SEARCH · Geology Reports

Results for “Nature Methods”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,225 records · Page 68Linked to original sources

USGS2012

Method for estimating potential wetland extent by utilizing streamflow statistics and flood-inundation mapping techniques: Pilot study for land along the Wabash River near Terre Haute, Indiana

Potential wetland extents were estimated for a 14-mile reach of the Wabash River near Terre Haute, Indiana. This pilot study was completed by the U.S. Geological Survey in cooperation with the U.S. Department of Agriculture, Natural Resources Conservation Service (NRCS). The study showed that potential wetland extents can be estimated by analyzing streamflow statistics with the available streamgage data, calculating the approximate water-surface elevation along the river, and generating maps by use of flood-inundation mapping techniques. Planning successful restorations for Wetland Reserve Program (WRP) easements requires a determination of areas that show evidence of being in a zone prone to sustained or frequent flooding. Zone determinations of this type are used by WRP planners to define the actively inundated area and make decisions on restoration-practice installation. According to WRP planning guidelines, a site needs to show evidence of being in an "inundation zone" that is prone to sustained or frequent flooding for a period of 7 consecutive days at least once every 2 years on average in order to meet the planning criteria for determining a wetland for a restoration in agricultural land. By calculating the annual highest 7-consecutive-day mean discharge with a 2-year recurrence interval (7MQ2) at a streamgage on the basis of available streamflow data, one can determine the water-surface elevation corresponding to the calculated flow that defines the estimated inundation zone along the river. By using the estimated water-surface elevation ("inundation elevation") along the river, an approximate extent of potential wetland for a restoration in agricultural land can be mapped. As part of the pilot study, a set of maps representing the estimated potential wetland extents was generated in a geographic information system (GIS) application by combining (1) a digital water-surface plane representing the surface of inundation elevation that sloped in the downstream direction of flow and (2) land-surface elevation data. These map products from the pilot study will aid the NRCS and its partners with the onsite inundation-zone verification in agricultural land for a potential restoration and will assist in determining at what elevation to plant hardwood trees for increased survivability on ground above frequently flooded terraces.

Indiana↗

USGS2020

Flood-frequency estimation for very low annual exceedance probabilities using historical, paleoflood, and regional information with consideration of nonstationarity

Streamflow estimates for floods with an annual exceedance probability of 0.001 or lower are needed to accurately portray risks to critical infrastructure, such as nuclear powerplants and large dams. However, extrapolating flood-frequency curves developed from at-site systematic streamflow records to very low annual exceedance probabilities (less than 0.001) results in large uncertainties in the streamflow estimates. Traditionally, methods for statistically estimating flood frequency have relied on the systematic streamflow record, which provides a time series of annual maximum flood peaks, often including some historical peaks. However, most peak-flow records are less than 100 years, and uncertainties are large when trying to extrapolate magnitudes of very low annual exceedance probability events. Other data may be available that extend the record beyond the systematic dataset. Historical data are defined as data from outside the period of systematic records but within the period of human records. Examples of historical information include flood estimates from other agencies and newspaper accounts that can be translated to flood magnitude point estimates, interval estimates, or perception thresholds (such as a statement that an 1880 flood was the largest since 1869). Paleoflood data, which may also extend the dataset, include a broad range of information about flood occurrence or magnitude from sources like sediment deposits or tree rings. Several assumptions are made in flood-frequency analysis, and an understanding of whether the data conform to these assumptions is desired. A particularly difficult assumption to evaluate for flood-frequency analysis is the underlying assumption that the flood series is stationary—the assumption that a time series of peak flow varies around a constant mean within a particular range of values (constant variance). As the hydrologic community’s understanding of natural systems and anthropogenic effects on streamflows has evolved, the community has come to understand that many surface-water systems exhibit one or more forms of nonstationarity, and thus the stationarity assumption is often violated to some degree. However, there is currently (2020) no consensus among hydrologists regarding the most appropriate flood-frequency-analysis methods for nonstationary systems, and this topic remains an active area of research. A literature review was completed to summarize the state of the science of flood frequency. The literature review highlights tools available to detect nonstationarities and identifies approaches that include external information to inform flood-frequency analysis. To demonstrate methods for initial data analysis and for incorporating historical and paleoflood information in flood-frequency analysis, five sites were selected: the Red River of the North at James Avenue Pumping Station, Winnipeg, Manitoba, Canada; lower reach, Rapid Creek, South Dakota; Spring Creek, South Dakota; Cherry Creek near Melvin, Colorado; and Escalante River near Escalante, Utah. The sites were chosen for the availability of published historical and paleoflood data and for their geographic diversity and unique characteristics, which highlighted issues such as autocorrelation, change points, trends, outlier peaks, or short periods of record. An initial data analysis that involved examining records for autocorrelation, change points, and trends was completed for all sites. The flood-frequency analysis completed for this study used version 7.2 of the U.S. Geological Survey PeakFQ program. Multiple analyses were done on each site documenting the change in the flood-frequency curve when additional historical or paleoflood data were added. When other flood-frequency studies were available, their results were compared to the results here. The comparisons in some cases simply show the effect of additional years of data, whereas other comparisons show results from probability distributions or fitting methods other than those used in PeakFQ. For the Red River of the North, flood-frequency analysis shows that paleoflood data appear necessary to reasonably estimate very low annual exceedance probabilities. For the analysis of the lower reach of Rapid Creek and Spring Creek, paleoflood information helped put a high outlier from the systematic period in context; however, very low annual exceedance probabilities at these sites still had extraordinarily large confidence bounds. These sites also showed that paleoflood information might be transferred from one site to another, with the caveat that this is a case where we had existing paleoflood data to test the transfer of paleoflood information—this is not the case at many sites, and transferring paleoflood information requires assumptions about the comparability of floods at the sites. The Cherry Creek analysis affirmed the result of an earlier study that showed that the generalized Pareto distribution was not a good distribution for estimating very low annual exceedance probabilities. The Escalante River analysis showed that adding paleoflood information might increase uncertainty for very low annual exceedance probabilities, compared to analysis with the systematic period of record information only, when the paleoflood peaks are of much larger magnitudes than the systematic record.

Scientific Investigations Report↗

USGS2026

Quality and quantity of terrestrial landscape connectivity in the US Great Lakes Coastal Zone

Context The Great Lakes Coastal Zone (GLCZ), the world’s longest continuous freshwater coastline, consists of interspersed natural and developed landcover and is inhabited by millions of people. Anthropogenic change fragments the GLCZ, decreasing landscape connectivity. Objectives We evaluated functional landscape connectivity of the U.S. GLCZ, assessing regional connectivity, protected areas’ effects on connectivity, and identified pinchpoints where connectivity is most vulnerable. Methods We modeled landscape connectivity to describe corridors and redundant pathways for two scenarios: (1) continuous terrestrial habitat patches and (2) protected areas. We compared these two scenarios by total corridor area and quality at two spatial scales (coastal zone and ecoregion). We used random forest analyses to examine how ecological factors influenced the connectivity rank and pinchpoint values. A principal components analysis identified how land cover influenced connectivity among ecoregions. Results The GLCZ was 69% connected. Although 91% of the GLCZ’s high-quality habitat was within corridors, less than 50% of the corridor area was high-quality (low resistance to movement). While the northernmost region retained high-quality connectivity, connectivity loss and degradation increased with development further south. Corridors between protected areas provided less connectivity, of worse quality, in areas of development and agriculture. Lower connectivity was associated with higher impervious surface cover. Conclusions Protected area placement affected both the quantity and quality of connectivity. Improving and maintaining functional connectivity could be accomplished by strategically restoring and protecting habitats most vulnerable to connectivity loss, predominantly in urban and agricultural regions. Our connectivity improvement index is a useful tool to identify areas where connectivity may be improved.

Illinois, Indiana, Michigan, Minnesota, New York, ↗

USGS2023

Elevation-based probabilistic mapping of irregularly flooded wetlands along the northern Gulf of Mexico coast

Irregularly flooded wetlands are found above the mean high water tidal datum and are exposed to tides and saltwater less frequently than daily. These wetlands provide important ecosystem services, such as providing habitat for fish and wildlife, enhancing water quality, ameliorating flooding impacts, supporting coastal food webs, and protecting upslope areas from erosion. Mapping irregularly flooded wetlands is challenging given their expansive coverage and dynamic nature. Furthermore, coastal wetlands are expected to change over the coming century due to sea-level rise and changes in the frequency and intensity of extreme storms. Consequently, coastal managers need baseline information on the spatial distribution of wetlands along with efficient and repeatable methods for observing changes. In this study, we used coastal wetlands from existing land use land cover data, best available lidar-derived digital elevation models, and Monte Carlo simulations to incorporate elevation uncertainty to create a probabilistic map of irregularly flooded wetlands along the northern Gulf of Mexico coast (USA). Our approach integrated findings from a review of coastal wetland elevation error in lidar datasets and an analysis of spatial autocorrelations of wetland elevation. We found a positive correlation ( r = 0.563, p < 0.0001) when comparing the probability estimated from a digital elevation model and in situ elevation observations. The differences in probability had a mean bias error of −0.04 (i.e., digital elevation model-based probability tends to be slightly lower), a mean absolute error of 0.20, and a root mean square error of 0.26. Beyond this overall validation, we explored error metrics for land cover classes and lidar collection details. To quantify areal coverage of the probabilistic output, we classified the probability values into equal bins using an interval of 0.33. The areal coverage of the lowest probability bin (“unlikely”; probability ≤0.33) was separated into the upper and lower portions of the irregularly flooded wetland zone. Of the coastal wetlands along the northern Gulf of Mexico coast about 38% were classified as unlikely and low with the greatest coverage in south Louisiana and the Everglades and around 33% were classified as unlikely and high with the greatest coverage in the Everglades and Texas. The relative coverage within the highest probability bin (“likely”; probability >0.66) covered around 13%, with the greatest coverage in south Florida, south Louisiana, and Texas. The framework developed in this study can be transferred to other coastal wetland areas and updated to observe changes with sea-level rise.

Gulf of Mexico coastline↗

USGS2025

Field and laboratory evaluations of visible light as a cue for guiding downstream-migrating juvenile Sea Lamprey

Objective We evaluated white light as a potential guidance cue for juvenile Sea Lamprey Petromyzon marinus in a natural setting as well as the effect of water velocity (0.25-, 0.50-, 0.75-, and 1.0-m/s test velocities) on light guidance behavior in a controlled laboratory flume, and characterized emigration timing and movement rates in a small stream (∼10 m wide and 0.7 m deep). Methods Behaviors and rates of downstream movement were monitored using PIT telemetry in both studies. Results In the field study, downstream movement by juveniles released during October 30–November 27 appeared to be cued by precipitation-induced flow events when water temperatures ranged between 4°C and 8°C. Juveniles expressed lateral attraction to a short, bank-mounted linear light array, but the guidance effect was not strong or consistent between bank light locations. Downstream movement rates decreased slightly when juveniles were exposed to the light cue. In the laboratory flume experiment, at water velocities of 0.25 and 0.75 m/s, lamprey were 2.8 and 3.3 times more likely to be detected at antennas along a wall with a linear light array compared with other antennas across the width of the flume. Significant changes in distribution were detected farther upstream in the flume during 0.25- and 0.50-m/s water velocity trials compared with 0.75-m/s trials. Further, the rate of downstream movement through the length of the flume decreased under artificial lighting compared with dark controls under the 0.25- and 0.75-m/s velocity conditions. Conclusions The results suggest lamprey exhibit a behavioral response to the light cue in both lab and field, but water velocity influences how effectively juveniles can respond to light cues.

Massachusetts↗

USGS2014

Assessing the risk persistent drought using climate model simulations and paleoclimate data

Projected changes in global rainfall patterns will likely alter water supplies and ecosystems in semiarid regions during the coming century. Instrumental and paleoclimate data indicate that natural hydroclimate fluctuations tend to be more energetic at low (multidecadal to multicentury) than at high (interannual) frequencies. State-of-the-art global climate models do not capture this characteristic of hydroclimate variability, suggesting that the models underestimate the risk of future persistent droughts. Methods are developed here for assessing the risk of such events in the coming century using climate model projections as well as observational (paleoclimate) information. Where instrumental and paleoclimate data are reliable, these methods may provide a more complete view of prolonged drought risk. In the U.S. Southwest, for instance, state-of-the-art climate model projections suggest the risk of a decade-scale megadrought in the coming century is less than 50%; the analysis herein suggests that the risk is at least 80%, and may be higher than 90% in certain areas. The likelihood of longer-lived events (>35 yr) is between 20% and 50%, and the risk of an unprecedented 50-yr megadrought is nonnegligible under the most severe warming scenario (5%–10%). These findings are important to consider as adaptation and mitigation strategies are developed to cope with regional impacts of climate change, where population growth is high and multidecadal megadrought—worse than anything seen during the last 2000 years—would pose unprecedented challenges to water resources in the region.

Journal of Climate↗

USGS1996

Sublake geologic structure from high-resolution seismic-reflection data from four sinkhole lakes in the Lake Wales Ridge, central Florida

Seismic-reflection profiles from Lake Wales, Blue Lake, Lake Letta, and Lake Apthorp located along the Lake Wales Ridge in central Florida provide local detail within the regional hydrogeologic framework as described by litho- and hydrostratigraphic cross sections. Lakes located with the mantled karst region have long been considered to be sinkhole lakes, originating from subsidence activity. High-resolution seismic- reflection data confirm this origin for these four lakes. The geologic framework of the Lake Wales Ridge has proven to be a suitable geologic setting for continuous high-resolution seismic-reflection profiling in lakes; however, the nature of the lake-bottom sediments largely controls the quality of the seismic data. In lakes with significant organic-rich bottom deposits, interpretable record was limited to areas where organic deposits were minimal. In lakes with clean, sandy bottoms, the seismic-reflection methods were highly successful in obtaining data that can be correlated with sublake subsidence features. These techniques are useful in examining sublake geology and providing a better understanding of how confining units are affected by subsidence in a region where their continuity is of significant importance to local lake hydrology. Although local geologic control around each lake generally corresponds to the regional geologic framework, local deviations from regional geologic trends occur in sublake areas affected by subsidence activity. Each of the four lakes examined represents a unique set of geologic controls and provides some degree of structural evidence of subsidence activity. Sublake geologic structures identified include: (1) marginal lake sediments dipping into bathymetric lows, (2) lateral discontinuity of confining units including sags and breaches, (3) the disruption and reworking of overlying unconsolidated siliciclastic sediments as they subside into the underlying irregular limestone surface, and (4) sublake regions where confining units appear to remain intact and unaffected by nearby subsidence activity. Each lake likely is underlain by several piping features rather than one large subsidence feature.

Florida↗

USGS2001

Documentation and verification of VST2D; a model for simulating transient, Variably Saturated, coupled water-heat-solute Transport in heterogeneous, anisotropic 2-Dimensional, ground-water systems with variable fluid density

This report describes a model for simulating transient, Variably Saturated, coupled water-heatsolute Transport in heterogeneous, anisotropic, 2-Dimensional, ground-water systems with variable fluid density (VST2D). VST2D was developed to help understand the effects of natural and anthropogenic factors on quantity and quality of variably saturated ground-water systems. The model solves simultaneously for one or more dependent variables (pressure, temperature, and concentration) at nodes in a horizontal or vertical mesh using a quasi-linearized general minimum residual method. This approach enhances computational speed beyond the speed of a sequential approach. Heterogeneous and anisotropic conditions are implemented locally using individual element property descriptions. This implementation allows local principal directions to differ among elements and from the global solution domain coordinates. Boundary conditions can include time-varying pressure head (or moisture content), heat, and/or concentration; fluxes distributed along domain boundaries and/or at internal node points; and/or convective moisture, heat, and solute fluxes along the domain boundaries; and/or unit hydraulic gradient along domain boundaries. Other model features include temperature and concentration dependent density (liquid and vapor) and viscosity, sorption and/or decay of a solute, and capability to determine moisture content beyond residual to zero. These features are described in the documentation together with development of the governing equations, application of the finite-element formulation (using the Galerkin approach), solution procedure, mass and energy balance considerations, input requirements, and output options. The VST2D model was verified, and results included solutions for problems of water transport under isohaline and isothermal conditions, heat transport under isobaric and isohaline conditions, solute transport under isobaric and isothermal conditions, and coupled water-heat-solute transport. The first three problems considered in model verification were compared to either analytical or numerical solutions, whereas the coupled problem was compared to measured laboratory results for which no known analytic solutions or numerical models are available. The test results indicate the model is accurate and applicable for a wide range of conditions, including when water (liquid and vapor), heat (sensible and latent), and solute are coupled in ground-water systems. The cumulative residual errors for the coupled problem tested was less than 10–8 cubic centimeter per cubic centimeter, 10-5 moles per kilogram, and 102 calories per cubic meter for liquid water content, solute concentration and heat content, respectively. This model should be useful to hydrologists, engineers, and researchers interested in studying coupled processes associated with variably saturated transport in ground-water systems.

Water-Resources Investigations Report↗

USGS2000

Methods for estimating low-flow statistics for Massachusetts streams

Methods and computer software are described in this report for determining flow duration, low-flow frequency statistics, and August median flows. These low-flow statistics can be estimated for unregulated streams in Massachusetts using different methods depending on whether the location of interest is at a streamgaging station, a low-flow partial-record station, or an ungaged site where no data are available. Low-flow statistics for streamgaging stations can be estimated using standard U.S. Geological Survey methods described in the report. The MOVE.1 mathematical method and a graphical correlation method can be used to estimate low-flow statistics for low-flow partial-record stations. The MOVE.1 method is recommended when the relation between measured flows at a partial-record station and daily mean flows at a nearby, hydrologically similar streamgaging station is linear, and the graphical method is recommended when the relation is curved. Equations are presented for computing the variance and equivalent years of record for estimates of low-flow statistics for low-flow partial-record stations when either a single or multiple index stations are used to determine the estimates. The drainage-area ratio method or regression equations can be used to estimate low-flow statistics for ungaged sites where no data are available. The drainage-area ratio method is generally as accurate as or more accurate than regression estimates when the drainage-area ratio for an ungaged site is between 0.3 and 1.5 times the drainage area of the index data-collection site. Regression equations were developed to estimate the natural, long-term 99-, 98-, 95-, 90-, 85-, 80-, 75-, 70-, 60-, and 50-percent duration flows; the 7-day, 2-year and the 7-day, 10-year low flows; and the August median flow for ungaged sites in Massachusetts. Streamflow statistics and basin characteristics for 87 to 133 streamgaging stations and low-flow partial-record stations were used to develop the equations. The streamgaging stations had from 2 to 81 years of record, with a mean record length of 37 years. The low-flow partial-record stations had from 8 to 36 streamflow measurements, with a median of 14 measurements. All basin characteristics were determined from digital map data. The basin characteristics that were statistically significant in most of the final regression equations were drainage area, the area of stratified-drift deposits per unit of stream length plus 0.1, mean basin slope, and an indicator variable that was 0 in the eastern region and 1 in the western region of Massachusetts. The equations were developed by use of weighted-least-squares regression analyses, with weights assigned proportional to the years of record and inversely proportional to the variances of the streamflow statistics for the stations. Standard errors of prediction ranged from 70.7 to 17.5 percent for the equations to predict the 7-day, 10-year low flow and 50-percent duration flow, respectively. The equations are not applicable for use in the Southeast Coastal region of the State, or where basin characteristics for the selected ungaged site are outside the ranges of those for the stations used in the regression analyses. A World Wide Web application was developed that provides streamflow statistics for data collection stations from a data base and for ungaged sites by measuring the necessary basin characteristics for the site and solving the regression equations. Output provided by the Web application for ungaged sites includes a map of the drainage-basin boundary determined for the site, the measured basin characteristics, the estimated streamflow statistics, and 90-percent prediction intervals for the estimates. An equation is provided for combining regression and correlation estimates to obtain improved estimates of the streamflow statistics for low-flow partial-record stations. An equation is also provided for combining regression and drainage-area ratio estimates to obtain improved e

Massachusetts↗

USGS1996

Geohydrology of the Stockton Formation and cross-contamination through open boreholes, Hatboro Borough and Warminster Township, Pennsylvania

The study area consists of a 9-square-mile area underlain by sedimentary rocks of the middle arkose member of the Stockton Formation of Upper Triassic age. In the Hatboro area, the Stockton Formation strikes approximately N. 65 degrees E. and dps approximately 9 degrees NW. The rocks are chiefly arkosic sandstone and siltstone. Rocks of the Stocton Formation form a complex, heterogeneous, multiaquifer system consisting of a series of gently dipping lithologic units with different hydraulic properties. Most ground water in the unweathered zone moves through a network of interconnecting secondary openigns-fractures, bedding plans, and joints. Ground water is unconfined in the shallower part of the aquifer and semiconfined or confined in the deeper part of the aquifer. Nearly all deep wells in the Stockton Formation are open to several water-bearing zones and are multiaquifer wells. Each water-bearing zone usually has a different hydraulic head. Where differences in hydraulic head exist between water-bearing zones, water in the well bore flows under nonpumping conditions in the direction of decreasing head. Determination of the potential for borehole flow was based on caliper, natural-gamma, single- point-resistance, fluid-resistivity, and (or) fluid-temperature logs that were run in 162 boreholes 31 to 655 feet deep. The direction and rate of borehole-fluid movement were determined in 83 boreholes by the bring-tracing method and in 10 boreholes by use of a heat-pulse flowmeter. Borehole flow was measurable in 65 of the 93 boreholes (70 percent). Fluid movement at rates up to 17 gallons per minute was measured. Downward flow was measured in 36 boreholes, and upward flow was measured in 23 boreholes, not including those boreholes in which two directions of flow were measured. Both upward and downward vertical flow was measured in six boreholes; these boreholes are 396 to 470 feet deep and were among the deepest boreholes logged. Fluid movement was upward in the upper part of the borehole and downward in the lower part of the borehole in two boreholes. Fluid movement wad downward in the upper part of the borehole and upward in the lower part of the borehole in three boreholes. Groung-water contamination by volatile organic compounds (VOC's) is widespread in the study area. Detectable concentrations of VOC's were present in water samples from 24 wells sampled in Hatboro Brough and in water samples for 10 of 14 wells (71 percent) samples in Warminster Township. Samples of borehole flow from nine boreholes in the industrial area of Hatboro were collected for laboratory analysis to estimate the quantity of VOC's in borehole flow. Downward flow was measured in all of these boreholes. Concentrations of TCE, TCA, and 1,1-DCE as great at 5,800, 1,400 and 260 micrograms per liter, respectively, show that some water moving downward in the aquifer through these open boreholes is highly contaminated and that open boreholes may contribute substantially to ground-water contamination. An estimated 14.7 gallons per year of VOC's were moving downward through the nine open boreholes sampled from the contaminated, upper part of the aquifer to the lower part, which is tapped by public supply wells. Borehole geophysical logs were used as a guide to design and construct monitor-well networks at three National Priorities List sites in the area. An open borehole was dirlled, and a suite of geophysical logs was run. Interpretation of geophysical logs enabled the identification of water-bearing zones that produce and receive water; these are zones that should not be connected. From the logs, discrete intervals to be monitored were selected. In the Stockton Formation, the same water-bearing zone may not be intersected in adjacent boreholes, especially if it is a vertical fracture with a diffident magnetic orientation than that of the adjacent boreholes. In most areas of the stockton Formation, depth of water-bearing zones in an are

Pennsylvania↗

USGS2006

Sex determination of Pohnpei Micronesian kingfishers using morphological and molecular genetic techniques

Conservation-oriented studies of Micronesian Kingfishers (Todiramphus cinnamominus) have been hindered by a lack of basic natural history information, despite the status of the Guam subspecies (T. c. cinnamominus) as one of the most endangered species in the world. We used tissue samples and morphometric measures from museum specimens and wild-captured Pohnpei Micronesian Kingfishers (T. c. reichenbachii) to develop methods for sex determination. We present a modified molecular protocol and a discriminant function that yields the probability that a particular individual is male or female. Our results revealed that females were significantly larger than males, and the discriminant function correctly predicted sex in 73% (30/41) of the individuals. The sex of 86% (18/21) of individuals was correctly assigned when a moderate reliability threshold was set. Sex determination using molecular genetic techniques was more reliable than methods based on morphology. Our results will facilitate recovery efforts for the critically endangered Guam Micronesian Kingfisher and provide a basis for sex determination in the 11 other endangered congeners in the Pacific Basin.

Journal of Field Ornithology↗

USGS2009

Applications of a broad-spectrum tool for conservation and fisheries analysis: Aquatic gap analysis

Natural resources support all of our social and economic activities, as well as our biological existence. Humans have little control over most of the physical, biological, and sociological conditions dictating the status and capacity of natural resources in any particular area. However, the most rapid and threatening influences on natural resources typically are anthropogenic overuse and degradation. In addition, living natural resources (i.e., organisms) do not respect political boundaries, but are aware of their optimal habitat and environmental conditions. Most organisms have wider spatial ranges than the jurisdictional boundaries of environmental agencies that deal with them; even within those jurisdictions, information is patchy and disconnected. Planning and projecting effects of ecological management are difficult, because many organisms, habitat conditions, and interactions are involved. Conservation and responsible resource use involves wise management and manipulation of the aspects of the environment and biological communities that can be effectively changed. Tools and data sets that provide new insights and analysis capabilities can enhance the ability of resource managers to make wise decisions and plan effective, long-term management strategies. Aquatic gap analysis has been developed to provide those benefits. Gap analysis is more than just the assessment of the match or mis-match (i.e., gaps) between habitats of ecological value and areas with an appropriate level of environmental protection (e.g., refuges, parks, preserves), as the name suggests. Rather, a Gap Analysis project is a process which leads to an organized database of georeferenced information and previously available tools to examine conservation and other ecological issues; it provides a geographic analysis platform that serves as a foundation for aquatic ecological studies. This analytical tool box allows one to conduct assessments of all habitat elements within an area of interest. Aquatic gap analysis naturally focuses on aquatic habitats. The analytical tools are largely based on specification of the species-habitat relations for the system and organism group of interest (Morrison et al. 2003; McKenna et al. 2006; Steen et al. 2006; Sowa et al. 2007). The Great Lakes Regional Aquatic Gap Analysis (GLGap) project focuses primarily on lotic habitat of the U.S. Great Lakes drainage basin and associated states and has been developed to address fish and fisheries issues. These tools are unique because they allow us to address problems at a range of scales from the region to the stream segment and include the ability to predict species specific occurrence or abundance for most of the fish species in the study area. The results and types of questions that can be addressed provide better global understanding of the ecological context within which specific natural resources fit (e.g., neighboring environments and resources, and large and small scale processes). The geographic analysis platform consists of broad and flexible geospatial tools (and associated data) with many potential applications. The objectives of this article are to provide a brief overview of GLGap methods and analysis tools, and demonstrate conservation and planning applications of those data and tools. Although there are many potential applications, we will highlight just three: (1) support for the Eastern Brook Trout Joint Venture (EBTJV), (2) Aquatic Life classification in Wisconsin, and (3) an educational tool that makes use of Google Earth (use of trade or product names does not imply endorsement by the U.S. Government) and Internet accessibility.

Gap Analysis Bulletin↗

USGS2004

Herpetofaunal inventories of the National Parks of South Florida and the Caribbean: Volume I. Everglades National Park

Amphibian declines and extinctions have been documented around the world, often in protected natural areas. Concern for this alarming trend has prompted the U.S. Geological Survey and the National Park Service to document all species of amphibians that occur within U.S. National Parks and to search for any signs that amphibians may be declining. This study, an inventory of amphibian species in Everglades National Park, was conducted during 2000 to 2003. The goals of the project were to create a georeferenced inventory of amphibian species, use new analytical techniques to estimate proportion of sites occupied by each species, look for any signs of amphibian decline (missing species, disease, die-offs, etc.), and to establish a protocol that could be used for future monitoring efforts. Several sampling methods were used to accomplish all of these goals. Visual encounter surveys and anuran vocalization surveys were conducted in all habitats throughout the park to estimate the proportion of sites or proportion of area occupied (PAO) by each amphibian species in each habitat. Opportunistic collections, as well as some drift fence and aquatic funnel trap data were used to augment the visual encounter methods for highly aquatic or cryptic species. A total of 562 visits to 118 sites were conducted for standard sampling alone, and 1788 individual amphibians and 413 reptiles were encountered. Data analysis was done in program PRESENCE to provide PAO estimates for each of the anuran species. All but one of the amphibian species thought to occur in Everglades National Park was detected during this project. That species, the Everglades dwarf siren (Pseudobranchus axanthus belli), is especially cryptic and probably geographically limited in its range in Everglades National Park. The other three species of salamanders and all of the anurans in the park were sampled adequately using standard herpetological sampling methods. PAO estimates were produced for each species of anuran by habitat. This information is valuable now as an indicator of habitat associations of the species and relative abundance of sites occupied, but it will also be useful as a comparative baseline for future monitoring efforts. In addition to sampling for amphibians, all encounters with reptiles were documented. The sampling methods used for detecting amphibians are also appropriate for many reptile species. These reptile locations are included in this report, but there were not enough locations for most reptile species to analyze the PAO of individual species. 37 of the 57 species of reptiles thought to occur in Everglades National Park were detected during this study. This study found no evidence of amphibian decline in Everglades National Park. There was one species not detected, but there is no evidence to indicate it has been extirpated from the park. Although no declines were observed, several threats to amphibians were identified. Introduced species, especially the Cuban treefrog (Osteopilus septentrionalis), are predators and competitors with several native frog species. Also, interference by humans with the natural hydrological cycle of the Everglades has the potential to alter the amphibian community. Finally, habitat loss outside the park has the potential to leave the amphibians in Everglades National Park isolated from other populations. Continued monitoring of the amphibian species in Everglades National Park is recommended. The methods used in this study are adequate to produce reliable estimates of the proportion of sites occupied by most anuran species. Continuing this protocol is a cost-effective way of determining whether species are decreasing or increasing in abundance of sites occupied.

Open-File Report↗

USGS1976

Method and importance of obtaining humic and fulvic acids of high purity

A detailed procedure incorporating centrifugation, pressure filtration, dialysis, resin exchange, and freeze drying is given for the extraction and purification of fulvic and humic acids from soils and sediments. By use of the procedure humic acids have been prepared which have less than 0.22 percent ash. The isolation of relatively ash-free natural organic matter preparations is an essential prerequisite to the characterization of organic reactivity in natural systems. Inorganic impurities of amorphous and crystalline clay minerals and various inorganic metal ions often lead to numerous complications and errors during experimentation with organic matter because the inorganic substances associated with the organic phase cause variable reactivity of the organic substances.

Journal of Research of the U.S. Geological Survey↗

USGS2023

Matching existing and future native plant materials to disturbance-driven restoration needs

Assessing the appropriateness of existing native plant materials can both determine which seed source to utilize for restoration projects, and identify locations for which new seed sources need to be developed. Here, we demonstrate an approach to meet these needs. This method identifies areas of high restoration need based on disturbance patterns, assesses the regional suitability of existing native plant materials based on climate similarity, and highlights geographic (and climatic) gaps where existing materials are likely unsuitable and where plant material development projects can be prioritized. We examined 12 high priority restoration species across the Colorado Plateau, a 38-million-ha region of the Intermountain West, United States to test our methodological pipeline. Fifty-four percent of the Colorado Plateau is disturbed by livestock grazing, wildfires that have burned in the past 20 years, or energy production from oil and gas wells, natural gas pipelines, and coal mines. Of the 28 commercially available plant materials for six of the focal species, only 3 have climate similarity that encompass more than 50% of the species modeled habitat on the Colorado Plateau. Across all commercial materials, most species (10 of 12) do not have any suitable plant material for 70% or more of their geographic range on the Colorado Plateau. Of those areas identified as not having any suitable plant materials, 47–56% are also disturbed. Our method provides usable, flexible protocols and spatially referenced data sources for optimizing the planning of new native plant materials in any region where restoration is needed and spatial data are available.

Arizona, Colorado, New Mexico, Utah↗

USGS2004

Paleolimnology and paleoclimate studies in Upper Klamath Lake, Oregon

The subsiding Upper Klamath Lake Basin contains sediments that were continuously deposited in a shallow, freshwater lake for more than 40 000 years. Well dated by radiometric methods and containing volcanic ashes of known age, these sediments constitute a valuable paleoclimate record. Sediment constituents and properties that reflect past climatic conditions in the area include pollen, diatoms, sediment geochemistry, and sediment magnetic properties. Many of these proxy measurements are also useful for comparing natural conditions in the lake to conditions following human settlement. Because of its location, the paleoclimate record from Upper Klamath Lake is valuable for comparisons to offshore marine records and as part of latitudinal transects of paleoclimate records along the west coast of the Americas.

Oregon↗

USGS2017

Western bats as a reservoir of novel Streptomyces species with antifungal activity

At least two-thirds of commercial antibiotics today are derived from Actinobacteria , more specifically from the genus Streptomyces . Antibiotic resistance and new emerging diseases pose great challenges in the field of microbiology. Cave systems, in which actinobacteria are ubiquitous and abundant, represent new opportunities for the discovery of novel bacterial species and the study of their interactions with emergent pathogens. White-nose syndrome is an invasive bat disease caused by the fungus Pseudogymnoascus destructans , which has killed more than six million bats in the last 7 years. In this study, we isolated naturally occurring actinobacteria from white-nose syndrome (WNS)-free bats from five cave systems and surface locations in the vicinity in New Mexico and Arizona, USA. We sequenced the 16S rRNA region and tested 632 isolates from 12 different bat species using a bilayer plate method to evaluate antifungal activity. Thirty-six actinobacteria inhibited or stopped the growth of P. destructans , with 32 (88.9%) actinobacteria belonging to the genus Streptomyces . Isolates in the genera Rhodococcus , Streptosporangium , Luteipulveratus , and Nocardiopsis also showed inhibition. Twenty-five of the isolates with antifungal activity against P. destructans represent 15 novel Streptomyces spp. based on multilocus sequence analysis. Our results suggest that bats in western North America caves possess novel bacterial microbiota with the potential to inhibit P. destructans .

Applied and Environmental Microbiology↗

USGS2025

U.S. Geological Survey research and assessments supporting carbon dioxide removal

Both carbon capture and storage (CCS) and carbon dioxide removal (CDR) are methods to limit future global temperature rise and ocean acidification. CCS sequesters (stores) carbon dioxide (CO2) captured from industrial sources thereby preventing the CO2 from reaching the atmosphere. The captured CO2 is injected into underground geologic reservoirs or is converted into stable industrial products. CDR enhances natural processes or uses technical approaches to remove excess CO2 from the atmosphere. Carbon dioxide is sequestered in natural sinks such as vegetation and soil, or injected into underground reservoirs or converted into durable products. The U.S. Geological Survey (USGS) conducts research and resource assessments that support biologic and geologic CDR approaches. This report will review some of the ongoing USGS CDR research and assessment efforts.

Conference Paper↗