Post E.,Pennsylvania State University |
Bhatt U.S.,University of Alaska Fairbanks |
Bitz C.M.,University of Washington |
Brodie J.F.,University of British Columbia |
And 8 more authors.
Science | Year: 2013
After a decade with nine of the lowest arctic sea-ice minima on record, including the historically low minimum in 2012, we synthesize recent developments in the study of ecological responses to sea-ice decline. Sea-ice loss emerges as an important driver of marine and terrestrial ecological dynamics, influencing productivity, species interactions, population mixing, gene flow, and pathogen and disease transmission. Major challenges in the near future include assigning clearer attribution to sea ice as a primary driver of such dynamics, especially in terrestrial systems, and addressing pressures arising from human use of arctic coastal and near-shore areas as sea ice diminishes.
PubMed | University of Edinburgh, Simon Fraser University, University of Sheffield, University of California at Davis and 4 more.
Type: Journal Article | Journal: Nature genetics | Year: 2015
Three strikingly different alternative male mating morphs (aggressive independents, semicooperative satellites and female-mimic faeders) coexist as a balanced polymorphism in the ruff, Philomachus pugnax, a lek-breeding wading bird. Major differences in body size, ornamentation, and aggressive and mating behaviors are inherited as an autosomal polymorphism. We show that development into satellites and faeders is determined by a supergene consisting of divergent alternative, dominant and non-recombining haplotypes of an inversion on chromosome 11, which contains 125 predicted genes. Independents are homozygous for the ancestral sequence. One breakpoint of the inversion disrupts the essential CENP-N gene (encoding centromere protein N), and pedigree analysis confirms the lethality of homozygosity for the inversion. We describe new differences in behavior, testis size and steroid metabolism among morphs and identify polymorphic genes within the inversion that are likely to contribute to the differences among morphs in reproductive traits.
News Article | December 1, 2016
New research shows how changes in cooperation around natural resources can be more disruptive than declines in resource availability An interdisciplinary study released this month in the Proceedings of the National Academy of Sciences of the United States of America combines social and physical science in new ways, seeking to understand how changes in Arctic resource-sharing behaviors could affect highly cooperative communities and the households within. "It's a unique piece of science in that both process and results are an outcome of collaboration and interdisciplinary science -- communities, social scientists and physicists, ethnographic context and network math" says Shauna BurnSilver, assistant professor of environmental anthropology at the Arizona State University School of Human Evolution and Social Change and co-investigator of the study. "Combined, this joint approach yielded ways to think about change more than any discipline alone would have." Funded by the Bureau of Ocean Energy Management, the study focused on three indigenous Alaskan communities - two Iñupiaq and one Gwich'in Athabascan - whose livelihoods combine subsistence hunting and fishing and the cash economy. These households also depend on networks of social relationships to share food, labor and equipment in the face of high costs and resource variability. Three researchers -- BurnSilver, Professor of Resource Policy and Management Gary Kofinas (University of Alaska Fairbanks), and Natural Resources graduate student James Magdanz (at the time, a resource specialist for the Alaska Department of Fish and Game) -- worked in the field to gather data on the flow of food and resources via these community and family partnerships, exchanges, and sharing. They found that between 60-75% of all food flowing between households in these communities occurred based on social relationships rather than households working alone, findings that corroborate cultural narratives of Iñupiaq and Gwich'in as "people who share." BurnSilver then sent the data to social-ecological systems modeler Jacopo Baggio (previously with ASU's Center for Behavior, Institutions and the Environment, now with Utah State University, Logan) and two European physicists/mathematicians -- Alex Arenas and Manlio De Domenico (Rovira i Virgili University, Spain) -- who developed new methods for analyzing directed and weighted multiplex networks. A multiplex approach preserves key details on the relative importance of one type of relationship or species within a network, rather than making all ties equivalent. The resulting model was used to mimic the effects of potential social changes to that network structure versus climatic or ecological shocks that could reduce community connectedness and therefore resource abundance, directly and overall. "Social and ecological relationships are inherently complex so the ability to use a new methodology based on multiplex networks opens up really exciting perspectives," says De Domenico. "The integration of high quality social research and the latest methodological advances to analyze multiplex networks is how research boundaries can and will be pushed forward," Baggio adds. "Such integration sheds light on complex issues like interdependencies between social and ecological changes." Ultimately, the team was able to demonstrate that the loss of individual social relationships, such as sharing, or important households from these communities' social networks, could have even greater impacts on system connectivity than the loss of key animal species. As BurnSilver explains, the takeaway is meaningful, and not just for the inhabitants of Alaska. "Economic and climatic changes explored here reflect broader changes occurring globally - in places where social relationships remain the glue that holds people together and define the way that people experience and cope with change," she says. "Given all the attention to species losses in the Arctic due to climate change, we think this is an intriguing result," adds Magdanz. "People matter, and social relations matter." To access the abstract and a PDF of the full study "Multiplex social ecological network analysis reveals how social changes affect community robustness more than resource depletion," visit: http://www. . Researchers and Current/Past Affiliations: Shauna BurnSilver School of Human Evolution and Social Change, Arizona State University Gary Kofinas School of Natural Resources and Extension and Institute of Arctic Biology, University of Alaska Fairbanks Jacopo Baggio Department of Environment and Society, Utah State University, Logan At Time of Study: ASU's Center for Behavior, Institutions and the Environment James Magdanz School of Natural Resources and Extension, University of Alaska Fairbanks At Time of Study: Alaska Department of Fish and Game
Nash S.H.,Institute of Arctic Biology |
Nash S.H.,University of Alaska Fairbanks |
Nash S.H.,U.S. National Cancer Institute |
Kristal A.R.,Fred Hutchinson Cancer Research Center |
And 5 more authors.
Journal of Nutrition | Year: 2014
Objectively measured biomarkers will help to resolve the controversial role of sugar intake in the etiology of obesity and related chronic diseases. We recently validated a dual-isotope model based on RBC carbon (δ13C) and nitrogen (δ15N) isotope ratios that explained a large percentage of the variation in self-reported sugar intake in a Yup'ik study population. Stable isotope ratios can easily be measured from many tissues, including RBCs, plasma, and hair; however, it is not known how is otopic models of sugar intake compare among these tissues. Here, we compared self-reported sugar intake with models based on RBCs, plasma, and hair δ13C and δ15N in Yup'ik people. We also evaluated associations of sugar intake with fasting plasma glucose d13C. Finally, we evaluated relations between δ13C and δ15N values in hair, plasma, RBCs, and fasting plasma glucose to allow comparison of isotope ratios across tissue types.Models using RBCs, plasma, or hair isotope ratios explained similar amounts of variance in total sugar, added sugar, and sugar-sweetened beverage intake (~53%, 48%, and 34%, respectively); however, the association with δ13C was strongest for models based on RBCs and hair. There were no associations with fasting plasma glucose δ13C (R2 = 0.03). The δ13C and δ15N values of RBCs, plasma, and hair showed strong, positive correlations; the slopes of these relations did not differ from 1. This study demonstrates that RBC, plasma, and hair isotope ratios predict sugar intake and provides data that will allow comparison of studies using different sample types. ©2014 American Society for Nutrition.
Stimmelmayr R.,University of Trinidad and Tobago |
Stimmelmayr R.,Institute of Arctic Biology |
Stefani L.M.,Santa Catarina State University |
Thrall M.A.,University of Trinidad and Tobago |
And 6 more authors.
Avian Diseases | Year: 2012
We report the first documented occurrence of an outbreak of trichomonosis in a free-ranging small flock of Eurasian collared doves (Streptopelia decaocto) and African collared dove hybrids (Streptopelia risoria) in the Caribbean. In total, 18 birds were examined, including six African collared dove × Eurasian collared dove hybrids and 12 Eurasian collared doves. The affected age class consisted of adults. Sex distribution was equal. With a flock population size of 200 birds, mortality rate for the outbreak was estimated at 1520. Living birds were weak, showing evidence of mucus-stained beaks and open-mouth breathing. Caseous ulcerative yellow lesions were restricted to the upper gastrointestinal tract, with the exception of one bird, which had lesions in the upper gastrointestinal tract and in the liver. Ninety-four percent (17/18) of the affected birds had multiple extensive lesions. Lesions located on the roof of the oral cavity extended in 33 (6/18) into the orbit and in 11 (2/18) into the braincase. Using wet-mount microscopy, we were able to confirm Trichomonas gallinae in 22 (4/18) of the sampled animals. Fifteen samples submitted for PCR analysis tested positive. Sequence analysis of the internal transcribed spacer 1 (ITS-1) region of the ribosomal RNA (rRNA) revealed two distinct genotypes of Trichomonas. One sequence had 100 identity to the prototype T. gallinae isolate, whereas the other sequences had 98100 identity to recently described Trichomonas-like parabasalid. On the basis of gross and histologic findings, along with the sequence results from the columbids in this report, it is likely that this Trichomonas-like parabasalid is pathogenic. © American Association of Avian Pathologists.
Nash S.H.,Institute of Arctic Biology |
Nash S.H.,University of Alaska Fairbanks |
Kristal A.R.,Fred Hutchinson Cancer Research Center |
Bersamin A.,Institute of Arctic Biology |
And 6 more authors.
Journal of Nutrition | Year: 2013
The carbon isotope ratio (δ13C) is elevated in corn- and cane sugar-based foods and has recently shown associations with sweetener intake in multiple U.S. populations. However, a high carbon isotope ratio is not specific to corn- and sugar canebased sweeteners, as other foods, including meats and fish, also have elevated δ13C. This study examines whether the inclusion of a second marker, the nitrogen isotope ratio (δ15N), can control for confounding dietary effects on d13C and improve the validity of isotopic markers of sweetener intake. The study participants are from the Yup'ik population of southwest Alaska and consume large and variable amounts of fish and marine mammals known to have elevated carbon and nitrogen isotope ratios. Sixty-eight participants completed 4 weekly 24-h recalls followed by a blood draw. RBC δ13C and dδ15N were used to predict sweetener intake, including total sugars, added sugars, and sugar-sweetened beverages. A model including both δ13C and δ15N explained more than 3 times as much of the variation in sweetener intake than did a model using only δ13C. Because carbon and nitrogen isotope ratios are simultaneously determined in a single, highthroughput analysis, this dual isotope marker provides a simple method to improve the validity of stable isotope markers of sweetener intake with no additional cost. We anticipate that this multi-isotope approach will have utility in any population where a stable isotope biomarker is elevated in several food groups and there are appropriate "covariate" isotopes to control for intake of foods not of research interest. © 2013 American Society for Nutrition.
Bleich V.C.,Sierra Nevada Bighorn Sheep Recovery Program |
Bleich V.C.,Idaho State University |
Bleich V.C.,University of Nevada, Reno |
Whiting J.C.,Brigham Young University - Idaho |
And 2 more authors.
Wildlife Research | Year: 2016
Context. Little is known about the consequences of sexual segregation (differential use of resources by the sexes outside of the mating season) for the conservation of large mammals. Roadways (i.e. the strip of land over which a road or route passes) are ubiquitous around the world, and are a major cause of wildlife mortality, as well as habitat loss and fragmentation. Many populations of bighorn sheep (Ovis canadensis) occur at low densities and in a metapopulation structure. Roadways could affect movements of males and females differentially, an outcome that has not been considered previously. Aims. We investigated the propensity of the sexes to cross a paved two-lane road and a single-lane, maintained dirt route and predicted that adult males, because of their life-history characteristics, would cross those roadways more often than females. Methods. We investigated movements of male and female bighorn sheep from 1986 to 1990. We used a fixed-wing aircraft with an H-antenna on each wing strut to locate individuals each week from October 1986 to December 1990. We estimated the degree of overlap among 50% core areas of use by males and females with the utilisation distribution overlap index (UDOI). Key results. We relocated male and female bighorn sheep on 948 occasions during sexual aggregation and on 1951 occasions during sexual segregation. More males than females were likely to cross both types of roadways during segregation, and the dirt route during aggregation. Propensity of males and females to cross roadways was strongly influenced by time of year (i.e. whether the period of sexual aggregation or sexual segregation). The lowest overlap in 50% core areas was between females and males during periods of segregation (UDOI = 0.1447). Conclusions. More males than females crossed Kelbaker Road and the unnamed dirt route during segregation, as well as the unnamed route during aggregation. Both of those features could affect males more than females, and could result in reductions in the use of habitat or increased mortality of bighorn sheep from vehicle collisions as a result of spatial segregation of the sexes. Implications. During environmental review, biologists should consider sexual segregation when assessing potential anthropogenic effects on movements of bighorn sheep. Biologists also should consider sexual segregation and how roadways, even lightly traveled routes, affect movements of male and female ungulates differently before manipulating habitat, translocating animals, or constructing or modifying roadways. © The authors 2016.
Sheriff M.J.,Institute of Arctic Biology |
Kenagy G.J.,University of Washington |
Richter M.,University of Alaska Fairbanks |
Richter M.,University of Alaska Anchorage |
And 6 more authors.
Proceedings of the Royal Society B: Biological Sciences | Year: 2011
Ecologists need an empirical understanding of physiological and behavioural adjustments that animals can make in response to seasonal and long-term variations in environmental conditions. Because many species experience trade-offs between timing and duration of one seasonal event versus another and because interacting species may also shift phenologies at different rates, it is possible that, in aggregate, phenological shifts could result in mismatches that disrupt ecological communities. We investigated the timing of seasonal events over 14 years in two Arctic ground squirrel populations living 20 km apart in Northern Alaska. At Atigun River, snow melt occurred 27 days earlier and snow cover began 17 days later than at Toolik Lake. This spatial differential was reflected in significant variation in the timing of most seasonal events in ground squirrels living at the two sites. Although reproductive males ended seasonal torpor on the same date at both sites, Atigun males emerged from hibernation 9 days earlier and entered hibernation 5 days later than Toolik males. Atigun females emerged and bred 13 days earlier and entered hibernation 9 days earlier than those at Toolik. We propose that this variation in phenology over a small spatial scale is likely generated by plasticity of physiological mechanisms that may also provide individuals the ability to respond to variation in environmental conditions over time. © 2010 The Royal Society.
Mosher B.P.,University of Alaska Fairbanks |
Taylor B.E.,University of Alaska Fairbanks |
Taylor B.E.,Institute of Arctic Biology |
Harris M.B.,University of Alaska Fairbanks |
Harris M.B.,Institute of Arctic Biology
Respiratory Physiology and Neurobiology | Year: 2014
Serotonergic dysfunction compromises ventilatory chemosensitivity and may enhance vulnerability to pathologies such as the Sudden Infant Death Syndrome (SIDS). We have shown raphé contributions to central chemosensitivity involving serotonin (5-HT)-and γ-aminobutyric acid (GABA)-mediated mechanisms. We tested the hypothesis that mild intermittent hypercapnia (IHc) induces respiratory plasticity, due in part to strengthening of GABA mechanisms. Rat pups were IHc-pretreated (eight consecutive cycles; 5min 5% CO2 - air, 10min air) or constant normocapnia-pretreated as a control, each day for 5 consecutive days beginning at P12. We subsequently assessed CO2 responsiveness using the in situ perfused brainstem preparation. Hypercapnic responses were determined with and without pharmacological manipulation. Results show IHc-pretreatment induces plasticity sufficient for responsiveness despite removal of otherwise critical ketanserin-sensitive mechanisms. Responsiveness following IHc-pretreatment was absent if ketanserin was combined with GABAergic antagonism, indicating that plasticity depends on GABAergic mechanisms. We propose that IHc-induced plasticity could reduce the severity of reflex dysfunctions underlying pathologies such as SIDS. © 2014 Elsevier B.V.