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Introduction to special section: The Trans-Alaska Crustal Transect (TACT) across Arctic Alaska

This special section of the Journal of Geophysical Research addresses the composition and structural evolution of the lithosphere in northern Alaska. Investigations reported in this section were mainly undertaken as part of the Trans‐Alaska Crustal Transect (TACT), an integrated geological and geophysical transect of the entire Alaskan lithosphere along a north‐south corridor undertaken from 1984 to 1992 (Figure 1). The onshore segment of the transect approximately follows along the route of the trans‐Alaskan pipeline; the offshore segment extends across the continental margin in the Gulf of Alaska to the Pacific plate. The TACT line is unique in that it provides a coordinated onshore/offshore geological and geophysical traverse of the North American plate in Alaska from the active convergent Pacific margin to the passive Arctic margin of the continent.

Alaska↗

Purpose, processes, partnerships, and products: four Ps to advance participatory socio-environmental modeling

Including stakeholders in environmental model building and analysis is an increasingly popular approach to understanding ecological change. This is because stakeholders often hold valuable knowledge about socio-environmental dynamics and collaborative forms of modeling produce important boundary objects used to collectively reason about environmental problems. Although the number of participatory modeling (PM) case studies and the number of researchers adopting these approaches has grown in recent years, the lack of standardized reporting and limited reproducibility have prevented PM's establishment and advancement as a cohesive field of study. We suggest a four-dimensional framework (4P) that includes reporting on dimensions of (1) the Purpose for selecting a PM approach (the why ); (2) the Process by which the public was involved in model building or evaluation (the how ); (3) the Partnerships formed (the who ); and (4) the Products that resulted from these efforts (the what ). We highlight four case studies that use common PM software-based approaches (fuzzy cognitive mapping, agent-based modeling, system dynamics, and participatory geospatial modeling) to understand human–environment interactions and the consequences of ecological changes, including bushmeat hunting in Tanzania and Cameroon, agricultural production and deforestation in Zambia, and groundwater management in India. We demonstrate how standardizing communication about PM case studies can lead to innovation and new insights about model-based reasoning in support of ecological policy development. We suggest that our 4P framework and reporting approach provides a way for new hypotheses to be identified and tested in the growing field of PM.

Ecological Applications↗

A survey of the indigenous microbiota (bacteria) in three species of mussels from the Clinch and Holston Rivers, Virginia

Freshwater mussel conservation efforts by many federal and state agencies have increased in recent years. This has led to a greater number of stream surveys, in which mussel die-offs involving high numbers of dead and moribund animals are being observed and reported with greater frequency. Typically, die-offs have been incidentally observed while research was being done for other purposes, therefore, accurate mortality data have been difficult to obtain. Specifically, seasonal die-offs were noted in localized areas of the Clinch and Holston Rivers, Virginia, and to lesser degrees, in neighboring rivers in this geographic region, including southeast Virginia. The observed mussel species affected were primarily the slabside pearlymussel ( Lexingtonia dolabelloides ) and to lesser extents, the pheasantshell ( Actinonaias pectorosa ), rainbow mussel ( Villosa iris ), and the endangered shiny pigtoe ( Fusconaia cor ). To determine if a bacterial pathogen might be involved in these recurring mussel die-offs, this study examined characteristics of the indigenous microbiota (bacteria) from healthy mussels from sites on the Clinch and Holston Rivers where die-offs were previously observed. These baseline data will allow for recognition of bacterial pathogens in future mussel die-offs. Means for total bacteria from soft tissues ranged from 1.77 × 10 5 to 3.55 × 10 6 cfu/g; whereas, the range in means from fluids was 2.92 × 10 4 to 8.60 × 10 5 cfu/mL. A diverse microbiota were recovered, including species that are common in freshwater aquatic environments. The most common bacterial groups recovered were motile Aeromonas spp. and nonfermenting bacteria. Flavobacterium columnare , a pathogen to cool- and warm-water fishes was recovered from one specimen, a Villosa iris from the Clinch River.

Virginia↗

Annual compilation and analysis of hydrologic data for urban studies in the Bryan, Texas, metropolitan area, 1969

Hydrologic investigations of urban areas in Texas were begun by the U.S. Geological Survey in 1954. These studies are now in progress in Austin, Houston, Dallas, Dallas County, Fort Worth, San Antonio, and Bryan. Hydrologic investigations of urban areas in Texas were begun by the U.S. Geological Survey in 1954. These studies are now in progress in Austin, Houston, Dallas, Dallas County, Fort Worth, San Antonio, and Bryan. 1. To determine, on the basis of historical data and hydrologic analyses, the magnitude and frequency of floods. 2. To document and define the areal extent of floods of greater than ordinary magnitude. 3. To determine the effect of urban development on flood peaks and volume. 4. To provide applied research facilities for studies at Texas A & M University at College Stations. This report, the first in a series of reports to be published annually, is primarily applicable to objectives 2, 3, and 4. The report presents the basic hydrologic data collected in two study areas during the 1969 water year (October 1, 1968, to September 30, 1969) and basic hydrologic data collected during part of the 1968 water year (April 5, 1968, to September 30, 1968). The locations of the two basins within the study area, Burton Creek and Hudson Creek, are shown on figure 1.

Texas↗

Estimating occurrence, prevalence, and detection of amphibian pathogens: Insights from occupancy models

Understanding the distribution of pathogens across landscapes and their prevalence within host populations is a common aim of wildlife managers. Despite the need for unbiased estimates of pathogen occurrence and prevalence for planning effective management interventions, many researchers fail to account for imperfect pathogen detection. Instead raw data are often reported, which may lead to ineffective, or even detrimental, management actions. We illustrate the utility of occupancy models for generating unbiased estimates of disease parameters by 1) providing a written tutorial describing how to fit these models in Program PRESENCE and 2) presenting a case study with the pathogen ranavirus. We analyzed ranavirus detection data from a wildlife refuge (Maryland, US) using occupancy modeling, which yields unbiased estimates of pathogen occurrence and prevalence. We found ranavirus prevalence was underestimated by up to 30% if imperfect pathogen detection was ignored. The unbiased estimate of ranavirus prevalence in larval wood frog ( Lithobates sylvaticus ; 0.73) populations was higher than in larval spotted salamander ( Ambystoma maculatum ; 0.56) populations. In addition, the odds of detecting ranavirus in tail samples were 6.7 times higher than detecting ranavirus in liver samples. Therefore, tail samples presented a nonlethal sampling method for ranavirus that may be able to detect early (nonsystemic) infections.

Maryland↗

Annotated bibliography of scientific research on Ventenata dubia published from 2010 to 2020

Integrating recent science into management decisions supports effective natural resource management and can lead to better resource outcomes. However, finding and accessing science information can be time consuming and costly. To assist in this process, the U.S. Geological Survey (USGS) is creating a series of annotated bibliographies on topics of management concern for western lands. Previously published reports introduced a methodology for preparing annotated bibliographies to facilitate the integration of recent, peer-reviewed science into resource management decisions. Therefore, relevant text from those efforts is reproduced here to frame the presentation. Invasive annual grasses are widely distributed throughout the western United States and threaten native ecosystems by altering fire regimes, replacing native plants, and altering grazing patterns, often with tremendous associated costs. One invasive annual grass, Ventenata dubia (hereafter, ventenata), was first introduced to the United States in the 1950s and has recently been identified as a management concern. Ventenata has a wide native geographic range, from Africa to northern Europe, and could thus potentially spread widely in the United States if left unmanaged. We compiled and summarized peer-reviewed journal articles, government reports, and data products on ventenata published between January 1, 2010, and August 27, 2020. We first conducted a systematic search of three reference databases and three government databases using the search phrase: “ventenata” OR “Ventenata dubia.” We refined the initial list of products by removing (1) duplicates, (2) products not written in English, (3) publications that were not focused in North America, (4) publications that were not published as research, data products, or scientific review articles in peer-reviewed journals or as formal technical reports, and (5) products for which ventenata was not a research focus or for which the study did not present new data or findings about ventenata. We summarized each product using a consistent structure (background, objectives, methods, location, findings, and implications) and identified the management topics (for example, species and population characteristics, habitat, control and management efforts) addressed by each product. We also noted which publications included new geospatial data. The review process for this annotated bibliography included an initial internal colleague review of each summary, requesting input on each summary from an author of the original publication, and a formal peer review. Our initial searches resulted in 505 total products, of which 29 met our criteria for inclusion. Nonnative invasive plants; weed management; behavior or demographics; dispersal, spread, vectors and pathways; site-scale habitat characteristics; survival; and weed management subtopic: herbicides were the management topics most commonly addressed. The online version of this annotated bibliography will be searchable by topic, location, and year; it will also include links to each original publication, where available. The studies compiled and summarized here may inform planning and management actions that seek to maintain and restore landscapes and control nonnative invasive species across the western United States.

Open-File Report↗

Analytical methods of the U.S. Geological Survey's New York District Water-Analysis Laboratory

The New York District of the U.S. Geological Survey (USGS) in Troy, N.Y., operates a water-analysis laboratory for USGS watershed-research projects in the Northeast that require analyses of precipitation and of dilute surface water and soil water for major ions; it also provides analyses of certain chemical constituents in soils and soil gas samples. This report presents the methods for chemical analyses of water samples, soil-water samples, and soil-gas samples collected in wateshed-research projects. The introduction describes the general materials and technicques for each method and explains the USGS quality-assurance program and data-management procedures; it also explains the use of cross reference to the three most commonly used methods manuals for analysis of dilute waters. The body of the report describes the analytical procedures for (1) solution analysis, (2) soil analysis, and (3) soil-gas analysis. The methods are presented in alphabetical order by constituent. The method for each constituent is preceded by (1) reference codes for pertinent sections of the three manuals mentioned above, (2) a list of the method's applications, and (3) a summary of the procedure. The methods section for each constitutent contains the following categories: instrumentation and equipment, sample preservation and storage, reagents and standards, analytical procedures, quality control, maintenance, interferences, safety considerations, and references. Sufficient information is presented for each method to allow the resulting data to be appropriately used in environmental investigations.

Open-File Report↗