Articles
Science Quality and Integrity
The USGS provides unbiased, objective, and impartial scientific information upon which our audiences, including resource managers, planners, and other entities, rely.
The USGS provides unbiased, objective, and impartial scientific information upon which our audiences, including resource managers, planners, and other entities, rely.
Browse more than 65,000 articles authored by our scientists over the past 100+ year history of the USGS and refine search by topic, location, year, and advanced search.
Filter Total Items: 78946
Leveraging angler effort to inform fisheries management: Using harvest and harvest rate to estimate abundance of White Sturgeon Leveraging angler effort to inform fisheries management: Using harvest and harvest rate to estimate abundance of White Sturgeon
Traditional methods for estimating abundance of fish populations are not feasible in some systems due to complex population structure and constraints on sampling effort. Lincoln’s estimator provides a technique that uses harvest and harvest rate to estimate abundance. Using angler catch data allows assumptions of the estimator to be addressed without relying on methods that could be...
Authors
Marta Ulaski, Joshua McCormick, Michael C. Quist, Zachary Jackson
Evidence of a load-lightening helper effect in Florida Scrub-Jays: Implications for translocation Evidence of a load-lightening helper effect in Florida Scrub-Jays: Implications for translocation
The Florida Scrub-Jay (Aphelocoma coerulescens) is an imperiled cooperatively breeding species endemic to Florida scrub habitats. Translocation of non-reproductive helpers has been proposed as a conservation tool to increase population size and connectivity. However, the potential consequences of helper removal on the source population remain unclear because the benefits provided by...
Authors
Alexis Cardas, Erin Hewett Ragheb, Karl E. Miller, Abby Powell
The lunar cratering chronology The lunar cratering chronology
This chapter provides an introduction to crater-size frequency distribution (CSFD) measurements and presents a review of the work performed on dating lunar geological units using CSFDs since the last New Views of the Moon volume (2006), including various volcanic and tectonic features, as well as individual impact craters. At the end of the chapter, implications for the new CSFD age...
Authors
Harald Hiesinger, Carolyn H. Van der Bogert, G. Michael, N. Schmedemann, W. Iqbal, Stuart J. Robbins, B. Ivanov, Jean-Pierre Williams, M. Zanetti, J. Plescia, Lillian R. Ostrach, James W. Head III
Lunar mare basaltic volcanism: Volcanic features and emplacement processes Lunar mare basaltic volcanism: Volcanic features and emplacement processes
Volcanism is a fundamental process in the geological evolution of the Moon, providing clues to the composition and structure of the mantle, the location and duration of interior melting, the nature of convection and lunar thermal evolution. Progress in understanding volcanism has been remarkable in the short 60-year span of the Space Age. Before Sputnik 1 in 1957, the lunar farside was...
Authors
James W. Head III, Lionel Wilson, Harald Hiesinger, Carolyn H. Van der Bogert, Yuan Yuan Chen, James L. Dickson, Lisa Gaddis, Junichi Haruyama, Lauren Jozwiak, Erica Jawin, Chunlai Li, Jianzhong Liu, Tomokatsu Morota, Debra H. Needham, Lillian R. Ostrach, Carle M. Pieters, Tabb C. Prissel, Yuqi Qian, Lei Qiao, Malcolm R. Rutherford, David R. Scott, Jennifer L. Whitten, Long Xiao, Feng Zhang, Ouyang Ziyuan
Geographic distribution: Incilius alvarius (Sonoran desert toad) Geographic distribution: Incilius alvarius (Sonoran desert toad)
No abstract available.
Authors
Erika M. Nowak, Karina Cocks, Charles A. Drost, Janie Agyagos, Eve Berlinksy, Jennifer Steffen, Rafal Banas, Meredith Talbert, Sara Eno
Examining current bias and future projection consistency of globally downscaled climate projections commonly used in climate impact studies Examining current bias and future projection consistency of globally downscaled climate projections commonly used in climate impact studies
The associated uncertainties of future climate projections are one of the biggest obstacles to overcome in studies exploring the potential regional impacts of future climate shifts. In remote and climatically complex regions, the limited number of available downscaled projections may not provide an accurate representation of the underlying uncertainty in future climate or the possible...
Authors
Lucas Berio Fortini, Lauren R. Kaiser, Abby G. Frazier, Thomas W Giambelluca
Discovery of an active forearc fault in an urban region: Holocene rupture on the XEOLXELEK-Elk Lake fault, Victoria, British Columbia, Canada Discovery of an active forearc fault in an urban region: Holocene rupture on the XEOLXELEK-Elk Lake fault, Victoria, British Columbia, Canada
Subduction forearcs are subject to seismic hazard from upper plate faults that are often invisible to instrumental monitoring networks. Identifying active faults in forearcs therefore requires integration of geomorphic, geologic, and paleoseismic data. We demonstrate the utility of a combined approach in a densely populated region of Vancouver Island, Canada, by combining remote sensing
Authors
Nicolas Harrichhausen, Theron Finley, Kristin D. Morell, Christine Regalla, Scott E.K. Bennett, Lucinda J. Leonard, Edwin Nissen, Eleanor McLeod, Emerson M. Lynch, Guy Salomon, Israporn Sethanant
Simulation modeling to assess line transect distance sampling under a range of translocation scenarios Simulation modeling to assess line transect distance sampling under a range of translocation scenarios
The accuracy of posttranslocation population monitoring methods is critical to assessing long-term success in translocation programs. Translocation can produce unique challenges to monitoring efforts; therefore, it is important to understand the flexibility and robustness of commonly used monitoring methods. In Florida, USA, thousands of gopher tortoises Gopherus polyphemus have been...
Authors
Max D. Jones, Lora L. Smith, Katherine Gentry Richardson, J. Nicole DeSha, Traci Castellón, Dan Hipes, Alex Kalfin, Neal T. Halstead, Elizabeth Ann Hunter
Sonoran desert tortoise: Gopherus morafkai Sonoran desert tortoise: Gopherus morafkai
Sonoran Desert Tortoise Gopherus morafkai has most recently been assessed for The IUCN Red List of Threatened Species in 2019. Gopherus morafkai is listed as Vulnerable under criteria A2abce+4abce.
Authors
R.C. Averill-Murray, P.C. Rosen, C.A. Jones, T.R. Jones, R. A. Lara-Resendiz, Taylor Edwards, A. Karl, Kristin H. Berry
Modeling extreme water levels in the Salish Sea: The importance of including remote sea level anomalies for application in hydrodynamic simulations Modeling extreme water levels in the Salish Sea: The importance of including remote sea level anomalies for application in hydrodynamic simulations
Extreme water-level recurrence estimates for a complex estuary using a high-resolution 2D model and a new method for estimating remotely generated sea level anomalies (SLAs) at the model boundary have been developed. The hydrodynamic model accurately resolves the dominant physical processes contributing to extreme water levels across the Washington State waters of the Salish Sea...
Authors
Eric E. Grossman, Babak Tehranirad, Kees Nederhoff, Sean Crosby, Andrew W. Stevens, Nathan R. VanArendonk, Daniel J. Nowacki, Li H. Erikson, Patrick L. Barnard
A simple approach to modeling light attenuation in the Sacramento-San Joaquin Delta using commonly available data A simple approach to modeling light attenuation in the Sacramento-San Joaquin Delta using commonly available data
The diffuse attenuation coefficient of photosynthetically active radiation (KdPAR) is commonly used to predict light attenuation in aquatic productivity models, but obtaining measurements of PAR to compute KdPAR is difficult. In situ calculations of KdPAR require multiple measurements of PAR through the water column, and these measurements are infeasible for real-time recording. Instead
Authors
Emily T. Richardson, Keith Bouma-Gregson, Katy O’Donnell, Brian A. Bergamaschi
Comparison of δ13C analyses of individual foraminifer (Orbulina universa) shells by secondary ion mass spectrometry and gas source mass spectrometry Comparison of δ13C analyses of individual foraminifer (Orbulina universa) shells by secondary ion mass spectrometry and gas source mass spectrometry
Rationale: The use of secondary ion mass spectrometry (SIMS) to perform micrometer-scale in situ carbon isotope (δ13C) analyses of shells of marine microfossils called planktic foraminifers holds promise to explore calcification and ecological processes. The potential of this technique, however, cannot be realized without comparison to traditional whole-shell δ13C values measured by gas...
Authors
Jody Brae Wycech, Daniel Clay Kelly, Reinhard Kozdon, Akizumi Ishida, Kouki Kitajima, Howard J. Spero, John W. Valley