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At least 739 records · Page 41Linked to original sources
USGS2024

Distribution of yellow crazy ants (Anoplolepis gracilipes) and notes on other ant species at Wake Atoll, 6-21 October, 2023

Wake Atoll, located in the central Pacific Ocean, is a tropical coral atoll comprised of three islands totaling 696 ha of emergent land. Wake Atoll supports at least 17 species of non-native ants, but one species, the yellow crazy ant ( Anoplolepis gracilipes ), is especially harmful to ecosystems, including seabirds, which are federally protected species and nest throughout Wake Atoll. Our objective was to map the distribution of yellow crazy ants (YCA) across Wake Atoll to provide U.S. Air Force managers with information that could inform an eradication strategy for this species. In addition, we documented the presence of other ant species identified during our survey. We used a 50 x 50-m cell-based sampling grid to survey for YCA and other ant species. YCA were widespread across the atoll, occupying all three islands and were detected in 566 of the 3,675 (15.4%) cells surveyed, covering an area of about 142 ha. The highest proportion of cells containing YCA was on Wilkes Island (99 of 400 cells or 24.8%), followed by Wake Island (395 of 2,760 cells or 14.3%) and Peale Island (72 of 518 cells or 14.0%). YCA detections on Wilkes Island were restricted to Wilkes South (99 of 202 cells or 49.0%); no YCA were found on Wilkes North, an important area that supports the most diverse assemblage of nesting seabirds on Wake Atoll. Based on technologies developed to eradicate YCA from Johnston Atoll and elsewhere, eradicating YCA from Wake Atoll appears technically feasible. The occurrence of discrete populations (i.e., clusters of occupied cells separated from other clusters of occupied cells) within and among islands could allow a stepwise strategy where the short-term outcome of the treatment of one population is independent of the outcome of another treatment. Without action, the high-density YCA population on Wilkes South could breach the narrow (~50 m), sometimes dry, channel separating Wilkes North and South, posing a serious threat to nesting seabirds present on Wilkes North. Eradicating YCA from Wilkes South would create a buffer from YCA and reduce the threat of northward movement of YCA. We also detected 12 ant species other than YCA during our survey, including Lepisiota frauenfeldi , a new record for the atoll.

Hawaii Cooperative Studies Unit Technical Report↗
USGS2024

Distribution and trends of endemic Hawaiian waterbirds, 1986–2023

This study updates the status assessment of four endemic endangered Hawaiian waterbird species—ae‘o (Hawaiian stilt, Himantopus mexicanus knudseni), ‘alae ke‘oke‘o (Hawaiian coot, Fulica alai), ‘alae ‘ula (Hawaiian gallinule, Gallinula galeata sandvicensis), and koloa maoli (Hawaiian duck, Anas wyvilliana)—from 1986 to 2016 by incorporating new data from 2017–2023. State-space models, which account for biological and sampling variation, were fitted to estimate population sizes and trends from both core and non-core wetland survey sites. Long-term trends (1986–2023) largely show increasing populations for all four species, but recent short-term trajectories (2013–2023) are to a greater degree than previous analyses, predominantly negative, indicating accentuated declines in some island populations. Summer counts have declined relative to winter counts over the 38-year period, indicating potential changes in habitat availability and breeding patterns due to shifting rainfall patterns. Although negative trends were apparent in some non-core wetlands, our study underscores the importance of both core and non-core wetlands for waterbird populations.

Hawaii↗
USGS2025

Wake Atoll: Evaluation of plant biosecurity

Introduced organisms can cause substantial effects across most landscapes. Island ecosystems, especially tropical islands, are at elevated risk from introduced organisms. The risks are even higher for tropical islands with moderate or high levels of transit, yet this can be minimized by application of appropriate biosecurity requirements. In this study, we examined the potential for non-native plant species introductions, especially invasive plants, via shipping containers to be transported to Wake Atoll, one of the most remote terrestrial land masses in the Pacific Ocean. We sowed debris collected from 30 shipping containers in a greenhouse experiment to determine if any live plants could be germinated, identify any species that germinated, and ascertain if they posed a threat if they were to be transported to Wake Atoll and became established there. During this study 23 plant species were identified, including ferns, monocots, and dicots. Fifteen of these species reached reproductive maturity over the course of seven months. From previous plant surveys on the atoll, we know that 13 of the 23 identified species were not previously recorded, and four species are already known to be invasive on Wake Atoll. This study provides insight into the potential for debris found in shipping containers to contribute to the spread of non-native, possibly invasive species. This information may help with the refinement of biosecurity strategies to prevent the accidental introduction of invasive species into sensitive natural areas such as Wake Atoll.

Hawaii Cooperative Studies Unit Technical Report↗
USGS2025

Status and trends of forest bird populations at Hakalau Forest National Wildlife Refuge, 1987–2024

Since 1985, the Hakalau Forest Unit of the Big Island National Wildlife Refuge Complex (hereafter, Hakalau) has protected the largest endemic forest bird diversity in the State of Hawaii. This includes three endangered and one threatened species and their habitats. Hakalau’s vast area (155 km2), mostly high elevation (>1500 m) montane forest, provides refuge from avian malaria (Plasmodium relictum) vectored by introduced southern house mosquitoes (Culex quinquefasciatus). However, increases in the seasonal temperatures optimal for disease carrying mosquitoes associated with climate change have coincided with recent downward trends of native species in the closed forest area of the refuge (1450–1750 m), where disease is most likely to occur. Therefore, to inform refuge management with the most updated information on these populations and their trends, we analyzed forest bird survey data collected using point transect distance sampling with new survey data from 2021–2024. We stratified our analysis across management units, including the open forest and pasture since 1987, and the closed forest since 1999, and across four elevation ranges (<1500, 1500–1700, 1700–1900, and >1900 m) since 1999. We used distance sampling to estimate species- and strata-specific abundances and applied log-linear regression to detect trends across the timeseries. We found a continuation of previous trends, wherein most native forest birds declined in the closed forest strata (mostly below 1700 m) and increased in the highest elevation and pasture strata. Patterns were highly species-specific for the three lower elevations and open forest strata. ‘Apapane (Himatione sanguinea) and warbling white-eye (Zosterops japonicus), the most abundant native and introduced bird species, respectively, increased in nearly all strata. ‘I‘iwi (Drepanis coccinea) and Hawai‘i ‘amakihi (Chlorodrepanis virens virens), also common, decreased in closed forest, were stable in open forest, and increased in pasture. Both species were generally stable or increasing across all elevation bands, except Hawaiʻi ʻamakihi decreased in the below 1500 m and the 1500–1700 m elevation bands. All three of the federally endangered forest bird species declined in closed forest. Hawai‘i ‘ākepa (Loxops coccineus) also declined in the open forest and 1700–1900 m band and was the only species to decline overall. ‘Akiapōlā‘au (Hemignathus wilsoni) declined in closed forest but increased overall. ‘Alawī (Loxops mana, also known as Hawai‘i creeper) also decreased in the closed forest, but was stable to increasing in most strata and remained stable overall. Hawaiʻi ʻelepaio (Chasiempis sandwichensis) declined in closed forest, was stable in open forest and most elevation strata, and increased in pasture. ʻŌmaʻo (Myadestes obscurus) was stable in open and closed forest and at middle elevations and increased in the pasture. Introduced red-billedleiothrix (Leiothrix lutea) declined in closed forest, was stable in the open forest and at most elevations, and increased in the pasture. Coinciding with these changes, seasonal conditions for vector occurrence have continued to lengthen in the lower elevation strata through 2024, while Hakalau’s outplanting efforts continued to increase forest cover in the pasture, suggesting that disease-free habitat may have decreased in the closed forest and increased in the pasture. The declines in the closed forest and mixture of trends in the open forest and middle elevations bands suggest emigration into the higher elevation strata from lower elevation strata, and that possible threats have suppressed forest birds even at elevations >1500 m.

Hawaii↗
USGS2024

Assessing habitat use and population dynamics of fisheries resources at Kaloko Fishpond

Throughout Hawai'i, fishponds are considered by their local communities as important cultural touchstones, a source of local, sustainably produced food, and an important component to the development of community-based management for nearshore fisheries. Within Kaloko-Honokōhau National Historical Park, the restoration of Kaloko Fishpond for traditional aquaculture management is a goal of both the National Park Service (NPS) and Hui Kaloko-Honokōhau, a community-based group of kia'i, i.e., caretakers and native Hawaiian cultural practitioners. However, existing data on the demographics and condition of the fish populations within the pond, and the fish-habitat quality are poor to non-existent. Therefore, the objectives of this study were to: catalog fish species composition and distribution in the pond; estimate the abundance of focal species/taxonomic groups; and evaluate the occupancy patterns of the invasive algae Acanthophora spicifera and Upside-down Jellyfish Cassiopea andromeda. As part of these objectives, a survey protocol and analysis framework were designed and evaluated to ensure that the NPS and community group would be able to refine and implement them to continue their monitoring efforts. We conducted dual-observer shore-based visual surveys multiple times per week during September-October 2020 and April-September 2022. A total of 41 species/taxonomic groups were recorded over the course of the surveys. The largest number of species/taxonomic groups were observed at survey stations located on or near the kuapā, or wall separating the fishpond from the ocean. N-mixture models fitted to the data estimated a total population of 353 – 392 mullets, 134 – 192 flagtails (āholehole), and 189 – 277 Milkfish (Awa) Chanos chanos occurring within the 1.2-ha portion of Kaloko Fishpond that could be surveyed visually from the shoreline. Multi-season occupancy models fitted to the surveyed presence of A. spicifera and Upside-down Jellyfish indicted sites throughout most of the pond exhibited moderate and consistent occupancy (ψ = 0.30 – 0.40) throughout much of the pond, except for the northeast corner of the pond (Kaloko Iki) where colonization rates were lower and extinction rates higher than other areas within Kaloko. The visual survey method developed for this study provides a low-cost and effective starting point for the development of methodology that can be used both by NPS personnel and volunteers from the community group. However, we were only able to estimate fish populations for approximately 24% of the area of Kaloko Fishpond with this method. Given that the deeper areas of Kaloko Fishpond are completely inaccessible to the visual survey method used, generating population estimates for the entire pond based on the parameters estimated in the current study is not recommended without further investigation into fish movement and habitat use. Various means to refine this protocol to better meet the needs and abilities of the NPS and community group are proposed.

Hawaii↗
USGS2025

Improving efficiency of disease vector sampling in the field: An automatic solar-powered mosquito trapping system

Trapping mosquitoes to quantify their distribution and abundance is often a key step in monitoring dynamics of vector-borne diseases. This is the case in Hawaii, where avian malaria is devastating native forest birds that are highly susceptible to non-native diseases. However, mosquito trapping is difficult and labor intensive. A typical operation requires traps to be visited multiple times within a 24-hour period to control their active components and batteries. For example, traps for nocturnal mosquitoes require trap fans and carbon dioxide (CO2) tanks turned on in the evening and then turned off the following morning, with batteries changed frequently. For traps in very remote locations, this frequent attendance accrues considerable cost and personnel time. To help minimize field efforts required for maintaining mosquito trapping arrays, we developed an automated power system to operate the mosquito traps. The traps can be set to operate on a schedule using a built-in timer, eliminating the need for personnel to manually turn traps on and off. Additionally, this system is powered by a solar-recharged battery so that the system can run indefinitely in many field locations. We tested the system at ‘Āinahou Ranch in Hawai‘i Volcanoes National Park, Island of Hawai‘i, where we operated a trapping array continuously for over two years. Specifically, two types of traps were deployed at each location, one a gravid trap and another a CO2 trap. We provide a step-by-step guide on how to build the systems and describe how to deploy them in the field.

Hawaii Cooperative Studies Unit Technical Report↗
USGS2025

Evolution of permeability and strength recovery of shear fracture under hydrothermal conditions

Geothermal energy is a clean and renewable resource that depends on the ability to move water through hot rock. In many locations, the ability to move water through rock requires the presence of extensive natural or human-made systems of fractures. However, these fracture systems are influenced by a variety of complex processes that occur at the temperature and pressure conditions found in geothermal reservoirs. To make geothermal systems more efficient, it is important to understand how these fractures evolve over time in response to these processes. This study explored how fractures in rock change under high-temperature and pressure conditions, like those found in geothermal reservoirs, through laboratory experiments and numerical simulations. In general fractures, tend to close due to pressure from the surrounding rock preventing the flow of water. One set of laboratory experiments revealed that fractures in granitic rock can weaken over time at elevated temperatures. These weak fractures can then slip slowly potentially keeping the fracture open for a longer period. This study also showed that at the highest temperature examined (250 °C) large differences between the chemical composition of the rock and the fluid moving through it could improve water flow temporarily likely due to the water dissolving parts of the rock. Flow rate predicted by models shows overall good agreement with the flow rate measured in our experiments but with some long time-scale variations that may be due to mechanical wear of the fracture surface. A second set of experiments found that, over the temperature range examined, the closure of fractures was caused by brittle failure driven by high stresses at points where fracture surfaces were in contact. This result suggests that fracture closure in geothermal reservoirs could be counteracted by maintaining high pore pressures. Additionally, we also tested a new method using electrical resistance to measure fracture closure in controlled systems with high precision.

Final Technical Report↗
USGS2026

Avoiding common pitfalls in the implementation of adaptive forest wildlife management

Forest management planning requires the evaluation of tradeoffs in proposed management actions to meet multiple objectives, including providing the habitat required to sustain wildlife populations. However, various species-specific life history strategies and ecological uncertainties complicate our understanding of the responses of wildlife to disturbances, such as wildfires and forest management. We believe that adaptive management processes, applied through the close collaboration of researchers and managers (e.g., coproduction), will be valuable in this effort. Although adaptive management programs have been touted in the past, we stress that many of these programs have fallen short of the requisite steps to complete the learning cycles of this process (i.e., single- and double-loop learning). Thus, we provide guidance on what we believe to be the missing components of these efforts in hopes to guide future coordination of local and regional adaptive management programs for forest wildlife.

General Technical Report↗
USGS2025

Stream gauge network assessment

The purpose of this chapter is to assess the current (2023) performance and capabilities of the streamgauge network installed for the “Evaluate Improved Streamflow Measurement Technologies at TxDOT Bridges” project. The U.S. Geological Survey (USGS) traditionally employs a method of discharge computation relating continuously measured stage to an associated discharge (Rantz and others, 1982). This stage-discharge relation is built using numerous physical discharge measurements, which is labor-intensive. A primary research objective of this project is to evaluate the feasibility of methods alternative to the traditional USGS stage-discharge relation for computing discharge, namely the computation of discharge using surface velocimetry.

Texas↗
USGS2024

Evaluation of fish passage for assessment of invasive carp deterrents at locks in the upper Mississippi River

Invasive carps are established in the upper, middle, and lower Mississippi River and their expansion upstream threatens a variety of aquatic ecosystem services including fishing and recreational boating. The physical and operational characteristics of Lock and Dam (LD) 19 restrict upstream movement of fishes because the only upstream fish passage route is through the lock chamber. This restriction might be hindering consistent reproduction and recruitment of invasive carps enough to reduce their abundance upstream from LD 19. Locks and Dams 5, 14, and 15 (upriver from LD 19) are infrequently at open-condition and may also be limiting the continued upstream expansion of invasive carps. Upstream passage of fishes at these locations would be limited to the lock chamber for the majority of the year (Wilcox et al. 2004; Bouska 2021).

Illinois, Iowa, Minnesota, Missouri, Wisconsin↗
USGS2026

An evaluation of next-generation biological control methods for the invasive brown treesnake in the Mariana Islands

The brown treesnake (BTS) invasion in Guam continues to cause extensive ecological and economic damage, yet existing control tools cannot achieve islandwide suppression or eradication, highlighting the need for new strategies. This review evaluates the feasibility of classical and genetic biocontrol approaches for BTS and identifies priority knowledge gaps. Classical biocontrol, which relies on pathogens or parasites from a pest’s native range, has had limited success in vertebrates, though certain viruses may hold potential. For BTS, prior work has identified candidate agents, including hemogregarines and paramyxoviruses, but major uncertainties remain in transmission, specificity, long term efficacy, and ecological risk. Theoretical models suggest that moderately virulent pathogens may offer the strongest potential for sustained suppression, with Ophidian paramyxoviruses emerging as a leading prospect, though substantial empirical research is still required. Genetic biocontrol offers additional possibilities, including gene drives that could bias inheritance, reduce fertility, or skew sex ratios. Self sustaining homing and shredding drives could theoretically produce long term reductions, while “enhanced” self limiting systems may provide geographically restricted alternatives. Approaches involving genetically modified prey and toxic males that shorten female lifespan through mating may have future relevance but require major development and validation. Risks across genetic strategies include unintended spread, ecological side effects, technical constraints such as producing engineered snakes, potential resistance, and regulatory complexity. Because feasibility depends on societal acceptance, the review emphasizes the need for early engagement with Guam’s local and Indigenous communities, whose perspectives will shape future development and implementation. Key research priorities include improved modeling, native range genomic characterization of BTS, expanded pathogen surveys, advances in BTS genetic tools and captive rearing methods, and further exploration of both classical pathogen candidates and genetically engineered prey systems. Collectively, the review concludes that classical and genetic biocontrol hold promise for long term, cost effective BTS suppression, but substantial scientific, ethical, ecological, and social groundwork remains before deployment.

Hawai’i Cooperative Fishery Research Unit Technica↗
USGS2002

Cascading effects of fire exclusion in Rocky Mountain ecosystems: A literature review

The health of many Rocky Mountain ecosystems is in decline because of the policy of excluding fire in the management of these ecosystems. Fire exclusion has actually made it more difficult to fight fires, and this poses greater risks to the people who fight fires and for those who live in and around Rocky Mountain forests and rangelands. This paper discusses the extent of fire exclusion in the Rocky Mountains, then details the diverse and cascading effects of suppressing fires in the Rocky Mountain landscape by spatial scale, ecosystem characteristic, and vegetation type. Also discussed are the varied effects of fire exclusion on some important, keystone ecosystems and human concerns.

U.S. Forest Service General Technical Report↗
USGS1996

Review of USGS Open-file Report 95-525 ("Cartographic and digital standard for geologic map information") and plans for development of Federal draft standards for geologic map information

This report summarizes a technical review of USGS Open-File Report 95-525, 'Cartographic and Digital Standard for Geologic Map Information' and OFR 95-526 (diskettes containing digital representations of the standard symbols). If you are considering the purchase or use of those documents, you should read this report first. For some purposes, OFR 95-525 (the printed document) will prove to be an excellent resource. However, technical review identified significant problems with the two documents that will be addressed by various Federal and State committees composed of geologists and cartographers, as noted below. Therefore, the 2-year review period noted in OFR 95-525 is no longer applicable. Until those problems are resolved and formal standards are issued, you may consult the following World-Wide Web (WWW) site which contains information about development of geologic map standards: URL: http://ncgmp.usgs.gov/ngmdbproject/home.html

Open-File Report↗
USGS1992

XDETECT version 2.01 technical reference

This report is oriented toward the 'C' language programmer who is interested in the details of XDETECT version 2.01 operation. (In addition certain details of XDETECT version 2.03 are also discussed.) This interest might stem from the need to modify or add to the program. Users of XDETECT should also refer to the user's guide (Tottingham, 1990).

Open-File Report↗
USGS1994

Hydrologic Instrumentation Facility of the U.S. Geological Survey, annual report for fiscal year 1993

The Hydrologic lnstrumentation Facility (HIF) of the U.S. Geological Survey (USGS) has nationwide responsibility for all aspects of hydrologic field instrumentation in support of Survey data-collection programs. Each year the HIF publishes a report to inform Water Resources Division (WRD) personnel of progress made by the HIF in fulfilling its mission to improve instrumentation services to the Division. The report for fiscal year 1993 (FY93) describes the activities of the HIF, including major accomplish- ments for the year; personnel actions; active projects (reported by section--Technical Services Section, Administrative Services Section, Field Coordination, Applications and Development Section, Test and Evaluation Section, Field Service and Supply Section); and planned activities for the coming year. Also presented in the appendixes are detailed listings of the memberships of the Instrumentation Committee and the Instrumentation Technical Advisory Subcommittee; district, sub- district, and field office visits by HIF personnel; professional and technical meetings attended by HIF personnel; vendor visits; and reports prepared by HIF personnel.

Open-File Report↗
USGS2007

Comprehensive Areal Model of Earthquake-Induced Landslides: Technical Specification and User Guide

This report describes the complete design of a comprehensive areal model of earthquakeinduced landslides (CAMEL). This report presents the design process, technical specification of CAMEL. It also provides a guide to using the CAMEL source code and template ESRI ArcGIS map document file for applying CAMEL, both of which can be obtained by contacting the authors. CAMEL is a regional-scale model of earthquake-induced landslide hazard developed using fuzzy logic systems. CAMEL currently estimates areal landslide concentration (number of landslides per square kilometer) of six aggregated types of earthquake-induced landslides - three types each for rock and soil.

Open-File Report↗