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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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Gopherus polyphemus (Gopher Tortoise) adult mortality Gopherus polyphemus (Gopher Tortoise) adult mortality

Gopherus polyphemus has typically high adult survivorship, with some populations reaching a mean annual survivorship of 93.4% (Howell et al. 2019. J. Wildl. Manage. 84:56–65). Instances of adult mortality are not commonly reported outside of large mortality events, and most often result from disease, starvation, dehydration, or chronic stress (Gates et al. 2002. Florida Sci. 65:185– 197...
Authors
Michael Palandri, Margaret M. Lamont

Hydrological control shift from river level to rainfall in the reactivated Guobu slope besides the Laxiwa hydropower station in China Hydrological control shift from river level to rainfall in the reactivated Guobu slope besides the Laxiwa hydropower station in China

Landslides are common geohazards associated with natural drivers such as precipitation, land degradation, toe erosion by rivers and wave attack, and ground shaking. On the other hand, human alterations such as inundation by water impoundment or rapid drawdown may also destabilize the surrounding slopes. The Guobu slope is an ancient rockslide on the banks of the Laxiwa hydropower station...
Authors
Xuguo Shi, Xie Hu, Nicholas Sitar, Robert Kayen, Shengwen Qi, Houjun Jiang, Xudong Wang

Spatial and temporal dynamics of phytoplankton assemblages in the upper Mississippi River Spatial and temporal dynamics of phytoplankton assemblages in the upper Mississippi River

Phytoplankton provide large quantities of organic carbon and biomolecules that support large river ecosystems. However, when certain groups become overabundant (e.g., cyanobacteria), they can pose a risk to human health and river biota. The purpose of this study was to examine the spatial and temporal dynamics of phytoplankton community composition within the upper Mississippi River...
Authors
John T. Manier, Roger J. Haro, Jeffrey N. Houser, Eric A. Strauss

Experimental warming and its legacy effects on root dynamics following two hurricane disturbances in a wet tropical forest Experimental warming and its legacy effects on root dynamics following two hurricane disturbances in a wet tropical forest

Tropical forests are expected to experience unprecedented warming and increases in hurricane disturbances in the coming decades; yet, our understanding of how these productive systems, especially their belowground component, will respond to the combined effects of varied environmental changes remains empirically limited. Here we evaluated the responses of root dynamics (production...
Authors
Daniela Yaffar, Tana E. Wood, Sasha C. Reed, Benjamin L. Branoff, Molly A. Cavaleri, Richard J. Norby

Bayesian change point quantile regression approach to enhance the understanding of shifting phytoplankton-dimethyl sulfide relationships in aquatic ecosystems Bayesian change point quantile regression approach to enhance the understanding of shifting phytoplankton-dimethyl sulfide relationships in aquatic ecosystems

Dimethyl sulfide (DMS) serves as an anti-greenhouse gas, plays multiple roles 7 in aquatic ecosystems, and contributes to the global sulfur cycle. The chlorophyll 8 a (CHL, an indicator of phytoplankton biomass)-DMS relationship is critical for 9 estimating DMS emissions from aquatic ecosystems. Importantly, recent research has 10 identified that the CHL-DMS relationship has a breakpoint
Authors
Zhongyao Liang, Yong Liu, Yaoyang Xu, Tyler Wagner

Semi-centennial of Landsat observations and pending Landsat 9 launch Semi-centennial of Landsat observations and pending Landsat 9 launch

The first Landsat was placed in orbit on 23 July 1972, followed by a series of missions that have provided nearly continuous, two-satellite 8-day repeat image coverage of the Earth’s land areas for the last half-century. These observations have substantially enhanced our understanding of the Earth’s terrestrial dynamics, both as a major element of the Earth’s physical system, the primary...
Authors
Samuel N. Goward, Jeffery G. Masek, Thomas Loveland, John L. Dwyer, Darrel L. Williams, Terry Arvidson, Laura E.P. Rocchio, James R. Irons

Diffuse deformation and surface faulting distribution from sub-metric image correlation along the 2019 Ridgecrest ruptures (California, USA) Diffuse deformation and surface faulting distribution from sub-metric image correlation along the 2019 Ridgecrest ruptures (California, USA)

The 2019 Mw 6.4 and 7.1 Ridgecrest, California, earthquake sequence (July 2019) ruptured consecutively a system of high‐angle strike‐slip cross faults (northeast‐ and northwest‐trending) within 34 hr. The complex rupture mechanism was illuminated by seismological and geodetic data, bringing forward the issue of the interdependency of the two fault systems both at depth and at the surface...
Authors
Solene L. Antoine, Yann Klinger, Arthur Delorme, Kang Wang, Roland Burgmann, Ryan D. Gold

Hydrologic and geomorphic effects on riparian plant species occurrence and encroachment: Remote sensing of 360 km of the Colorado River in Grand Canyon Hydrologic and geomorphic effects on riparian plant species occurrence and encroachment: Remote sensing of 360 km of the Colorado River in Grand Canyon

A common impact on riparian ecosystem function following river regulation is the expansion and encroachment of riparian plant species in the active river channels and floodplain, which reduces flow of water and suspended sediment between the river, riparian area, and upland ecosystems. We characterized riparian plant species occurrence and quantified encroachment within the dam-regulated...
Authors
Laura E. Durning, Joel B. Sankey, Charles B. Yackulic, Paul E. Grams, Bradley J. Butterfield, Temuulen T. Sankey

Demography of the Appalachian Spotted Skunk (Spilogale putorius putorius) Demography of the Appalachian Spotted Skunk (Spilogale putorius putorius)

Spilogale putorius (Eastern Spotted Skunk) is a small, secretive carnivore that has substantially declined throughout the eastern United States since the mid-1900s. To better understand the current status of Eastern Spotted Skunks, we studied survival and reproduction of the S. p. putorius (Appalachian Spotted Skunk) subspecies across 4 states in the central and southern Appalachian...
Authors
Andrew R. Butler, Andrew J. Edelman, Robin Y. Y. Eng, Stephen N. Harris, Colleen Olfenbuttel, Emily D. Thorne, W. Mark Ford, David S. Jachowski

An updated assessment of status and trend in the distribution of the Cascades frog (Rana cascadae) in Oregon, USA An updated assessment of status and trend in the distribution of the Cascades frog (Rana cascadae) in Oregon, USA

Conservation efforts need reliable information concerning the status of a species and their trends to help identify which species are in most need of assistance. We completed a comparative evaluation of the occurrence of breeding for Cascades Frog (Rana cascadae), an amphibian that is being considered for federal protection under the U.S. Endangered Species Act. Specifically, in 2018...
Authors
Adam Duarte, Christopher Pearl, Brome McCreary, Jennifer Rowe, Michael J. Adams

Probabilistic fault displacement hazard assessment (PFDHA) for nuclear installations according to IAEA safety standards Probabilistic fault displacement hazard assessment (PFDHA) for nuclear installations according to IAEA safety standards

In the last 10 yr, the International Atomic Energy Agency (IAEA) revised its safety standards for site evaluations of nuclear installations in response to emerging fault displacement hazard evaluation practices developed in Member States. New amendments in the revised safety guidance (DS507) explicitly recommend fault displacement hazard assessment, including separate approaches for...
Authors
Alessandro Valentini, Yoshimitsu Fukushima, Paolo Contri, Masato Ono, Toshiaki Sakai, Stephen Thompson, Emmanuel Viallet, Tadashi Annaka, Rui Chen, Robb E. S. Moss, Mark D. Petersen, Francesco Visini, Robert Youngs

Acoustic interaction between a pair of owls and a wolf Acoustic interaction between a pair of owls and a wolf

During summer 2019, we recorded an apparent vocal interaction, lasting just under 4 min, between a pair of Great Horned Owls (Bubo virginianus) and a gray wolf (Canis lupus) in Yellowstone National Park. To our knowledge, this is the first report of such an acoustic interaction in the scientific literature. The increased use of passive acoustic recorders, which record spontaneous...
Authors
Barbara Marti-Domken, Vicente Palacios, Shannon Barber-Meyer
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