SEARCH · Geology Reports

Results for “Journal of Biological Systems”

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 127 records · Page 7Linked to original sources

USGS2023

Isothermal recombinant polymerase amplification and CRIPSR (CAS12A) assay detection of Renibacterium salmoninarum as an example for wildlife pathogen detection in environmental DNA samples

Improving rapid detection methods for pathogens is important for research as we collectively aim to improve the health of ecosystems globally. In the northern hemisphere, the success of salmon ( Oncorhynchus spp.) populations is vitally important to the larger marine, aquatic, and terrestrial ecosystems they inhabit. This has led to managers cultivating salmon in hatcheries and aquaculture to bolster their populations, but young salmon face many challenges, including diseases such as bacterial kidney disease (BKD). Early detection of the BKD causative agent, Renibacterium salmoninarum , is useful for managers to avoid outbreaks in hatcheries and aquaculture stocks to enable rapid treatment with targeted antibiotics. Isothermal amplification and CRIPSR-Cas12a systems may enable sensitive, relatively rapid, detection of target DNA molecules from environmental samples compared to quantitative PCR (qPCR) and culture methods. We used these technologies to develop a sensitive and specific rapid assay to detect R. salmoninarum from water samples using isothermal recombinase polymerase amplification (RPA) and an AsCas12a RNA-guided nuclease detection. The assay was specific to R. salmoninarum (0/10 co-occurring or closely related bacteria detected) and sensitive to 0.0128 pg/µL of DNA (approximately 20–40 copies/µL) within 10 min of Cas activity. This assay successfully detected R. salmoninarum environmental DNA in 14/20 water samples from hatcheries with known quantification for the pathogen via previous qPCR (70% of qPCR-positive samples). The RPA-CRISPR/AsCas12a assay had a limit of detection (LOD) of >10 copies/µL in the hatchery water samples and stochastic detection below 10 copies/µL, similar to but slightly higher than the qPCR assay. This LOD enables 37 C isothermal detection, potentially in the field, of biologically relevant levels of R. salmoninarum in water. Further research is needed to develop easy-to-use, cost-effective, sensitive RPA/CRISPR-AsCas12a assays for rapidly detecting low concentrations of wildlife pathogens in environmental samples.

Journal of Wildlife Diseases↗

USGS1998

Evaluation of two oral baiting systems for wild rodents

Tetracycline hydrochloride (TC)-treated peanut butter or rodent chow baits were distributed during March 1990, on separate 0.53 ha sites in Oglethorpe County, Georgia (USA). Rodents were trapped on a control site prior to bait distribution and on two baited sites 6 days post-distribution. Cleaned skulls from euthanized mammals were grossly examined for TC florescence using an ultraviolet (UV) light. Mandibles were sectioned and examined for TC fluorescence using an ultraviolet light microscope. All 21 cotton rats ( Sigmodon hispidus ), four eastern harvest mice ( Rithrodontomys humulis ), and two golden mice ( Ochrotomys nuttalli ) captured on the control site were negative for TC fluorescence. On the peanut butter bait site, mandible sections from 29 of 32 (91%) cotton rats, three of three (100%) eastern harvest mice, two of three (66%) golden mice, zero of five (0%) white-footed mice ( Peromyscus leucopus ), one of three (33%) short-tailed shrews ( Blarina brevicauda ), and zero of two (0%) least shrews ( Cryptotis parva ) were positive for TC. Results from the rodent chow bait site indicated that 18 of 25 (72%) cotton rats, zero of three (0%) eastern harvest mice, two of seven (29%) golden mice, zero of four (0%) white-footed mice, and zero of four (0%) least shrews were positive for TC fluorescence in mandible sections. These results suggest that a large portion of a free-ranging small rodent population can be administered biological markers or vaccines using baits.

Georgia↗

USGS1981

Geological considerations in hazardous waste disposal

Present regulations assume that long-term isolation of hazardous wastes - including toxic chemical, biological, radioactive, flammable and explosive wastes - may be effected by disposal in landfills that have liners of very low hydraulic conductivity. In reality, total isolation of wastes in humid areas is not possible; some migration of leachate from wastes buried in the gound will always occur. Regulations should provide performance standards applicable on a site-by-site basis rather than rigid criteria for site selection and design. The performance standards should take into account several factors: (1) the categories, segregation, degradation and toxicity of the wastes; (2) the site hydrogeology, which governs the direction and rate of contaminant transport; (3) the attenuation of contaminants by geochemical interactions with geologic materials; and (4) the release rate of unattenuated pollutants to surface or groundwater. An adequate monitoring system is essential. The system should both test the extent to which the operation of the site meets performance standards and provide sufficient warning of pollution problems to allow implementation of remedial measures. In recent years there has been a trend away from numerous, small disposal sites toward fewer and larger sites. The size of a disposal site should be based on the attenuation capacity of the geologic material, which has a finite, though generally not well-defined, limit. For slowly degradable wastes, engineered sites with leachate-collection systems appear to be only a temporary solution since the leachate collected will also require final disposal.

Journal of Hydrology↗

USGS2023

Landscape configuration alters movement behavior and space-use of a Hawaiian forest bird community

Habitat loss and fragmentation are considered the greatest threats to ecosystems worldwide. Movement reveals how individuals meet their habitat requirements and respond to environmental heterogeneity, and thus can provide a powerful tool for investigating how animals respond to changes in landscape configuration. In our study, we examined the effects of landscape configuration on the space use and movement strategies of four endemic Hawaiian forest bird species spanning a range of foraging guilds (i.e. frugivore, nectivore, generalist). We used a landscape-level automated radio tracking system to measure location data of 127 individuals tracked on Hawaiʻi Island in a naturally fragmented landscape created by volcanic activity in the mid- to late-1800s and a nearby continuous landscape. We found that landscape configuration had a strong effect on movement patterns and space-use of all four species. In the fragmented landscape, all species predominately occupied a single forest patch, displayed a high degree of area-restricted search behavior, with few long-distance movements away from their primary forest patch. These patterns contrasted significantly with those of conspecifics in the continuous landscape which exhibited relatively unconstrained movements across the forested landscape and had 3- to 12-fold larger home ranges. Our findings indicate that landscape structure plays a strong role in shaping movement behavior of a tropical bird community and provides valuable insights into the behavioral mechanisms that may be important for species to persist within fragmented landscapes.

Journal of Avian Biology↗

USGS2015

Quantitative attribution of major driving forces on soil organic carbon dynamics

Soil organic carbon (SOC) storage plays a major role in the global carbon cycle and is affected by many factors including land use/management changes (e.g., biofuel production-oriented changes). However, the contributions of various factors to SOC changes are not well understood and quantified. This study was designed to investigate the impacts of changing farming practices, initial SOC levels, and biological enhancement of grain production on SOC dynamics and to attribute the relative contributions of major driving forces (CO 2 enrichment and farming practices) using a fractional factorial modeling design. The case study at a crop site in Iowa in the United States demonstrated that the traditional corn-soybean (CS) rotation could still accumulate SOC over this century (from 4.2 to 6.8 kg C/m 2 ) under the current condition; whereas the continuous-corn (CC) system might have a higher SOC sequestration potential than CS. In either case, however, residue removal could reduce the sink potential substantially. Long-term simulation results also suggested that the equilibrium SOC level may vary greatly (∼5.7 to ∼11 kg C/m 2 ) depending on cropping systems and management practices, and projected growth enhancement could make the magnitudes higher (∼7.8 to ∼13 kg C/m 2 ). Importantly, the factorial design analysis indicated that residue management had the most significant impact (contributing 49.4%) on SOC changes, followed by CO 2 Enrichment (37%), Tillage (6.2%), the combination of CO 2 Enrichment-Residue removal (5.8%), and Fertilization (1.6%). In brief, this study is valuable for understanding the major forces driving SOC dynamics of agroecosystems and informative for decision-makers when seeking the enhancement of SOC sequestration potential and sustainability of biofuel production, especially in the Corn Belt region of the United States.

Journal of Advances in Modeling Earth Systems↗

USGS1993

Coupled effects of vertical mixing and benthic grazing on phytoplankton populations in shallow, turbid estuaries

Coastal ocean waters tend to have very different patterns of phytoplankton biomass variability from the open ocean, and the connections between physical variability and phytoplankton bloom dynamics are less well established for these shallow systems. Predictions of biological responses to physical variability in these environments is inherently difficult because the recurrent seasonal patterns of mixing are complicated by aperiodic fluctuations in river discharge and the high-frequency components of tidal variability. We might expect, then, less predictable and more complex bloom dynamics in these shallow coastal systems compared with the open ocean. Given this complex and dynamic physical environment, can we develop a quantitative framework to define the physical regimes necessary for bloom inception, and can we identify the important mechanisms of physical-biological coupling that lead to the initiation and termination of blooms in estuaries and shallow coastal waters? Numerical modeling provides one approach to address these questions. Here we present results of simulation experiments with a refined version of Cloern's (1991) model in which mixing processes are treated more realistically to reflect the dynamic nature of turbulence generation in estuaries. We investigated several simple models for the turbulent mixing coefficient. We found that the addition of diurnal tidal variation to Cloern's model greatly reduces biomass growth indicating that variations of mixing on the time scale of hours are crucial. Furthermore, we found that for conditions representative of South San Francisco Bay, numerical simulations only allowed for bloom development when the water column was stratified and when minimal mixing was prescribed in the upper layer. Stratification, however, itself is not sufficient to ensure that a bloom will develop: minimal wind stirring is a further prerequisite to bloom development in shallow turbid estuaries with abundant populations of benthic suspension feeders.

Journal of Marine Research↗

USGS2015

An empirical evaluation of landscape energetic models: Mallard and American black duck space use during the non-breeding period

Bird conservation Joint Ventures are collaborative partnerships between public agencies and private organizations that facilitate habitat management to support waterfowl and other bird populations. A subset of Joint Ventures has developed energetic carrying capacity models (ECCs) to translate regional waterfowl population goals into habitat objectives during the non-breeding period. Energetic carrying capacity models consider food biomass, metabolism, and available habitat to estimate waterfowl carrying capacity within an area. To evaluate Joint Venture ECCs in the context of waterfowl space use, we monitored 33 female mallards ( Anas platyrhynchos ) and 55 female American black ducks ( A. rubripes ) using global positioning system satellite telemetry in the central and eastern United States. To quantify space use, we measured first-passage time (FPT: time required for an individual to transit across a circle of a given radius) at biologically relevant spatial scales for mallards (3.46 km) and American black ducks (2.30 km) during the non-breeding period, which included autumn migration, winter, and spring migration. We developed a series of models to predict FPT using Joint Venture ECCs and compared them to a biological null model that quantified habitat composition and a statistical null model, which included intercept and random terms. Energetic carrying capacity models predicted mallard space use more efficiently during autumn and spring migrations, but the statistical null was the top model for winter. For American black ducks, ECCs did not improve predictions of space use; the biological null was top ranked for winter and the statistical null was top ranked for spring migration. Thus, ECCs provided limited insight into predicting waterfowl space use during the non-breeding season. Refined estimates of spatial and temporal variation in food abundance, habitat conditions, and anthropogenic disturbance will likely improve ECCs and benefit conservation planners in linking non-breeding waterfowl habitat objectives with distribution and population parameters. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Arkansas, Delaware, Louisiana, Michigan, New Jerse↗

USGS2023

America's most wanted fishes: Cataloging risk assessments to prioritize invasive species for management action

Hundreds of fish species enter the United States through human intervention (e.g., importation) and some of these fishes pose a substantial risk to the nation’s assets and ecosystems. Prevention, early detection, and rapid response (EDRR) are vital to stop species invasions, but time and resources to manage the large suite of fish species that enter the nation are limited. Evaluating the risk of a species’ invasion in a location is one way to prioritize among many species for management action. Species risk assessments are often associated with information systems or are published within grey literature or peer-reviewed journal articles. Improving access to available risk assessments could help in prioritizing management action for the most potentially invasive fish species. We aggregated fish species risk assessments, synthesizing the current knowledge on the risk of fish invasions in the United States. To accomplish this, we searched information systems and conducted a literature review. We then summarized risk assessment results along with the importation statuses of fish species and identified if imported, high-risk species are managed under federal or state policy. Within the scope of the conterminous U.S., we found 98 high-risk fish species. Eighteen of these species are imported to the country, but only three species have been recently prohibited from importation according to the Lacey Act. We observed similar patterns at the scales of the Great Lakes region and Florida. Collectively, our work provides a baseline estimate of the high-risk fish invaders that enter the U.S. through importation, underscoring species to consider for priority management action, as well as a benchmark of species that lack risk assessments. Insights from this work can be enriched when joined with other invasive species information, which could be accomplished through a national EDRR information system, an information sharing hub in development by the U.S. Geological Survey.

Management of Biological Invasions↗

USGS2008

Land use and the structure of western US stream invertebrate assemblages: Predictive models and ecological traits

Inferences drawn from regional bioassessments could be strengthened by integrating data from different monitoring programs. We combined data from the US Geological Survey National Water-Quality Assessment (NAWQA) program and the US Environmental Protection Agency Wadeable Streams Assessment (WSA) to expand the scope of an existing River InVertebrate Prediction and Classification System (RIVPACS)-type predictive model and to assess the biological condition of streams across the western US in a variety of landuse classes. We used model-derived estimates of taxon-specific probabilities of capture and observed taxon occurrences to identify taxa that were absent from sites where they were predicted to occur (decreasers) and taxa that were present at sites where they were not predicted to occur (increasers). Integration of 87 NAWQA reference sites increased the scope of the existing WSA predictive model to include larger streams and later season sampling. Biological condition at 336 NAWQA test sites was significantly (p < 0.001) associated with basin land use and tended to be lower in basins with intensive landuse modification (e.g., mixed, urban, and agricultural basins) than in basins with relatively undisturbed land use (e.g., forested basins). Of the 437 taxa observed among reference and test sites, 180 (41%) were increasers or decreasers. In general, decreasers had a different set of ecological traits (functional traits or tolerance values) than did increasers. We could predict whether a taxon was a decreaser or an increaser based on just a few traits, e.g., desiccation resistance, timing of larval development, habit, and thermal preference, but we were unable to predict the type of basin land use from trait states present in invertebrate assemblages. Refined characterization of traits might be required before bioassessment data can be used routinely to aid in the diagnoses of the causes of biological impairment. ?? 2008 by The North American Benthological Society.

Arizona, California, Colorado, Idaho, Montana, New↗

USGS2015

Towards a global terrestrial species monitoring program

Introduction: The Convention for Biological Diversity’s (CBD) Strategic Plan for Biodiversity 2011-2020 envisions that “By 2050, biodiversity is valued, conserved, restored and wisely used, maintaining ecosystem services, sustaining a healthy planet and delivering benefits essential for all people.” Although 193 parties have adopted these goals, there is little infrastructure in place to monitor global biodiversity trends. Recent international conservation policy requires such data to be up-to-date, reliable, comparable among sites, relevant, and understandable; as is becoming obvious from the work plan adopted by the Intergovernmental Panel for Biodiversity and Ecosystem Services (IPBES: www.ipbes.net/; http://tinyurl.com/ohdnknq). In order to meet the five strategic goals of the Strategic Plan for Biodiversity 2011-2020 and its 20 accompanying Aichi Targets for 2020 (www.cbd.int/sp/targets/), advances need to be made in coordinating large-scale biodiversity monitoring and linking these with environmental data to develop a comprehensive Global Observation Network, as is the main idea behind GEOSS the Global Earth Observation System of Systems (Christian 2005)...Here we identify ten requirements important for the successful implementation of a global biodiversity monitoring network under the flag of GEO BON and especially a global terrestrial species monitoring program.

Journal for Nature Conservation↗

USGS2016

Assessing condition of macroinvertebrate communities and sediment toxicity in the St. Lawrence River at Massena Area-of-Concern

In 1972, the USA and Canada agreed to restore the chemical, physical, and biological integrity of the Great Lakes ecosystem under the first Great Lakes Water Quality Agreement. In subsequent amendments, part of the St. Lawrence River at Massena, New York and segments of three tributaries, were designated as an Area of Concern (AOC) due to the effects of polychlorinated biphenyls (PCBs), lead and copper contamination, and habitat degradation and resulting impairment to several beneficial uses. Because sediments have been largely remediated, the present study was initiated to evaluate the current status of the benthic macroinvertebrate (benthos) beneficial use impairment (BUI). Benthic macroinvertebrate communities and sediment toxicity tests using Chironomus dilutus were used to test the hypotheses that community condition and sediment toxicity at AOC sites were not significantly different from those of adjacent reference sites. Grain size was found to be the main driver of community composition and macroinvertebrate assemblages, and bioassessment metrics did not differ significantly between AOC and reference sites of the same sediment class. Median growth of C. dilutus and its survival in three of the four river systems did not differ significantly in sediments from AOC and reference sites. Comparable macroinvertebrate assemblages and general lack of toxicity across most AOC and reference sites suggest that the quality of sediments should not significantly impair benthic macroinvertebrate communities in most sites in the St. Lawrence River AOC.

New York↗

USGS2023

Assessing impaired benthic communities using sediment toxicity and contaminant concentrations from reference sites inside the Niagara River Area of Concern

Anthropogenically degraded benthic-macroinvertebrate communities (benthos) are one of seven beneficial use impairments (BUIs) in the Niagara River Area of Concern (AOC). Over the last 50 years, upgrades to waste-water treatment, industry closures, and sediment remediations reduced contaminant levels throughout the system. Improvements in benthic communities and sediment toxicity, however, were difficult to assess because there are no comparable reference reaches outside the AOC. A multi-phase study was initiated in 2015 to determine if data from inside the AOC could identify reference conditions, if toxicity and benthic-community data from these sites differed from other AOC sites, and if further remediation efforts were warranted in parts of the AOC. Concentrations or quotients of PAHs, PCBs, dioxins and furans, pesticides, and most metals were below their New York Sediment Class A Guidance Values at 10 sites that were subsequently designated as reference sites. Survival and growth data from Chironomus dilutus and Hyalella azteca bioassays indicated that sediments from only a few individual AOC-impact sites were toxic or significantly different from reference sites, and that mean toxicity at pooled AOC-impact and reference sites did not differ significantly. Similarly, New York Biological Assessment Profile scores and chironomid mentum deformity scores at only a few individual sites differed significantly from corresponding indices at reference sites, but neither metric differed significantly in comparisons between pooled AOC-impact and reference sites. Most analyses indicated that benthic communities were unimpaired and that removal criteria for the benthos BUI were largely met in much of the upper Niagara River AOC.

New York↗

USGS2023

Assembly of the largest squamate reference genome to date: The western fence lizard, Sceloporus occidentalis

Spiny lizards (genus Sceloporus ) have long served as important systems for studies of behavior, thermal physiology, dietary ecology, vector biology, speciation, and biogeography. The western fence lizard, Sceloporus occidentalis , is found across most of the major biogeographical regions in the western United States and northern Baja California, Mexico, inhabiting a wide range of habitats, from grassland to chaparral to open woodlands. As small ectotherms, Sceloporus lizards are particularly vulnerable to climate change, and S. occidentalis has also become an important system for studying the impacts of land use change and urbanization on small vertebrates. Here, we report a new reference genome assembly for S. occidentalis , as part of the California Conservation Genomics Project (CCGP). Consistent with the reference genomics strategy of the CCGP, we used Pacific Biosciences HiFi long reads and Hi-C chromatin-proximity sequencing technology to produce a de novo assembled genome. The assembly comprises a total of 608 scaffolds spanning 2,856 Mb, has a contig N50 of 18.9 Mb, a scaffold N50 of 98.4 Mb, and BUSCO completeness score of 98.1% based on the tetrapod gene set. This reference genome will be valuable for understanding ecological and evolutionary dynamics in S. occidentalis , the species status of the California endemic island fence lizard ( S. becki ), and the spectacular radiation of Sceloporus lizards.

California↗

USGS2017

Soil microbial community composition is correlated to soil carbon processing along a boreal wetland formation gradient

Climate change is modifying global biogeochemical cycles. Microbial communities play an integral role in soil biogeochemical cycles; knowledge about microbial composition helps provide a mechanistic understanding of these ecosystem-level phenomena. Next generation sequencing approaches were used to investigate changes in microbial functional groups during ecosystem development, in response to climate change, in northern boreal wetlands. A gradient of wetlands that developed following permafrost degradation was used to characterize changes in the soil microbial communities that mediate C cycling: a bog representing an “undisturbed” system with intact permafrost, and a younger bog and an older bog that formed following the disturbance of permafrost thaw. Reference 16S rRNA databases and several diversity indices were used to assess structural differences among these communities, to assess relationships between soil microbial community composition and various environmental variables including redox potential and pH. Rates of potential CO2 and CH4 gas production were quantified to correlate sequence data with gas flux. The abundance of organic C degraders was highest in the youngest bog, suggesting higher rates of microbial processes, including potential CH4 production. In addition, alpha diversity was also highest in the youngest bog, which seemed to be related to a more neutral pH and a lower redox potential. These results could potentially be driven by increased niche differentiation in anaerobic soils. These results suggest that ecosystem structure, which was largely driven by changes in edaphic and plant community characteristics between the “undisturbed” permafrost bog and the two bogs formed following permafrost thaw, strongly influenced microbial function.

European Journal of Soil Biology↗

USGS2017

Assessing condition of macroinvertebrate communities and bed sediment toxicity in the Rochester Embayment Area of Concern, New York, USA

The United States and Canada agreed to restore the chemical, physical, and biological integrity of the Great Lakes ecosystem under the first Great Lakes Water Quality Agreement in 1972. The lowest reach of the Genesee River and the Rochester Embayment on Lake Ontario between Bogus Point and Nine Mile Point, including Braddock Bay, were designated as an Area of Concern (AOC) due to effects of contaminated sediments and physical disturbance on several beneficial uses. Following sediment remedial efforts and with conditions improving in the AOC, the present study was conducted to reevaluate the status of the benthic macroinvertebrate (benthos) beneficial use impairment (BUI). Benthic macroinvertebrate community assessments and 10-day Chironomus dilutus bioassays were used to test the hypotheses that sediments within the AOC were no more toxic than sediments from surrounding reference areas. The study was separated into three discrete systems (Genesee River, Lake Ontario, and Braddock Bay) and non-parametric analyses determined that a multimetric index of benthic macroinvertebrate community integrity was significantly higher at AOC sites compared to reference sites on the Genesee River and in Braddock Bay while AOC and reference sites on Lake Ontario did not differ significantly. Survival and growth of C. dilutus were also similar between AOC and reference sites for each system with the exception of significantly higher growth at reference sites on Lake Ontario. Results generally indicated that the condition of benthos and toxicity of sediment of the Rochester Embayment AOC are similar to or better than that in the surrounding area.

New York↗

USGS2017

Global synthesis of the documented and projected effects of climate change on inland fishes

Although climate change is an important factor affecting inland fishes globally, a comprehensive review of how climate change has impacted and will continue to impact inland fishes worldwide does not currently exist. We conducted an extensive, systematic primary literature review to identify English-language, peer-reviewed journal publications with projected and documented examples of climate change impacts on inland fishes globally. Since the mid-1980s, scientists have projected the effects of climate change on inland fishes, and more recently, documentation of climate change impacts on inland fishes has increased. Of the thousands of title and abstracts reviewed, we selected 624 publications for a full text review: 63 of these publications documented an effect of climate change on inland fishes, while 116 publications projected inland fishes’ response to future climate change. Documented and projected impacts of climate change varied, but several trends emerged including differences between documented and projected impacts of climate change on salmonid abundance ( P = 0.0002). Salmonid abundance decreased in 89.5% of documented effects compared to 35.7% of projected effects, where variable effects were more commonly reported (64.3%). Studies focused on responses of salmonids (61% of total) to climate change in North America and Europe, highlighting major gaps in the literature for taxonomic groups and geographic focus. Elucidating global patterns and identifying knowledge gaps of climate change effects on inland fishes will help managers better anticipate local changes in fish populations and assemblages, resulting in better development of management plans, particularly in systems with little information on climate change effects on fish.

Reviews in Fish Biology and Fisheries↗

USGS2020

Egg and larval collection methods affect spawning adult numbers inferred by pedigree analysis

Analytical methods that incorporate genetic data are increasingly used in monitoring and assessment programs for important rate functions of fish populations (e.g., recruitment). Because gear types vary in efficiencies and effective sampling areas, results from genetic‐based assessments likely differ depending on the sampling gear used to collect genotyped individuals; consequently, management decisions may also be affected by sampling gear. In this study, genetic pedigree analysis conducted on egg and larval Lake Sturgeon Acipenser fulvescens collected from the St. Clair–Detroit River system using three gear types was used to estimate and evaluate gear‐specific differences in the number of spawning adults that produced the eggs and larvae sampled ( N s ), the effective number of breeding adults ( N b ), and individual reproductive success. Combined across locations and sampling years, pooled estimates were 330 ( N s ; point estimate) and 317 ( N b ; 95% CI = 271–372). Mean reproductive success was 4.35 with a variance of 5.33 individuals/spawner. Mean ± SE estimated numbers of unique parents per genotyped egg or larva (i.e., adult detection rate) from 2015 samples were 1.140 ± 0.003 for vertically stratified conical nets, 0.836 ± 0.002 for D‐frame nets, and 0.870 ± 0.002 for egg mats. Using samples from 2016, adult detection rates were 0.823 ± 0.001 for D‐frame nets and 0.708 ± 0.001 for egg mat collections. Coancestry values were negatively correlated with adult detection rate. Although genetic pedigree analyses can improve the understanding of recruitment in fish populations, this study demonstrates that estimates from genetic analyses can vary with the targeted life stage (a biologically informative outcome) and sampling methodology. This study also highlights the influence of sampling methods on the interpretation of genetic pedigree analysis results when multiple gear types are used to collect individuals. Development of standardization approaches may facilitate spatial and temporal comparisons of genetic‐based assessment results.

Michigan, Ontario↗

USGS2011

Engineering a future for amphibians under climate change

1. Altered global climates in the 21st century pose serious threats for biological systems and practical actions are needed to mount a response for species at risk. 2. We identify management actions from across the world and from diverse disciplines that are applicable to minimizing loss of amphibian biodiversity under climate change. Actions were grouped under three thematic areas of intervention: (i) installation of microclimate and microhabitat refuges; (ii) enhancement and restoration of breeding sites; and (iii) manipulation of hydroperiod or water levels at breeding sites. 3. Synthesis and applications. There are currently few meaningful management actions that will tangibly impact the pervasive threat of climate change on amphibians. A host of potentially useful but poorly tested actions could be incorporated into local or regional management plans, programmes and activities for amphibians. Examples include: installation of irrigation sprayers to manipulate water potentials at breeding sites; retention or supplementation of natural and artificial shelters (e.g. logs, cover boards) to reduce desiccation and thermal stress; manipulation of canopy cover over ponds to reduce water temperature; and, creation of hydrologoically diverse wetland habitats capable of supporting larval development under variable rainfall regimes. We encourage researchers and managers to design, test and scale up new initiatives to respond to this emerging crisis.

Journal of Applied Ecology↗