Released October 04, 2023 11:45 EST

2023, Open-File Report 2023-1059

Gregory J. Walsh, Margaret A. Thomas, Robert G. Marvinney, Stephen B. Mabee, Frederick H. Chormann, Andrew Kozlowski, Marjorie H. Gale, Jon Kim, Brian Savage

Complexly deformed igneous, metamorphic, and sedimentary rocks form the bedrock of the Northeast region of the United States. Variably thick unconsolidated sediments deposited by glacial, fluvial, and eolian systems locally cover the bedrock. New geologic mapping focuses on areas lacking modern, detailed studies or syntheses, and contributes to existing framework research. This report addresses plans for the continued development of regionally and nationally consistent geologic maps and map databases, efforts to answer outstanding geologic questions, and societal concerns associated with related geologic topics, such as hazards, geologic and hydrologic resources, and environmental issues.

Released October 03, 2023 07:29 EST

2023, The Journal of Wildlife Management

Nathaniel R. Bowersock, Andrea R. Litt, Michael A. Sawaya, Kerry A. Gunther, Frank T. van Manen

The quality and availability of resources are known to influence spatial patterns of animal density. In Yellowstone National Park, relationships between the availability of resources and the distribution of grizzly bears (Ursus arctos) have been explored but have yet to be examined in American black bears (Ursus americanus). We conducted non-invasive genetic sampling during 2017–2018 (mid-May to mid-July) and applied spatially explicit capture-recapture models to estimate density of black bears and examine associations with landscape features. In both years, density estimates were higher in forested vegetation communities, which provide food resources and thermal and security cover preferred by black bears, compared with non-forested areas. In 2017, density also varied by sex, with female densities being higher than males. Based on our estimates, the northern range of Yellowstone National Park supports one of the highest densities of black bears (20 black bears/100 km²) in the northern Rocky Mountains (6–12 black bears/100 km² in other regions). Given these high densities, black bears could influence other wildlife populations more than previously thought, such as through displacement of sympatric predators from kills. Our study provides the first spatially explicit estimates of density for black bears within an ecosystem that contains the majority of North America's large mammal species. Our density estimates provide a baseline that can be used for future research and management decisions of black bears, including efforts to reduce human–bear conflicts.

Released October 03, 2023 07:10 EST

2023, Journal of Sea Research (196)

Darwin Ockerman, Douglas James Schnoebelen, Jack Poleykett, Patrick L. Friend, Coraggio K. Maglio, Kristina Boburka

During August 2018 – November 2019, the transport pathways of dredge material from a specially constructed nearshore feeder berm were investigated as part of a collaborative study by the City of South Padre Island, U.S. Army Corps of Engineers–Galveston District, U.S. Geological Survey, Partrac GeoMarine Inc., and Texas A&M University, into the efficacy of beneficial use dredge material (BUDM) as a method of replenishing the beach profile and shoreface at South Padre Island, Texas with sediment. Dual-signature (fluorescent and ferrimagnetic) tracer particles, designed to be hydraulically equivalent to the dredge material, were placed on the berm, and a sampling program was initiated to monitor the spatiotemporal movement of tracer particles under the influence of the prevailing hydrodynamic regime. Wave and current data were collected and were used together with available metocean data to identify the forcing mechanisms of sediment transport; improved understanding garnered from the consideration of multiple datasets can be used to inform future coastal management decisions.

Tracer analysis results indicated low magnitude, shoreward transport of dredge material from the berm and along shore transport in both northerly and southerly directions. Small amounts of tracer detected in beach face samples demonstrated connectivity between the constructed feeder berm and the shoreface. However, the generally low tracer concentration within beach face samples indicated low rates of sediment transport for berm sediments, and a low magnitude sediment transport pathway from the berm directly to the beach face, with possible storage of sediment in the nearshore bar system.

Given that the berm was at or beyond the closure depth and considering the relatively weak prevailing near bottom hydrodynamic conditions, the potential for sediment to be mobilized and transported during the study period was generally low. Periods of higher energy waves, driven by north-northwest winds, were identified as a key driver of sediment transport but due to the infrequent nature of these events the sediment transport regime across the area of interest was temporally limited. Longshore movement of sediment was both north and south, mainly dependent on prevailing wind directions and resulting longshore currents.

We discuss implications for coastal zone management and the use of feeder berms as an artificial beach nourishment mechanism to replenish sediments lost by coastal erosional processes. The insight into nearshore emplacement of material can be used by local governments and coastal managers to optimize the efficacy of berm emplacement and implement such schemes as a cost-effective nourishment option, or when onshore placement of material is not feasible.

Released October 02, 2023 07:22 EST

2023, Environmental Monitoring and Assessment (195)

Jennifer C. Murphy, Lindsey Ayn Schafer, Scott Mize

Released October 01, 2023 13:00 EST

2023, Journal of Volcanology and Geothermal Research (442)

Elske de Zeeuw-van Dalfsen, Michael P. Poland

Detection of gravity change over time has been used to better understand magmatic activity at volcanoes for decades, but the technique is not commonly applied to forecasting eruptions. In contrast, other tools, notably seismic, deformation, and gas monitoring have made exceptional strides in the past several decades and form the foundation for eruption forecasting, especially during the final buildup to an eruption. Reasons for this gap include the high cost and fragile nature of gravity instruments, and the ambiguous nature of many results. But this is changing. Instrumentation is becoming more robust and accurate, expenses may soon diminish thanks to technological advances, and the record of success in tracking subsurface mass change (either from magma or hydrothermal fluids) in volcanic areas is growing. Here we review how gravity change can be applied to forecasting volcanic eruptions across a variety of spatial and temporal scales. We argue that microgravity has untapped potential as a forecasting tool in three specific ways: constraining probabilistic assessments, detecting long-term mass change that may occur prior to the onset of vigorous seismicity and deformation, and identifying transient activity that indicates magma ascent or other changes that immediately precede new eruptions or changes in ongoing eruptions. As with any volcano-monitoring method, microgravity has strengths and weaknesses, but the varied forms of data collection—for instance, campaign versus continuous, and relative versus absolute—offer the potential to record a broad range of signals at volcanoes with a diversity of magmatic systems. The technique is currently underutilized; additional attention, investment, and application at more volcanoes could help to realize its promise.

Released September 30, 2023 06:57 EST

2023, Environmental Monitoring and Assessment (195)

Christopher Konrad, Scott W. Anderson

Released September 29, 2023 15:20 EST

2023, Scientific Investigations Report 2023-5090

Scott A. Olson

Current methods for determining the 1-percent annual exceedance probability (AEP) for a streamflow assume stationarity (the assumption that the statistical distribution of data from past observations does not contain trends and will continue unchanged in the future). This assumption allows the 1-percent AEP to be determined based on historical streamflow records. However, the assumption of stationarity is challenged by observed trends in streamflow records.

In response, the U.S. Geological Survey, in cooperation with the Federal Emergency Management Agency, studied potential changes to the 1-percent AEP streamflows at streamgages in the Housatonic River watershed in Massachusetts, Connecticut, and New York. The study used the Precipitation-Runoff Modeling System—a deterministic hydrologic model. Climate inputs to the model of temperature and precipitation were scaled to anticipated changes based on global climate models that could occur in 2030, 2050, and 2100. The model outputs were used to characterize the 1-percent AEP streamflows for 2030, 2050, and 2100 and compare the results to baseline conditions for 1950 to 2015. Results indicated that the 1-percent AEP streamflow for unregulated streams and rivers may increase from the 1950–2015 baseline period by 7.7, 11.7, and 17.3 percent in 2030, 2050, and 2100, respectively, because of climate change.

Released September 29, 2023 13:52 EST

2023, Open-File Report 2023-1067

Joshua T. Ackerman, C. Alex Hartman, Mark P. Herzog

The San Francisco Bay supports thousands of breeding waterbirds annually and hosts large populations of American avocets (Recurvirostra americana), black-necked stilts (Himantopus mexicanus), and Forster’s terns (Sterna forsteri). These three species have relied largely on former commercial salt ponds in South San Francisco Bay, which provide wetland foraging habitat and island nesting habitat. The South Bay Salt Pond Restoration Project is in the process of restoring 50–90 percent of 15,100 acres of these former salt ponds to tidal marsh and tidal mudflats. Although this restoration is expected to have numerous benefits, including providing habitat for tidal wetland-dependent species, improving water quality, buffering against storm surge, and protecting inland areas from sea level rise, the reduction in former salt pond habitat and nesting islands may negatively affect breeding waterbirds. To address the reduction in former salt pond habitat available to waterbirds, the South Bay Salt Pond Restoration Project also includes enhancements to remaining pond habitat, such as the construction of new islands for nesting. Moreover, the South Bay Salt Pond Restoration Project follows an adaptive management plan in which waterbird response to the changing landscape is monitored over time to ensure that existing breeding waterbird populations are maintained. In this report, we provide results of waterbird nest monitoring in South San Francisco Bay during the 2022 breeding season and present these results in the context of annual nest monitoring in South San Francisco Bay since 2005. Overall, nest abundance in 2022 remained at or near 18-year lows for American avocets (176 nests) and black-necked stilts (97 nests), but Forster’s tern nest abundance (1,727 nests) was at an 18-year high, reversing historically low abundance observed during 2015–2017. In 2022, there were only 6 American avocet, 4 black-necked stilt, and 4 Forster’s tern major colony nesting sites, which is down from annual averages of 12.4, 6.6, and 6.6 observed during 2005–2009. Nest success (30 percent for American avocets, 29 percent for black-necked stilt, and 53 percent for Forster’s terns) was below the 2005–2007 baseline values established for the South Bay Salt Pond Restoration Project. Average egg-hatching success (98 percent, 100 percent, and 90 percent), and clutch sizes (3.68, 3.70, and 2.63 eggs) of American avocets, black-necked stilts, and Forster’s terns, respectively, were similar to values observed during 2005–2010. All three species displayed notable shifts in nest initiation dates in 2022, with American avocets and Forster’s terns nesting 10–11 days earlier and black-necked stilts nesting 10 days later than during 2005–2010. Finally, the enhanced, managed ponds with newly constructed islands (Ponds A16 and SF2) supported 86 percent of all the Forster’s tern nests recorded in South San Francisco Bay in 2022, which is the first time these managed ponds have hosted such a substantial number of tern nests.

Released September 29, 2023 11:05 EST

2023, Open-File Report 2023-1079

Logan M. Maxwell, Elisabeth C. Teige, Samuel E. Jordan, Tait K. Rutherford, Ella M. Samuel, Lea B. Selby, Alison C. Foster, Nathan J. Kleist, Sarah K. Carter

Integrating recent scientific knowledge into management decisions supports effective natural resource management and can lead to better resource outcomes. However, finding and accessing scientific knowledge can be time consuming and costly. To assist in this process, the U.S. Geological Survey is creating a series of annotated bibliographies on topics of management concern for western lands. Previously published reports introduced a methodology for preparing annotated bibliographies to facilitate the integration of recent, peer-reviewed science into resource management decisions. Therefore, relevant text from those efforts is reproduced here to frame the presentation. Centrocercus minimus (Gunnison sage-grouse; hereafter GUSG) has been a focus of scientific investigation since the early 2000s. The U.S. Fish and Wildlife Service listed GUSG as threatened under the Endangered Species Act in 2014 because of declining populations and increasing habitat loss. The U.S. Fish and Wildlife Service, Bureau of Land Management, and Colorado Parks and Wildlife have sought to increase the conservation of this species by adapting management and recovery plans to reduce threats and increase population resiliency. GUSG are studied less than the closely related Centrocercus urophasianus (greater sage-grouse); however, research efforts have recently increased to understand the life history, genetics, and habitat suitability of this sagebrush-obligate species. We compiled and summarized peer-reviewed journal articles, data products, and formal technical reports (such as U.S. Department of Agriculture Forest Service General Technical Reports and U.S. Geological Survey Open-File Reports) on GUSG, published between January 2005 and September 2022. We first systematically searched three reference databases and three government databases using the following search phrases: “Gunnison sage-grouse” or “lesser sage-grouse” or “Gunnison grouse” or “Gunnison sage grouse” or “lesser sage grouse” or “Centrocercus minimus.” We refined the initial list of products by removing (1) duplicates, (2) publications that were not published as research, data products, or scientific review articles in peer-reviewed journals or as formal technical reports, and (3) products that did not have GUSG as a research focus or products that did not present new data or findings about GUSG. We summarized each product using a consistent structure (background, objectives, methods, location, findings, and implications) and identified the management topics (for example, population estimates or targets, habitat, and management efforts) addressed by each product. We also noted which publications included new geospatial data. The review process for this annotated bibliography included two initial internal colleague reviews of each summary, requesting input on each summary from an author of the original publication, and a formal peer review. Our initial searches resulted in 80 total products, of which 63 met our criteria for inclusion of which 53 were products that had not been summarized before. Across products summarized in the annotated bibliography, broad-scale habitat characteristics; population estimates or targets; behavior or demographics; and genetics were the most commonly addressed management topics. The bibliographies are available on the Science for Resource Managers tool (https://apps.usgs.gov/science-for-resource-managers) and are searchable by topic, location, and year, and the search tool includes links to each original publication. The studies compiled and summarized in this annotated bibliography may inform planning and management actions that seek to maintain and restore sagebrush landscapes and GUSG populations across the GUSG range.

Released September 29, 2023 09:18 EST

2023, Scientific Investigations Report 2023-5107

Stephen B. Gingerich, Daniel R. Wise, Adam J. Stonewall

The U.S. Geological Survey, in cooperation with the Oregon Department of Transportation (ODOT), evaluated the effects of cold-weather chloride deicers (road deicing chemicals) on groundwater quality, with a focus on chloride, near the Siskiyou Pass in southwestern Oregon. The study covered the period during July 2018 through February 2021. Between the years 2016 and 2020 ODOT applied up to 16,000 gallons per mile of chloride deicer and 143,000 pounds per mile of road salt along an 11-mile stretch of Interstate 5 (I-5) through the Siskiyou Pass. Despite the benefit of safer driving conditions, there are potentially negative environmental effects associated with the use of chloride-based deicers (such as magnesium chloride and sodium chloride). The results from this study are intended to help ODOT assess the water-quality effects from the application of chloride deicers at the Siskiyou Pass and inform decisions on how those chemicals are used.

Dissolved chloride concentrations tended to be greater in groundwater downgradient from I-5 compared to groundwater upgradient from the interstate. Specific conductance was a good predictor of dissolved chloride concentration (R² = 0.905). Continuous monitoring showed that specific conductance measurements were greater at four downgradient spring-fed sites at the end of the study period compared with measurements at the beginning of the study. The study results indicate that chloride levels in shallow groundwater downgradient from I-5 are increasing, but dissolved chloride concentrations in domestic wells are not above the U.S. Environmental Protection Agency drinking water recommendations. The approach and methods used in this study, with modifications as site conditions warrant, can be applied in other areas of chloride deicer application to determine if groundwater is affected.

Released September 28, 2023 12:49 EST

2023, Scientific Investigations Report 2023-5022

Adam G. Johnson, Alan Mair, Delwyn S. Oki

Johnson, A.G., Mair, A., and Oki, D.S., 2023, Identifying the relative importance of water-budget information needed to quantify how land-cover change affects recharge, Hawaiian Islands: U.S. Geological Survey Scientific Investigations Report 2023–5022, 28 p., https://doi.org/10.3133/sir20235022.

This report describes a sensitivity analysis of a water-budget model that was completed to identify the most important types of hydrologic information needed to reduce the uncertainty of model recharge estimates. The sensitivity of model recharge estimates for the Hawaiian Islands of Oʻahu and Maui was analyzed for seven model parameters potentially affected by land-cover changes within a watershed. The seven model parameters tested were canopy capacity, canopy-cover fraction, crop coefficient, fog-catch efficiency, root depth, stemflow, and trunk-storage capacity.

Results of the sensitivity analysis were used to (1) quantify the relative importance of the seven model parameters to recharge assessments for three moisture zones (dry, mesic, and wet) on Oʻahu and Maui and (2) prepare a list of critical information needs for each moisture zone. The list of critical information needs was developed for three general types of land cover (forest, shrubland, and grassland) that are assumed to be affected by watershed management in the Hawaiian Islands. Identified information needs included estimates or measurements of (1) evapotranspiration processes needed to determine crop coefficients for land-cover types in all moisture zones, (2) rooting depths for land-cover types in the dry and mesic moisture zones, (3) canopy-cover fraction for forests in the wet and mesic moisture zones, (4) ratios of fog interception to rainfall for forests and shrublands in the wet moisture zone, and (5) canopy capacity for forests in the wet and mesic moisture zones. The list of information needs can guide data-collection strategies of future projects. Collection and analysis of the identified hydrologic information may help model users develop a better parameterization scheme, reduce uncertainty of values that model users assign to land-cover dependent parameters, and therefore allow future applications of the water-budget model to more accurately quantify how recharge in the Hawaiian Islands might be affected by future land-cover changes within a watershed.

Released September 28, 2023 11:19 EST

2023, Scientific Investigations Report 2023-5096

Stephen A. Hundt, James R. Bartolino

Most of the population of the Treasure Valley and the surrounding area of southwestern Idaho and easternmost Oregon depends on groundwater for domestic supply, either from domestic or municipal-supply wells. Current and projected rapid population growth in the area has caused concern about the long-term sustainability of the groundwater resource. In 2016, the U.S. Geological Survey, in cooperation with the Idaho Water Resource Board and the Idaho Department of Water Resources, began a project to construct a numerical groundwater-flow model of the westernmost portion of the western Snake River Plain aquifer system, called the Treasure Valley.

The development of the model was guided by several objectives, including:

1. to improve the understanding of groundwater and surface water interactions;
2. to facilitate conjunctive water management;
3. to provide a tool for water resources planning; and
4. to provide a tool for water allocation.

The model was constructed with a spatial scale and level of detail that aimed to meet these objectives while balancing the sometimes-competing goals of fast runtimes, numerical stability, usability, and parsimony.

The Treasure Valley Groundwater Flow Model (TVGWFM) is a three-dimensional finite-difference numerical model constructed using MODFLOW 6 (Langevin and others, 2017, Documentation for the MODFLOW 6 Groundwater Flow Model: U.S. Geological Survey Techniques and Methods, book 6, chap. A55, 197 p., https://doi.org/10.3133/tm6A55). The model covers the westernmost portion of the western Snake River Plain and is discretized into a regular grid of 64 by 65 cells with a side length of 1 mile and 6 layers of varying depth and active area. A historical model period was developed consisting of 360 month-long stress periods for 1986–2015. The model builds upon previous modeling efforts by adding a transient period, incorporating new head and discharge observations to constrain parameters, incorporating information from the hydrogeologic framework model (HFM) of Bartolino (2019, Hydrogeologic framework of the Treasure Valley and surrounding area, Idaho and Oregon: U.S. Geological Survey Scientific Investigations Report 2019–5138, https://doi.org/10.3133/sir20195138) and incorporating refined estimates of evapotranspiration and irrigation classification of lands in the study area.

The TVGWFM includes all significant components of recharge to and discharge from the aquifer. Inflows include canal seepage, irrigation and precipitation recharge, mountain-front recharge, rivers and stream seepage, and seepage from Lake Lowell. Outflows include discharge to agricultural drainage ditches, discharge to rivers and streams, pumping, and discharge to Lake Lowell. Each recharge or discharge component is represented separately using individual MODFLOW 6 packages.

Parameter values were derived with a combination of trial-and-error steps and automated parameter estimation using PEST software (Doherty, J.E., 2005, PEST, model-independent parameter estimation–User manual: Watermark Numerical Computing, https://pesthomepage.org/documentation). Parameter estimates were constrained with several types of observation data, including water levels, water level changes, vertical water level differences, drain discharges, change in drain discharges, river seepage, seepage from Lake Lowell, and change in seepage from Lake Lowell. Material properties from the hydrogeologic framework were also used to assign the minimum and maximum values of some parameters.

A final parameter realization was reached that minimized residuals between the observed and modelled values for the various observation groups. Mean residuals for the observation groups were 15.4 feet (ft) for water levels, 0.2 ft for water level changes, 19.4 ft for vertical water level differences, −3.9 cubic feet per second (ft³/s) for drain discharges, 0.0 ft³/s for changes in drain discharge, 45.0 ft³/s for river seepage, −40.1 ft³/s for Lake Lowell seepage, and 126.3 ft³/s for changes in Lake Lowell seepage. The quality of the model’s fit to observations varied spatially, with notable areas of under- or over-simulation of water levels present to the northwest and southwest of Lake Lowell, in the foothills along the eastern model boundary, and near the City of Eagle. Trends were observed in the residuals of many of the observation groups, indicating that the model is missing or not fully reproducing some phenomena that are observed in the system.

The TVGWFM can be used as a tool for water resource planning, for understanding the interactions of groundwater and surface water at a basin scale, and for facilitating conjunctive management, but may lack the precision needed for water rights administration at a local scale. Additional sources of uncertainty or limitations of the model are noted. The quantity and spatial distribution of canal seepage and infiltration of irrigation water recharge, the largest sources of recharge to the system, are unknown and approximated indirectly. There is poor understanding of how canal seepage and incidental recharge change as land is converted from agricultural (irrigated) to suburban (semi-irrigated). These uncertainties will affect any scenarios that investigate changes to land use or irrigation practices. Finally, the model has relatively high water-level residuals around and to the southwest of Lake Lowell and should not be used to estimate water level effects in that region.

The model was built with multiple, broadly expressed objectives and did not optimize performance for specific uses. However, the model and the tools included in an associated data release provide ample flexibility to improve the model for future uses. Adjustments and improvements could be made by refining the model in an area of interest, collecting additional calibration data, applying more rigorous boundary conditions, or re-estimating model parameters to optimize model performance for a specific model forecast.

Released September 28, 2023 11:09 EST

2023, Scientific Investigations Report 2023-5103

Anna M. Nottmeier, Katherine J. Knierim, Phillip D. Hays

The Sparta-Memphis aquifer, present across much of eastern Arkansas, is the second most used groundwater resource in the State, with the Mississippi River Valley alluvial aquifer being the primary groundwater resource. The U.S. Geological Survey, in cooperation with Arkansas Department of Agriculture-Natural Resources Division, Arkansas Geological Survey, Natural Resources Conservation Service, Union County Water Conservation Board, and the Union County Conservation District, collects groundwater data across the Sparta-Memphis aquifer extent in Arkansas. This report presents water-level data for measurements conducted during two time periods, January–May 2013 and January–June 2015, and discusses water-level altitude changes for the 2011–13 and 2013–15 periods in the Sparta-Memphis aquifer. Accompanying water-level data in this report include groundwater-quality data for the period 2010–15 in the Sparta-Memphis aquifer. Groundwater data can guide ongoing and future groundwater-monitoring efforts and inform management of the aquifers in Arkansas.

Water levels measured at 306 wells from January to May 2013 and 273 wells from January to June 2015 are graphically presented as potentiometric-surface maps. Measurements from 2011, 2013, and 2015 were used in the construction of 2011–13 and 2013–15 water-level change maps. Select long-term hydrographs are included in the report to illustrate water-level changes at the local scale.

Water-level data show the influence of climate, pumping, and conservation and management efforts on groundwater levels. With respect to climate, the study area experienced extreme drought conditions between January 2011 and December 2012. The proximate effects of drought—increased evapotranspiration, decreased recharge, and increased irrigation needs—resulted in water-level declines that were particularly notable in the northern and central portions of the study area.

Groundwater sampled in 2010–15 from 148 wells completed in the Sparta-Memphis aquifer was analyzed for specific conductance, pH, chloride (Cl) concentration, and bromide (Br) concentration. In 2015, groundwater-quality data from 103 wells completed in the Sparta-Memphis aquifer had a median specific conductance of 356 microsiemens per centimeter at 25 degrees Celsius and a median Cl concentration of 9.5 milligrams per liter (mg/L). The data show two areas of higher Cl (greater than 10 mg/L) and higher Br (greater than 0.5 mg/L) concentrations in Union, Calhoun, and Bradley Counties in southern Arkansas and Monroe and Phillips Counties in eastern-central Arkansas. A Cl and Br mixing model indicates the two regions of wells may have different sources of higher salinity. In the greater Union County area, water in most wells may be a mixture of recharge or precipitation and higher salinity groundwater from the Nacatoch aquifer. Water in wells in eastern-central Arkansas may be sourced from aquifers having a higher Cl concentration (and thus, also a higher Cl-to-Br ratio).

Released September 28, 2023 06:40 EST

2023, ICES Journal of Marine Science

Maya Groner, Eliana D. Bravo-Mendosa, Ashley MacKenzie, Jacob L. Gregg, Carla M. Conway, John T. Trochta, Paul Hershberger

Causes of population collapse and failed recovery often remain enigmatic in marine forage fish like Pacific herring (Clupea pallasii) that experience dramatic population oscillations. Diseases such as ichthyophoniasis are hypothesized to contribute to these declines, but lack of long-term datasets frequently prevents inference. Analysis of pathogen surveillance and population assessment datasets spanning 2007–2019 indicate that the age-based prevalence estimate of Ichthyophonus infection was, on average, 54% greater among a collapsed population of Pacific herring (Prince William Sound, Alaska, USA) as compared to a nearby population (Sitka Sound, Alaska, USA) that is relatively robust. During the study years, the age-based infection prevalence ranged from 14 to 44% in Prince William Sound and 5 to 33% in Sitka Sound. At both sites, the age-based infection prevalence declined over time, with an average decrease of 7% per year. Statistical analyses indicated that infection prevalence between the two populations was reduced by regional factors affecting both sites, and that these factors were independent of herring density. Infection prevalence in both populations was positively correlated with herring age and negatively correlated with the Pacific Decadal Oscillation. This study demonstrates how synthesis of environmental, stock assessment, and disease assessment data can be leveraged to elucidate epidemiological trends in diseases of wild fish.

Released September 27, 2023 14:00 EST

2023, Open-File Report 2023-1069

Madison Langseth, Elizabeth Sellers, Grace C. Donovan, Amanda N. Liford

As of 2016, the U.S. Geological Survey (USGS) Fundamental Science Practices require data management plans (DMPs) for all USGS and USGS-funded research. The USGS Science Data Management Branch of the Science Analytics and Synthesis Program has been working to help the USGS (Bureau) meet this requirement. However, USGS researchers still encounter common data management-related challenges that may be reduced or eliminated by better planning. In 2021, USGS staff were given a series of surveys aimed to better understand current data management planning practices, perceptions, and needs. The survey results indicated that adoption and integration of data management planning and DMPs into USGS research project workflows are broad, if inconsistent, across USGS Science Centers and programs. The USGS Science Data Management Branch can help improve clarity and guidance on the purpose, intended audience, content, workflows, and evaluation processes for DMPs. It would also be beneficial to provide additional supporting cyberinfrastructure to support DMP activities. Survey responses indicated it would be beneficial for the Science Data Management Branch to develop a strategy, other than through DMPs, for teaching and encouraging good data management practices. Although these surveys were an opportunity for USGS staff to provide feedback on their experiences, the surveys may also have revealed the desire for more frequent evaluations, cross-disciplinary communication, and training on research data management and DMP development and integration, in the context of USGS policy, Fundamental Science Practices requirements, and overall Bureau expectations. Data management-related roles such as data manager or steward, information technologist, and repository manager may need to be formally recognized as skilled professional career positions within the Bureau. At a minimum, the best practice for USGS would be to create and maintain DMPs as living documents, integrated with existing systems that are broadly accessible to all stakeholders, and include quantitatively measurable benefits tied directly to a clearly defined purpose.

Released September 27, 2023 12:02 EST

2023, Scientific Investigations Map 3509

Scott D Ducar, Lauren M. Zinsser

The U.S. Geological Survey and the Idaho Department of Water Resources measured groundwater levels during spring 2022 and autumn 2022 to create detailed potentiometric-surface maps for the alluvial aquifer in the Big Lost River Valley in south-central Idaho. Wells were assigned to shallow, intermediate, and deep water-bearing units based on well depth, groundwater potentiometric-surface altitude, and hydrogeologic unit. Potentiometric-surface contours were created for each of the three water-bearing units for spring 2022 and autumn 2022. Groundwater flow generally follows topography down valley to the south. The groundwater-level data also were used to calculate changes in groundwater levels from spring to autumn 2022 and from historical measurement events in 1968 and 1991 to 2022. Groundwater levels declined at most wells from spring 1968 to spring 2022 and from spring 1991 to spring 2022. Although groundwater-level changes are sensitive to interannual wet and dry periods, long-term groundwater-level declines suggest that recharge and down-valley groundwater flows are insufficient to fully recover groundwater-level declines from pumping in some parts of the alluvial aquifer in the Big Lost River Valley.

Released September 26, 2023 15:06 EST

2023, Scientific Investigations Report 2023-5001

Namjeong Choi

In 2021, the U.S. Geological Survey (USGS), in cooperation with the Bandera County River Authority and Groundwater District and the Texas Water Development Board, studied floods to produce a library of flood-inundation maps for the Sabinal River near Utopia, Texas. Digital flood-inundation maps were created for a 10-mile reach of the Sabinal River from USGS streamgage 08197936 Sabinal River below Mill Creek near Vanderpool, Tex., at the upstream boundary of the study reach, to USGS streamgage 08197970 Sabinal River at Utopia, Tex. (hereinafter referred to as the “Utopia gage”), at the downstream boundary of the study reach, and for a 7-mile reach of the West Sabinal River. The flood-inundation maps depict estimates of the areal extent and depth of flooding corresponding to selected gage heights (the water-surface elevation at a streamgage, commonly referred to as “stage”) at the Utopia gage. Water-surface elevations were computed for the stream reach by means of a two-dimensional unsteady-state diffusion wave model with the U.S. Army Corps of Engineers Hydrologic Engineering Center River Analysis System program. A synthetic stage-discharge rating curve at the Utopia gage was developed using a regional regression equation to construct the model boundary condition inputs, and the upper bound of the stage-discharge relation was matched to a major flood event in July 2002. The hydraulic model was used to compute water-surface elevations for 35 stages at 0.5-foot (ft) increments referenced to the Utopia gage datum and ranging from 11 ft (near bankfull) to 28 ft (estimated peak stage during the July 2002 flood event). These flood-inundation maps, in conjunction with the real-time stage data from the Utopia gage, are intended to help guide the public in taking individual safety precautions and provide emergency management personnel with a tool to efficiently manage emergency flood operations and postflood recovery efforts.

Released September 26, 2023 14:49 EST

2023, Open-File Report 2023-1075

Md. Obaidul Haque, Rajagopalan Rengarajan, Mark Lubke, Md Nahid Hasan, Ashish Shrestha, Fatima Tuz Zafrin Tuli, Jerad L. Shaw, Alex Denevan, Shannon Franks, Kathryn Ruslander, Esad Micijevic, Michael J. Choate, Cody Anderson, Kurt Thome, Ed Kaita, Julia Barsi, Raviv Levy, Jeff Miller, Leibo Ding

Executive Summary

The U.S. Geological Survey Earth Resources Observation and Science Calibration and Validation (Cal/Val) Center of Excellence (ECCOE) focuses on improving the accuracy, precision, calibration, and product quality of remote-sensing data, leveraging years of multiscale optical system geometric and radiometric calibration and characterization experience. The ECCOE Landsat Cal/Val Team continually monitors the geometric and radiometric performance of active Landsat missions and makes calibration adjustments, as needed, to maintain data quality at the highest level.

This report provides observed geometric and radiometric analysis results for Landsats 7–8 for quarter 2 (April–June) of 2023. All data used to compile the Cal/Val analysis results presented in this report are freely available from the U.S. Geological Survey EarthExplorer website: https://earthexplorer.usgs.gov.

One specific activity that the ECCOE Landsat Cal/Val Team closely monitored was a Landsat 8 Thermal Infrared Sensor (TIRS) Scene Select Mechanism (SSM) excursion anomaly. On April 21, 2023, a TIRS SSM excursion error flag was indicated in telemetry during a calibration activity when the SSM encoder was powered on and the mirror was between the nadir position and the deep space position. An initial recovery plan indicated the SSM was moving erratically, so the instrument was put into a safe state for additional troubleshooting. A second recovery plan was developed and successfully executed on April 23, 2023. Additional information about the Landsat 8 TIRS SSM excursion anomaly is available at https://www.usgs.gov/landsat-missions/news/landsat-8-level-1-product-processing-resumes.

Released September 26, 2023 11:15 EST

2023, Journal of Big Data (10)

Samantha Arundel, Kevin G McKeehan, Bryan B Campbell, Andrew N. Bulen, Philip T. Thiem

Many agencies and organizations, such as the U.S. Geological Survey, handle massive geospatial datasets and their auxiliary data and are thus faced with challenges in storing data and ingesting it, transferring it between internal programs, and egressing it to external entities. As a result, these agencies and organizations may inadvertently devote unnecessary time and money to convey data without existing or outdated standards. This research aims to evaluate the components of data conveyance systems, such as transfer methods, tracking, and automation, to guide their improved performance. Specifically, organizations face the challenges of slow dispatch time and manual intervention when conveying data into, within, and from their systems. Conveyance often requires skilled workers when the system depends on physical media such as hard drives, particularly when terabyte transfers are required. In addition, incomplete or inconsistent metadata may necessitate manual intervention, process changes, or both. A proposed solution is organization-wide guidance for efficient data conveyance. That guidance involves systems analysis to outline a data management framework, which may include understanding the minimum requirements of data manifests, specification of transport mechanisms, and improving automation capabilities.

Released September 26, 2023 10:49 EST

2023, Scientific Investigations Report 2023-5102

Mandy L. Stone, Brian J. Klager

The Equus Beds aquifer and Cheney Reservoir are primary sources for the city of Wichita’s current (2023) water supply. The Equus Beds aquifer storage and recovery (ASR) project was developed by the city of Wichita in the early 1990s to meet future water demands using the Little Arkansas River as an artificial aquifer recharge water source during above-base-flow conditions. Little Arkansas River water is removed from the river at an ASR Facility intake structure, treated using National Primary Drinking Water Regulations as a guideline, and is infiltrated into the Equus Beds aquifer through recharge basins or injected into the aquifer through recharge wells for later use. The U.S. Geological Survey, in cooperation with the city of Wichita, completed this study to quantify and characterize Little Arkansas River water-quality data. Data in this report can be used to evaluate changing conditions, provide science-based information for decision making, and help meet regulatory requirements.

Continuous (hourly) physicochemical properties were measured, and discrete water-quality samples were collected from three Little Arkansas River sites located along the easternmost extent of the Equus Beds aquifer during 1995 through 2021 over a range of streamflow conditions. The Little Arkansas River at Highway 50 near Halstead, Kansas, streamgage (U.S. Geological Survey station 07143672; hereafter referred to as the “Highway 50 site”) is located upstream from the other two sites, and the Little Arkansas River near Sedgwick, Kans., streamgage (U.S. Geological Survey station 07144100; hereafter referred to as the “Sedgwick site”) is located downstream from the other two sites; these two sites bracket most of the easternmost part of the Equus Beds aquifer. The Little Arkansas River upstream of ASR Facility near Sedgwick, Kans., streamgage (U.S. Geological Survey station 375350097262800; hereafter referred to as the “Upstream ASR site”) is located between the Highway 50 and Sedgwick sites, about 14.7 river miles (mi) downstream from the Highway 50 site, about 1.7 river mi upstream from the Sedgwick site, and immediately upstream from the ASR Facility intake structure. Surrogate models for water-quality constituents of interest (including bromide, dissolved organic carbon, 2-chloro-4-isopropylamino-6-amino-s-triazine [deethylatrazine], atrazine, and metolachlor) were updated or developed using continuously measured and concomitant discrete data. These surrogate models, along with previously developed regression models, were used to compute concentrations (at the Highway 50, Sedgwick, and Upstream ASR sites) and loads (at the Highway 50 and Sedgwick sites) during the study period. Federal criteria were used to evaluate water quality. Where applicable, water-quality data were compared to Federal national drinking-water regulations. Flow-normalized water-quality constituent trends were evaluated using Weighted Regressions on Time, Discharge, and Season (WRTDS) statistical models and water-quality trends were described using WRTDS bootstrap tests.

Continuously computed primary ion concentrations were generally larger at the Highway 50 site compared to the Sedgwick site. During the study period, the Federal secondary maximum contaminant level (SMCL) for dissolved solids was exceeded 57 percent of the time at the Highway 50 site and 38 percent of the time at the Sedgwick site. Computed bromide concentrations were larger at the Highway 50 site and exceeded the city of Wichita treatment threshold about 70, 21, and 19 percent of the time at the Highway 50, Sedgwick, and Upstream ASR sites, respectively. Chloride concentrations exceeded the Federal SMCL about 16 percent of the time at the Highway 50 site and did not exceed the SMCL at the Sedgwick site. Continuous arsenic concentrations exceeded the Federal Maximum Contaminant Level (MCL) 9 to 15 percent of the time at the Sedgwick and Highway 50 sites, respectively, during the study. Atrazine concentrations exceeded the Federal MCL 10 percent of the time at the Highway 50 and Sedgwick sites and 14 percent of the time at the Upstream ASR site during the study; computed glyphosate concentrations at the Sedgwick site never exceeded the MCL during the study.

Little Arkansas River flow-normalized primary ion concentrations during 1995 through 2021 generally had downward trends and decreases were generally larger at the Highway 50 site compared to the Sedgwick site. Dissolved solids and chloride concentrations decreased at the Highway 50 and Sedgwick sites. Bromide had no trend at the Highway 50 site and a downward trend at the Sedgwick site. Nitrate plus nitrite and total phosphorus concentrations had upward trends at the Highway 50 site but downward trends at the Sedgwick site, whereas total organic carbon had upward trends at both sites. Nitrate plus nitrite, total nitrogen, total phosphorus, and total organic carbon fluxes had upward trends at the Highway 50 and Sedgwick sites. Suspended-sediment concentrations had an upward trend at the Highway 50 site and had no trend at the Sedgwick site. Arsenic concentrations had downward trends at the Highway 50 and Sedgwick sites.

About one-quarter to one-half of the Little Arkansas River loads, including nutrients and sediment, were transported during 1 percent of the time during the study. Because streamflows are highly sensitive to climatic variation and an increase of extreme precipitation events in the Great Plains is expected, similar disproportionately large pollutant loading events may increase into the future. Continuous measurement of physicochemical properties in near-real time allowed characterization of Little Arkansas River surface water during conditions and time scales that would not have been possible otherwise and served as a complement to discrete water-quality sampling. Continuation of this water-quality monitoring will provide data to characterize changing conditions in the Little Arkansas River and possibly identify new and changing trends. Information in this report allows the city of Wichita to make informed municipal water-supply decisions using past and present water-quality conditions and trends in the watershed.

Released September 26, 2023 07:00 EST

2023, International Journal of Enviornmental Research and Public Health (20)

Anna Gitter, Kristina Mean, John T. Lisle

Released September 25, 2023 06:49 EST

2023, European Journal of Remote Sensing (TEJR) (56)

Neda Abbasi, Hamideh Nouri, Pamela L. Nagler, Kamel Didan, Sattar Chavoshi Borujeni, Armando Barreto-Muñoz, Christian Opp, Stefan Siebert

Released September 23, 2023 06:37 EST

2023, Journal of Volcanology and Geothermal Research (442)

T. Orr, Michael H. Zoeller, Edward W. Llewellin, Matthew R. Patrick

Released September 22, 2023 07:06 EST

2023, Science of Remote Sensing (8)

Christopher J. Crawford, David P. Roy, Saeed Arab, Christopher Barnes, Eric Vermote, Glynn Hulley, Aaron Gerace, Michael J. Choate, Christopher Engebretson, Esad Micijevic, Gail L. Schmidt, Cody Anderson, Martha Anderson, Michelle Bouchard, Bruce D. Cook, Ray Dittmeier, Danny Howard, Calli Jenkerson, Minsu Kim, Tania Kleyians, Tom Maiersperger, Chase Mueller, Christopher Neigh, Linda Owen, Benjamin Page, Nima Pahelvan, Rajagopalan Rengarajan, Jean-Claude Roger, Kristi Sayler, Pat L Scaramuzza, Sergii Skakun, Lin Yan, Hankui K. Zhang, Zhe Zhu, Stephen G. Zahn

Released September 22, 2023 06:59 EST

2023, The Journal of Wildlife Management

Jennifer Rowe, Christopher Pearl, Adam Duarte, Brome McCreary, Michael J. Adams

Released September 21, 2023 14:25 EST

2023, Open-File Report 2023-1042

Alexander R. Blanchette, Simon L. Klemperer, Walter D. Mooney

As part of a joint Saudi Geological Survey (SGS) and United States Geological Survey project, we analyzed P-wave receiver functions from seismic stations covering most of the Kingdom of Saudi Arabia to map the thickness of the crust across the Arabia Plate. We present an update of crustal thickness estimates and fill in gaps for the western Arabian Shield and the rifted margin at the Red Sea (the coastal plain), as well as the eastern Arabian Platform. We applied a conventional H-k stacking algorithm and included careful attention to stacking weights, two forms of sedimentary corrections for stations located on the Arabian Platform, and additional processing for noisy stations. We obtained useful results at 154 stations from 898 teleseismic events over a 2-year period from 1995–1997 (for non-SGS stations) and a 6-year period from 2008–2014 (for SGS stations). Average crustal thickness (that is, depth to the Mohorovičić discontinuity [Moho] below the surface) beneath the Red Sea coastal plain (the rift margin) is 29 kilometers (km), beneath the volcanic fields (known in Arabic as harra [plural] or harrat [singular]) is 35 km, beneath the Arabian Shield (excluding harrats) is 37 km, and beneath the Arabian Platform is 38 km. Crustal thinning appears not to extend east of the rift escarpment, suggesting uniform extension that is no broader at depth than at the surface. In contrast to some previous interpretations that the Arabian Platform crust is thicker than that of the Arabian Shield, we find no statistically significant difference between their whole crustal thicknesses. However, the average sub-sedimentary crustal thickness (that is, the crystalline crust) for stations on the Arabian Platform is 34 km, 3 km thinner than the crust of the Arabian Shield. Individual station P-wave (pressure) velocity and S-wave (shear) velocity ratios (VP/VS) are highly variable for the Arabia Plate, ranging from 1.60 to 1.97 and averaging 1.75, with a standard deviation of 0.07. There are no statistically significant differences between VP/VS ratios of the different geologic regions of Saudi Arabia. Similar VP/ VS ratios, coupled with similar crustal thicknesses for harrats and the Arabian Shield, indicate that Cenozoic magmatism has contributed negligibly to crustal growth.

Released September 21, 2023 09:12 EST

2023, Environmental Science & Technology Water

Jennifer S. Harkness, Patrick Michael McCarthy, Bryant Jurgens, Zeno Levy

The Indio subbasin of the Coachella Valley is a desert area of southern California where a growing population depends primarily on groundwater for drinking and agricultural uses. The aquifer system has been supplemented with Colorado River water through managed recharge and widespread irrigation since the mid-20th century. We use a combination of geochemical modeling and trend analysis to identify changes in total dissolved solids through time, elucidate the sources of dissolved solids, and quantify the extent of contributions from those sources throughout the Indio subbasin. We conclude that recharged Colorado River water is the primary source and driver of increasing salinity, particularly in areas immediately downgradient from the recharge locations and in the eastern part of the subbasin away from the recharge ponds due to irrigation using imported water. Other contributions of dissolved solids to groundwater resources include geothermal waters, wastewater effluent, and agricultural return flow, although their effects are more localized. This study presents a broadly applicable framework for identifying sources of dissolved solids in groundwater wells and salinity trends at a regional scale in a large data set.

Released September 21, 2023 07:20 EST

2023, Marine Ecologly Progressive Series (719) 92

Paul J. Rudershausen, Steven M. Lombardo, George R. Stilson, Matthew J. O'Donnell

Organisms that rely on salt marsh habitat are an important trophic link, helping to maintain estuarine ecosystem productivity. We used GIS to quantify intertidal (assumed salt marsh) area from aerial photographs taken in 1939 and from software-supplied satellite imagery taken in 2021 for tidal creeks in North Carolina (USA) that have experienced minor (<20%), moderate (20-60%), or substantial (>60%) losses of intertidal habitat over the 8 decades. The current (2022) absolute abundance of adult Fundulus heteroclitus, a trophically important resident fish in US Atlantic estuaries, was estimated over each season in each creek by fitting a Lincoln-Petersen model to tag-recapture data. Current abundances of F. heteroclitus were lowest in creeks with the lowest intertidal area. The median and 2.5/97.5 credible intervals of the posterior probability distribution for the slope of a regression model relating current fish abundance to current intertidal area were positive, demonstrating that intertidal area was a meaningful covariate of abundance. Loss of intertidal area in the creeks between 1939 and 2021 ranged from 8 to 93%. The correlation between current intertidal area and historical loss of this habitat was negative and significant (Pearson r = -0.91, p = 0.012). Parameters from the regression relating current abundance to intertidal area were used to estimate historic F. heteroclitus abundances in each creek using GIS-derived estimates of historic intertidal area. Historic abundances were predicted to have been on average (across study creeks) 7.5 times greater in 1939 than in 2022. Reduced abundances, and thus reduced trophic relay by F. heteroclitus to higher-order consumers, can be expected in estuaries that have lost salt marsh due to inter-decadal development.

Released September 21, 2023 07:00 EST

2023, Earth's Future (11)

Celina Balderas-Guzman, Kevin J. Buffington, Karen M. Thorne, Glenn R. Guntenspergen, Michelle A. Hummel, Mark T. Stacey

Released September 20, 2023 14:30 EST

2023, Fact Sheet 2023-3039

Justine Annaliese Neville, Glenn R. Guntenspergen

Introduction

Tidally influenced coastal wetlands, both saline and fresh, appear where terrestrial and marine environments meet and are considered important ecosystems for identifying the impacts of climate change. Coastal wetlands provide valuable benefits to society and the environment in the form of flood protection, water-quality improvements, and shoreline erosion reduction, making them one of the most important ecosystems in the world. Historically, these ecosystems have vertically adjusted to match rising sea levels through biologic and physical processes, but they are increasingly vulnerable to submergence as sea-level rise accelerates. Measuring vertical change on lands protected from human influence allows scientists to understand how vulnerable coastal wetlands are to submergence. But to fully understand this vulnerability, scientists must identify where vertical change in coastal wetlands is being measured across the lower 48 United States, a task that has not yet been undertaken. In this Fact Sheet, we document the spatial distribution of vertical change measurements in coastal wetlands to inform where gaps may still be in the Surface Elevation Table–Marker Horizon (SET-MH) coverage within protected lands across the lower 48 United States.

Released September 20, 2023 12:25 EST

2023, Scientific Investigations Report 2022-5011

Trevor P. Needham, Alex R. Fiore, Scott W. Ator, Jeff P. Raffensperger, Madison B. Smith, Nicole M. Bellmyer, Caitlyn M. Dugan, Carol J. Morel

The soil and groundwater at the Central Chemical facility, Hagerstown, Maryland, are contaminated due to the blending and production of pesticides and fertilizers during much of the 20th century. Remedial investigations focus on two operable units (OU) consisting of the surface soils and waste disposal lagoon (OU-1) and the groundwater (OU-2). The contaminants of concern (COC) for groundwater include 41 compounds categorized within the subgroups of volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), pesticides, and metals. The purpose of this report is to provide a conceptual site model of the hydrogeology and groundwater contaminant transport at and near the Central Chemical facility. The conceptual model was developed through review, synthesis, and interpretation of the results of hydrogeologic, soil, and other environmental investigations conducted at and in the vicinity of the facility in recent decades and is intended to support plans for environmental remediation of the groundwater in OU-2.

The extent and nature of the groundwater contaminant plume associated with the bedrock was characterized for OU-2 of the site. Lithologic and structural comparisons between shallow soil, weathered rock, and epikarst and deeper competent but bedded, dipping, fractured, and karstic limestones illustrate two connected flow systems—a surficial flow system consisting of the unconsolidated overburden and epikarst and a structurally dominant bedrock flow system below the epikarst. Uncertainties exist regarding the nature and transport of contaminants within the epikarst system particularly within voids and perched epikarst water tables. Karst dissolution features are observed within the site including sinkholes and dissolution voids within wells at the site. Of interest, one well in the northern part of the study area (MW-J-71) appears to have a dissolution void connected to an offsite well (OW-2-115) farther to the north. This connection is supported by groundwater level data and elevated concentrations of total suspended solids (TSS) and chlorobenzene in both wells. The high level of TSS supports the possibility of offsite transport of particle-bound contaminants within the conduit system. Episodically elevated concentrations of COC from different groups also were observed within select wells in the epikarst near the waste disposal lagoon (particularly MW-A-51). The variability observed between different COC within the same well may be the result of additional contaminated source materials unrelated to the disposal lagoon. Storage and episodic transport of contaminated material within the epikarst system has the potential to hinder remediation efforts if not considered in the remedial action.

Released September 20, 2023 10:48 EST

2023, Newsletter

Adam J. Sepulveda

No abstract available.

Released September 20, 2023 08:52 EST

2023, Annals of the American Association of Geographers

Aparna Bamzai-Dodson, Amanda E. Cravens, Renee A. McPherson

To help stakeholders such as planners, resource managers, policymakers, and decision makers address environmental challenges in the Anthropocene, scientists are increasingly creating actionable science—science that is useful, usable, and used. Critical physical geography encourages the engagement of stakeholders in the creation of scientific knowledge to conduct actionable science and produce outputs that are directly relevant to stakeholder plans, decisions, or actions. Many scientists, however, lack formal training in how to partner with stakeholders using effective and ethical practices. In this article, we use the core principles for ethical research of respect for persons, beneficence, and justice from the Belmont Report (1979) as a suggested framework to examine the perspectives of stakeholders engaged in climate adaptation science projects. We argue that this framework aligns with the principles of critical physical geography and provides guidance for scientists to make their research more actionable while placing necessary emphasis on ethical considerations. We also challenge scientists to consider the broader ethical implications of engaging with these partners.

Released September 19, 2023 07:48 EST

2023, Scientific Investigations Report 2023-5078

Amy M. Gahala, Jennifer B. Sharpe, Andrew M. Williams

Per- and polyfluoroalkyl substances (PFAS) are a group of synthetic chemicals that have been manufactured and used globally since the 1940s. PFAS are used for their oil- and water-repellent properties, ability to reduce friction, and their flame-retardant nature. PFAS are widely used in a variety of products, including clothing, carpet, food packaging, and firefighting foam. The properties that make them useful in manufacturing, however, also make them persistent and mobile, causing potential exposures to the environment and humans. Known as “forever chemicals,” these compounds resist degradation and have been determined to bioaccumulate in humans and wildlife.

The Illinois Environmental Protection Agency (IEPA) collected a total of 1,711 samples (includes quality-control samples) of finished water at 1,428 entry points from 1,017 Illinois community water supply (CWS) systems and analyzed the water samples for PFAS. The results following confirmation samples indicated a mean of 99 percent of all sample results were below the minimum reporting level (MRL) of 2 nanograms per liter (ng/L). Of the detections at or above the MRL, 7 of 18 PFAS were detected in 149 of 1,428 entry points (about 10 percent). Of the nearly 7.4 million residents directly served by the CWS systems sampled, more than 1.3 million residents (about 18 percent) are served by CWS systems that had at least one detection of PFAS above the MRL of 2 ng/L. The most frequently detected PFAS were perfluorobutanesulfonic acid (about 6.2 percent, 37 ng/L maximum concentration), perfluorooctanesulfonic acid (PFOS) (about 5.0 percent, 150 ng/L maximum concentration), and perfluorooctanoic acid (PFOA) (about 4.8 percent, 25 ng/L maximum concentration). Of the 1,428 entry point samples from the CWS systems, 149 samples had confirmed detections of PFAS, with 93 of those 149 (about 62 percent) samples having at least one PFAS with a concentration that exceeded the median detected concentration of 3.2 ng/L. The highest concentrations detected were 150 ng/L (PFOS) and 140 ng/L (perfluorohexanesulfonic acid) at one CWS location which has been shut down and a different source of water has been provided to the consumers.

Although PFAS detections were more common in CWS systems using surface-water sources (about 35 percent, 30 of 85) and mixed sources (50 percent, 5 of 10) compared to those using groundwater sources (about 9 percent, 114 of 1,333), a greater range of PFAS concentrations were observed in groundwater CWS systems (2 to 150 ng/L) than in surface-water CWS systems (2 to 15 ng/L). Statistically significant differences were determined between some detected PFAS (PFOA, PFOS, and perfluorohexanoic acid) and the source of drinking water (groundwater, surface water, or mixed).

This report summarizes the occurrence and spatial distribution of PFAS in CWS systems across Illinois. The results from this sampling effort could be used by Illinois public health officials to identify the potential risk of PFAS in drinking water to human health.

Released September 19, 2023 07:13 EST

2023, Open-File Report 2023-1024

John M. Besser, Chris D. Ivey, James L. Kunz, Nile E. Kemble, Danielle M. Cleveland, Jeffery A. Steevens, Heidi Dunn, Ryan Foley

The U.S. Geological Survey and collaborators from EcoAnalysts, Inc., completed field and laboratory studies during 2016–19 to evaluate the toxicity of metals to freshwater mussels in streams draining the Tri-State Mining District. This project consisted of (1) sampling and analysis of metals in water and sediment, (2) surveys of mussel assemblages at sites with suitable mussel habitat, (3) toxicity tests with juvenile mussels exposed to zinc or to a mixture of metals (zinc, lead, and cadmium) in water, and (4) toxicity tests to evaluate the contributions of metals in sediment and metals in overlying water to toxic effects on mussels. Field sampling at sites in the Spring River and Neosho River and their tributaries demonstrated wide ranges of metal contamination in water and sediment. Zinc was the predominant toxic metal in water, and concentrations of lead and cadmium were much lower. Mussel areal density and species richness were greater at reference sites with low sediment metal concentrations (for example, zinc, 29–141 micrograms per gram) than at test sites that had higher concentrations of sediment zinc (416–3,420 micrograms per gram) as a result of effects of upstream mining activity. Juvenile mussels were highly sensitive to zinc in water in 12-week toxicity tests compared to previous water-only tests, and adding low levels of waterborne lead and cadmium typical of their occurrence in Tri-State Mining District streams produced greater toxicity. Thresholds for mussel toxicity were at or less than waterborne metal concentrations detected in Tri-State Mining District streams, and sites with waterborne metal concentrations exceeding thresholds had decreased mussel density and decreased mussel species richness. The 12-week toxicity tests with juvenile mussels in Tri-State Mining District sediments also demonstrated negative mussel responses with metal exposure. Thresholds for reductions in survival, growth, or biomass were at sediment metal concentrations less than thresholds reported for previous 4-week tests. We documented strong associations between reduced survival in laboratory tests and reduced species richness in community surveys. Attempts to estimate combined toxicity thresholds for metals in sediment and overlying water were not successful. These inconclusive results may be attributable to several factors, including (1) unexpected losses of waterborne metals from solution, (2) differences in sensitivity of different age/size classes of juvenile mussels, (3) disruption of sediment-water equilibria and changes in metal bioavailability, and (4) behavioral or physiological responses allowing juvenile mussels to temporarily reduce or avoid metal exposure. We also observed differences in metal toxicity thresholds between sediment toxicity tests started with different ages/sizes of test organisms. A followup study that combined exposure to Tri-State Mining District sediments with exposures to multiple levels of waterborne metals demonstrated toxic effects of sediments with low metal concentrations; however, some treatments also indicated unexpected reversals of concentration-response trends and reduced toxicity in treatments that had high metal concentrations in overlying water. These unusual responses may reflect development of physiological tolerance to metal toxicity by induction of metal-binding proteins (for example, metallothionein) in response to high metal levels in water.

Results of laboratory and field studies indicated strong associations between metal exposure in Tri-State Mining District streams and toxic effects on juvenile freshwater mussels. Mussel community characteristics corresponded to differences in metal concentrations in sediment and water among Tri-State Mining District sampling sites. Responses of juvenile mussels in 12-week water and sediment exposures were strongly correlated with the status of mussel assemblages in Tri-State Mining District streams. The combined results support the hypothesis that exposure to metals from historical mining activities adversely affects freshwater mussel communities in the Spring River/Neosho River drainage.

Released September 18, 2023 14:16 EST

2023, General Information Product 220

Carolyn L. Driedger, Alysa Adams, Michael A. Clynne, Kristi Cochrane, Abi Groskopf, Emma Johnson, Heather Monti, Elizabeth Westby

This poster provides an overview of Mount St. Helens’ eruption history and emphasizes the continuous transformation of the volcanic landscape and its ecosystems. After each eruption, the landscape and ecosystems are not so much restored as they are morphed into new forms and patterns.

Released September 18, 2023 12:19 EST

2023, Scientific Investigations Report 2023-5098

Cassandra D. Smith, Tamara M. Wood

Malheur Lake is the largest lake in the endorheic Harney Basin in southeastern Oregon. Since the 1990s, Malheur Lake—which averages depths of about 1 meter—has been in a degraded, turbid state lacking submergent and emergent vegetation. The goals of this study were to identify the major sources of sediment and nutrients to Malheur Lake to determine the importance of managing nutrients for lake restoration. Discrete water samples were analyzed for nutrient (total phosphorus, total nitrogen, orthophosphate, nitrate+nitrite, and ammonia) and suspended-sediment concentrations, and additional parameters including chlorophyll-a and phytoplankton biomass were measured in lake samples. Lake area fluctuated from a minimum of 3,300 hectares (ha) to a maximum of 11,300 ha in water years 2019 and 2020. In water year 2019, inflow from the tributaries created a 1,400-hectare area in the lake with low turbidity that persisted for multiple months. Land-use practices and water diversions along the tributaries affected the hydrographs and nutrient and suspended-sediment concentrations reaching the lake. As lake area increased, storage of sediment-associated constituents in the water column increased in excess of external loads because of resuspension. In 2019, 69 percent of the increase in suspended-sediment storage in the water column was attributed to internal resuspension and 31 percent was from external loading. Sediment was deposited as lake area decreased, and water-column storage decreased even as positive external loading continued. The internal resuspension, deposition, and external loading of suspended sediment likely is decreasing topographic heterogeneity in the lake. Concentrations of total phosphorus and orthophosphate are substantially higher than in the 1980s, and the lake is eutrophic. Phytoplankton in the lake was light limited in 2019–20, and restoration actions that prioritize vegetation establishment would reduce bioavailable nutrients for phytoplankton while increasing light in the water column.

Released September 18, 2023 10:07 EST

2023, Scientific Investigations Report 2023-5058

Meghan T. Bell, Anne C. Tillery

The Federal Clean Water Act stipulates that States adopt water-quality standards to protect and enhance the quality of water in those States and to protect water quality through the creation of planning documents and discharge permits. Critical low-flow values, including the 4-day, 3-year low-flow frequency (4Q3) and harmonic mean streamflows, are necessary for developing those planning documents and permits. The U.S. Geological Survey computed the 4Q3 and adjusted harmonic mean streamflows using data from 96 streamgages on perennial streams, and regression equations were developed for the estimation of these parameters at ungaged, perennial streams in the State of New Mexico using weighted least-squares regression and readily accessed basin and climatic characteristics. Six equations were developed for the 4Q3 statistic, and five equations were developed for the adjusted harmonic mean statistic. Separate equations were developed for sites located in basins with mean elevations equal to or greater than 8,000 feet above the National Geodetic Vertical Datum of 1929 (except where noted as the North American Vertical Datum of 1988), as well as for sites on streams that are tributary to the San Juan River. Pseudo R-squared values ranged from 0.53 to 0.87 (4Q3) and adjusted R-squared values ranged from 0.69 to 0.89 (adjusted harmonic mean). For sites in basins with mean elevations of less than 8,000 feet above the National Geodetic Vertical Datum of 1929 (except where noted as the North American Vertical Datum of 1988), equations were developed based on contributing drainage area size. Drainage area, mean basin elevation, basinwide mean annual precipitation, and mean basin slope were found to have relations to the 4Q3; drainage area, mean basin elevation, basinwide mean annual precipitation, mean basin slope, and mean basinwide precipitation for the winter period, defined as the months of October through April, were found to have relations to the adjusted harmonic mean. Comparison to previous 4Q3 regression equations using fit statistics indicate an overall improvement in performance.

Released September 18, 2023 09:02 EST

2023, Data Report 1181

Gabriel B. Senay, David A. Helweg, Stefanie Kagone, John B. Taylor, Thomas Cecere, Tiare Eastmond, Amy Koch, Kurtis Nelson, Lajikit Rufus

The Republic of the Marshall Islands (also known as the Marshall Islands) is a nation of more than 30 low-lying atolls and islands, most of which are inhabited, dispersed across an Exclusive Economic Zone over 770,000 square miles in the tropical central north Pacific Ocean. Monitoring environmental conditions for potential drought risk is challenging in such a dispersed island nation, and current drought hazard products provide generalities regarding conditions on a broad geographic scale. U.S. Geological Survey scientists and managers of natural resources and natural hazards in the Marshall Islands used Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (called “IMERG”) satellite estimates of precipitation to develop content and a template for timely monthly reporting of precipitation for 23 inhabited atolls and islands. The IMERG data are available in a U.S. Geological Survey data release at https://doi.org/10.5066/P95ANG3N. The monthly reports itself are available in a U.S. Geological Survey data release at https://doi.org/10.5066/P90J1426. This Data Report describes the collaboration process and results of developing the report content and layout.

Released September 18, 2023 06:59 EST

2023, Biological Conservation (286)

Kylee Denise Dunham, Patrick K. Devers, Abigail Jean Lawson, James E. Lyons, Conor P. McGowan, Andy Royle

Released September 18, 2023 06:56 EST

2023, Geological Society of London Monograph, Arctic Sedimentary Basins (57)

Deborah Hutchinson, David W. Houseknecht, David Mosher

Released September 18, 2023 06:43 EST

2023, Geochimica et Cosmochimica Acta (360) 57-67

Xiaoqiang Li, Hao Xie, Justin E. Birdwell, Gregory McGovern, Juske Horita

Released September 15, 2023 13:20 EST

2023, Scientific Investigations Report 2023-5091

Mitchell A. McAdoo, Gregory T. Connock, Mark D. Kozar

Abandoned underground coal mine aquifers cover a large part of West Virginia and could supply substantial quantities of water for agricultural, industrial, residential, and public use. Several Federal, State, and academic institutions have studied the availability and quality of water stored in abandoned underground coal mine aquifers for a variety of applications, such as economic development, geothermal energy, aquaculture, and wastewater disposal. However, the spatial and stratigraphic controls on water quality produced from abandoned underground coal mine aquifers are still poorly constrained on a state-wide basis. In response to these knowledge gaps, the U.S. Geological Survey initiated a study, in cooperation with the West Virginia Department of Environmental Protection, to understand the applicability of using existing secondary source data for understanding water quality in abandoned underground coal mine aquifers across the State.

Results from the calculation of net alkalinity indicated that Upper Pennsylvanian coal beds primarily produce net acidic waters and Lower Pennsylvanian coal beds primarily produce net alkaline waters. Multivariate statistical analysis of elemental data supports the conclusion that abandoned underground coal mine aquifers in the northern part of the State generally produce poor water quality and abandoned underground coal mine aquifers in southern West Virginia primarily produce good water quality. These results substantiate the potential benefits of leveraging abandoned underground coal mine aquifers as a multifaceted resource in West Virginia and can be used as a reconnaissance tool for water managers to characterize abandoned underground coal mine aquifers on a local scale.

Released September 15, 2023 10:13 EST

2023, Stratigraphy (20) 225-231

Harry J. Dowsett, Marci M. Robinson, Kevin M. Foley, Steve Hunter, Aisling M Dolan, Julia C. Tindall

Global reconstructions of Pliocene climate provide important insights into how the climate system operates under elevated temperatures and atmospheric CO2 levels. These reconstructions have been used extensively in paleoclimate modeling experiments for comparison to simulated conditions, and as boundary conditions.Most previous work focused on the Late Pliocene interval known as the mid Piacenzian Warm Period (mPWP), the interval originally identified by the U.S. Geological Survey Pliocene Research, Interpretation and Synoptic Mapping Project (PRISM) as the PRISM interval or Mid Pliocene Warm Period. The term Mid Pliocene Warm Period is a misnomer due to changes to the geological time scale, and its use should be discontinued. The Pliocene Model Intercomparison Project (PlioMIP), now in its third phase, is expanding to include a focus on the Early Pliocene (Zanclean). PlioMIP3 experiments will allow comparison of environmental and climatic conditions before and after closure of the Central American Seaway (CAS). PlioMIP3 used the annual insolation pattern at the top of the atmosphere to determine time slices in the Zanclean that have orbital configurations that are most similar to modern. Two have been selected by PlioMIP and adopted by PRISM for inclusion in future studies: PRISM5.1 (4.474 Ma) and PRISM5.2 (4.870 Ma). Here we establish the stratigraphic framework for these Early Pliocene time slices and furnish information to help locate these intervals in proxy records of paleoenvironmental data using oxygen isotope stratigraphy, paleomagnetic stratigraphy, biostratigraphy, and biochronology (calibrated planktic foraminifer and calcareous nannofossil events).

Released September 15, 2023 09:40 EST

2023, Book chapter, Wildlife disease and health in conservation

Andrew M. Ramey

Influenza A viruses (IAVs)maintained among wild waterfowl, gulls, shorebirds, and some seabirds, and typically do not cause disease. Some avian-origin IAVs that have previously spilled over into domestic poultry have developed a highly pathogenic phenotype and have become important pathogens affecting both wild birds and poultry. These avian-origin IAVs have important implications to the production and trade of domestic birds, conservation and management of wild birds, and the risk of spillover of zoonotic influenza to humans handling infected birds.

Released September 15, 2023 09:38 EST

2023, Ibis

Daniel R. Ruthrauff, Christopher M. Harwood, T. Lee Tibbitts, Vijay P. Patil

Survival estimates are critical components of avian ecology. In well-intentioned efforts to maximize the utility of one's research, survival estimates often derive from data that were not originally collected for survival assessments, and such post hoc analyses may include unintentional biases. We estimated the survival of Whimbrels captured and marked at two breeding sites in Alaska using divergent data streams that in isolation were subject to methodological biases. Although both capture sites were chosen to study the migration ecology of Alaska-breeding Whimbrels, maximizing the conservation value of the data we collected was obviously desirable. We used multi-year telemetry information to infer survival from one site (Colville River) and mark-resight techniques to estimate survival from a second site (Kanuti River). At the Colville River, we could not feasibly include a control group of birds to assess potential survival effects of externally mounted transmitters, while at Kanuti River we were unable to accurately account for potential emigration events because we used resightings alone. We integrated these datasets in a Bayesian hierarchical framework, an approach that permitted insights across sites that moderated methodological biases within sites. Using telemetry enabled us to detect permanent emigration events from breeding sites in two of ten birds; results that informed estimates for birds without tracking devices. These datasets yielded point estimates of true survival of Whimbrels from Colville River equipped with solar-powered satellite transmitters that were higher (0.83) than true survival estimates of Whimbrels from Kanuti River marked with leg flags alone (0.74) or equipped with surgically implanted satellite transmitters (0.50), but the 95% credible intervals on these estimates overlapped across groups. For species like Whimbrels that are difficult and costly to study, combining information from disparate data streams allowed us to derive novel demographic estimates, an approach with clear application to other similar studies.

Released September 15, 2023 09:18 EST

2023, Marine Ecology Progress Series

Brian H. Robinson, Heather A. Coletti, Brenda Ballachey, James L. Bodkin, Kimberly A. Kloecker, Sarah Beth Traiger, Daniel Esler

The Pacific marine heatwave (PMH) of 2014-2016 was an intense, long-lasting environmental disturbance expressed throughout the north Pacific. While dramatic consequences of the PMH on pelagic food webs have been well documented, effects on nearshore food webs, i.e., those based on macroalgae primary productivity, benthic invertebrate intermediate consumers, and specialized benthivorous top predators including some marine birds, are not well understood. We conducted summer and winter coastline surveys in two National Parks in the northern Gulf of Alaska from 2006 – 2022. We evaluated changes in abundance of benthivorous marine birds in relation to the heatwave, after accounting for effects of season and region. We also evaluated changes in abundance of nearshore benthic invertebrate prey data to allow specific consideration of a prey-based mechanism for effects of the PMH across food webs. We found that benthivorous marine birds, consisting largely of sea ducks and shorebirds, did not show a strong response to the PMH, unlike significant effects demonstrated by piscivorous birds in pelagic biomes. Unlike extreme reductions in quantity and quality of forage fish documented in other studies, we found that common benthic invertebrate prey abundance remained relatively stable, with only minor increases or decreases, in association with the PMH. Our results support the hypothesis that food availability has a strong mediating effect of the PMH on upper trophic levels across food webs. These findings show how a large-scale environmental perturbation affects biological communities through trophic pathways, provides insight into ecosystem resiliency, and can inform management strategies in the face of persistent climate change.

Released September 15, 2023 09:17 EST

2023, Book chapter, Wildlife disease and health in conservation

Carter T. Atkinson

No abstract available.

Released September 15, 2023 09:09 EST

2023, Earth's Future (11)

Sanne Muis, Jeroen C. J. H. Aerts, José A. Á. Antolínez, Job C. Dullaart, Trang Minh Duong, Li H. Erikson, Rein J. Haarsma, Maialen Irazoqui Apecechea, Matthias Mengel, Dewi Le Bars, Andrea C. O'Neill, Roshanka Ranasinghe, Malcolm J. Roberts, Martin Verlaan, Philip J. Ward, Kun Yan

In the coming decades, coastal flooding will become more frequent due to sea-level rise and potential changes in storms. To produce global storm surge projections from 1950 to 2050, we force the Global Tide and Surge Model with a ∼25-km resolution climate model ensemble from the Coupled Model Intercomparison Project Phase 6 High Resolution Model Intercomparison Project (HighResMIP). This is the first time that such a high-resolution ensemble is used to assess changes in future storm surges across the globe. We validate the present epoch (1985–2014) against the ERA5 climate reanalysis, which shows a good overall agreement. However, there is a clear spatial bias with generally a positive bias in coastal areas along semi-enclosed seas and negative bias in equatorial regions. Comparing the future epoch (2021–2050) against the historical epoch (1951–1980), we project ensemble-median changes up to 0.1 (or 20%) in the 1 in 10-year storm surge levels. These changes are not uniform across the globe with decreases along the coast of Mediterranean and northern Africa and southern Australia and increases along the south coast of Australia and Alaska. There are also increases along (parts) of the coasts of northern Caribbean, eastern Africa, China and the Korean peninsula, but with less agreement among the HighResMIP ensemble. Information resulting from this study can be used to inform broad-scale assessment of coastal impacts under future climate change.

Released September 15, 2023 09:01 EST

2023, Canadian Journal of Fisheries and Aquatic Sciences

David James Páez, Jacob L. Gregg, Ashley MacKenzie, Sophie Amanda Hall, Paul Hershberger

We characterized a natural sea louse epizootic of Caligus clemensi and the effects of parasitism on Pacific herring Clupea pallasii in Port Angeles Harbor, WA, USA. Infestation prevalence on newly metamorphosed age 0 Pacific herring reached 100% prevalence by mid-August. At this time, the mean louse intensity was 4.6 lice/fish, and a positive correlation occurred between louse intensity and herring body length. The epizootic then waned, with infestation prevalence decreasing to less than 25% and the mean parasite intensity falling below 1 louse. While skin injuries were not detected, motile lice preferentially aggregated around head and anterior dorsal areas. However, louse tropism became evenly distributed over the body as the parasite intensity increased. Louse-induced mortality in herring was negligible in controlled experiments. These results indicate that Caligus clemensi epizootics reach high prevalence, but also fade from mid-summer to early fall. Due to the predominant presence of motile copepod stages, we suggest that the epizootic fades because lice complete their life cycle and dislodge from the host; however, multiple explanations for epidemic fading are possible.

Released September 15, 2023 08:56 EST

2023, Journal of Ecology

Thomas A. Bytnerowicz, Jennifer L. Funk, Duncan N. L. Menge, Steven Perakis, Amelia A. Wolf

1. Nitrogen (N)-fixing trees are thought to break a basic rule of leaf economics: higher leaf N concentrations do not translate into higher rates of carbon assimilation. Understanding how leaf N affects photosynthesis and water use efficiency (WUE) in this ecologically important group is critical.
2. We grew six N-fixing and four non-fixing tree species for 4–5 years at four fertilization treatments in field experiments in temperate and tropical regions to assess how functional type (N fixer vs. non-fixer) and N limitation affected leaf N and how leaf N affected light-saturated photosynthesis (A_sat), stomatal conductance (g_sw) and WUE (WUE_i and δ¹³C).
3. A_sat, WUE_i and δ¹³C, but not g_sw, increased with higher leaf N. Surprisingly, N-fixing and non-fixing trees displayed similar scaling between leaf N and these physiological variables, and this finding was supported by reanalysis of a global dataset. N fixers generally had higher leaf N than non-fixers, even when non-fixers were not N-limited at the leaf level. Leaf-level N limitation did not alter the relationship of A_sat, g_sw, WUE_i and δ¹³C with leaf N, although it did affect the photosynthetic N use efficiency. Higher WUE was associated with higher productivity, whereas higher A_sat was not.
4. Synthesis: The ecological success of N-fixing trees depends on the effect of leaf N on carbon gain and water loss. Using a field fertilization experiment and reanalysis of a global dataset, we show that high leaf-level photosynthesis and WUE in N fixers stems from their higher average leaf N, rather than a difference between N fixers and non-fixers in the scaling of photosynthesis and WUE with leaf N. By clarifying the mechanism by which N fixers achieve and benefit from high WUE, our results further the understanding of global N fixer distributions.

Released September 15, 2023 08:44 EST

2023, Geophysical Research Letters (50)

MaryLynn Musgrove, Bryant Jurgens, Stephen P. Opsahl

Karst aquifers are a vital groundwater resource globally, but features such as rapid recharge and conduit flow make them highly vulnerable to land-surface contamination. We apply environmental age tracers to the south-central Texas Edwards aquifer, a karst resource in a rapidly urbanizing and drought-prone region, to assess vulnerability to land-surface contamination and risks unique to karst aquifers. We show that vulnerability of Edwards aquifer groundwater follows similar spatial and depth patterns common to porous-media type aquifers, despite complicated karst hydrogeologic features. Shallow and unconfined parts are more vulnerable to land-surface contamination than the deeper and confined parts, although even the oldest groundwater is mixed with some recent recharge. When modeled age-tracer results are coupled with other independent geochemical tracers of water-rock interaction specific to karst settings, they can yield insight into residence time and associated vulnerability.

Released September 15, 2023 08:43 EST

2023, Book chapter, Wildlife disease and health in conservation

Thierry M. Work

David A. Jessup, Robin W. Radcliffe, editor(s)

No abstract available.

Released September 15, 2023 08:11 EST

2023, Bulletin of the American Meteorological Society (104) E1587-E1605

Nina S. Oakley, Tao Liu, Luke McGuire, Matthew Simpson, Benjamin J. Hatchett, Alexander Tardy, Jason W. Kean, Christopher Castellano, Jayme L. Laber, Daniel Steinhoff

Post-wildfire debris flows (PFDF) threaten life and property in western North America. They are triggered by short-duration, high-intensity rainfall. Following a wildfire, rainfall thresholds are developed that, if exceeded, indicate high likelihood of a PFDF. Existing weather forecast products allow forecasters to identify favorable atmospheric conditions for rainfall intensities that may exceed established thresholds at lead times needed for decision-making (e.g., ≥24 h). However, at these lead times, considerable uncertainty exists regarding rainfall intensity and whether the high-intensity rainfall will intersect the burn area. The approach of messaging on potential hazards given favorable conditions is generally effective in avoiding unanticipated PFDF impacts, but may lead to “messaging fatigue” if favorable triggering conditions are forecast numerous times, yet no PFDF occurs (i.e., false alarm). Forecasters and emergency managers need additional tools that increase their confidence regarding occurrence of short-duration, high-intensity rainfall as well as tools that tie rainfall forecasts to potential PFDF outcomes. We present a concept for probabilistic tools that evaluate PFDF hazards by coupling a high-resolution (1-km), large (100-member) ensemble 24-h precipitation forecast at 5-min resolution with PFDF likelihood and volume models. The observed 15-min maximum rainfall intensities are captured within the ensemble spread, though in highest ∼10% of members. We visualize the model output in several ways to demonstrate most likely and most extreme outcomes and to characterize uncertainty. Our experiment highlights the benefits and limitations of this approach, and provides an initial step toward further developing situational awareness and impact-based decision-support tools for forecasting PFDF hazards.

Released September 15, 2023 07:46 EST

2023, Wildlife Society Bulletin (47)

Richard J. Camp, Chauncey K. Asing, Paul C. Banko, Lainie Berry, Kevin W. Brinck, Chris Farmer, Ayesha Genz

Effective species management and conservation benefit from knowledge of species distribution and status. Surveys to obtain that information often involve replicate sampling, which increases survey effort and costs. We simultaneously modeled species distribution, abundance and spatial correlation, and compared the uncertainty in replicate abundance estimates of the endangered palila (Loxioides bailleui) using hierarchical generalized additive models with a soap film smoother that incorporated random effects for visit. Based on survey coverage and detections, we selected the 2017 point-transect distance sampling survey on Mauna Kea, Hawai‘i Island, for our modeling. Our modeling approach allowed us to account for imperfect detections, control the effects of boundary features, and generate visit-specific density surface maps. We found that visit-specific smooths were nearly identical, indicating that little information was gained from a subsequent visit, and that most of the estimator uncertainty was derived from within-visit variability. Scaling back the palila survey to a single visit would halve the survey effort and logistical costs and increase efficiencies in data management and processing. Changing the sampling protocol warrants careful consideration and our findings may help management and regulatory agencies by maximizing efficiency and minimizing costs of surveying protocols, while providing guidelines on how to best collect information critical to species' conservation.

Released September 15, 2023 07:17 EST

2023, Journal of Hydraulic Engineering (149)

Jennifer G Duan, Frank Engel, Ammon F Cadogan

Released September 15, 2023 07:03 EST

2023, Ecological Indicators (155)

Cara Applestein, Matthew Germino

Understanding the accuracy and appropriate application scale of satellite-derived maps of vegetation cover is essential for effective management of the vast, remote rangelands of the world. However, the underlying models are updated frequently and may combine with rapidly changing vegetation conditions to cause variations in accuracy and precision over time. We sought to assess how model performance changed between different versions of satellite-derived cover products (Rangeland Analysis Platform, RAP, and Rangeland Condition Monitoring and Assessment Protocol, RCMAP) and how the performance of LandCart compared to RAP and RCMAP. Additionally, we asked how variability in agreement between LandCart and field-based models varied with scale. We utilized an intensive dataset of grid-point intercept functional group cover data collected between 2016 and 2020 across the ∼113 kHA 2015 Soda Wildfire to 1) evaluate r² agreement between versions of each satellite-derived product and plot-level field data and 2) assess relative standard error of agreement in cover between LandCart and continuous field-based Empirical Bayesian Kriging (EBK) regression models. Agreement between satellite- compared to field-plot values of cover (r²) increased for RCMAP Version 5.0 compared to Version 2.0, but there were negligible changes between versions of RAP. Despite this, r² values of RCMAP and LandCart were nearly always less than RAP. Variability in agreement between EBK regression model cover and LandCart-derived cover decreased with the scale of consideration. Variability in agreement between satellite-derived cover products and field-based metrics is lowest at larger scale (mega-fire or regional) and varies from year to year and across versions, which could complicate detection of temporal changes in plant cover.

Released September 15, 2023 07:03 EST

2023, Fisheries Management and Ecology

Andrew Edgar Honsey, Yu-Chun Kao, Christopher Olds, David Bunnell

Released September 14, 2023 10:14 EST

2023, Scientific Investigations Report 2010-5090-CC

Mark D. Cocker, Greta J. Orris, Pamela Dunlap, Chao Yang, James D. Bliss

The U.S. Geological Survey (USGS) assessed undiscovered potash resources in the Elk Point Basin in Canada and the United States as part of a global mineral resource assessment. The Elk Point Basin is a large, Middle Devonian (Givetian) intracratonic evaporite basin covering approximately 1,200,000 square kilometers (km²) and filled mainly with marine evaporite and minor clastic sedimentary rocks that contain stratabound potash-bearing salt. The potash-bearing salt is concentrated in four stratigraphic members (Patience Lake, Belle Plaine, White Bear, and Esterhazy) in the upper 100 meters (m) of the Prairie Evaporite and are separated by beds of halite (NaCl) that contain lesser—presently non-economic—amounts of sylvite (KCl) and carnallite (KMgCl₃·6H₂O). The principal ore-bearing salt contains mainly sylvite. Four permissive tracts were defined that permit the presence of undiscovered stratabound potash (both sylvite- and carnallite-bearing salt) using geological criteria.

Permissive tracts are defined by the spatial extent of each stratigraphic member that is at least 1 m thick, are less than 3 kilometers (km) from the surface, contain at least 4 percent equivalent potassium oxide (K₂O), and contain the currently known resources. The permissive tracts include known potash deposits and potash occurrences as wells or mines not in production and show where undiscovered potash resources may be present. Well data are used to define the extent, thickness, average K₂O equivalent grades, and volumes of each member. Data were supplied by the Saskatchewan Geological Survey or were obtained from published National Instrument (NI) 43-101 technical reports and other published reports, such as annual 10-K reports or news releases.

The Elk Point Basin is the world’s largest source of potash, producing 23.0 million metric tons (Mt) of potassium chloride (KCl) (the equivalent of about 14.4 Mt of K₂O) in 2018. In terms of global importance, the Elk Point Basin may contain 40 to greater than 50 percent of the world’s potash resources. Since 1962, potash companies have mined more than 1.5 trillion metric tons of ore containing 605 Mt of KCl (the equivalent of about 380 Mt of K₂O). The total value of the ore produced through 2018 is on the order of $70 trillion (CAD). Potash is currently produced from eight conventional and three underground solution mines at depths ranging from 900 m to nearly 1,800 m. Estimates of the amount of potash in the Elk Point Basin vary considerably and the data and methods used in those estimations are not well documented. Known potash resources are approximately 99 billion metric tons (Bt) of ore containing 22 Bt of K₂O equivalent.

As a result of new mine openings and increased production capacity at existing mines, the total production capacity of mines in the Elk Point Basin has increased significantly (to about 32.8 Mt of KCl or 22.8 Mt of K₂O equivalent per year). Additional production capacity of about 31 Mt of KCl (or 17 Mt of K₂O equivalent) per year could be realized over the next decade if several current (as of 2019) exploration and development projects reach production status.

Stratabound potash-bearing salt of the Prairie Evaporite presently underlies a total area of about 188,000 km² and has a total volume of about 2,690 cubic kilometers (km³). Post-depositional solution processes considerably modified the mineralogy and presence of the potash-bearing salt. These changes had a profound effect on the volume and grade of potash resources that remained in the Prairie Evaporite and are a major consideration of exploration and mining operations as well as in this assessment of undiscovered potash resources.

This USGS assessment includes the locations and possible amounts of undiscovered potash resources in the Prairie Evaporite. Volumes for each stratigraphic member were computed using member thicknesses and areal extent modified by actual, estimated geologic loss owing to salt dissolution and extraction ratios, as well as estimated distribution of carnallite and sylvite. Both sylvite- and carnallite-bearing salts were assessed for potash in this study. The assessment uses modern published grade and tonnage data. The amount of undiscovered potash is estimated by using Monte Carlo simulations to combine volume estimates of the potash-bearing members with probability distributions for average grade and bulk density.

Mean potash grades (expressed as percentage of K₂O equivalent) calculated using drill core analyses are 17.76 for the Patience Lake Member, 15.98 for the Belle Plaine Member, 10.66 for the White Bear Member, and 15.30 for the Esterhazy Member. Geologic losses reported as extraction ratios during mining may range from 27.5 to 41.6 percent and are dependent on mining method and local geologic conditions. The assessment determined that mean estimated undiscovered K₂O equivalent resources for the Patience Lake, Belle Plaine, White Bear, and Esterhazy Members are 340, 220, 34, and 190 Bt, respectively, and estimated a total mean of 790 Bt for the entire Prairie Evaporite above a depth of 3 km. The total mineralized rock tonnage is estimated to be about 5,000 Bt. Most of the assessed potash is located within Saskatchewan with lesser amounts in Alberta and Manitoba as well as Montana and North Dakota within the United States.

Although carnallite is mined for potash in Europe, it has historically been avoided in mining plans for potash-producing companies in Saskatchewan because of mining, processing, and grade considerations. Carnallite-rich salt is locally present in concentrations and volumes that could be a significant resource of magnesium chloride (MgCl₂) obtained as a byproduct of processing the carnallite for potash. Previously estimated reserves (not NI 43-101 compliant) of mineralized material from 1955 to 2019 are 695 Mt at 22.1 percent MgCl₂. The total amount of K₂O equivalent as carnallite was estimated during this USGS assessment to be about 120 Bt (or 180 Bt KCl). With uncertainties in defining the areal extent of carnallite in each of the potash-bearing members, the amount of MgCl₂ as carnallite in the Elk Point Basin could be approximately 180 Bt.

Released September 14, 2023 09:42 EST

2023, Book chapter, Climate Change and Estuaries

Daniel A. Friess, Luzhen Chen, Nicole Cormier, Ken Krauss, Catherine E. Lovelock, Jacqueline L. Raw, Kerrylee Rogers, Neil Saintilan, Frida Sidik

Michael J. Kennish, Hans W. Paerl, Joseph Crosswell, editor(s)

The position of mangrove forests in the dynamic intertidal zone means that they are expected to be heavily impacted by climate change. Much focus is put on mangroves and their response to sea-level rise, but this ecosystem is exposed to a much broader range of climate change stressors, including increased storminess and waves, more dynamic and unpredictable precipitation patterns, and increases in air and sea surface temperatures, particularly at their latitudinal limits. We show that individual climate change stressors can have (rarely considered) positive, as well as negative impacts on mangroves and associated ecosystem functions such as carbon sequestration. While we generally study climate change stressors individually, they are not expected to act in isolation with other climate change stressors or with anthropogenic stressors. We present a stressor interaction framework previously suggested for coral reefs, and adapt it for use in mangroves, using the recent mangrove dieback in northern Australia as a case study. We show the benefits of moving mangrove and climate change research beyond the study of single stressors and towards identifying key synergistic and antagonistic interactions between climate change stressors.

Released September 14, 2023 09:19 EST

2023, Ecosphere (14)

Brian Patrick Folt, Kathryn A. Schoenecker, L. Stefan Ekernas, David R. Edmunds, Mark T. Hannon

Feral horse (Equus caballus) population management is a challenging problem around the world because populations often exhibit density-independent growth, can exert negative ecological effects on ecosystems, and require great cost to be managed. However, strong value-based connections between people and horses cause contention around management decisions. To help make informed decisions, natural resource managers might benefit from more detailed understanding of how horse management alternatives, including combinations of removals and fertility control methods, could achieve objectives of sustainable, multiple-use ecosystems while minimizing overall horse handling and fiscal costs. Here, we describe a modeling tool that simulates horse management alternatives and estimates trade-offs in predicted metrics related to population size, animal handling, and direct costs of management. The model considers six management actions for populations (removals for adoption or long-term holding; fertility control treatment with three vaccines, intrauterine devices, and mare sterilization), used alone or in combination. We simulated 19 alternative management scenarios at 2-, 3-, and 4-year management return intervals and identified efficiency frontiers among alternatives for trade-offs between predicted population size and six management metrics. Our analysis identified multiple alternatives that could maintain populations within target population size ranges, but some alternatives (e.g., removal and mare sterilization, removal and GonaCon treatment) performed better at minimizing overall animal handling requirements and management costs. Cost savings increased under alternatives with more effective, longer lasting fertility control techniques over longer management intervals compared with alternatives with less-effective, shorter lasting fertility control techniques. We built a user-friendly website application, PopEquus, that decision makers and interested individuals can use to simulate management alternatives and evaluate trade-offs among management and cost metrics. Our results and website application provide quantitative trade-off tools for horse population management decisions and can help support value-based management decisions for wild or feral horse populations and ecosystems at local and regional scales around the world.

Released September 14, 2023 08:39 EST

2023, Book chapter, Climate change and estuaries

Lisamarie Windham-Myers

Michael J. Kennish, Hans W. Paerl, Joseph Crosswell, editor(s)

Blue carbon, a convenient term to encompass the climate mitigation value of coastal carbon dynamics, has received global policy attention and growing datasets to support management actions. Carbon stock assessments in mangroves, seagrass, and tidal marshes document significant carbon storage in soils. Models illustrate significant downward fluxes of carbon dioxide and limited methane emissions, making tidal wetland preservation and restoration notably potent for carbon dioxide removal (CDR). Natural variation in different carbon stocks and fluxes has led to prioritization efforts to characterize coastal lands across physical and biological gradients. However, a larger concern beyond upscaling carbon dynamics is the resilience of these stocks and fluxes with global changes. Data-informed models have greatly improved our assessments of the vulnerability of soil and biomass stocks, greenhouse gas (GHG) balance, and spatial extents. Accelerated sea-level rise is increasingly concerning, but its impacts vary by resilience context, as very few coastal lands are without direct human impact. As the landscape context has changed, blue carbon fluxes have also shifted in terms of importance and distribution. New incentives for tidal ecosystem management are expanding boundaries to include algal carbon and tidal transport of alkalinity, which bring additional co-benefits to coastal waters. Using examples from the conterminous USA on blue carbon stocks, radiative balance, and extent, this chapter explores timelines of physical and biogeochemical stressors and their application to past, current, and future climate mitigation functions of coastal ecosystems.

Released September 14, 2023 07:09 EST

2023, Endangered Species Research (52) 1-15

Nathan Johnson, Caitlin Beaver, Alexander H. Kiser, Matthew A. Duplessis, Matthew D. Wagner, Robert J. Ellwanger, Clinton R. Robertson, Sean D. Kinney, Beau B. Gregory, Steve Wolverton, Charles R. Randklev, Paul D. Hartfield, James D. Williams, Chase H. Smith

Accurate taxonomic and distributional information are arguably the most critical components of conservation status assessments but can be greatly affected by misidentifications. The Louisiana pigtoe Pleurobema riddellii is a freshwater mussel proposed as threatened under the US Endangered Species Act. The species belongs to the tribe Pleurobemini, which includes multiple taxa that are inherently challenging to identify without molecular data. We validated historical and recent survey records of P. riddellii using a combination of DNA sequence data and morphological characters to provide a more definitive assessment of range and spatiotemporal trends in distribution. Our comprehensive assessment identified specimens collected from the Pearl drainage as P. riddellii, extending the species’ known range into eastern Gulf of Mexico drainages. Contemporary records were unavailable from the Trinity drainage; however, we designed novel minibarcode PCR primers and used historical DNA from a specimen collected in the late 1800s to confirm the historical presence of P. riddellii at the species’ type locality in the Trinity River near Dallas, Texas, USA. Our range-wide genetic diversity assessment provides strong support for 2 main geographic groups, the Ouachita and all remaining populations, with individuals from the Pearl and Trinity drainages sharing haplotypes with conspecifics from other drainages. Available data suggest P. riddellii has been extirpated from a significant portion of the historical range, including the entire Trinity drainage. Additional surveys in Lake Pontchartrain, Trinity, and other drainages in the eastern periphery of the species’ range may provide additional clarity on the distribution and conservation status of P. riddellii.

Released September 14, 2023 06:55 EST

2023, Ecohydrology

Beth Middleton

Released September 14, 2023 06:49 EST

2024, Journal of Hazardous Materials (461)

Rongrong Xuan, Xiaojian Qiu, Jiazhen Wang, Shai Liu, Jason Tyler Magnuson, Bentuo Xu, Wenhui Qui, Chunmiao Zheng

Released September 13, 2023 14:41 EST

2023, Conference Paper, Proceedings of SGA 2023: Mineral resources in a changing world

Jeffrey L. Mauk, Jonathan Andrew Funk, Nick Karl

No abstract available.

Released September 13, 2023 13:51 EST

2023, Geomorphology (438)

Eli Schwat, Erkan Istanbulluoglu, Alex Horner-Devine, Scott W. Anderson, Friedrich Knuth, David Shean

Understanding land surface change in and sediment export out of proglacial landscapes is critical for understanding geohazard and flood risks over engineering timescales and characterizing landscape evolution over geomorphic timescales. We used automated Structure from Motion software to process historical aerial photographs and, with modern lidar data, generated a high-resolution DEM time series with coverage over 10 glacierized watersheds on Mount Baker, Washington, USA for the time period between 1947 and 2015. We measured basin-wide sediment yields and sediment redistribution on hillslopes and in stream channels. Slopes within most measured erosion sites are above theoretical and observed debris-flow thresholds. We observed significant erosion of hillslopes and limited deposition on hillslopes and in stream channels. Sediment delivery ratios during time periods with net erosion averaged 0.73. We determined, consistent with previous field observations, that debris flows originating from moraines are a primary erosion mechanism in proglacial zones on Mount Baker. Time series measurements indicate that temporal variability in erosion rates is associated with climate oscillations, with higher erosion rates during cooler-wetter periods. Basin-wide sediment yield is positively correlated with lithology (r² = 0.54), hillslope angle (r² = 0.52), drainage area (r² = 0.82), and negatively correlated with stream channel slope (r² = 0.67). Topographic differences between high and low yielding basins indicate that spatial variability in erosion on Mount Baker is sensitive to Pleistocene and Holocene glacial and volcanic activity. Specific sediment yields in six basins averaged 4600 ton/km²/yr, consistent with global measurements in glacierized catchments. Specific sediment yield decreased with increasing basin area, with total loads in the downstream main stem Nooksack River estimated between 480 and 820 ton/km²/yr. Proglacial sediment yields account for between 18 and 32 % of total sediment load in the main stem Nooksack River and exceed contributions by bluff and terrace erosion, which account for between 8 and 13 % of total load. Our findings indicate that erosion in glacierized basins is sensitive to decadal climate oscillations and that high proglacial sediment yields provide an important contribution to river systems downstream, particularly in catchments where upland topography and lithology is favorable.

Released September 13, 2023 13:33 EST

2023, Frontiers in Microbiology (14)

Corinne Wiesner-Friedman, Rachelle Elaine Beattie, Jill R. Stewart, Krassimira R. Hristova, Marc L. Serre

Introduction: Antimicrobial resistance (AMR) is an increasing public health concern for humans, animals, and the environment. However, the contributions of spatially distributed sources of AMR in the environment are not well defined.

Methods: To identify the sources of environmental AMR, the novel microbial Find, Inform, and Test (FIT) model was applied to a panel of five antibiotic resistance-associated genes (ARGs), namely, erm(B), tet(W), qnrA, sul1, and intI1, quantified from riverbed sediment and surface water from a mixed-use region.

Results: A one standard deviation increase in the modeled contributions of elevated AMR from bovine sources or land-applied waste sources [land application of biosolids, sludge, and industrial wastewater (i.e., food processing) and domestic (i.e., municipal and septage)] was associated with 34–80% and 33–77% increases in the relative abundances of the ARGs in riverbed sediment and surface water, respectively. Sources influenced environmental AMR at overland distances of up to 13 km.

Discussion: Our study corroborates previous evidence of offsite migration of microbial pollution from bovine sources and newly suggests offsite migration from land-applied waste. With FIT, we estimated the distance-based influence range overland and downstream around sources to model the impact these sources may have on AMR at unsampled sites. This modeling supports targeted monitoring of AMR from sources for future exposure and risk mitigation efforts.

Released September 13, 2023 13:10 EST

2023, Journal of Great Lakes Research

Samuel Pecoraro, Peter C. Esselman, Timothy P. O'Brien, Steve A. Farha, David Warner

Acoustic seabed classification (ASC) is an important method for understanding landscape-level physical and biological patterns in the aquatic environment. Bottom habitats in the Laurentian Great Lakes are poorly mapped to date, and will require a variety of contributors and data sources to complete. We repurposed a long-term split-beam echosounder dataset gathered for purposes of fisheries assessment to estimate lakebed properties utilizing unsupervised classification of echo return data. We interpreted first echo properties representing lakebed hardness and roughness to define and map three statistically supported lakebed classes revealed through cluster analysis. Our results indicate coherent and logical class boundaries and suggest that the dataset has promise for expanded use in ASC. To improve inferences using repeated measures, future work should focus on collecting ground truth information for areas previously surveyed and on collecting concurrent ground truth information when sampling acoustic data moving forward.

Released September 13, 2023 09:30 EST

2023, Environmental Science and Technology Letters

Sarah E. Janssen, Christopher James Kotalik, Collin Eagles-Smith, Gale B. Beaubien, Joel C. Hoffman, Greg Peterson, Marc A. Mills, David Walters

The transfer of aquatic contaminants, including mercury (Hg), to terrestrial food webs is an often-overlooked exposure pathway to terrestrial animals. While research has implemented the use of shoreline spiders to assess aquatic to terrestrial Hg transfer, it is unclear whether Hg sources, estimated from isotope ratios, can be successfully resolved to inform site assessments and remedy effectiveness. To examine aquatic to terrestrial Hg transfer, we collected shoreline spiders (Tetragnatha spp.) and aquatic insect larvae (suborder Anisoptera) across a mosaic of aquatic and shoreline habitats in the St. Louis River and Bad River, tributaries to Lake Superior. The fraction of industrial Hg in sediments was reflected in the δ²⁰²Hg values of aquatic dragonfly larvae and predatory fish, connecting benthic Hg sources to the aquatic food web. Shoreline spiders mirrored these aquatic Hg source signatures with highly positive correlations in δ²⁰²Hg between tetragnathids and dragonfly larvae (r² = 0.90). Further assessment of different spider taxa (i.e., araneids and pisaurids) revealed that differences in prey consumption and foraging strategies resulted in isotope differences, highlighting the importance of spider taxa selection for Hg monitoring efforts.

Released September 13, 2023 07:19 EST

2023, Global Ecology and Conservation (46) 13 pages

Lawrence Igl, Deborah A. Buhl, Max Post van der Burg, Douglas H. Johnson

Released September 13, 2023 06:55 EST

2023, BMC Ecological Evolution (23)

Gary M. Bucciarelli, Sierra J. Smith, Justin J. Choe, Phoebe D. Shin, Robert N. Fisher, Lee B. Kats

Background

Biodiversity is generally reduced when non-native species invade an ecosystem. Invasive crayfish, Procambarus clarkii, populate California freshwater streams, and in the Santa Monica Mountains (Los Angeles, USA), their introduction has led to trophic cascades due to omnivorous feeding behavior and a rapid rate of population growth. The native California newt, Taricha torosa, possesses a neurotoxin, tetrodotoxin (TTX), that affects freshwater animal behavior. Given P. clarkii has a limited evolutionary history with TTX, we hypothesized that TTX may affect crayfish feeding behaviors. To determine if TTX affects P. clarkii behavior, we measured cumulative movement and various feeding behaviors of P. clarkii exposed to (i) waterborne, ecologically realistic concentrations of TTX (~ 3.0 × 10^− 8 moles/L), (ii) an anuran chemical cue to account for intraguild cues, or (iii) a T. torosa chemical cue with quantitated TTX in it (~ 6.2 × 10^− 8 moles/L).

Results

We found that the presence of TTX in any form significantly reduced crayfish movement and decreased the amount of food consumed over time. Crayfish responses to the anuran treatment did not significantly differ from controls.

Conclusion

Our laboratory results show that naturally occurring neurotoxin from native California newts limits invasive crayfish foraging and feeding rates, which may play a role in preserving local stream ecosystems by limiting invasive crayfish behaviors that are detrimental to biodiversity.

Released September 12, 2023 19:46 EST

2023, Scientific Investigations Report 2023-5087

Gregory E. Granato, Alana B. Spaetzel, Lillian C. Jeznach

The Stochastic Empirical Loading and Dilution Model (SELDM) was designed to help quantify the risk of adverse effects of runoff on receiving waters, the potential need for mitigation measures, and the potential effectiveness of such management measures for reducing these risks. SELDM is calibrated using representative hydrological and water-quality input statistics. This report by the U.S. Geological Survey, in cooperation with the Federal Highway Administration and the Connecticut, Massachusetts, and Rhode Island Departments of Transportation, documents approaches for assessing flows, concentrations, and loads of highway- and urban-runoff and receiving-stream stormwater in southern New England with SELDM. In this report, the term “urban runoff” is used to identify stormwater flows from developed areas with impervious fractions ranging from 10 to 100 percent without regard to the U.S. Census Bureau designation for any given location. There are more than 48,000 delineated road-stream crossings in southern New England, but because there are relatively few precipitation, streamflow, and water-quality monitoring sites in this area, methods were needed to simulate conditions at unmonitored sites. This report documents simulation methods, methods for interpreting stochastic model results, sensitivity analyses to identify the most critical variables of concern, and examples demonstrating how simulation results can be used to inform scientific decision-making processes. Results of 7,511 SELDM simulations were used to do the sensitivity analyses and provide information decisionmakers can use to address runoff-quality issues in southern New England and other areas of the Nation.

The sensitivity analyses indicate the relatively strong effect of input variables on variations in output results. These analyses indicate that highway and urban runoff quality and upstream water-quality statistics that vary considerably from site to site have the greatest effect on simulated results. Further data are needed to improve available water-quality statistics, and because the number of monitored sites will never approach the number of sites of interest for water-quality management, research is needed to identify methods to select statistics for unmonitored sites and quantify the uncertainties in the selection process. Hydrologically, prestorm streamflows with and without zero flows are the most sensitive and therefore the most important hydrologic variables to quantify. Results of analyses also are sensitive to statistics used for simulating structural best management practices.

Although the focus of the report is on data, statistics, simulation methods, and methods to interpret stochastic simulations, the examples in this report provide results that can be used to inform scientific decision-making processes. The results of 441 simulations that provide regional and site-specific highway and urban runoff yields across southern New England can be used for total maximum daily load analyses. The example stormwater load analysis done for 16 tributaries of the Narragansett Bay demonstrates that highway nitrogen loads are a small fraction of stormwater loads (about 3.6 percent), and a much smaller fraction of all nitrogen loads to the bay, primarily because highways have a small footprint on the land. Examples evaluating the potential effectiveness of end-of-pipe treatment indicate that offsite treatment is warranted in developed areas, and land conservation may be an effective mitigation strategy. The results of these analyses are consistent with conclusions from other simulation and monitoring studies.

Released September 12, 2023 19:45 EST

2023, Scientific Investigations Report 2023-5076

Amanda D. Stoltz, Amanda E. Cravens, Nicole M. Herman-Mercer, Chung Yi Hou

The purpose of this study is to increase understanding of how the U.S. Geological Survey (USGS) is developing decision-support tools (DSTs) by documenting successes and barriers across all levels of USGS scientific tool creation and outreach. These findings will help streamline future tool design and development processes. We provide a synthesis of lessons learned and best practices across a spectrum of USGS decision-support efforts to, A, provide guidance to future efforts and, B, identify knowledge gaps and opportunities for knowledge transfer and integration. We present this information as five guiding principles for those striving to create effective DSTs. These principles are: (1) use an adaptive, iterative design process, (2) collaborate across disciplines and organizations, (3) engage with the target users of the tool, (4) develop an empirical understanding of use and usability, and (5) plan for the tool’s full life span. By providing guidance on how effective DSTs are realized at every phase of development (from planning to maintenance), these principles provide a starting point to improve the process of designing DSTs and thus help further the USGS mission of delivering actionable science.

Released September 12, 2023 15:12 EST

2023, Techniques and Methods 8-D2

James J. Wamboldt

Using manufactured baits to attract fish to passive gear is common practice in fisheries management. The most common method is using hoop nets baited with soybean cakes or waste cheese to increase captures of multiple catfish species; however, these techniques are limited to how often bait is added, the type of bait, gear compatibility, and oversaturation of bait during soak time. The U.S. Geological Survey developed a technique to deliver various types of manufactured, pelleted baits over multiple scenarios and traditional passive gears. A floating platform designed with a dispenser can be constructed easily and allows for the automatic application of varying quantities and sizes of bait. Bait platforms can be modified for use in lakes and rivers where water fluctuations are common. Unlike traditional baiting techniques, these platforms can be positioned over or near any type of gear and release bait as many as nine times daily. Programmed release of bait multiple time a day can be useful to target fish activity during specific hours and can allow for sustained application without bait oversaturation or deterioration from long soak times. This report describes the design of a bait delivery platform developed for deployment in the Sandusky River in Ohio for the removal of Ctenopharyngodon idella (Valenciennes, 1844; grass carp) during 2021 and 2022.

Released September 12, 2023 13:50 EST

2023, General Information Product 226

Mona Khalil, Sally House, Melanie J. Steinkamp, Mark Wimer, David H. Hu, Michael J. Adams

Executive Summary

Our nation’s fish and wildlife species face increasingly complex threats and challenges. Ensuring a healthy future for these species benefits all Americans, contributing to the abundance of our food supply, the well-being of diverse cultures and communities, and the future of biodiverse ecosystems. The U.S. Geological Survey Species Management Research Program (SMRP) plays a critical role in achieving that future by delivering targeted research and foundational scientific services needed to conserve fish and wildlife in a changing world.

Released September 12, 2023 12:49 EST

2023, Open-File Report 2023-1071

Julie L. Yee, Joseph A. Tomoleoni, Michael C. Kenner, Jessica A. Fujii, Gena B. Bentall, Michelle M. Staedler, Brian B. Hatfield

The population of southern sea otters (Enhydra lutris nereis) at San Nicolas Island, California, has been monitored annually since the translocation of 140 southern sea otters to the island was completed in 1990. Monitoring efforts have varied in frequency and type across years. In 2017, the U.S. Navy and the U.S. Fish and Wildlife Service initiated a southern sea otter monitoring and research plan to determine the effects of military readiness activities on the growth or decline of the southern sea otter population at San Nicolas Island. The southern sea otter is the only subspecies of sea otter in California (hereafter, “sea otter"). The monitoring program, at its basic level, includes seasonal surveys of population abundance, distribution, and foraging activity. From 2020 to 2023, we measured a 10-percent per annum increase in population abundance (95-percent confidence interval =0–20 percent), with 146 total individuals as of April 2023. Coinciding with the recent population growth, the sea otter distribution, which previously tended to concentrate on the island’s west end during 2003–2006 before shifting toward more use in the north and south sides during 2017–2019, appears to have shifted again during 2020–2023 to concentrate at the island’s east end. Forage data were collected between February 2020 and April 2023. There was a total of 773 forage dives in 60 forage bouts, with most of the identified prey on successful dives (n=401) recorded as sea urchins (66 percent), followed by bivalves (15 percent), snails (12 percent), and crabs (5.2 percent). Two lobsters and three abalone also were identified among the sea otter prey. Estimates of energy intake rates averaged 14.0 kilocalories per minute (95-percent confidence interval =10.8–17.2 kilocalories per minute). Monitoring data from the past two decades indicate that sea otters at San Nicolas Island have maintained a steady pattern of energy intake and population growth characteristic of a robust population, including a sixfold growth between 2000 and 2023. There was no conclusive evidence of density-dependent effects based on these patterns; however, estimates of energy intake rates for 2020–2023 were slightly lower than previous estimates from 2017 to 2019. Additionally, subtidal monitoring results at four sites around San Nicolas Island indicated that counts of purple sea urchins (Strongylocentrotus purpuratus) have increased between 2003 and 2023, whereas sea otter foraging surveys completed during the same period revealed that some sea otters have shifted toward higher consumption of purple sea urchins and bivalves compared to red sea urchins (S. fransicanus), which generally are the preferred larger prey of sea otters. These results contribute to the understanding of population dynamics and to the conservation and planning of future monitoring and research of sea otters at San Nicolas Island.

Released September 12, 2023 10:25 EST

2023, Journal of the American Water Resources Association

Amanda E. Cravens, Julia B. Goolsby, Theresa Jedd, Deborah J. Bathke, Shelley Crausbay, Ashley E Cooper, Jason Dunham, Tonya Haigh, Kimberly R. Hall, Michael J. Hayes, Jamie McEvoy, Rebecca L Nelson, Markéta Poděbradská, Aaron R. Ramirez, Elliot Wickham, Dionne Zoanni

Institutional authority and responsibility for allocating water to ecosystems (“ecologically available water” [EAW]) is spread across local, state, and federal agencies, which operate under a range of statutes, mandates, and planning processes. We use a case study of the Upper Missouri Headwaters Basin in southwestern Montana, United States, to illustrate this fragmented institutional landscape. Our goals are to (a) describe the patchwork of agencies and institutional actors whose intersecting authorities and actions influence the EAW in the study basin; (b) describe the range of governance mechanisms these agencies use, including laws, policies, administrative programs, and planning processes; and (c) assess the extent to which the collective governance regime creates gaps in responsibility. We find the water governance regime includes a range of nested mechanisms that in various ways facilitate or hinder the governance of EAW. We conclude the current multilevel governance regime leaves certain aspects of EAW unaddressed and does not adequately account for the interconnections between water in different parts of the ecosystem, creating integrative gaps. We suggest that more intentional and robust coordination could provide a means to address these gaps.

Released September 12, 2023 10:25 EST

2023, Circular 1510

Eric D. Anderson, Jennifer R. Erxleben, Sharon L. Qi, Adrian P. Monroe, Katharine G. Dahm

Executive Summary

The U.S. Geological Survey carries out a wide variety of multidisciplinary science projects through the Bureau’s regions, mission areas, programs, and science centers. However, this structure can limit interactions among individual scientists, segregate data holdings, and make it difficult to apply holistic, interdisciplinary science. In addition, technological advances in sensors, data storage and analysis, computing power, and networking have resulted in an exponential growth in the volume, variety, and complexity of data. To address some of these challenges, the U.S. Geological Survey initiated the Colorado River Basin Actionable and Strategic Integrated Science and Technology (ASIST) pilot project to facilitate interdisciplinary science in the drought-stricken basin and apply information management and technology (IMT) resources that can be used to deliver actionable science efficiently and effectively.

In fiscal year 2021, the Data Management and Advanced Technology subgroup of the ASIST pilot project worked toward developing an IMT plan that includes several advanced IMT solutions that are being implemented Bureau-wide by the Office of the Associate Chief Information Officer. This plan identifies applications, opportunities, and steps to leverage new and existing technologies, data, models, and knowledge to support integrated science projects across the Colorado River Basin. The subgroup also created an inventory of available IMT resources and their locations. The Colorado River Basin ASIST pilot project also developed a multiyear approach to build capacity for supporting integrated science projects in the Colorado River Basin, which provides an advanced IMT framework for expediting the production of interdisciplinary science related to the basin.

Released September 12, 2023 08:40 EST

2023, Bulletin of the Seismological Society of America

Adam T. Ringler, Robert E. Anthony, Brian Shiro, Toshiro Tanimoto, David C. Wilson

An increase in seismic stations also having microbarographs has led to increased interest in the field of seismoacoustics. A review of the recent advances in this field can be found in Dannemann Dugick et al. (2023). The goal of this note is to draw the attention of the readers of Dannemann Dugick et al. (2023) to several additional interactions between the solid Earth and atmosphere that have not been classically considered in the field of seismoacoustics. The 15 January 2022 Hunga Tonga–Hunga Ha‘api eruption produced acoustic gravity waves that were recorded globally. For example, the Lamb wave from this eruption produced early‐arriving and long‐lasting tsunami waves. This eruption also provided globally recorded coupling of atmospheric modes with solid Earth modes, providing another example of the complex interactions that can occur at the boundary between the atmosphere and the solid Earth. Even in the absence of large atmospheric signals, collocated pressure sensors at seismic stations can be a useful tool for estimating the local substructure, such at V_S30, the average shear velocity of the upper 30 m. Finally, at low frequencies, it is possible to use pressure records to correct out atmospheric disturbances recorded on seismometers. We briefly review the aforementioned, nontraditional seismoacoustic topics that we feel are important to consider as part of the full suite of interactions occurring between the solid Earth and atmosphere.

Released September 12, 2023 07:03 EST

2023, Marine and Coastal Fisheries: Dynamics, Management, and Ecosystem Science (15)

Kristen A. Anstead, John A. Sweka, Linda Barry, Eric M. Hallerman, David R. Smith, Natalie Ameral, Michael Schmidtke, Richard A. Wong

Objective

This paper applies a catch multiple survey analysis (CMSA) to Atlantic horseshoe crabs Limulus polyphemus in the Delaware Bay to generate robust population estimates for harvest management. Currently, horseshoe crabs along the U.S. Atlantic coast are harvested as bait for other fisheries and collected for their blood, which is used in a biomedical industry. The Delaware Bay is home to the largest population of horseshoe crabs and is a significant stopover for shorebirds to rebuild energy by consuming horseshoe crab eggs prior to completing their northward migration. To address this interrelationship, the Adaptive Resource Management (ARM) Framework has been used since 2013 to ensure that horseshoe crab harvest within the region takes into account the forage needs of migratory birds. Since its inception, the ARM Framework has used a single trawl survey's swept area-based population estimates of horseshoe crab relative abundance and a theoretical population model developed primarily from literature-derived values. With more data collected in the region in recent years and other sources of mortality that can now be quantified, a catch survey model can provide horseshoe crab population estimates going forward.

Methods

A CMSA was used to estimate male and female horseshoe crab population size for 2003–2021 using all quantifiable sources of mortality and three fishery-independent indices of abundance.

Result

The CMSA results indicated that adult abundance of male and female horseshoe crabs was stable from 2003 to 2013 and then began to increase through 2017, a result that is consistent with stock rebuilding following a period of harvest restrictions as recommended by the ARM Framework. Population estimates were lower in recent years but remained above the levels estimated before implementation of the ARM Framework. In 2021, the CMSA estimated that there were over 6 million mature females and nearly 16 million mature male horseshoe crabs in the region.

Conclusion

The CMSA provides the best and most comprehensive population estimates of horseshoe crabs in Delaware Bay and will improve modeling efforts within the ARM Framework going forward.

Released September 11, 2023 15:19 EST

2023, Open-File Report 2023-1065

Jonathan Felis, Josh Adams, Benjamin H. Becker

Marbled Murrelets (Brachyramphus marmoratus) have been listed as “endangered” by the State of California and “threatened” by the U.S. Fish and Wildlife Service since 1992 in California, Oregon, and Washington. Information regarding murrelet abundance, distribution, and habitat associations is critical for risk assessment, effective management, evaluation of conservation efficacy, and ultimately, the meeting of Federal- and State-mandated recovery efforts. From 1999 to present, line-transect surveys have been performed to estimate at-sea abundance and reproductive output of Marbled Murrelets in the marine environment in U.S. Fish and Wildlife Service Conservation Zone 6 (San Francisco Bay to Point Sur in central California). Using this long-term annual time series, we developed a new and comprehensive analytical framework to estimate annual murrelet abundance and trend at sea, evaluated the effectiveness of spatial and temporal components of the monitoring study design, assessed two measures of annual murrelet reproductive output, and developed new spatial models to map murrelet at-sea density and estimate model-based annual at-sea abundances. The long-term average, design-based after-hatch-year (AHY) abundance estimate for the study area was 376 murrelets (range: 163–586 annually), and we did not detect any significant trend during the 23 years of monitoring. Spatial-model-based AHY abundance estimates were similar to design-based estimates but with smaller estimated variance. The AHY murrelets were most abundant nearshore, with little annual variation; alongshore, distribution was more annually variable, and some long-term hotspots occurred, particularly around Point Año Nuevo. The AHY murrelet densities were greatest in July and least in June and August. The long-term average hatch-year (HY) abundance estimate was 13 murrelets (range: 0–31 annually), and the long-term average HY:AHY ratio was 0.052; both metrics indicated similar interannual patterns. Evidence of a significant trend in either metric of reproductive output was not detected; although large overlap among interannual abundance and ratio estimates at the 95-percent confidence interval level made it difficult to evaluate interannual differences. Despite the apparent long-term stability in murrelet abundance in this region from 1999 to 2021, future long-term annual monitoring at sea will be critical to determine if the large-scale August 2020 CZU Santa Cruz Mountain wildfire that occurred adjacent to our study area affects local murrelet at-sea abundance and distribution. We also evaluated potential changes to survey and analytical design that could benefit this monitoring program in the future. Results indicated that eliminating the offshore stratum, focusing more effort on the nearshore stratum, and doing fewer surveys focused on a narrower timeframe could maintain or improve AHY trend estimates while preserving the ability to compare them to past years.

Released September 11, 2023 09:13 EST

2023, Proceedings of the National Academy of Sciences (120)

Barbara A. Han, Kush R. Varshney, Shannon L. LaDeau, Ajit Subramaniam, Kathleen C. Weathers, Jacob Aaron Zwart

Research in both ecology and AI strives for predictive understanding of complex systems, where nonlinearities arise from multidimensional interactions and feedbacks across multiple scales. After a century of independent, asynchronous advances in computational and ecological research, we foresee a critical need for intentional synergy to meet current societal challenges against the backdrop of global change. These challenges include understanding the unpredictability of systems-level phenomena and resilience dynamics on a rapidly changing planet. Here, we spotlight both the promise and the urgency of a convergence research paradigm between ecology and AI. Ecological systems are a challenge to fully and holistically model, even using the most prominent AI technique today: deep neural networks. Moreover, ecological systems have emergent and resilient behaviors that may inspire new, robust AI architectures and methodologies. We share examples of how challenges in ecological systems modeling would benefit from advances in AI techniques that are themselves inspired by the systems they seek to model. Both fields have inspired each other, albeit indirectly, in an evolution toward this convergence. We emphasize the need for more purposeful synergy to accelerate the understanding of ecological resilience whilst building the resilience currently lacking in modern AI systems, which have been shown to fail at times because of poor generalization in different contexts. Persistent epistemic barriers would benefit from attention in both disciplines. The implications of a successful convergence go beyond advancing ecological disciplines or achieving an artificial general intelligence—they are critical for both persisting and thriving in an uncertain future.

Released September 11, 2023 06:41 EST

2023, Journal of Applied Volcanology (12)

Jan Lindsay, Danielle Charlton, Mary Ann T. Clive, Daniel Bertin, Sarah E. Ogburn, Heather M. Wright, John W. Ewert, Eliza S. Calder, Bastian Steinke

The IAVCEI Working Group on Hazard Mapping has been active since 2014 and has facilitated several activities to enable sharing of experiences of how volcanic hazard maps are developed and used around the world. One key activity was a global survey of 90 map makers and practitioners to collect data about official, published volcanic hazard maps and how they were developed. The survey asked questions about map content, design, and input data, as well as about the map development process and key lessons learned. Here we present the results of this global survey, which are then used to quantitatively describe and summarise current practices in volcanic hazard map development.

We received entries related to 89 volcanic hazard maps (78% long-term/background maps and 22% short-term/crisis hazard maps), covering a total of 80 volcanoes across 28 countries. Although most maps captured in the survey are volcano-scale maps of stratovolcanoes that show similar types of content, such as primary hazard footprints or zones, they vary greatly in input data, communication style, format, appearance, scale, content, and visual design. This diversity stems from a range of factors, including differences in map purpose, the methodology used, the level of understanding of past eruptive history, the prevailing scientific and cartographic practice at the time, the state of volcanic activity, and variations in culture, national map standards and legal requirements.

Experiences and lessons shared by our respondents can be divided into six main themes: map design considerations; the process of map development; map audience and map user needs; hazard assessment approach; map availability and accessibility; and external (e.g., political) influences. Insights shared included the importance of: visual design elements, map testing and evaluation, working with stakeholders and end users to improve a map’s efficacy and relevance, and considering possible unanticipated uses of hazard maps. These free-form text insights (i.e., responses to open-ended questions) from map makers and practitioners familiar with the maps lend depth and clarity to our results. They provide a rich complement to our more quantitative analysis of design elements and of approaches used to determine and delineate map zones.

Results from our global survey of hazard map makers and practitioners, together with insights from other key initiatives of the Working Group on Hazard Mapping such as the Volcanic Hazard Maps Database (VHMD; https://volcanichazardmaps.org/), provide a snapshot of the wide variety of volcanic hazard maps generated over the past decades, and improve our understanding of the diversity across volcanic hazard mapping practices. These initiatives represent important steps towards fulfilling the aims of the Working Group, namely, to construct a framework for a classification scheme for volcanic hazard maps and to promote harmonized terminology, as well as to identify and categorise good practices and considerations for volcanic hazard mapping.

Released September 10, 2023 10:48 EST

2023, Estuarine, Coastal and Shelf Science (293)

Gregg Snedden

Though the importance of Earth's internal climate modes such as the El Niño-Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO) to regional-scale climate variability is well recognized, the degree to which these oscillations are reflected by spatio-temporal salinity variability over interannual timescales in estuaries is less understood. Here an 11-year continuous salinity monitoring dataset spanning 223 stations across Louisiana's coastal wetlands along the northern Gulf of Mexico is examined with empirical orthogonal function (EOF) analysis to identify dominant modes of interannual variability in the salinity field. The first EOF mode accounts for 72% of the variance in the salinity field and captures a domain-wide pattern where salinities vary in-phase through space in response to local precipitation anomalies occurring in the vicinity of the study area. This local precipitation anomaly is positively correlated with ENSO (Nino3.4 index), consistent with the El Niño – wet (La Niña – dry) precipitation teleconnection that is prevalent throughout the northern Gulf of Mexico coast. The second EOF mode, which accounts for 13% of the variance in the salinity field, is expressed primarily in the marshes across the lower reaches of the Mississippi River deltaic plain (MRDP). EOF2 is anticorrelated with annual Mississippi River discharge anomaly such that salinities in the lower MRDP decrease as discharge increases, pointing to enhanced advection of fresh river plume waters over the shelf into the estuary via estuary-ocean exchange during years of anomalously high river discharge. Mississippi River discharge anomaly is positively correlated with the NAO at a one-year time lag, through a teleconnection with precipitation throughout much of the central region of the Mississippi River drainage basin. Together, these findings indicate that most of the interannual salinity variability across Louisiana's coastal wetlands can be linked to climate variability through teleconnections with precipitation. Incorporating these dynamics into restoration planning, monitoring, and adaptive management efforts may help constrain background environmental variation and better isolate restoration effects.

Released September 08, 2023 15:16 EST

2023, Open-File Report 2023-1063

Laura A. Stern, Stephen H. Kirby

The U.S. Geological Survey (USGS) Clathrate Hydrate Properties Project, active from 1993 to 2022 in Menlo Park, California, stemmed from an earlier project on the properties of planetary ices supported by the National Aeronautics and Space Administration’s (NASA’s) Planetary Geology and Geophysics Program. We took a material science approach in both projects, emphasizing chemical purity of samples, having controlled grain size and grain texture, and having verified crystal structures and phase relations. A foundational contribution from our USGS Gas Hydrate Properties Laboratory (GHPL) was in demonstrating the ability to reproducibly create such pure clathrate hydrate samples for study. Clathrate sample synthesis was achieved by heating sieved and weighed pure granular water ice in the presence of cold clathrate-forming gas or liquid. During heating, the ice melts at the grain scale and reacts with the gas to form clathrate. The resulting material has the desired uniformity and purity, with known intergranular porosity; our subsequent measurements showed that these clathrates exhibited the established clathrate structures and phase relations. This novel synthesis method was successful in creating clathrates of pure methane, ethane, propane, carbon dioxide, and multi-component gases. By mixing sand or silt with granular ice, we were also able to make clathrate-sediment aggregates with controlled grain textures. This simple method, adopted by many others in the community, permitted us to measure the physical and chemical properties of well-characterized and well-crystallized clathrates and clathrate/sediment aggregates. At about the same time, we adapted conventional scanning electron microscopy to cryogenic conditions for analysis of grain-scale characteristics of clathrates made in the GHPL as well as those collected from nature by drill core. The uniformity and reproducibility of our samples also allowed us to investigate how clathrates respond to environmental changes in chemistry, temperature, and pressure: we measured chemical exchange rates with dissolved gas species—such as noble gases and chlorofluorocarbons—as well as rates of clathrate dissolution and decomposition. These advances include the first accurate mapping of the conditions that promote the remarkable process of “anomalous preservation” at room pressure, a metastability that offers potential application for low-cost and safe transportation of natural gas from gas fields far from pipelines.

Another advancement stemming from the GHPL was the compaction of as-synthesized porous clathrates to nearly full density by applying external pressure using three different techniques. Compaction allows for high-accuracy measurements of many fundamental physical and chemical properties of these materials, such as elastic wavespeeds and moduli, complete thermal properties, decomposition rates, thermal expansion, and clathrate equations of state. These properties and others, in turn, have helped USGS scientists to interpret geophysical well logs and active geophysical surveys, as well as model the rates of gas production from hydrate deposits in nature.

Studying this class of icy minerals that occur in abundance on Earth and in the outer solar system has been a fascinating laboratory journey. Here, we summarize the history and major findings of the USGS GHPL in Menlo Park, including both in-house research as well as findings from the synergistic collaborations with other agencies and institutes that were key to the success of our laboratory. The Menlo Park GHPL was more formally incorporated within the USGS Gas Hydrates Project, a collaboration among multiple USGS Science Centers, in the early 2000s under the leadership of Deborah Hutchinson, and now under the leadership of Carolyn Ruppel and Timothy Collett.

Released September 08, 2023 08:09 EST

2023, Conservation Science and Practice

Evan H. Campbell Grant, Staci M. Amburgey, Brian Gratwicke, Victor Acosta Chaves, Anat M. Belasen, David Bickford, Carsten Brühl, Natalie E. Calatayud, Nick Clemann, Simon Clulow, Jelka Crnobrnja-Isailovic, Jeff Dawson, David A. De Angelis, C. Kenneth Dodd Jr., Annette Evans, Gentile Francesco Ficetola, Mattia Falaschi, Sergio González-Mollinedo, David M. Green, Roseanna Gamlen-Greene, Richard A. Griffiths, Brian J. Halstead, Craig Hassapakis, Geoffrey Heard, Catharina Karlsson, Tom Kirschey, Blake Klocke, Tiffany A. Kosch, Sophia Kusterko Novaes, Luke Linhoff, John C. Maerz, Brittany A. Mosher, Katherine M O'Donnell, Leticia M. Ochoa-Ochoa, Deanna H. Olson, Kristiina Ovaska, J. Dale Roberts, Aimee J. Silla, Tariq Stark, Jeanne Tarrant, R. Upton, Judit Vörös, Erin L. Muths

The problem of global amphibian declines has prompted extensive research over the last three decades. Initially, the focus was on identifying and characterizing the extent of the problem, but more recently efforts have shifted to evidence-based research designed to identify best solutions and to improve conservation outcomes. Despite extensive accumulation of knowledge on amphibian declines, there remain knowledge gaps and disconnects between science and action that hamper our ability to advance conservation efforts. Using input from participants at the ninth World Congress of Herpetology, a U.S. Geological Survey Powell Center symposium, amphibian on-line forums for discussion, the International Union for Conservation of Nature Assisted Reproductive Technologies and Gamete Biobanking group, and respondents to a survey, we developed a list of 25 priority research questions for amphibian conservation at this stage of the Anthropocene. We identified amphibian conservation research priorities while accounting for expected tradeoffs in geographic scope, costs, and the taxonomic breadth of research needs. We aimed to solicit views from individuals rather than organizations while acknowledging inequities in participation. Emerging research priorities (i.e., those under-represented in recently published amphibian conservation literature) were identified, and included the effects of climate change, community-level (rather than single species-level) drivers of declines, methodological improvements for research and monitoring, genomics, and effects of land-use change. Improved inclusion of under-represented members of the amphibian conservation community was also identified as a priority. These research needs represent critical knowledge gaps for amphibian conservation although filling these gaps may not be necessary for many conservation actions.

Released September 08, 2023 07:11 EST

2023, Quaternary Science Reviews (317)

Heikki Seppä, Marit-Solveig Seidenkrantz, Beth Elaine Caissie, Marc Macias Fauria

Polar bear (Ursus maritimus) is the apex predator of the Arctic, largely dependent on sea-ice. The expected disappearance of the ice cover of the Arctic seas by the mid 21st century is predicted to cause a dramatic decrease in the global range and population size of the species. To place this scenario against the backdrop of past distribution changes and their causes, we use a fossil dataset to investigate the polar bear's past distribution dynamics during the Late Glacial and the Holocene. Fossil results indicate that during the last deglaciation, polar bears were present at the southwestern margin of the Scandinavian Ice Sheet, surviving until the earliest Holocene. There are no Arctic polar bear findings from 8000–6000 years ago (8–6 ka), the Holocene's warmest period. However, fossils that date from 8-9 ka and 5–6 ka suggest that the species likely survived this period in cold refugia located near the East Siberian Sea, northern Greenland and the Canadian Archipelago. Polar bear range expansion is documented by an increase in fossils during the last 4000 years in tandem with cooling climate and expanding Arctic sea ice. The results document changes in polar bear's distribution in response to Late Glacial and Holocene Arctic temperature and sea ice trends.

Released September 08, 2023 06:40 EST

2023, Bulletin of Volcanology (85)

Heather M. Wright, Carolyn L. Driedger, John S. Pallister, Christopher G. Newhall, Michael A. Clynne, John W. Ewert

Released September 07, 2023 12:00 EST

2023, Scientific Investigations Report 2023-5086

Marla H. Stuckey, Matthew D. Conlon, Mitchell R. Weaver

Pennsylvania experienced heavy rainfall on September 1 and 2, 2021, as the remnants of Hurricane Ida swept over parts of the State. Much of eastern and south-central Pennsylvania received 5 to 10 inches of rain, and most of the rainfall fell within little more than 6 hours. Southeastern Pennsylvania experienced widespread, substantial flooding, and the city of Philadelphia and surrounding areas were particularly affected by the flooding. U.S. Geological Survey (USGS) streamgages registered peak streamflows of record at 19 locations, and 52 locations experienced top 5 peak streamflows for the period of record and an annual exceedance probability estimate of at least 10 percent. During this September 2021 flood event, USGS personnel made over 60 streamflow measurements at streamgages in Pennsylvania using direct and indirect methods. Many of those streamflow measurements were made to verify or improve the accuracy, extent, or development of new stage-streamflow relations at streamgages operated by the USGS. After the floodwaters receded, USGS personnel identified and documented a total of 338 high-water marks in Pennsylvania, noting such things as their general description, location, height above land surface, and quality. Many of these high-water marks were used to create five flood-documentation maps for selected communities in southeastern Pennsylvania that experienced substantial flooding because of the remnants of Hurricane Ida. Digital datasets of the inundated areas, mapped boundaries, and water depth are available (Stuckey and Conlon, 2023).

Released September 07, 2023 10:29 EST

2023, Scientific Investigations Map 3506

Benjamin Miller, Benjamin Tobin

Fern Cave in Jackson County, Alabama, is a 15.6-mile-long (25.1-kilometer) cave system, managed by the U.S. Fish and Wildlife Service and Southeastern Cave Conservancy, that has the second highest biodiversity of any cave in the southeastern United States. Groundwater in karst ecosystems is known to be susceptible to impacts from human-induced land-use activities in watersheds that contribute recharge to the groundwater system. To provide the U.S. Fish and Wildlife Service with necessary baseline information on the groundwater flow system in Fern Cave, the U.S. Geological Survey and the Kentucky Geological Survey conducted a series of dye traces during 2019–21 to delineate the watershed recharging the cave system. The dye traces identified two separate streams that flow through the cave and a recharge area of 1.73 square miles (4.48 square kilometers) draining to the cave system. Current land use within the recharge area is dominated by deciduous forest with minimal additional land use types, indicating a low potential for undesirable effects to the cave by anthropogenic sources.

Released September 06, 2023 15:22 EST

2023, Open-File Report 2023-1064

Guy R. Cochrane, Rikk Kvitek, Aaron Cole, Meghan Sherrier, Alia Roca-Lezra, Sean Hallahan, Peter Dartnell

Coastal and Marine Ecological Classification Standard geoform, substrate, and biotic component geographic information system products were developed for the California State waters of south-central California in the region offshore of Morro Bay. The study was motivated by interest in development of offshore wind-energy capacity and infrastructure in Federal waters offshore. The Bureau of Ocean Energy Management, in coordination with the State of California and many other members of the California Intergovernmental Renewable Energy Task Force, issued calls for information in 2018 for the study area offshore of Morro Bay, California. The study area is adjacent to a nuclear power plant (currently scheduled for decommissioning) with a developed electric grid connection, and in an area of high wind resource potential. The Bureau of Ocean Energy Management is the lead agency responsible for planning and leasing in the U.S. Exclusive Economic Zone and funded this project to assess baseline conditions of, and the potential effects on, the seafloor environment. This project, carried out by the U.S. Geological Survey, resulted in three data releases for individual map blocks that are part of the California State Waters Map Series: (1) Offshore of Point Estero, (2) Offshore of Morro Bay, and (3) Offshore of Point Buchon. The study area consists of 341 square kilometers (km²) of multibeam echo sounder (MBES) data acquired by Fugro, Inc., in 2010. Towed camera-sled video was acquired in 2012 to supervise the classification of the MBES data into habitats. There were 935 annotations of organisms and habitat made from 22 video transects. Using video observations of habitat as ground truth, derivatives of the MBES data were classified into 3 seafloor character types (hard-rugged, hard-flat, and soft-flat), 25 modifier groups, and 9 geoforms. The study area substrate is predominantly soft-flat sediment (mud and fine sand) covering 191.3 km² (56.1 percent) of the area. Hard-flat substrate areas, predominantly coarse sediment in scour depressions, cover 52.2 km² (15.3 percent) of the study area. The hard-rugged substrate areas are primarily outcrops of layered sedimentary bedrock and constitute 97.5 km² of the study area (28.6 percent). After classification of bathymetry and backscatter raster images according to substrate, false-positive hard areas produced by noise artifacts were removed by manual editing. Nine geoforms were then identified in the analysis. The predominant geoforms mirror the seafloor character results, shelf geoforms (flat areas covered in soft sediment), rock outcrop geoforms (hard, rugged areas), and scour depression geoforms (flat areas covered in coarse sediment formed by bottom currents).

Released September 06, 2023 10:45 EST

2023, Circular 1511

Teresa J. Newton, Nathan A. Johnson, David H. Hu

Executive Summary

North America is a global center for native freshwater mussel (order Unionida, hereinafter “mussels”) diversity, with more than 350 species. Mussels are among the most imperiled fauna on the planet. Reasons for both local and widespread declines in mussels are mostly unknown, although the threats may include habitat loss and fragmentation, diseases, environmental contaminants, altered flow regimes, migration barriers to larval hosts, non-native species, and climate change.

Over the past three decades, research on mussels has been substantial. Nevertheless, current conservation and management efforts are limited by significant information gaps. For example, the effects of emerging stressors on mussels are largely unknown and identifying when habitats are rehabilitated and suitable for reestablishment of mussels remains challenging. Additionally, historical and current information on the distribution, taxonomy, and life histories are often unreliable or lacking altogether, and more reliable information is needed for many species.

We identified focal research themes, goals, and objectives where research on mussels is needed based on information gaps identified through conversations with resource partners across local, regional, and national organizations. Research on biodiversity seeks to enhance the diversity of mussel species and populations to support healthy aquatic ecosystems. Research on emerging stressors seeks to improve the understanding of how mussel species, populations, and communities respond to emerging stressors, including environmental contaminants and climate change. Research on conservation seeks to enhance the recovery of species and populations and to identify data gaps limiting the conservation of mussels and their habitats. Mussels are in urgent need of proactive conservation because they are an integral part of our natural heritage, enhance biodiversity, and provide vital ecological services that support freshwater ecosystems.

The U.S. Geological Survey (USGS) has been, and continues to be, a leader in mussel research. Although the USGS is well suited to address the broad-scale multidisciplinary research needed to conserve mussels, the USGS has had substantial loss of scientists with mussel expertise over the past 20 years. However, the breadth of the USGS expertise on mussels can be leveraged internally across other USGS mission and program areas and externally across research partners. Given the breadth and scope of the issues facing mussels across the United States, the research themes outlined in this science vision can only be accomplished through extensive collaborations between the USGS and the full spectrum of natural resource partners, including other Federal and State agencies, Tribal organizations, universities, industries, and nongovernmental organizations.

Released September 06, 2023 09:03 EST

2023, Bulletin American Meteorological Society (104) S61-S63

Benjamin M. Kraemer, Hilary A. Dugan, Sofia La Fuente, Michael Frederick Meyer

No abstract available.

Released September 06, 2023 08:13 EST

2023, AGU Advances (4)

Gavin McNicol, Etienne Fluet-Chouinard, Zutao Ouyang, Sarah Knox, Zhang Zhen, Tuula Aalto, Sheel Bansal, Kuang-Yu Chang, Min Chen, Kyle Delwiche, Sarah Feron, Mathias Goeckede, Jinxun Liu, Avni Malhotra, Joe R. Melton, William Riley, Rodrigo Vargas, Kunxiaojia Yuan, Qing Yang, Qing Zhu, Pavel Alekseychik, Mika Aurela, David P. Billesbach, David I. Campbell, Jiquan Chen, Housen Chu, Ankur Desai, Eugenie Euskirchen, Jordan Goodrich, Timothy Griffis, Manuel Helbig, Takashi Hirano, Hiroki Iwata, Gerald Jurasinski, John King, Franziska Koebsch, Randall Kolka, Ken Krauss, Annalea Lohila, Ivan Mammarella, Mats Nilson, Asko Noormets, Walter Oechel, Matthias Peichl, Torsten Sachs, Ayaka Sakabe, Christopher Schulze, Oliver Sonnentag, Ryan C. Sullivan, Eeva-Stiina Tuittila, Masahito Ueyama, Timo Vesala, Eric Ward, Christian Wille, Guan Xhuan Wong, Donatella Zona, Lisamarie Windham-Myers, Benjamin Poulter, Robert B. Jackson

Wetlands are responsible for 20%–31% of global methane (CH₄) emissions and account for a large source of uncertainty in the global CH₄ budget. Data-driven upscaling of CH₄ fluxes from eddy covariance measurements can provide new and independent bottom-up estimates of wetland CH₄ emissions. Here, we develop a six-predictor random forest upscaling model (UpCH4), trained on 119 site-years of eddy covariance CH₄ flux data from 43 freshwater wetland sites in the FLUXNET-CH4 Community Product. Network patterns in site-level annual means and mean seasonal cycles of CH₄ fluxes were reproduced accurately in tundra, boreal, and temperate regions (Nash-Sutcliffe Efficiency ∼0.52–0.63 and 0.53). UpCH4 estimated annual global wetland CH₄ emissions of 146 ± 43 TgCH₄ y⁻¹ for 2001–2018 which agrees closely with current bottom-up land surface models (102–181 TgCH₄ y⁻¹) and overlaps with top-down atmospheric inversion models (155–200 TgCH₄ y⁻¹). However, UpCH4 diverged from both types of models in the spatial pattern and seasonal dynamics of tropical wetland emissions. We conclude that upscaling of eddy covariance CH₄ fluxes has the potential to produce realistic extra-tropical wetland CH₄ emissions estimates which will improve with more flux data. To reduce uncertainty in upscaled estimates, researchers could prioritize new wetland flux sites along humid-to-arid tropical climate gradients, from major rainforest basins (Congo, Amazon, and SE Asia), into monsoon (Bangladesh and India) and savannah regions (African Sahel) and be paired with improved knowledge of wetland extent seasonal dynamics in these regions. The monthly wetland methane products gridded at 0.25° from UpCH4 are available via ORNL DAAC (https://doi.org/10.3334/ORNLDAAC/2253).

Released September 05, 2023 10:19 EST

2023, Environmental Pollution (336)

Arioené Vreedzaam, Paul Ouboter, Ashna D. Hindori-Mohangoo, Ryan F. Lepak, Samantha L. Rumschlag, Sarah E. Janssen, Gwen Landburg, Arti Shankar, Wilco Zijlmans, Maureen Y. Lichtveld, Jeffrey K. Wickliffe

In Suriname, mercury (Hg) use has recently increased because of gold mining, which has put fish-reliant communities (e.g., Indigenous and Tribal) at risk of enhanced Hg exposure through the riverine fish these communities consume. To quantify how the magnitude of these risks change according to location and time, we measured total mercury (HgT) in fish at sites downstream and upstream of an artisanal and small-scale gold mining (ASGM) operation in 2004–2005 and in 2017–2018. We tested whether fish HgT burdens over dynamic ranges were increased. Surprisingly, our findings did not support broadly increased fish Hg burden over time or that proximity to ASGM was diagnostic to fish HgT-burden. Subsequently, we elected to test the HgT stable isotope ratios on a set of freshly collected 2020 fish to determine whether differences in Hg source and delivery pathways might cofound results. We found that remote unmined sites were more susceptible to gaseous elemental Hg deposition pathways, leading to enhanced risk of contamination, whereas ASGM proximate sites were not. These results highlight that elemental mercury releases from ASGM practices may have significant impact on fish-reliant communities that are far removed from ASGM point source contamination.

Released September 05, 2023 09:38 EST

2023, Scientific Investigations Report 2023-5085

Laurel E. Stratton Garvin, Norman L. Buccola, Stewart A. Rounds

Mechanistic models capable of simulating hydrodynamics and water temperature in rivers and reservoirs are valuable tools for investigating thermal conditions and their relation to dam operations and streamflow in river basins where upstream water storage and management decisions have an important influence on river reaches with threatened fish populations. In particular, models allow managers to investigate how new, untried operations or hypothetical structures might influence streamflow and temperature conditions downstream. CE-QUAL-W2 is a two-dimensional (laterally averaged) hydrodynamic water-quality model that has previously been used to investigate the downstream effects of dam operations and other anthropogenic influences on stream temperature in the Willamette River Basin in northwestern Oregon, a region with two populations of fish species designated as threatened under the Endangered Species Act. By linking CE-QUAL-W2 river models to models of upstream, large Willamette Valley Project dams and reservoirs, these models can be used to investigate how dam operations at individual dams can influence streamflow and thermal conditions in downstream river reaches as an integrated system. Integrated model simulations that include the large dams and reservoirs linked to downstream river reaches can help managers develop a better understanding of tradeoffs associated with potential retrofits or operational changes across the multipurpose dams in the Willamette Valley Project, the effect of dam management on downstream tributaries and the Willamette River, and the resulting potential effect on threatened fish populations and habitat conditions.

River models capable of simulating river corridors downstream from U.S. Army Corps of Engineers dams were previously updated and integrated to simulate conditions that occurred from March through October of 2011 (a cool and wet year), 2015 (a hot and dry year), and 2016 (a moderately hot and dry year) using CE-QUAL-W2 version 4.2. These river models encompass the following:

• Coast Fork Willamette and Middle Fork Willamette Rivers, the Row River, and Fall Creek downstream from Cottage Grove, Dexter, Dorena, and Fall Creek Dams, respectively;
• South Fork McKenzie River downstream from Cougar Dam;
• McKenzie River downstream from its confluence with the South Fork McKenzie River;
• South Santiam River downstream from Foster Dam;
• North Santiam River downstream from Big Cliff Dam; and
• Willamette River from its start at the confluence of the Middle Fork Willamette and Coast Fork Willamette Rivers to Willamette Falls (river mile 26.0; near West Linn, Oregon).

This report documents model modifications, boundary condition data sources or estimation methods, and goodness-of-fit statistics for six CE-QUAL-W2 reservoir models and one river model upstream from the existing river models. These models simulate (1) Hills Creek Lake; (2) Lookout Point Lake and Dexter Reservoir on the Middle Fork Willamette River; (3) the Middle Fork Willamette River reach between Hills Creek Dam upstream and Lookout Point Lake downstream; (4) Cougar Reservoir on the South Fork McKenzie River; (5) Green Peter Lake on the Middle Santiam River and Foster Lake on the South Santiam River; and (6) Detroit Lake and (7) Big Cliff Reservoir on the North Santiam River. These CE-QUAL-W2 models were built by a variety of researchers to simulate a range of conditions in past years; this report documents their upgrade to U.S. Geological Survey (USGS) edition 7 of version 4.2 of CE-QUAL-W2 and updates each model to simulate conditions from January through December of 2011, 2015, and 2016. Also included in this report is an explanation of modifications to the CE-QUAL-W2 source code that constitute USGS edition 7 of CE-QUAL-W2 version 4.2. Each of the models described in this report can be run in isolation or linked to downstream models as a “system model” to simulate conditions in tributaries and (or) in the Willamette Valley Project as a whole.

As part of the model updates described in this report, some model parameters were adjusted to improve stability or decrease model error, and boundary conditions including meteorological, hydrologic, and temperature inputs were developed and updated for model years 2011, 2015, and 2016, as necessary. In some cases, the data sources used to drive previous model versions were no longer available, which required the development and checking of new data sources or estimation techniques. Goodness-of-fit statistics for outflow from the dams and in simulated river reaches generally show a good model fit, with the models simulating subdaily water temperatures at most comparable locations with a mean absolute error of generally less than 1 degree Celsius (°C) and a reasonably low bias. Model simulation of the thermal vertical profiles in each reservoir also produced an overall mean absolute error of generally less than 1 °C for all 3 years, with the exception of the Hills Creek Lake Model and the Cougar Reservoir Model in years when the reservoirs did not fill (2015 and 2016). Both of these models have known calibration issues and tend to be sensitive to the choice of certain structural parameters in the model. Overall, the calibration process was focused on obtaining model settings that led to realistic water temperature predictions in all 3 years (2011, 2015, and 2016) without over-calibrating specifically to any single year. A complete investigation of model error for these reservoir submodels was beyond the scope of this investigation but could be undertaken in the future if better model performance for these two reservoirs is desired.

Released September 05, 2023 09:25 EST

2023, Environmental DNA

Rachelle Elaine Beattie, Caren C. Helbing, Jacob J. Imbery, Katy E. Klymus, Jonathan Lopez Duran, Catherine A. Richter, Anita A. Thambirajah, Nathan Thompson, Thea Margaret Edwards

Environmental DNA (eDNA) surveys are a promising alternative to traditional monitoring of invasive species, rare species, and biodiversity. Detecting organism-specific eDNA reduces the need to collect physical specimens for population estimates, and the high sensitivity of eDNA assays may improve detection of rare or cryptic species. However, correlating estimated concentrations of eDNA with species abundance can be difficult due to the many abiotic and biotic factors that influence eDNA persistence and degradation. Here, we assessed the impact of a nitrifier-enriched microbial (NEM) community on the persistence and degradation of Hypophthalmichthys molitrix (silver carp) milt eDNA using experimental aquatic mesocosms and a quantitative PCR approach. The NEM community was cultured from combined sediment and water samples collected from a golf course pond in Columbia, Missouri (USA), and experiments were conducted in the dark at 22°C. We found that the NEM community transformed organic nitrogen from silver carp milt to measurable amounts of nitrate, both in the presence and absence of ammonia nitrogen. Additionally, regardless of ammonia availability, milt eDNA followed a one-phase exponential decay pattern after an initial 24-h plateau in the presence of the NEM community. However, milt eDNA had a shorter half-life (12.5 h) in the absence of exogenous ammonia compared to when ammonia was present (15 h). In sterile mesocosms, eDNA was stable during the 72-h experiment. Together, these results suggest that the presence of microorganisms is necessary for short-term degradation of eDNA. Furthermore, nitrifying microbial communities, which are ubiquitous in most soil and water environments, could limit eDNA persistence in the environment. Understanding the contributions of environmental microbial communities will allow more confidence in sampling design and eDNA result interpretations for biodiversity management applications.

Released September 05, 2023 08:31 EST

2023, Journal of Veterinary Behavior (66)

Sarah R. B. King, Mary J. Cole, Christine Barton, Kathryn A. Schoenecker

The burgeoning population of feral horses in the American west is due to high population growth, resulting from low adult mortality and high foal survival. In two populations of feral horses in western Utah, USA only 15 foals died (5%; mean age <1 month) over a 4-year period. Seven additional foals (age <70 days) were observed separated from their dam, with no return to suckling or associating with the dam (i.e., abandoned). Factors affecting fate of foals were examined by comparing dead and separated foals with siblings (n = 19 dams, n = 32 siblings). Foals becoming separated or dying were observed in all years of the study, were unrelated to horse density, environmental effects, or gather events. There was no effect of dam body condition, parity, or age on foal survival or separation, and no effect of length of time the dam was in a group, whether the foal was born into the same group as conceived, and number of group changes made by the dam while pregnant. Dams of foals that died or were separated were more likely to change groups within 2 months after the foal was first seen, mostly after foal death or separation. Separated foals were near their dam less often, but there was no difference in frequency of social interactions. Separation of foals and dams is a natural occurrence in feral horses and survival likelihood for these foals is high – all separated foals that remained on the range in this study survived.

Released September 05, 2023 08:25 EST

2023, Frontiers in Ecology and the Environment

Joseph Michael Eisaguirre, Perry J. Williams, Xinyi Lu, Michelle L. Kissling, Paul A Schutte, Benjamin P Weitzman, William S. Beatty, George G. Esslinger, Jamie N. Womble, Mevin B. Hooten

The reintroduction and recovery of predators can be ecologically beneficial as well as socially and economically controversial. However, the growth and expansion of predator populations, and thus their ecological, social, and economic impacts, are not static but rather they vary in space and time. We propose a spatiotemporal statistical modeling framework based on ecological diffusion to better inform the ecology and management of recovering predators and their prey. We demonstrate its utility by applying it to a recovering sea otter (Enhydra lutris) population in Southeast Alaska, where sea otters were reintroduced in the late 1960s and have exhibited unprecedented population growth. Estimated parameters yield inferences about movement and population ecology, and our approach provides useful derived quantities, such as local abundance and carrying capacity as well as a quantity we term the equilibrium differential. We used our model to examine how density dependence and carrying capacity of sea otters vary spatially across a region. The diffusion modeling approach we present can be generalized for use in other instances of (re)colonization across taxa to inform management and conservation efforts.

Released September 05, 2023 08:24 EST

2023, Frontiers in Ecology and the Environment

Sarah K. Carter, Travis Haby, Jennifer K. Meineke, Alison C. Foster, Laine E. McCall, Leigh Espy, Megan Gilbert, Jeffrey E. Herrick, Karen Prentice

Public land management agencies in the US are committed to using science-informed decision making, but there has been little research on the types and topics of science that managers need most to inform their decisions. We used the National Environmental Policy Act to identify four types of science information needed for making decisions relevant to public lands: (1) data on resources of concern, (2) scientific studies relevant to potential effects of proposed actions, (3) methods for quantifying potential effects of proposed actions, and (4) effective mitigation measures. We then used this framework to analyze 70 Environmental Assessments completed by the Bureau of Land Management in Colorado. Commonly proposed actions were oil and gas development, livestock grazing, land transactions, and recreation. Commonly analyzed resources included terrestrial wildlife, protected birds, vegetation, and soils. Focusing research efforts on the intersection of these resources and actions, and on developing and evaluating the effectiveness of mitigation measures to protect these resources, could strengthen the science foundation for public lands decision making.

Released September 05, 2023 08:18 EST

2023, Journal of Wildlife Diseases

Jennifer F. Provencher, Alana A. E. Wilcox, Samantha E. J. Gibbs, Lesley-Anne Howes, Mark L. Mallory, Margo J. Pybus, Andrew M. Ramey, Eric T. Reed, Chris Sharp, Catherine Soos, Iga Stasiak, Jim O. Leafloor

A Eurasian lineage highly pathogenic avian influenza virus (HPAIV) of the clade 2.3.4.4b (Goose/Guangdong lineage) was detected in migratory bird populations in North America in December 2021, and it, along with its reassortants, have since caused wild and domestic bird outbreaks across the continent. Relative to previous outbreaks, HPAIV cases among wild birds in 2022 exhibited wider geographic extent within North America and higher levels of mortality, suggesting the potential for population-level impacts. Given the possible conservation implications of HPAIV in wild birds, natural resource managers have sought guidance on actions that may mitigate negative effects of disease among North American bird populations, including modification of existing management practices. Banding of waterfowl is a critical tool for population management for several harvested species in North America, but some banding techniques, such as bait trapping, can lead to increased congregation of waterfowl, potentially altering HPAIV transmission. We used an expert opinion exercise to assess how bait trapping of dabbling ducks in Canada may influence HPAIV transmission and wild bird health. The expert group found that it is moderately likely that bait trapping of dabbling ducks in wetlands will significantly increase the transmission of HPAIV among individual ducks, but there is a low probability that this will result in significant population-level effects on North American dabbling ducks. Considering the lack of empirical work studying how capture and handling methods may change transmission of HPAIV among waterfowl, as well as the importance of bait trapping for waterfowl management in North America, future work should focus on filling knowledge gaps pertaining to the influence of baiting on HPAIV occurrence to better inform banding procedures and management decision making.

Released September 05, 2023 07:24 EST

2023, Water Resources Research (59)

Hannah R. Field, Audrey H. Sawyer, Susan A. Welch, Ryan K. Benefiel, Devan M. Mathie, James M. Hood, Ethan D. Pawlowski, Diana L. Karwan, Rebecca Kreiling, Zackary I. Johnson, Brittany R. Hanrahan, Kevin W. King

Released September 05, 2023 06:35 EST

2023, Environmental Research Letters (18)

Julia Guimond, Casu Demir, Barret L. Kurylyk, Michelle A. Walvoord, James M. McClelland, M. Bayani Cardenas

Released September 04, 2023 07:23 EST

2023, Science of the Total Environment (904)

Carrie E Givens, Dana W. Kolpin, Laura E. Hubbard, Shannon M. Meppelink, David M. Cwiertny, Darrin A. Thompson, Rachael F. Lane, Michaelah C. Wilson

Released September 04, 2023 07:18 EST

2023, Enviornmental Monitoring and Assessment (195)

Jennifer M. Bayer, Rebecca A Scully, Erin K Dlabola, Jennifer L Courtwright, Christine L Hirsch, David P Hockman-Wert, Scott W. Miller, Brett B. Roper, W Carl Saunders, Marcia N Snyder

Released September 04, 2023 07:15 EST

2023, Nature Sustainability

David D. Briske, Steven R. Archer, Emily Burchfield, William Burnidge, Justin D. Derner, Hannah Gosnell, Jerry Hatfield, Clare E. Kazanski, Mona Khalil, Tyler J. Lark, Pamela L. Nagler, Osvaldo E. Sala, Nathan F. Sayre, Kimberly R. Stackhouse-Lawson

Released September 04, 2023 07:07 EST

2023, Estuaries and Coasts

Laura Feher, Michael Osland, Darren Johnson, James Grace, Glenn R. Guntenspergen, David R. Stewart, Carlos A. Coronado-Molina, Fred H. Sklar

Released September 04, 2023 07:07 EST

2023, Wetlands Ecology and Management

Spenser L. Widin, Wesley A. Bickford, Kurt P. Kowalski

Released September 04, 2023 07:01 EST

2023, Pacific Science (77) 87-101

Valentina Alvarez, Samuel R Fisher, Anthony J. Barley, Kevin Donmoyer, Mozes P. K. Blom, Robert C. Thomson, Robert N. Fisher