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: 2882
Diet energy density estimated from isotopes in predator hair associated with survival, habitat, and population dynamics
Sea ice loss is fundamentally altering the Arctic marine environment. Yet there is a paucity of data on the adaptability of food webs to ecosystem change, including predator-prey interactions. Polar bears (Ursus maritimus) are an important subsistence resource for Indigenous people and an apex predator that relies entirely on the under-ice food web to meet their energy needs. Here, we assessed whe
Authors
Karyn D. Rode, Brian D. Taras, Craig A. Stricker, Todd C. Atwood, Nicole P Boucher, George M. Durner, Andrew E. Derocher, Evan S. Richardson, Seth Cherry, Lori T. Quakenbush, Lara Horstmann, Jeffrey F. Bromaghin
Inventory of eelgrass (Zostera marina) and seaweeds at the end of the Alaska Peninsula, August–September 2012:
Coastal communities in Alaska are undergoing rapid environmental change from increasing temperatures and baseline data are needed to monitor potential impacts. We conducted the first surveys of the abundance and distribution of eelgrass (Zostera marina) and seaweeds in the western part of Izembek National Wildlife Refuge at the end of the Alaska Peninsula. Six embayments and two offshore islands w
Authors
David H. Ward, Kyle R. Hogrefe, Tyronne F. Donnelly, Neils C. Dau, Orville Lind, Kevin J. Payne, Sandra C. Lindstrom
Eelgrass (Zostera marina) and seaweed abundance along the coast of Nunivak Island, Yukon Delta National Wildlife Refuge, Alaska, 2010
Eelgrass (<em>Zostera marina</em>) is a highly productive seagrass that plays an essential role in the health of the estuarine and coastal ecosystems; however, information about its abundance and distribution is insufficient in the Bering Sea along the Yukon Delta National Wildlife Refuge. We inventoried the spatial extent and abundance of eelgrass and seaweed in Duchikthluk and Shoal bays on Nuni
Authors
David H. Ward, Kyle R. Hogrefe, Tyrone F. Donnelly, Lucretia L. Fairchild
Eelgrass (Zostera marina) and Seaweed Abundance along the Coast of Togiak National Wildlife Refuge, Alaska, 2008–10
We conducted a point-sampling survey to determine eelgrass (Zostera marina) and seaweed abundance in coastal waters adjacent to Togiak National Wildlife Refuge, Alaska, in July 2008–10. Eelgrass was known to be abundant in protected embayments of the southeastern Bering Sea and near the Togiak National Wildlife Refuge, but prior to this study, no systematic ground surveys had been conducted in the
Authors
David H. Ward, Kyle R. Hogrefe, Michael A. Swaim, Tyronne F. Donnelly, Lucretia L. Fairchild
Distribution of eelgrass (Zostera marina) in coastal waters adjacent to Togiak National Wildlife Refuge, Alaska
Declines in the distribution and abundance of seagrasses worldwide have prompted a need for baseline distribution maps of eelgrass (Zostera marina) in Alaska. We used high-resolution digital-color aerial photography and multi-spectral satellite imagery to map the distribution and spatial extent of eelgrass at 21 sites in coastal waters adjacent to Togiak National Wildlife Refuge (TNWR) in northwes
Authors
David H. Ward, Kyle R. Hogrefe, Tyronne F. Donnelly, Michael A. Swaim
Abundance and distribution of eelgrass (Zostera marina) and seaweeds at Izembek National Wildlife Refuge, Alaska, 2007–10
Eelgrass (Zostera marina) meadows are expansive along the lower Alaska Peninsula, supporting a rich diversity of marine life, yet little is known about their status and trends in the region. We tested techniques to inventory and monitor trends in the spatial extent and abundance of eelgrass in lagoons of the Izembek National Wildlife Refuge. We determined if Landsat imagery could be used to assess
Authors
David H. Ward, Kyle R. Hogrefe, Tyronne F. Donnelly, Lucretia L. Fairchild, Kristine M. Sowl, Sandra C. Lindstrom
Estimating Pacific walrus abundance and survival with multievent mark-recapture models
Arctic marine ecosystems are undergoing rapid physical and biological change associated with climate warming and loss of sea ice. Sea ice loss will impact many species through altered spatial and temporal availability of resources. In the Bering and Chukchi Seas, the Pacific walrus Odobenus rosmarus divergens is one species that could be impacted by rapid environmental change, and thus, population
Authors
William S. Beatty, Patrick R. Lemons, Jason P. Everett, Cara J. Lewis, Rebecca L. Taylor, Robert J. Lynn, Suresh A. Sethi, Lori T. Quakenbush, John J. Citta, Michelle Kissling, Natalia Kryukova, John K. Wennburg
Wildlife population dynamics
In this chapter we provide an overview of some core concepts, describe exponential growth as the basic foundation for understanding population dynamics, and discuss some of the factors that can affect wildlife population dynamics. We then show how management insights that can be gained from analyzing the dynamics of individual age or stage classes, examine dynamics of multiple populations across a
Authors
L. Scott Mills, Heather E. Johnson
Survival and reproduction in Arctic caribou are associated with summer forage and insect harassment
Investigators have speculated that the climate-driven “greening of the Arctic” may benefit barren-ground caribou populations, but paradoxically many populations have declined in recent years. This pattern has raised concerns about the influence of summer habitat conditions on caribou demographic rates, and how populations may be impacted in the future. The short Arctic summer provides caribou with
Authors
Heather E. Johnson, Beth Lenart, Dave Gustine, Layne G. Adams, Perry Barboza
Avian influenza antibody prevalence increases with mercury contamination in wild waterfowl
Environmental contamination is widespread and can negatively impact wildlife health. Some contaminants, including heavy metals, have immunosuppressive effects, but prior studies have rarely measured contamination and disease simultaneously, which limits our understanding of how contaminants and pathogens interact to influence wildlife health. Here, we measured mercury concentrations, influenza inf
Authors
Claire Stewart Teitelbaum, Josh T. Ackerman, Mason A. Hill, Jaqueline M. Satter, Michael L. Casazza, Susan E. W. De La Cruz, Walter M. Boyce, Evan James Buck, John M. Eadie, Mark P. Herzog, Elliott Matchett, Cory T. Overton, Sarah H. Peterson, Magdalena Plancarte, Andrew M. Ramey, Jeffery D. Sullivan, Diann Prosser
Modeling the spatial and temporal dynamics of land-based polar bear denning in Alaska
Although polar bears (Ursus maritimus) of the Southern Beaufort Sea (SBS) subpopulation have commonly created maternal dens on sea ice in the past, maternal dens on land have become increasingly prevalent as sea ice declines. This trend creates conditions for increased human–bear interactions associated with local communities and industrial activity. Maternal denning is a vulnerable period in the
Authors
Vijay P. Patil, George M. Durner, David C. Douglas, Todd C. Atwood
In hot water? Patterns of macroinvertebrate abundance in Arctic thaw ponds and relationships with environmental variables
Ongoing environmental change across the Arctic is affecting many freshwater ecosystems, including small thaw ponds that support macroinvertebrates, thus potentially affecting important forage for fish and bird species. To accurately predict how fish and wildlife that depend on these macroinvertebrates will be affected by ecosystem change at high latitudes, understanding proximate factors that infl
Authors
Kirsty E. B. Gurney, Joshua C. Koch, Joel A. Schmutz, J. H. Schmidt, Mark S. Wipfli