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Publications recently added to the Pubs Warehouse

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Managing water resources on Long Island, New York, with integrated, multidisciplinary science

Released September 24, 2021 14:10 EST

2021, Fact Sheet 2021-3044

Robert F. Breault, John P. Masterson, Christopher E. Schubert, Liv M. Herdman

Nutrients, harmful algal blooms, and synthetic chemicals like per- and polyfluoroalkyl substances (PFAS) and 1,4-dioxane threaten Long Island’s water resources by affecting the quality of drinking water and ecologically sensitive habitats that support the diverse wildlife throughout the island. Understanding the occurrence, fate, and transport of these potentially harmful chemicals is critical to protect these vital resources. The U.S. Geological Survey (USGS) is collecting and analyzing data to support informed water-resource management decisions. This fact sheet introduces ongoing efforts and future areas of study aimed to help water professionals develop a comprehensive science strategy to address contamination of the Long Island aquifer system, the sole source of drinking water for nearly 3 million people. These studies include surface and groundwater collection and groundwater flow modeling. Funding for the data collection has been provided by the USGS, New York State Department of Environmental Conservation, New York City Department of Environmental Protection, Suffolk County Water Authority, Nassau County Department of Public Works, State and local agencies, and Tribal and Federal partners. Without the foresight and long-term commitment of these funding partners, evaluating sustainability and planning for future water needs would not be possible.

Evaluating the state-of-the-art in remote volcanic eruption characterization Part I: Raikoke volcano, Kuril Islands

Released September 24, 2021 10:28 EST

2021, Journal of Volcanology and Geothermal Research (419) 1-14

Kathleen McKee, Cassandra Marie Smith, Kevin Reath, Eveanjelene Snee, Sean Maher, Robin S. Matoza, Simon A Carn, Larry G. Mastin, Kyle R. Anderson, David Damby, Diana Roman, Artem Degterev, Alexander Rybin, Marina Chibisova, Jelle D. Assink, Rodrigo de Negri Levia, Anna Perttu

Raikoke, a small, unmonitored volcano in the Kuril Islands, erupted in June 2019. We integrate data from satellites (including Sentinel-2, TROPOMI, MODIS, Himawari-8), the International Monitoring System (IMS) infrasound network, and global lightning detection network (GLD360) with information from local authorities and social media to retrospectively characterize the eruptive sequence and improve understanding of the pre-, syn- and post- eruptive behavior. We observe six infrasound pulses beginning on 21 June at 17:49:55 UTC as well as the main Plinian phase on 21 June at 22:29 UTC. Each pulse is tracked in space and time using lightning and satellite imagery as the plumes drift eastward. Post-eruption visible satellite imagery shows expansion of the island's surface area, an increase in crater size, and a possibly-linked algal bloom south of the island. We use thermal satellite imagery and plume modeling to estimate plume height at 10–12 km asl and 1.5–2 × 106 kg/s mass eruption rate. Remote infrasound data provide insight into syn-eruptive changes in eruption intensity. Our analysis illustrates the value of interdisciplinary analyses of remote data to illuminate eruptive processes. However, our inability to identify deformation, pre-eruptive outgassing, and thermal signals, which may reflect the relatively short duration (~12 h) of the eruption and minimal land area around the volcano and/or the character of closed-system eruptions, highlights current limitations in the application of remote sensing for eruption detection and characterization.

Methods for estimating regional skewness of annual peak flows in parts of eastern New York and Pennsylvania, based on data through water year 2013

Released September 24, 2021 09:50 EST

2021, Scientific Investigations Report 2021-5015

Andrea G. Veilleux, Daniel M. Wagner

Bulletin 17C (B17C) recommends fitting the log-Pearson Type III (LP−III) distribution to a series of annual peak flows at a streamgage by using the method of moments. The third moment, the skewness coefficient (or skew), is important because the magnitudes of annual exceedance probability (AEP) flows estimated by using the LP–III distribution are affected by the skew; interest is focused on the right-hand tail of the distribution, which represents the larger annual peak flows that correspond to small AEPs. For streamgages having modest record lengths, the skew is sensitive to extreme events like large floods, which cause a sample to be highly asymmetrical or “skewed.” For this reason, B17C recommends using a weighted-average skew computed from the skew of the annual peak flows for a given streamgage and a regional skew. This report presents an estimate of regional skew for a study area encompassing parts of eastern New York and Pennsylvania. A total of 232 candidate U.S. Geological Survey streamgages that were unaffected by extensive regulation, diversion, urbanization, or channelization were considered for use in the skew analysis; after screening for redundancy and pseudo record length (PRL) of at least 36 years, 183 streamgages were selected for use in the study.

Flood frequencies for candidate streamgages were analyzed by employing the expected moments algorithm, which extends the method of moments so that it can accommodate interval, censored, and historical/paleo flow data, as well as the multiple Grubbs-Beck test to identify potentially influential low floods in the data series. Bayesian weighted least squares/Bayesian generalized least squares regression was used to develop a regional skew model for the study area that would incorporate possible variables (basin characteristics) to explain the variation in skew in the study area. Ten basin characteristics were considered as possible explanatory variables; however, none produced a pseudo coefficient of determination greater than 1 percent; as a result, these characteristics did not help to explain the variation in skew in the study area. Therefore, a constant model that had a regional skew coefficient of 0.32 and an average variance of prediction at a new streamgage (AVPnew, which corresponds to the mean square error [MSE] of 0.11) was selected. The AVPnew corresponds to an effective record length of 68 years, a marked improvement over the Bulletin 17B national skew map, whose reported MSE of 0.302 indicated a corresponding effective record length of only 17 years.

Multidisciplinary constraints on magma compressibility, the pre-eruptive exsolved volatile fraction, and the H2O/CO2 molar ratio for the 2006 Augustine eruption, Alaska

Released September 24, 2021 09:41 EST

2021, Geochemistry, Geophysics, Geosystems (G-Cubed) (22) 1-24

Valerie K. Wasser, Taryn M. Lopez, Kyle R. Anderson, Pavel E. Izbekov, Jeffrey T. Freymueller

Geodetically modeled reservoir volume changes during volcanic eruptions are commonly much smaller than the observed eruptive volumes. This discrepancy is thought to be partially due to the compressibility of magma, which is largely controlled by the presence of exsolved volatiles. The 2006 eruption of Augustine Volcano, Alaska, produced an eruptive volume that was ∼3 times larger than the geodetically estimated syn-eruptive subsurface volume change. In this study, we use a multistep methodology that combines constraints from geodetic, volcanic gas, geologic, and petrologic data together with equations relating physical processes to observable parameters. We apply a Monte Carlo approach to quantify uncertainties. Ultimately, we solve for the exsolved volatile volume fraction and the magma compressibility. We estimate Augustine's 2006 pre-eruptive exsolved volatile phase to be ∼5.5 vol% of the magma at storage depths, yielding a bulk magma compressibility of ∼3.8 × 10−10 Pa−1. We develop a novel approach to estimate the H2O/CO2 ratio of the syn-eruptive gas emissions in the absence of direct H2O emission measurements which are hard to obtain due to the high background levels in ambient air. We find a best-fit H2O/CO2 molar ratio of 29. We also investigate the effects of applying different equations of state to our model. We find that the Ideal Gas Law might be used as a first approximation due to its simplicity; however, it overestimates volatile density and compressibility significantly at storage depths. This project capitalizes on the insights that can be gained by integrating multidisciplinary data with models of physical processes.

Historical streamflow and stage data compilation for the Lower Columbia River, Pacific Northwest

Released September 24, 2021 07:39 EST

2021, Open-File Report 2020-1138

Carrie L. Boudreau, Marc A. Stewart, Adam J. Stonewall

The U.S. Geological Survey mined data from a variety of national and state agencies including USGS, Oregon Water Resources Department, National Oceanic and Atmospheric Administration, Washington Department of Ecology, Pacific Northwest National Laboratory, Portland State University, and U.S. Army Corps of Engineers. A comprehensive dataset of streamflow, stage, and tidal elevations for the Lower Columbia River basin was compiled. Data were compiled from gaging stations in Oregon and Washington along the Columbia River from Astoria to The Dalles and along the Willamette River from Salem to Portland. Tidal gages along the Washington, Oregon, and California coasts were also compiled. Seasonal maximum values were calculated for both streamflow and stage for the winter (November–March) and spring (April–July) flow seasons, as well as for the full water year when underlying data were available. The aggregated datasets are available at

Discharge and dissolved-solids characteristics of Blacks Fork above Smiths Fork, Wyoming, April 2018 through September 2019

Released September 23, 2021 22:04 EST

2021, Scientific Investigations Report 2021-5095

Cheryl A. Eddy-Miller, Jerrod D. Wheeler, Ruth M. Law, Shaun W. Moran

The Colorado River Basin Salinity Control Forum was formed in 1973 to coordinate salinity control efforts among the States in the Colorado River Basin, including Wyoming. The Colorado River Salinity Control Act of 1974 (Public Law 93–320) authorized “the construction, operation, and maintenance of certain works in the Colorado River Basin to control the salinity of water delivered to users in the United States and Mexico.” Water-quality standards for salinity in the lower Colorado River Basin were adopted in 1975. To help meet these standards, the Bureau of Reclamation, Natural Resource Conservation Service, and States within the Colorado River Basin have implemented salinity control projects that focus on reducing salt loading associated with irrigated agriculture by improving water delivery systems and water management practices. The term salinity is synonymous with dissolved solids in this report.

The Bureau of Reclamation, in conjunction with the Colorado River Basin Salinity Control Forum, was interested in determining the contribution of dissolved solids from Blacks Fork above Smiths Fork to the Colorado River and initiated a study of Blacks Fork above Smiths Fork in 2018. In early 2018, the U.S. Geological Survey installed a streamgage at the most downstream location on the Blacks Fork, upstream from the convergence with Smiths Fork, to characterize the stream. The Blacks Fork above Smiths Fork, near Lyman, Wyoming, streamgage (U.S. Geological Survey identifier 09219200) was operated from April 4, 2018, through September 30, 2019, collecting continuous stream stage and specific-conductance data, from which continuous discharge, dissolved-solids concentrations, and dissolved-solids loads were calculated. Seven sites were selected on Blacks Fork and a tributary to describe a snapshot of the discharge and dissolved-solids characteristics. These sites were sampled during July, August, and September 2018 and June, July, August, and September 2019 report.

Discharge at the Blacks Fork above Smiths Fork, near Lyman, Wyo., streamgage (09219200) from April through September in 2018 was lower and less variable than during the same period in 2019. The mean daily (mean of the daily means) discharge during those 6 months in 2018 (15.1 cubic feet per second [ft3/s]) was about one-tenth of the discharge during the same period in 2019 (152 ft3/s). The cumulative monthly discharge during April through September in 2018 was 5,360 acre-feet, about one-tenth of the discharge during the same period in 2019 which was 54,700 acre-feet. Similar differences in discharge between the 2018 and 2019 periods also are noted at other Blacks Fork streamgages in the area.

Continuous specific conductance data and the statistical relation between specific conductance and dissolved-solids concentrations were used to calculate the daily mean dissolved-solids concentrations. Dissolved solids often have an inverse relation with discharge because higher discharges typically have a diluting effect that lowers the dissolved-solids concentrations. In general, when discharges at the Blacks Fork above Smiths Fork streamgage (09219200) are higher, dissolved-solids concentrations are generally lower. However, the high dissolved-solids concentrations that are measured during high discharges indicate that the system has natural variability and the dissolved-solids concentrations are determined by more factors than just discharge. The mean daily dissolved-solids concentration during April through September 2018 was 1,630 milligrams per liter and during the same period in 2019 was 1,100 milligrams per liter.

Dissolved-solids loads were calculated as the product of the discharge and dissolved-solids concentration. The daily mean dissolved-solids loads during 2018 were typically lower than during 2019. This result is primarily because the discharge was much lower in 2018 than in 2019. Therefore, although the daily mean dissolved-solids concentrations tended to be higher in 2018, the substantially higher discharges in 2019 had more of an effect on the dissolved-solids loads than the dissolved-solids concentrations.

The cumulative dissolved-solids load at the Blacks Fork above Smiths Fork, near Lyman, Wyo., streamgage (09219200) during the 18-month study was 81,200 tons, with a mean daily load of 149 tons per day. During the 6-month period from April through September 2018, the cumulative dissolved-solids load at the streamgage was estimated to be 8,740 tons and, during the same 6 months in 2019, the cumulative dissolved-solids load was estimated to be 60,900 tons. During the fall and winter between the two periods, the cumulative dissolved-solids load was 11,600 tons.

Discharge and dissolved-solids concentrations from samples collected during the synoptic sampling events were highly variable among most sites during most synoptic sampling events and also highly variable at most sites among different sampling events. The two sites upstream from the tributary input from Threemile Creek had lower dissolved-solids concentrations than sites including and downstream from the tributary. Sites including and downstream from the tributary had similar values and variability of dissolved-solids loads, with the exception of the farthest downstream site at the Blacks Fork above Smiths Fork, near Lyman, Wyo., streamgage (09219200) that tended to have larger dissolved-solids loads and higher variability among synoptic sampling events.

Hydrogeologic framework of the Big Lost River Basin, south-central Idaho, chap. A of Zinsser, L.M., ed., Characterization of water resources in the Big Lost River Basin, south-central Idaho

Released September 23, 2021 13:00 EST

2021, Scientific Investigations Report 2021-5078-A

Lauren M. Zinsser

Surface-water and groundwater resources in the Big Lost River Basin of south-central Idaho are extensively interconnected; this interchange affects and is affected by water-resource management for irrigated agriculture and other uses in the basin. Concerns from water users regarding declining groundwater levels, declining streamflows, and drought helped motivate an updated evaluation of water resources in the Big Lost River Basin. The hydrogeologic framework presented in this report provides a conceptual basis for understanding groundwater resources in the Big Lost River Basin and comprises three major parts: (1) conceptual description of four hydrogeologic units, (2) development of a three-dimensional hydrogeologic framework model representing the spatial distribution of the hydrogeologic units, and (3) a description of groundwater occurrence and movement. This hydrogeologic framework represents the first of three planned reports describing water resources in the Big Lost River Basin; subsequent reports are intended to present a groundwater budget for the basin and to describe the results of a series of events measuring gains to and losses from streamflow in the Big Lost River. This report was prepared by the U.S. Geological Survey in cooperation with the Idaho Department of Water Resources.

The Big Lost River Basin has four hydrogeologic units. First, the Quaternary unconsolidated sediments unit comprises the basin-fill alluvial aquifer and generally is used within 250 feet of the land surface. The Quaternary unconsolidated sediments unit is spatially heterogeneous, with locally confining conditions in some areas, and is the most heavily used hydrogeologic unit in the basin. Second, the Paleozoic sedimentary rocks unit, composed primarily of carbonates with some siliciclastic rocks, represents the major bedrock aquifer and contributes subsurface recharge at the margins of the alluvial aquifer. Third, the Tertiary volcanic rocks unit, composed primarily of andesite and dacite with lesser tuff, is locally important to water production, particularly in faulted and fractured zones. The Paleozoic sedimentary rocks hydrogeologic unit occurs at the valley margins and underlies tributaries throughout the basin, whereas the Tertiary volcanic rocks hydrogeologic unit primarily occurs in uplands in the western one-half of the basin. Fourth, the Quaternary basalt rocks unit consists of multiple basalt flows that are interbedded with the Quaternary unconsolidated sediments unit in the southern end of the Big Lost River Basin and contains at least three water-bearing zones. Insights gained from this updated hydrogeologic framework will help inform current water-resource management in the Big Lost River Basin.

Earth Resources Observation and Science Center—Keeping watch over Earth's resources

Released September 23, 2021 11:43 EST

2021, Fact Sheet 2021-3052

U.S. Geological Survey

The Earth Resources Observation and Science (EROS) Center is the largest facility of its kind within the U.S. Geological Survey. As both a science and data center, EROS serves a unique and critical role in shaping our understanding of a changing planet.

EROS opened its doors in 1973 as a receiving station, data archive, and data distribution hub for the USGS Landsat series of Earth observing satellites. In the nearly five decades since, EROS has grown into a globally recognized leader in land change science.

Origin of unconsolidated Quaternary deposits at Harriet Point near Redoubt Volcano, Alaska

Released September 23, 2021 09:25 EST

2021, Scientific Investigations Report 2021-5071

Christopher F. Waythomas

Unconsolidated boulder-rich diamicton units exposed in sea cliffs at Harriet Point southeast of Redoubt Volcano were evaluated to better understand their provenance relative to the late Quaternary eruptive history of the volcano. A previous study concluded that deposits at Harriet Point were emplaced by a large volcanic landslide originating on the southeast flank of Redoubt Volcano (Begét and Nye, 1994). Field-based analysis of the stratigraphy and sedimentology of the Harriet Point deposits and numerical simulations of the volcanic landslide area of inundation indicate that none of the deposits are volcanogenic. All of the unconsolidated boulder-rich diamicton units at Harriet Point are glacial in origin and can be reconciled using the presently available model for late Quaternary glaciation of Cook Inlet.

Economic assessment of surface water in the Harney Basin, Oregon

Released September 23, 2021 09:15 EST

2021, Open-File Report 2021-1087

Lucas S. Bair, Matthew Flyr, Christopher Huber

Executive Summary

The Harney Basin is a closed river basin in southeastern Oregon. Surface water in the basin is used for a variety of social, economic, and ecological benefits. While some surface water uses compete with one another, others are complementary or jointly produce multiple beneficial outcomes. The objective of this study is to conduct an economic assessment of surface water in the basin as it relates to wet meadow pasture production and outdoor recreation. Given the complex interactions between surface water management on public and private land and the various goods and services that are derived from adequate water resources, an economic assessment of surface water management can be used to assist future decision making in the basin.

Survival and abundance of polar bears in Alaska’s Beaufort Sea, 2001–2016

Released September 23, 2021 08:38 EST

2021, Ecology and Evolution

Jeffrey F. Bromaghin, David C. Douglas, George M. Durner, Kristin S. Simac, Todd C. Atwood

The Arctic Ocean is undergoing rapid transformation toward a seasonally ice-free ecosystem. As ice-adapted apex predators, polar bears (Ursus maritimus) are challenged to cope with ongoing habitat degradation and changes in their prey base driven by food-web response to climate warming. Knowledge of polar bear response to environmental change is necessary to understand ecosystem dynamics and inform conservation decisions. In the southern Beaufort Sea (SBS) of Alaska and western Canada, sea ice extent has declined since satellite observations began in 1979 and available evidence suggests that the carrying capacity of the SBS for polar bears has trended lower for nearly two decades. In this study, we investigated the population dynamics of polar bears in Alaska's SBS from 2001 to 2016 using a multistate Cormack–Jolly–Seber mark–recapture model. States were defined as geographic regions, and we used location data from mark–recapture observations and satellite-telemetered bears to model transitions between states and thereby explain heterogeneity in recapture probabilities. Our results corroborate prior findings that the SBS subpopulation experienced low survival from 2003 to 2006. Survival improved modestly from 2006 to 2008 and afterward rebounded to comparatively high levels for the remainder of the study, except in 2012. Abundance moved in concert with survival throughout the study period, declining substantially from 2003 and 2006 and afterward fluctuating with lower variation around an average of 565 bears (95% Bayesian credible interval [340, 920]) through 2015. Even though abundance was comparatively stable and without sustained trend from 2006 to 2015, polar bears in the Alaska SBS were less abundant over that period than at any time since passage of the U.S. Marine Mammal Protection Act. The potential for recovery is likely limited by the degree of habitat degradation the subpopulation has experienced, and future reductions in carrying capacity are expected given current projections for continued climate warming.

Evidence for humans in North America during the Last Glacial Maximum

Released September 23, 2021 08:19 EST

2021, Science 1528-1531

Matthew R. Bennett, David Bustos, Jeffrey S. Pigati, Kathleen B. Springer, Thomas. M. Urban, Vance T. Holliday, Sally C. Reynolds, Marcin Budka, Jeffrey S. Honke, Adam M. Hudson, Brendan Fenerty, Clare Connelly, Patrick J. Martinez, Vincent L. Santucci, Daniel Odess

Archaeologists and researchers in allied fields have long sought to understand human colonization of North America. When, how, and from where did people migrate, and what were the consequences of their arrival for the established fauna and landscape are enduring questions. Here, we present evidence from excavated surfaces of in situ human footprints from White Sands National Park (New Mexico, USA), where multiple human footprints are stratigraphically constrained and bracketed by seed layers that yield calibrated ages between ~23 and 21 ka. These findings confirm the presence of humans in North America during the Last Glacial Maximum, adding evidence to the antiquity of human colonization of the Americas, and provide a temporal range extension for the co-existence of early inhabitants and Pleistocene megafauna.

Drought resistance and resilience: The role of soil moisture–plant interactions and legacies in a dryland ecosystem

Released September 22, 2021 07:18 EST

2021, Journal of Ecology (109) 3280-3294

Dave Hoover, Alix A. Pfennigwerth, Michael C. Duniway

  1. In many regions of the world, climate change is projected to reduce water availability through changes in the hydrological cycle, including more frequent and intense droughts, as well as seasonal shifts in precipitation. In water-limited ecosystems, such as drylands, lower soil water availability may exceed the adaptive capacity of many organisms, leading to cascading ecological effects during (concurrent effects) and after drought (legacy effects). The magnitude and duration of concurrent and legacy effects depends on drought intensity, duration and timing as well as the resistance and resilience of the ecosystem.
  2. Here, we investigated the effects of drought seasonality and plant community composition on two dominant perennial grasses, Achnatherum hymenoides (C3 photosynthesis) and Pleuraphis jamesii (C4 photosynthesis), in a dryland ecosystem. The experiment consisted of three precipitation treatments: control (ambient precipitation), cool-season drought (−66% ambient precipitation November–April) and warm-season drought (−66% ambient precipitation May–October), applied in two plant communities (perennial grasses with or without a large shrub, Ephedra viridis) over a 3-year period. We examined the concurrent and legacy effects of seasonal drought on soil moisture, phenology and biomass.
  3. Drought treatments had strong concurrent and legacy effects on soil moisture, which impacted the phenology and biomass of the two grasses. Drought reduced growing season length by delaying green-up (cool-season drought) or advancing senescence (warm-season drought) and reduced biomass for both species. Biomass and phenology legacy effects from drought emerged in the second and third years of the experiment. While we observed differential sensitivity to drought legacies between the two grasses, we found limited evidence that shrub presence had interactive effects with the drought treatment.
  4. Synthesis. The results from this study highlight how abiotic and biotic legacies can develop and influence a community's resistance and resilience to subsequent droughts. When the frequency of repeated extreme events, such as recurring seasonal droughts, exceeds the capacity of organisms or ecosystems to recover (i.e. resilience), persistent drought legacies can reduce the resistance to subsequent drought events. Overall, these results highlight how drought legacies are a product of ecological resistance and resilience to past drought and can influence ecosystem vulnerability to future droughts.

Geochemical and mineralogical properties of Boquillas Shale geochemical reference material ShBOQ-1

Released September 20, 2021 18:15 EST

2021, Fact Sheet 2021-3048

Justin E. Birdwell, Stephen A. Wilson

The ShBOQ-1 geochemical reference material is relevant to studies of the organic geochemistry and mineralogy of petroleum source rocks containing high concentrations of carbonate minerals and organic sulfur-rich, oil-prone marine organic matter. ShBOQ-1 is geochemically and mineralogically similar to the lower part of the Upper Cretaceous Eagle Ford Shale.

Development of regression equations for the estimation of the magnitude and frequency of floods at rural, unregulated gaged and ungaged streams in Puerto Rico through water year 2017

Released September 20, 2021 09:49 EST

2021, Scientific Investigations Report 2021-5062

Patrick J. Ryan, Anthony J. Gotvald, Cody L. Hazelbaker, Andrea G. Veilleux, Daniel M. Wagner

The methods of computation and estimates of the magnitude of flood flows were updated for the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent chance exceedance levels for 91 streamgages on the main island of Puerto Rico by using annual peak-flow data through 2017. Since the previous flood frequency study in 1994, the U.S. Geological Survey has collected additional peak flows at additional streamgages, and Puerto Rico has experienced numerous flood events. This updated study was performed using longer annual peak-flow datasets from more stations to provide more representative equations to predict flood flows. Screening criteria for these streamgages included 10 or more years of annual peak-flow data, unregulated flow, and less than 10 percent impervious drainage area.

The magnitude and frequency of floods at selected streamgages in Puerto Rico were estimated using updated methods outlined in Bulletin 17C. The new procedures include a regional skew analysis that incorporates Bayesian regression techniques, the Expected Moments Algorithm to better represent missing record and estimate parameters of the log-Pearson Type III distribution, and the Multiple Grubbs-Beck test for low outlier detection.

Regional regression equations were developed to estimate peak-flow statistics at ungaged locations by using selected basin and climatic characteristics as explanatory variables. These variables were determined from digital spatial datasets and geographic information systems by using the most recent data available. Ordinary least-squares regression techniques were used to filter the basin characteristics and determine two separate regions, region 1 (west) and region 2 (east), based on residuals. A generalized least-squares procedure was used to account for cross-correlation of sites and develop the final set of equations that have drainage area as the only explanatory variable. The average standard errors of prediction ranged from 18.7 to 46.7 percent in region 1 and 33.4 to 57.6 percent in region 2 for all annual exceedance probabilities (AEPs) examined. The updated statistics showed a greater accuracy of prediction when compared to those from the previous study using drainage area as the only explanatory variable for all AEPs examined in region 1 and the 0.01 and 0.002 AEP flows for region 2. When compared to equations developed in the previous study that have drainage area, mean annual rainfall, and (or) depth-to-rock as explanatory variables, the updated statistics show a greater accuracy of prediction in region 1 at AEP flows of 0.02 and lower (that is, higher flows). Those developed for region 2 do not show a greater accuracy of prediction for any AEP flows when compared to the equations having multiple explanatory variables in the previous study.

The calculated regression equations, basin characteristics, and at-site statistics will be incorporated into the U.S. Geological Survey web application, StreamStats ( This application allows users to select a location on a stream, whether gaged or ungaged, to obtain estimates of basin characteristics and flow statistics.

A comparison of methods for the long-term harness-based attachment of radio-transmitters to juvenile Japanese quail (Coturnix japonica)

Released September 20, 2021 07:50 EST

2021, Animal Biotelemetry (9)

Evan J Buck, Jeffery D Sullivan, Cody M. Kent, Jennifer M. Mullinax, Diann Prosser


While the period from fledging through first breeding for waterbird species such as terns (e.g., genus Sterna, Sternula) is of great interest to researchers and conservationists, this period remains understudied due in large part to the difficulty of marking growing juveniles with radio transmitters that remain attached for extended periods.


In an effort to facilitate such research, we examined the impact of various combinations of harness types (backpack, leg-loop, and 3D-printed harnesses), harness materials (Automotive ribbon, Elastic cord, and PFTE ribbon), and transmitter types (center-weighted and rear-weighted) on a surrogate for juvenile terns, 28-day-old Japanese quail (Coturnix japonica; selected due to similarities in adult mass and downy feathering of juveniles), in a 30-day experiment. We monitored for abrasion at points of contact and tag gap issues via daily exams while also recording mass and wing cord as indices of growth. This study was designed to serve as an initial examination of the impacts of marking on the growth and development of young birds and does not account for any impacts of tags on movement or behavior.


While we found that treatment (the specific combination of the transmitter type, harness type, and harness material) had no impact on bird growth relative to unmarked control birds (P ≥ 0.05), we did observe differences in abrasion and tag gap between treatments (P ≤ 0.05). Our results suggest that leg-loop harnesses constructed from elastic cord and backpack harnesses from PFTE ribbon are suitable options for long-term attachment to growing juveniles. Conversely, we found that automotive ribbon led to extensive abrasion with these small-bodied birds, and that elastic cord induced blisters when used to make a backpack harness.


While these results indicate that long-term tagging of juvenile birds is possible with limited impacts on growth, this work does not preclude the need for small-scale studies with individual species. Instead, we hope this provides an informed starting point for further exploration of this topic.

Development of a screening tool to examine lake and reservoir susceptibility to eutrophication in selected watersheds of the eastern and southeastern United States

Released September 20, 2021 06:57 EST

2021, Scientific Investigations Report 2021-5075

W. Reed Green, Anne B. Hoos, Alan E. Wilson, Elizabeth N. Heal

This report describes a new screening tool to examine lake and reservoir susceptibility to eutrophication in selected watersheds of the eastern and southeastern United States using estimated nutrient loading and flushing rates with measures of waterbody morphometry. To that end, the report documents the compiled data and methods (R-script) used to categorize waterbodies by Carlson’s Trophic State Index. Assessments were completed for 232 lakes and reservoirs having a surface area greater than or equal to 0.1 square kilometer in watersheds that drain to the Atlantic and eastern Gulf of Mexico coasts of the United States and in watersheds within the Tennessee River Basin. Waterbodies were categorized by type—natural lakes, headwater reservoirs, and downstream reservoirs—and were assessed independently. Recursive partitioning and the model-based boosting routine were used to create four-node regression trees to group waterbodies into five endpoints from low-to-high measures of Secchi depth, and concentrations of chlorophyll a and microcystin according to shared nutrient loading, flushing rate, and morphometric characteristics. Trophic state designations were assigned based on the average value within each of the five endpoints. An application (procedure) is provided using the tool to examine the susceptibility of a given waterbody of interest to eutrophication. Results of this study can aid water-resource managers in prioritizing lake and reservoir protection and restoration efforts based on the susceptibility of these waterbodies to eutrophication relative to nutrient loading, flushing rate, and morphometric characteristics.

Estimates of public-supply, domestic, and irrigation water withdrawal, use, and trends in the Upper Rio Grande Basin, 1985 to 2015

Released September 17, 2021 12:00 EST

2021, Scientific Investigations Report 2021-5036

Tamara I. Ivahnenko, Allison K. Flickinger, Amy E. Galanter, Kyle R. Douglas-Mankin, Diana E. Pedraza, Gabriel B. Senay

The Rio Grande flows approximately 670 miles from its headwaters in the San Juan Mountains of south-central Colorado to Fort Quitman, Texas, draining the Upper Rio Grande Basin (URGB) study area of 32,000 square miles that includes parts of Colorado, New Mexico, and Texas. Parts of the basin extend into the United Mexican States (hereafter “Mexico”), where the Rio Grande forms the international boundary between Texas and the State of Chihuahua, Mexico. The URGB was chosen as a focus area study (FAS) for the U.S. Geological Survey (USGS) National Water Census (NWC) as part of the WaterSMART initiative. The objective of the USGS NWC under WaterSMART is to focus on the technical aspects of providing information and tools to stakeholders so that they can make informed decisions on water availability.

This report contains water-use withdrawal estimates of groundwater and surface water for public-supply, self-supplied domestic, and irrigation water use for years 1985–2015 at 5-year intervals for the 22 drainage basins at the subbasin 8-digit hydrologic unit code (HUC-8) level. Data for additional categories of self-supplied industrial, mining, livestock, aquaculture, thermoelectric, and hydroelectric water use are provided in the accompanying data release to illustrate total withdrawals for the URGB. The additional category data are provided in this report only for the year 2015. Deliveries of water from public-supply systems to domestic users are included and are the only water-delivery data presented in this report. Consumptive use for irrigation is reported for all HUC-8 subbasins for 2015 and for select HUC-8s in the other years beginning in 1985 (the irrigation category includes irrigation for both crop and golf). Water transported outside of the URGB (interbasin transfers) is not included as part of the withdrawals and are not accounted for in any category of use within the URGB.

Estimated total withdrawals for all the water-use categories (including hydroelectric) in 2015 as reported in the USGS compilations in the URGB were 3,152.10 million gallons per day (Mgal/d). Surface water was the dominant source of water used in the URGB, providing about 71 percent of total withdrawals. Nearly all withdrawals were from freshwater sources; there was a small amount of saline groundwater that was used for public supply and self-supplied industrial, which were all reported in Texas. The proportions of total 2015 withdrawals from States in the URGB are 46 percent each in Colorado and New Mexico and 8 percent in Texas. A comparison of 2015 water withdrawals for the URGB—for the categories of public supply, self-supplied domestic, self-supplied industrial, thermoelectric, irrigation, livestock, mining, aquaculture, and hydroelectric—showed that irrigation is the dominant water use, at 74 percent of total withdrawals. Other water-use categories in the URGB that use about 1 percent or greater of the total water use by volume are public supply (9 percent) and self-supplied domestic and aquaculture (each about 1 percent). This report focuses on the higher volume, consumptively used categories of public supply, self-supplied domestic, and irrigation. A discussion on basin population provides context for the categories of public-supply and self-supplied domestic water use.

The population in the part of the basin in the United States grew from 1.36 to 2.26 million people between 1985 and 2015. With the city of Ciudad Juarez, Chihuahua, Mexico, included, the total population of the URGB grew from an estimated 2.01 to 3.66 million people between 1985 and 2015. The largest concentrations of population are in New Mexico, Texas, and Chihuahua, with 98 percent of the total number of people in the basin in 1985 and 99 percent of the total in 2015 residing in these states. Albuquerque, El Paso, and Ciudad Juarez are the largest cities in the basin.

Total withdrawals for public supply in the URGB averaged 277 Mgal/d from 1985 to 2015. About 60 percent of the URGB total public-supply withdrawals occurred in New Mexico, which averaged 170 Mgal/d. Groundwater provided 92 and 70 percent of the total withdrawals for public supply in 1985 and 2015, respectively. Deliveries to domestic users from public suppliers are reported for all drainage basins and years, and account for part of the total public-supply withdrawals. In the URGB, domestic deliveries from public suppliers increased from 1985 to 1995; since 2005, domestic deliveries from public supply have declined. The total populations served by public suppliers in the URGB increased by 90 percent from 1985 to 2015. In the URGB, more people were served by public-supply systems than were self-supplied, and the percentage of people on public-supply systems ranged from 81 to 92 percent from 1985 to 2015. Total domestic withdrawals in the URGB (deliveries plus self-supply withdrawals) ranged from 177.49 to 234.83 Mgal/d and peaked in 2005. Domestic use decreased from 2005 to 2010 by 17 percent and remained less than 200 Mgal/d in 2015. The per-capita daily use for the entire URGB fluctuated between the reporting years, but overall, domestic per-capita use across the basin has declined 46 percent from 145 gallons per capita daily (gpcd) in 1985 to 79 gpcd in 2015.

Total irrigation withdrawals in the URGB had a mean value of 2,767.66 Mgal/d from 1985 to 2015 and withdrawals peaked in 1995 at 3,416.84 Mgal/d. Over the 30-year period, irrigation source water in the URGB has ranged from 69 to 84 percent surface water, and the most surface water diverted in the basin for irrigation was in 1995. Groundwater withdrawals for irrigation have fluctuated but overall decreased by 13 percent between 2005 and 2015. Slightly more than one-half of total irrigation withdrawals within the URGB occurred in Colorado, with a mean of 57 percent from 1985 to 2015. From the peak of water withdrawals in 1995 to the conclusion of this study in 2015, total irrigation withdrawals across the study area decreased by 32 percent.

The total number of irrigated lands in the URGB from 1985 to 2015 had a mean of about 800 thousand acres, and more irrigated lands were consistently located in the headwaters of the URGB in the San Luis Valley, Colorado than the remainder of the study basin. In the 30-year period, Colorado had a mean of 68 percent of total irrigated lands whereas irrigated acres in New Mexico had a mean of 26 percent and the remaining 7 percent were in Texas. Since 2000, the number of irrigated acres in the URGB has fluctuated, but overall has decreased by 12 percent.

More land was irrigated with surface systems (surface irrigation includes flood, furrow, and gated pipe systems, hereafter collectively termed “surface”) in the URGB than with other irrigation system types. Across the 30-year period, from 62 to 88 percent of total irrigated lands had surface-system irrigation, and surface systems covered a mean of 69 percent of the URGB’s acres. Microirrigation systems, predominantly in New Mexico and Texas, compose 0.2 percent or less of the irrigated acres in the basin and were first reported in 1995. From 1985 to 2015, the surface systems decreased in the basin by about 38 percent, and the number of acres of sprinkler and microirrigation systems increased. Acres irrigated by sprinkler systems (predominately center pivot systems) have increased 179 percent from about 99 thousand acres in 1985 to 275 thousand acres in 2015. In this dataset, the number of sprinkler acres surpassed the number of surface irrigated acres in 2000. Within the San Luis Valley in Colorado, the acreage of surface irrigation has decreased, and sprinkler irrigation has increased over the 30-year period. In the New Mexico part of the URGB, surface irrigation is reported as the dominant system type, where irrigation by surface systems accounts for 97–98 percent of how water is provided to crops. As in New Mexico, crops in Texas are irrigated primarily by surface systems.

The mean of the mean simulated actual evapotranspiration (ETa) for crops in 2015 across the basin was highest for durum wheat at an estimated 36.00 inches per year (in/yr), and lowest for vegetables at an estimated 19.48 in/yr. Alfalfa and irrigated grass pastures mean ETa had a mean of 31.4 and 27.58 in/yr, respectively, for the basin. Pecans and peppers, both signature crops in the Rio Grande Basin, each had a mean ETa of 30.67 and 30.38 in/yr of mean. In general, mean ETa values for crops were lower in the HUCs of the Colorado San Luis Valley (13010001, 13010002, 13010003 and 13010004) which are more northerly and at higher elevations. The mean ETa for crops increased in the HUCs that are more southerly and at lower elevations in the basin.

Managed aquifer recharge suitability—Regional screening and case studies in Jordan and Lebanon

Released September 16, 2021 13:59 EST

2021, Open-File Report 2021-1089

Daniel J. Goode, editor(s)

The U.S. Geological Survey, at the request of the U.S. Agency for International Development, led a 5-year regional project to develop and apply methods for water availability and suitability mapping for managed aquifer recharge (MAR) in the Middle East and North Africa region. A regional model of surface runoff for the period from 1984 to 2015 was developed to characterize water availability using remote sensing data on climate, vegetation, and topography in Jordan, Lebanon, and surrounding areas. Surface runoff was accumulated to characterize potential streamflow available for MAR and these data were combined with land surface slope to prepare a regional screening map of MAR suitability, illustrating suitability mapping concepts and methods. The application of the methods is demonstrated by the evaluation of water availability and suitability for potential MAR in study areas in Jordan and Lebanon. Locations suitable for MAR are present in both Jordan and Lebanon, but limitations exist in both countries, related primarily to water availability in Jordan and land areas of suitable terrain in Lebanon. An additional feasibility study including field investigations would likely provide decision makers with essential information for further development of the use of MAR in Jordan, Lebanon, and the region.

Estimating invertebrate response to changes in total nitrogen, total phosphorus, and specific conductance at sites where invertebrate data are unavailable

Released September 16, 2021 09:50 EST

2021, Scientific Investigations Report 2021-5070

Robert E. Zuellig, Daren M. Carlisle

The purpose of this report is to describe a possible approach to estimate changes in invertebrate taxa richness at sites with known water-quality trends but no invertebrate data. In this study, data from 1,322 sites were used to describe invertebrate response to changes in total nitrogen, total phosphorus, or specific conductance, and to estimate changes in invertebrate taxa richness at 259 sites with reported water-quality trends but no invertebrate data. Sites were stratified using propensity score analysis to control for confounding factors (for example, climate, land use, land cover). Generalized linear models were developed to describe changes in invertebrate taxa richness along gradients of total nitrogen, total phosphorus, and specific conductance values. The magnitude and direction of invertebrate response to gradients of water quality varied among parameters and strata, with changes in invertebrate taxa richness per natural log unit change in concentration ranging from –7 to +6. However, estimated changes in invertebrate taxa richness at sites with known water-quality trends were much less and did not exceed three taxa until changes in concentration were greater than 50 percent. Applying this approach provides (1) a first screening to identify where changes in invertebrate taxa richness are likely to occur and (2) the necessary groundwork to improve estimation of invertebrate response to trends in water quality where biological data are lacking.

Kelp forest monitoring at Naval Base Ventura County, San Nicolas Island, California—Fall 2019, sixth annual repor

Released September 15, 2021 13:31 EST

2021, Open-File Report 2021-1081

Michael C. Kenner, Joseph Tomoleoni

The U.S. Geological Survey conducts ecological monitoring of rocky subtidal communities at four permanent sites around San Nicolas Island. The sites—Nav Fac 100, West End, Dutch Harbor, and Daytona 100—were based on ones that had been monitored since 1980 by the U.S. Geological Survey and, in cooperation with the U.S. Navy, were combined or expanded in 2014 for better comparability with monitoring programs conducted at the other California Channel Islands. At the sites, we counted a suite of kelps and invertebrates on benthic band transects, measured bottom cover of algae and sessile invertebrate species in quadrats, and counted and sized fish on swimming transects. Holdfast diameter and number of stipes of giant kelp (Macrocystis pyrifera) were recorded on these transects and size data were collected for urchins, sea stars, and shelled mollusks. Bottom temperatures were recorded at hourly intervals by archival data loggers that were deployed at the sites. Typically, this monitoring work is conducted semi-annually, in fall and spring. Because the spring 2020 trip was cancelled due to the Coronavirus Disease 2019 pandemic, this report focuses primarily on data collected in fall 2019 and makes comparisons with data collected in previous years, beginning in fall 2014.

The sites are distributed around the island and differ in their physical and ecological characteristics. Nav Fac 100, situated on the north side of San Nicolas Island, has a relatively low benthic profile. The invasive brown alga Sargassum horneri was first observed at this site in 2015. West End, to the southwest of the island, also lacks much bottom relief but has more crevice habitat associated with boulders. For almost three decades, West End has been a focal point for the small, but growing, population of southern sea otters (Enhydra lutris nereis) at the island. Dutch Harbor, on the south side, has many high relief rocky reefs and had the greatest fish and non-motile invertebrate densities. Daytona 100, on the southeast side, has moderate relief and has remained a patchwork of kelp and sea urchin dominated areas.

There were no major changes at the sites since spring 2019, but some trends observed during the last few years continued whereas others changed. Red urchins continued a declining trend (observed during the last 4 years) at Daytona 100. The wavy turban snail (Megastraea undosa) began to increase rapidly at Nav Fav 100 in 2015 and has subsequently been increasing at the other sites as well, after more than a decade of very low numbers at all sites. Sea star wasting syndrome, which has devastated multiple species of sea stars along the Pacific coast of North America, affected most species at San Nicolas Island in the year prior to the fall 2014 sampling. Since then, there has been a reduction in the number of bat stars (Patiria miniata), and very few sea stars of other species have been observed. There has been a slight recovery of P. miniata since 2016 but little sign of change in other species. All the sites had a slight decline in the densities of purple urchins following an increase during the previous 2 years. Long-term data are presented to illustrate trends and changes during almost four decades of monitoring this dynamic system.

Evaluation of hydrologic simulation models for fields with subsurface drainage to mitigated wetlands in Barnes, Dickey, and Sargent Counties, North Dakota

Released September 15, 2021 08:47 EST

2021, Scientific Investigations Report 2021-5091

Joel M. Galloway, Wyatt S. Tatge, Spencer L. Wheeling

Proper identification of wetlands, along with a better understanding of the hydrology of mitigated wetlands, is needed to assist with conservation efforts aimed at maintaining the productivity and ecological function (wetland mitigation) of agricultural lands. The U.S. Geological Survey, in cooperation with the U.S. Department of Agriculture Natural Resources Conservation Service, completed a study to evaluate two models for simulating hydrologic conditions in fields with subsurface drainage to mitigated wetlands at several sites in North Dakota. These two models were evaluated as possible tools for water resource managers to use for designing wetland mitigation projects in the area in the future.

The Soil-Plant-Atmosphere-Water (SPAW) model simulates the daily hydrologic water budgets of agricultural landscapes by two linked routines, one for farm fields (field hydrology) and one for impoundments such as wetlands and ponds (pond model). The DRAINMOD model was used in conjunction with the SPAW model because although the SPAW model can be used to simulate the hydrology of small drainage basins containing wetlands, the SPAW model does not contain routines to simulate drainage, either subsurface drainage or surface (drainage ditches), that can directly affect the wetland hydrology. The wetlands in the study areas in this report are all downstream from and adjacent to drained agricultural fields. SPAW and DRAINMOD models were developed and calibrated at three study areas (study areas B, D, and S) to evaluate how the models simulated field-scale hydrologic characteristics and the water balance in wetlands from January 1, 2003, through December 31, 2018.

The SPAW model developed for study area B included five modeled fields in the field hydrology portion of SPAW that contributed inflow to one wetland simulated in the pond model portion of SPAW. Simulated wetland water depths were most similar to water depths measured at site BWET1, with an absolute mean error of 0.10 foot and a root mean square error of 0.14 foot. Site BWET2 had slightly larger errors, with an absolute mean error of 0.22 foot and a root mean square error of 0.28 foot. Simulated water depths were similar to the pattern of measured water depths at BWET1 and BWET2 from about mid-April 2018 through about mid-September 2018, but overpredicted water depths in the fall from about mid-September 2018 through about mid-October 2018.

The SPAW model developed for study area D included six modeled fields in the field hydrology portion of SPAW that contributed inflow to five wetlands connected in series in the pond model portion of SPAW. Simulated water depths compared relatively well to water depths in the five wetlands, with the absolute mean error ranging from 0.17 foot (DWET1) to 0.39 foot (DWET2), and the root mean square error ranging from 0.28 foot (DWET1) to 0.56 foot (DWET5).

The SPAW model developed for study area S included one modeled field in the field hydrology portion of SPAW that contributed inflow to one wetland in the pond model portion of SPAW. Among the SPAW models developed for the three study areas, the model for study area S had the best comparison between simulated and measured water depths, with an absolute mean error of 0.06 foot and a root mean square error of 0.10 foot.

DRAINMOD models were developed and calibrated at the three study areas and provided inflow from subsurface drainage discharge to the SPAW models for simulating water levels in wetlands in the study areas. The calibrated DRAINMOD model for study area B showed the variability of hydrologic processes in the modeled field throughout the wide range of hydrologic conditions from January 1, 2003, through December 31, 2018. In general, the discharge through the modeled subsurface drainage system was in the spring and early summer (April through June) most years, with little to no discharge later in the year. Although the subsurface drainage system in study area D was the most complex among the three study areas and was simplified into a uniform system within DRAINMOD, simulated water table depths at study area D correlated better to measured water table depths compared to results from the model applications at the other two study areas. Simulated water table depths had an absolute mean error of 0.30 foot and root mean square error of 0.37 foot at site DGW1 and an absolute mean error of 0.29 foot and a root mean square error of 0.34 foot at site DGW2. Although the subsurface drainage system in study area S was the simplest and the modeled field was the smallest among the three study areas, simulated water table depths at study area S did not correlate as well to measured water table depths compared to results from the model applications at the other two study areas.

The SPAW and DRAINMOD model applications at the three study areas in southeast North Dakota adequately simulated the hydrologic processes for fields with subsurface drainage that are connected to adjacent wetlands. However, more measured data would be needed to fully evaluate the models throughout the range of possible climatic conditions.

Effect of the emergency drought barrier on the distribution, biomass, and grazing rate of the bivalves Corbicula fluminea and Potamocorbula amurensis, False River, California

Released September 15, 2021 07:48 EST

2021, Open-File Report 2021-1088

Francis Parchaso, Emily L. Zierdt Smith, Janet K. Thompson

Executive Summary

Benthic samples were collected from the Sacramento–San Joaquin Delta of northern California to examine the effect of the changing hydrologic flow on the bivalves Potamocorbula and Corbicula before, during, and after the False River Barrier (hereafter, barrier) was in operation (May–November 2015). Potamocorbula moved upstream in the Sacramento River as the salinity intruded. Given the lower electrical conductivity of the San Joaquin River, Potamocorbula did not move as far upriver as it did in the Sacramento River. Potamocorbula recruits settled in the Sacramento and False Rivers, whereas Corbicula recruits were mostly found in the San Joaquin River. When the grazing rates for the two bivalves were combined, new populations of Potamocorbula plus existing Corbicula likely reduced the net growth rate of the phytoplankton in and just upstream from the Sacramento and San Joaquin River confluence region when the barrier was in place. Prior to the barrier installation, a very dry period assumably aided the success of Potamocorbula in the confluence region; nonetheless, they also responded to the increasing salinity in the Sacramento River and their population spatially expanded. Potamocorbula’s upriver incursion was stopped owing to the return of freshwater flow due to the removal of the barrier, but the adults of the species were still present at the upstream end of Decker Island in January 2016. Corbicula adults did not seem to respond to the increased salinity caused by the barrier and maintained their biomass at all locations compared to what was recorded before the barrier.

Woods Hole Coastal and Marine Science Center—2020 annual report

Released September 14, 2021 15:30 EST

2021, Circular 1487

Sara Ernst

The 2020 annual report of the U.S. Geological Survey Woods Hole Coastal and Marine Science Center highlights accomplishments of 2020, includes a list of 2020 publications, and summarizes the work of the center, as well as the work of each of its science groups. This product allows readers to gain a general understanding of the focus areas of the center’s scientific research and learn more about specific projects and progress made throughout 2020, all while enjoying photographs taken in various environments and laboratories, and applicable maps and figures.

Continuous water-quality and suspended-sediment transport monitoring in the San Francisco Bay, California, water years 2018–19

Released September 14, 2021 13:37 EST

2021, Fact Sheet 2021-3043

Darin C. Einhell, Selina Davila Olivera, Danielle L. Palm

Water-Quality in San Francisco Bay

The U.S. Geological Survey (USGS) monitors water quality and suspended-sediment transport in the San Francisco Bay (Bay) as part of a multi-agency effort to address estuary management, water supply, and ecological concerns. The San Francisco Bay area is home to millions of people, and the Bay teems with marine and terrestrial flora and fauna. Freshwater mixes with saltwater in the Bay and is subject to riverine influences (floods, droughts, managed reservoir releases, and freshwater diversions) and marine influences (tides, waves, and effects of saltwater). To understand this environment, the USGS, along with its cooperators (see “Acknowledgments” section), has been monitoring the Bay’s waters continuously since 1988.

Analysis of Escherichia coli, total recoverable iron, and dissolved selenium concentrations, loading, and identifying data gaps for selected 303(d) listed streams, Grand Valley, western Colorado, 1980–2018

Released September 13, 2021 11:30 EST

2021, Scientific Investigations Report 2021-5053

Lisa D. Miller, Rachel G. Gidley, Natalie K. Day, Judith C. Thomas

Tributaries to the Colorado River in the Grand Valley in western Colorado (segment COLCLC13b) have been placed on the State of Colorado 303(d) list as impaired for Escherichia coli (E. coli), total recoverable iron, and dissolved selenium. The Colorado Department of Public Health and Environment Water Quality Control Division is required to develop total maximum daily loads for these constituents in these tributaries. The U.S. Geological Survey, in cooperation with the Grand Valley Drainage District and Colorado Water Conservation Board, conducted a study to (1) characterize concentrations, loads, and load reductions for E. coli, total recoverable iron, and dissolved selenium using existing data and (2) identify water-quality data gaps to inform future monitoring strategies. This study analyzed water-quality and streamflow data for 3 main-stem sites (2 sites along the Colorado River and 1 site along the Gunnison River) and 29 selected sites on tributaries to the Colorado River.

Sample data were available at five sites along Adobe Creek and at six sites along Leach Creek, the two tributaries in the study area that are impaired for E. coli. All geometric mean E. coli concentrations at sites along Adobe Creek and Leach Creek exceeded the State recreational use standard of 126 colony forming units per 100 milliliters (CFU/100 mL). In Adobe Creek, E. coli concentrations in samples ranged from 45.7 to more than 2,420 CFU/100 mL (method upper reporting limit for undiluted samples), and geometric mean concentrations at sites ranged from 301 to 1,180 CFU/100 mL. The E. coli concentrations generally increased in the downstream direction in Adobe Creek; however, increases were not seen between all sites. The largest downstream increase in E. coli concentration was measured between the two most upstream sites. In Leach Creek, concentrations of E. coli in samples ranged from 25.9 to more than 2,420 CFU/100 mL, and geometric mean concentrations at sites ranged from 160 to 259 CFU/100 mL. The E. coli concentrations showed no consistent downgradient increase in Leach Creek. In fact, some of the highest E. coli concentrations were measured at the most upstream site, Leach Creek at Summer Hill Drive.

Total recoverable iron concentrations and loads were evaluated at 15 tributary sites for samples collected from August 1993 to February 2018. Median total recoverable iron concentrations ranged from 211 to 4,670 micrograms per liter (µg/L). The chronic aquatic-life water-quality standard (1,000 µg/L) was exceeded in most irrigation season (April through October) samples but was rarely exceeded in nonirrigation season (November through March) samples. Concentrations were often an order of magnitude higher in samples collected during irrigation season than in samples collected during nonirrigation season. None of the sites had enough concurrent total recoverable iron and streamflow data to compute annual loads. As with E. coli, the lack of concurrent total recoverable iron and streamflow information represents a data gap, which needs to be addressed to compute annual loads.

Dissolved selenium concentrations and loads were evaluated at 20 tributary sites using discrete water-quality data collected 1991–2018. Dissolved selenium concentrations were higher during nonirrigation season than during irrigation season at tributary sites. However, irrigation season dissolved selenium loads were generally higher than nonirrigation selenium loads, because streamflows were higher during irrigation season. Regression analysis was used to estimate daily dissolved selenium concentrations and loads at three main-stem sites for water years (WYs) 1980–2018 (Gunnison River near Grand Junction and Colorado River near Colorado-Utah State Line) and WYs 2002–18 (Colorado River near Cameo). A trend analysis of dissolved selenium concentrations and loads was completed for these sites from the same respective starting dates but ending in 2017. A continuing downward trend in dissolved selenium concentration was observed at all sites and across all seasonal designations of the analysis. The dissolved selenium concentration decreased by 0.12 µg/L from WY 2002 to 2017 at Colorado River near Cameo, representing an 18-percent decrease during the time period. The dissolved selenium concentration at Gunnison River near Grand Junction decreased by 4.2 µg/L from WY 1980 to 2017, representing a 56-percent decrease overall. During the same time period, dissolved selenium concentration at Colorado River near Colorado-Utah State Line decreased by 3.8 µg/L, representing a 56-percent decrease overall. A downward trend in dissolved selenium load was also observed at all sites and across all seasonal designations of the analysis. The relative contribution of dissolved selenium from the Grand Valley near Grand Junction was estimated by comparing loads at main-stem sites bracketing the study area. The two upstream sites, Colorado River near Cameo and Gunnison River near Grand Junction, contributed 60,300 cumulative pounds and 251,000 cumulative pounds, respectively, during WYs 2002–18. At the furthest downstream site, Colorado River near Colorado-Utah State Line, 490,000 cumulative pounds were estimated during the same time period, indicating that the region between Whitewater and State line contributed approximately 179,000 cumulative pounds or a mean annual load of 10,500 lb/yr. Grand Valley dissolved selenium contributions appear to be stable during WYs 2002–18.

Storage capacity and sedimentation characteristics of Loch Lomond Reservoir, California, 2019

Released September 13, 2021 07:29 EST

2021, Scientific Investigations Report 2021-5081

Daniel R. Whealdon-Haught, Scott A. Wright, Mathieu D. Marineau

In May of 2019, Loch Lomond Reservoir was surveyed by the U.S. Geological Survey (USGS) in cooperation with the city of Santa Cruz to assess the current storage capacity and sedimentation rates in the reservoir. Survey methods combined sonar soundings to measure bathymetry and lidar scans with GPS data to measure near-shore topography and sediment bed samples to understand reservoir bed-material
size. The survey data produced a bare-earth digital elevation model (DEM) of the reservoir at a resolution of 1 square meter or better to elevations at or above the reservoir spillway elevation, providing the coverage needed to estimate storage capacity. Additionally, the USGS compared the current survey to storage estimates from historical surveys—particularly the most recent survey in 2009—to evaluate storage capacity trends. Lastly, a hindcast estimate of scaled sediment yield using sediment yields from the San Lorenzo River (USGS station 11160500)—where the San Lorenzo River watershed encompasses the Loch Lomond Reservoir watershed—were used to compare indirect estimates of storage loss to direct storage loss.

The 2019 survey resulted in a measured storage capacity of 8,770±50 acre-feet. The differences in storage between 2009 and 2019 varied substantially by depth. In shallow areas with depths less than 30 ft (at full reservoir), such as the very upstream end of the reservoir, storage loss (sediment deposition) dominated with a loss of about 68 acre-feet from 2009 to 2019. In areas deeper than 30 ft, persistent small storage gains over a wide range of depths totaled 82 acre-feet from 2009 to 2019.

Storage loss estimates derived from estimated watershed sediment yields and reservoir characteristics were similar to storage losses computed from past surveys. This hindcasting produced an estimate of about 500 acre-feet of total storage loss for the history of the reservoir, or an average of about 8–9 acre-feet/year during the 60-year period. For the period 2009–2019, the hindcast produced an estimated total storage loss of 42 acre-feet, which is broadly consistent with the 68 acre-feet of storage loss computed for shallow areas based on the repeat surveys.

Integrating seabird dietary and groundfish stock assessment data: Can puffins predict pollock spawning stock biomass in the North Pacific?

Released September 13, 2021 07:13 EST

2021, Fish and Fisheries

William J. Sydeman, Sarah Ann Thompson, John F. Piatt, Stephani Zador, Martin W. Dorn

Information on the annual variability in abundance and growth of juvenile groundfish can be useful for predicting fisheries stocks, but is often poorly known owing to difficulties in sampling fish in their first year of life. In the Western Gulf of Alaska (WGoA) and Eastern Bering Sea (EBS) ecosystems, three species of puffin (tufted and horned puffin, Fratercula cirrhata, Fratercula corniculata, and rhinoceros auklet, Cerorhinca monocerata, Alcidae), regularly prey upon (i.e., “sample”) age-0 groundfish, including walleye pollock (Gadus chalcogramma, Gadidae) and Pacific cod (Gadus microcephalus, Gadidae). Here, we test the hypothesis that integrating puffin dietary data with walleye pollock stock assessment data provides information useful for fisheries management, including indices of interannual variation in age-0 abundance and growth. To test this hypothesis, we conducted cross-correlation and regression analyses of puffin-based indices and spawning stock biomass (SSB) for the WGoA and EBS walleye pollock stocks. For the WGoA, SSB leads the abundance of age-0 fish in the puffin diet, indicating that puffins sample the downstream production of the WGoA spawning stock. By contrast, the abundance and growth of age-0 fish sampled by puffins lead SSB for the EBS stock by 1–3 years, indicating that the puffin diet proxies incoming year class strength for this stock. Our study indicates connectivity between the WGoA and EBS walleye pollock stocks. Integration of non-traditional data sources, such as seabird diet data, with stock assessment data appears useful to inform information gaps important for managing US fisheries in the North Pacific.

Altitude of the potentiometric surface in the Mississippi River Valley alluvial aquifer, spring 2020

Released September 13, 2021 06:56 EST

2021, Scientific Investigations Map 3478

Virginia L. McGuire, Ronald C. Seanor, William H. Asquith, Kellan R. Strauch, Anna M. Nottmeier, Judith C. Thomas, Roland W. Tollett, Wade H. Kress

The purpose of this report is to present a potentiometric-surface map for the Mississippi River Valley alluvial aquifer (MRVA). The source data for the map were groundwater-altitude data from wells measured manually or continuously generally in spring 2020 and from the altitude of the top of the water surface measured generally on April 9, 2020, in rivers in the area.

Forecasting drought probabilities for streams in the northeastern United States

Released September 10, 2021 14:10 EST

2021, Scientific Investigations Report 2021-5084

Samuel H. Austin

Maximum likelihood logistic regression (MLLR) models for the northeastern United States forecast drought probability estimates for water flowing in rivers and streams using methods previously identified and developed. Streamflow data from winter months are used to estimate chances of hydrological drought during summer months. Daily streamflow data collected from 1,143 streamgages from April 1, 1877, through October 31, 2018, are used to provide hydrological drought streamflow probabilities for July, August, and September as functions of streamflows during October, November, December, January, and February. This allows estimates of outcomes from 5 to 11 months ahead of their occurrence. Models specific to the northeastern United States were investigated and updated. The MLLR models of drought stream-flow probabilities utilize the explanatory power of temporally linked water flows. Models with strong drought streamflow probability correct-classification rates were produced for streams throughout the northeastern United States. A test of northeastern United States drought streamflow probability predictions found that overall correct-classification rates for drought streamflow probabilities in the northeastern United States exceeded 97 percent when predicting July 2019 drought probability using February 2019 monthly mean streamflow data. Using hydrological drought probability estimates in a water-management context informs understandings of possible future streamflow drought conditions in the northeastern United States, provides warnings of potential future drought conditions, and aids water-management decision making and responses to changing circumstances.

Streamflow and estimated loads of phosphorus and dissolved and suspended solids from selected tributaries to Lake Ontario, New York, water years 2012–14

Released September 10, 2021 12:40 EST

2016, Scientific Investigations Report 2016-5084

Brett A. Hayhurst, Benjamin N. Fisher, James E. Reddy

This report presents results of the evaluation and interpretation of hydrologic and water-quality data collected as part of a cooperative program between the U.S. Geological Survey and the U.S. Environmental Protection Agency. Streamflow, phosphorus, and solids dissolved and suspended in stream water were the focus of monitoring by the U.S. Geological Survey at 10 sites on 9 selected tributaries to Lake Ontario during the period from October 2011 through September 2014. Streamflow yields (flow per unit area) were the highest from the Salmon River Basin due to sustained yields from the Tug Hill aquifer. The Eighteenmile Creek streamflow yields also were high as a result of sustained base flow contributions from a dam just upstream of the U.S. Geological Survey monitoring station at Burt. The lowest streamflow yields were measured in the Honeoye Creek Basin, which reflects a decrease in flow because of withdrawals from Canadice and Hemlock Lakes for the water supply of the City of Rochester. The Eighteenmile Creek and Oak Orchard Creek Basins had relatively high yields due in part to groundwater contributions from the Niagara Escarpment and seasonal releases from the New York State Barge Canal.

Annual constituent yields (load per unit area) of suspended solids, phosphorus, orthophosphate, and dissolved solids were computed to assess the relative contributions and allow direct comparison of loads among the monitored basins. High yields of total suspended solids were attributed to agricultural land use in highly erodible soils at all sites. The Genesee River, Irondequoit Creek, and Honeoye Creek had the highest concentrations and largest mean yields of total suspended solids (165 short tons per square mile [t/mi2], 184 t/mi2, and 89.7 t/mi2, respectively) of the study sites.

Samples from Eighteenmile Creek, Oak Orchard Creek at Kenyonville, and Irondequoit Creek had the highest concentrations and largest mean yields of phosphorus (0.27 t/mi2, 0.26 t/mi2, and 0.20 t/mi2, respectively) and orthophosphate (0.17 t/mi2, 0.13 t/mi2, and 0.04 t/mi2, respectively) of the study sites. These results were attributed to a combination of sources, including discharges from wastewater treatment plants, diversions from the New York State Barge Canal, and manure and fertilizers applied to agricultural land. Yields of phosphorus also were high in the Genesee River Basin (0.17 t/mi2) and were presumably associated with nutrient and sediment transport from agricultural land and from streambank erosion. The Salmon and Black Rivers, which drain a substantial amount of forested land and are influenced by large groundwater discharges, had the lowest concentrations and yields of phosphorus and orthophosphate of the study sites.

Mean annual yields of dissolved solids were the highest in Irondequoit Creek due to a high percentage of urbanized area in the basin and in Oak Orchard Creek at Kenyonville and in Eighteenmile Creek due to groundwater contributions from the Niagara Escarpment. High yields of dissolved solids of 840 t/mi2, 829 t/mi2, and 715 t/mi2, respectively, from these basins can be attributed to seasonal chloride yields associated with use of road deicing salts. The Niagara Escarpment can produce large amounts of dissolved solids from the dissolution of minerals (a continual process reflected in base flow samples). Groundwater inflows in the Salmon River have very low concentrations of dissolved solids due to minimal bedrock interaction along the Tug Hill Plateau and discharge from the Tug Hill sand and gravel aquifer, which has minimal mineralization.

Phenotypic variation in Brook Trout Salvelinus fontinalis (Mitchill) at broad spatial scales makes morphology an insufficient basis for taxonomic reclassification of the species

Released September 09, 2021 09:01 EST

2021, Ichthyology & Herpetology (109) 743-751

Shannon Lynn White, David Kazyak, Richard C Harrington, Matt A. Kulp, Jacob M Rash, T. Casey Weathers, Thomas J Near

It was recently proposed that there are three new species of Salvelinus with microendemic distributions in the Great Smoky Mountains National Park, Tennessee, USA. The three species of Salvelinus were hypothesized to be distinct from their congener Brook Trout S. fontinalis based on three meristic traits—pored lateral-line scales, vertebral counts, and number of basihyal teeth. After analyses that included specimens sampled from a larger portion of the geographic range of S. fontinalis, we conclude that the three populations of Salvelinus recently described as new species are not morphometrically distinct from Brook Trout and consider all three to be synonyms of S. fontinalis. Moreover, the low number of specimens originally examined conflates morphological differences among populations with sexual dimorphism and/or phenotypic plasticity, both of which are documented extensively in Brook Trout but were not controlled for in the species descriptions. While there is currently insufficient phenotypic or genotypic evidence to support the hypothesis of three new species that are distinct from S. fontinalis, we acknowledge the need to understand the unique selection pressures that shape evolutionary trajectories in small, isolated populations of Brook Trout and to conserve evolutionarily significant sources of genotypic and phenotypic diversity. To that end, we provide comments on research opportunities to support Brook Trout conservation, including the importance of collaborative, range-wide phylogenetic studies to identify the most appropriate scales of management efforts.

If you give a clam an estuary: The story of potamocorbula

Released September 09, 2021 08:04 EST

2021, Frontiers for Young Minds

Kelly H. Shrader, Emily L. Zierdt Smith, Francis Parchaso, Janet K. Thompson

When you look at San Francisco Bay, what animals do you see? You may see lots of fish swimming around and birds flying above. What you DON’T see is Potamocorbula, a little clam that has had a big impact. Many years ago, ships accidentally brought Potamocorbula into the Bay. Pretty soon, Potamocorbula spread out all over in large numbers! Clams pump water over their gills and eat small particles of food, like phytoplankton, that pass through with the water. Potamocorbula can pump water much faster than other clams that live in the Bay, and they can eat more than their share of phytoplankton. Sometimes Potamocorbula eats phytoplankton faster than phytoplankton can grow! What problems does that cause for other animals, like birds and fish, that also need phytoplankton? Does Potamocorbula’s invasion only have negative impacts? In this article, we dive to the bottom of the Bay to find some answers. Book series publishing the chapter:

The structure and volume of large geysers in Yellowstone National Park, USA and the mineralogy and chemistry of their silica sinter deposits

Released September 09, 2021 07:50 EST

2021, Journal of Volcanology and Geothermal Research

Dakota Churchill, Michael Manga, Shaul Hurwitz, Sara Peek, David Damby, Richard Conrey, John R. Wood, R. Blaine McCleskey, William E. Keller, Behnaz Hosseini, Jefferson D.G. Hungerford

Siliceous sinter is formed by biogenic and abiogenic opal deposition around hot springs and geysers. Using Structure-from-Motion photogrammetry we generated three-dimensional models of Giant and Castle Geysers from the Upper Geyser Basin of Yellowstone National Park. We use these models to calculate an approximate mass of sinter for each (~2 and ~ 5 kton, respectively) and estimate a range of plausible long-term deposition rates for Castle Geyser (470 to 940 kg·yr−1). We estimate ~2% of the silica discharged from Castle Geyser is deposited as sinter in the cone and proximal terraces. We collected 15 sinter samples following the stratigraphy of each geyser from an older terrace to a younger cone and examined them using a variety of analytical methods. We find that young opaline sinter with a water content of <12 wt% (from loss on ignition) contains higher concentrations of major and trace elements, notably As, Sb, Rb, Ga and Cs, relative to older dehydrated sinter. Rare earth element (REE) concentrations in sinter are 2–3 orders of magnitude higher than in the thermal water from which they are deposited. Sinter deposits are enriched in light REE, Gd and Yb when normalized to concentrations in thermal water and enriched in Eu, Tm, and Yb when normalized to the underlying rhyolite. Sinter samples with the highest REE concentrations are also enriched in organic material, implying either microbial uptake of REE, or that organic molecules are efficient ligands that form metal complexes.

Estimating and forecasting time-varying groundwater recharge in fractured rock: A state-space formulation with preferential and diffuse flow to the water table

Released September 09, 2021 07:11 EST

2021, Water Resources Research

Allen M. Shapiro, Frederick Day-Lewis

Rapid infiltration following precipitation may result in groundwater contamination from surface contaminants or pathogens. In fractured rock, contaminants can migrate rapidly to points of groundwater withdrawals. In contrast to the temporal availability of groundwater quality chemical indicators, meteorological and groundwater level observations are available in real-time to estimate time-varying recharge, which can act as a surrogate to identify periods of rapid infiltration that may indicate contamination susceptibility. Estimating recharge using methods, such as base-flow recession, unsaturated infiltration models, or Water-Table Fluctuations (WTF), cannot capitalize on currently available technologies and telecommunication infrastructure to conduct real-time recharge estimation at scales relevant to characterizing rapid infiltration. We present a linear, physics-based State-Space (SS) model of one-dimensional infiltration to estimate recharge, which includes preferential and diffuse-flow to the water table. The model can take advantage of real-time data for water-table altitude, precipitation, and evapotranspiration. Model parameters are calibrated over an observation period, and the Kalman Filter (KF) is subsequently applied to continuously update the observed (water-table altitude) and unobserved (groundwater recharge) system states and predict future states as new data become available. The SS/KF algorithm is demonstrated at the Masser Groundwater Recharge Site in Pennsylvania, USA and comparisons are made with recharge estimates from WTF methods. Model results indicate that the frequency of observations (daily versus sub-daily) dictates the allocation between preferential and diffuse flow. Additionally, because infiltration processes encompass many nonlinearities, model parameters estimated from observation periods need to be updated at least seasonally to account for changing recharge conditions.

Global drivers of avian haemosporidian infections vary across zoogeographical regions

Released September 08, 2021 14:05 EST

2021, Global Ecology and Biogeography

Alan Fecchio, Nicholas J. Clark, Jeffrey A Bell, Heather Skeen, Holly L Lutz, Gabriel M De La Torre, Jefferson A Vaughan, Vasyl V. Tkach, Fabio Schunck, Francisco C Ferreira, Érika M Braga, Camile Lugarini, Wanyoike Wamiti, Janice H Dispoto, Spencer C Galen, Karin Kirchgatter, M. Cecilia Sagario, Victor R Cueto, Daniel González-Acuña, Mizue Inumaru, Yukita Sato, Yvonne R. Schumm, Petra Quillfeldt, Irene Pellegrino, Guha Dharmarajan, Pooja Gupta, V. V. Robin, Arif Ciloglu, Alparslan Yildirim, Xi Huang, Leonardo Chapa-Vargas, Paulina Álvarez-Mendizábal, Diego Santiago-Alarcon, Serguei Vyacheslavovich Drovetski, Olof Hellgren, Gary Voelker, Robert E Ricklefs, Shannon Hackett, Michael D Collins, Jason D Weckstein, Konstans Wells

Pauline Kamath, editor(s)

Aim: Macroecological analyses provide valuable insights into factors that influence how parasites are distributed across space and among hosts. Amid large uncertainties that arise when generalizing from local and regional findings, hierarchical approaches applied to global datasets are required to determine whether drivers of parasite infection patterns vary across scales. We assessed global patterns of haemosporidian infections across a broad diversity of avian host clades and zoogeographical realms to depict hotspots of prevalence and to identify possible underlying drivers.

Location: Global.

Time period: 1994–2019.

Major taxa studied: Avian haemosporidian parasites (genera Plasmodium, Haemoproteus, Leucocytozoon and Parahaemoproteus).

Methods: We amalgamated infection data from 53,669 individual birds representing 2,445 species world-wide. Spatio-phylogenetic hierarchical Bayesian models were built to disentangle potential landscape, climatic and biotic drivers of infection probability while accounting for spatial context and avian host phylogenetic relationships.

Results: Idiosyncratic responses of the three most common haemosporidian genera to climate, habitat, host relatedness and host ecological traits indicated marked variation in host infection rates from local to global scales. Notably, host ecological drivers, such as migration distance for Plasmodium and Parahaemoproteus, exhibited predominantly varying or even opposite effects on infection rates across regions, whereas climatic effects on infection rates were more consistent across realms. Moreover, infections in some low-prevalence realms were disproportionately concentrated in a few local hotspots, suggesting that regional-scale variation in habitat and microclimate might influence transmission, in addition to global drivers.

Main conclusions: Our hierarchical global analysis supports regional-scale findings showing the synergistic effects of landscape, climate and host ecological traits on parasite transmission for a cosmopolitan and diverse group of avian parasites. Our results underscore the need to account for such interactions, in addition to possible variation in drivers across regions, to produce the robust inference required to predict changes in infection risk under future scenarios.

Thermal stability of an adaptable, invasive ectotherm: Argentine giant tegus in the Greater Everglades ecosystem, USA

Released September 08, 2021 11:53 EST

2021, Ecosphere (12) 1-18

Andrea Faye Currylow, Michelle Collier, Emma B. Hanslowe, Bryan G. Falk, Brian S. Cade, Sarah E. Moy, Alejandro Grajal-Puche, Frank N. Ridgley, Robert Reed, Amy A. Yackel Adams

Invasive species globally threaten biodiversity and economies, but the ecophysiological mechanisms underlying their success are often understudied. For those alien species that also exhibit high phenotypic plasticity, such as habitat generalists, adaptations in response to environmental pressures can take place relatively quickly. The Argentine giant tegu (Salvator merianae; tegu) is a large omnivorous lizard from South America that is prolific, long-lived, vagile, and highly adaptable to disturbed environments. They are well suited to the climate of southeastern United States, introduced to several disjunct areas, including the Everglades, where their voracious appetite threatens native wildlife. Tegus undergo winter dormancy (hibernation) to cope with colder temperatures, and while this behavior may facilitate invasion into more temperate regions, it may also present management opportunities. We studied the thermal habits of wild S. merianae within their invaded range in southern Florida, USA. We used radiotelemetry and trail cameras to verify aboveground behaviors, and temperature dataloggers to monitor surface (sun-exposed [Te] and shaded [Ts]), ambient (Ta), subsurface ground (Th), and internal body (Tb) temperatures of a population of free-ranging tegus over several seasons. We evaluated thermal and behavioral data and identified five biologically significant periods: pre-hibernal, hibernal, cold snaps, hibernal-basking, and post-hibernal. We found tegus maintained thermal stability throughout the hibernal period, frequently at temperatures above available thermal microhabitats. Variation in Tb was lowest during hibernation and cold snaps and was less variable than subsurface temperatures despite not leaving their hibernaculum. Hibernal ingress and egress were best predicted by temperature differentials between exposed soil and ambient daily mean temperatures (Te − Ta) and daylength. Though we detected no sex differences, larger animals started hibernation sooner, stayed in hibernation longer, and retained higher fat stores over the study period. One individual did not hibernate, representing only the second record of this behavior. Despite limitations of these descriptive data, this is the first study finely detailing Tb of a population of wild, free-ranging S. merianae over multiple biologically significant time periods and to associate Tb with thermal habitats within its invasive range. Tegus' apparent ability for thermal stability expands the adaptability breadth of this species and underscores the invasion threat.

Detrital signals of coastal erosion and fluvial sediment supply during glacio-eustatic sea-level rise, Southern California, USA

Released September 08, 2021 08:14 EST

2021, Geology

Glenn R. Sharman, Jacob A Covault, Daniel F. Stockli, Zack Sickmann, Matthew A. Malkowski, Samuel A. Johnstone

Coastal erosion, including sea-cliff retreat, represents both an important component of some sediment budgets and a significant threat to coastal communities in the face of rising sea level. Despite the importance of predicting future rates of coastal erosion, few prehistoric constraints exist on the relative importance of sediment supplied by coastal erosion versus rivers with respect to past sea-level change. We used detrital zircon U-Pb geochronology as a provenance tracer of river and deep-sea fan deposits from the Southern California Borderland (United States) to estimate relative sediment contributions from rivers and coastal erosion from late Pleistocene to present. Mixture modeling of submarine canyon and fan samples indicates that detrital zircon was dominantly (55%–86%) supplied from coastal erosion during latest Pleistocene (ca. 13 ka) sea-level rise, with lesser contributions from rivers, on the basis of unique U-Pb age modes relative to local Peninsular Ranges bedrock sources. However, sediment that was deposited when sea level was stable at its highest and lowest points since the Last Glacial Maximum was dominantly supplied by rivers, suggesting decreased coastal erosion during periods of sea-level stability. We find that relative sediment supply from coastal erosion is strongly dependent on climate state, corroborating predictions of enhanced coastal erosion during future sea-level rise.

Advancing cave detection using terrain analysis and thermal imagery

Released September 08, 2021 07:47 EST

2021, Remote Sensing (13)

J. Judson Wynne, Jeff Jenness, Derek Sonderegger, Timothy N. Titus, Murzy D. Jhabvala, Nathalie A. Cabrol

Since the initial experiments nearly 50 years ago, techniques for detecting caves using airborne and spacecraft acquired thermal imagery have improved markedly. These advances are largely due to a combination of higher instrument sensitivity, modern computing systems, and processor-intensive analytical techniques. Through applying these advancements, our goals were to: (1) Determine the efficacy of methods designed for terrain analysis and applied to thermal imagery; (2) evaluate the usefulness of predawn and midday imagery for detecting caves; and (3) ascertain which imagery type (predawn, midday, or the difference between those two times) was most informative. Using forward stepwise logistic (FSL) and Least Absolute Shrinkage and Selection Operator (LASSO) regression analyses for model selection, and a thermal imagery dataset acquired from the Mojave Desert, California, we examined the efficacy of three well-known terrain descriptors (i.e., slope, topographic position index (TPI), and curvature) on thermal imagery for cave detection. We also included the actual, untransformed thermal DN values (hereafter “unenhanced thermal”) as a fourth dataset. Thereafter, we compared the thermal signatures of known cave entrances to all non-cave surface locations. We determined these terrain-based analytical methods, which described the “shape” of the thermal landscape, hold significant promise for cave detection. All imagery types produced similar results. Down-selected covariates per imagery type, based upon the FSL models, were: Predawn— slope, TPI, curvature at 0 m from cave entrance, as well as slope at 1 m from cave entrance; midday— slope, TPI, and unenhanced thermal at 0 m from cave entrance; and difference— TPI and slope at 0 m from cave entrance, as well as unenhanced thermal and TPI at 3.5 m from cave entrance. We provide recommendations for future research directions in terrestrial and planetary cave detection using thermal imagery.

Digital elevation models: Terminology and definitions

Released September 08, 2021 07:27 EST

2021, Remote Sensing (13)

Peter L. Guth, Adriaan Van Niekerk, Carlos H. Grohmann, Jan-Peter Muller, Laurence Hawker, Igor V. Florinsky, Dean B. Gesch, Hannes I. Reuter, Virginia Herrera-Cruz, Serge Riazanoff, Carlos López-Vázquez, Claudia C. Carabajal, Clément Albinet, Peter Strobl

Digital elevation models (DEMs) provide fundamental depictions of the three-dimensional shape of the Earth’s surface and are useful to a wide range of disciplines. Ideally, DEMs record the interface between the atmosphere and the lithosphere using a discrete two-dimensional grid, with complexities introduced by the intervening hydrosphere, cryosphere, biosphere, and anthroposphere. The treatment of DEM surfaces, affected by these intervening spheres, depends on their intended use, and the characteristics of the sensors that were used to create them. DEM is a general term, and more specific terms such as digital surface model (DSM) or digital terrain model (DTM) record the treatment of the intermediate surfaces. Several global DEMs generated with optical (visible and near-infrared) sensors and synthetic aperture radar (SAR), as well as single/multi-beam sonars and products of satellite altimetry, share the common characteristic of a georectified, gridded storage structure. Nevertheless, not all DEMs share the same vertical datum, not all use the same convention for the area on the ground represented by each pixel in the DEM, and some of them have variable data spacings depending on the latitude. This paper highlights the importance of knowing, understanding and reflecting on the sensor and DEM characteristics and consolidates terminology and definitions of key concepts to facilitate a common understanding among the growing community of DEM users, who do not necessarily share the same background. 

Mapping critical minerals from the sky

Released September 08, 2021 07:23 EST

2021, GSA Today (31)

Anjana K. Shah, Robert Morrow, Michael Pace, M.Scott Harris, William Doar III

Critical mineral resources titanium, zirconium, and rare earth elements occur in placer deposits over vast parts of the U.S. Atlantic Coastal Plain. Key questions regarding provenance, pathways of minerals to deposit sites, and relations to geologic features remain unexplained. As part of a national effort to collect data over regions prospective for critical minerals, the first public high-resolution aeroradiometric survey over the U.S. Atlantic Coastal Plain was conducted over Quaternary sediments in South Carolina. The new data provide an unprecedented view of potential deposits by imaging Th-bearing minerals in the heavy mineral assemblage. Sand ridges show the highest radiometric Th values with localized, linear anomalies, especially along the shoreface and in areas reworked by multiple processes and/or during multiple episodes. Estuarine areas with finer-grained sediments show lower, distributed Th anomalies. Th values averaged over geologic unit areas are similar for both environments, suggesting that heavy minerals are present but have not been locally concentrated in the lower-energy estuarine environments. Radiometric K highlights immature minerals such as mica and potassium feldspar. K is elevated within shallow sediments younger than ca. 130 ka, an attribute that persists in regional data from northern South Carolina to northern Florida. Both K and Th are elevated over the floodplains of the Santee River and other rivers with headwaters in the igneous and metamorphic Piedmont Terrane. The persistence of K anomalies for distances of more than 100 km from the Santee River floodplain suggests that heavy minerals are delivered from the Piedmont to offshore areas by major rivers, transported along the coast by the longshore current, and redeposited onshore by marine processes.

The application of metacommunity theory to the management of riverine ecosystems

Released September 08, 2021 07:01 EST

2021, WIREs Water

Christopher J. Patrick, Kurt E. Anderson, Brown L. Brown, Charles P. Hawkins, Anya Metcalfe, Parsa Saffarinia, Tadeu Siqueira, Christopher M. Swan, Jonathan D. Tonkin, Lester L. Yuan

River managers strive to use the best available science to sustain biodiversity and ecosystem function. To achieve this goal requires consideration of processes at different scales. Metacommunity theory describes how multiple species from different communities potentially interact with local-scale environmental drivers to influence population dynamics and community structure. However, this body of knowledge has only rarely been used to inform management practices for river ecosystems. In this article, we present a conceptual model outlining how the metacommunity processes of local niche sorting and dispersal can influence the outcomes of management interventions and provide a series of specific recommendations for applying these ideas as well as research needs. In all cases, we identify situations where traditional approaches to riverine management could be enhanced by incorporating an understanding of metacommunity dynamics. A common theme is developing guidelines for assessing the metacommunity context of a site or region, evaluating how that context may affect the desired outcome, and incorporating that understanding into the planning process and methods used. To maximize the effectiveness of management activities, scientists, and resource managers should update the toolbox of approaches to riverine management to reflect theoretical advances in metacommunity ecology.

Streamflow—Water year 2020

Released September 07, 2021 19:14 EST

2021, Fact Sheet 2021-3046

Xiaodong Jian, David M. Wolock, Harry F. Lins, Ronald J. Henderson, Steven J. Brady

The maps and graphs in this summary describe national streamflow conditions for water year 2020 (October 1, 2019, to September 30, 2020) in the context of streamflow ranks relative to the 91-year period of water years 1930–2020. Annual runoff in the Nation’s rivers and streams during water year 2020 (11.10 inches) was higher than the long-term (1930–2020) mean annual runoff of 9.40 inches for the contiguous United States. Nationwide, the 2020 streamflow ranked the 10th highest out of the 91 years.

A machine learning approach to modeling streamflow with sparse data in ungaged watersheds on the Wyoming Range, Wyoming, 2012–17

Released September 07, 2021 19:13 EST

2021, Scientific Investigations Report 2021-5093

Ryan R. McShane, Cheryl A. Eddy-Miller

Scant availability of streamflow data can impede the utility of streamflow as a variable in ecological models of aquatic and terrestrial species, especially when studying small streams in watersheds that lack streamgages. Streamflow data at fine resolution and broad extent were needed by collaborators for ecological research on small streams in several ungaged watersheds of southwestern Wyoming, where streamflow data are sparse.

To improve the utility of sparse streamflow data to ecological research in ungaged watersheds, we developed a machine learning approach in R for modeling spatially and temporally continuous monthly streamflow from 2012 through 2017 in three semiarid montane-steppe watersheds (with drainage areas of 26–55 square miles and mean elevations of 8,031–8,455 feet) on the Wyoming Range in the upper Green River Basin. A machine learning streamflow (MLFLOW) model was calibrated and validated with 971 discrete streamflow observations and 24 static and dynamic predictor variables derived from geospatial and time series data on climatic, physiographic, and anthropogenic characteristics affecting streamflow. The predictor variables were temporally and spatially conditioned to amplify the relation of predictor variables to monthly streamflow.

The MLFLOW model had satisfactory agreement between observed and predicted streamflow (coefficient of determination [R2]=0.80, Nash-Sutcliffe efficiency [NSE]=0.79, NSE with log-transformed data [logNSE]=0.82, and percent bias [PBIAS]=0.7 percent). NSE and logNSE indicated the MLFLOW model performed equally well for high and low flows, and PBIAS indicated the MLFLOW model did not overpredict or underpredict monthly streamflow. Streamflow predictions seemed to well represent the annual hydrograph within the study area during the study period.

The most important variables (statistically important in the MLFLOW model) for explaining monthly streamflow were temporally and spatially conditioned dynamic climatic variables, mostly precipitation and snow water equivalent. Importance of the static and dynamic variables did not differ substantially among the three watersheds but differed considerably among the 6 years. Monthly streamflow increased with increasing precipitation, snow water equivalent, and drainage area but decreased with increasing forest cover, elevation, evapotranspiration, and temperature.

The MLFLOW model was most sensitive to selection of dynamic climatic variables. Unconditioned dynamic climatic variables alone explained 54 percent of the variance (R2=0.54) in monthly streamflow, whereas adding static physiographic and anthropogenic variables only explained 12 percent more of the variance (R2=0.66). Also, spatial conditioning of all variables together with temporal conditioning of dynamic variables increased the variance explained in the MLFLOW model by another 14 percent (R2=0.80). The MLFLOW model also had greater sensitivity to temporal than to spatial differences in the data. For the MLFLOW model trained with observations from all watersheds and years or for models trained with observations from all except one watershed or 1 year left out sequentially, performance was better in testing on observations from each watershed than from each year separately. Also, performance was better for models fitted to fewer sites than to fewer months of observations.

The greatest utility of the modeling approach is the ease of use and the speed of processing input data, running the model, and interpreting the model output, whereas the greatest limitation is the need for spatially and temporally representative streamflow observations to drive the model. Although familiarity with R is necessary, only a working knowledge of hydrology (for selecting appropriate predictor variables and evaluating the quality of streamflow observations) and a rudimentary understanding of machine learning models are needed. Therefore, this modeling approach is practicable for other scientists who work with water but who are not hydrologists.

Rigorously valuing the coastal hazard risks reduction provided by potential coral reef restoration in Florida and Puerto Rico

Released September 07, 2021 16:54 EST

2021, Open-File Report 2021-1054

Curt D. Storlazzi, Borja G. Reguero, Kristen A. Cumming, Aaron D. Cole, James B. Shope, Camila Gaido L., T. Shay Viehman, Barry A. Nickel, Michael W. Beck

The restoration of coastal habitats, particularly coral reefs, can reduce risks by decreasing the exposure of coastal communities to flooding hazards. In the United States, the protective services provided by coral reefs were recently assessed in social and economic terms, with the annual protection provided by U.S. coral reefs off the coasts of the State of Florida and the Commonwealth of Puerto Rico estimated to be more than 9,800 people and $859 million (2010 U.S. dollars). Hurricanes Irma and Maria in 2017 caused widespread damage to coral reefs in the State of Florida and the Commonwealth of Puerto Rico. Here we combine engineering, ecologic, geospatial, social, and economic data and tools to provide a rigorous valuation of where potential coral reef restoration could decrease the hazard faced by Florida and Puerto Rico’s reef-fronted coastal communities. The three restoration scenarios considered: (1) Ecological restoration, ‘E25’, which assumes planting 0.25-meter (m)-high corals on a (cross-shore) 25-m-wide reef; (2) Structural plus ecological, ‘S25’, which assumes emplacing a 1.00-m high structure with 0.25-m high corals on top on a 25 m wide reef; and (3) structural plus ecological, ‘S05’, which assumes emplacing a 1.00-m high structure with 0.25-m high corals on top on a 5 m wide reef. Planted corals are assumed to increase hydrodynamic roughness, thereby dissipating incident wave energy and decreasing flooding potential. We used a standardized approach to ‘place’ potential restoration projects throughout the whole (linear) extent of reefs bordering Florida and Puerto Rico to identify where coral reef restoration could be useful for meeting flood reduction benefits. We always sited potential restoration projects within the existing distribution of reefs even though many sites were far (kilometers [km]) offshore and some sites were relatively deep (up to 7 m depth). We followed risk-based valuation approaches to map flood zones at 10-square-meter resolution along all 980 km of Florida and Puerto’s Rico reef-lined shorelines for the three potential coral reef restoration scenarios and compare them to the flood zones without coral reef restoration. We quantified the potential coastal flood risk reduction provided by coral reef restoration using the latest information from the U.S. Census Bureau, Federal Emergency Management Agency, and Bureau of Economic Analysis for return-interval storm events. Using the damages associated with each storm probability, we also calculate the change in annual expected damages, a measure of the annual protection gained because of coral reef restoration. We found that the benefits of reef restoration off Florida and Puerto Rico are spatially highly variable. In most areas, we found little or no benefit from reef restoration (for example, restoration sites were far offshore or deep). However, there were a number of key areas where reef restoration could have substantial benefits for flood risk reduction. In particular, we estimated the protection gained by Florida and Puerto Rico’s coral reefs from coral reef restoration to result in:

  • Avoided flooding to more than 5.6 square kilometers (2.16 square miles) of land annually;
  • Avoided flooding affecting more than 3,100 people annually;
  • Avoided direct damages of more than $124.2 million to more than 890 buildings annually; and
  • Avoided indirect damages to more $148.7 million in economic activity owing to housing and business damage annually.

Thus, the annual value of flood risk reduction provided by potential coral reef restoration in Florida and Puerto Rico is more than 3,100 people and $272.9 million (2010 U.S. dollars) in economic activity. These data provide stakeholders and decision makers with a spatially explicit, rigorous valuation of how, where, and when potential coral reef restoration in Florida and Puerto Rico can increase critical coastal storm flood reduction benefits. These results help identify areas where reef management, recovery, and restoration could potentially help reduce the risk to, and increase the resiliency of, Florida and Puerto Rico’s coastal communities.

Rigorously valuing the impact of projected coral reef degradation on coastal hazard risk in Florida

Released September 07, 2021 16:53 EST

2021, Open-File Report 2021-1055

Curt D. Storlazzi, Borja G. Reguero, Kimberly K. Yates, Kristen A. Cumming, Aaron D. Cole, James B. Shope, Camila Gaido L., David G. Zawada, Stephanie R. Arsenault, Zachery W. Fehr, Barry A. Nickel, Michael W. Beck

The degradation of coastal habitats, particularly coral reefs, raises risks by increasing the exposure of coastal communities to flooding hazards. In the United States, the physical protective services provided by coral reefs were recently assessed, in social and economic terms, with the annual protection provided by U.S. coral reefs off the coast of the State of Florida estimated to be more than 5,600 people and $675 million (2010 U.S. dollars). Degradation of coral reef ecosystems over the past several decades and during tropical storm events has caused regional-scale erosion of the shallow seafloor that serves as a protective barrier against coastal hazards along Southeast Florida, increasing risks to coastal populations. Here we combine engineering, ecologic, geospatial, social, and economic data and tools to provide a rigorous valuation of the increased hazard faced by Florida’s reef-fronted coastal communities because of the projected degradation of its adjacent coral reefs. We followed risk-based valuation approaches to map flood zones at 10-square-meter resolution along all 430 kilometers of Florida’s reef-lined shorelines for both the current and projected future coral reef conditions. We quantified the coastal flood risk increase caused by coral reef degradation using the latest information from the U.S. Census Bureau, Federal Emergency Management Agency, and Bureau of Economic Analysis for return-interval storm events. Using the damages associated with each storm probability, we also calculated the change in annual expected damages, a measure of the annual protection lost because of projected coral reef degradation. We found that degradation of the coral reefs off Florida increases future risks significantly. In particular, we estimated the protection lost by Florida’s coral reefs from projected coral reef degradation will result in:

  • Increased flooding to more than 8.77 square kilometers (3.39 square miles) of land annually;
  • Increased flooding affecting more than 7,300 people annually;
  • Increased direct damages of more than $385.4 million to more than 1,400 buildings annually; and
  • Increased indirect damages to more $438.1 million in economic activity owing to housing and business damage annually.

Thus, the annual value of increased flood risk caused by the projected degradation of Florida’s coral reefs is more than 7,300 people and $823.6 million (2010 U.S. dollars). These data provide stakeholders and decision makers with a spatially explicit, rigorous valuation of how, where, and when degradation of Florida’s coral reefs will decrease critical coastal storm flood reduction benefits. These results help identify areas where reef management, recovery, and restoration could potentially help reduce the risk to, and increase the resiliency of, Florida’s coastal communities.

Rigorously valuing the impact of Hurricanes Irma and Maria on coastal hazard risks in Florida and Puerto Rico

Released September 07, 2021 16:52 EST

2021, Open-File Report 2021-1056

Curt D. Storlazzi, Borja G. Reguero, T. Shay Viehman, Kristen A. Cumming, Aaron D. Cole, James B. Shope, Sarah H. Groves, Camila Gaido L., Barry A. Nickel, Michael W. Beck

The degradation of coastal habitats, particularly coral reefs, raises risks by increasing the exposure of coastal communities to flooding hazards. In the United States, the physical protective services provided by coral reefs were recently assessed in social and economic terms, with the annual protection provided by U.S. coral reefs off the coasts of the State of Florida and the Commonwealth of Puerto Rico estimated to be more than 9,800 people and $859 million (2010 U.S. dollars). Hurricanes Irma and Maria in 2017 caused widespread damage to coral reefs in the State of Florida and the Commonwealth of Puerto Rico. These damages were measured in post-storm surveys of reefs and assessed in terms of their impact on reef condition and height, which are critical parameters for evaluating the coastal defense benefits of reefs. We combined engineering, ecologic, geospatial, social, and economic data and tools to value the increased risks in Florida and Puerto Rico from hurricane-induced damages to their adjacent coral reefs. We followed risk-based valuation approaches to map flooding at 10-square-meter resolution along all 980 kilometers of Florida and Puerto Rico’s reef-lined shorelines considering reef condition before (undamaged) and after (damaged) the 2017 hurricanes. We quantified the coastal flood risk increase caused by the hurricane-induced damage to the coral reefs using the latest information from the U.S. Census Bureau, Federal Emergency Management Agency, and Bureau of Economic Analysis for return-interval storm events. Using the damages associated with each storm probability, we also calculated the change in annual expected damages, a measure of the annual protection lost because of the reef damage caused by the 2017 hurricanes. We found that the damages to the coral reefs off Florida and Puerto Rico from Hurricanes Irma and Maria increased future risks significantly. In particular, we estimated the protection lost by Florida and Puerto Rico’s coral reefs from the 2017 hurricanes to result in:

  • Increased flooding to more than 10.72 square kilometers (4.14 square miles) of land annually;
  • Increased flooding affecting more than 4,300 people annually;
  • Increased direct damages of more than $57.2 million to more than 1,800 buildings annually; and
  • Increased indirect damages to more $124.3 million in economic activity owing to housing and business damage annually.

Thus, the annual value of increased flood risk caused by the damage to Florida and Puerto Rico’s coral reefs from hurricanes in 2017 is more than 4,300 people and $181.5 mil-lion (2010 U.S. dollars) in economic impacts. These data provide stakeholders and decision makers with a spatially explicit, rigorous valuation of how, where, and when the damage from the 2017 hurricanes decreased critical coastal storm flood reduction benefits to Florida and Puerto Rico’s coral reefs. These results help identify areas where reef management, recovery, and restoration could potentially help reduce the risk to, and increase the resiliency of, Florida and Puerto Rico’s coastal communities.

Intraspecific variation mediates density dependence in a genetically diverse plant species

Released September 07, 2021 11:08 EST

2021, Ecology

Andrii Zaiats, Matthew Germino, Marcelo D Serpe, Bryce Richardson, Trevor Caughlin

Interactions between neighboring plants are critical for biodiversity maintenance in plant populations and communities. Intraspecific trait variation and genome duplication are common in plant species and can drive eco-evolutionary dynamics through genotype-mediated plant–plant interactions. However, few studies have examined how species-wide intraspecific variation may alter interactions between neighboring plants. We investigate how subspecies and ploidy variation in a genetically diverse species, big sagebrush (Artemisia tridentata), can alter the demographic outcomes of plant interactions. Using a replicated, long-term common garden experiment that represents range-wide diversity of A. tridentata, we ask how intraspecific variation, environment, and stand age mediate neighbor effects on plant growth and survival. Spatially explicit models revealed that ploidy variation and subspecies identity can mediate plant–plant interactions but that the effect size varied in time and across experimental sites. We found that demographic impacts of neighbor effects were strongest during early stages of stand development and in sites with greater growth rates. Within subspecies, tetraploid populations showed greater tolerance to neighbor crowding compared to their diploid variants. Our findings provide evidence that intraspecific variation related to genome size and subspecies identity impacts spatial demography in a genetically diverse plant species. Accounting for intraspecific variation in studies of conspecific density dependence will improve our understanding of how local populations will respond to novel genotypes and biotic interaction regimes. As introduction of novel genotypes into local populations becomes more common, quantifying demographic processes in genetically diverse populations will help predict long-term consequences of plant–plant interactions.

Pedigree accumulation analysis: Combining methods from community ecology and population genetics for breeding adult estimation

Released September 07, 2021 10:51 EST

2021, Methods in Ecology and Evolution

Nicholas Sard, Robert D. Hunter, Edward F. Roseman, Daniel B. Hayes, Robin L . DeBruyne, Kim T Scribner

  1. Estimates of the number of successfully breeding adults (NS) in a population can predict levels of recruitment. However, assessments of NS are often difficult to obtain because encounters with adults are limited due to life-history characteristics, low abundance or other constraints associated with access to critical habitats. Alternatively, efforts to sample individuals at earlier ontogenetic stages can be more tractable, resulting in more comprehensive samples.
  2. To estimate NS, we describe, evaluate and apply two nonparametric species richness estimators to information associated with genetic pedigree reconstruction. Simulations compared bias and precision associated with Chao and Jackknife methods when estimating NS. We also evaluated NS estimation sensitivity to two sources of variation associated with species reproductive ecology (variance in reproductive success and sex ratio skew) and genetic pedigree assignment error. Finally, the application of our novel method was demonstrated in two different species and systems (Chinook Salmon in Oregon, USA and Lake Sturgeon in Michigan, USA).
  3. We found unbiased NS estimates were generated across a broad range of offspring sample sizes using the Chao method. Empirical results corroborated simulation-based expectations and highlighted applications where parents and offspring are sampled, and when only offspring are sampled.
  4. When offspring sample sizes are adequate and pedigree reconstruction errors are low, the combination of established methods from community ecology and genetic pedigree reconstruction provides an accurate alternative method to estimate NS that can facilitate population assessments.

Geologic framework of Mount Diablo, California

Released September 07, 2021 10:48 EST

2021, Book chapter, Regional geology of Mount Diablo, California: Its tectonic evolution on the North America plate boundary

Russell Graymer, Victoria Langenheim

The basic stratigraphic and structural framework of Mount Diablo is described using a revised geologic map, gravity data, and aeromagnetic data. The mountain is made up of two distinct stratigraphic assemblages representing different depocenters that were juxtaposed by ~20 km of late Pliocene and Quaternary right-lateral offset on the Greenville-Diablo-Concord fault. Both assemblages are composed of Cretaceous and Cenozoic strata overlying a compound basement made up of the Franciscan and Great Valley complexes. The rocks are folded and faulted by late Neogene and Quaternary compressional structures related to both regional plate-boundary–normal compression and a restraining step in the strike-slip fault system. The core of the mountain is made up of uplifted basement rocks. Late Neogene and Quaternary deformation is overprinted on Paleogene extensional deformation that is evidenced at Mount Diablo by significant attenuation in the basement rocks and by an uptilted stepped graben structure on the northeast flank. Retrodeformation of the northeast flank suggests that late Early to early Late Cretaceous strata may have been deposited against and across a steeply west-dipping basement escarpment. The location of the mountain today was a depocenter through the Late Cretaceous and Paleogene and received shallow-marine deposits periodically into the late Miocene. Uplift of the mountain itself happened mostly in the Quaternary.

Post-fire temporal trends in soil-physical and -hydraulic properties and simulated runoff generation: Insights from different burn severities in the 2013 Black Forest Fire, CO, USA

Released September 07, 2021 10:38 EST

2022, Science of the Total Environment (802) 1-14

Brian A. Ebel, John A. Moody, Deborah A. Martin

Burn severity influences on post-fire recovery of soil-hydraulic properties controlling runoff generation are poorly understood despite the importance for parameterizing infiltration models. We measured soil-hydraulic properties of field-saturated hydraulic conductivity (Kfs), sorptivity (S), and wetting front potential (ψf) for four years after the 2013 Black Forest Fire, Colorado, USA at six sites across a gradient of initial remotely sensed burn severity using the change in the normalized burn ratio (dNBR). These measurements were correlated with soil-physical property measurements of bulk density (ρb), loss on ignition (LOI, a measure of soil organic matter), and ground cover composition to provide insight into causal factors for temporal changes in Kfs, S, and ψf . Modeled infiltration using the Smith-Parlange approach parameterized with measured Kfs, S, and ψf further discerned the role of precipitation intensity on runoff generation. Temporal trends of soil-physical properties and ground cover showed influences from initial burn severity. Trends in soil-hydraulic properties , surprisingly, were not strongly influenced by initial burn severity despite inferred effects of ρb, LOI, and ground cover on trends in Kfs and S. Calculations of dNBR at the time of sampling showed strong correlations with Kfs and S, demonstrating a new approach for estimating long-unburned Kfs and S values, infiltration model parameters after fire, and assessing the time of return to pre-fire values. Simulated infiltration-excess runoff, in contrast, did depend on initial burn severity. Time series of the ratio S2/Kfs ≈ ψf tended to converge between 1 to 10 mm four years after wildfire, potentially (i) defining a long-unburned forest domain of S2/Kfs and ψf from 1 to 10 mm with relatively high Kfs values, and (ii) providing a new post-fire soil-hydraulic property recovery metric (i.e. S2/Kfs ≈ ψf in the range of 1 to 10 mm) for sites in the Rocky Mountains of the USA.

Geologic map of Olympus Mons caldera, Mars

Released September 07, 2021 10:02 EST

2021, Scientific Investigations Map 3470

Peter J. Mouginis-Mark

The Mars volcano, Olympus Mons, is probably the best known extraterrestrial volcano. The summit forms a nested caldera with six overlapping collapse pits that collectively measure ~65 x ~80 kilometers (km). Numerous wrinkle ridges and graben occur on the caldera floor, and topographic data indicate >1.2 km of elevation change since the formation of the floor as a series of lava lakes. The paths of lava flows on the south and southeast flanks do not conform to present-day topography. Mapping at a scale of 1:200,000 shows that the summit area displays a complex volcanic history that has  numerous similarities to terrestrial shield volcanoes. Pangboche crater is a large (~10-km-diameter) crater of impact origin that lies on the south flank of the caldera and, because of the elevation and lack of volatiles, it displays numerous features more similar to fresh lunar craters than to impact craters on Mars.

Evidence for interannual persistence of infectious influenza A viruses in Alaska wetlands

Released September 07, 2021 09:34 EST

2022, Science of the Total Environment (803)

Andrew M. Ramey, Andrew B. Reeves, Benjamin Joel Lagassé, Vijay P. Patil, Laura E. Hubbard, Dana W. Kolpin, R. Blaine McCleskey, Deborah A. Repert, David E. Stallknecht, Rebecca L. Poulson

Influenza A viruses (IAVs) deposited by wild birds into the environment may lead to sporadic mortality events and economically costly outbreaks among domestic birds. There is a paucity of information, however, regarding the persistence of infectious IAVs within the environment following deposition. In this investigation, we assessed the persistence of 12 IAVs that were present in the cloaca and/or oropharynx of naturally infected ducks. Infectivity of these IAVs were monitored over approximately one year when held in five water types: (1) distilled water held in the lab at 4 ºC and (2–5) filtered surface water from each of four Alaska sites and maintained in the field at ambient temperature. By evaluating infectivity of IAVs in ovo following sample retrieval at four successive time points, we observed successive declines in IAV infectivity through time. Many viruses persisted for extended periods, as evidenced by ≥ 25% of IAVs remaining infectious in replicate samples for each treatment type through three sampling time points (144–155 days post-sample collection) and two viruses remaining viable in a single replicate sample each when tested upon collection at a fourth time point (361–377 days post-sample collection). The estimated probability of persistence of infectious IAVs in all five water types was estimated to be between 0.25–0.75 during days 50–200 post-sample collection as inferred through Kaplan-Meier survival analysis. Our results provide evidence that IAVs may remain infectious for extended periods, up to or even exceeding one year, when maintained in surface waters under ambient temperatures. Therefore, wetlands may represent an important medium in which infectious IAVs may reside outside of a biotic reservoir.

A protocol for modelling generalised biological responses using latent variables in structural equation models

Released September 07, 2021 09:21 EST

2021, One Ecosystem (6)

James Grace, Magdalena Steiner

Gbenga Akomolafe, editor(s)

In this paper we consider the problem of how to quantitatively characterize the degree to which a study object exhibits a generalized response. By generalized response, we mean a multivariate response where numerous individual properties change in concerted fashion due to some internal integration. In latent variable structural equation modeling (LVSEM), we would typically approach this situation using a latent variable to represent a general property of interest (e.g., performance) and multiple observed indicator variables that reflect the specific features associated with that general property. While ecologists have used LVSEM in a number of cases, there is substantial potential for its wider application. One obstacle is that LV models can be complex and easily over-specified, degrading their value as a means of generalization. It can also be challenging to diagnose causes of misspecification and understand which model modifications are sensible. In this paper we present a protocol, consisting of a series of questions, designed to guide the researchers through the evaluation process. These questions address (1) theoretical development, (2) data requirements, (3) whether responses to perturbation are general, (4) unique reactions by individual measures, and (5) how far generality can be extended. For this illustration, we reference a recent study considering the potential consequences of maintaining biodiversity as part of agricultural management on the overall quality of grapes used for wine making. We extend our presentation to include the complexities that occur when there are multiple species with unique reactions.

Instrumental variable methods in structural equation models

Released September 07, 2021 09:12 EST

2021, Methods in Ecology and Evolution (12) 1148-1157

James Grace

Michael Morrissey, editor(s)

  1. Instrumental variable regression (RegIV) provides a means for detecting and correcting parameter bias in causal models. Widely used in economics, recently several papers have highlighted its potential utility for ecological applications. Little attention has thus far been paid to the fact that IV methods can also be implemented within structural equation models (SEMIV). In this paper I present the motivations, requirements and basic procedures for using SEMIV.
  2. I first consider causal inference and IVs from the perspective of a randomized experiment with partial control of the cause of interest. I consider common sources of bias, the role of randomization and limits to its capacity to exclude bias. Sources of bias include omitted confounders, reciprocal causation, reverse causation and measurement error, all of which can all be seen as a single problem—endogeneity. The approach to estimating IV models most commonly used in econometric practice, two-stage least squares regression (2SLS), is explained, followed by a brief exposition of the covariance modelling approach used in SEM. Using data from an ecological field experiment, I illustrate the use of the treatment variable as an IV and then illustrate procedures for evaluating candidate variables that might serve as additional IVs.
  3. IV methods are shown to be useful for both detecting endogeneity and removing its influences. I illustrate some of the ways that bias can be generated, as well as diagnostic capabilities and means for remedy embedded within SEM. Procedures for screening and evaluating additional IVs reveal valuable lessons regarding the theoretical requirements and empirical standards for IVs.
  4. SEMIV provides a useful way to detect and control for bias. I suggest that the use of IVs within the SEM framework can support the simultaneous pursuit of causal inference and explanatory modelling, a common pair of aspirations for ecologists. Moving forward, there is a need for a better understanding of the capabilities of SEMIV and requirements for successful application.

Global biotic events evident in the Paleogene marine strata of the eastern San Francisco Bay area, California

Released September 07, 2021 07:51 EST

2021, Geological Society of America Memoir 229-268

Kristin McDougall-Reid

Paleogene marine strata in the eastern San Francisco Bay area are exposed in discontinuous outcrops in the various tectonic blocks. Although there are many missing intervals, the strata were previously thought to span most of the Paleocene and Eocene. Revision of biochronology and calibration to the international time scale as well as to the global oxygen isotope curve and sea-level curves indicate that the strata are latest Paleocene through middle Eocene in age and contain faunal changes that are linked to the overall global climate trends and hyperthermals of that time. The Paleocene-Eocene thermal maximum, third Eocene thermal maximum, early Eocene climatic optimum, and middle Eocene climatic optimum are all identified in the eastern San Francisco Bay marine strata. The dominance of smoothly finished, dissolution-resistant agglutinated benthic foraminiferal species corresponds with a rapid shoaling and rapid deepening (overcorrection) of the calcium compensation depth associated with the Paleocene-Eocene thermal maximum. The benthic foraminiferal extinction event was a dramatic turnover of benthic foraminiferal species that occurred shortly after the onset of the Paleocene-Eocene thermal maximum. Opportunistic species such as Bulimina, which indicate environmental stress and lower oxygen conditions, are commonly associated with the Paleocene-Eocene thermal maximum. Environmental changes similar to those observed during the Paleocene-Eocene thermal maximum also characterize the third Eocene thermal maximum, based on the agglutinated and opportunistic species. The early Eocene climatic optimum is noted by the presence of foraminiferal assemblages that indicate a stable, warmer water mass, abundant food, and an influx of terrigenous material. The onset and end of the middle Eocene climatic optimum are recognized by the dominance of siliceous microfossils. This research updates the age and environmental interpretations of the Paleogene formations occurring in the vicinity of Mount Diablo, eastern San Francisco Bay area. The revised interpretations, which are based on foraminifers and calcareous nannoplankton, make it possible to identify various global climatic and biotic events.

Virginia and Landsat

Released September 07, 2021 06:37 EST

2021, Fact Sheet 2021-3050

U.S. Geological Survey

From the shores of Jamestown and spreading north, south, and west, the lands that became the State of Virginia were some of the first in North America top experience rapid landscape change from European settlement. Imagery and data from the USGS Landsat series of satellites offer an unparalleled resource for the study, understanding, and preservation of Virginia’s land and water resources. From monitoring the health of water bodies to managing invasive species to planning for a range of climate change impacts, the USGS National Land Imaging (NLI) Program’s stewardship and public delivery of Landsat data has benefitted Virginians in myriad ways.

How to increase the supply of native seed to improve restoration success: The US native seed development process

Released September 06, 2021 09:10 EST

2021, Restoration Ecology

Molly Lutisha Mccormick, Amanda N. Carr, Robert Massatti, Daniel E. Winkler, Patricia De Angelis, Peggy Olwell

With the United Nations Decade on Ecosystem Restoration, restoration of damaged ecosystems is turning into a global movement. Restoration actions that are not based on science and an understanding of ecosystem function can thwart desired restoration outcomes at best and cause further damage to ecosystems at worst. Restoration often includes revegetation using seed. Where we source seed for restoration can make a difference for species establishment, restoration outcomes, and recovery of ecosystem function. However, sourcing seeds of native species, let alone genetically appropriate seed, is not currently possible for many restoration projects. The process of increasing and sourcing suitable seed for restoration includes many steps that need to be addressed typically years before a restoration project is initiated. These steps of seed collection, evaluation and development, field establishment, production, certification and procurement, storage, and finally restoration, need to be considered ideally at a scale larger than individual restoration projects and with research conducted in each step. We describe these steps as implemented in the United States, the challenges therein, and provide suggestions and examples of how groups can make efficient and effective progress toward getting the right seed in the right place at the right time.

Contemporary and historic dynamics of lake whitefish (Coregonus clupeaformis) eggs, larvae, and juveniles suggest recruitment bottleneck during first growing season

Released September 06, 2021 07:49 EST

2021, Annales Zoologici Finnici (58) 161-175

Z. Amidon, R. DeBruyne, Edward F. Roseman, Christine Mayer

To determine if a survival bottleneck occurs in Lake Erie's lake whitefish (Coregonus clupeaformis) population and explore possible mechanisms responsible, we examined contemporary and historical dynamics of lake whitefish eggs, larvae and juveniles. Widespread spawning and low overwinter egg retention were observed in 2016–2018, however subsequent larval CPUE remained consistent with historical observations when regular recruitment occurred. Highest larval CPUE was consistently observed in nearshore areas 3–11 km from mid-lake spawning locations. Fall age-1 juvenile presence was predicted by fall age-0 catches, indicating the bottleneck occurs during the first growing season. Our results suggest the following: (1) factors limiting recruitment affect survival during or after the pelagic larval stage to fall age-0, and (2) physical and biological processes underlying connectivity between spawning and nearshore nursery habitats may be limiting recruitment. Future research focusing on larval nursery habitat characterization and lake whitefish growth and survival may reveal mechanisms affecting recruitment.

Extreme precipitation and flooding contribute to sudden vegetation dieback in a coastal salt marsh

Released September 05, 2021 07:17 EST

2021, Plants Today (10)

Camille Stagg, Michael Osland, Jena A. Moon, Laura Feher, Claudia Laurenzano, Tiffany C. Lane, William Jones, Stephen Hartley

Climate extremes are becoming more frequent with global climate change and have the potential to cause major ecological regime shifts. Along the northern Gulf of Mexico, a coastal wetland in Texas suffered sudden vegetation dieback following an extreme precipitation and flooding event associated with Hurricane Harvey in 2017. Historical salt marsh dieback events have been linked to climate extremes, such as extreme drought. However, to our knowledge, this is the first example of extreme precipitation and flooding leading to mass mortality of the salt marsh foundation species, Spartina alterniflora. Here, we investigated the relationships between baseline climate conditions, extreme climate conditions, and large-scale plant mortality to provide an indicator of ecosystem vulnerability to extreme precipitation events. We identified plant zonal boundaries along an elevation gradient with plant species tolerant of hypersaline conditions, including succulents and graminoids, at higher elevations, and flood-tolerant species, including S. alterniflora, at lower elevations. We quantified a flooding threshold for wetland collapse under baseline conditions characterized by incremental increases in flooding (i.e., sea level rise). We proposed that the sudden widespread dieback of S. alterniflora following Hurricane Harvey was the result of extreme precipitation and flooding that exceeded this threshold for S. alterniflora survival. Indeed, S. alterniflora dieback occurred at elevations above the wetland collapse threshold, illustrating a heightened vulnerability to flooding that could not be predicted from baseline climate conditions. Moreover, the spatial pattern of vegetation dieback indicated that underlying stressors may have also increased susceptibility to dieback in some S. alterniflora marshes.Collectively, our results highlight a new mechanism of sudden vegetation dieback in S. alterniflora marshes that is triggered by extreme precipitation and flooding. Furthermore, this work emphasizes the importance of considering interactions between multiple abiotic and biotic stressors that can lead to shifts in tolerance thresholds and incorporating climate extremes into climate vulnerability assessments to accurately characterize future climate threats.

Demographic modeling informs functional connectivity and management interventions in Graham’s beardtongue

Released September 04, 2021 08:08 EST

2021, Conservation Genetics

Matthew Richard Jones, Daniel E. Winkler, Robert Massatti

Functional connectivity (i.e., the movement of individuals across a landscape) is essential for the maintenance of genetic variation and persistence of rare species. However, illuminating the processes influencing functional connectivity and ultimately translating this knowledge into management practice remains a fundamental challenge. Here, we combine various population structure analyses with pairwise, population-specific demographic modeling to investigate historical functional connectivity in Graham’s beardtongue (Penstemon grahamii), a rare plant narrowly distributed across a dryland region of the western US. While principal component and population structure analyses indicated an isolation-by-distance pattern of differentiation across the species’ range, spatial inferences of effective migration exposed an abrupt shift in population ancestry near the range center. To understand these seemingly conflicting patterns, we tested various models of historical gene flow and found evidence for recent admixture (~ 3400 generations ago) between populations near the range center. This historical perspective reconciles population structure patterns and suggests management efforts should focus on maintaining connectivity between these previously isolated lineages to promote the ongoing transfer of genetic variation. Beyond providing species-specific knowledge to inform management options, our study highlights how understanding demographic history may be critical to guide conservation efforts when interpreting population genetic patterns and inferring functional connectivity.

Machine learning predictions of mean ages of shallow well samples in the Great Lakes Basin, USA

Released September 04, 2021 07:47 EST

2021, Journal of Hydrology (603)

Christopher Green, Katherine Marie Ransom, Bernard T. Nolan, Lixia Liao, Thomas Harter

The travel time or “age” of groundwater affects catchment responses to hydrologic changes, geochemical reactions, and time lags between management actions and responses at down-gradient streams and wells. Use of atmospheric tracers has facilitated the characterization of groundwater ages, but most wells lack such measurements. This study applied machine learning to predict ages in wells across a large region around the Great Lakes Basin using well, chemistry, and landscape characteristics. For a dataset of age tracers in 961 samples, the travel time from the land surface to the sample location was estimated for each sample using parametric functions. The mean travel times were then modeled using a gradient boosting machine (GBM) algorithm with cross validation tuning of model metaparameters. The GBM approach was able to closely match estimated ages for the training data (RMSE = 0.26 natural-log scale years) and provided a reasonable match to testing data (RMSE = 0.84). Of the variables tested, well characteristics (e.g. depth), land use, hydrologic indicators (e.g. topographic wetness index), and water chemistry (e.g. nitrate, fluoride, and pH), substantially affected the predictions of age. GBM prediction was applied to 14,335 groundwater samples with median sample depth of 5.4 m, indicating for the Great Lakes Basin a broad distribution of ages among wells with a median of 32.9 years. Lag times of decades are likely for these wells to respond to changing solute fluxes near land surface. While depth variables most strongly affected predicted mean ages, chemical constituents exhibited smooth trends with age, consistent with prevailing conceptual models of evolving sources and geochemistry flowpaths. The results provide proof of concept for use of readily available variables of well, landscape, and chemical characteristics to improve groundwater age estimates across large regions.

Simulated effects of sea-level rise on the shallow, fresh groundwater system of Assateague Island, Maryland and Virginia

Released September 03, 2021 11:20 EST

2021, Scientific Investigations Report 2020-5104

Brandon J. Fleming, Jeff P. Raffensperger, Phillip J. Goodling, John P. Masterson

The U.S. Geological Survey, in cooperation with the National Park Service, developed a three-dimensional groundwater-flow model for Assateague Island in eastern Maryland and Virginia to assess the effects of sea-level rise on the groundwater system. Sea-level rise is expected to increase the altitude of the water table in barrier island aquifer systems, possibly leading to adverse effects to ecosystems on the barrier islands. The potential effects of sea-level rise were evaluated by simulating groundwater conditions under sea-level-rise scenarios of 20 centimeters (cm), 40 cm, and 60 cm. Results show that as sea level rises, low-lying areas of the island originally represented as receiving freshwater recharge in the baseline scenario are inundated by saltwater. This change from freshwater recharge to saltwater decreases the overall amount of freshwater recharging the system. As the water table rises in response to the higher sea levels, freshwater flow out of the system changes, with more freshwater leaving as submarine groundwater discharge and less freshwater leaving as seeps and evapotranspiration. At the current land-surface altitude, as much as 50 percent of the island may be inundated with a 60-cm rise in sea level, and the low-lying marshes may change from freshwater to saltwater.

Groundwater levels at 32 wells were monitored for as long as 12 months between October 2014 and September 2015 on Assateague Island. Results from objective classification analysis of 14 shallow monitoring wells show two dominant processes affecting groundwater levels in two different settings on the island. On the western side of the island, between the primary dune and the inland bays, water levels clearly respond to precipitation events. This side of the island is more protected from ocean tides and typically is more vegetated than the eastern side. On the eastern side of the island, between the Atlantic Ocean and the primary dune, water levels clearly respond to tidal events. Specific conductance was measured at four wells, two on the western part of the island and two on the eastern part of the island. Specific conductance values in the two wells west of the primary dune show episodic decreases, coinciding with precipitation events. Specific conductance values in the two wells on the eastern side of the primary dune show episodic increases, coinciding with high-tide events. These high frequency monitoring data are intended to aid in designing a monitoring network that can document both short-term and long-term hydrologic processes on Assateague Island National Seashore.

This study uses a modeling approach consistent with models developed for Gateway National Recreation Area, Sandy Hook Unit (New Jersey) and Fire Island National Seashore (New York). Combined, these models are meant to improve the regional capabilities for predicting climate-change effects on barrier islands and provide resource managers with a common set of tools for adaptation and mitigation of potentially adverse effects of sea-level rise.

Growth of greater white-fronted goose goslings relates to population dynamics at multiple scales

Released September 03, 2021 10:15 EST

2021, Journal of Wildlife Management

Thomas F Fondell, Brandt W. Meixell, Paul L. Flint

The abundance of greater white-fronted geese (Anser albifrons frontalis) on the Arctic Coastal Plain (ACP) of northern Alaska, USA, has more than tripled since the late 1990s; however, recent rate of annual population growth has declined as population size increased, which may indicate white-fronted geese on the ACP are approaching carrying capacity. We examined rates of gosling growth in greater white-fronted geese at 3 sites on the ACP during 2012–2014 to assist with predictions of future population trends and assess evidence for density-dependent constraints on recruitment. We marked goslings at hatch with individually coded webtags and conducted brood drives during early August to capture, measure, and weigh goslings. Annual estimates of gosling mass at 32 days old (range = 1,190–1,685) indicate that goslings had obtained >60% of asymptotic size. This rate of growth corresponds with that of other goose species and populations with access to high-quality forage and no limitations on forage availability, and is consistent with the overall increase in abundance of white-fronted geese at the ACP scale. Contrary to most previous investigations, age-adjusted mass of goslings did not decline with hatch date. Goslings grew faster in coastal areas than at inland freshwater sites. Taken together, these findings suggest forage was not limiting gosling growth rates in either ecosystem, but forage was of greater quality in coastal areas where goose foraging habitat is expanding because of permafrost subsidence. Spatial patterns of gosling growth corresponded with local-scale patterns of population density and population change; the areas with greatest rates of gosling growth were those with the greatest population density and rates of population increase. We found little evidence to suggest forage during brood rearing was limiting population increase of white-fronted geese on the ACP. Factors responsible for the apparent slowing of ACP-wide population growth are likely those that occur in stages of the annual cycle outside of the breeding grounds. 

Gut microbiota associated with different sea lamprey (Petromyzon marinus) life stages

Released September 03, 2021 09:46 EST

2021, Frontiers in Microbiology (12)

Prince P Mathai, Muruleedhara Byappanahalli, Nicholas S. Johnson, Michael J. Sadowsky

Sea lamprey (SL; Petromyzon marinus), one of the oldest living vertebrates, have a complex metamorphic life cycle. Following hatching, SL transition into a microphagous, sediment burrowing larval stage, and after 2–10+ years, the larvae undergo a dramatic metamorphosis, transforming into parasitic juveniles that feed on blood and bodily fluids of fishes; adult lamprey cease feeding, spawn, and die. Since gut microbiota are critical for the overall health of all animals, we examined the microbiota associated with SLs in each life history stage. We show that there were significant differences in the gut bacterial communities associated with the larval, parasitic juvenile, and adult life stages. The transition from larval to the parasitic juvenile stage was marked with a significant shift in bacterial community structure and reduction in alpha diversity. The most abundant SL-associated phyla were Proteobacteria, Fusobacteria, Bacteroidetes, Verrucomicrobia, Actinobacteria, and Firmicutes, with their relative abundances varying among the stages. Moreover, while larval SL were enriched with unclassified Fusobacteriaceae, unclassified Verrucomicrobiales and Cetobacterium, members of the genera with fastidious nutritional requirements, such as StreptococcusHaemophilusCutibacteriumVeillonella, and Massilia, were three to four orders of magnitude greater in juveniles than in larvae. In contrast, adult SLs were enriched with AeromonasIodobacterShewanella, and Flavobacterium. Collectively, our findings show that bacterial communities in the SL gut are dramatically different among its life stages. Understanding how these communities change over time within and among SL life stages may shed more light on the role that these gut microbes play in host growth and fitness.

First documentation of long-distance travel by a Florida manatee to the Mexican Caribbean

Released September 03, 2021 07:20 EST

2021, Ethology, Ecology and Evolution

Nataly Castelblanco-Martínez, Anmari Álvarez-Alemán, Raul Torres, Amy L. Teague, Sheri Barton, Kari A Rood, Eric A Ramos, Antonio A. Mignucci-Giannoni

West Indian manatees (Trichechus manatus) are separated into two allopatric subspecies: the Florida manatee (T. m. latirostris) and the Antillean manatee (T. m. manatus). In the winter of 2020–2021, an adult manatee was sighted off the coast of Cancun, Quintana Roo, Mexico, in areas where Antillean manatees are not typically seen. The individual had distinct watercraft scars on its body, which were matched using photo-identification to a known male Florida manatee (PE424) that had been repeatedly photographed in Florida since 1998. This is the first record of a Florida manatee visiting the Mexican Caribbean. Previous reports of individuals from this subspecies in Cuba, combined with genetic evidence, suggest some level of connectivity among geographically separated manatee populations.

  • We present the first evidence of along-distance movement by amanatee from Florida to the Yucatan Peninsula (Quintana Roo, Mexican Caribbean).

  • This case, previous reports of Florida manatees in Cuba, and genetic evidence, suggest acertain degree of genetic mixture among the two subspecies.

Identifying climate-resistant vernal pools: Hydrologic refugia for amphibian reproduction under droughts and climate change

Released September 02, 2021 07:41 EST

2021, Ecohydrology

Jennifer M. Cartwright, Toni Lyn Morelli, Evan H. Campbell Grant

Vernal pools of the northeastern United States provide important breeding habitat for amphibians but may be sensitive to droughts and climate change. These seasonal wetlands typically fill by early spring and dry by mid-to-late summer. Because climate change may produce earlier and stronger growing-season evapotranspiration combined with increasing droughts and shifts in precipitation timing, management concerns include the possibility that some pools will increasingly become dry earlier in the year, potentially interfering with amphibian life-cycle completion. In this context, a subset of pools that continue to provide wetland habitat later into the year under relatively dry conditions might function as ecohydrologic refugia, potentially supporting species persistence even as summer conditions become warmer and droughts more frequent. We used approximately 3,000 field observations of inundation from 449 pools to train machine-learning models that predict the likelihood of pool inundation based on pool size, day of the year, climate conditions, short-term weather patterns, and soil, geologic, and landcover attributes. Models were then used to generate predictions of pool wetness across five seasonal time points, three short-term weather scenarios, and four sets of downscaled climate projections. Model outputs are available through a website allowing users to choose the inundation thresholds, time points, weather scenarios, and future climate projections most relevant to their management needs. Together with long-term monitoring of individual pools at the site scale, this regional-scale study can support amphibian conservation by helping to identify which pools may be most likely to function as ecohydrologic refugia from droughts and climate change.

Unexpected diversity of Endozoicomonas in deep-sea corals

Released September 02, 2021 07:09 EST

2021, Marine Ecology Progress Series (673) 1-15

Christina A. Kellogg, Zoe A. Pratte

ABSTRACT: The deep ocean hosts a large diversity of azooxanthellate cold-water corals whose associated microbiomes remain to be described. While the bacterial genus Endozoicomonas has been widely identified as a dominant associate of tropical and temperate corals, it has rarely been detected in deep-sea corals. Determining microbial baselines for these cold-water corals is a critical first step to understanding the ecosystem services their microbiomes contribute, while providing a benchmark against which to measure responses to environmental change or anthropogenic effects. Samples of Acanthogorgia aspera, A. spissa, Desmophyllum dianthus, and D. pertusum (Lophelia pertusa) were collected from western Atlantic sites off the US east coast and from the northeastern Gulf of Mexico. Microbiomes were characterized by 16S rRNA gene amplicon surveys. Although D. dianthus and D. pertusum have recently been combined into a single genus due to their genetic similarity, their microbiomes were significantly different. The Acanthogorgia spp. were collected from submarine canyons in different regions, but their microbiomes were extremely similar and dominated by Endozoicomonas. This is the first report of coral microbiomes dominated by Endozoicomonas occurring below 1000 m, at temperatures near 4°C. D. pertusum from 2 Atlantic sites were also dominated by distinct Endozoicomonas, unlike D. pertusum from other sites described in previous studies, including the Gulf of Mexico, the Mediterranean Sea and a Norwegian fjord.

Precipitation-runoff processes in the Merced River Basin, Central California, with prospects for streamflow predictability, water years 1952–2013

Released September 01, 2021 16:37 EST

2021, Scientific Investigations Report 2020-5150

Kathryn M. Koczot, John C. Risley, JoAnn M. Gronberg, John M. Donovan, Kelly R. McPherson

The U.S. Geological Survey, in cooperation with the California Department of Water Resources (DWR), has constructed a new spatially detailed Precipitation-Runoff Modeling System (PRMS) model for the Merced River Basin, California, which is a tributary of the San Joaquin River in California. Operated through an Object User Interface (OUI) with Ensemble Streamflow Prediction (ESP) and daily climate distribution preprocessing functionality, the model is calibrated primarily to simulate (and eventually, forecast) year-to-year variations of inflows to Lake McClure during the critical April–July snowmelt season. The model is intended to become part of a suite of methods used by DWR for estimating daily streamflow from the Merced River Basin, especially during the snowmelt season. This study describes the results of the application of an analysis tool that simulates responses to climate and land-use variations at a higher spatial resolution than previously available to DWR.

A geographic information system was used to delineate the model domain, that is, areas draining to a single outlet at U.S. Geological Survey streamflow-gaging station 11270900, Merced River below Merced Falls Dam, near Snell, CA (also known as California Data Exchange Center station MRC), and subdrainage areas, including four draining to internal gages used as calibration targets. Using this delineation, three contiguous subbasins were recognized and, along with the model domain and nested calibration targets, are the simulation units evaluated in this report.

An auto-calibration tool, LUCA (Let Us CAlibrate), was used for each calibration node, from headwaters to basin outlet, and then parameters were manually adjusted to complete the calibration. The main objective was to match April–July snowmelt seasonal discharge values of simulated streamflow to observed (measured or reconstructed) discharge values. Calibration or validation periods used site-specific streamflows—mostly from October 1, 1988, through September 30, 2013—but differed according to the period-of-record available for the measurements collected at internal gages or reconstructed flows for the single outlet.

The accuracy of the Merced PRMS streamflow simulations varied seasonally, as compared to observed values. Based on statistical results, the Merced PRMS model satisfactorily simulated snowmelt seasonal streamflows. April–July calibrations for all areas had small negative bias (not greater than 7 percent) and low relative error (less than 8 percent). Less satisfactory performance for other seasons was attributed to several factors: (1) high uncertainty in low or zero flows in summer and fall, (2) lack of accounting for basin withdrawals and anthropogenic water use, (3) unavailability and (or) inaccuracy of observed (measured) meteorological input data, and (4) uncertainty in reconstructed streamflow data.

With some additional refinement, the Merced PRMS model may be used for forecasting seasonal and longer-term streamflow variations; evaluating forecasted and past climate and land cover changes; providing water-resource managers with a consistent and documented method for estimating streamflow at ungaged sites within the basin; and aiding environmental studies, hydraulic design, water management, and water-quality projects in the Merced River Basin.

Occurrence, fate, and transport of aerially applied herbicides to control invasive buffelgrass within Saguaro National Park Rincon Mountain District, Arizona, 2015–18

Released September 01, 2021 13:30 EST

2021, Scientific Investigations Report 2021-5039

Nicholas V. Paretti, Kimberly R. Beisner, Bruce W. Gungle, Michael T. Meyer, Bethany K. Kunz, Edyth Hermosillo, Jay R. Cederberg, Justine P. Mayo

The spread of the invasive and fire-adapted buffelgrass (Cenchrus ciliaris L.) threatens desert ecosystems by competing for resources, increasing fuel loads, and creating wildfire connectivity. The Rincon Mountain District of Saguaro National Park addressed this natural resource threat with the use of glyphosate-based herbicides (GBHs). In 2010, the Rincon Mountain District initiated an aerial restoration plan to control dense buffelgrass patches in remote areas and implemented a trial project to evaluate the effects of aerial restoration techniques that included the helicopter application of GBHs. In 2014, more than 250 acres of buffelgrass in the Rincon Mountain District were treated with the aerial application of GBHs. This widespread aerial application of GBHs continued through 2018, but the potential transport and effects to aquatic ecosystems were unknown.

In 2015–18, the U.S. Geological Survey, in cooperation with the National Park Service, studied the occurrence, distribution, fate, and transport of glyphosate in surface water and sediments derived from areas that were treated during past and current aerial herbicide applications. Three watersheds, treated with different regimens of GBHs, were sampled for glyphosate and the primary metabolite of glyphosate, aminomethylphosphonic acid (AMPA), during various hydrologic flow conditions. Water and aquatic sediment were collected from three watersheds, each in a different stage of application during the U.S. Geological Survey study. The unnamed watershed above the Loma Verde Trailhead referred to by the National Park Service as “Loma Verde canyon” had received no aerial treatment since 2014, whereas the Box Canyon watershed was aerially treated every year beginning in 2014. The Madrona Canyon watershed was first sprayed in 2016 and aerial application continued once a year though the entirety of the study. In addition, terrestrial soil samples were sampled from areas sprayed to understand dissipation rates and herbicide transport via sediments washing away during rainfall runoff. The concentrations present in water and sediment samples were compared to ecological benchmarks and characterized within the context of the environmental conditions of the park setting.

Of the 48 water samples collected and analyzed for glyphosate and AMPA, 10.4 percent and 14.6 percent were detected above the laboratory minimum detection limit, respectively. Mean water concentrations, calculated using specific statistical methods for non-detects, were equal to the laboratory minimum detection limit of 0.02 microgram per liter for samples collected in all the watersheds. In aquatic sediments, glyphosate and AMPA were detected in 10.7 and 25.0 percent of the samples, whereas 89.5 and 100 percent of the terrestrial soil samples had detections for glyphosate and AMPA, respectively. Mean aquatic sediment concentrations were 1.13 and 4.42 micrograms per kilogram (μg/kg) for glyphosate and AMPA, respectively. Mean terrestrial soil concentrations were orders of magnitude greater than water and aquatic sediment with concentrations of 678 μg/kg for AMPA and 1,240 μg/kg for glyphosate. Hours after glyphosate-based herbicide was applied, the concentrations of glyphosate and AMPA were present in terrestrial soil samples near or above the laboratory maximum detection limit of 5,000 μg/kg. The Box Canyon watershed was the most intensively treated watershed in terms of total land area treated, total amount of GBH applied, and number of years treated. The frequent and large volume of treatment resulted in the highest number of detections of glyphosate and AMPA in water (3 and 7 detections, respectively) and in aquatic sediment (2 and 6 detections, respectively) samples. In comparison, the other two watersheds had two or fewer detections for glyphosate and AMPA in water and aquatic sediment.

Glyphosate detected in pools was associated with increased rainfall closer in time to the last herbicide treatment. Glyphosate and AMPA concentration ratios above one, along with stable-isotope and tritium results, indicated that runoff processes were the primary transport mechanism for the two compounds when found in streams and pools rather than subsurface recharge or deeper flow paths. One pool in a small tributary of Box Canyon consistently had detections of glyphosate and AMPA in aquatic sediments, but these frequent concentrations were likely related to the intensive application upstream, near the steep terrain above the head of the channel that supplies the downstream pool. Intense flows during summer rainfall events move treated sediments into this channel where vegetation and the incised bedrock banks of the pool retained those sediments and ultimately led to frequent detections of both compounds. Isotope results in most of the pools and tinajas indicated that the water source had residence time representative of recently recharged waters, on the order of years.

No water concentrations exceeded published criteria for human health or aquatic life. Median and maximum glyphosate and AMPA water concentrations were lower than those reported in other national assessments, but maximum concentrations observed in individual runoff samples were higher than median concentrations measured in the national assessments. A similar finding was observed with aquatic sediment concentrations measured in the Rincon Mountain District. Results from the study were compared and assessed in the context of other studies examining GBHs and their effects on amphibians, fish, and macroinvertebrates. This comparison was used to generalize the potential risk to aquatic species similar to those species in the Rincon Mountain District. Concentrations of published effect levels were several orders of magnitude greater than the highest concentration detected in water at the Rincon Mountain District. Most published studies evaluate acute and chronic toxicity for glyphosate and GBHs, and these criteria may not be representative of environmental conditions in the Rincon Mountain District. The classic lethal dose studies conducted in a controlled laboratory setting may not be suitable for comparison to the longer, variable, low-dose exposure conditions in the pools and tinajas in the Rincon Mountain District. However, this study determined that the fate of GBHs transported from treated areas to potential aquatic habitat was highly variable in occurrence, timing, and concentrations. This variability in glyphosate concentrations was too high, and the potential exposure was determined to be far too complex to directly compare with the results from controlled studies.

This study provides the first information collected on GBHs used to control invasive buffelgrass in a remote, mountainous, and semiarid setting. The information about the transport and fate of herbicide application near aquatic habitat will help to inform managers about the broader ecosystem implications and provide useful information to other agencies implementing buffelgrass remediation strategies near aquatic habitat.

Redefining the age of the lower Colorado River, southwestern United States: Reply

Released September 01, 2021 09:13 EST

2021, Geology (49) e532-e533

Ryan S. Crow, Jonathan Schwing, Karl Karlstrom, Matt Heizler, Philip Pearthree, Kyle House, Shannon Dulin, Susane Janecke, Mark E. Stelten, Laurie Crossey

Crow et al. (2021) report new geochronologic and paleomagnetic data indicating that the lower Colorado River (CR) became integrated to the proto–Gulf of California (GOC) between 4.8 and 4.62 Ma instead of at ca. 5.3 Ma, as suggested by Dorsey et al. (2007, 2018). Dorsey et al. (2021) dispute this new chronology but offer no alternative explanation for one of the key data sets requiring it, new detrital sanidine (DS) geochronology. This accurate and precise constraint agrees with detrital zircon results on separate samples (Cloos, 2014) and is tied through magnetostratigraphy to the first known CR sands in the GOC.

Critical aquifer overdraft accelerates degradation of groundwater quality in California’s Central Valley during drought

Released September 01, 2021 08:01 EST

2021, Geophysical Research Letters (48)

Zeno Levy, Bryant Jurgens, Karen R. Burow, Stefan Voss, Kirsten Faulkner, Jose Alfredo Arroyo-Lopez, Miranda S. Fram

Drought-induced pumpage has precipitated dramatic groundwater-level declines in California’s Central Valley over the past 30 years, but the impacts of aquifer overdraft on water quality are poorly understood. This study coupled over 160,000 measurements of nitrate from ∼6,000 public-supply wells with a 30-year reconstruction of groundwater levels throughout the Central Valley to evaluate dynamic relations between aquifer exploitation and resource quality. We find that long-term rates of groundwater-level decline and water-quality degradation in critically overdrafted basins accelerate by respective factors of 2–3 and 3–5 during drought, followed by brief reversals during wetter periods. Episodic water-quality degradation can occur during drought where increased pumpage draws shallow, contaminated groundwater down to depth zones tapped by long-screened production wells. These data show, for the first time, a direct linkage between climate-mediated aquifer pumpage and groundwater quality on a regional scale.

Hydrate formation on marine seep bubbles and the implications for water column methane dissolution

Released September 01, 2021 07:25 EST

2021, Journal of Geophysical Research - Oceans (126)

Xiaojing Fu, William F. Waite, Carolyn D. Ruppel

Methane released from seafloor seeps contributes to a number of benthic, water column, and atmospheric processes. At seafloor seeps within the methane hydrate stability zone, crystalline gas hydrate shells can form on methane bubbles while the bubbles are still in contact with the seafloor or as the bubbles begin ascending through the water column. These shells reduce methane dissolution rates, allowing hydrate-coated bubbles to deliver methane to shallower depths in the water column than hydrate-free bubbles. Here, we analyze seafloor videos from six deepwater seep sites associated with a diverse range of bubble-release processes involving hydrate formation. Bubbles that grow rapidly are often hydrate-free when released from the seafloor. As bubble growth slows and seafloor residence time increases, a hydrate coating can form on the bubble's gas-water interface, fully coating most bubbles within ∼10 s of the onset of hydrate formation at the seafloor. This finding agrees with water-column observations that most bubbles become hydrate-coated after their initial ∼150 cm of rise, which takes about 10 s. Whether a bubble is coated or not at the seafloor affects how much methane a bubble contains and how quickly that methane dissolves during the bubble's rise through the water column. A simplified model shows that, after rising 150 cm above the seafloor, a bubble that grew a hydrate shell before releasing from the seafloor will have ∼5% more methane than a bubble of initial equal volume that did not grow a hydrate shell after it traveled to the same height.

Using regional watershed data to assess water-quality impairment in the Pacific Drainages of the United States

Released August 31, 2021 14:30 EST

2021, Scientific Investigations Report 2021-5087

Daniel R. Wise

Two datasets containing the first complete estimates of reach-scale nutrient, water use, dissolved oxygen, and pH conditions for the Pacific drainages of the United States were created to help inform water-quality management decisions in that region. The datasets were developed using easily obtainable watershed data, most of which have not been available until recently, and the techniques that were used provide a framework for integrating watershed data to assess water-quality impairment across other large hydrologic regions in the United States. These datasets were used to summarize regional nutrient and water-use conditions within impaired water bodies and to summarize regional dissolved oxygen concentrations and pH conditions for free-flowing stream reaches. Two examples are also presented that show how the datasets can be applied to specific water-quality management issues: (1) nutrient conditions in water bodies that have recently experienced problems with harmful algal blooms; and (2) dissolved oxygen and pH conditions in stream reaches likely to be populated by steelhead trout (Oncorhynchus mykiss irideus) during their summer run. The nutrient and water-use estimates could help inform actions aimed at managing water-quality conditions in impaired water bodies while the dissolved oxygen and pH predictions could be useful as screening tools to identify water bodies experiencing potential impairment.

Comparison of passive and pumped sampling methods for analysis of groundwater quality, Kirtland Air Force Base, Albuquerque, New Mexico, 2019

Released August 31, 2021 13:04 EST

2021, Scientific Investigations Report 2021-5074

Rebecca E. Travis, Kate Wilkins

A plume of ethylene dibromide (EDB) dissolved in groundwater extends northeast from the Bulk Fuels Facility on Kirtland Air Force Base, New Mexico. The leading edge of the EDB plume is upgradient from several water-supply wells. In 2013, the U.S. Geological Survey (USGS), in cooperation with the Albuquerque Bernalillo County Water Utility Authority and the U.S. Air Force, installed four sentinel well nests and two aquifer-test pumping wells between the EDB plume and the water-supply wells to serve as an early warning if the plume travels toward the water-supply wells. Since 2015, the USGS has used submersible pumps to sample the sentinel wells quarterly. In February 2017, the USGS began using dual-membrane passive diffusion bag samplers for quarterly sampling in the wells. To ensure that the passive samplers are obtaining representative samples of the groundwater contaminants, the USGS, in cooperation with the U.S. Air Force, initiated a study in 2019 to compare results from pump sampling and passive samplers and to use vertical profiling to determine the optimal depth for passive sampler placement in the screened interval to better inform long-term monitoring of the site.

Vertical profiling included deploying passive samplers throughout the submerged screened interval of four shallow sentinel wells. After retrieval of the passive samplers, pump samples were collected. The results of analyses of both types of samples were compared. Volatile organic compound results for this study were all below the raised reporting levels, which is a level five times the maximum concentration detected in a blank and determined by an in-depth quality assessment; therefore, this study focused on inorganic constituent results, including major ions, trace elements, and stable isotopes of water, to calculate the relative percent difference (RPD) between the pump and passive sampling method results as a way to determine where passive samplers would be best placed in each of the wells. Several analytes had an RPD of more than plus or minus 50 percent, and several analytes were not within the estimated variability for each sampling method. Additionally, the variability within each sampling method was quantified and compared. Factors that likely contributed to the lack of comparison between each sampling method included temporal variability, flow regime, volume of sample integrated through different aquifer intervals, and reduction/oxidation processes. RPD and method variability were used to determine the intervals within each well with the greatest agreement between sampling methods. Optimal sampling depths for each well were then correlated to the intervals where quarterly sampling has been occurring.

A river of change—The Rio Grande in the Big Bend region

Released August 31, 2021 12:56 EST

2021, Fact Sheet 2021-3036

David J. Dean

The Big Bend region is located within the heart of the Chihuahan Desert of North America. Within this region, the Rio Grande, referred to as the Rio Bravo in Mexico, is the international border between the United States and Mexico. The area known as the Big Bend is named after the large northerly bend that the river makes before flowing southeast to the Gulf of Mexico. This region is environmentally protected by both countries. Although large binational conservation efforts exist, the physical and ecological characteristics of the river have been substantially altered. Changes in Rio Grande hydrology (the seasonality, magnitude, duration, and variability in streamflow) have resulted in the widespread physical transformation of the river, resulting in the loss of important habitat for native and endangered fish and increased flood risk. U.S. Geological Survey (USGS) scientists, in cooperation with many other government agencies, universities, and non-governmental organizations (NGOs), are working to better understand these changes to inform management of the Rio Grande.

Monitoring native, resident nonsalmonids for the incidence of gas bubble trauma downstream of Snake and Columbia River Dams, 2021

Released August 31, 2021 08:44 EST

2021, Report

Kenneth Tiffan, Collin Smith, Nicole Joy Eller, Joe J. Warren

In 2020, a new spill program was implemented to aid the downstream passage of juvenile salmonids at mainstem dams on the Snake and Columbia rivers. Under this program, the total dissolved gas (TDG) cap was increased to 125% and monitoring of native, resident nonsalmonid (NRN) fishes for gas bubble trauma (GBT) became a requirement. The primary objective of this work was to measure the incidence and severity of GBT in NRN fishes resulting from increased juvenile fish passage spill and associated levels of TDG during the spring spill period. A secondary objective was to measure the incidence of GBT in incidentally collected juvenile salmonids when NRN sample size targets were met. NRN fishes were collected downstream from Bonneville, McNary, and Ice Harbor dams and examined for the incidence and severity of GBT in 2021. Fish were collected at each location weekly (6 April to 17 June) during the spring spill period by backpack electrofishing and beach seining. Washington and Oregon state water quality agencies established minimum and target sample sizes for monitoring, and in all weeks the minimum sample size of 50 fish was met and in most weeks the target sample size of 100 fish was met. Collected fish were examined for GBT according to the criteria and protocol established for the regional smolt monitoring program (SMP). Overall, GBT incidence and severity rankings were low and did not exceed the thresholds that would have triggered changes to the spill program. Using SMP criteria, weekly GBT incidences ranged from 0 to 1.0% downstream from Bonneville Dam, 0 to 6.2% downstream from McNary Dam, and 0 to 1.9% downstream from Ice Harbor Dam. Except for one three-spined stickleback (Gasterosteus aculeatus) collected downstream of Bonneville Dam, the only NRN species that showed signs of GBT was sculpin spp. GBT was observed in sculpin in body locations other than the unpaired fins and eyes (i.e., SMP criteria). If GBT incidence in all areas on the fish (i.e., paired fins, unpaired fins, eyes, body) are combined, then weekly GBT incidence rates increase and range from 0 to 4.3% downstream from Bonneville Dam, 0 to 15.4% downstream from McNary Dam, and 0 to 4.7% downstream from Ice Harbor Dam. This illustrates the effect of using different criteria to determine the incidence of GBT in NRN fishes. It also shows how the proportion of a species in a sample that is more prone to show GBT can influence GBT incidence rate. On a number of occasions, incidental catch of subyearling fall Chinook salmon were examined for GBT downstream of Bonneville Dam but none showed any signs. The DG was generally below 120% and never reached the 125% gas cap during the spring spill season, which may be why GBT incidence rates were so low as past research has shown that GBT signs in NRN fishes are relatively low below this TDG level.

Phytoplankton and cyanobacteria abundances in mid-21st century lakes depend strongly on future land use and climate projections

Released August 31, 2021 07:54 EST

2021, Global Change Biology

Karan Kakouei, B.M. Kraemer, O. Anneville, L. Carvalho, H. Feuchtmayr, Jennifer L. Graham, S. Higgins, F. Pomati, L.G. Rudstam, J.D. Stockwell, S.J. Thackeray, M. Vanni, R. Adrian

Land use and climate change are anticipated to affect phytoplankton of lakes worldwide. The effects will depend on the magnitude of projected land use and climate changes and lake sensitivity to these factors. We used random forests fit with long-term (1971–2016) phytoplankton and cyanobacteria abundance time series, climate observations (1971–2016), and upstream catchment land use (global Clumondo models for the year 2000) data from 14 European and 15 North American lakes basins. We projected future phytoplankton and cyanobacteria abundance in the 29 focal lake basins and 1567 lakes across focal regions based on three land use (sustainability, middle of the road, and regional rivalry) and two climate (RCP 2.6 and 8.5) scenarios to mid-21st century. On average, lakes are expected to have higher phytoplankton and cyanobacteria due to increases in both urban land use and temperature, and decreases in forest habitat. However, the relative importance of land use and climate effects varied substantially among regions and lakes. Accounting for land use and climate changes in a combined way based on extensive data allowed us to identify urbanization as the major driver of phytoplankton development in lakes located in urban areas, and climate as major driver in lakes located in remote areas where past and future land use changes were minimal. For approximately one-third of the studied lakes, both drivers were relatively important. The results of this large scale study suggest the best approaches for mitigating the effects of human activity on lake phytoplankton and cyanobacteria will depend strongly on lake sensitivity to long-term change and the magnitude of projected land use and climate changes at a given location. Our quantitative analyses suggest local management measures should focus on retaining nutrients in urban landscapes to prevent nutrient pollution from exacerbating ongoing changes to lake ecosystems from climate change.

Watershed and estuarine controls both influence plant community and tree growth changes in tidal freshwater forested wetlands along two U.S. mid-Atlantic rivers

Released August 31, 2021 07:49 EST

2021, Forests (9)

Gregory B. Noe, Norman A Bourg, Ken Krauss, Jamie A. Duberstein, Cliff R. Hupp

The tidal freshwater zone near the estuarine head-of-tide is potentially sensitive to both sea-level rise and associated salinity increases as well as changing watershed inputs of freshwater and nutrients. We evaluated the vegetation response of tidal freshwater forested wetlands (TFFW) to changes in nontidal river versus estuarine controls along the longitudinal gradient of the Mattaponi and Pamunkey rivers in the Mid-Atlantic USA. The gradient included nontidal freshwater floodplain (NT) and upper tidal (UT), lower tidal (LT), and stressed tidal forest transitioning to marsh (ST) TFFW habitats on both rivers. Plot-based vegetation sampling and dendrochronology were employed to examine: (1) downriver shifts in plant community composition and the structure of canopy trees, understory trees/saplings/shrubs and herbs, tree basal-area increment (BAI) and (2) interannual variability in BAI from 2015 dating back as far as 1969 in relation to long-term river and estuary monitoring data. With greater tidal influence downstream, tree species dominance shifted, live basal area generally decreased, long-term mean BAI of individual trees decreased, woody stem mortality increased, and live herbaceous vegetative cover and richness increased. Acer rubrum, Fagus grandifolia, Ilex opaca, and Fraxinus pennsylvanica dominated NT and UT sites, with F. pennsylvanica and Nyssa sylvatica increasingly dominating at more downstream tidal sites. Annual tree BAI growth was positively affected by nontidal river flow at NT and UT sites which were closer to the head-of-tide, positively influenced by small salinity increases at LT and ST sites further downstream, and positively influenced by estuarine water level throughout the gradient; nutrient influence was site specific with both positive and negative influences. The counterintuitive finding of salinity increasing tree growth at sites with low BAI is likely due to either competitive growth release from neighboring tree death or enhanced soil nutrient availability that may temporarily mitigate the negative effects of low-level salinization and sea-level increases on living TFFW canopy trees, even as overall plant community conversion to tidal marsh progresses.

Predicting non-native insect impact: Focusing on the trees to see the forest

Released August 31, 2021 07:36 EST

2021, Biological Invasions

Ashley N. Schulz, Angela M. Mech, Matthew P. Ayres, Kamal J.K. Gandhi, Nathan P. Havill, Daniel A. Herms, Angela Marie Hoover, Ruth A. Hufbauer, Andrew M. Liebhold, Travis D. Marsico, Kenneth F. Raffa, Patrick C. Tobin, Daniel R. Uden, Kathryn A. Thomas

Non-native organisms have invaded novel ecosystems for centuries, yet we have only a limited understanding of why their impacts vary widely from minor to severe. Predicting the impact of non-established or newly detected species could help focus biosecurity measures on species with the highest potential to cause widespread damage. However, predictive models require an understanding of potential drivers of impact and the appropriate level at which these drivers should be evaluated. Here, we used non-native, specialist herbivorous insects of forest ecosystems to test which factors drive impact and if there were differences based on whether they used woody angiosperms or conifers as hosts. We identified convergent and divergent patterns between the two host types indicating fundamental similarities and differences in their interactions with non-native insects. Evolutionary divergence time between native and novel hosts was a significant driver of insect impact for both host types but was modulated by different factors in the two systems. Beetles in the subfamily Scolytinae posed the highest risk to woody angiosperms, and different host traits influenced impact of specialists on conifers and woody angiosperms. Tree wood density was a significant predictor of host impact for woody angiosperms with intermediate densities (0.5–0.6 mg/mm3) associated with highest risk, whereas risk of impact was highest for conifers that coupled shade tolerance with drought intolerance. These results underscore the importance of identifying the relevant levels of biological organization and ecological interactions needed to develop accurate risk models for species that may arrive in novel ecosystems.

Using ALOS-2 synthetic aperture radar (SAR) and interferometric SAR to detect landslides on the mountainous island of Pohnpei, Federated States of Micronesia

Released August 30, 2021 15:58 EST

2021, Open-File Report 2021-1084

Elijah W. Ramsey III, Amina Rangoonwala

This study was undertaken by the U.S. Geological Survey to assess the detectability of landslides in the densely forested and mountainous island of Pohnpei in the Federated States of Micronesia. The study used existing field-observed land-cover changes and landslides visible on Google Earth (GE) images. A limited number of ALOS-2 PALSAR-2 L-band synthetic aperture radar (SAR) images were collected on two adjacent orbit paths before and after an intense rainfall event that affected Pohnpei in mid-March 2018. Similar sets of images were collected in 2019 and 2020. Low coherence throughout the island interior eliminated use of phase-change products, and change analysis identified no landslide features as having formed in 2019 or 2020. The assessment of red-green-blue image composites and application of the log-ratio method to the 2018 ground-range SAR images identified 5 of the 11 landslides observed on the GE images. Visual comparisons of the co-event and post-event coherence image products detected 9 of the 11 landslides observed on the GE images. Combined, the ground-based SAR and interferometric SAR coherence change detections overcame high temporal and spatial decorrelations, identified all but one landslide visible in the GE comparison, and included substantial redundancy. The robustness of the landslide detection indicates that an increased collection frequency of L-band images could support systematic monitoring of land-cover change on Pohnpei at the scale reported in this study.

Behavior and survival of hatchery rainbow trout (Oncorhynchus mykiss) in the upper Cowlitz River Basin, Washington, 2013 and 2017

Released August 30, 2021 13:33 EST

2021, Open-File Report 2021-1085

Amy C. Hansen, Tobias J. Kock, Brian K. Ekstrom, Theresa L. Liedtke

A two-year study (2013 and 2017) was conducted to determine if annual releases of hatchery rainbow trout (resident Oncorhynchus mykiss) in the upper Cowlitz River Basin, Washington adversely affected anadromous fish in the basin. Rainbow trout tagged with radio transmitters were monitored after release to describe movement patterns, entrainment rates at Cowlitz Falls Dam, and survival. Additionally, trout that were radio-tagged in 2017 were monitored during spring 2018 to determine if any moved upstream and entered tributaries where winter steelhead (anadromous Oncorhynchus mykiss) spawning occurs. A total of 580 hatchery rainbow trout (122 in 2013 and 458 in 2017) were radio-tagged and released at three release sites: (1) Cowlitz Falls Campground on Cowlitz River Arm of Lake Scanewa river kilometer (rkm) 155, (2) Cispus River Arm of Lake Scanewa rkm 1, and (3) Day Use Park on Cowlitz River Arm of Lake Scanewa rkm 146. Most radio-tagged trout (70 percent) remained within 6.4 rkm of the release site but some fish moved at least 25.7 rkm from the release site. The predominant movement direction was downstream. More than twice as many fish released at Cowlitz Falls Campground in 2017 (compared to the other two release sites) remained in the Cowlitz River, where potential overlap with steelhead occurs. A total of 28.3 percent of the study fish were entrained at Cowlitz Falls Dam. Apparent survival (time until movement ceased) for most tagged trout was fewer than 100 days from release in both years and no fish were detected moving during the spring following their release. In summary, hatchery rainbow trout released upstream from Cowlitz Falls Dam seem to remain primarily in Lake Scanewa or entrained at Cowlitz Falls Dam with few fish surviving to winter months. We found no evidence of hatchery trout interacting with steelhead in spawning tributaries during spring months. These results suggest that trout stocking in the upper Cowlitz River Basin poses minimal threat to anadromous fish in the basin.

Historical hydrologic and geomorphic conditions on the Black River and selected tributaries, Arkansas and Missouri

Released August 30, 2021 13:01 EST

2021, Scientific Investigations Report 2021-5067

Jessica Z. LeRoy, Richard J. Huizinga, David C. Heimann, Evan M. Lindroth, Henry F. Doyle

The Black River flows through southeast Missouri and northeast Arkansas to its confluence with the White River in Arkansas. The U.S. Army Corps of Engineers operates Clearwater Dam on the Black River and a series of dams in the White River Basin primarily for flood control. In this study, the hydrology and geomorphology of the Black River are examined through an analysis of annual mean and peak discharges at streamgages, a specific stage analysis of stage and discharge at streamgages, and an examination of bathymetric data and aerial imagery. Five streamgages on the Black River were analyzed, in addition to four streamgages on Black River tributaries and one streamgage on the White River, located just downstream from the Black River confluence. The analyses indicated that regulation of discharges at the flood-control dams caused a decrease in the magnitude and variability of the peak discharges at several of the analyzed gages on the Black and White Rivers. Conversely, peak discharges on the Black River have been increasing since water year 2000, though this is not matched by an increase in peak discharges on the White River for the same time period. The specific stage analyses and the available morphologic data generally did not indicate pronounced changes in stage-discharge relations at streamgages on the Black River, with the exception of the gages nearest to Clearwater Dam.

Geohydrology and water quality of the stratified-drift aquifers in West Branch Cayuga Inlet and Fish Kill Valleys, Newfield, Tompkins County, New York

Released August 30, 2021 10:00 EST

2021, Scientific Investigations Report 2021-5064

Benjamin N. Fisher, Paul M. Heisig, William M. Kappel

From 2011 to 2016, the U.S. Geological Survey, in cooperation with the Town of Newfield and the Tompkins County Planning Department, performed a study of the stratified-drift aquifers in the West Branch Cayuga Inlet and Fish Kill Valleys in Newfield, Tompkins County, New York. Both confined and unconfined aquifers were identified, mostly in the valleys. The confined aquifer consists of a discontinuous sand and gravel layer that overlies bedrock and is commonly confined by overlying fine-grained sediments. The unconfined aquifer consists of surficial ice contact sand and gravel, alluvial silt, sand and gravel, and areas where several large tributary streams deposited alluvial fans in the valley, all of which were deposited during and after the last glacial recession.

The unconfined aquifers are primarily recharged by direct infiltration of precipitation at the land surface, by surface runoff and shallow subsurface flow from adjacent hillsides, and by seepage loss from streams crossing the aquifer, especially on alluvial fans. The confined aquifers are primarily recharged by groundwater stored in the overlying sand and gravel aquifer that slowly seeps downward through the underlying confining layer. Other sources of recharge are precipitation that falls directly on the surficial confining unit and adjacent valley walls, which then slowly seeps downward and enters the confined aquifer, and groundwater flow from bordering till and bedrock and from bedrock below the valley. There may also be some recharge where confining units are absent or where parts of the confining units contain sediments with moderate permeability.

The groundwater naturally discharges to the Fish Kill and West Branch Cayuga Inlet streams and to wetlands overlying the aquifer boundaries, with additional losses due to evapotranspiration. Groundwater is pumped from the aquifers by domestic, municipal, and agricultural wells. Approximately 57.9 million gallons per year was withdrawn from the stratified-drift (sand and gravel) aquifers.

Groundwater samples were collected from 11 wells, and surface water samples were collected at 2 sites, one each from Fish Kill and West Branch Cayuga Inlet. None of the common ions (for example, sodium, chloride, and magnesium) exceeded existing drinking water standards at either surface water site. The concentration of nitrate plus nitrite detected was 0.4 milligram per liter as nitrogen in the West Branch Cayuga Inlet site. Total phosphorus was detected at 0.01 milligram per liter as phosphate for both sites. Of the 11 wells sampled, 8 were finished in confined sand and gravel aquifers, 1 was finished in unconfined sand and gravel, and 2 were finished in shale bedrock. Groundwater quality in the study area generally met Federal and State drinking-water standards. However, of the 11 samples taken, 2 exceeded the U.S. Environmental Protection Agency drinking water advisory taste threshold of 20 milligrams per liter for sodium, 8 exceeded the secondary maximum contaminant level of 300 micrograms per liter for iron, and 9 exceeded the secondary maximum contaminant level of 50 micrograms per liter for manganese.

Early Pleistocene climate-induced erosion of the Alaska Range formed the Nenana Gravel

Released August 30, 2021 07:32 EST

2021, Geology

Rachel Sortor, Brent Goehring, Sean Bemis, Chester A. Ruleman, Marc Caffee, Dylan Ward

The Pliocene-Pleistocene transition resulted in extensive global cooling and glaciation, but isolating this climate signal within erosion and exhumation responses in tectonically active regimes can be difficult. The Nenana Gravel is a foreland basin deposit in the northern foothills of the Alaska Range (USA) that has long been linked to unroofing of the Alaska Range starting ca. 6 Ma. Using 26Al/10Be cosmogenic nuclide burial dating, we determined the timing of deposition of the Nenana Gravel and an overlying remnant of the first glacial advance into the northern foothills. Our results indicate that initial deposition of the Nenana Gravel occurred at the onset of the Pleistocene ca. 2.34 Ma and continued until at least ca. 1.7 Ma. The timing of initial deposition is correlative with expansion of the Cordilleran ice sheet, suggesting that the deposit formed due to increased glacial erosion in the Alaska Range. Abandonment of Nenana Gravel deposition occurred prior to the first glaciation extending into the northern foothills. This glaciation was hypothesized to have occurred ca. 1.5 Ma, but we found that it occurred ca. 0.39 Ma. A Pleistocene age for the Nenana Gravel and marine oxygen isotope stage 10 age for the oldest glaciation of the foothills necessitate reanalysis of incision and tectonic rates in the northern foothills of the Alaska Range, in addition to a shift in perspective on how these deposits fit into the climatic and tectonic history of the region.

Visitors count! Guidance for protected areas on the economic analysis of visitation

Released August 29, 2021 08:10 EST

2021, Book

Anna Spenceley, Jan Philipp Schagner, Barbara Engels, Catherine Cullinane Thomas, Mauel Engelbauer, Joel Erkkonen, Hubert Job, Liisa Kajala, Lisa Majewski, Daniel Metzler, Marius Mayer, Andrew Rylance, Manuel Woltering, Niklas Scheder, Cecile Smith-Christensen, Thiago Beraldo Souza

The value of protected areas is often hidden from direct view. Once managers understand the number and behaviour of visitors they host, and the revenues and costs they generate, informed decisions on management plans and tourism strategies can be made. Demonstrating the positive impact of protected areas on the local economy can lead to greater buy-in and ownership of conservation practices and places, less poaching and land encroachment, and may also help offset some of the human-wildlife conflict where it occurs. Drawing on case studies from around the world, Visitors Count! aims to build awareness, knowledge and capacity internationally on how to best undertake economic evaluations of tourism in protected areas, and thereby contribute towards a globally acknowledged standard methodology.

Taxonomic and functional differences between winter and summer crustacean zooplankton communities in lakes across a trophic gradient

Released August 28, 2021 07:10 EST

2021, Journal of Plankton Research

Kirill Shchapov, P. Wilburn, A. Bramburger, G. Silsbe, L. Olmanson, Christopher J. Crawford, E. Litchmann, T. Ozersky

Despite increasing interest in winter limnology, few studies have examined under-ice zooplankton communities and the factors shaping them in different types of temperate lakes. To better understand drivers of zooplankton community structure in winter and summer, we sampled 13 lakes across a large trophic status gradient for crustacean zooplankton abundance, taxonomic and functional community composition and C/N stable isotopes. Average winter zooplankton densities were one-third of summer densities across the study lakes. Proportionally, cladocerans were more abundant in summer than winter, with the opposite pattern for calanoids and cyclopoids. In green (eutrophic) lakes, zooplankton densities were higher under the ice than in brown (dystrophic) and blue (oligotrophic) lakes, suggesting better conditions for zooplankton in productive lakes during winter. Overall, zooplankton communities were more similar across lakes under the ice than during the open water season. Feeding group classification showed a decrease in herbivore abundance and an increase in predators from summer to winter. C/N stable isotope results suggested higher lipid content in overwintering zooplankton and potentially increased reliance on the microbial loop by winter zooplankton. Our results show substantial variation in the seasonality of zooplankton communities in different lake types and identify some of the factors responsible for this variation.

Water quality, instream habitat, and the distribution of suckers in the upper Lost River watershed of Oregon and California, summer 2018

Released August 27, 2021 10:32 EST

2021, Open-File Report 2021-1077

Barbara A. Martin, Summer M. Burdick, Stephen T. Staiger, Caylen M. Kelsey

Executive Summary

Endangered Lost River (Deltistes luxatus) and shortnose (Chasmistes brevirostris) suckers primarily use lotic habitats during the spring spawning season in the Upper Klamath Lake watershed. However, summer-time surveys of the upper Lost River watershed in 1972, 1975 and 1989–90 indicated that adults of both endangered species use tributaries of Clear Lake Reservoir (hereafter: Clear Lake) year-round. Adult shortnose suckers have also been documented to use tributaries of Gerber Reservoir year-round. We surveyed the tributaries of Clear Lake and Gerber Reservoir to provide up-to-date information on the timing, distribution, and habitat use within the upper Lost River drainage by these two endangered sucker species.

Contrary to previous studies, this study did not capture any Lost River suckers in the Clear Lake tributaries. Genetics samples from suckers collected during this study were used to verify that no Lost River suckers were captured. At the time of this study, genetics could not identify the differences between shortnose and the non-endangered Klamath largescale suckers (Catostomus snyderi), therefore, morphology was used to separate these two species. Furthermore, the shortnose suckers and the Klamath largescale suckers documented in the upper Lost River drainage are more similar to Klamath largescale suckers than shortnose suckers that exist in the Upper Klamath Lake recovery unit. Therefore, the suckers we documented during our surveys were most likely Klamath largescale suckers.

We captured suckers, age-0 to age-9, in the Clear Lake tributaries within stream pools and flooded meadows behind water retention structures. However, no suckers were collected in small reservoirs sampled upstream of Clear Lake. Suckers were found in habitats with mud and fine substrate at depths of 0.5–3.0 meters, with most captured at 1.0 meter or less. Suckers co-occurred with nonnative species, which were more abundant in our survey than in previous surveys in the tributaries to Clear Lake.

Gerber Reservoir tributaries yielded more suckers per unit effort than Clear Lake tributaries. All suckers captured in the tributaries of Gerber Reservoir were identified as Klamath Largescale suckers. The suckers in tributaries to Gerber Reservoir were collected in similar habitat as those in Clear Lake tributaries and were age-0 to age-6.

Evaluation of movement and survival of juvenile steelhead (Oncorhynchus mykiss) and coho salmon (Oncorhynchus kisutch) in the Klickitat River, Washington, 2018–2019

Released August 27, 2021 08:30 EST

2021, Open-File Report 2021-1083

Scott D. Evans, David S. Lindley, Tobias J. Kock, Amy C. Hansen, Russell W. Perry, Joseph S Zendt, Nicolas Romero

A 2-year telemetry study was conducted April–July in 2018 and 2019 to evaluate migration behavior and survival of juvenile steelhead (Oncorhynchus mykiss) and coho salmon (O. kisutch) in the Klickitat River, Washington. A total of 612 natural-origin steelhead, collected in a smolt trap on the Klickitat River, were tagged, released, and monitored as they outmigrated through the lower 17 kilometers (km) of the Klickitat River, and in the 52 km reach between the mouth of the Klickitat River and Bonneville Dam. The primary goal of the steelhead study was to estimate survival through the Klickitat River delta, the 2 km reach located at the confluence of the Klickitat and Columbia rivers. A total of 400 hatchery-origin coho salmon were tagged and released at the Klickitat Hatchery and monitored during migration through the lower 68 km of the Klickitat River and in the Columbia River to Bonneville Dam. The primary goals of the coho salmon study were (1) to estimate survival through the Klickitat River delta and (2) to determine residence time in the Klickitat River to assess potential for interactions with rearing natural-origin fish.

Many tagged steelhead and coho salmon moved quickly downstream and left the Klickitat River shortly after release. Median elapsed time from release to Klickitat River exit ranged from 1.4 to 1.5 days for steelhead, and from 5.1 to 12.9 days for coho salmon during the two-year study. Ten percent of the tagged coho salmon in 2018 remained in the Klickitat River for 21.9–29.2 days before entering the Columbia River. In 2019, ten percent of the tagged coho salmon remained in the Klickitat River for 36.0–45.5 days before entering the Columbia River. This suggests that some hatchery fish spend considerable time in the river after hatchery release. Migration rates were consistently slow for both species in the Klickitat River delta compared to upstream reaches of the free-flowing Klickitat River and downstream reaches of the Columbia River. Similarly, reach-specific survival was highest in free-flowing reaches of the Klickitat River and lowest near the Klickitat River delta. Cumulative survival from release to sites located downstream of the Klickitat River delta were 0.78 for juvenile steelhead in both 2018 and 2019, and 0.57 and 0.61 for juvenile coho salmon in 2018 and 2019. Standardized survival estimates (survival per 100 river kilometers) were 0.243 in 2018 and 0.302 in 2019 for steelhead, and 0.100 in 2018 and 0.153 in 2019 for coho salmon. These estimates of standardized survival are low compared to similar estimates from other rivers in Washington, Oregon, Idaho, and California. This study provided new information about survival and residence time of juvenile steelhead and coho salmon in the Klickitat River. Additional studies would be helpful to understand factors affecting outmigration survival and overlap between hatchery-origin and natural-original juvenile steelhead and coho salmon in the system.

Development of demographic models to analyze populations with multi-year data—Using Agassiz’s Desert Tortoise (Gopherus agassizii) as a case study

Released August 27, 2021 08:20 EST

2021, Open-File Report 2018-1094

Kristin H. Berry, Julie L. Yee

We developed a model for analyzing multi-year demographic data for long-lived animals and used data from a population of Agassiz’s desert tortoise (Gopherus agassizii) at the Desert Tortoise Research Natural Area in the western Mojave Desert of California as a case study. The study area was 7.77 square kilometers and included two locations: inside and outside the fenced boundary. The wildlife-permeable, protective fence was designed to prevent entry from vehicle users and sheep grazing. We collected mark-recapture data from 1,123 tortoises during seven annual surveys consisting of two censuses each over a 34-year period. Additional data were collected when marked tortoises were recovered dead and removed between survey years. We used a Bayesian modeling framework to develop a multistate Jolly-Seber model because of its ability to handle unobserved (latent) states and modified this model to incorporate the additional data from non-survey years. Three size-age states (juvenile, immature, adult), sex (female, male), two location states (inside and outside the fenced boundary), and three survival states (not-yet-entered, entered/alive, and dead/removed) were incorporated into the model. We calculated population densities and estimated probabilities of growth of the tortoises from one size-age state to a larger size-age state, survival after 1 year and 5 years, and detection. Our results show a declining population with low estimates for survival after 1 year and 5 years. The probability for tortoises to move from outside to inside the boundary fence was greater than for tortoises to move from inside the fence to outside. The probability for detecting tortoises differed by size-age state and was lowest for the smallest tortoises and highest for the adult tortoises. The framework for the model can be used to analyze other animal populations where vital rates are expected to vary depending on multiple individual states.

An efficient Bayesian framework for updating PAGER loss estimates

Released August 27, 2021 08:03 EST

2021, Earthquake Spectra Journal (36) 1719-1742

Hae Young Noh, Kishor Jaiswal, Davis (Contractor) T Engler, David J. Wald

We introduce a Bayesian framework for incorporating time-varying noisy reported data on damage and loss information to update near real-time loss estimates/alerts for the U.S. Geological Survey’s Prompt Assessment of Global Earthquakes for Response (PAGER) system. Initial loss estimation by PAGER immediately following an earthquake includes several uncertainties. Historically, the PAGER’s alerting on fatality and economic losses has not incorporated location-specific reported data on physical damage or casualties for a given earthquake. The proposed framework provides the ability to include early reports on fatalities at any given time and improve the overall impact forecast for the earthquake. The reported data on fatalities or damage are generally incomplete and noisy, especially in the early hours of the disaster. To address these challenges, we develop a recursive Bayesian updating framework that takes into account the loss projection model and the measurement and model uncertainties. The framework is applied to loss data for three example earthquakes, and the results show that the proposed updating improves the loss estimates and alert level to the correct level within the first day of the earthquake.

Michigan and Landsat

Released August 26, 2021 14:49 EST

2021, Fact Sheet 2021-3047

U.S. Geological Survey

Water means a lot to Michigan, often called the Great Lakes State. The name “Michigan” comes from an Ojibwe word meaning large, or great, water or lake. As the only State touching four of the five Great Lakes—Michigan, Superior, Huron, and Erie—it claims the longest freshwater coastline in the United States.

Yet Michigan is not just about water—forests, agriculture, mines, cities, and even sand dunes stretch across the State’s landscape. Much of what happens on the land does connect in some way with Michigan’s inland and coastal waters. Michigan relies on a healthy environment to support its residents, abundant tourists, and diverse species of wildlife that call the State and its surrounding waters home. From hundreds of miles above, Landsat satellites provide a clearer picture of the connections among land, water, and the people and wildlife that inhabit the State.

Pollinator communities vary with vegetation structure and time since management within regenerating timber harvests of the Central Appalachian Mountains

Released August 26, 2021 11:08 EST

2021, Forest Ecology and Management (495)

Codey L. Mathis, Darin J. McNeil Jr., Monica R. Lee, Christina M. Grozinger, David I. King, Clint R. V. Otto, Jeffery A. Larkin

Native pollinator populations across the United States are increasingly threatened by a multitude of ecological stressors. Although the drivers behind pollinator population declines are varied, habitat loss/degradation remains one of the most important threats. Forested landscapes, where the impacts of habitat loss/degradation are minimized, are known to support robust pollinator populations in eastern North America. Within heavily forested landscapes, timber management is already implemented as a means for improving forest health and enhancing wildlife habitat, however, little is known regarding the characteristics within regenerating timber harvests that affect forest pollinator populations. In 2018-19, we monitored insect pollinators in 143 regenerating (≤ 9 growing seasons post-harvest) timber harvest sites across Pennsylvania. During 1,129 survey events, we observed over 9,100 bees and butterflies, 220 blooming plant taxa, and collected over 2,200 pollinator specimens. Bee and butterfly abundance were positively associated with season-wide floral abundance and negatively associated with dense vegetation that inhibits the growth of understory floral resources. Particularly in late summer, few pollinators were observed in stands > 6 years post-harvest, with models predicting five times more bees in 1-year-old harvests than in 9-year-old harvests. Pollinator species diversity was positively associated with floral diversity and percent forb cover, and negatively associated with percent tall (>1m) sapling cover. These results suggest that regenerating timber harvests promote abundant and diverse pollinator communities in the Appalachian Mountains, though pollinator abundance declined quickly as woody stems regenerated. Ultimately, our findings contribute to a growing body of literature suggesting that dynamic forest management producing an even mix of age classes would benefit forest pollinator populations in the Central Appalachian Mountains.

Negligible evidence for detrimental effects of Leucocytozoon infections among Emperor Geese (Anser canagicus) breeding on the Yukon-Kuskokwim Delta, Alaska

Released August 26, 2021 10:40 EST

2021, International Journal for Parasitology: Parasites and Wildlife (16) 103-112

Andrew M. Ramey, Raymond Bucheit, Brian D. Uher-Koch, John Reed, M. Andreina Pacheco, Ananias Escalante, Joel Schmutz

Emperor Geese (Anser canagicus) are iconic waterfowl endemic to Alaska and adjacent areas of northeastern Russia that are considered to be near threatened by the International Union for Conservation. This species has been identified as harboring diverse viruses and parasites which have, at times, been associated with disease in other avian taxa. To better assess if disease represents a vulnerability for Emperor Geese breeding on the Yukon-Kuskokwim Delta, Alaska, we evaluated if haemosporidian parasites were associated with decreased mass or survival among adult female nesting birds captured during 2006–2016. Through molecular analyses, we detected genetically diverse LeucocytozoonHaemoproteus, and Plasmodium parasites in 28%, 1%, and 1% of 607 blood samples screened in triplicate, respectively. Using regression analysis, we found evidence for a small effect of Leucocytozoon infection on the mass of incubating adult female Emperor Geese. The estimated mass of infected individuals was approximately 43 g (95% CI: 20–67 g), or approximately 2%, less than uninfected birds when captured during the second half of incubation (days 11–25). We did not, however, find support for an effect of Leucocytozoon infection on survival of adult female nesting Emperor Geese using a multi-state hidden Markov framework to analyze mark-resight and recapture data. Using parasite mitochondrial DNA cytochrome b sequences, we identified 23 haplotypes among infected Emperor Geese. Leucocytozoon haplotypes clustered into three phylogenetically supported clades designated as ‘L. simondi clade A’, ‘L. simondi clade B’, and ‘other Leucocytozoon’. We did not find evidence that parasites assigned to any of these clades were associated with differential mass measures among nesting adult female Emperor Geese. Collectively, our results provide negligible evidence for Leucocytozoon parasites as causing detrimental effects to adult female Emperor Geese breeding on the Yukon-Kuskokwim Delta.

Estimates of water use associated with continuous oil and gas development in the Permian Basin, Texas and New Mexico, 2010–19

Released August 26, 2021 10:24 EST

2021, Scientific Investigations Report 2021-5090

Joshua F. Valder, Ryan R. McShane, Joanna N. Thamke, Jeremy S. McDowell, Grady P. Ball, Natalie A. Houston, Amy E. Galanter

In 2015, the U.S. Geological Survey started a topical study to quantify water use in areas of continuous oil and gas (COG) development. The first phase of the study was completed in 2019 and analyzed the Williston Basin. The second phase of the study analyzed the Permian Basin using the same techniques and approaches used for the Williston Basin analysis. The Permian Basin was selected for the second phase of water-use analysis for the following reasons: (1) the basin has the largest undiscovered technically recoverable oil and gas resource in the United States, (2) the basin has a continuous resource in tight shale that primarily produces oil, and (3) the basin is within the contiguous United States. This study used data from 60 counties in Texas and New Mexico with spatial coverage based on the Permian Basin extent defined by the U.S. Energy Information Administration, a representation of the geologically defined Permian Basin.

Data from several sources were used in the analysis of direct, indirect, and ancillary water use associated with COG development in the Permian Basin and are available in an associated data release. Hydraulic fracturing water-use data were used to determine the start of the recent (before 2019) COG development boom in oil production in the Permian Basin in the same way that the data were used for the Williston Basin study. Water-use data were aggregated by county and year, which were the sampling units used in the analysis.

The water-use analysis of the Permian Basin contained three elements: (1) estimates of water use, in million gallons, by county and year; (2) coefficients of water use from regression models, in million gallons per developed oil and gas well; and (3) performance (based on goodness-of-fit metrics) of the regression models in estimating the observed water use.

Coefficients from the linear and quantile regression models of direct, indirect, and ancillary water use in the Permian Basin were produced as aggregate values for the counties and years. The mean estimate of direct water use had a 95-percent confidence interval of 4.13–5.45 million gallons (Mgal) per developed oil and gas well. The coefficient from the linear regression model of indirect water use was 0.111 Mgal per well, with a 95-percent confidence interval of 0.104–0.117 Mgal per well. The mean estimate of ancillary water use in the Permian Basin was 1.09 Mgal per well, with a 95-percent confidence interval of 1.05–1.13 Mgal per well. Model performance was evaluated with goodness-of-fit metrics including coefficient of determination (R2), root mean square error, and the ratio of root mean square error to standard deviation of observations computed from leave-one-out cross validation of the linear and quantile regression models of direct, indirect, and ancillary water use. Model performance for direct water use was acceptable, with an R2 value of 0.91. The model performance of indirect water use was acceptable, with an R2 value of 0.89. Values of R2 for the ancillary water-use categories were at least 0.89.

Annual mean estimates for hydraulic fracturing, cementing, drilling, indirect, and ancillary water use per well for the years 2010–17 were comparable between the Permian and Williston Basins. Hydraulic fracturing water use increased similarly from 2010 to 2015 in the Permian Basin and the Williston Basin, increasing from 0.6 Mgal per well in 2010 to 5.4 Mgal per well in 2015 in the Permian Basin and from 1.4 Mgal per well in 2010 to 4.7 Mgal per well in 2015 in the Williston Basin.

By design, the Permian water-use assessment is a simplification of a complex and continually developing system and therefore has uncertainty and limitations in the interpretation of results. Despite the modeling limitations, the results summarized in the report, when compared to other studies, compare well with water-use estimations. The favorable comparison highlights the transferability of the water-use methodology to other areas of COG development.

Movement dynamics of smallmouth bass (Micropterus dolomieu) in a large river-tributary system

Released August 26, 2021 09:55 EST

2019, Fisheries Management and Ecology (26) 590-599

Tyler Wagner, Megan K. Schall, Timothy Wertz, Geoffrey D. Smith, Vicki S. Blazer

Smallmouth bass, Micropterus dolomieu Lacepède, movement dynamics were investigated in a connected mainstem river-tributary system. Smallmouth bass moved large distances annually (n = 84 fish, average = 24.6 ± 25.9 km, range = 0.03 to 118 km) and had three peak movement periods (pre-spawn, post-spawn and overwintering). Movement into and out of tributaries was common, but the movement between mainstem river and tributary habitats varied among tagging locations and season. In general, a large proportion of fish that were tagged in tributaries moved out of the tributaries after spawning (22/30 fish). Because of the importance of fish movement patterns on population dynamics, the observed individual variability in movement, quantified using a hierarchical model, and the potential for long-distance movements are important considerations for smallmouth bass conservation and management. In addition, mainstem river-tributary connectivity appears to play an important role for smallmouth bass during key life history events.

Hydrologic conditions in Kansas, water year 2020

Released August 26, 2021 09:02 EST

2021, Fact Sheet 2021-3045

Chantelle Davis

The U.S. Geological Survey, in cooperation with Federal, State, and local agencies, maintains a long-term network of hydrologic monitoring stations in Kansas. This network included 219 real-time streamgages, 12 real-time reservoir-level monitoring stations, and 20 groundwater monitoring stations in water year (WY) 2020. A WY is a 12-month period from October 1 to September 30 and is designated by the calendar year in which it ends. Real-time data are verified by U.S. Geological Survey personnel throughout the year with regular measurements of streamflow, lake levels, and groundwater levels. Hydrologic data collected in real time aid in the understanding of, and decisions made involving, water resources of Kansas. Hydrologic conditions are assessed annually by comparing statistical analyses of current and past WY data for the period of record. The monitoring of hydrologic conditions in Kansas can provide critical information to meet several needs including water-resources management, protection of life and property, reservoir operations, agricultural practices, public supply, ecological assessments, and industrial and recreational purposes.

Rebounds, regresses, and recovery: A 15-year study of the coral reef community at Pila‘a, Kaua‘i after decades of natural and anthropogenic stress events

Released August 26, 2021 08:29 EST

2021, Marine Pollution Bulletin

Ku'ulei S. Rodgers, A. Richards Dona, Y. O. Stender, A. O. Tsang, J. H. J. Han, Rebecca Weible, Nancy G. Prouty, Curt D. Storlazzi, Andrew M. Graham

Pila‘a reef on the north shore of Kaua‘i, Hawai‘i was subjected to a major flood event in 2001 that deposited extensive sediment on the reef flat, resulting in high coral mortality. To document potential recovery, this study replicated benthic and sediment surveys conducted immediately following the event and 15 years later. Coral cores were analyzed to determine coral growth rates and density. Our results suggest that significant reduction in terrigenous sediments has led to partial ecosystem recovery based on coral species and colony increases, more balanced size frequency distributions, improved coral condition, and enhanced coral recruitment despite lack of recovery of large dead coral colonies. However, within this 15-year period, episodic storms and a bleaching event impeded the recovery process, preventing full recovery and continuously threatening the coral reef community. As climate change progresses, the intensity and frequency of these disturbances are predicted to increase.

System characterization report on the China-Brazil Earth Resources Satellite-4A (CBERS–4A)

Released August 26, 2021 08:13 EST

2021, Open-File Report 2021-1030-J

James C. Vrabel, Gregory L. Stensaas, Cody Anderson, Jon Christopherson, Minsu Kim, Seonkyung Park, Simon Cantrell

Executive Summary

This report addresses system characterization of the China-Brazil Earth Resources Satellite-4A (CBERS–4A) multispectral remote sensing satellite and is part of a series of system characterization reports produced and delivered by the U.S. Geological Survey Earth Resources Observation and Science Cal/Val Center of Excellence in 2021. These reports present and detail the methodology and procedures for characterization; present technical and operational information about the specific sensing system being evaluated; and provide a summary of test measurements, data retention practices, data analysis results, and conclusions.

CBERS–4A is a joint Chinese-Brazilian medium-resolution satellite launched in December 2019 by the China National Space Agency/National Institute for Space Research (Brazil) on a Chang Zheng 4B rocket from the Taiyuan Satellite Launch Center for Earth resources monitoring. The CBERS–4A mission continues the CBERS mission that has been in continual operation since the launch of CBERS–1 in 1999.

The CBERS–4A satellite was designed and built by Academia Chinesa de Tecnologia Espacial/National Institute for Space Research and uses the Phoenix-Eye bus. CBERS–4A carries the multispectral camera and wide field imager sensors for medium-resolution land imaging and the wide swath panchromatic and multispectral camera sensor for high-resolution land imaging. This assessment focused on the multispectral camera sensor only. More information on CBERS sensors is available in the “2020 Joint Agency Commercial Imagery Evaluation—Remote Sensing Satellite Compendium” and at

The Earth Resources Observation and Science Cal/Val Center of Excellence system characterization team completed data analyses to characterize the geometric (interior and exterior), radiometric, and spatial performances. Results of these analyses indicate that CBERS–4A provides an interior (band-to-band) geometric performance in the range of −0.02 to −0.16 pixel; an exterior geometric accuracy performance of −22.02 (−1.47 pixels) to −16.06 meters (−1.07 pixels); a radiometric accuracy performance of –0.006 to 0.925 (offset and slope); and a spatial performance for relative edge response in the range of 0.39 to 0.44, for full width at half maximum in the range of 2.38 to 2.56 pixels, and for a modulation transfer function at a Nyquist frequency in the range of 0.001 to 0.013.