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Click below for access to more than 170,000 publications written by USGS scientists over the century-plus history of the bureau.

Filter Total Items: 756

Nihoa and Laysan Island passerines population abundances, trends, and habitat utilization

Nihoa and Laysan Island, part of the Northwestern Hawaiian Islands, are host to three endangered passerine species—Nihoa finch (Telespiza ultima), Nihoa millerbird (Acrocephalus familiaris kingi), and Laysan finch (Telespiza cantans). Using point-transect distance sampling survey records from 2010 to 2022 for Nihoa and 2013 to 2019 for Laysan Island, we estimated the density and abundance of all t
Authors
Trevor Bak, Richard J. Camp, Chris Farmer, Rachel A. Rounds, Sheldon M. Plentovich, John Vetter, Paul C. Banko

Distribution of ancient carbon in groundwater and soil gas from degradation of petroleum near the Red Hill Bulk Fuel Storage Facility, O‘ahu, Hawai‘i

The groundwater below the Red Hill Bulk Fuel Storage Facility (the facility) in Oʻahu, Hawaiʻi, contains fuel compounds from past spills. This study used carbon-14 analyses to distinguish fuel-derived carbon from background carbon, along with other biodegradation indicators, to address two goals: (1) determine the extent and migration direction of groundwater affected by residual fuel below the fa

Authors
Jared J. Trost, Barbara A. Bekins, Jeanne B. Jaeschke, Geoffrey N. Delin, Daniel A Sinclair, James K Stack, Rylen K. Nakama, Uli'i M. Miyajima, Lhiberty D. Pagaduan, Isabelle M. Cozzarelli

Effects of drought and cloud-water interception on groundwater recharge and wildfire hazard for recent and future climate conditions, Kauaʻi, Oʻahu, Molokaʻi, Maui, and the Island of Hawaiʻi

The Water-budget Accounting for Tropical Regions Model (WATRMod) code was used for Kauaʻi, Oʻahu, Molokaʻi, Maui, and the Island of Hawaiʻi to estimate the spatial distribution of groundwater recharge, soil moisture, evapotranspiration, and climatic water deficit for a set of water-budget scenarios. The scenarios included historical and future drought conditions, and a land-cover condition where s
Authors
Alan Mair, Delwyn S. Oki, Heidi L. Kāne, Adam G. Johnson, Kolja Rotzoll

Estimated groundwater recharge for mid-century and end-of-century climate projections, Kaua‘i, O‘ahu, Moloka‘i, Lāna‘i, Maui, and the Island of Hawai‘i

Demand for freshwater in the State of Hawaiʻi is expected to increase by roughly 13 percent from 2020 to 2035. Groundwater availability in Hawaiʻi is affected by a number of factors, including land cover, rainfall, runoff, evapotranspiration, and climate change. To evaluate the availability of fresh groundwater under projected future-climate conditions, estimates of groundwater recharge are needed
Authors
Heidi L. Kāne, Alan Mair, Adam G. Johnson, Kolja Rotzoll, James Mifflin, Delwyn S. Oki

Post-Typhoon Mawar population counts of the endangered yǻyaguak (Mariana swiftlet) on Guam

The yǻyaguak (Mariana swiftlet, Aerodramus bartschi) is an endangered cave-roosting species native to Guam and southern Mariana Islands, Micronesia. The population on Guam has declined substantially over the last half century, likely due to the introduction of the brown treesnake (Boiga irregularis), but other factors have been proposed including habitat loss, pesticides, reduced food resources, a
Authors
Eben H. Paxton, P. Marcos Gorresen, Paul M. Cryan, Megan Parker

Groundwater and surface-water interactions in the He‘eia watershed, O‘ahu, Hawai‘i—Insights from analysis of historical data and numerical groundwater-model simulations

He‘eia and ‘Ioleka‘a Streams in the He‘eia watershed on O‘ahu, Hawai‘i, receive substantial discharge from dike-impounded groundwater. Previous studies indicated that groundwater withdrawals from the watershed affect streamflow. Resource managers and users seek information that can be used to balance the needs of competing uses of groundwater and streamflow in the watershed.In this study, analyses
Authors
Scot K. Izuka, Heidi L. Kāne, Kolja Rotzoll

Evaluation of data collected by Guam Division of Aquatic and Wildlife Resources during population establishment and monitoring of ko'ko' (Hypotaenidia owstoni) on Rota, Commonwealth of the Northern Mariana Islands, and wildlife monitoring datasets on Coco

Efforts to recover the critically endangered ko’ko’ (Guam rail, Hypotaenidia owstoni) through establishing an experimental population on the island of Rota in the Commonwealth of the Northern Mariana Islands have been ongoing for three decades. The U.S. Geological Survey collaborated with the Guam Division of Aquatic and Wildlife Resources and the Government of Guam to evaluate whether objectives
Authors
Richard J. Camp, Sarah A B Nash, Kristina L. Paxton

Establishment of terrestrial mammals on former reservoir beds following large dam removal on the Elwha River, Washington, USA

Terrestrial wildlife species are important yet often overlooked taxa in the recovery of ecosystems following dam removal. Their presence can shape ecosystem recovery, signal restoration of ecosystem function, and influence food web dynamics and nutrient transfer. We used camera traps to examine seasonal use of two former reservoir beds and an upstream reference reach by the mammalian community fol
Authors
Rebecca McCaffery, Sara Cendejas-Zarelli, Katy R Goodwin, Patricia J. Happe, Kurt Jenkins, Kimberly A. Sager-Fradkin

Invasive-dominated grasslands in Hawaiʻi are resilient to disturbance

Non-native-dominated landscapes may arise from invasion by competitive plant species, disturbance and invasion of early-colonizing species, or some combination of these. Without knowing site history, however, it is difficult to predict how native or non-native communities will reassemble after disturbance events. Given increasing disturbance levels across anthropogenically impacted landscapes, pre
Authors
Stephanie G. Yelenik, Eli T. Rose, Susan Cordell

Fine-resolution land cover mapping over large and mountainous areas for Lāna‘i, Hawaii using posterior probabilities, and expert knowledge

The task of accurately mapping species-specific vegetation cover in remote and topographically complex regions like those found in Hawaiʻi presents unique challenges. This study leverages a machine learning approach to accurately classify vegetation into fine species-specific classes across the island of Lāna‘i, Hawaii, offering a novel methodology for tackling such challenges. Utilizing high-reso
Authors
Lucas Fortini, Qiuming Cheng, Yoko Uyehara, Kari Bogner, Jonathan Sprague, Rachel Sprague

Adaptive resource management: Achieving functional eradication of invasive snakes to benefit avian conservation

Natural resource management often co-occurs with considerable uncertainty. One approach to mitigating uncertainty is through adaptive resource management (ARM), a specialized form of structured decision-making that modifies management decisions or actions through monitoring and implementation.Here, we present a case study on the attempted eradication of an invasive brown treesnake (Boiga irregular
Authors
Melia Gail Nafus, Amanda Reyes, Thomas Fies, Scott Michael Goetz

Videographic monitoring at caves to estimate population size of the endangered yǻyaguak (Mariana swiftlet) on Guam

The yǻyaguak (Mariana swiftlet; Aerodramus bartschi) is an endangered cave-nesting species historically found on Guam and the southern Mariana Islands, Micronesia. The population on Guam has been severely affected by the introduction of the brown treesnake Boiga irregularis. Population status assessments have, however, been challenging due to the limitations of traditional counting methods, which
Authors
P. Marcos Gorresen, Paul M. Cryan, Megan Parker, Frank Alig, Melia Gail Nafus, Eben H. Paxton