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At least 595 records · Page 33Linked to original sources
USGS1993

How well can fishes prey on zebra mussels in eastern North America?

Literature on mollusk-eating fishes was reviewed to determine the potential for different species of fish to control zebra mussels in eastern North America. At least six species are potential predators of zebra mussels because they possess (1) both upper and lower pharyngeal teeth or (2) lower pharyngeal teeth and chewing pads located on the dorsal roof for crushing mollusk shells. Freshwater drum ( Aplodinotus grunniens ) and two centrarchids, redear sunfish ( Lepomis microlophus ) and pumpkinseed ( L. gibbosus ), possess both upper and lower pharyngeal teeth and are likely to consume more zebra mussels than fishes with only lower pharyngeal teeth. Only two catostomid species, copper and river redhorses ( Moxostoma hubbsi and M. carinatum ), have chewing pads that enable them to crush mollusks. The exotic omnivorous common carp ( Cyprinus carpio ), possessing lower teeth and a chewing pad, may prey on zebra mussels when aquatic insect larvae, its preferred food, become rare. Managing populations of drum, sunfishes and redhorses to reduce exploitation of large individuals and improve their habitats are suggested as means to intensify biological control of zebra mussels in eastern North America. Other Eurasian molluscivores, the roach ( Rutilus rutilus ) and the black carp ( Mylopharyngodon piceus ) should not be introduced into North America because research has shown repeatedly that an introduced biological controller usually does not forage for unwanted pests or reside only in preferred habitats of pests. Drum, sunfishes and redhorses should be preferred over these exotics as biological controllers of zebra mussels in North America because these native fishes will likely occupy newly established habitats of zebra mussels.

Fisheries↗
USGS2003

A new small-eared shrew of the Cryptotis nigrescens-group from Colombia (Mammalia: Soricomorpha: Soricidae)

Cryptotis colombiana Woodman & Timm, 1993 previously was known from few specimens from two isolated regions in the Cordillera Central and Cordillera Oriental of Colombia. Recent collecting in the northern Cordillera Central and review of older collections from the central Cordillera Oriental in the vicinity of Bogota yielded additional specimens that permit reevaluation of the two geographic populations of these small-eared shrews. Morphological and morphometrical studies indicate that the population inhabiting the Cordillera Oriental represents a distinct, previously unrecognized species that I describe herein as Cryptotis brachyonyx. Study of 54 specimens of shrews from the Cordillera Oriental in systematic collections in North America, South America, and Europe yielded only four specimens of the new species, all collected before 1926. The paucity of modern specimens suggests that C. brachyonyx may be extremely restricted in distribution, or possibly extinct.

Proceedings of the Biological Society of Washingto↗
USGS1975

An introduction to the processes, problems, and management of urban lakes

Lakes are bodies of water formed in depressions on the earth's surface, and as such, act as depositories for a variety of chemical and biological materials. The study of lakes has become increasingly prevalent in recent years. Lakes are a valuable resource, and their multiple uses have made them susceptible to water-quality problems such as algal blooms, sediment deposition and fish kills. These problems are products of the eutrophication process (enrichment, aging and extinction of lakes), which is often accelerated by man. Therefore, it becomes important to understand the properties and processes of lakes which govern lake enrichment, and the measures available to control enrichment. Lakes are described in terms of their physical (light penetration, temperature, sediment, and morphology), chemical (chemical constituents, plant nutrients:, and dissolved gases) and biological (plankton, benthos, and nekton) properties. These properties are all interre]ated, and are important variables to measure to evaluate water quality. In addition, lake processes, such as photosynthesis, respiration, eutrophication, and biogeochemical cycling, are important factors in determining the sources and extent of enrichment, and managing a lake for maximum benefit. Meeting demands for water of high quality requires a general knowledge of lake properties and processes, coupled with lake-basin planning, watershed and lake management, and water-quality control. There are many lake-management and control practices, but the best tools for quality control are preventive measures. Once extensive enrichment has occurred, there are few management or control options available. As lake studies become more common, sampling techniques for data collection need increased accuracy and consistency, in order to make meaningful comparisons between different lakes. Therefore, the report discusses the main factors involved in conducting lake studies. These factors include the types and frequency of measurements useful in lake reconnaissance studies and a review of literature on sampling equipment and techniques. A glossary of selected terms begins the report, which is intended for guideline use by urban planners and managers.

Circular↗
USGS2014

A review of pipe and bamboo artificial refugia as sampling tools in anuran studies

Artificial pipe-like refugia have been used for more than 40 years in anuran studies, and have captured 28 species, primarily (82%) hylid treefrogs. Early pipe-like refugia were made using cut pieces of bamboo in the tropical forests of Puerto Rico, but most recent studies have used synthetic pipes and have occurred primarily in the southeastern United States. Characteristics of artificial refugia (e.g., color, length, and diameter), and their placement in the environment have varied greatly among studies, making comparisons difficult. Here, we summarize and evaluate different pipe designs and placement, address potential concerns when using artificial pipe-like refugia, and suggest studies necessary to better interpret the data gained from this technique in anuran studies.

Herpetological Conservation and Biology↗
USGS2007

The state of the art in raptor electrocution research: A global review

We systematically reviewed the raptor electrocution literature to evaluate study designs and methods used in raptor electrocution research, mitigation, and monitoring, emphasizing original research published in English. Specifically, we wondered if three decades of effort to reduce raptor electrocutions has had positive effects. The majority of literature examined came from North America, western Europe, and South Africa. In spite of intensive and often sustained effort by industry and governments across three continents for 30 years, reductions in the incidence of electrocution have been demonstrated in only a few studies. Reliable rate estimates of electrocution mortality generally are unavailable, with some exceptions. Nearly half of 110 studies we analyzed in detail were retrospective reviews of historical mortality records, banding data, or results of necropsies on dead birds received at pathology and veterinary facilities. Among prospective studies, less than half used unbiased approaches to sampling and many did not provide enough detail to assess the sampling design used. At this time, few researchers can demonstrate the reliability of standardized retrofitting procedures or the effectiveness of monitoring techniques. Future progress in reducing raptor mortalities on power lines will benefit from properly designed studies that generate rate estimates of mortality, address biasing factors, and include predictions concerning risk and techniques to reduce risk that can be tested in the field or laboratory.

Biological Conservation↗
USGS2023

A science and management partnership to restore coregonine diversity to the Laurentian Great Lakes

Similar to many freshwater ecosystems, the Laurentian Great Lakes of North America have undergone numerous anthropogenic stressors resulting in considerable loss of biodiversity and habitat. Among Great Lakes fishes, the coregonine sub-family has endured the most extensive declines, including extinction of several species ( Coregonus johannae, C. alpenae , and C. kiyi orientalis ) and at least 10 instances of local extirpations of other species ( C. nigripinnis, C. reighardi, C. zenithicus, C. hoyi , and C. artedi ) across all 5 lakes, much of which occurred prior to the 1960s owing to overfishing, interactions with non-indigenous species, and habitat loss. Despite these declines, no federal-, provincial-, or state-mandated actions were ever implemented to conserve coregonine diversity, potentially because so much of the coregonine declines occurred prior to the enactment of federal conservation legislation. Possible explanations for inaction since enactment of that legislation include insufficient data on biological vulnerability or threats, unresolved taxonomy, and limited support from the fishery management agencies and their stakeholders prior to the 2000s. In recent decades, however, several fishery management agencies have undertaken efforts to re-introduce coregonine diversity. These efforts helped lead to development of a science-based framework to restore coregonines that was universally endorsed by fishery managers representing eight U.S. states, four U.S. tribal organizations, and the province of ON, Canada, in May 2018. The basin-wide framework is based on principles of conservation biology and adaptive management. We describe details of its key steps, including planning, restoring, and evaluating, while also describing recent implementation efforts to develop methods, improve available resources, and enhance coordination across the basin. Although our paper describes a regional effort to restore native coregonines, our adaptive-management approach could be used by other multi-agency stakeholders seeking to conserve or restore native fishes.

Laurentian Great Lakes↗
USGS2026

Applying a metapopulation model to compare native and invasive fish passage scenarios in the Upper Mississippi River

The U.S. Geological Survey assessed the ability of metapopulation models to evaluate population-level effects of fish passage projects in the Upper Mississippi River for six native species: Ictalurus furcatus (Valenciennes in Cuvier and Valenciennes, 1840; blue catfish), Ictiobus cyprinellus (Valenciennes in Cuvier and Valenciennes, 1844; bigmouth buffalo), Acipenser fulvescens (Rafinesque, 1817; lake sturgeon), Polyodon spathula (Walbaum, 1792; American paddlefish [paddlefish]), Ictiobus bubalus (Rafinesque, 1818; smallmouth buffalo), Scaphirhynchus platorynchus (Rafinesque, 1818; shovelnose sturgeon), and one invasive species: Hypophthalmichthys molitrix (Valenciennes in Cuvier and Valenciennes, 1844; silver carp). The study had four objectives: to (1) compile parameter values and identify gaps, (2) parameterize species-specific models, (3) apply the models to multiple scenarios, and (4) develop a point-and-click interface. The literature review revealed a paucity of data, for all species except silver carp and paddlefish; however, length–weight relations, female length–maturity curves, growth curves, spawning and recruitment estimates, and movement data among pools were identified. These data allowed the parameterization of native species metapopulation models, in addition to the use of an existing silver carp model. The models were applied to scenarios representing increased passage, decreased passage, combined passage and deterrents effects, and increased native passage with decreased invasive passage. Increased passage scenarios (depicting potential passage projects) produced greater movement and larger upriver populations. Decreased passage scenarios (depicting potential deterrent projects) yielded reduced movement. Similar population dynamic patterns were observed across species for each scenario because of a lack of species-specific empirical movement data. Simulations for longer lived, slow growing species required longer response times, including time to reach equilibria. A point-and-click model was created to allow others to use the model. Data availability for movement limited the ability of the model to be used to understand fish-movement biology and thereby inform management strategies. More fish-movement data could improve model projections of these scenarios.

Illinois, Iowa, Minnesota, Missouri, Wisconsin↗
USGS2015

Sea-level rise modeling handbook: Resource guide for coastal land managers, engineers, and scientists

Global sea level is rising and may accelerate with continued fossil fuel consumption from industrial and population growth. In 2012, the U.S. Geological Survey conducted more than 30 training and feedback sessions with Federal, State, and nongovernmental organization (NGO) coastal managers and planners across the northern Gulf of Mexico coast to evaluate user needs, potential benefits, current scientific understanding, and utilization of resource aids and modeling tools focused on sea-level rise. In response to the findings from the sessions, this sea-level rise modeling handbook has been designed as a guide to the science and simulation models for understanding the dynamics and impacts of sea-level rise on coastal ecosystems. The review herein of decision-support tools and predictive models was compiled from the training sessions, from online research, and from publications. The purpose of this guide is to describe and categorize the suite of data, methods, and models and their design, structure, and application for hindcasting and forecasting the potential impacts of sea-level rise in coastal ecosystems. The data and models cover a broad spectrum of disciplines involving different designs and scales of spatial and temporal complexity for predicting environmental change and ecosystem response. These data and models have not heretofore been synthesized, nor have appraisals been made of their utility or limitations. Some models are demonstration tools for non-experts, whereas others require more expert capacity to apply for any given park, refuge, or regional application. A simplified tabular context has been developed to list and contrast a host of decision-support tools and models from the ecological, geological, and hydrological perspectives. Criteria were established to distinguish the source, scale, and quality of information input and geographic datasets; physical and biological constraints and relations; datum characteristics of water and land components; utility options for setting sea-level rise and climate change scenarios; and ease or difficulty of storing, displaying, or interpreting model output. Coastal land managers, engineers, and scientists can benefit from this synthesis of tools and models that have been developed for projecting causes and consequences of sea-level change on the landscape and seascape.

Professional Paper↗
USGS1996

Small watershed studies: Analytical approaches for understanding ecosystem response to environmental change

Biogeochemical studies in small watersheds provide an analytical approach to understand how ecosystems respond to natural climatic variations and human-induced environmental change. Small watersheds, usually less than 5 km2, are small enough to permit characterization and understanding of ecosystem processes within relatively simple, homogeneous biological and physical settings; yet they are large enough to incorporate more complex processes and element cycles than can be studied at plot scales. Watersheds comprise discrete hydrochemical environments allowing quantification of hydrologic, element, and energy budgets. Element budgets, or mass balances, can be quantified as the difference between the mass of a solute that enters a watershed in wet and dry deposition and leaves a watershed in streamflow. Element budgets are primary tools used to investigate biogeochemical processes. Monitoring various aspects of element budgets to assess ecosystem health and stability is analogous to measuring the pulse or blood chemistry of a patient. Monitoring streamwater chemistry, basic climate, soil, and biotic variables provide a means to integrate complex biogeochemical processes and evaluate trends in water quality. Small watershed studies provide a scientific basis to develop predictive models of watershed function. Major emphases of small watershed studies include investigation of hydrologic and chemical responses to natural climate variation, anthropogenic stressors, and alternate forest-management practices. The nature and significance of biogeochemical research in small watersheds is reviewed by Moldan and Cerny (1994). The U.S. Geological Survey, U.S. Department of Agriculture Forest Service, and other federal agencies support several long-term small watershed studies to provide insight into a variety of ecosystem processes. Long-term records are essential to distinguish trends resulting from natural climatic variations or other stressors. The following sites, with noted periods of records, are examples of intensively studied forested watersheds in eastern USA supported by federal agencies: ■ Coweeta Hydrologic Laboratory, North Carolina, (1939-present), Swank and Crossley (1988). ■ Hubbard Brook Experimental Forest, New Hampshire, (1956-present), Bormann and Likens (1979). ■ Sleepers River Research Watershed, Vermont, (1958-present), Shanley et al. (1995). ■ Walker Branch Watershed, Tennessee, (1967-present), Johnson and Van Hook (1989). ■ Catoctin Mountains Research Site, Maryland, (1982-present), Rice and Bricker (1995). ■ Catskill Stream Network, New York, (1983- present), Murdoch and Stoddard (1992). ■ Panola Mountain Research Watershed, Georgia, (1985-present), Huntington et al. (1993). Small watershed studies also provide essential baseline information for understanding variations in water quality and element cycling in "pristine" ecosystems that can be used as benchmarks to evaluate anthropogenic impacts and alternate watershed management practices. This paper provides examples of how analytical tools developed through watershed research provide insight into ecosystem processes and can contribute to the management of watershed resources.

Conference Paper↗
USGS2009

A mosaic of diverse ideas: The ecological legacy of J. Frederick Grassle

During the 40 years (and counting) of his scientific career, J. Frederick Grassle has made fundamental contributions to our understanding of marine ecosystems from coral reefs to deep-sea sediments. His advocacy and passion for marine biodiversity in the form of myriad groundbreaking studies and influential reviews, his generosity of ideas and capacity to catalyze and inspire those working with him as well as the science community in general, his breakthroughs in improved ocean observation, his marine science infrastructure initiatives, together with his tireless persistence, have helped lead to major shifts in approaches to marine science and the shape of modern ocean studies to one that favours multidisciplinary research, teamwork, continuous, long-term observation, in situ experimentation, recognition of the importance of marine biodiversity, and global cooperation on research and data sharing. In shallow-water ecology, he co-discovered sibling species of Capitella spp., important not only because it is a key pollution indicator but also because the work helped to pave the way for the discovery of numerous sibling species in other taxa with major ramifications for ecological understanding. He was also a key player in the West Falmouth oil spill study which, along with complementary mesocosm experiments, remains one of the most important and detailed studies of its kind. He was also a lead player in the first biological expedition to hydrothermal vents and wrote the seminal articles that helped to inspire the flurry of vent research that followed. He is perhaps best known for his deep-sea work, where he brought submersibles to the forefront as a sampling tool, brought experimental manipulative studies to the primarily descriptive discipline of deep-sea benthic ecology, and generated tremendous excitement, debate, and rekindled interest in marine biodiversity with the first quantitative estimate of global deep-sea diversity. His efforts to document marine biodiversity resulted in the international Census of Marine Life, and his emphasis on the need for continuous, long-term ocean observation has led to breakthroughs in international cooperation in cabled observatories such as LEO-15. These efforts have also enhanced efforts to integrate ocean data on a global scale in platforms such as the Ocean Biogeographic Information System (OBIS). The diversity of his contributions to marine science mirror the immense marine diversity he has recognized, documented, and championed so effectively over the last four decades.

Deep-Sea Research Part II: Topical Studies in Ocea↗
USGS2017

Synthesis of data from high-frequency nutrient and associated biogeochemical monitoring for the Sacramento–San Joaquin Delta, northern California

Executive Summary This report is the second in a series of three reports that provide information about high-frequency (HF) nutrient and biogeochemical monitoring in the Sacramento–San Joaquin Delta of northern California (Delta). The purpose of this report is to synthesize the data available from a nutrient and water-quality HF (about every 15 minutes) monitoring network operated by the U.S. Geological Survey in the northern Delta. In this report, we describe the network and focus on the purpose of each station. We then present and discuss the available data, at various timescales—first at the monthly, seasonal, and inter-annual timescales, and second, for comparison, at the tidal and event timescales. As expected, we determined that there is substantial variability in nitrate-N concentrations at short timescales within hours, but also significant variability at longer timescales such as months or years. Resolving this variability is made possible by the HF data, with the largest variability caused by storms, tides, and diel biological processes. Given this large temporal variability, calculations of cumulative nutrient fluxes (for example, daily, monthly, or annual loads) is difficult without HF data. For example, in the Cache Slough, calculation of the annual load without the tidal variability resulted in a 30 percent underestimation of the true annual load value. We conclude that HF measurements are important for accurate determination of fluxes and loads in tidal environments, but, more importantly, provide important insights into processes and rates of nutrient cycling. This report, along with the other two reports of this series (Bergamaschi and others, 2017; Kraus, Bergamaschi, and others, 2017), was drafted in cooperation with the Delta Regional Monitoring Program to help scientists, managers, and planners understand how HF data improve our understanding of nutrient sources and sinks, drivers, and effects in the Delta. The first report in the series (Kraus, Bergamaschi, and others, 2017) provides an introduction to the reasons for and fundamental concepts behind using HF monitoring measurements, including a brief summary of nutrient status and trends in the Delta and an extensive literature review showing how and where other research and monitoring programs have used HF monitoring to improve our understanding of nutrient cycling. The report covers the various technologies available for HF nutrient monitoring and presents the different ways HF monitoring instrumentation may be used for fixed station and spatial assessments. Finally, it presents numerous examples of how HF measurements are currently (2017) being used in the Delta to examine how nutrients and nutrient cycling are related to aquatic habitat conditions. The third report in the series (Bergamaschi and others, 2017) provides the background, principles, and considerations for designing an HF nutrient-monitoring network for the Delta to address high-priority, nutrient-management questions. The report starts with discussion of the high‑priority management questions to be addressed, continues through discussion of the questions and considerations that place demands and constraints on network design, discusses the principles applicable to network design, and concludes with the presentation of three example nutrient-monitoring network designs for the Delta, proposed to address high-priority questions identified by the Delta Regional Monitoring Program (Delta Regional Monitoring Program Technical Advisory Committee, 2015).

California↗
USGS2019

Integrating amphibian movement studies across scales better informs conservation decisions

Numerous papers have highlighted the need to integrate amphibian research and conservation across multiple scales. Despite this, most amphibian movement studies focus on a single level of organization (e.g., local population) and a single life stage (e.g., adults) and many suggest potential conservation actions or imply that the information is useful to conservation, yet these presumptions are rarely clarified or tested. Movement studies to date provide little information to guide conservation decisions directly because they fail to integrate movement across scales with individual or population parameters (i.e., fitness metrics); this is exacerbated by a general failure to set movement studies in a probabilistic context. An integrative approach allows prediction of population or metapopulation responses to environmental changes and different management actions, thus directly informing conservation decisions and ‘moving the needle’ towards an informed application of conservation actions. To support this perspective we: 1) revisit reviews of amphibian movement to illustrate the focus on single scales and to underscore the importance of movement – at all scales – to conservation; 2) make the case that movement, breeding, and other demographic probabilities are intertwined and studies executed at different temporal and spatial scales can aid in understanding species' responses to varying environmental and/or management conditions; 3) identify limitations of existing movement-related research to predict conservation action outcomes and inform decision-making; and 4) highlight under-utilized quantitative approaches that facilitate research that either connects movement to fitness metrics (individual-level studies) or estimates population and metapopulation vital rates in addition to, or associated with, movement probabilities.

Biological Conservation↗
USGS2015

Biological and geochemical data along Indian Point, Vermilion Bay, Louisiana

Scientists from the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center collected shallow sediment cores and surface samples from a coastal salt marsh environment next to Vermilion Bay in southwest Louisiana in January 2013. The sampling was part of a larger USGS study to gather data for assessing environmental changes over the past 150 years. The objective of the study was to expand upon the historical context of sea level and storms affecting coastal systems and how these systems might change under persistent or varying conditions. The data from this report add to a regional environmental change database that aids with the continuing effort to understand the evolution of coastal systems. This report serves as an archive for sedimentological, radiochemical, and microbiological data derived from the sediment cores. Data are available for January 2013. Downloadable data are available as Excel spreadsheets and as JPEG files. Additional files include ArcGIS shapefiles of the sampling sites, detailed results of sediment analyses, and formal Federal Geographic Data Committee metadata. Acknowledgments The authors thank Nancy DeWitt, B.J. Reynolds, Christopher Reich (USGS, St. Petersburg Coastal and Marine Science Center), for help with sample collection and processing; Michael Ball, Sarai Piazza, and Gregory Steyer (USGS, Coastal Restoration Assessment Branch) for assistance accessing CRMS Site 541; and Darrell Anders and Phillip Turnipseed (USGS National Wetlands Research Center) for technical support while in the field. We would also like to thank Caitlyn Reynolds and Nicholas Zaremba for their pre-release commentary and peer review. Information Statement This publication was prepared by an agency of the United States Government. Although these data were processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, or for general or scientific purposes, nor shall the act of distribution imply any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and (or) contained herein. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency

Louisiana↗
USGS2017

Review of dynamic optimization methods in renewable natural resource management

In recent years, the applications of dynamic optimization procedures in natural resource management have proliferated. A systematic review of these applications is given in terms of a number of optimization methodologies and natural resource systems. Optimization methods are characterized by (1) the mathematical model used to describe a natural resource system, (2) a set of feasible strategies available to the resource manager, and (3) an objective functional by which to measure benefits and costs of strategies. A formal statement of the control problem is used to describe six approaches to optimal utilization of renewable natural resources: variational mathematics, specifically Pontryagin's Maximum Principle; dynamic programming; linear programming; nonlinear programming; simulation-optimization; and classical procedures. Solution methodologies are illustrated for each of these approaches, and examples from the ecological and natural resource literature are described for various subject matter areas. Applications are highlighted in terms of model structures, objective functionals, and system constraints. To the extent possible, optimal management patterns are characterized. Finally, the applicability of the methods to renewable natural resource systems are compared in terms of system complexity, system size, and precision of the optimal solutions. Recommendations are made concerning the appropriate methods for certain kinds of biological resource problems.

Natural Resource Modeling↗
USGS2011

Performance of fish passage structures at upstream barriers to migration

Attraction and passage efficiency were reviewed and compared from 19 monitoring studies that produced data for evaluations of pool-and-weir, Denil, vertical-slot and nature-like fishways. Data from 26 species of anadromous and potamodromous fishes from six countries were separated by year and taxonomic family into a matrix with 101 records. Attraction performance was highly variable for the following fishway structures: pool-and-weir (attraction range = 29–100%, mean = 77%, median = 81%), vertical-slot (attraction range = 0–100%, mean = 63%, median = 80%), Denil (attraction range = 21–100%, mean = 61%, median = 57%) and nature-like (attraction range = 0–100%, mean = 48%, median = 50%). Mean passage efficiency was inversely related to mean attraction efficiency by fishway structure type, with the highest passage for nature-like fishways (range = 0–100%, mean = 70%, median = 86%), followed by Denil (range = 0–97%, mean = 51%, median = 38%), vertical-slot (range = 0–100%, mean = 45%, median = 43%) and pool-and-weir (range = 0–100%, mean = 40%, median = 34%). Principal components analysis and logistic regression modelling indicated that variation in fish attraction was driven by biological characteristics of the fish that were studied, whereas variation in fish passage was related to fishway type, slope and elevation change. This meta-analysis revealed that the species of fish monitored and structural design of the fishways have strong implications for both attraction and passage performance, and in most cases, existing data are not sufficient to support design recommendations. Many more fishway evaluations are needed over a range of species, fishway types and configurations to characterize, to optimize and to design new fishways. Furthermore, these studies must be performed in a consistent manner to identify the relative contributions of fish attraction and passage to overall fishway performance at each site.

River Research and Applications↗
USGS2012

Enhanced surveillance strategies for detecting and monitoring chronic wasting disease in free-ranging cervids

The purpose of this document is to provide wildlife management agencies with the foundation upon which they can build scientifically rigorous and cost-effective surveillance and monitoring programs for chronic wasting disease (CWD) or refine their existing programs. The first chapter provides an overview of potential demographic and spatial risk factors of susceptible wildlife populations that may be exploited for CWD surveillance and monitoring. The information contained in this chapter explores historic as well as recent developments in our understanding of CWD disease dynamics. It also contains many literature references for readers who may desire a more thorough review of the topics or CWD in general. The second chapter examines methods for enhancing efforts to detect CWD on the landscape where it is not presently known to exist and focuses on the efficiency and cost-effectiveness of the surveillance program. Specifically, it describes the means of exploiting current knowledge of demographic and spatial risk factors, as described in the first chapter, through a two-stage surveillance scheme that utilizes traditional design-based sampling approaches and novel statistical methods to incorporate information about the attributes of the landscape, environment, populations and individual animals into CWD surveillance activities. By accounting for these attributes, efficiencies can be gained and cost-savings can be realized. The final chapter is unique in relation to the first two chapters. Its focus is on designing programs to monitor CWD once it is discovered within a jurisdiction. Unlike the prior chapters that are more detailed or prescriptive, this chapter by design is considerably more general because providing comprehensive direction for creating monitoring programs for jurisdictions without consideration of their monitoring goals, sociopolitical constraints, or their biological systems, is not possible. Therefore, the authors draw upon their collective experiences implementing disease-monitoring programs to present the important questions to consider, potential tools, and various strategies for those wildlife management agencies endeavoring to create or maintain a CWD monitoring program. Its intent is to aid readers in creating efficient and cost-effective monitoring programs, while avoiding potential pitfalls. It is hoped that these three chapters will be useful tools for wildlife managers struggling to implement efficient and effective CWD disease management programs.

Open-File Report↗
USGS2016

A review of the relationships between drought and forest fire in the United States

The historical and pre-settlement relationships between drought and wildfire are well documented in North America, with forest fire occurrence and area clearly increasing in response to drought. There is also evidence that drought interacts with other controls (forest productivity, topography, fire weather, management activities) to affect fire intensity, severity, extent, and frequency. Fire regime characteristics arise across many individual fires at a variety of spatial and temporal scales, so both weather and climate—including short- and long-term droughts—are important and influence several, but not all, aspects of fire regimes. We review relationships between drought and fire regimes in United States forests, fire-related drought metrics and expected changes in fire risk, and implications for fire management under climate change. Collectively, this points to a conceptual model of fire on real landscapes: fire regimes, and how they change through time, are products of fuels and how other factors affect their availability (abundance, arrangement, continuity) and flammability (moisture, chemical composition). Climate, management, and land use all affect availability, flammability, and probability of ignition differently in different parts of North America. From a fire ecology perspective, the concept of drought varies with scale, application, scientific or management objective, and ecosystem.

Global Change Biology↗