Publications
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Comparing ecoregional classifications for natural areas management in the Klamath Region, USA Comparing ecoregional classifications for natural areas management in the Klamath Region, USA
We compared three existing ecoregional classification schemes (Bailey, Omernik, and World Wildlife Fund) with two derived schemes (Omernik Revised and Climate Zones) to explore their effectiveness in explaining species distributions and to better understand natural resource geography in the Klamath Region, USA. We analyzed presence/absence data derived from digital distribution maps for...
Authors
Daniel A. Sarr, Andrew Duff, Eric C. Dinger, Sarah L. Shafer, Michael Wing, Nathaniel E. Seavy, John D. Alexander
Paleodischarge of the Mojave River, southwestern U.S.A, investigated with single-pebble measurements of 10Be Paleodischarge of the Mojave River, southwestern U.S.A, investigated with single-pebble measurements of 10Be
The paleohydrology of ephemeral stream systems is an important constraint on paleoclimatic conditions in arid environments, but remains difficult to constrain quantitatively. For example, sedimentary records of the size and extent of pluvial lakes in the Mojave Desert have been used as a proxy for Quaternary climate variability. Although the delivery mechanisms of this additional water...
Authors
Andrew J. Cyr, David M. Miller, Shannon A. Mahan
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Geologic history of the Black Hills caves, South Dakota Geologic history of the Black Hills caves, South Dakota
Cave development in the Madison aquifer of the Black Hills has taken place in several stages. Mississippian carbonates first underwent eogenetic (early diagenetic) reactions with interbedded sulfates to form breccias and solution voids. Later subaerial exposure allowed oxygenated meteoric water to replace sulfates with calcite and to form karst and small caves. All were later buried by...
Authors
Arthur N. Palmer, Margaret Palmer, James B. Paces
A multi-proxy record of hydroclimate, vegetation, fire, and post-settlement impacts for a subalpine plateau, Central Rocky Mountains U.S.A A multi-proxy record of hydroclimate, vegetation, fire, and post-settlement impacts for a subalpine plateau, Central Rocky Mountains U.S.A
Apparent changes in vegetation distribution, fire, and other disturbance regimes throughout western North America have prompted investigations of the relative importance of human activities and climate change as potential causal mechanisms. Assessing the effects of Euro-American settlement is difficult because climate changes occur on multi-decadal to centennial time scales and require...
Authors
Lesleigh Anderson, Andrea Brunelle, Robert S. Thompson
Sea level, paleogeography, and archeology on California's Northern Channel Islands Sea level, paleogeography, and archeology on California's Northern Channel Islands
Sea-level rise during the late Pleistocene and early Holocene inundated nearshore areas in many parts of the world, producing drastic changes in local ecosystems and obscuring significant portions of the archeological record. Although global forces are at play, the effects of sea-level rise are highly localized due to variability in glacial isostatic adjustment (GIA) effects...
Authors
Leslie Reeder-Myers, Jon M. Erlandson, Daniel R. Muhs, Torben C. Rick
Late Quaternary sea-level history and the antiquity of mammoths (Mammuthus exilis and Mammuthus columbi), Channel Islands NationalPark, California, USA Late Quaternary sea-level history and the antiquity of mammoths (Mammuthus exilis and Mammuthus columbi), Channel Islands NationalPark, California, USA
Fossils of Columbian mammoths (Mammuthus columbi) and pygmy mammoths (Mammuthus exilis) have been reported from Channel Islands National Park, California. Most date to the last glacial period (Marine Isotope Stage [MIS] 2), but a tusk of M. exilis (or immature M. columbi) was found in the lowest marine terrace of Santa Rosa Island. Uranium-series dating of corals yielded ages from 83.8 ±...
Authors
Daniel R. Muhs, Kathleen R. Simmons, Lindsey T. Groves, John P. McGeehin, R. Randall Schumann, Larry D. Agenbroad
Forecasting and evaluating patterns of energy development in southwestern Wyoming Forecasting and evaluating patterns of energy development in southwestern Wyoming
The effects of future oil and natural gas development in southwestern Wyoming on wildlife populations are topical to conservation of the sagebrush steppe ecosystem. To aid in understanding these potential effects, the U.S. Geological Survey developed an Energy Footprint simulation model that forecasts the amount and pattern of energy development under different assumptions of development...
Authors
Steven L. Garman
User guide for luminescence sampling in archaeological and geological contexts User guide for luminescence sampling in archaeological and geological contexts
Luminescence dating provides a direct age estimate of the time of last exposure of quartz or feldspar minerals to light or heat and has been successfully applied to deposits, rock surfaces, and fired materials in a number of archaeological and geological settings. Sampling strategies are diverse and can be customized depending on local circumstances, although all sediment samples need to...
Authors
Michelle S. Nelson, Harrison J. Gray, Jack A. Johnson, Tammy M. Rittenour, James K. Feathers, Shannon Mahan
Precise interpolar phasing of abrupt climate change during the last ice age Precise interpolar phasing of abrupt climate change during the last ice age
The last glacial period exhibited abrupt Dansgaard–Oeschger climatic oscillations, evidence of which is preserved in a variety of Northern Hemisphere palaeoclimate archives1. Ice cores show that Antarctica cooled during the warm phases of the Greenland Dansgaard–Oeschger cycle and vice versa2, 3, suggesting an interhemispheric redistribution of heat through a mechanism called the bipolar...
Authors
Christo Buizert, Betty M. Adrian, Jinho Ahn, Mary Albert, Richard B. Alley, Daniel Baggenstos, Thomas K. Bauska, Ryan C. Bay, Brian B. Bencivengo, Charles R. Bentley, Edward J. Brook, Nathan J. Chellman, Gary D. Clow, Jihong Cole-Dai, Howard Conway, Eric Cravens, Kurt M. Cuffey, Nelia W. Dunbar, Jon S. Edwards, John M. Fegyveresi, Dave G. Ferris, Joan J. Fitzpatrick, T. J. Fudge, Chris J. Gibson, Vasileios Gkinis, Joshua J. Goetz, Stephanie Gregory, Geoffrey Mill Hargreaves, Nels Iverson, Jay A. Johnson, Tyler R. Jones, Michael L. Kalk, Matthew J. Kippenhan, Bess G. Koffman, Karl Kreutz, Tanner W. Kuhl, Donald A. Lebar, James E. Lee, Shaun A. Marcott, Bradley R. Markle, Olivia J. Maselli, Joseph R. McConnell, Kenneth C. McGwire, Logan E. Mitchell, Nicolai B. Mortensen, Peter D. Neff, Kunihiko Nishiizumi, Richard M. Nunn, Anais J. Orsi, Daniel R. Pasteris, Joel B. Pedro, Erin C. Pettit, P. Buford Price, John C. Priscu, Rachael H. Rhodes, Julia L. Rosen, Andrew J. Schauer, Spruce W. Schoenemann, Paul J. Sendelbach, Jeffrey P. Severinghaus, Alexander J. Shturmakov, Michael Sigl, Kristina R. Slawny, Joseph M. Souney, Todd A. Sowers, Matthew K. Spencer, Eric J. Steig, Kendrick C. Taylor, Mark S. Twickler, Bruce H. Vaughn, Donald E. Voigt, Edwin D. Waddington, Kees C. Welten, Anthony W. Wendricks, James W. C. White, Mai Winstrup, Gifford J. Wong, Thomas E. Woodruff
Complex terrain alters temperature and moisture limitations of forest soil respiration across a semiarid to subalpine gradient Complex terrain alters temperature and moisture limitations of forest soil respiration across a semiarid to subalpine gradient
Forest soil respiration is a major carbon (C) flux that is characterized by significant variability in space and time. We quantified growing season soil respiration during both a drought year and a nondrought year across a complex landscape to identify how landscape and climate interact to control soil respiration. We asked the following questions: (1) How does soil respiration vary...
Authors
Erin Michele Berryman, H.R. Barnard, H.R. Adams, M.A. Burns, E. Gallo, P. D. Brooks
Digital representation of oil and natural gas well pad scars in southwest Wyoming: 2012 update Digital representation of oil and natural gas well pad scars in southwest Wyoming: 2012 update
The recent proliferation of oil and natural gas energy development in the Greater Green River Basin of southwest Wyoming has accentuated the need to understand wildlife responses to this development. The location and extent of surface disturbance that is created by oil and natural gas well pad scars are key pieces of information used to assess the effects of energy infrastructure on...
Authors
Steven L. Garman, Jamie L. McBeth
Radar attenuation and temperature within the Greenland Ice Sheet Radar attenuation and temperature within the Greenland Ice Sheet
The flow of ice is temperature-dependent, but direct measurements of englacial temperature are sparse. The dielectric attenuation of radio waves through ice is also temperature-dependent, and radar sounding of ice sheets is sensitive to this attenuation. Here we estimate depth-averaged radar-attenuation rates within the Greenland Ice Sheet from airborne radar-sounding data and its...
Authors
Joseph A MacGregor, Jilu Li, John D Paden, Ginny A Catania, Gary D. Clow, Mark A Fahnestock, Prasad S. Gogineni, Robert E. Grimm, Mathieu Morlighem, Soumyaroop Nandi, Helene Seroussi, David E Stillman