinal directions and GPS coordinates, and field notes. A GPS assist and Google Maps can also be used with the app when connectivity is available. All study location data and field notes are stored in a downloadable CSV file on the user’s device. CONCLUSIONS: The Plot Locator app provides a comprehensive searchable database of study area information, plot location information, and location aids, which are easily accessed in the field.

Applications in Plant Science↗
USGS2000

Distribution and potential for adverse biological effects of inorganic elements and organic compounds in bottom sediment, lower Charles River, Massachusetts

Surficial-sediment samples and cores collected from the lower Charles River Basin are generally enriched in inorganic elements and organic compounds, including polychlorinated byphenyls, total organochlorine pesticides, and polyaromatic hydrocarbons. Median concentrations of selected inorganic elements and organic compounds measured in surficial-sediment samples collected from the lower Charles River ranged from 1. 3 to 3 5 times higher than median concentrations of these constituents measured in samples collected from urban rivers across the conterminous United States by the U.S. Geological Survey's National Water Quality Assessment Program (NAWQA). The distribution of the inorganic elements in surficial sediment throughout the basin appears to be controlled primarily by in-stream processes associated with sediment transport and the presence of an anoxic zone within a non-tidal salt wedge in the basin. In contrast, the distribution of organic compounds appears to reflect local point and non-point sources. Inorganic elements and organic compounds are present at sufficiently high concentrations at many surficial-sediment sampling sites to cause potentially severe biological effects to benthic organisms living in and on the bottom sediment. Ratios of acid volatile sulfide to simultaneously extracted metals, however, suggest that some inorganic elements would be toxic in fewer than 25 percent of the surficial-sediment samples. Many individual polyaromatic hydrocarbons, total petroleum hydrocarbons, and lead measured in cores exceeded exposure-based soil-concentration standards for direct contact and incident ingestion at areas where restoration of public wading and swimming beaches is being considered.

Massachusetts↗
USGS2021

Diel patterns of pheromone release by male sea lamprey

Costs to producing sexual signals can create selective pressures on males to invest signaling effort in particular contexts. When the benefits of signaling vary consistently across time, males can optimize signal investment to specific temporal contexts using biological rhythms. Sea lamprey, Petromyzon marinus , have a semelparous life history, are primarily nocturnal, and rely on pheromone communication for reproduction; however, whether male investment in pheromone transport and release matches increases in spawning activity remains unknown. By measuring (1) 3keto-petromyzonol sulfate (3kPZS, a main pheromone component) and its biosynthetic precursor PZS in holding water and tissue samples at six points over the course of 24 hours and (2) 3kPZS release over the course of several days, we demonstrate that 3kPZS release exhibits a consistent diel pattern across several days with elevated pheromone release just prior to sunset and at night. Trends in hepatic concentrations and circulatory transport of PZS and 3kPZS were relatively consistent with patterns of 3kPZS release and suggest the possibility of direct upregulation in pheromone transport and release rather than observed release patterns being solely a byproduct of increased behavioral activity. Our results suggest males evolved a signaling strategy that synchronizes elevated pheromone release with nocturnal increases in sea lamprey behavior. This may be imperative to ensure that male signaling effort is not wasted in a species having a single, reproductive event.

Integrative and Comparative Biology↗
USGS2019

Biological and mineralogical controls over cycling of low molecular weight organic compounds along a soil chronosequence

Low molecular weight organic compounds (LMWOC) represent a small but critical component of soil organic matter (SOM) for microbial growth and metabolism. The fate of these compounds is largely under microbial control, yet outside the cell, intrinsic soil properties can also significantly influence their turnover and retention. Using a chronosequence representing 1200 ka of pedogenic development, we compared physicochemical vs biological controls on the turnover and retention of fast-cycling carbon (C), e.g. glucose (GLU) and p-hydroxybenzoic acid (PHBA). Along the chronosequence, we observed mineralogical gradients whereby amorphous constituents were greatest in intermediate-aged sites, while older sites demonstrated soils with more ordered and less reactive mineralogy. Soil microbial community composition varied along the soil chronosequence and we observed reductions in total biomass and fungal biomass from younger to older sites, but this did not affect the turnover of LMWOC. Microbial utilization of LMWOC was substrate- and soil-dependent; amorphous Fe and Al oxides reduced the respiration of PHBA but respiration from glucose remained less affected. Variation in soil mineralogy did not significantly alter recovery of PHBA within microbial biomass or fungal vs. bacterial biomarkers, suggesting that reduced respiration of the phenolic resulted from direct mineral interaction with ionizable functional groups rather than changes to microbial allocation of PHBA. We conclude patterns of soil carbon storage observed across chronosequences are moderated by mineralogical effects on microbial access to LMWOC, independent of variation in microbial community composition. Keywords: 13C; Glucose; Microbial biomass C; Organo-mineral interactions; p-Hydroxybenzoic acid; Selective dissolution mineralogical analyses

Soil Biology and Biochemistry↗
USGS2008

Revisiting classic water erosion models in drylands: The strong impact of biological soil crusts

Soil erosion and subsequent degradation has been a contributor to societal collapse in the past and is one of the major expressions of desertification in arid regions. The revised universal soil loss equation (RUSLE) models soil lost to water erosion as a function of climate erosivity (the degree to which rainfall can result in erosion), topography, soil erodibility, and land use/management. The soil erodibility factor (K) is primarily based upon inherent soil properties (those which change slowly or not at all) such as soil texture and organic matter content, while the cover/management factor (C) is based on several parameters including biological soil crust (BSC) cover. We examined the effect of two more precise indicators of BSC development, chlorophyll a and exopolysaccharides (EPS), upon soil stability, which is closely inversely related to soil loss in an erosion event. To examine the relative influence of these elements of the C factor to the K factor, we conducted our investigation across eight strongly differing soils in the 0.8 million ha Grand Staircase-Escalante National Monument. We found that within every soil group, chlorophyll a was a moderate to excellent predictor of soil stability (R2 = 0.21-0.75), and consistently better than EPS. Using a simple structural equation model, we explained over half of the variance in soil stability and determined that the direct effect of chlorophyll a was 3?? more important than soil group in determining soil stability. Our results suggest that, holding the intensity of erosive forces constant, the acceleration or reduction of soil erosion in arid landscapes will primarily be an outcome of management practices. This is because the factor which is most influential to soil erosion, BSC development, is also among the most manageable, implying that water erosion in drylands has a solution. ?? 2008 Elsevier Ltd.

Soil Biology and Biochemistry↗
USGS2001

Conservation status and recovery strategies for endemic Hawaiian birds

Populations of endemic Hawaiian birds declined catastrophically following the colonization of the islands by Polynesians and later cultures. Extinction is still occurring, and recovery programs are urgently needed to prevent the disappearance of many other species. Programs to recover the endemic avifauna incorporate a variety of conceptual and practical approaches that are constrained by biological, financial, social, and legal factors. Avian recovery is difficult to implement in Hawai‘i because a variety of challenging biological factors limit bird populations. Hawaiian birds are threatened by alien predatory mammals, introduced mosquitoes that transmit diseases, alien invertebrate parasites and predators that reduce invertebrate food resources, and alien animals and plants that destroy and alter habitats. Life in the remote Hawaiian Archipelago has imposed other biological constraints to avian recovery, including limited geographical distributions and small population sizes. Recovery of the endemic avifauna is also challenging because resources are insufficient to mitigate the many complex, interacting factors that limit populations. Decisions must be made for allocating limited resources to species teetering on the brink of extinction and those in decline. If funds are spent primarily on saving the rarest species, more abundant species will decline and become more difficult to recover. However, critically rare species will disappear if efforts are directed mainly towards restoring species that are declining but not in immediate danger of becoming extinct. Determining priorities is difficult also because management is needed both to supplement bird populations and to restore habitats of many species. Rare species cannot respond quickly to management efforts intended only to improve habitat and reduce limiting factors. Recovery is slow, if it occurs at all, because years or decades are generally required for habitat rehabilitation and because small populations of birds initially increase slowly even when habitat conditions are favorable. Consequently, even as habitat conditions begin to improve, small populations may disappear unless they are supplemented directly. Hawaiian bird conservation is also affected by social and legal factors, including hunting alien game species, commercial land use practices, and lawsuits and policies concerning endangered species and critical habitat. Influenced by this mixture of conflicting and competing issues, Hawaiian bird recovery programs range from management of single species and some components of their habitats to limited forms of community or ecosystem management. Although the effectiveness of most programs is difficult to evaluate because of monitoring limitations, several programs exemplify species and community management. Programs primarily intended to recover single species include Hawaiian Goose or Nene ( Branta sandvicensis ), Hawaiian Crow or ‘Alala ( Corvus hawaiiensis ), and Palila ( Loxioides bailleui ). Programs attempting to manage entire communities of forest birds include Hakalau Forest National Wildlife Refuge and Hawai‘i Volcanoes National Park on Hawai‘i, and Waikamoi Preserve, Hanawi Natural Area Reserve, and Haleakala National Park on Maui.

Hawaii↗
USGS2005

Effects of coal-bed methane discharge waters on the vegetation and soil ecosystem in Powder River Basin, Wyoming

Coal-bed methane (CBM) co-produced discharge waters in the Powder River Basin of Wyoming, resulting from extraction of methane from coal seams, have become a priority for chemical, hydrological and biological research during the last few years. Soil and vegetation samples were taken from affected and reference sites (upland elevations and wetted gully) in Juniper Draw to investigate the effects of CBM discharge waters on soil physical and chemical properties and on native and introduced vegetation density and diversity. Results indicate an increase of salinity and sodicity within local soil ecosystems at sites directly exposed to CBM discharge waters. Elevated concentrations of sodium in the soil are correlated with consistent exposure to CBM waters. Clay-loam soils in the study area have a much larger specific surface area than the sandy soils and facilitate a greater sodium adsorption. However, there was no significant relation between increasing water sodium adsorption ratio (SAR) values and increasing sediment SAR values downstream; however, soils exposed to the CBM water ranged from the moderate to severe SAR hazard index. Native vegetation species density was highest at the reference (upland and gully) and CBM affected upland sites. The affected gully had the greatest percent composition of introduced vegetation species. Salt-tolerant species had the greatest richness at the affected gully, implying a potential threat of invasion and competition to established native vegetation. These findings suggest that CBM waters could affect agricultural production operations and long-term water quality.

Wyoming↗
USGS2009

Modeling co-occurrence of northern spotted and barred owls: accounting for detection probability differences

Barred owls (Strix varia) have recently expanded their range and now encompass the entire range of the northern spotted owl (Strix occidentalis caurina). This expansion has led to two important issues of concern for management of northern spotted owls: (1) possible competitive interactions between the two species that could contribute to population declines of northern spotted owls, and (2) possible changes in vocalization behavior and detection probabilities of northern spotted owls induced by presence of barred owls. We used a two-species occupancy model to investigate whether there was evidence of competitive exclusion between the two species at study locations in Oregon, USA. We simultaneously estimated detection probabilities for both species and determined if the presence of one species influenced the detection of the other species. Model selection results and associated parameter estimates provided no evidence that barred owls excluded spotted owls from territories. We found strong evidence that detection probabilities differed for the two species, with higher probabilities for northern spotted owls that are the object of current surveys. Non-detection of barred owls is very common in surveys for northern spotted owls, and detection of both owl species was negatively influenced by the presence of the congeneric species. Our results suggest that analyses directed at hypotheses of barred owl effects on demographic or occupancy vital rates of northern spotted owls need to deal adequately with imperfect and variable detection probabilities for both species.

Oregon↗
USGS2006

Emergence of ratio-dependent and predator-dependent functional responses for pollination mutualism and seed parasitism

Prey ( N ) dependence [ g ( N )], predator ( P ) dependence [ g ( P ) or g ( N , P )], and ratio dependence [ f ( P / N )] are often seen as contrasting forms of the predator's functional response describing predator consumption rates on prey resources in predator–prey and parasitoid–host interactions. Analogously, prey-, predator-, and ratio-dependent functional responses are apparently alternative functional responses for other types of consumer–resource interactions. These include, for example, the fraction of flowers pollinated or seeds parasitized in pollination (pre-dispersal) seed-parasitism mutualisms, such as those between fig wasps and fig trees or yucca moths and yucca plants. Here we examine the appropriate functional responses for how the fraction of flowers pollinated and seeds parasitized vary with the density of pollinators (predator dependence) or the ratio of pollinator and flower densities (ratio dependence). We show that both types of functional responses can emerge from minor, but biologically important variations on a single model. An individual-based model was first used to describe plant–pollinator interactions. Conditional upon on whether the number of flowers visited by the pollinator was limited by factors other than search time (e.g., by the number of eggs it had to lay, if it was also a seed parasite), and on whether the pollinator could directly find flowers on a plant, or had to search, the simulation results lead to either a predator-dependent or a ratio-dependent functional response. An analytic model was then used to show mathematically how these two cases can arise.

Ecological Modelling↗
USGS2013

Extreme CO 2 disturbance and the resilience of soil microbial communities

Carbon capture and storage (CSS) technology has the potential to inadvertently release large quantities of CO 2 through geologic substrates and into surrounding soils and ecosystems. Such a disturbance has the potential to not only alter the structure and function of plant and animal communities, but also soils, soil microbial communities, and the biogeochemical processes they mediate. At Mammoth Mountain, we assessed the soil microbial community response to CO 2 disturbance (derived from volcanic ‘cold’ CO 2 ) that resulted in localized tree kill; soil CO 2 concentrations in our study area ranged from 0.6% to 60%. Our objectives were to examine how microbial communities and their activities are restructured by extreme CO 2 disturbance, and assess the response of major microbial taxa to the reintroduction of limited plant communities following an extensive period (15–20 years) with no plants. We found that CO 2 -induced tree kill reduced soil carbon (C) availability along our sampling transect. In response, soil microbial biomass decreased by an order of magnitude from healthy forest to impacted areas. Soil microorganisms were most sensitive to changes in soil organic C, which explained almost 60% of the variation for microbial biomass C (MBC) along the CO 2 gradient. We employed phospholipid fatty acid analysis and quantitative PCR (qPCR) to determine compositional changes among microbial communities in affected areas and found substantial reductions in microbial biomass linked to the loss of soil fungi. In contrast, archaeal populations responded positively to the CO 2 disturbance, presumably due to reduced competition of bacteria and fungi, and perhaps unique adaptations to energy stress. Enzyme activities important in the cycling of soil C, nitrogen (N), and phosphorus (P) declined with increasing CO 2 , though specific activities (per unit MBC) remained stable or increased suggesting functional redundancy among restructured communities. We conclude that both the direct (microaerobiosis) and indirect (loss of plant C inputs) effects of elevated soil CO 2 flux have significant impacts on the composition and overall structural trajectory of soil microbial populations within disturbed areas.

California↗