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At least 685 records · Page 38Linked to original sources

USGS1988

A field test for differences in condition among trapped and shot mallards

We tested predictions from the condition bias hypothesis (Weatherland and Greenwood 1981) regarding the effects of sampling methods of body weights of mallards ( Anas platyrhynchos ) at White River National Wildlife Refuge (WRNWR), Arkansas, during 24 November-8 December 1985. Body weights of 84 mallards caught with unbaited rocket nets in a natural wetland were used as experimental controls and compared to the body weights of 70 mallards captured with baited rocket nets, 86 mallards captured with baited swim-in traps, and 130 mallards killed by hunters. We found no differences (P > 0.27) in body weight among sampling methods, but body condition (wt/wing length) of the birds killed by hunters was less (P < 0.02) than that of the controls. Power of the test statistics to reject the null hypothesis of equal body weights among sampling methods was > 0.75 for differences > 50 g. The condition bias hypothesis probably applies to ducks killed by hunters but not to trapping operations when substantial (> 20 at 1 time) numbers of birds are captured.

Arkansas↗

USGS2023

Comprehensive water-quality trend analysis for selected sites and constituents in the International Souris River Basin, Saskatchewan and Manitoba, Canada, and North Dakota, United States, 1970–2020

The Souris River Basin is an international basin in southeast Saskatchewan, north-central North Dakota, and southwest Manitoba. Sustained exceedances of water-quality objectives for total phosphorus, sodium, sulfate, total dissolved solids, and total iron have been reported since the late 1990s at the two binational sites on the Souris River (Souris River near Sherwood, North Dakota [U.S. Geological Survey station 05114000] and Souris River near Westhope, N. Dak. [U.S. Geological Survey station 05124000]). To understand conditions at the binational sites, it is important to understand water-quality changes on a basin-wide scale. Because streamflow is highly variable in the basin and changes in streamflow affect water-quality conditions, it is particularly important to use a trend-analysis method that accounts for changes in streamflow. Trends in water-quality concentrations can be affected by human-induced changes on the landscape or natural changes in land-runoff interactions that are driven by climate patterns and reflected by changes in streamflow (commonly referred to as “hydroclimatic variability”). In the primarily agricultural Souris River Basin, human-induced changes that are likely to affect trends are widespread changes in agricultural management such as fertilizer application, tilling practices, and crop types, as well as dam emplacement and artificial drainage. Around 1970, there was a long-term natural (hydroclimatic) change in the basin in which a significant transition from a dry climate state to a wet climate state resulted in higher streamflow in the basin. To assist the International Souris River Board in assessing current water-quality conditions in the Souris River Basin and exceedances of water-quality objectives at the binational sites, the U.S. Geological Survey, in cooperation with the International Joint Commission, completed a comprehensive analysis for selected ions, nutrients, and trace metals for many sites in the basin that included descriptive water-quality statistics, trend analysis using a trend method that considers interannual hydroclimatic variability, and an assessment of exceedances of the water-quality objectives for the binational sites. Water-quality and streamflow or reservoir inflow or outflow data were compiled for 34 sites (30 stream sites and four reservoir sites) and 23 constituents with established water-quality objectives from 1970 to 2020 in the Souris River Basin and were used for descriptive statistics and water-quality trend analysis. Median total dissolved solids, sulfate, and sodium concentrations were low in the headwaters of the Souris River and some of the highest median concentrations were measured in the upper basin. At main-stem Souris River sites, all median sodium concentrations were greater than the binational water-quality objective. Median total phosphorus concentrations in the Souris River Basin were highest in the headwaters of the Souris River and all sites had median concentrations greater than the water-quality objective. Median total iron concentrations were highly variable across the basin, and for most main-stem sites, median concentrations were greater than or equal to the water-quality objective. During the recent period (2009–19), the annual flow-averaged concentrations of total dissolved solids and sulfate increased for nearly all stream sites with most sites having mildly significant or significant increases. One-half of the sites had an annual flow-averaged geometric mean concentration greater than the total dissolved solids water-quality objective, and four sites had sulfate increases greater than 100 milligrams per liter. Trends in annual flow-averaged concentrations of sodium and chloride generally were small and nonsignificant. Most sites had concentrations greater than the sodium water-quality objective, whereas all sites had concentrations much less than the chloride water-quality objective. Annual flow-averaged geometric mean concentration of total phosphorus decreased for nearly all sites across the Souris River Basin, but all sites had concentrations greater than the total phosphorus water-quality objective for the entire period. Small and nonsignificant changes in annual flow-averaged geometric mean concentration of total iron were detected at all sites but the binational site at Sherwood, N. Dak., and by 2019 all sites had concentrations greater than the total iron water-quality objective. For the reservoir sites, during 2000–15, mostly significant increases for total dissolved solids, sulfate, and sodium were detected, whereas changes in total phosphorus and total iron were mixed. During the historical period (1976–2019), large and consistent increases in total dissolved solids and sulfate have occurred since the late 1980s, with the largest increases and the most sites with mildly significant or significant increases generally occurring during the middle period (1988–2005). Large and significant or mildly significant increases in sodium concentrations occurred at eight of 10 sites in the middle period (1988–2005), and by the late period (2005–19) changes were small and nonsignificant. Similar to other basins in the region, such as the Red River of the North and Heart River, large and overall consistent increases since the late 1980s in total dissolved solids and sulfate in the Souris River Basin suggest that long-term natural (hydroclimatic) processes are large contributors to increases in the concentration of salts in streams and reservoirs associated with the onset of wetter conditions. The concurrent increases in sulfate and sodium concentrations at all sites during the middle period (1988–2005) suggest that sodium-sulfate evaporite dissolution may be a factor contributing to increases. Total phosphorus concentrations oscillated between increasing and decreasing during the historical period, with concentrations increasing during the first trend period (1976–88) and decreasing in the fourth trend period (2009–19) to the lowest flow-averaged geometric mean concentration by 2019 for most sites. During the historical period, changes in total iron concentrations were mostly nonsignificant and generally small, and variability in total iron concentrations likely affected the ability to detect statistically significant changes in concentration. The probability of exceeding the water-quality objective for total dissolved solids, sulfate, and sodium increased between 1976 and 2019 for the binational sites, especially for sulfate, which more than doubled for Souris River near Sherwood, N. Dak. and increased more than seven times for Souris River near Westhope, N. Dak. Total phosphorus and total iron concentrations for the binational sites were likely to exceed the water-quality objective for most of the year, but seasonal patterns of total phosphorus and total iron concentrations were different between the sites, suggesting that different factors may affect concentrations at different times of the year. For sodium, total phosphorus, and total iron, exceedance of the water-quality objective most of the time is not unexpected given that the flow-averaged geometric mean concentration for these three constituents for most sites across the basin are greater than the water-quality objective for most of the period. If natural processes are affecting total dissolved solids and sulfate concentrations, concentrations would be expected to vary with time, and as a result, extended periods of concentrations greater or less than the water-quality objective are likely to occur depending upon climatic conditions. A better understanding of the state of water quality across the Souris River Basin is beneficial to understanding and interpreting water-quality conditions at the two Souris River binational sites. The most consistent spatial and temporal change observed for this study was large and consistent increases in sulfate and total dissolved solids among tributary and main-stem sites since the late 1980s. For sulfate and total dissolved solids, wetter climatic conditions combined with naturally occurring and abundant sources of sulfate likely contributed to sustained exceedances of water-quality objectives in recent decades, and extended periods of concentrations greater than or less than the water-quality objective are likely to occur depending on climatic conditions. For sodium, total iron, and total phosphorus, sustained exceedances of the current water-quality objective likely will continue because most sites across the basin had flow-averaged geometric mean concentrations greater than the water-quality objective; and during the 43-year period of analysis, regardless of climatic conditions, exceedances were consistently greater than the water-quality objective. Further investigation into the factors causing increasing sulfate concentrations and a better understanding of reservoir dynamics would enhance the understanding of changes in water-quality conditions in the Souris River Basin. The basin-wide approach of this report provided an improved understanding of water-quality conditions in the Souris River Basin, and results can be used to inform the current water-quality objectives, inform potential changes to water management in the basin, and serve as a starting point for tracking future progress. Gaps in understanding of water-quality conditions can be closed through continued monitoring and further investigation into causes behind changes in water-quality conditions identified in this report.

Manitoba, North Dakota, Saskatchewan↗

USGS2018

A method to quantify and value floodplain sediment and nutrient retention ecosystem services

Floodplains provide critical ecosystem services to local and downstream communities by retaining floodwaters, sediments, and nutrients. The dynamic nature of floodplains is such that these areas can both accumulate sediment and nutrients through deposition, and export material downstream through erosion. Therefore, estimating floodplain sediment and nutrient retention should consider the net flux of both depositional and erosive processes. An ecosystem services framework was used to quantify and value the sediment and nutrient ecosystem service provided by floodplains in the Difficult Run watershed, a small (151 km 2 ) suburban watershed located in the Piedmont of Virginia (USA). A sediment balance was developed for Difficult Run and two nested watersheds. The balance included upland sediment delivery to streams, stream bank flux, floodplain flux, and stream load. Upland sediment delivery was estimated using geospatial datasets and a modified Revised Universal Soil Loss Equation. Predictive models were developed to extrapolate field measurements of the flux of sediment, sediment-bound nitrogen (N), and sediment-bound phosphorus (P) from stream banks and floodplains to 3232 delineated stream segments in the study area. A replacement cost approach was used to estimate the economic value of the sediment and nutrient retention ecosystem service based on estimated net stream bank and floodplain flux of sediment-bound N for all streams in the study area. Results indicated the net fluvial fluxes of sediment, sediment-bound N, and sediment-bound P were −10,439 Mg yr −1 (net export), 57,300 kg-N yr −1 (net trapping), and 98 kg-P yr −1 (net trapping), respectively. For sediment, floodplain retention was offset by substantial losses from stream bank erosion, particularly in headwater catchments, resulting in a net export of sediment. Nutrient retention in the floodplain exceeded that lost through stream bank erosion resulting in net retention of nutrients (TN and TP). Using a conservative cost estimate of \$12.69 (USD) per kilogram of nitrogen, derived from wastewater treatment costs, the estimated annual value for sediment and nutrient retention on Difficult Run floodplains was \$727,226 ± 194,220 USD/yr. Values and differences in floodplain nitrogen retention among stream reaches can be used to target areas for floodplain conservation and stream restoration. The methods presented are scalable and transferable to other areas if appropriate datasets are available for validation.

Virginia↗

USGS2019

Age and growth of stocked juvenile Shoal Bass in a tailwater: Environmental variation and accuracy of daily age estimates

Otolith microanalysis is often used to assess population age structure and growth of fishes during their early stages. Shoal Bass Micropterus cataractae is a recently described species of conservation concern and little is known regarding factors affecting their recruitment. In 2004, Georgia Department of Natural Resources (GADNR) and the US National Park Service (NPS) stocked Shoal Bass marked with oxytetracycline (OTC) in the Chattahoochee River near Atlanta, Georgia in an effort to restore this population, creating known-age fish to examine the effect of environment on daily age accuracy. We obtained samples of stocked juvenile (<150 mm) Shoal Bass from standard monitoring that occurred approximately 30–60 days after stocking in the Chattahoochee River to 1) validate daily rings for estimating age, hatch dates, and growth rates for stocked age-0 Shoal Bass, and 2) evaluate the effect of habitat (location) on age bias. Shoal Bass otoliths were examined for OTC marks and daily rings were counted in reference to OTC marks to assess age estimation accuracy. Age estimation accuracy ranged from -2 to -25 days and was influenced by the environment where Shoal Bass were captured, with greater inaccuracy in colder water temperatures. Fish collected from locations with colder temperatures displayed closer spacing of daily rings, potentially leading to greater underestimation of age. Growth rates of stocked Shoal Bass, corrected for age estimation error, ranged from 0.5 mm/day to 0.8 mm/day. This study demonstrates the effect of environmental variability on age inaccuracy and subsequent interpretation of results. Incorporating methods to assess age estimation accuracy is needed to understand interspecific differences in recruitment among black bass species in the variety of natural and human-modified environments they inhabit.

Georgia↗

USGS2023

Forecasting natural regeneration of sagebrush after wildfires using population models and spatial matching

Context Addressing ecosystem degradation in the Anthropocene will require ecological restoration across large spatial extents. Identifying areas where natural regeneration will occur without direct resource investment will improve scalability of restoration actions. Objectives An ecoregion in need of large scale restoration is the Great Basin of the Western US, where increasingly large and frequent wildfires threaten ecosystem integrity and its foundational shrub species. We develop a framework to forecast where post-wildfire regeneration of sagebrush cover ( Artemisia spp.) is likely to occur within the burnt areas across the region (> 900,000 km 2 ). Methods First, we parameterized population models using Landsat satellite-derived time series of sagebrush cover. Second, we evaluated the out-of-sample performance by predicting natural regeneration in wildfires not used for model training. This model assessment reproduces a management-oriented scenario: making restoration decisions shortly after wildfires with minimal local information. Third, we asked how accounting for increasingly fine-scale spatial heterogeneity could improve model forecasting accuracy. Results Regional-level models revealed that sagebrush post-fire recovery is slow, estimating > 80-year time horizon to reach an average cover at equilibrium of 16.6% (CI95% 9–25). Accounting for wildfire and within-wildfire spatial heterogeneity improved out-of-sample forecasts, resulting in a mean absolute error of 3.5 ± 4.3% cover, compared to the regional model with an error of 7.2 ± 5.1% cover. Conclusions We demonstrate that combining population models and non-parametric spatial matching provides a flexible framework for forecasting plant population recovery. Models for population recovery applied to Landsat-derived time series will assist restoration decision-making, including identifying priority targets for restoration.

Great Basin↗

USGS2002

Lyme disease and conservation

Lyme disease is a tick-borne illness that is widespread in North America, especially in the northeastern and northcentral United States. This disease could negatively influence efforts to conserve natural populations in two ways: (1) the disease could directly affect wild animal health; and (2) tick control efforts could adversely affect natural populations and communities. Lyme disease affects several domestic animals, but symptoms have been reported in only a few wild species. Direct effects of Lyme disease on wild animal populations have not been reported, but the disease should be considered as a possible cause in cases of unexplained population declines in endemic areas. Methods available to manage ticks and Lyme disease include human self-protection techniques, manipulation of habitats and host species populations, biological control, and pesticide applications. The diversity of available techniques allows selection of approaches to minimize environmental effects by (1) emphasizing personal protection techniques, (2) carefully targeting management efforts to maximize efficiency, and (3) integrating environmentally benign techniques to improve management while avoiding broad-scale environmentally destructive approaches. The environmental effects of Lyme disease depend, to a large extent, on the methods chosen to minimize human exposure to infected ticks. Conservation biologists can help design tick management programs that effectively lower the incidence of human Lyme disease while simultaneously minimizing negative effects on natural populations.

Conservation Biology↗

USGS1983

Human interactions with ground-water

Ground-Water could be considered as an immense reservoir, from which only a certain amount of water can be withdrawn without affecting the quantity and quality of water. This amount is determined by the characteristics of the environment in which ground-water occurs and by the interactions of ground-water with precipitation, surface water, and people. It should be recognized that quantity and quality of ground-water are intimately related and should be considered accordingly. Quantity refers to usable water and water is usable for any specific purpose only so long as its quality has not deteriorated beyond acceptable limits. Thus an overall quantitative and qualitative management of ground water is inevitable, and its should also involve the uses of ground-water reservoirs for purposes other than water supply. The main objective of ground-water management is to ensure that ground-water resources will be available in appropriate time and in appropriate quantity and quality to meet the most important demands of our society. Traditional, and obvious uses of ground-water are the extraction of water for water supplies (domestic, municipal, agricultural, and industrial) and the natural discharge feeding lakes and maintaining base flow of streams. Not so obvious are the uses of ground-water reservoirs, the very framework within which ground-water occurs and moves, and in which other fluids or materials can be stored. In the last two decades, ground-water reservoirs have been intensively considered for many other purposes than water supplies. Diversified and very often conflicting uses need to be evaluated and dealt with in the most efficient way in order to determine the importance of each possible use, and to assign priorities of these uses. With rising competition for the use of ground-water reservoirs, we will also need to increase the potential for effective planning of ground-water development and protection. Man's development and use of ground-water necessarily modifies the natural conditions and the total natural system must be successfully blended with the unnatural stresses placed upon it. This can be accomplished by introducing new methods (such as ground-water zoning) in and by developing alternative strategies for ground-water management and protection. ?? 1983 D. Reidel Publishing Company.

GeoJournal↗

USGS2005

Topographic, bioclimatic, and vegetation characteristics of three ecoregion classification systems in North America: Comparisons along continent-wide transects

Ecoregion classification systems are increasingly used for policy and management decisions, particularly among conservation and natural resource managers. A number of ecoregion classification systems are currently available, with each system defining ecoregions using different classification methods and different types of data. As a result, each classification system describes a unique set of ecoregions. To help potential users choose the most appropriate ecoregion system for their particular application, we used three latitudinal transects across North America to compare the boundaries and environmental characteristics of three ecoregion classification systems [Ku??chler, World Wildlife Fund (WWF), and Bailey]. A variety of variables were used to evaluate the three systems, including woody plant species richness, normalized difference in vegetation index (NDVI), and bioclimatic variables (e.g., mean temperature of the coldest month) along each transect. Our results are dominated by geographic patterns in temperature, which are generally aligned north-south, and in moisture, which are generally aligned east-west. In the west, the dramatic changes in physiography, climate, and vegetation impose stronger controls on ecoregion boundaries than in the east. The Ku??chler system has the greatest number of ecoregions on all three transects, but does not necessarily have the highest degree of internal consistency within its ecoregions with regard to the bioclimatic and species richness data. In general, the WWF system appears to track climatic and floristic variables the best of the three systems, but not in all regions on all transects. ?? 2005 Springer Science+Business Media, Inc.

Environmental Management↗

USGS2012

Deterministic estimation of hydrological thresholds for shallow landslide initiation and slope stability models: case study from the Somma-Vesuvius area of southern Italy

Rainfall-induced debris flows involving ash-fall pyroclastic deposits that cover steep mountain slopes surrounding the Somma-Vesuvius volcano are natural events and a source of risk for urban settlements located at footslopes in the area. This paper describes experimental methods and modelling results of shallow landslides that occurred on 5–6 May 1998 in selected areas of the Sarno Mountain Range. Stratigraphical surveys carried out in initiation areas show that ash-fall pyroclastic deposits are discontinuously distributed along slopes, with total thicknesses that vary from a maximum value on slopes inclined less than 30° to near zero thickness on slopes inclined greater than 50°. This distribution of cover thickness influences the stratigraphical setting and leads to downward thinning and the pinching out of pyroclastic horizons. Three engineering geological settings were identified, in which most of the initial landslides that triggered debris flows occurred in May 1998 can be classified as (1) knickpoints, characterised by a downward progressive thinning of the pyroclastic mantle; (2) rocky scarps that abruptly interrupt the pyroclastic mantle; and (3) road cuts in the pyroclastic mantle that occur in a critical range of slope angle. Detailed topographic and stratigraphical surveys coupled with field and laboratory tests were conducted to define geometric, hydraulic and mechanical features of pyroclastic soil horizons in the source areas and to carry out hydrological numerical modelling of hillslopes under different rainfall conditions. The slope stability for three representative cases was calculated considering the real sliding surface of the initial landslides and the pore pressures during the infiltration process. The hydrological modelling of hillslopes demonstrated localised increase of pore pressure, up to saturation, where pyroclastic horizons with higher hydraulic conductivity pinch out and the thickness of pyroclastic mantle reduces or is interrupted. These results lead to the identification of a comprehensive hydrogeomorphological model of susceptibility to initial landslides that links morphological, stratigraphical and hydrological conditions. The calculation of intensities and durations of rainfall necessary for slope instability allowed the identification of deterministic hydrological thresholds that account for uncertainty in properties and observed rainfall intensities.

Landslides↗

USGS2012

Maximizing the utility of monitoring to the adaptive management of natural resources

Data collection is an important step in any investigation about the structure or processes related to a natural system. In a purely scientific investigation (experiments, quasi-experiments, observational studies), data collection is part of the scientific method, preceded by the identification of hypotheses and the design of any manipulations of the system to test those hypotheses. Data collection and the manipulations that precede it are ideally designed to maximize the information that is derived from the study. That is, such investigations should be designed for maximum power to evaluate the relative validity of the hypotheses posed. When data collection is intended to inform the management of ecological systems, we call it monitoring. Note that our definition of monitoring encompasses a broader range of data-collection efforts than some alternative definitions – e.g. Chapter 3. The purpose of monitoring as we use the term can vary, from surveillance or “thumb on the pulse” monitoring (see Nichols and Williams 2006), intended to detect changes in a system due to any non-specified source (e.g. the North American Breeding Bird Survey), to very specific and targeted monitoring of the results of specific management actions (e.g. banding and aerial survey efforts related to North American waterfowl harvest management). Although a role of surveillance monitoring is to detect unanticipated changes in a system, the same result is possible from a collection of targeted monitoring programs distributed across the same spatial range (Box 4.1). In the face of limited budgets and many specific management questions, tying monitoring as closely as possible to management needs is warranted (Nichols and Williams 2006). Adaptive resource management (ARM; Walters 1986, Williams 1997, Kendall 2001, Moore and Conroy 2006, McCarthy and Possingham 2007, Conroy et al. 2008a) provides a context and specific purpose for monitoring: to evaluate decisions with respect to achievement of specific management objectives; and to evaluate the relative validity of predictive system models. This latter purpose is analogous to the role of data collection within the scientific method, in a research context.

Book chapter↗

USGS2012

Use of a seismic air gun to reduce survival of nonnative lake trout embryos: A tool for conservation?

The detrimental impacts of nonnative lake trout Salvelinus namaycush in the western USA have prompted natural resource management agencies in several states to implement lake trout suppression programs. Currently, these programs rely on mechanical removal methods (i.e., gill nets, trap nets, and angling) to capture subadult and adult lake trout. We conducted a study to explore the potential for using high-intensity sound from a relatively small (655.5 cm 3 [40 in 3 ]) seismic air gun to reduce survival of lake trout embryos. Lake trout embryos at multiple stages of development were exposed to a single discharge of the seismic air gun at two depths (5 and 15 m) and at two distances from the air gun (0.1 and 2.7 m). Control groups for each developmental stage, distance, and depth were treated identically except that the air gun was not discharged. Mortality in lake trout embryos treated at 0.1 m from the air gun was 100% at 74 daily temperature units in degrees Celsius (TU°C) at both depths. Median mortality in lake trout embryos treated at 0.1 m from the air gun at 207 TU°C (93%) and 267 °C (78%) appeared to be higher than that of controls (49% and 48%, respectively) at 15-m depth. Among the four lake trout developmental stages, exposure to the air gun at 0.1 m resulted in acute mortality up to 60% greater than that of controls. Mortality at a distance of 2.7 m did not appear to differ from that of controls at any developmental stage or at either depth. Our results indicate that seismic air guns have potential as an alternative tool for controlling nonnative lake trout, but further investigation is warranted.

North American Journal of Fisheries Management↗

USGS1999

Preliminary survey for entomopathogenic fungi associated with Ixodes scapularis (Acari: Ixodidae) in southern New York and New England, USA

Free-living larval, nymphal, and adult Ixodes scapularis Say were collected from scattered locales in southern New England and New York to determine infection rates with entomopathogenic fungi. Infection rates of larvae, nymphs, males, and females were 0% (571), 0% (272), 0% (57), and 4.3% (47), respectively. Two entomopathogenic fungi were isolated from field-collected I. scapularis females from Fire Island, NY. Isolates were identified as Verticillium lecanii (Zimmermann) Viegas and Verticillium sp. (a member of the Verticillium lecanii species complex). Ixodes scapularis Say is the principal vector of Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner ( Burgdorfer et al. 1982 , Johnson et al. 1984 ), the etiologic agent of Lyme disease in the northeastern and upper-midwestern United States. Control of I. scapularis is based on chemical treatment ( Mather et al. 1987b ; Schulze et al. 1987 , 1991 ), environmental management ( Wilson et al. 1988 , Schulze et al. 1995 ), and habitat modification ( Wilson 1986 ). These methods have shown variable success, and some potentially have negative environmental effects ( Wilson and Deblinger 1993 , Ginsberg 1994 ). Studies concerning natural predators, parasitoids, and pathogens of I. scapularis are rare. The use of ground-dwelling birds as tick predators has had only limited success ( Duffy et al. 1992 ). Nymphal I. scapularis are often infected with the parasitic wasp Ixodiphagus hookeri (Howard) ( Mather et al. 1987a , Hu et al. 1993 , Stafford et al. 1996 , Hu and Hyland 1997 ), but this wasp does not effectively control I. scapularis populations ( Stafford et al. 1996 ). The entomopathogenic nematodes Steinernema carpocapsae (Weiser) and S. glaseri (Steiner) are pathogenic only to engorged female I. scapularis, and thus have limited applicability ( Zhioua et al. 1995 ). In contrast, the entomogenous fungus Metarhizium anisopliae (Metschnikoff) Sorokin is highly pathogenic to all stages of I. scapularis, unfed as well as engorged, and thus has considerable potential as a microbial control agent ( Zhioua et al. 1997 ). European studies have suggested that entomopathogenic fungi might serve as natural controls of of Ixodes ricinus L. populations ( Samsinakova et al. 1974 , Eilenberg et al. 1991 , Kalsbeek et al. 1995 ). In the current study, we describe the isolation of entomopathogenic fungi from field-collected I. scapularis.

Journal of Medical Entomology↗

USGS2021

A chemical and bio‐herbicide mixture increased exotic invaders, both targeted and non‐targeted, across a diversely invaded landscape after fire

Questions Invasive‐plant treatments often target a single or few species, but many landscapes are diversely invaded. Exotic annual grasses (EAGs) increase wildfires and degrade native perennial plant communities in cold‐desert rangelands, and herbicides are thus sprayed to inhibit EAG germination and establishment. We asked how EAG target and non‐target species responded to an herbicide mixture sprayed over a large, topographically diverse landscape after wildfire. We focused on how whole‐community and natural EAG‐pathogen treatment responses varied over years and physical properties of sites. Location Sagebrush steppe of southwest Idaho, USA. Methods We monitored plant cover and diversity in 41 pairs of plots located inside or outside areas (486 ha total) treated with a combined aerial broadcast spray of pre‐emergent herbicide (imazapic) and weed‐suppressive bacteria ( Pseudomonas fluorescens , “MB906”) to target EAGs after wildfires. Results EAG cover and exotic species richness were initially less in treated plots but increased to levels similar to or greater than those of untreated plots by the third post‐treatment year. The EAG pathogen Ustilago bullata was not directly affected by the treatment. The treatment increased exotic perennial forb cover in all plots and exotic annual forb cover in cooler/wetter plots but reduced exotic annual forb cover in warmer/drier plots. Cover of the invasive biennial grass Poa bulbosa decreased more across study years in untreated than treated plots. Among natives, the treatment reduced perennial grass cover and annual forb presence but led to marginal increases in perennial forb cover and, on soils with less gravel, increased shrub presence. Conclusions A treatment targeting a single plant functional group did not achieve lasting success in these diversely invaded communities. Spraying alone did not release native perennials sufficiently to counteract the simultaneous release of secondary invaders and the return of target invaders. Planting or seeding may also be needed to achieve management goals.

Idaho↗

USGS2006

Monitoring of changes in quality of ground water

Ground water of acceptable quality is commonly interspersed with water of inferior quality. Water of inferior quality may be naturally occurring salty water commonly underlying fresh water, or it may be enclaves of contaminated water from wastes that lie in the fresh-water bodies. Disposal of wastes on and in the ground and pumping of water from wells cause a dispersion of contaminated water; migration of contaminated water toward wells may be spontaneously induced by the natural hydraulic gradient, or it may be induced artificially by the cone of depression about one or more wells. Economic methods of determining precisely the boundary zones between contaminated and uncontaminated water are not available. Much reliance is placed on monitoring wells. A prerequisite to monitoring is a synthetic hydrogeologic framework or model in which the behavior of the contaminated water is conceived. Such a conceptual model, using pertinent data that are available, helps to assess the need for monitoring and to guide a monitoring program for optimum results. Unplanned, indiscriminate monitoring of water from wells is expensive, inefficient, and fallible. The need for monitoring will increase in the future; yet, the proper objective is to improve the technology of determining the distribution of contaminated water so that monitoring can be minimized and conducted with optimum results.

Groundwater↗

USGS2019

Determining Moho depth beneath sedimentary basins using regional Pn multiples

The study of the Moho beneath thick sedimentary basins involving natural earthquakes is challenging, as low‐velocity materials often cause strong reverberations that mask Moho signals. Here, we develop a method to determine the depth of the Moho by taking advantage of the presence of the sediments. The method utilizes the first Pn crustal multiple from regional earthquakes PnPn and its differential travel time with respect to Pn. PnPn is usually weak in amplitude; thus, it is difficult to identify in regions without a sedimentary cover. However, PnPn is significantly amplified in the presence of low‐velocity sediments because of an increase in the near‐surface P‐to‐P reflection coefficient. The arrival time, amplitude, and wave shape of PnPn, if normalized by the reference Pn, are insensitive to earthquake source parameters, such as focal mechanism and focal depth. We demonstrate the potential of this method using both 1D and 2D waveform simulations. Synthetic waveforms suggest that PmpPn and PnPmp (one Pn leg merges to PmP near the source or the receiver) largely contribute to the PnPn amplitudes, which depend on the near‐surface structure at their free‐surface P‐to‐P reflection points. We further validate the method with two field examples in the Imperial Valley; one is near the United States–Mexico border, and the other is in Oklahoma in the central United States. Both examples suggest that the method can be used to study the Moho either near the source or the receiver.

Bulletin of the Seismological Society of America↗

USGS2025

U.S. Geological Survey Pollinator Science Strategy, 2025–35—A Review and Look Forward

This “U.S. Geological Survey Pollinator Science Strategy, 2025–35—A Review and Look Forward” (“Pollinator Science Strategy”) describes the science vision of the U.S. Geological Survey (USGS) to support management, conservation, and policy decisions on animal pollinators and their habitats. As the science arm of the Department of the Interior, the USGS has a primary role in providing scientific information to natural resource managers and policymakers across the United States. This “Pollinator Science Strategy” was drafted by a team of USGS pollinator researchers and was further developed through feedback from Federal, State, Tribal, nongovernmental organizations, and industry partners. This “Pollinator Science Strategy” highlights the USGS’s role in the research to promote healthy pollinator populations and address partner information gaps so they can make more informed management decisions. By outlining the importance of USGS science in addressing the information needs of other agencies, organizations, and the public, the “Pollinator Science Strategy” reaffirms the USGS’s commitment to pollinator research and showcases our research priorities for 2025–35. With more than 300 research centers nationally, the USGS is equipped to address pollinator science across scales of complexity and geographic range. USGS pollinator science is organized according to the following five thematic areas: Assessing species ecology, distributions, and natural history requirements. Tracking species status and trends. Understanding species threats and stressors. Informing restoration and management actions. Developing novel methods for improving pollinator research, monitoring, and population outcomes that can benefit our Nation. Our pollinator information products and associated data are made widely available to the public to ensure scientific transparency and accessibility. This “Pollinator Science Strategy” concludes with several research goals that the USGS will work towards from 2025 to 2035, representing our vision for USGS science. These research goals include synthesizing and modernizing the latest information on pollinator threats, developing research that assists managers with habitat design and restoration, providing training to partners on native bee identification and monitoring design, and developing new technologies for assessing the status and trends of our nation’s pollinators.

Circular↗

USGS2005

Southern California — Wildfires and debris flows

Wildland fires are inevitable in the western United States. Expansion of man-made developments into fire-prone wildlands has created situations where wildfires can destroy lives and property, as can the flooding and debris flows that are common in the aftermath of the fires. Fast-moving, highly destructive debris flows triggered by intense rainfall are one of the most dangerous post-fire hazards. Such debris flows are particularly dangerous because they tend to occur with little warning. Their mass and speed make them particularly destructive: debris flows can strip vegetation, block drainages, damage structures, and endanger human life. The U.S. Geological Survey’s Landslide Hazards Program is participating in a multi-agency cooperative effort to investigate debris flows in burned areas of southern California and other parts of the western United States. Participating agencies are the USDA Forest Service, the Natural Resources Conservation Service, and the California, Colorado, and Montana Geological Surveys. The objective of this project is to develop methods needed to estimate the locations, probability of occurrence, and size of potentially destructive debris flows. Public officials can use this information to plan and execute emergency response and post-fire rehabilitation. Analysis of data collected from studies of debris flows following wildfires can answer many of the questions fundamental to post-fire hazard assessments— what and why, where, when, how big, and how often?

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USGS2005

Determination of total mercury in biological and geological samples

The analytical chemist is faced with several challenges when determining mercury in biological and geological materials. These challenges include widespread mercury contamination, both in the laboratory and the environment, possible losses of mercury during sample preparation and digestion, the wide range of mercury values commonly observed, ranging from the low nanogram per gram or per liter for background areas to hundreds of milligrams per kilogram in contaminated or ore-bearing areas, great matrix diversity, and sample heterogeneity1. These factors can be naturally occurring or anthropogenic, but must be addressed to provide a precise and accurate analysis. Although there are many instrumental methods available for the successful determination of mercury, no one technique will address all problems or all samples all of the time. The approach for the determination of mercury used at the U.S. Geological Survey, Crustal Imaging and Characterization Team, Denver Laboratories, utilizes a suite of complementary instrumental methods when approaching a study requiring mercury analyses. Typically, a study could require the analysis of waters, leachates or selective digestions of solids, vegetation, and biological materials such as tissue, bone, or shell, soils, rocks, sediments, coals, sludges, and(or) ashes. No one digestion or sample preparation method will be suitable for all of these matrices. The digestions typically employed at our laboratories include: (i) a closed-vessel microwave method using nitric acid and hydrogen peroxide, followed by digestion/dilution with a nitric acid/sodium dichromate solution, (ii) a robotic open test-tube digestion with nitric acid and sodium dichromate, (iii) a sealed Teflon? vessel with nitric acid and sodium dichromate, (iv) a sealed glass bottle with nitric acid and sodium dichromate, or (v) open test tube digestion with nitric and sulfuric acids and vanadium pentoxide. The common factor in all these digestions is that they are very oxidative to ensure the conversion of all mercury forms into Hg (II). Each method of digestion has its advantages and limitations. The method of detection used in our laboratories involves a combination of an in-house, custom, classic continuous-flow cold-vapor atomic absorption spectrometry (CVAAS), a commercially available, automated, flow-injection and a continuous flow cold-vapor atomic fluorescence spectrometry (CV-AFS) systems, and a relatively new, automated and integrated approach where solid or liquid samples are thermally decomposed under an oxygen atmosphere (a nitrogen atmosphere is used for coals) and the released mercury vapor trapped onto a gold gauze and then thermally released into an AAS system. Other less frequently used instrumental methods available for the determination of mercury include inductively coupled plasma ? optical emission spectrometry (ICP-OES), inductively couple plasma ? mass spectrometry (ICP-MS) (both solution nebulization and laser ablation), and instrumental neutron activation analysis (INAA). Results from two case studies involving the determination of mercury in the challenging matrices of biological materials will be presented. These will include fillet, liver and stomach-content samples from grayling for a baseline/background study in Alaska, and samples of meat tissue and shell material from Tanner crabs from Glacier Bay, Alaska. These studies show that the method of digestion is more important than a very sensitive detection limit for mercury.

Open-File Report↗