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Filter Total Items: 2,176
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Year Published: 2017

Variable effects of climate on forest growth in relation to climate extremes, disturbance, and forest dynamics

Changes in the frequency, duration, and severity of climate extremes are forecast to occur under global climate change. The impacts of climate extremes on forest productivity and health remain difficult to predict due to potential interactions with disturbance events and forest dynamics—changes in forest stand composition, density, size and age...

Itter, Malcolm S.; Finley, Andrew O.; D'Amato, Anthony W.; Foster, Jane R.; Bradford, John B.
Itter, M.S., Finley, A.O., D’Amato, A.W., Foster, J.R., and Bradford, J., 2017, Variable Effects of Climate on Forest Growth in Relation to Climate Extremes, Disturbance, and Forest Stand Dynamics, v. 27, no. 4, p. 1082-1095, http://dx.doi.org/10.1002/eap.1518.

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Year Published: 2017

A window of opportunity for climate-change adaptation: Easing tree mortality by reducing forest basal area

Increasing aridity as a result of climate change is expected to exacerbate tree mortality. Reducing forest basal area – the cross-sectional area of tree stems within a given ground area – can decrease tree competition, which may reduce drought-induced tree mortality. However, neither the magnitude of expected mortality increases, nor the potential...

Bradford, John B.; Bell, David M.
Bradford, J.B., and Bell, D.M., 2017, A window of opportunity for climate-change adaptation: easing tree mortality by reducing forest basal area: Frontiers in Ecology and the Environment, v. 15, p. 11-17, http://onlinelibrary.wiley.com/doi/10.1002/fee.1445/full.

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Year Published: 2017

Disturbance automated reference toolset (DART): Assessing patterns in ecological recovery from energy development on the Colorado Plateau

A new disturbance automated reference toolset (DART) was developed to monitor human land surface impacts using soil-type and ecological context. DART identifies reference areas with similar soils, topography, and geology; and compares the disturbance condition to the reference area condition using a quantile-based approach based on a satellite...

Nauman, Travis W.; Duniway, Michael C.; Villarreal, Miguel L.; Poitras, Travis B.
Nauman T.W., Duniway M.C., Villarreal M.L., Poitras T.B. Disturbance automated reference toolset (DART): Assessing patterns in ecological recovery from energy development on the Colorado Plateau Sci Total Environ. 2017 Apr 15;584-585:476-488.

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Year Published: 2017

The effects of drought and fire in the extirpation of an abundant semi-aquatic turtle from a lacustrine environment in the southwestern USA

We documented a significant mortality event affecting a southwestern pond turtle (Actinemys pallida) population living in a lake in southern California, USA. The area around the lake was impacted by a large wildland fire in 2013 that occurred during a protracted drought. As the mortality event was still unfolding, we collected data in 2014 on...

Lovich, Jeffrey E.; Quillman, Mari; Zitt, Brian; Schroeder, Adam; Green, David E.; Yackulic, Charles B.; Gibbons, Paul; Goode, Eric
Lovich, J.E., Quillman, M., Zitt, B., Schroeder, A., Green, D.E., Yackulic, C., Gibbons, P., and Goode, E., 2017, The effects of drought and fire in the extirpation of an abundant semi-aquatic turtle from a lacustrine environment in the southwestern USA: Knowledge & Management of Aquatic Ecosystems, v. 418, no. 18, http://www.kmae-journal.org/articles/kmae/pdf/2017/01/kmae160179.pdf.

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Year Published: 2017

Benefits of the destinations, not costs of the journeys, shape partial migration patterns

1. The reasons that lead some animals to seasonally migrate, and others to remain in the same area year-round, are poorly understood. Associations between traits, such as body size, and migration provide clues. For example, larger species and individuals are more likely to migrate.2. One explanation for this size bias in migration is that larger...

Yackulic, Charles B.; Blake, Stephen; Bastille-Rousseau, Guillaume
Yackulic, C.B., Blake, S., and Bastille-Rousseau, G., 2017, Benefits of the destinations, not costs of the journeys, shape partial migration patterns: Journal of Animal Ecology, online, DOI: 10.1111/1365-2656.12679.

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Year Published: 2017

Geomorphic process from topographic form: automating the interpretation of repeat survey data in river valleys

The ability to quantify the processes driving geomorphic change in river valley margins is vital to geomorphologists seeking to understand the relative role of transport mechanisms (e.g. fluvial, aeolian, and hillslope processes) in landscape dynamics. High-resolution, repeat topographic data are becoming readily available to geomorphologists. By...

Kasprak, Alan; Caster, Joshua J.; Bangen, Sara G.; Sankey, Joel B.
Kasprak, A., Caster, J., Bangen, S.G., and Sankey, J.B., 2017, Geomorphic process from topographic form:automating the interpretation of repeat survey data in river valleys: Earth Surface Processes and Landforms, online, DOI: 10.1002/esp.4143

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Year Published: 2017

Terrestrial subaqueous seafloor dunes: Possible analogs for Venus

Dunes on Venus, first discovered with Magellan Synthetic Aperture Radar (SAR) in the early 1990s, have fueled discussions about the viability of Venusian dunes and aeolian grain transport. Confined to two locations on Venus, the existence of the interpreted dunes provides evidence that there could be transportable material being mobilized into...

Neakrase, Lynn D.V.; Klose, Martina; Titus, Timothy N.

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Year Published: 2017

Density-dependent vulnerability of forest ecosystems to drought

1. Climate models predict increasing drought intensity and frequency for many regions, which may have negative consequences for tree recruitment, growth and mortality, as well as forest ecosystem services. Furthermore, practical strategies for minimizing vulnerability to drought are limited. Tree population density, a metric of tree abundance in a...

Bottero, Alessandra; D'Amato, Anthony W.; Palik, Brian J.; Bradford, John B.; Fraver, Shawn; Battaglia, Mike A.; Asherin, Lance A.
Bottero, A., D’Amato, A.W., Palik, B.J., Bradford, J.B., Fraver, S., Battaglia, M.A., and Asherin, L.A., 2017, Density-dependent vulnerability of forest ecosystems to drought, Journal of Applied Ecology, v. (online), http://onlinelibrary.wiley.com/doi/10.1111/1365-2664.12847/full and http://dx.doi.org/10.1111/1365-2664.12847.

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Year Published: 2017

Channel mapping river miles 29–62 of the Colorado River in Grand Canyon National Park, Arizona, May 2009

Bathymetric, topographic, and grain-size data were collected in May 2009 along a 33-mi reach of the Colorado River in Grand Canyon National Park, Arizona. The study reach is located from river miles 29 to 62 at the confluence of the Colorado and Little Colorado Rivers. Channel bathymetry was mapped using multibeam and singlebeam echosounders,...

Kaplinski, Matt; Hazel, Joseph E.; Grams, Paul E.; Kohl, Keith; Buscombe, Daniel D.; Tusso, Robert B.
Kaplinski, M., Hazel, J.E., Jr., Grams, P.E., Kohl, Keith, Buscombe, D.D., and Tusso, R.B., 2017, Channel mapping river miles 29–62 of the Colorado River in Grand Canyon National Park, Arizona, May 2009: U.S. Geological Survey Open-File Report 2017–1030, 35 p., https://doi.org/10.3133/ofr20171030.

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Year Published: 2017

Changes in community-level riparian plant traits over inundation gradients, Colorado River, Grand Canyon

Comparisons of community-level functional traits across environmental gradients have potential for identifying links among plant characteristics, adaptations to stress and disturbance, and community assembly. We investigated community-level variation in specific leaf area (SLA), plant mature height, seed mass, stem specific gravity (SSG), relative...

McCoy-Sulentic, Miles; Kolb, Thomas; Merritt, David; Palmquist, Emily C.; Ralston, Barbara E.; Sarr, Daniel; Shafroth, Patrick B.
McCoy-Sulentic, M.E., Kolb, T.E., Merritt, D.M., Palmquist, E., Ralston, B.E., Sarr, D.A., and Shafroth, P.B., 2017, Changes in Community-Level Riparian Plant Traits over Inundation Gradients, Colorado River, Grand Canyon: Wetlands, online, doi:10.1007/s13157-017-0895-3.

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Year Published: 2017

The vanishing cryovolcanoes of Ceres

Ahuna Mons is a 4 km tall mountain on Ceres interpreted as a geologically young cryovolcanic dome. Other possible cryovolcanic features are more ambiguous, implying that cryovolcanism is only a recent phenomenon or that other cryovolcanic structures have been modified beyond easy identification. We test the hypothesis that Cerean cryovolcanic...

Sori, Michael M.; Byrne, Shane; Bland, Michael T.; Bramson, Ali; Ermakov, Anton; Hamilton, Christoper; Otto, Katharina; Ruesch, Ottaviano; Russell, Christopher

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Year Published: 2017

Functional traits and ecological affinities of riparian plants along the Colorado River in Grand Canyon

Trait-based approaches to vegetation analyses are becoming more prevalent in studies of riparian vegetation dynamics, including responses to flow regulation, groundwater pumping, and climate change. These analyses require species trait data compiled from the literature and floras or original field measurements. Gathering such data makes trait-...

Palmquist, Emily C.; Ralston, Barbara E.; Sarr. Daniel; Merritt, David; Shafroth, Patrick B; Scott, Julian
Palmquist, E.C., Ralston, B.R., Sarr, D., Merritt D.M., Shafroth, P.B., and Scott, J.A., 2017, Functional traits and ecological affinities of riparian plants along the Colorado River in Grand Canyon: Western North American Naturalist, v. 77, no. 1, p. 22--30, http://scholarsarchive.byu.edu/wnan/vol77/iss1/3.

Filter Total Items: 239
Image: Killdeer
May 10, 2006

Killdeer

Birds found in and around the Salton Sea, California.

Attribution: Southwest
Image: Cattle Egret
May 5, 2006

Cattle Egret

Birds found in and around the Salton Sea, California.

Attribution: Southwest
Image: Black Bellied Plover
May 5, 2006

Black Bellied Plover

Birds found in and around the Salton Sea, California.

Attribution: Southwest
Andrew Schwartz and Dan Hanes hold a current profiler for a study of surf-zone hydrodynamics at Ocean Beach, San Francisco.
January 30, 2006

Studying Surf-Zone Hydrodynamics

USGS scientists Andrew Schwartz and Dan Hanes maneuver a current profiler for a study of surf-zone hydrodynamics at Ocean Beach, on the west side of San Francisco, California. Beach erosion has been a continuing problem in this area. This fieldwork is part of an effort to document, analyze, and simulate the processes that control sand transport and sedimentation patterns

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A home, severely damaged by the tsunami that hit Sumatra on December 26, 2004, sits atop debris.
January 21, 2005

Heavily damaged home in Banda Aceh, Sumatra from the 2004 tsunami

A severely damaged home, or a portion of one, sits atop debris in Banda Aceh on the island of Sumatra. Damage was caused by a massive, highly destructive tsunami, triggered by a magnitude 9.1 earthquake just offshore of Sumatra, on December 26, 2004.

Moutain Diablo in the early morning
December 31, 2004

Mt. Diablo from Suisun Marsh

Picturesque view of Mt.Diablo early in the morning from Suisun Marsh.

Attribution: Southwest
Water quality sampling using a Niskin sampler from the Research Vessel Polaris at sunset on San Francisco Bay.
December 31, 2003

Water quality sampling on San Francisco Bay

USGS conducts water quality sampling to describe changes in water quality along the deep channel of the San Francisco Bay-Delta system. Sampling includes continuious sampling and discrete sampling. Here a water discrete water sample is collected using a Niskin sampler at sunset in north San Francisco Bay.

Evaportranspiration equipment along the Tracy Segment, Nevada
April 30, 2003

Evaportranspiration equipment along the Tracey Segment

Evaportranspiration equipment along the Tracey Segment

USGS regional research drill rig near Truckee River, NV
June 9, 2001

USGS regional research drill rig near Truckee River, NV

USGS regional research drill rig constructing sites near the south bank of the Truckee River just downstream of USGS 10350000 Truckee River at Vista. The wells were constructed to investigate surface water groundwater interaction.

Irrigation ditch alongside an agricultural field.
December 31, 2000

Irrigation ditch alongside an agricultural field in California's Central Valley

Irrigation systems in Central California Valley Ecoregion: Single-field irrigation ditch.

Attribution: Southwest
Grasslands and agricultural fields in the flat foreground, with housing development on the hills beyond.
December 31, 2000

Grasslands and agricultural fields, with housing development on the hills beyond.

Conversions of grassland/shrubland and agriculture to developed land were two common land-cover changes in Southern and Central California Chaparral and Oak Woodlands Ecoregion.

Attribution: Southwest

Nine USGS Science Centers are administered by the Pacific Regional office, which is headquartered in Sacramento, California.