Skip to main content
U.S. flag

An official website of the United States government

Articles

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: 77855

Patterns of post-fire invasion of semiarid shrub-steppe reveals a diversity of invasion niches within an exotic annual grass community Patterns of post-fire invasion of semiarid shrub-steppe reveals a diversity of invasion niches within an exotic annual grass community

Disturbances such as fire provide an opportunity for invasive plant species to exploit newly created niche space. Whether initial invaders facilitate, compete with, or do not affect later invaders is important to determine in communities affected by multiple invaders. This analysis focuses on the newer invaders Taeniatherum caput-medusae (medusahead) and Ventenata dubia (ventenata) in...
Authors
Cara Applestein, Matthew J. Germino

Loggerhead marine turtles (Caretta caretta) nesting at smaller sizes than expected in the Gulf of Mexico: Implications for turtle behavior, population dynamics, and conservation Loggerhead marine turtles (Caretta caretta) nesting at smaller sizes than expected in the Gulf of Mexico: Implications for turtle behavior, population dynamics, and conservation

Estimates of parameters that affect population dynamics, including the size at which individuals reproduce, are crucial for efforts aimed at understanding how imperiled species may recover from the numerous threats they face. In this study, we observed loggerhead marine turtles (Caretta caretta) nesting at three sites in the Gulf of Mexico at sizes assumed nonreproductive in this region...
Authors
Allison Benscoter, Brian J. Smith, Kristen Hart

Warming sea surface temperatures fuel summer epidemics of eelgrass wasting disease Warming sea surface temperatures fuel summer epidemics of eelgrass wasting disease

Seawater temperatures are increasing, with many unquantified impacts on marine diseases. While prolonged temperature stress can accelerate host-pathogen interactions, the outcomes in nature are poorly quantified. We monitored eelgrass wasting disease (EWD) from 2013-2017 and correlated mid-summer prevalence of EWD with remotely sensed seawater temperature metrics before, during, and...
Authors
Maya Groner, Morgan E. Eisenlord, Reyn M. Yoshioka, Evan A. Fiorenza, Phoebe D. Dawkins, Olivia J. Graham, Miranda Winningham, Alex Vompe, Natalie D. Rivlin, Bo Yang, Colleen A. Burge, Brendan Rappazzo, Carla P. Gomes, C. Drew Harvell

The aboveground and belowground growth characteristics of juvenile conifers in the southwestern United States The aboveground and belowground growth characteristics of juvenile conifers in the southwestern United States

Juvenile tree survival will play an important role in the persistence of coniferous forests and woodlands in the southwestern United States (SWUS). Vulnerability to climatic and environmental stress declines as trees grow, such that larger, more deeply rooted juveniles are less likely to experience mortality. It is unclear how juvenile conifers partition the aboveground and belowground...
Authors
N.L. Pirtel, R.M. Hubbard, John B. Bradford, T.E. Kolb, M.E. Litvak, S.R. Abella, S.M. Porter, Petrie M.D.

Calcareous plankton biostratigraphic fidelity and species richness during the last 10 m.y. of the Cretaceous at Blake Plateau, subtropical North Atlantic Calcareous plankton biostratigraphic fidelity and species richness during the last 10 m.y. of the Cretaceous at Blake Plateau, subtropical North Atlantic

Species distributions of well-preserved and diverse assemblages of planktonic foraminifera and calcareous nannofossils spanning the last 10 m.y. of the Cretaceous (middle Campanian through Maastrichtian) are analyzed from samples taken across a 1400 m depth transect at Blake Nose in the western subtropical North Atlantic (Ocean Drilling Program Sites 1049, 1050 and 1052). Age models...
Authors
Brian T. Huber, Nataliya A. Tur, Jean Self-Trail, Kenneth G. MacLeod

Assessing the migratory histories, trophic positions, and conditions of lake sturgeon in the St. Croix and Mississippi Rivers using fin ray microchemistry, stable isotopes, and fatty acid profiles Assessing the migratory histories, trophic positions, and conditions of lake sturgeon in the St. Croix and Mississippi Rivers using fin ray microchemistry, stable isotopes, and fatty acid profiles

Background Reproducing populations of invasive carps (Hypophthalmichthys spp.) could alter aquatic food webs and negatively affect native fishes in the Mississippi National River and Recreation Area (MISS) and the St. Croix National Scenic Riverway (SACN). However, proposed invasive carp barriers may also threaten populations of native migratory fishes by preventing movements of fish...
Authors
Jeffrey R. Ziegeweid, Michelle Bartsch, Lynn A. Bartsch, Steven J. Zigler, Robert J Kennedy, Seth A. Love

Long-term Pseudogymnoascus destructans surveillance data reveal factors contributing to pathogen presence Long-term Pseudogymnoascus destructans surveillance data reveal factors contributing to pathogen presence

The disease white-nose syndrome (WNS) was first recognized in upstate New York in 2006 and has since spread across much of the United States (U.S.), causing severe mortality in several North American bat species. To aid in the identification and monitoring of at-risk bat populations, we evaluate factors associated with the presence of the causative fungal agent of WNS, Pseudogymnoascus...
Authors
John Grider, Robin E. Russell, Anne Ballmann, Trevor J. Hefley

The Yorktown Formation: Improved stratigraphy, chronology and paleoclimate interpretations from the U.S. mid-Atlantic Coastal Plain The Yorktown Formation: Improved stratigraphy, chronology and paleoclimate interpretations from the U.S. mid-Atlantic Coastal Plain

The Yorktown Formation records paleoclimate conditions along the mid-Atlantic Coastal Plain during the mid-Piacenzian Warm Period (3.264 to 3.025 Ma), a climate interval of the Pliocene in some ways analogous to near future climate projections. To gain insight into potential near future changes, we investigated Yorktown Formation outcrops and cores in southeastern Virginia, refining the
Authors
Harry J. Dowsett, Marci M. Robinson, Kevin M. Foley, Timothy D. Herbert

Anomalous noble gas solubility in liquid cloud water: Possible implications for noble gas temperatures and cloud physics Anomalous noble gas solubility in liquid cloud water: Possible implications for noble gas temperatures and cloud physics

The noble gas temperature climate proxy is an established tool that has previously been applied to determine the source of groundwater recharge, however, unanswered questions remain. In fractured media (e.g., volcanic islands) recharge can be so rapid that groundwater is significantly depleted in heavy noble gases, indicating that the water has retained noble gas concentrations from...
Authors
Chris M. Hall, M. Clara Castro, Martha A. Scholl, Julien Amalberti, Stephen B. Gingerich

Hierarchical models improve the use of alligator abundance as an indicator Hierarchical models improve the use of alligator abundance as an indicator

Indicator species are species which can be monitored as an index to measure the overall health of an ecosystem. Crocodylians have been shown to be good indicators of wetland condition as they respond to changes in hydrology, can be efficiently monitored, and are a key part of ecosystem trophic relationships. Eye shine surveys at night are a standard method used to sample alligators, but...
Authors
Seth C. Farris, J. Hardin Waddle, Caitlin E. Hackett, Laura A. Brandt, Frank J. Mazzotti

Impacts of extreme environmental disturbances on piping plover survival are partially moderated by migratory connectivity Impacts of extreme environmental disturbances on piping plover survival are partially moderated by migratory connectivity

Effective conservation for listed migratory species requires an understanding of how drivers of population decline vary spatially and temporally, as well as knowledge of range-wide connectivity between breeding and nonbreeding areas. Environmental conditions distant from breeding areas can have lasting effects on the demography of migratory species, yet these consequences are often the...
Authors
Kristen S. Ellis, Michael J. Anteau, Francesca J. Cuthbert, Cheri L Gratto-Trevor, Joel G. Jorgensen, David J Newstead, Larkin A. Powell, Megan M. Ring, Mark H. Sherfy, Rose J. Swift, Dustin L. Toy, David N. Koons

Factors Affecting Groundwater Quality Used for Domestic Supply in Marcellus Shale Region of North-Central and North-East Pennsylvania, USA Factors Affecting Groundwater Quality Used for Domestic Supply in Marcellus Shale Region of North-Central and North-East Pennsylvania, USA

Factors affecting groundwater quality used for domestic supply within the Marcellus Shale footprint in north-central and north-east Pennsylvania are identified using a combination of spatial, statistical, and geochemical modeling. Untreated groundwater, sampled during 2011–2017 from 472 domestic wells within the study area, exhibited wide ranges in pH (4.5–9.3), total dissolved solids...
Authors
Charles A. Cravotta, Lisa A. Senior, Matthew D. Conlon
Was this page helpful?