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USGS2017

Safari Science: Assessing the reliability of citizen science data for wildlife surveys

Protected areas are the cornerstone of global conservation, yet financial support for basic monitoring infrastructure is lacking in 60% of them. Citizen science holds potential to address these shortcomings in wildlife monitoring, particularly for resource-limited conservation initiatives in developing countries – if we can account for the reliability of data produced by volunteer citizen scientists (VCS). This study tests the reliability of VCS data vs. data produced by trained ecologists, presenting a hierarchical framework for integrating diverse datasets to assess extra variability from VCS data. Our results show that while VCS data are likely to be overdispersed for our system, the overdispersion varies widely by species. We contend that citizen science methods, within the context of East African drylands, may be more appropriate for species with large body sizes, which are relatively rare, or those that form small herds. VCS perceptions of the charisma of a species may also influence their enthusiasm for recording it. Tailored programme design (such as incentives for VCS) may mitigate the biases in citizen science data and improve overall participation. However, the cost of designing and implementing high-quality citizen science programmes may be prohibitive for the small protected areas that would most benefit from these approaches. Synthesis and applications . As citizen science methods continue to gain momentum, it is critical that managers remain cautious in their implementation of these programmes while working to ensure methods match data purpose. Context-specific tests of citizen science data quality can improve programme implementation, and separate data models should be used when volunteer citizen scientists' variability differs from trained ecologists' data. Partnerships across protected areas and between protected areas and other conservation institutions could help to cover the costs of citizen science programme design and implementation.

Journal of Applied Ecology↗

USGS2001

Population size, survival, and movements of white-cheeked pintails in Eastern Puerto Rico

We estimated numbers and survival of White-cheeked Pintails (Anas bahamensis) in eastern Puerto Rico during 1996-1999. We also quantified their movements between Culebra Island and the Humacao Wildlife Refuge, Puerto Rico. Mark-resight population size estimates averaged 1020 pintails during nine, 3-month sampling periods from January 1997 to June 1999. On average, minimum regional counts were 38 % lower than mark-resight estimates (mean = 631). Adult survival was 0.51 ?? 0.09 (SE). This estimate is similar for other anatids of similar size but broader geographic distribution. The probability of pintails surviving and staying in Humacao was hiher (67 %) than for counterparts on Culebra (31 %). The probability of surviving and moving from Culebra to Humacao (41 %) was higher than from Humacao to Culebra (20 %). These findings, and available information on reproduction, indicate that the Humacao Wildlife Refuge refuge has an important role in the regional demography of pintails. Our findings on population numbers and regional survival are encouraging, given concerns about the species' status due to habitat loss and hunting. However, our outlook for the species is tempered by the remaining gaps in the population dynamics of pintails; for examples, survival estimates of broods and fledglings (age 0-1) are needed for a comprehensive status assessment. Until additional data are obtianed, White-cheeked Pintails should continue to be protectd from hunting in Puerto Rico.

Caribbean Journal of Science↗

USGS1999

The evolutionary history of steelhead ( Oncorhynchus mykiss ) along the US Pacific Coast: Developing a conservation strategy using genetic diversity

Changes in genetic variation across a species range may indicate patterns of population structure resulting from past ecological and demographic events that are otherwise difficult to infer and thus provide insight into evolutionary development. Genetic data is used, drawn from 11 microsatellite loci amplified from anadromous steelhead ( Oncorhynchus mykiss ) sampled throughout its range in the eastern Pacific Ocean, to explore population structure at the southern edge in California. Steelhead populations in this region represent less than 10% of their reported historic abundance and survive in very small populations found in fragmented habitats. Genetic data derived from three independent molecular systems (allozymes, mtDNA, and microsatellites) have shown that the southernmost populations are characterized by a relatively high genetic diversity. Two hypothetical models supporting genetic population substructure such as observed were considered: (1) range expansion with founder-flush effects and subsequent population decline; (2) a second Pleistocene radiation from the Gulf of California. Using genetic and climatic data, a second Pleistocene refugium contributing to a southern ecotone seems more feasible. These data support strong conservation measures based on genetic diversity be developed to ensure the survival of this uniquely diverse gene pool.

ICES Journal of Marine Science↗

USGS1981

A transient laboratory method for determining the hydraulic properties of 'tight' rocks-I. Theory

Transient pulse testing has been employed increasingly in the laboratory to measure the hydraulic properties of rock samples with low permeability. Several investigators have proposed a mathematical model in terms of an initial-boundary value problem to describe fluid flow in a transient pulse test. However, the solution of this problem has not been available. In analyzing data from the transient pulse test, previous investigators have either employed analytical solutions that are derived with the use of additional, restrictive assumptions, or have resorted to numerical methods. In Part I of this paper, a general, analytical solution for the transient pulse test is presented. This solution is graphically illustrated by plots of dimensionless variables for several cases of interest. The solution is shown to contain, as limiting cases, the more restrictive analytical solutions that the previous investigators have derived. A method of computing both the permeability and specific storage of the test sample from experimental data will be presented in Part II.

International Journal of Rock Mechanics and Mining↗

USGS2014

Mechanisms driving recruitment variability in fish: comparisons between the Laurentian Great Lakes and marine systems

In his seminal work, Hjort (in Fluctuations in the great fisheries of Northern Europe. Conseil Parmanent International Pour L'Exploration De La Mar. Rapports et Proces-Verbaux, 20: 1–228, 1914) observed that fish population levels fluctuated widely, year-class strength was set early in life, and egg production by adults could not alone explain variability in year-class strength. These observations laid the foundation for hypotheses on mechanisms driving recruitment variability in marine systems. More recently, researchers have sought to explain year-class strength of important fish in the Laurentian Great Lakes and some of the hypotheses developed for marine fisheries have been transferred to Great Lakes fish. We conducted a literature review to determine the applicability of marine recruitment hypotheses to Great Lakes fish. We found that temperature, interspecific interactions, and spawner effects (abundance, age, and condition of adults) were the most important factors in explaining recruitment variability in Great Lakes fish, whereas relatively fewer studies identified bottom-up trophodynamic factors or hydrodynamic factors as important. Next, we compared recruitment between Great Lakes and Baltic Sea fish populations and found no statistical difference in factors driving recruitment between the two systems, indicating that recruitment hypotheses may often be transferable between Great Lakes and marine systems. Many recruitment hypotheses developed for marine fish have yet to be applied to Great Lakes fish. We suggest that future research on recruitment in the Great Lakes should focus on forecasting the effects of climate change and invasive species. Further, because the Great Lakes are smaller and more enclosed than marine systems, and have abundant fishery-independent data, they are excellent candidates for future hypothesis testing on recruitment in fish.

Laurentian Great Lakes↗

USGS2014

Spatial variability in survival of adult brook trout within two intensively surveyed headwater stream networks

Headwater stream networks are considered heterogeneous riverscapes, but it is challenging to characterize spatial variability in demographic rates. We estimated site-scale (50 m) survival of adult (>age 1+) brook trout (Salvelinus fontinalis) within two intensively surveyed headwater stream networks by applying an open-population N-mixture approach to count data collected over two consecutive summers. The estimated annual apparent survival rate was 0.37 (95% CI: 0.28–0.46) in one network and 0.31 (95% CI: 0.15–0.45) in the other network. In both networks, trout survival was higher in stream sites characterized by more abundant pool habitats. Trout survival was negatively associated with mean depth in one network and positively associated with stream gradient in the other. Stream temperature was not related to trout survival in either network, possibly because the majority of sites were thermally suitable. A similar analytical approach can be useful for inferring survival rates when count data are available over space and time but individual tagging is not feasible.

Connecticut↗

USGS2003

Quantifying migratory delay: A new application of survival analysis

Statistical techniques commonly used in fish passage research fail to adequately quantify delays incurred at obstacles, or the effects of modifications to those obstacles on passage rates. Analyses of telemetry data describing these effects can be misleading, particularly when passage route of some individuals is not established (e.g., because of mortality, tag failure, passage through unmonitored or alternate routes, etc.). Here, we demonstrate how event-time analysis, better known as survival analysis, can be used to quantify passage rates for any study that allows tracking of individuals through time, even when some individuals fail to pass the route or obstacle in question. We review two of the primary methods of event-time analysis (parametric and Cox's proportional hazards regression analyses) and use them in combination with logistic regression to provide unbiased estimates of delay incurred at a hydroelectric facility, as well as insights on factors affecting both rates of passage and route selection. Passage rate increased with increased depth of a surface bypass sluice gate and, among fish that passed through the turbines, with turbine flow. The data further indicate that risk of turbine passage increased with both delay and turbine flow.

Canadian Journal of Fisheries and Aquatic Sciences↗

USGS2014

Model behavior and sensitivity in an application of the cohesive bed component of the community sediment transport modeling system for the York River estuary, VA, USA

The Community Sediment Transport Modeling System (CSTMS) cohesive bed sub-model that accounts for erosion, deposition, consolidation, and swelling was implemented in a three-dimensional domain to represent the York River estuary, Virginia. The objectives of this paper are to (1) describe the application of the three-dimensional hydrodynamic York Cohesive Bed Model, (2) compare calculations to observations, and (3) investigate sensitivities of the cohesive bed sub-model to user-defined parameters. Model results for summer 2007 showed good agreement with tidal-phase averaged estimates of sediment concentration, bed stress, and current velocity derived from Acoustic Doppler Velocimeter (ADV) field measurements. An important step in implementing the cohesive bed model was specification of both the initial and equilibrium critical shear stress profiles, in addition to choosing other parameters like the consolidation and swelling timescales. This model promises to be a useful tool for investigating the fundamental controls on bed erodibility and settling velocity in the York River, a classical muddy estuary, provided that appropriate data exists to inform the choice of model parameters.

Virginia↗

USGS2018

Acoustic telemetry observation systems: challenges encountered and overcome in the Laurentian Great Lakes

The Great Lakes Acoustic Telemetry Observation System (GLATOS), organized in 2012, aims to advance and improve conservation and management of Great Lakes fishes by providing information on behavior, habitat use, and population dynamics. GLATOS faced challenges during establishment, including a funding agency-imposed urgency to initiate projects, a lack of telemetry expertise, and managing a flood of data. GLATOS now connects 190+ investigators, provides project consultation, maintains a web-based data portal, contributes data to Ocean Tracking Network’s global database, loans equipment, and promotes science transfer to managers. The GLATOS database currently has 50+ projects, 39 species tagged, 8000+ fish released, and 150+ million tag detections. Lessons learned include (1) seek advice from others experienced in telemetry; (2) organize networks prior to when shared data is urgently needed; (3) establish a data management system so that all receivers can contribute to every project; (4) hold annual meetings to foster relationships; (5) involve fish managers to ensure relevancy; and (6) staff require full-time commitment to lead and coordinate projects and to analyze data and publish results.

Laurentian Great Lakes↗

USGS1990

Denitrification in sediments from the hyporheic zone adjacent to a small forested stream

Denitrifying potentials increased with increasing distance from the stream channel. Dissolved oxygen was 100% of the concentration expected in equilibrium with the atmosphere in water obtained from monitoring wells immediately adjacent to the stream but was as low as 7% of the expected value in water 11.4 m inland. Both nitrate and dissolved organic carbon decreased over summer in wells at the base of the alder-forested slope. A 48-h injection of nitrate-amended stream water into hyporheic water 8.4 m inland stimulated nitrous oxide production in the presence of acetylene. Nitrous oxide was generated as nitrate and acetylene were co-transported to a well 13 m down-gradient. Acetylene-block experiments coupled with the chemistry data suggest that denitrification can modify the chemistry of water during passage through the hyporheic zone. -from Authors

Canadian Journal of Fisheries and Aquatic Sciences↗

USGS1994

Evaluation of measurement scale using imbibition experiments in volcanic tuffs

A major issue in the site characterization at Yucca Mountain, Nevada, a potential site for a high-level nuclear waste repository, is the relevance of laboratory-scale measurements on cores to field-scale processes, particularly water flow. Calculation of Philip`s sorptivity parameter using imbibition of water into rock was selected as a simple test to describe hydrologic parameters at both laboratory and field scales and to study effects of sample size and spatial variability. Laboratory-scale imbibition experiments were conducted on two sizes of core from two boreholes drilled in layered nonwelded tuff and fractured welded tuff. Laboratory experiments were compared with field experiments in the boreholes using neutron logs and a field-scale Mariotte system. Measured sorptivity for both sizes of core were virtually identical and both could predict field-scale sorptivity if enough samples were used to account for spatial heterogeneity. Core data was less useful in predicting the neutron log data due to the nature of the neutron probe measurement and difficulties in accounting for effects of the unique system geometry. Mean neutron log values could not predict the field results from the welded borehole due to fractures transmitting but not retaining water, and could not predict laboratory results because of scale and sampling volume differences. The mean neutron log data could, however, approximate the large-scale field results in the nonwelded borehole.

Nevada↗

USGS2021

Contributed reports of widely felt earthquakes in California, United States: If they felt it, did they report it?

In a recent study, Hough and Martin (2021) considered the extent to which socioeconomic factors influence the numbers and distribution of contributed reports available to characterize the effects of both historical and recent large earthquakes. In this study I explore the question further, focusing on analysis of widely felt earthquakes near major population centers in northern and southern California since 2002. For most of these earthquakes there is a correlation between average household income in a postal ZIP code and the population-normalized rate of responses to the DYFI system. As past studies have demonstrated, there is also a strong correlation between DYFI participation and the severity of shaking. This first-order correlation can obscure correlations with other factors that influence participation. Focusing on five earthquakes between 2011 and 2021 that generated especially uniform shaking across the greater Los Angeles, California, region, response rate varies by two orders of magnitude across the region, with a clear correlation with demographics, and consistent spatial patterns in response rate for earthquakes 10 years apart. While there is no evidence that uneven DYFI participation in California impacts significantly the reliability of intensity data collected, the results reveal that DYFI participation is significantly higher in affluent parts of southern California compared to economically disadvantaged areas.

California↗

USGS2024

Groundwater-Surface water interactions research: Past trends and future directions

Interactions between groundwater and surface water sustain groundwater-dependent ecosystems and regulate river temperature and biogeochemical cycles, amongst many other processes. These interactions occur in freshwater environments including rivers, springs, lakes, and wetlands, and in coastal environments via tidal pumping, submarine groundwater discharge, and seawater intrusion. Here, we explore groundwater-surface water interactions research using bibliometric analyses of titles, abstracts, and keywords from 20,275 journal papers published between 1970 and 2023 extracted from Scopus. Analyses show that research into groundwater-surface water interactions is highly multi-disciplinary, with growing contributions from the social and biological sciences. The number of groundwater-surface water interactions papers is rapidly increasing with over 1200 papers published per year since 2020. Drawing on our data-driven approach and expert knowledge, we synthesise current research trends and identify critical future research directions. Despite the thousands of papers on groundwater-surface water interactions, important processes are still difficult to quantify or predict at meaningful spatial scales to inform water-resources management. We see benefits in future groundwater-surface water interactions research focusing on: (1) using new technologies including internet-of-things-based sensors, uncrewed vehicles, and remote-sensing approaches for data collection to inform groundwater-surface water interactions at large scales, (2) seeking approaches to upscale site-specific findings to better inform management, and (3) continuing the movement towards multi-disciplinary investigations to better inform the understanding of groundwater-surface water interactions and processes that will enable better management outcomes.

Journal of Hydrology↗

USGS2013

Correcting length-frequency distributions for imperfect detection

Sampling gear selects for specific sizes of fish, which may bias length-frequency distributions that are commonly used to assess population size structure, recruitment patterns, growth, and survival. To properly correct for sampling biases caused by gear and other sources, length-frequency distributions need to be corrected for imperfect detection. We describe a method for adjusting length-frequency distributions when capture and recapture probabilities are a function of fish length, temporal variation, and capture history. The method is applied to a study involving the removal of Smallmouth Bass Micropterus dolomieu by boat electrofishing from a 38.6-km reach on the Yampa River, Colorado. Smallmouth Bass longer than 100 mm were marked and released alive from 2005 to 2010 on one or more electrofishing passes and removed on all other passes from the population. Using the Huggins mark–recapture model, we detected a significant effect of fish total length, previous capture history (behavior), year, pass, year×behavior, and year×pass on capture and recapture probabilities. We demonstrate how to partition the Huggins estimate of abundance into length frequencies to correct for these effects. Uncorrected length frequencies of fish removed from Little Yampa Canyon were negatively biased in every year by as much as 88% relative to mark–recapture estimates for the smallest length-class in our analysis (100–110 mm). Bias declined but remained high even for adult length-classes (≥200 mm). The pattern of bias across length-classes was variable across years. The percentage of unadjusted counts that were below the lower 95% confidence interval from our adjusted length-frequency estimates were 95, 89, 84, 78, 81, and 92% from 2005 to 2010, respectively. Length-frequency distributions are widely used in fisheries science and management. Our simple method for correcting length-frequency estimates for imperfect detection could be widely applied when mark–recapture data are available.

Colorado↗

USGS2022

Combining fixed-location count data and movement data to estimate abundance of a lake sturgeon spawning run

Estimating abundance of migrating fishes is challenging. While sonars can be deployed continuously, improper assumptions about unidirectional migration and complete spatial coverage can lead to inaccurate estimates. To address these challenges, we present a framework for combining fixed-location count data from a dual-frequency identification sonar (DIDSON) with movement data from acoustic telemetry to estimate spawning run abundance of lake sturgeon ( Acipenser fulvescens ). Acoustic telemetry data were used to estimate the probability of observing a lake sturgeon on the DIDSON and to determine the probability that a lake sturgeon passing the DIDSON site had passed the site previously during the season. Combining probabilities with DIDSON counts, using a Bayesian integrated model, we estimated the following abundances: 99 (42–215 credible interval, CI) in 2017, 131 (82–248 CI) in 2018, and 92 (47–184 CI) in 2019. Adding movement data generated better inferences on count data by incorporating fish behavior (e.g., multiple migrations in a single season) and its uncertainty into abundance estimates. This framework can be applied to count and movement data to estimate abundance of spawning runs of other migratory fishes in riverine systems.

Vermont↗

USGS2002

Groundwater contamination downstream of a contaminant penetration site. II. Horizontal penetration of the contaminant plume

Part I of this study (Rubin, H.; Buddemeier, R.W. Groundwater Contamination Downstream of a Contaminant Penetration Site Part 1: Extension-Expansion of the Contaminant Plume. J. of Environmental Science and Health Part A (in press).) addressed cases, in which a comparatively thin contaminated region represented by boundary layers (BLs) developed within the freshwater aquifer close to contaminant penetration site. However, at some distance downstream from the penetration site, the top of the contaminant plume reaches the top or bottom of the aquifer. This is the location of the "attachment point," which comprises the entrance cross section of the domain evaluated by the present part of the study. It is shown that downstream from the entrance cross section, a set of two BLs develop in the aquifer, termed inner and outer BLs. It is assumed that the evaluated domain, in which the contaminant distribution gradually becomes uniform, can be divided into two sections, designated: (a) the restructuring section, and (b) the establishment section. In the restructuring section, the vertical concentration gradient leads to expansion of the inner BL at the expense of the outer BL, and there is almost no transfer of contaminant mass between the two layers. In the establishment section, each of the BLs occupies half of the aquifer thickness, and the vertical concentration gradient leads to transfer of contaminant mass from the inner to the outer BL. By use of BL approximations, changes of salinity distribution in the aquifer are calculated and evaluated. The establishment section ends at the uniformity point, downstream from which the contaminant concentration profile is practically uniform. The length of the restructuring section, as well as that of the establishment section, is approximately proportional to the aquifer thickness squared, and is inversely proportional to the transverse dispersivity. The study provides a convenient set of definitions and terminology that are helpful in visualizing the gradual development of uniform contaminant concentration distribution in an aquifer subject to contaminant plume penetration. The method developed in this study can be applied to a variety of problems associated with groundwater quality, such as initial evaluation of field data, design of field data collection, the identification of appropriate boundary conditions for numerical models, selection of appropriate numerical modeling approaches, interpretation and evaluation of field monitoring results, etc.

Journal of Environmental Science and Health - Part↗

USGS2002

Lag times of bank filtration at a well field, Cincinnati, Ohio, USA

Wells placed next to surface-water bodies to induce infiltration have come under scrutiny because of the presence of the potential pathogens in surface water. Removal of pathogens and other contaminants by bank filtration is assumed, but regulatory agencies question the effectiveness of this process. To investigate transport processes of biological constituents, advective groundwater traveltimes to production wells under the influence of surface water need to be established first to determine appropriate water-quality sampling schedules. This paper presents the results of a study of bank filtration at a well field in southwestern Ohio. Field parameters such as water level, specific conductance, and water temperature were measured at least hourly at a streamflow gaging station and at five monitoring wells each at two separate sites, corresponding to two nearby production wells. Water-quality samples also were collected in all wells and the streamflow gaging station. Specific conductance is directly related to concentration of chloride, a chemically conservative constituent. Cross-correlation methods were used to determine the average traveltime from the river to the monitoring wells. Traveltimes based on specific conductance ranged from approximately 20 h to 10 days at one site and 5 days to 3 months at the other site. Calculated groundwater flow velocities ranged from 2.1 ?? 10-3 to 6.0 ?? 10-3 cm/s and 3.5 ?? 10-4 to 7.1 ?? 10-4 cm/s at the two sites. Data collected when a production well is continuously pumping reveal shorter and more consistent traveltimes than when the same well is pumped intermittently. ?? 2002 Elsevier Science B.V. All rights reserved.

Journal of Hydrology↗

USGS2010

The IGBP-DIS global 1 km land cover data set, DISCover: First results

The International Geosphere-Biosphere Programme Data and Information System (IGBP-DIS) is co-ordinating the development of global land data sets from Advanced Very High Resolution Radiometer (AVHRR) data. The first is a 1 km spatial resolution land cover product 'DISCover', based on monthly Normalized Difference Vegetation Index composites from 1992 and 1993. DISCover is a 17 class land cover dataset based on the science requirements of IGBP elements. Mapping uses unsupervised classification with post-classification refinement using ancillary data. Draft Africa, North America and South America products are now available for peer review.

International Journal of Remote Sensing↗