Are Eastern Monarch Butterflies at Risk of Extinction?
Long-term declines in their overwintering populations are increasing the likelihood of extinction, according to a new study in Scientific ReportsRead more
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We help our scientists partner with governments, NGOs, universities, and individuals in other countries to conduct research that benefits the partner country and the United States. These partnerships can enhance the science and improve diplomatic relationships (science diplomacy), a less tangible but equally important benefit.
Bald eagle predation on common loon egg
The Common Loon (Gavia immer) must defend against many potential egg predators during incubation, including corvids, Herring Gulls (Larus argentatus), raccoons (Procyon lotor), striped skunk (Mephitis mephitis), fisher (Martes pennanti), and mink (Neovison vison) (McIntyre 1988, Evers 2004, McCann et al. 2005). Bald Eagles (Haliaeetus...DeStefano, Stephen; McCarthy, Kyle P.; Laskowski, Tom
King eider use an income strategy for egg production: a case study for incorporating individual dietary variation into nutrient allocation research
The use of stored nutrients for reproduction represents an important component of life-history variation. Recent studies from several species have used stable isotopes to estimate the reliance on stored body reserves in reproduction. Such approaches rely on population-level dietary endpoints to characterize stored reserves (“capital”)...Oppel, Steffen; Powell, Abby N.; O'Brien, Diane M.
Kittlitz's and Marbled Murrelets in Kenai Fjords National Park, South-Central Alaska: At-Sea Distribution, Abundance, and Foraging Habitat, 2006-08
Kittlitz's murrelets (Brachyramphus brevirostris) and marbled murrelets (B. marmoratus) are small diving seabirds and are of management concern because of population declines in coastal Alaska. In 2006-08, we conducted a study in Kenai Fjords National Park, south-central Alaska, to estimate the recent population size of Brachyramphus murrelets, to...Arimitsu, M.L.; Piatt, John F.; Romano, Marc D.; Madison, E.N.; Conaway, J.S.
Arctic sea ice decline: Projected changes in timing and extent of sea ice in the Bering and Chukchi Seas
The Arctic region is warming faster than most regions of the world due in part to increasing greenhouse gases and positive feedbacks associated with the loss of snow and ice cover. One consequence has been a rapid decline in Arctic sea ice over the past 3 decades?a decline that is projected to continue by state-of-the-art models. Many stakeholders...Douglas, D.C.
Characteristics of fall chum salmon spawning habitat on a mainstem river in Interior Alaska
Chum salmon (Oncorhynchus keta) are the most abundant species of salmon spawning in the Yukon River drainage system, and they support important personal use, subsistence, and commercial fisheries. Chum salmon returning to the Tanana River in Interior Alaska are a significant contribution to the overall abundance of Yukon River chum salmon and an...Burril, Sean E.; Zimmerman, Christian E.; Finn, James E.
Alaska’s changing fire regime - Implications for the vulnerability of its boreal forests
A synthesis was carried out to examine Alaska’s boreal forest fire regime. During the 2000s, an average of 767 000 ha·year–1 burned, 50% higher than in any previous decade since the 1940s. Over the past 60 years, there was a decrease in the number of lightning-ignited fires, an increase in extreme lightning-ignited fire...Kasischke, Eric S.; Verbyla, David L.; Rupp, T. Scott; McGuire, Anthony; Murphy, Karen A.; Jandt, R.; Barnes, Jennifer L.; Hoy, E.; Duffy, Paul A; Calef, Monika; Turetsky, Merritt R.
Resilience of Alaska’s boreal forest to climatic change
This paper assesses the resilience of Alaska’s boreal forest system to rapid climatic change. Recent warming is associated with reduced growth of dominant tree species, plant disease and insect outbreaks, warming and thawing of permafrost, drying of lakes, increased wildfire extent, increased postfire recruitment of deciduous trees, and...Chapin, F.S.; McGuire, Anthony; Ruess, Roger W.; Hollingsworth, Teresa N.; Mack, M.C.; Johnstone, J.F.; Kasischke, E.S.; Euskirchen, E.S.; Jones, J.B.; Jorgenson, M.T.; Kielland, K.; Kofinas, G.; Turetsky, M.R.; Yarie, J.; Lloyd, A.H.; Taylor, D.L.
Calibrating recruitment estimates for mourning doves from harvest age ratios
We examined results from the first national-scale effort to estimate mourning dove (Zenaida macroura) age ratios and developed a simple, efficient, and generalizable methodology for calibrating estimates. Our method predicted age classes of unknown-age wings based on backward projection of molt distributions from fall harvest collections to...Miller, David A.; Otis, David L.
Modeling the Effects of Mortality on Sea Otter Populations
Conservation and management of sea otters can benefit from managing the magnitude and sex composition of human related mortality, including harvesting within sustainable levels. Using age and sex-specific reproduction and survival rates from field studies, we created matrix population models representing sea otter populations with growth rates of...Bodkin, James L.; Ballachey, Brenda E.
The changing effects of Alaska’s boreal forests on the climate system
In the boreal forests of Alaska, recent changes in climate have influenced the exchange of trace gases, water, and energy between these forests and the atmosphere. These changes in the structure and function of boreal forests can then feed back to impact regional and global climates. In this manuscript, we examine the type and magnitude of the...Euskirchen, E.S.; McGuire, Anthony; Chapin, F.S.; Rupp, T.S.
Recovery of sediment characteristics in moraine, headwater streams of northern Minnesota after forest harvest
We investigated the recovery of sediment characteristics in four moraine, headwater streams in north-central Minnesota after forest harvest. We examined changes in fine sediment levels from 1997 (preharvest) to 2007 (10 years postharvest) at study plots with upland clear felling and riparian thinning, using canopy cover, proportion of...Vondracek, Bruce C.; Merten, Eric C.; Hemstad, Nathaniel A.; Kolka, Randall K.; Newman, Raymond M.; Verry, Elon S.
Abdominally implanted transmitters with percutaneous antennas affect the dive performance of Common Eiders
Implanted transmitters have become an important tool for studying the ecology of sea ducks, but their effects remain largely undocumented. To address this, we assessed how abdominally implanted transmitters with percutaneous antennas affect the vertical dive speeds, stroke frequencies, bottom time, and dive duration of captive Common Eiders (...Powell, Abby N.; Latty, Christopher J.; Hollmén, Tuula E.; Petersen, Margaret R.; Andrews, Russel D.