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Page 60, results 1476 - 1500

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Not all publications have extents, not all extents are completely accurate
PeRL: A circum-Arctic Permafrost Region Pond and Lake database
Sina Muster, Kurt Roth, Moritz Langer, Stephan Lange, Fabio Cresto Aleina, Annett Bartsch, Anne Morgenstern, Guido Grosse, Benjamin M. Jones, A. B. K. Sannel, Ylva Sjöberg, Frank Gunther, Christian Andresen, Alexandra Veremeeva, Prajna R. Lindgren, Frédéric Bouchard, Mark J. Lara, Daniel Fortier, Simon Charbonneau, Tarmo A. Virtanen, Gustaf Hugelius, J. Palmtag, Matthias B. Siewert, William J. Riley, Charles Koven, Julia Boike
2017, Earth System Science Data (9) 317-348
Ponds and lakes are abundant in Arctic permafrost lowlands. They play an important role in Arctic wetland ecosystems by regulating carbon, water, and energy fluxes and providing freshwater habitats. However, ponds, i.e., waterbodies with surface areas smaller than 1. 0 × 104 m2, have not been inventoried on global and regional scales. The Permafrost...
Decadal declines in avian herbivore reproduction: density-dependent nutrition and phenological mismatch in the Arctic
Megan V. Ross, Ray T. Alisaukas, David C. Douglas, Dana K. Kellett
2017, Ecology (98) 1869-1883
A full understanding of population dynamics depends not only on estimation of mechanistic contributions of recruitment and survival, but also knowledge about the ecological processes that drive each of these vital rates. The process of recruitment in particular may be protracted over several years, and can depend on numerous ecological...
Glacierized headwater streams as aquifer recharge corridors, subarctic Alaska
Anna K. Lilledahl, Anne Gadeke, Shad O'Neel, T. A. Gatesman, T. A. Douglas
2017, Geophysical Research Letters (44) 6876-6885
Arctic river discharge has increased in recent decades although sources and mechanisms remain debated. Abundant literature documents permafrost thaw and mountain glacier shrinkage over the past decades. Here we link glacier runoff to aquifer recharge via a losing headwater stream in subarctic Interior Alaska. Field measurements in Jarvis Creek (634 km2),...
Autonomous acoustic recorders reveal complex patterns in avian detection probability
Sarah J. Thompson, Colleen M. Handel, Lance B. McNew
2017, Journal of Wildlife Management (81) 1228-1241
Avian point‐count surveys are typically designed to occur during periods when birds are consistently active and singing, but seasonal and diurnal patterns of detection probability are often not well understood and may vary regionally or between years. We deployed autonomous acoustic recorders to assess how avian availability for detection (i.e.,...
Genetic assessment of the effects of streamscape succession on coho salmon Oncorhynchus kisutch colonization in recently deglaciated streams
Kim T. Scribner, Chad Soiseth, Jeffrey J. McGuire, G. Kevin Sage, Lyman K. Thorsteinson, J. L. Nielsen, E. Knudsen
2017, Journal of Fish Biology (91) 195-218
Measures of genetic diversity within and among populations and historical geomorphological data on stream landscapes were used in model simulations based on approximate Bayesian computation (ABC) to examine hypotheses of the relative importance of stream features (geomorphology and age) associated with colonization events and gene flow for coho salmon Oncorhynchus kisutch breeding...
Landsat-based trend analysis of lake dynamics across northern permafrost regions
Ingmar Nitze, Guido Grosse, Benjamin M. Jones, Christopher D. Arp, Mathias Ulrich, Alexander Federov, Alexandra Veremeeva
2017, Remote Sensing (9)
Lakes are a ubiquitous landscape feature in northern permafrost regions. They have a strong impact on carbon, energy and water fluxes and can be quite responsive to climate change. The monitoring of lake change in northern high latitudes, at a sufficiently accurate spatial and temporal resolution, is crucial for understanding...
New methodology for computing tsunami generation by subaerial landslides: Application to the 2015 Tyndall Glacier landslide, Alaska
David L. George, Richard M. Iverson, Charles M. Cannon
2017, Geophysical Research Letters (44) 7276-7284
Landslide-generated tsunamis pose significant hazards and involve complex, multiphase physics that are challenging to model. We present a new methodology in which our depth-averaged two-phase model D-Claw is used to seamlessly simulate all stages of landslide dynamics as well as tsunami generation, propagation, and inundation. Because the model describes the...
Younger-Dryas cooling and sea-ice feedbacks were prominent features of the Pleistocene-Holocene transition in Arctic Alaska
Benjamin V. Gaglioti, Daniel H. Mann, Matthew J. Wooller, Benjamin M. Jones, Gregory C. Wiles, Pamela Groves, Michael L. Kunz, Carson Baughman, Richard E. Reanier
2017, Quaternary Science Reviews (169) 330-343
Declining sea-ice extent is currently amplifying climate warming in the Arctic. Instrumental records at high latitudes are too short-term to provide sufficient historical context for these trends, so paleoclimate archives are needed to better understand the functioning of the sea ice-albedo feedback. Here we use the oxygen isotope values of...
A genetic signature of the evolution of loss of flight in the Galapagos cormorant
Alejandro Burga, Weiguang Wang, Eyal Ben-David, Paul C. Wolf, Andrew M. Ramey, Claudio Verdugo, Karen Lyons, Patricia G. Parker, Leonid Kruglyak
2017, Science (356)
INTRODUCTIONChanges in the size and proportion of limbs and other structures have played a key role in the evolution of species. One common class of limb modification is recurrent wing reduction and loss of flight in birds. Indeed, Darwin used the occurrence of flightless birds as an...
Expanding the North American Breeding Bird Survey analysis to include additional species and regions
John R. Sauer, Daniel Niven, Keith Pardieck, David Ziolkowski Jr., William A. Link
2017, Journal of Fish and Wildlife Management (8) 154-172
The North American Breeding Bird Survey (BBS) contains data for >700 bird species, but analyses often focus on a core group of ∼420 species. We analyzed data for 122 species of North American birds for which data exist in the North American Breeding Bird Survey (BBS) database but are not...
Migration trends of Sockeye Salmon at the northern edge of their distribution
Michael P. Carey, Christian E. Zimmerman, Kevin D. Keith, Merlyn Schelske, Charles Lean, David C. Douglas
2017, Transactions of the American Fisheries Society (146) 791-802
Climate change is affecting arctic and subarctic ecosystems, and anadromous fish such as Pacific salmon Oncorhynchus spp. are particularly susceptible due to the physiological challenge of spawning migrations. Predicting how migratory timing will change under Arctic warming scenarios requires an understanding of how environmental factors drive salmon migrations. Multiple mechanisms...
Nest-site selection and nest success of an Arctic-breeding passerine, Smith's Longspur, in a changing climate
Heather R. McFarland, Steve J. Kendall, Abby Powell
2017, The Condor (119) 85-97
Despite changes in shrub cover and weather patterns associated with climate change in the Arctic, little is known about the breeding requirements of most passerines tied to northern regions. We investigated the nesting biology and nest habitat characteristics of Smith's Longspurs (Calcarius pictus) in 2 study areas in the Brooks...
Duckling survival of mallards in Southland, New Zealand
Erin Garrick, Courtney L. Amundson, Phillip J. Seddon
2017, Journal of Wildlife Management (81) 858-867
The southern portion of New Zealand's South Island is a productive area for mallards (Anas platyrhynchos) despite a notable lack of permanent or semi-permanent wetlands. Most broods are reared in pastures that may or may not be flooded with ephemeral water. In recent years, there has been an increased conversion...
System identification based on deconvolution and cross correlation: An application to a 20‐story instrumented building in Anchorage, Alaska
Weiping Wen, Erol Kalkan
2017, Bulletin of the Seismological Society of America (107) 718-740
Deconvolution and cross‐correlation techniques are used for system identification of a 20‐story steel, moment‐resisting frame building in downtown Anchorage, Alaska. This regular‐plan midrise structure is instrumented with a 32‐channel accelerometer array at 10 levels. The impulse response functions (IRFs) and correlation functions (CFs) are computed based on waveforms recorded from...
Snow and ice
Jeremy S. Littell, Stephanie A. McAfee, Shad O'Neel, Louis C. Sass, Evan Burgess, Steve Colt, Paul Clark
Gregory D. Hayward, Steve Colt, Monica L. McTeague, Teresa N. Hollingsworth, editor(s)
2017, General Technical Report PNW-GTR-950-3
Temperature and precipitation are key determinants of snowpack levels. Therefore, climate change is likely to affect the role of snow and ice in the landscapes and hydrology of the Chugach National Forest region.Downscaled climate projections developed by Scenarios Network for Alaska and Arctic Planning (SNAP) are useful for examining projected...
Seasonal and spatial variabilities in northern Gulf of Alaska surface water iron concentrations driven by shelf sediment resuspension, glacial meltwater, a Yakutat eddy, and dust
John Crusius, Andrew W. Schroth, Joseph A. Resing, Jay Cullen, Robert W. Campbell
2017, Global Biogeochemical Cycles (31) 942-960
Phytoplankton growth in the Gulf of Alaska (GoA) is limited by iron (Fe), yet Fe sources are poorly constrained. We examine the temporal and spatial distributions of Fe, and its sources in the GoA, based on data from three cruises carried out in 2010 from the Copper River (AK) mouth...
Reflected stochastic differential equation models for constrained animal movement
Ephraim M. Hanks, Devin S. Johnson, Mevin Hooten
2017, Journal of Agricultural, Biological, and Environmental Statistics (22) 353-372
Movement for many animal species is constrained in space by barriers such as rivers, shorelines, or impassable cliffs. We develop an approach for modeling animal movement constrained in space by considering a class of constrained stochastic processes, reflected stochastic differential equations. Our approach generalizes existing methods for modeling unconstrained animal...
Uncertainties in forecasting the response of polar bears to global climate change
David C. Douglas, Todd C. Atwood
Andy Butterworth, editor(s)
2017, Book chapter, Marine animal welfare
Several sources of uncertainty affect how precisely the future status of polar bears (Ursus maritimus) can be forecasted. Foremost are unknowns about the future levels of global greenhouse gas emissions, which could range from an unabated increase to an aggressively mitigated reduction. Uncertainties also arise because different climate...
Seasonal movements of the Short-eared Owl (Asio flammeus) in western North America as revealed by satellite telemetry
James A. Johnson, Travis L. Booms, Lucas H. DeCicco, David C. Douglas
2017, Journal of Raptor Research (51) 115-128
The Short-eared Owl (Asio flammeus) is a widespread raptor whose abundance and distribution fluctuates in response to the varying amplitudes of its prey, which are predominately microtines. Previous efforts to describe the seasonal movements of Short-eared Owls have been hindered by few band recoveries and the species' cryptic and irruptive...
A decade of boreal rich fen greenhouse gas fluxes in response to natural and experimental water table variability
David Olefeldt, Eugénie S. Euskirchen, Jennifer W. Harden, Evan S. Kane, A. David McGuire, Mark P. Waldrop, Merritt R. Turetsky
2017, Global Change Biology (23) 2428-2440
Rich fens are common boreal ecosystems with distinct hydrology, biogeochemistry and ecology that influence their carbon (C) balance. We present growing season soil chamber methane emission (FCH4), ecosystem respiration (ER), net ecosystem exchange (NEE) and gross primary production (GPP) fluxes from a 9-years water table manipulation experiment in an Alaskan...
A land cover change detection and classification protocol for updating Alaska NLCD 2001 to 2011
Suming Jin, Limin Yang, Zhe Zhu, Collin G. Homer
2017, Remote Sensing of Environment (195) 44-55
Monitoring and mapping land cover changes are important ways to support evaluation of the status and transition of ecosystems. The Alaska National Land Cover Database (NLCD) 2001 was the first 30-m resolution baseline land cover product of the entire state derived from circa 2001 Landsat imagery and geospatial ancillary data....
Ecological change drives a decline in mercury concentrations in southern Beaufort Sea polar bears
Melissa A. McKinney, Todd C. Atwood, Sara Pedro, Elizabeth L. Peacock
2017, Environmental Science & Technology (51) 7814-7822
We evaluated total mercury (THg) concentrations and trends in polar bears from the southern Beaufort Sea subpopulation from 2004 to 2011. Hair THg concentrations ranged widely among individuals from 0.6 to 13.3 μg g–1 dry weight (mean: 3.5 ± 0.2 μg g–1). Concentrations differed among sex and age classes: solitary adult...
Sculpted by water, elevated by earthquakes—The coastal landscape of Glacier Bay National Park, Alaska
Robert C. Witter, Adam LeWinter, Adrian M. Bender, Craig Glennie, David C. Finnegan
2017, General Information Product 177
Within Glacier Bay National Park in southeastern Alaska, the Fairweather Fault represents the onshore boundary between two of Earth’s constantly moving tectonic plates: the North American Plate and the Yakutat microplate. Satellite measurements indicate that during the past few decades the Yakutat microplate has moved northwest at a rate of...
The role of density-dependent and –independent processes in spawning habitat selection by salmon in an Arctic riverscape
Brock M. Huntsman, Jeffrey A. Falke, James W. Savereide, Katrina E. Bennett
2017, PLoS ONE (12) 1-21
Density-dependent (DD) and density-independent (DI) habitat selection is strongly linked to a species’ evolutionary history. Determining the relative importance of each is necessary because declining populations are not always the result of altered DI mechanisms but can often be the result of DD via a reduced carrying capacity. We developed...
Habitat degradation affects the summer activity of polar bears
Jasmine V. Ware, Karyn D. Rode, Jeffrey F. Bromaghin, David C. Douglas, Ryan H. Wilson, Eric V. Regehr, Steven C. Amstrup, George M. Durner, Anthony M. Pagano, Jay Olson, Charles T. Robbins, Heiko T Jansen
2017, Oecologia (184) 87-99
Understanding behavioral responses of species to environmental change is critical to forecasting population-level effects. Although climate change is significantly impacting species’ distributions, few studies have examined associated changes in behavior. Polar bear (Ursus maritimus) subpopulations have varied in their near-term responses to sea ice decline. We examined behavioral...