Publications
USGS research activities relevant to Alaska have yielded more than 9400 historical publications. This page features some of the most recent newsworthy research findings.
Filter Total Items: 3082
Influence of landscape structure, topography, and forest type on spatial variation in historical fire regimes, central Oregon, USA Influence of landscape structure, topography, and forest type on spatial variation in historical fire regimes, central Oregon, USA
Context In the interior Northwest, debate over restoring mixed-conifer forests after a century of fire exclusion is hampered by poor understanding of the pattern and causes of spatial variation in historical fire regimes. Objectives To identify the roles of topography, landscape structure, and forest type in driving spatial variation in historical fire regimes in mixed-conifer forests of
Authors
Andrew Merschel, Emily K. Heyerdahl, Thomas A. Spies, Rachel A. Loehman
Effect of climate change on disease spread in wildlife Effect of climate change on disease spread in wildlife
A growing body of evidence indicates that climate change alone, or acting synergistically with current anthropogenic threats, is affecting the health of wild populations of aquatic and terrestrial wildlife. Measurable by-products of climate change include elevated atmospheric concentrations of greenhouse gases, higher average global temperatures; variations in global precipitation...
Authors
Erik K. Hofmeister, Caroline R. Van Hemert
Sulfur isotopes of host strata for Howards Pass (Yukon–Northwest Territories) Zn-Pb deposits implicate anaerobic oxidation of methane, not basin stagnation Sulfur isotopes of host strata for Howards Pass (Yukon–Northwest Territories) Zn-Pb deposits implicate anaerobic oxidation of methane, not basin stagnation
A new sulfur isotope stratigraphic profile has been developed for Ordovician-Silurian mudstones that host the Howards Pass Zn-Pb deposits (Canada) in an attempt to reconcile the traditional model of a stagnant euxinic basin setting with new contradictory findings. Our analyses of pyrite confirm the up-section 34S enrichment reported previously, but additional observations show parallel...
Authors
Craig A. Johnson, John F. Slack, Julie A. Dumoulin, Karen Duttweiler Kelley, Hendrik Falck
Using stereo satellite imagery to account for ablation, entrainment, and compaction in volume calculations for rock avalanches on Glaciers: Application to the 2016 Lamplugh Rock Avalanche in Glacier Bay National Park, Alaska Using stereo satellite imagery to account for ablation, entrainment, and compaction in volume calculations for rock avalanches on Glaciers: Application to the 2016 Lamplugh Rock Avalanche in Glacier Bay National Park, Alaska
The use of preevent and postevent digital elevation models (DEMs) to estimate the volume of rock avalanches on glaciers is complicated by ablation of ice before and after the rock avalanche, scour of material during rock avalanche emplacement, and postevent ablation and compaction of the rock avalanche deposit. We present a model to account for these processes in volume estimates of rock
Authors
Erin Bessette-Kirton, Jeffrey A. Coe, Wendy Zhou
Evidence for haemosporidian parasite infections in Spectacled Eiders (Somateria fischeri) sampled in Alaska during the breeding season Evidence for haemosporidian parasite infections in Spectacled Eiders (Somateria fischeri) sampled in Alaska during the breeding season
We assessed hematozoa infection in Spectacled Eiders (Somateria fischeri) at two areas in Alaska. No Haemoproteus or Plasmodium species were detected. Leucocytozoon prevalence was 6.5% for adults across sites and 41.9% for juveniles sampled in the Arctic, providing evidence for local transmission. All Leucocytozoon haplotypes were previously detected in waterfowl.
Authors
John A. Reed, Matthew G. Sexson, Matthew M. Smith, Joel A. Schmutz, Andrew M. Ramey
Avian keratin disorder of Alaska black-capped chickadees is associated with Poecivirus infection Avian keratin disorder of Alaska black-capped chickadees is associated with Poecivirus infection
Background Avian keratin disorder (AKD) is an epizootic of debilitating beak deformities, first documented in black-capped chickadees (Poecile atricapillus) in Alaska during the late 1990s. Similar deformities have now been recorded in dozens of species of birds across multiple continents. Despite this, the etiology of AKD has remained elusive, making it difficult to assess the impacts...
Authors
Maxine Zylberberg, Caroline R. Van Hemert, Colleen M. Handel, Joseph L. DeRisi
Energetic costs of locomotion in bears: is plantigrade locomotion energetically economical? Energetic costs of locomotion in bears: is plantigrade locomotion energetically economical?
Ursids are the largest mammals to retain a plantigrade posture. This primitive posture has been proposed to result in reduced locomotor speed and economy relative to digitigrade and unguligrade species, particularly at high speeds. Previous energetics research on polar bears (Ursus maritimus) found locomotor costs were more than double predictions for similarly sized quadrupedal mammals...
Authors
Anthony M. Pagano, Anthony M. Carnahan, Charles T. Robbins, Megan A. Owen, Tammy Batson, Nate Wagner, Amy Cutting, Nicole Nicassio-Hiskey, Amy Hash, Terrie M. Williams
Evolving environmental and geometric controls on Columbia Glacier’s continued retreat Evolving environmental and geometric controls on Columbia Glacier’s continued retreat
Geometry strongly controls the dynamic behavior of marine‐terminating (tidewater) glaciers, significantly influencing advance and retreat cycles independent of climate. Yet the recent, nearly ubiquitous retreat of tidewater glaciers suggests that changes in atmospheric and oceanic forcing may also drive dynamic change. To isolate the influence of geometry on tidewater glacier dynamics...
Authors
Ellyn Enderlin, Shad O’Neel, Timothy C. Bartholomaus, Ian Joughin
Ongoing bedrock incision of the Fortymile River driven by Pliocene–Pleistocene Yukon River capture, eastern Alaska, USA, and Yukon, Canada Ongoing bedrock incision of the Fortymile River driven by Pliocene–Pleistocene Yukon River capture, eastern Alaska, USA, and Yukon, Canada
Quantification of river incision via process rate laws represents a key goal of geomorphic research, but such models often fail to reproduce traits of natural rivers responding to base-level lowering. The Fortymile River flows from eastern Alaska in the United States to the Yukon River in Canada across a tectonically quiescent region with near-uniform precipitation and bedrock erosivity...
Authors
Adrian Bender, Richard O. Lease, Lee B. Corbett, Paul R. Bierman, Marc Caffee
Mean composite fire severity metrics computed with Google Earth Engine offer improved accuracy and expanded mapping potential Mean composite fire severity metrics computed with Google Earth Engine offer improved accuracy and expanded mapping potential
Landsat-based fire severity datasets are an invaluable resource for monitoring and research purposes. These gridded fire severity datasets are generally produced with pre-and post-fire imagery to estimate the degree of fire-induced ecological change. Here, we introduce methods to produce three Landsat-based fire severity metrics using the Google Earth Engine (GEE) platform: the delta...
Authors
Sean Parks, Lisa M. Holsinger, Morgan Voss, Rachel A. Loehman, Nathaniel P. Robinson
Variation in age ratio of midcontinent greater white-fronted geese during fall migration Variation in age ratio of midcontinent greater white-fronted geese during fall migration
Annual productivity is an important parameter for the management of waterfowl populations. Fall age ratio (juveniles:total birds) is an index of productivity of the preceding breeding season. However, differences in the timing of migration between family groups and nonbreeding birds may bias age-ratio estimates. We examined temporal variation in age ratios of midcontinent greater white...
Authors
Wade G. Schock, Julian B. Fischer, Craig R. Ely, Robert A. Stehn, Jeffery M. Welker, Douglas Causey
A multi-species synthesis of satellite telemetry data in the Pacific Arctic (1987–2015): Overlap of marine mammal distributions and core use areas A multi-species synthesis of satellite telemetry data in the Pacific Arctic (1987–2015): Overlap of marine mammal distributions and core use areas
We collated available satellite telemetry data for six species of ice-associated marine mammals in the Pacific Arctic: ringed seals (Pusa hispida; n = 118), bearded seals(Erignathus barbatus, n = 51), spotted seals (Phoca largha, n = 72), Pacific walruses (Odobenus rosmarus divergens, n = 389); bowhead whales (Balaena mysticetus, n = 46), and five Arctic and sub-arctic stocks of beluga...
Authors
John J. Citta, Lloyd F. Lowry, Lori T. Quakenbush, Brendan P. Kelly, Anthony S. Fischbach, Josh M. London, Chadwick V. Jay, Kathryn J. Frost, Gregory O’Corry Crowe, Justin A. Crawford, Peter L. Boveng, Michael Cameron, Andrew L. Von Duyke, Mark Nelson, Lois A. Harwood, Pierre Richard, Robert Suydam, Mads Peter Heide-Jorgensen, Roderick C. Hobbs, Dennis I. Litovka, Marianne Marcoux, Alex Whiting, Amy S. Kennedy, John C. George, Jack Orr, Tom Gray