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Science Quality and Integrity
The USGS provides unbiased, objective, and impartial scientific information upon which our audiences, including resource managers, planners, and other entities, rely.
The USGS provides unbiased, objective, and impartial scientific information upon which our audiences, including resource managers, planners, and other entities, rely.
Browse more than 82,000 reports 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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Statement of Dr. Craig D. Allen, U.S. Geological Survey, Department of the Interior, before the Committee on Energy and Natural Resources, U.S. Senate, 17 August 2012 Statement of Dr. Craig D. Allen, U.S. Geological Survey, Department of the Interior, before the Committee on Energy and Natural Resources, U.S. Senate, 17 August 2012
No abstract available.
Authors
Craig D. Allen
Statewide summary for Texas Statewide summary for Texas
The Texas coast (Figure 1) consists of complex and diverse ecosystems with a varying precipitation gradient. The northernmost portion of the coast, extending from Sabine Lake to Galveston Bay, is composed of salt, brackish, intermediate, and fresh marshes, with humid flatwoods inland (Moulton and others, 1997). Coastal prairies are found across the entire coast. From Galveston Bay to...
Authors
Lawrence R. Handley, Kathryn A. Spear, Jim Gibeaut, Cindy A. Thatcher
Statistical analyses to support guidelines for marine avian sampling. Final report Statistical analyses to support guidelines for marine avian sampling. Final report
Interest in development of offshore renewable energy facilities has led to a need for high-quality, statistically robust information on marine wildlife distributions. A practical approach is described to estimate the amount of sampling effort required to have sufficient statistical power to identify species-specific “hotspots” and “coldspots” of marine bird abundance and occurrence in an...
Authors
Brian P. Kinlan, Elise Zipkin, Allan F. O’Connell, Chris Caldow
Statistical relations of salt and selenium loads to geospatial characteristics of corresponding subbasins of the Colorado and Gunnison Rivers in Colorado Statistical relations of salt and selenium loads to geospatial characteristics of corresponding subbasins of the Colorado and Gunnison Rivers in Colorado
Elevated loads of salt and selenium can impair the quality of water for both anthropogenic and natural uses. Understanding the environmental processes controlling how salt and selenium are introduced to streams is critical to managing and mitigating the effects of elevated loads. Dominant relations between salt and selenium loads and environmental characteristics can be established by...
Authors
Kenneth J. Leib, Joshua I. Linard, Cory A. Williams
Status and limiting factors of two rare plant species in dry montane communities of Hawai`i Volcanoes National Park. Status and limiting factors of two rare plant species in dry montane communities of Hawai`i Volcanoes National Park.
Two rare plants native to montane dry forests and woodland communities of Hawai`i Volcanoes National Park (HAVO) were studied for more than two years to determine their stand structure, short-term mortality rates, patterns of reproductive phenology, success of fruit production, floral visitor composition, seed germination rates in the greenhouse, and survival of both natural and planted...
Authors
Linda W. Pratt, Joshua R. VanDeMark, Melody Euaparadorn
Status and trends in the fish community of Lake Superior, 2012 Status and trends in the fish community of Lake Superior, 2012
The Great Lakes Science Center has conducted daytime nearshore bottom trawl surveys of Lake Superior (15-80 m bathymetric depth zone) each spring since 1978 and an offshore survey (>80 m) since 2011 to provide long-term trends of relative abundance and biomass of the fish community. In 2012, 72 nearshore and 34 offshore stations were sampled with a 12-m Yankee bottom trawl. The 2012...
Authors
Owen T. Gorman, Lori M. Evrard, Gary A. Cholwek, Mark R. Vinson
Status and trends of land change in the United States--1973 to 2000 Status and trends of land change in the United States--1973 to 2000
Authors
Water Resources Division U.S. Geological Survey
Status and trends of pelagic prey fishes in Lake Huron, 2012 Status and trends of pelagic prey fishes in Lake Huron, 2012
The USGS Great Lakes Science Center (GLSC) conducted acoustic/midwater trawl surveys of Lake Huron during 1997 and annually during 2004-2012. The 2012 survey was conducted during September and October, and included transects in Lake Huron’s Main Basin, Georgian Bay, and North Channel. Pelagic fish density (638 fish/ha) was lower in 2012 compared to 2011, with density in 2012 only 34% of...
Authors
David M. Warner, Timothy P. O’Brien, Steven A. Farha, Jeff Schaeffer, Stephen Lenart
Status and trends of prey fish populations in Lake Michigan, 2012 Status and trends of prey fish populations in Lake Michigan, 2012
The U.S. Geological Survey Great Lakes Science Center has conducted lake-wide surveys of the fish community in Lake Michigan each fall since 1973 using standard 12-m bottom trawls towed along contour at depths of 9 to 110 m at each of seven index transects. The resulting data on relative abundance, size and age structure, and condition of individual fishes are used to estimate various...
Authors
David B. Bunnell, Charles P. Madenjian, Timothy J. Desorcie, Melissa Jean Kostich, Kelley Smith, Jean V. Adams
Status and trends of the land bird avifauna on Tinian and Aguiguan, Mariana Islands Status and trends of the land bird avifauna on Tinian and Aguiguan, Mariana Islands
Avian surveys were conducted on the islands of Tinian and Aguiguan, Marianas Islands, in 2008 by the U.S. Fish and Wildlife Service to provide current baseline densities and abundances and assess population trends using data collected from previous surveys. On Tinian, during the three surveys (1982, 1996, and 2008), 18 species were detected, and abundances and trends were assessed for 12...
Authors
Richard J. Camp, Thane K. Pratt, Fred Amidon, Ann P. Marshall, Shelly Kremer, Megan Laut
Status and understanding of groundwater quality in the Tahoe-Martis, Central Sierra, and Southern Sierra study units, 2006-2007--California GAMA Priority Basin Project Status and understanding of groundwater quality in the Tahoe-Martis, Central Sierra, and Southern Sierra study units, 2006-2007--California GAMA Priority Basin Project
Groundwater quality in the Tahoe-Martis, Central Sierra, and Southern Sierra study units was investigated as part of the Priority Basin Project of the California Groundwater Ambient Monitoring and Assessment (GAMA) Program. The three study units are located in the Sierra Nevada region of California in parts of Nevada, Placer, El Dorado, Madera, Tulare, and Kern Counties. The GAMA...
Authors
Miranda S. Fram, Kenneth Belitz