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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.

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Statistical methods used in research concerning endangered and threatened animal species of Puerto Rico: A meta-study Statistical methods used in research concerning endangered and threatened animal species of Puerto Rico: A meta-study

A concern about statistics in wildlife studies, particularly of endangered and threatened species, is whether the data collected meet the assumptions necessary for the use of parametric statistics. This study identified published papers on the nine endangered and six threatened species found only on Puerto Rico using five different databases. The results from the Zoological Record...
Authors
S.J. Rivera, K.M. Alpi, Jaime A. Collazo, M.K. Stoskopf

Distribution of tiger salamanders in northern Sonora, Mexico: Comparison of sampling methods and possible implications for an endangered subspecies Distribution of tiger salamanders in northern Sonora, Mexico: Comparison of sampling methods and possible implications for an endangered subspecies

Many aquatic species in the arid USA-Mexico borderlands region are imperiled, but limited information on distributions and threats often hinders management. To provide information on the distribution of the Western Tiger Salamander (Ambystoma mavortium), including the USA-federally endangered Sonoran Tiger Salamander (Ambystoma mavortium stebbinsi), we used traditional (seines, dip-nets)...
Authors
Blake R. Hossack, Julio A. Lemos-Espinal, Brent H. Sigafus, Erin L. Muths, Gerardo Carreon Arroyo, Daniel Toyos Martinez, David Hurtado Felix, Guillermo Molina Padilla, Caren S. Goldberg, T. R. Jones, M. J. Sredl, Thierry Chambert, J. C. Rorabaugh

Factors influencing distribution of Coccidioides immitis in soil, Washington State, 2016 Factors influencing distribution of Coccidioides immitis in soil, Washington State, 2016

Coccidioides immitis and Coccidioides posadasii are causative agents of Valley fever, a serious fungal disease endemic to regions with hot, arid climate in the United States, Mexico, and Central and South America. The environmental niche of Coccidioides spp. is not well defined, and it remains unknown whether these fungi are primarily associated with rodents or grow as saprotrophs in...
Authors
Nancy A. Chow, David Kangiser, Lalitha Gade, Orion Z. McCotter, Steven Hurst, Amy Salamone, Ron Wohrle, Wayne Clifford, Sunkyung Kim, Zainab Salah, Hanna N. Oltean, Geoffrey S. Plumlee, Anastasia P. Litvintseva

Seven decades of coastal change at Barter Island, Alaska: Exploring the importance of waves and temperature on erosion of coastal permafrost bluffs Seven decades of coastal change at Barter Island, Alaska: Exploring the importance of waves and temperature on erosion of coastal permafrost bluffs

Observational data of coastal change over much of the Arctic are limited largely due to its immensity, remoteness, harsh environment, and restricted periods of sunlight and ice-free conditions. Barter Island, Alaska, is one of the few locations where an extensive, observational dataset exists, which enables a detailed assessment of the trends and patterns of coastal change over decadal...
Authors
Ann E. Gibbs, Li H. Erikson, Benjamin M. Jones, Bruce M. Richmond, Anita C Engelstad

A simple low-cost approach for transport parameter determination in mountain rivers A simple low-cost approach for transport parameter determination in mountain rivers

A simplified low-cost approach to experimentally determine transport parameters in mountain rivers is described, with an emphasis on the longitudinal dispersion coefficient (DL). The approach is based on a slug injection of table salt (NaCl) as a tracer and specific conductance readings at different locations downstream of the injection spot. Observed specific conductance readings are...
Authors
Daniella Castillo, Robert L. Runkel, Denisse Duhalde, Pablo Pasten, José L. Arumí, Jorge Oyarzun, Jorge Núñez, Hugo Maturana, Ricardo Oyarzun

Comment on “Which earthquake accounts matter” by Susan E. Hough and Stacey S. Martin Comment on “Which earthquake accounts matter” by Susan E. Hough and Stacey S. Martin

In their analysis of the U.S. Geological Survey’s (USGS) “Did You Feel It?” (DYFI) data Hough and Martin (2021) claim, among other assertions, that the following: Socioeconomic and geopolitical factors can introduce biases in the USGS’ characterization of earthquakes and their effects, especially if online data collection systems are not designed to be broadly accessible; These biases...
Authors
David J. Wald

Estimating abundance, temporary emigration and the pattern of density dependence in a cyclic snowshoe hare population in Yukon, Canada Estimating abundance, temporary emigration and the pattern of density dependence in a cyclic snowshoe hare population in Yukon, Canada

Estimates of demographic parameters based on capture-mark-recapture (CMR) methods may be biased when some individuals in the population are temporarily unavailable for capture (temporary emigration). We estimated snowshoe hare abundance, apparent survival, and probability of temporary emigration in a population of snowshoe hares (Lepus americanus Erxleben 1777) in the Yukon using Pollock...
Authors
Madan K. Oli, Alice J Kenny, Rudy Boonstra, Stan Boutin, Vratika Chaudhary, James E. Hines, Charles J Krebs

Loop-mediated isothermal amplification (LAMP) assay for detection of Asian fish tapeworm, Schyzocotyle acheilognathi (Yamaguti, 1934) [syn. Bothriocephalus acheilognathi] Loop-mediated isothermal amplification (LAMP) assay for detection of Asian fish tapeworm, Schyzocotyle acheilognathi (Yamaguti, 1934) [syn. Bothriocephalus acheilognathi]

The Asian fish tapeworm (Schyzocotyle acheilognathi syn. Bothriocephalus acheilognathi) (AFT) is an invasive parasite that can infect many species of fish, although most hosts are primarily members of Cyprinidae. Pathogenicity has most often been reported in aquaculture settings in fry and fingerling stages of carp (Cyprinus spp.). More recently, it has been shown to cause growth...
Authors
Erik K. Hofmeister, Fiona Antigoni Georgousi, Melissa Lund, Constance Roderick, Anindo Choudhury, Gary Whelan, Rebecca A. Cole

Expanding freshwater biologger studies to view fish as environmental sensing platforms Expanding freshwater biologger studies to view fish as environmental sensing platforms

While recording fish habitat use by electronic sensors, biologgers can also be viewed as autonomous environmental monitoring systems with the organism as a vehicle. This dual perspective has provided novel results from marine ecosystems, but has not been applied to freshwater ecosystems. To understand limitations in fresh water, we evaluated miniature depth and temperature recorders as...
Authors
Richard Kraus, Helen Bontrager, Chris Vandergoot, Matthew Faust

A basin-scale approach to estimating recharge in the desert: Anza-Cahuilla groundwater basin, CA A basin-scale approach to estimating recharge in the desert: Anza-Cahuilla groundwater basin, CA

The Anza-Cahuilla groundwater basin located mainly in the semi-arid headwaters of the Santa Margarita River watershed in southern California is the principle source of groundwater for a rural disadvantaged community and two Native American Tribes, the Ramona Band of Cahuilla and the Cahuilla. Groundwater in the study area is derived entirely from precipitation and managing groundwater...
Authors
Michelle A. Stern, Lorraine E. Flint, Alan L. Flint, Allen H. Christensen

Modeling marsh dynamics using a 3-D coupled wave-flow-sediment model Modeling marsh dynamics using a 3-D coupled wave-flow-sediment model

Salt marshes are dynamic biogeomorphic systems that respond to external physical factors, including tides, sediment transport, and waves, as well as internal processes such as autochthonous soil formation. Predicting the fate of marshes requires a modeling framework that accounts for these processes in a coupled fashion. In this study, we implement two new marsh dynamic processes in the...
Authors
Tarandeep S. Kalra, Neil K. Ganju, Alfredo Aretxabaleta, Joel A. Carr, Zafer Defne, Julia Moriarty

Long-term Mississippi River trends expose shifts in the river load response to watershed nutrient balances between 1975 and 2017 Long-term Mississippi River trends expose shifts in the river load response to watershed nutrient balances between 1975 and 2017

Excess nutrients transported by the Mississippi River (MR) contribute to hypoxia in the Gulf of Mexico. Nutrient balances are key drivers to river nutrient loads and represent inputs (fertilizer, manure, deposition, wastewater, N-fixation, and weathering) minus outputs (nutrient uptake and removal in harvest, and N emissions). Here, we quantified annual changes in nitrogen (N) and...
Authors
Sarah M. Stackpoole, Robert D. Sabo, James A. Falcone, Lori A. Sprague
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