• Molecular evidence of epithelial cell damage caused by iqmik, an Alaska smokeless tobacco mixture

      Dwyer, Gaelen K.; Knall, Cindy; Ferrante, Andrea; McGill, Colin; Johnson, Rhonda; Dunlap, Kriya (2015-08)
      The percentage of Alaska Natives who use smokeless tobacco (SLT) is 4 times that of non-Native Alaskans and 45 times higher for Alaska Native women than non-Native women. The use of SLT is concentrated in Southwest Alaska where 32% of all adult Alaska Natives use SLT. Out of those users, 35% use only iqmik, a unique form of SLT in Alaska, which is a combination of tobacco leaf mixed with Phellinus igniarius (punk fungus). There is little evidence of the pathological effects of iqmik to assist in the development of an evidenced-based intervention regarding the harmful effects of iqmik. The current lack of evidence reinforces a belief that iqmik is less harmful than other tobacco alternatives. The overall objective of this thesis is to elucidate the effect of iqmik and iqmik-mediated metal exposure on oxidative stress and nuclear factor- κB (NF-κB) induced inflammation in human gingival epithelial cells. The central hypothesis of this thesis is that cadmium (Cd), cobalt (Co) and nickel (Ni) accumulate in human gingival epithelial cells from iqmik treatments, inducing oxidative stress and promoting an intracellular environment that alters NF-κB proinflammatory signaling targets. Our findings indicate that iqmik is a greater source of heavy metals, such as Cd, Co and Ni, than air-cured tobacco leaf. Human gingival epithelial cells accumulate more Cd, Co and Ni from the punk ash component of iqmik than from the air-cured tobacco. These metals have the capacity to accumulate in cells from iqmik treatments and generate and propagate the production of endogenous reactive oxygen species (ROS), which activates NF-κB significantly altering its signaling targets, more so than tobacco alone. The results of this thesis identify iqmik as a unique health hazard compared to other tobacco products and enhances our understanding of how iqmik may contribute to oral pathologies.
    • Molecular evolution of martens (genus Martes)

      Stone, Karen Denise (2000-08)
      Molecular studies provide the opportunity to re-evaluate and further investigate hypotheses such as those related to phylogenetic relationships, inter- and intra-continental colonizations, population differentiation, and the dynamics of hybrid zones. Three sets of molecular markers, nuclear and mitochondrial, were used to examine phylogenetic relationships among species within a holarctically distributed genus (Martes), and intraspecific diversification and population differentiation within American marten (Martes americana). In American marten, two morphological groups ('americana' and 'caurina') have been recognized, though the level of distinctiveness between them has been debated. My data supported the fossil record's indication that early radiations gave rise to two subgenera of the genus Martes (Pekania and Charronia) and that a more recent, possibly rapid, radiation gave rise to species of the third subgenus (Martes). Two colonizations of North America are evident, one by members of the subgenus Pekania, and another by the subgenus Martes. However, contrary to hypotheses based on morphological evidence, the 'americana' and 'caurina' subspecies groups of Martes americana represent only one colonization. Cytochrome b data were consistent with the recognition of these as monophyletic clades; however, aldolase C sequences and microsatellite data indicated that these generaly parapatric groups interbreed in at least one region of limited geographic overlap. These clades probably were isolated during the late Pleistocene in eastern and western refugia, but geographic separation apparently has not led to reproductive isolation. My data also indicated two colonization events for the Pacific Northwest by American martens (one by each clade). Due to patterns of genetic variation, I hypothesize that the 'caurina' clade spread along the North Pacific Coast, including southeastern Alaska, earlier than the 'americana' clade, and that these clades have now formed a zone of secondary contact on Kuiu Island in southeastern Alaska. Microsatellite data revealed population differentiation among many island populations in the Pacific Northwest, but possible gene flow among several near-shore island and mainland populations was suggested. Analyses of genetic and geographic distances suggested that colonization history had a strong effect on present day population structure and that oceanic straits and possibly other physiographic features posed significant barriers to gene flow.
    • Molecular phylogenetics of arvicoline rodents

      Conroy, Christopher John; Cook, Joseph A. (1998)
      The impetus for this dissertation was an interest in geographic variation in Microtus longicaudus with a particular focus on populations in the Alexander Archipelago of southeastern Alaska. To establish a framework for interpreting intraspecific variation in M. longicaudus, I examined the phylogenetics of 28 species of the genus Microtus, including all North American species (Chapters 2 and 4). That study, which corroborates a rapid pulse of diversification noted in the fossil record, necessitated a deeper phylogenetic perspective. Thus, a third objective of the dissertation was to investigate relationships among genera of arvicolines within the framework of other murid rodents. I examined variation in the mitochondrial cytochrome b and ND4 genes using maximum parsimony, distance, and maximum likelihood phylogenetic analyses. Relationships at several taxonomic levels appear intractable due to rapid accumulation and survival of genetic lineages. These rapid radiations were found among species, genera, and possibly subfamilies; however, strong support at these levels for other taxa (e.g., the monophyly of Microtus) suggests these genes have strong phylogenetic signal. Many of the well-supported sister species pairs within Microtus (Chapters 2 and 4) had been previously identified based on morphologic or allozyme work (e.g., M. pennsylvanicus and M. montanus, M. pinetorum and M. quasiater). The sequence data supported a clade of taiga dwelling species in North America and a clade of eastern and central Asian species. The southernmost arvicoline species of Mexico and Guatemala, though previously suggested to be derived from a single ancient invasion, did not appear to be either ancient or monophyletic. Within M. longicaudus, a large east-west phylogeographic break was detected that is equivalent in genetic distance to other sister species pairs in the genus. This break may indicate mid to late-Pleistocene differentiation (Chapter 3) within the genus. At higher latitudes, populations of M. longicaudus exhibited evidence of recent range expansion including absence of correlation between geographic and genetic structure; and pairwise mismatches among DNA sequences with a single peak and few differences.
    • Molecular Population Genetics And Systematics Of Alaska Brown Bear (Ursus Arctos L.)

      Talbot, Sandra Looman; Follmann, Erich (2006)
      Complete nucleotide sequences of the mitochondrial cytochrome b, tRNAproline and tRNA threonine genes of the eight extant species of ursids, as well as 166 brown bears (Ursus arctos L.) from 10 geographic regions of Alaska and elsewhere, are used to generate hypotheses about phylogenetic relationships among ursids and phylogeographic relationships among brown bears. Additional data were obtained from mitochondrial DNA control region from over 200 brown bears among 14 populations in Alaska, to assess structuring among brown bears. Phylogenetic analyses indicate the giant panda (Ailuropoda melanoleuca) and spectacled bear (Tremarctos ornata) represent basal extant taxa. Ursines, including the sun bear (Helarctos malayanus), sloth bear (Melursus ursinus), Asiatic and American black bears (Ursus thibetanus and U. americanus), brown bear, and polar bear (U. maritimus) apparently experienced rapid radiation during the mid-Pliocene to early Pleistocene. The two black bears appear to be sister taxa; brown and polar bear are the most recently derived of the ursines. Polar bears apparently arose during the Pleistocene from within a clade of brown bears ancestral to populations currently inhabiting islands of the Alexander Archipelago of southeastern Alaska. Thus, brown bears are paraphyletic with respect to polar bears. Parsimony and distance analyses suggest two distinct clades of mtDNA: one (Clade I) composed only of Alexander Archipelago bears, and the other clade comprised of bears inhabiting all other regions of Alaska (Clade II). This latter clade represents bears inhabiting eastern (Clade IIa) and western (Clade IIb) Alaska. Mismatch analysis uncovered a pattern suggestive of recent expansion among some populations comprising Clade IIb. Over 90% of populations in Alaska were significantly differentiated as measured by variance in haplotype frequencies, suggesting limited contemporary female-mediated gene flow and/or shifts in gene frequency through genetic drift. The degree of population genetic differentiation revealed using mtDNA, as well as limited information from comparisons of multilocus microsatellite genotypes from bears representing four Alaska populations, suggests many Alaskan populations are evolving independently. Analyses of molecular variance gave little support for currently accepted subspecies hypotheses. This research has provided new perspectives on processes that drive population structure of brown bears of Alaska and worldwide.
    • Molecular systematics and biogeography of long-tailed shrews (Insectivora: Sorex) and northern flying squirrels (Rodentia: Glaucomys)

      Demboski, John Richard; Cook, Joseph A. (1999)
      Insight into phylogenetic and biogeographic relationships among several mammalian taxa in western North America was provided with DNA sequences of two mitochondrial genes (cytochrome b and ND4). Members of two species complexes of long-tailed shrews (genus Sorex ) and northern flying squirrels (genus Glaucomys) were examined, and a common theme of responses to past climate change and glacial cycles was evident. Diversification events indicated by the DNA sequences provide new perspectives regarding the deep and shallow history of these taxa. Analysis of seven species of the Sorex cinereus complex (and related species) revealed two major clades within the complex, Northern and Southern. These generally corroborate proposed morphological relationships and correspond to broadly defined habitat affiliations (xeric and mesic), respectively. Within the Northern clade, amphiberingian species represented a monophyletic group suggesting Beringia was a center of endemism. Next, five species of the S. vagrans complex and related species were assessed. Significant molecular variation was revealed that does not correspond to morphological differences within the complex. Two major clades within S. monticolus were observed, a widespread Continental clade (Arizona to Alaska, including S. neomexicanus) and a restricted Coastal clade (Oregon to southeast Alaska, including S. bairdi and S. pacificus). A regional examination of genetic variation in the northern flying squirrel in southeast Alaska was also performed. Results suggested that southern islands in the Alexander Archipelago were the result of recent colonization (founder event). Finally, a comparative phylogeographic analysis of a reduced data set (S. monticolus), a molecular data set for the American Pine Marten, Martes americana, and other published molecular studies were used to reexamine the role of glacial refugia in the biogeography of the north Pacific coast. Previous ideas regarding purported refugia may be overstated and may be the result of limited geographic sampling. This thesis provides new perspectives on processes (e.g., post-glacial colonization) driving mammalian phylogenetic and biogeographic structuring in western North America.
    • Monitoring energy and nitrogen availability for Arctic caribou (Rangifer tarandus)

      VanSomeren, Lindsay L.; Barboza, Perry S.; Bret-Harte, M. Sydonia; Gustine, David D. (2014-12)
      Arctic caribou and reindeer (Rangifer tarandus) are an economically and ecologically important species. Rangifer populations are often affected by nutritional factors. Our ability to monitor nutrient supply to arctic ungulates is presently limited by a lack of techniques to consistently and easily measure availability of specific nutrients and which may disproportionately affect different segments of Rangifer populations. I refined and validated a method to measure availability of specific nutrients including nitrogen (N) and energy to caribou using purified fibrolytic enzymes and acid/pepsin to simulate digestion. I then used this method to measure how availability of nitrogen and energy was altered by anti-nutrients such as indigestible fiber and toxins. Digestible N contents in forages declined to almost zero by the end of the growing season, whereas digestible energy concentrations were still sufficient to meet basic maintenance requirements for caribou by the end of the growing season in shrub and forb forages. Shrubs contained the highest amounts of total N and energy, however this was reduced by fiber and toxins so that shrubs contained the lowest digestible N contents, especially for Betula nana. Graminoids were extremely low in digestible energy content, which may necessitate a high degree of selection among plant parts by herbivores. Dietary choice over long- and short-term periods may be assessed using non-invasive stable isotope techniques, nevertheless, the understanding of how isotopic signatures vary over spatial, temporal, and species-specific scales and how isotopic signatures are changed by digestive processes is limited. Monocot (graminoid) and dicot (browse and forb) forages both differed in values of 13C and 15N, however regional and seasonal shifts in 13C were larger than the differences among forage groups themselves. Forage isotopic signatures also changed after simulated digestive processes, yet this was only significant for species with very low (< 52.6 % N) or very high (> 36.6 % C) digestibilities. These studies suggest that nitrogen may be a limiting nutrient for caribou populations. Persistence of arctic caribou populations in a changing climate may depend, in part, upon continued access to calving grounds, the change in abundance of individual shrub species, and/or the ability of caribou to behaviorally and physiologically cope with increasing amounts of toxins in shrubs.
    • Monitoring small scale explosive activity as a precursor to periods of heightened volcanic unrest

      Worden, Anna K. (Anna Kristine); Dehn, Jonathan; Christensen, Douglas; Webley, Peter (2014-05)
      Volcanic activity can pose a threat to the public and infrastructure. This threat is mitigated by monitoring volcanoes and volcanic activity. In many places this can be hindered by remote location and high cost. Satellite remote sensing is a tool that can be used to safely monitor volcanic activity and aid in the mitigation of hazards and the implementation of hazard preparedness. Small scale explosive activity is often a precursor to periods of heightened volcanic activity. This activity is typified by distinct small explosions that eject hot material onto the flanks of a volcano and can be detected as thermal anomalies by satellite sensors. The aim of this study is to develop a monitoring tool to detect changes in the frequency of small explosions leading up to periods of activity with ash plumes and other volcanic activity. Development of this method was carried out on Stromboli Volcano in Italy, a very reliably eruptive volcano with a wide variety of other monitoring instrumentation collecting data. Once developed, the method was applied to three remote volcanoes in the North Pacific: (1) Chuginadak (Mt. Cleveland) and (2) Shishaldin in Alaska, USA; and (3) Karymsky Volcano in Kamchatka, Russia. The results produced at all four of these volcanoes showed distinct trends in activity, unique to each volcano, prior to periods of heightened eruptive activity. The method provides a baseline for the detection of precursory activity and these trends can be used on other volcanoes undergoing similar types and patterns of eruptive activity.
    • Moose (Alces alces) browse availability and use in response to post-fire succession on Kanuti National Wildlife Refuge, Alaska

      Julianus, Erin L.; McGuire, A. David; Nettleton Hollingsworth, Teresa; Kielland, Knut (2016-08)
      I examined post-fire moose habitat dynamics on Kanuti National Wildlife Refuge in interior Alaska with the objective of increasing understanding of local moose habitat characteristics. I estimated browse density, biomass, and summer browse use in a 2005 burn, 1990 burn, 1972 burn, and an unburned area. I revisited each site the following spring to estimate browse availability and removal during winter. In addition to evaluating browse production and use, I estimated proportional habitat use of varying-aged burns by 51 VHF-collared moose. I found that summer browse production and winter browse availability were highest in the 1990 and 2005 burns. I found that summer and winter browse use was highest in the 1990 burn. Collared moose generally avoided recently burned stands and demonstrated preference for >30 year old stands in both summer and winter. Moose demonstrated preference for unburned stands during calving. Although biomass production and availability were highest in 11 – 30 year old stands, disproportionate use of food resources in burns was evident. This disproportionate use of burns and food resources could be due to a variety of reasons including resource type, historic moose distribution patterns, and predation avoidance strategies.
    • Moose abundance estimation using finite population block kriging on Togiak National Wildlife Refuge, Alaska

      Frye, Graham G. (2016-12)
      Monitoring the size and demographic characteristics of animal populations is fundamental to the fields of wildlife ecology and wildlife management. A diverse suite of population monitoring methods have been developed and employed during the past century, but challenges in obtaining rigorous population estimates remain. I used simulation to address survey design issues for monitoring a moose population at Togiak National Wildlife Refuge in southwestern Alaska using finite population block kriging. In the first chapter, I compared the bias in the Geospatial Population Estimator (GSPE; which uses finite population block kriging to estimate animal abundance) between two survey unit configurations. After finding that substantial bias was induced through the use of the historic survey unit configuration, I concluded that the ’’standard” unit configuration was preferable because it allowed unbiased estimation. In the second chapter, I examined the effect of sampling intensity on performance of the GSPE. I concluded that bias and confidence interval coverage were unaffected by sampling intensity, whereas the coefficient of variation (CV) and root mean squared error (RMSE) decreased with increasing sampling intensity. In the final chapter, I examined the effect of spatial clustering by moose on model performance. Highly clustered moose distributions induced a small amount of positive bias, confidence interval coverage lower than the nominal rate, higher CV, and higher RMSE. Some of these issues were ameliorated by increasing sampling intensity, but if highly clustered distributions of moose are expected, then substantially greater sampling intensities than those examined here may be required.
    • A morphological and genetic investigation of the highest-latitude endemic passerine: McKay's bunting

      Maley, James Michael; Winker, Kevin; McCracken, Kevin; Powell, Abby; Olson, Link (2006-05)
      I used two different approaches to investigate different aspects of the highest latitude endemic passerine, McKay's Bunting (Plectrophenax hyperboreus). I tested whether or not the juvenal plumage of McKay' s Bunting is different from its closest relative, Snow Bunting (P. nivalis). Using light reflectance spectrophotometry to quantify visual differences, I found that McKay's and Snow buntings have significantly different juvenal plumages. This analysis supports their separation into two distinct species. Second, I investigated the genetic consequences of refugial isolation and the model of speciation that the genetic data fit. This species pair provides an excellent opportunity to investigate the genetic effects of speciation at high latitudes in a region known to be significantly impacted by Pleistocene climatic oscillations. Using a mitochondrial marker and anonymous nuclear markers, I found evidence for recent divergence and a very small founding population size of McKay's. After the founder event, there is evidence of a population expansion and a subsequent reduction of the McKay's population, probably as a result of rising sea levels and asymmetric hybridization into Snow Buntings postglacially colonizing Beringia. This recent, high latitude speciation event fits a model of founder effect peripatric speciation driven by a small founding population size and genetic drift.
    • A morphological and genetic review of the Pardosa groenlandica species complex (Araneae: Lycosidae)

      Slowik, Jozef; Sikes, Derek; Winker, Kevin; Cushing, Paula (2011-08)
      The Pardosa groenlandica species complex comprises seven recognized species, P. groenlandica (Thorell 1872), P. dromaea (Thorell 1877), P. tristis (Thorell 1877), P. prosaica Chamberlin and Ivie 1947, P. bucklei Kronestedt 1975, P. albomaculata Emerton 1885, and P. lowriei Kronestedt 1975. These species have overlapping distributions, creating sympatric occurrences with at least one other member of the complex. They can be found in Greenland, throughout Canada, and occur in the United States from the Rocky Mountains to the Pacific coast, through Alaska, and as far as eastern Siberia. These species' genitalia, which bear the primary diagnostic characters, are very similar and show large amounts of within-species and within-population variation. Because of this, they have seen various levels of taxonomic splitting and lumping from one species to the presently recognized seven. I evaluated the utility of the existing morphological diagnostic characters which, if geography is ignored, successfully diagnose only four species (P. albomaculata, P. lowriei, and P. bucklei, with the remaining species synonymized under P. groenlandica). Additionally, I sequenced five genes, two mitochondria) (COI & NDI), and three nuclear genes (ITS 1, 5.8S, and ITS2) of 144 specimens, to help clarify the taxonomy of the species complex. All seven species showed some level of polyphyly or paraphyly in their gene trees. A population genetics analysis of P. groenlandica and P. tristis from Colorado populations failed to find molecular divergence between the populations, raising questions about P. groenlandica occurring in Colorado, and/or the validity of P. tristis. These results question the value of using this genetic dataset to test species delineated using traditional taxonomic methods in the groenlandica species complex of the genus Pardosa. Reconciliation is likely only when genetic markers are studied that match the timing and rate of the observed phenotypic changes.
    • A mosquito (Diptera: Culicidae) model for the transmission of tularemia

      Triebenbach, Alison N. (2009-08)
      Tularemia is a plague-like disease caused by the bacterium Francisella tularensis. In Scandinavian countries tularemia transmission is clinically attributed to mosquitoes. To examine the transmission of tularemia by mosquitoes I exposed Aedes aegypti and Anopheles gambiae larvae to F. tularensis and tested all life stages for bacterial DNA using real-time polymerase chain reaction (rtPCR). I fed adult A. aegypti and An. gambiae a blood meal containing F. novicida and tested for DNA 24, 48 and 72 hours after feeding. Seventy-two hours after the F. novicida blood meal I allowed A. aegypti and An. gambiae to feed on a mouse. My results indicate that 1. Aedes aegypti and An. gambiae larvae ingest F. tularensis but eliminate it from their system before maturing to adults and, 2. F. novicida DNA is present in adults 72 hours after feeding, and 3. mice remained healthy after multiple mosquitoes feeding on them. Although this implies F. tularensis is not spread by A. aegypti and An. gambiae, it exemplifies the need to investigate other subspecies of F. tularensis and other species of mosquito to eliminate species dependence.
    • Motivations and drivers of trapper catch per unit effort in Alaska

      Dorendorf, Ross R.; Prugh, Laura; Kielland, Knut; Brainerd, Scott; Fix, Peter (2015-08)
      Indices of abundance based on harvest alone have long been used to track furbearer populations. However, abundance indices based on harvest alone do not account for variation in trapping effort. To my knowledge, adjusting harvest-based furbearer abundance indices to account for effort has not been previously examined in Alaska. Understanding how effort varies among trappers, and how social issues and external factors such as human conflict and fur prices affect effort, can give a clearer understanding of why trapping effort changes. A trapper's motivations may determine how strongly various external factors and social issues influence trapping effort. I sent a questionnaire to trappers of interior Alaska and used nine years of statewide data from the Alaska Trapper Questionnaire (distributed annually by the Alaska Department of Fish and Game) to address these issues. Across five regions from 2004-2013, I found that total fur harvest increased with per-capita trapper effort (R² = 0.125, p = 0.02). Variation in average winter temperature across game management regions explained 42% of variation in trapping effort, but annual variation in temperature, snow depth, fur prices, and fuel prices did not affect effort. Corresponding to these statewide findings, surveys of trappers in interior Alaska indicated that economic gain was not a strong motivation to trap, a finding that differs from previous studies. The most important social issues and external factors affecting trapping effort were access to land and the perceived abundance of furbearer populations respectively. To determine the motivations of interior Alaskan trappers, I used a k-means cluster analysis that identified four groups of trappers: management (17% of trappers), recreational (39%), subsistence (18%), and solitary (26%). Each group is represented by its strongest motivation for trapping. To improve the use of harvest as an index of furbearer abundance, I recommend accounting for trapping effort by calculating catch-per-unit-effort (CPUE), a metric commonly used in fisheries. I further recommend that resource managers should focus their efforts on reducing human conflicts while maximizing the non-monetary benefits of trapping. Resource managers should take advantage of questionnaires to help understand the fluctuations in furbearer populations and understand the motivations of trappers.
    • Mouse circadian plasma leptin and active ghrelin rhythms under ad libitum and scheduled feeding

      Wan, Haiting (2007-08)
      Light is the strongest timing cue for the circadian system, but non-photic cues can also entrain the master circadian clock, i.e., suprachiasmatic nuclei (SCN). In one of our mouse line (ENTR), all mice entrain to scheduled feeding, while in another (NON-ENTR) only 4 % entrain. In order to explore key physiological pathways involved in that process, I quantified the circadian rhythms of plasma leptin and active ghrelin of these two lines of mice under a 12:12 hour light-dark cycle with ad libitum feeding and six hours of food availability during the light period. Plasma active ghrelin induced opposite circadian rhythms compared to leptin, which were most pronounced under scheduled feeding when leptin was highest during and right after the food availability period; active ghrelin was highest at night when food was not available. Compared to ad libitum feeding, the overall concentration of leptin decreased and active ghrelin concentration increased significantly under scheduled feeding. The plasma active ghrelin circadian rhythms of ENTR mice were more robust with higher amplitude rhythms than the NON-ENTR mice under ad libitum feeding and scheduled feeding. I hypothesize that the high amplitude plasma active ghrelin circadian rhythm provides a signal for the ENTR mice to entrain to scheduled feeding
    • Movement and migration ecology of Alaskan golden eagles

      Eisaguirre, Joseph Michael; Breed, Greg; Booms, Travis; Doak, Pat; Kielland, Knut; McIntyre, Carol (2020-05)
      Golden eagles Aquila chrysaetos are distributed across the Holarctic; however, in Alaska and other northern areas, many are long-distance migrants. Being soaring birds, golden eagles can use weather and features of the energy landscape to offset the energetic costs of movement and migration. In this dissertation, I investigate how dynamic energy landscapes, in addition to other habitat and anthropogenic features, affect the movement and migration ecology of Alaskan golden eagles; in most cases I did such by developing and applying new, biologically-appropriate statistical methods. First, I identified a single, discrete navigation decision that each eagle made during migration and determined which weather variables are primary factors in driving that decision. I found that wind was the primary correlate to the decision, consistent with eagles likely avoiding poor migration conditions and choosing routes based on favorable wind conditions. Second, I investigated how different forms of flight subsidies, which were orographic uplift, thermal uplift, and wind support, drove behavioral budgets and migratory pacing of eagles. I found a consistent daily rhythm in eagle behavior and migratory pace, seemingly driven by daily development of thermal uplift, with extended periods of slower-paced movements, consistent with periods of opportunistic foraging. Third, I investigated the effects of anthropogenic linear features, such as roads and railroads, on eagle movement during migration. I found that eagles selected for roads during spring migration and were more likely to be near roads when making slower-paced movements, which would be most frequent during times when limited thermal uplift is available. Lastly, I compared how floaters (breeding-age, non-territorial individuals) and territorial eagles used space and selected for resources, specifically interested in how their movements and space use might overlap. I found that floater space use was much more expansive, yet they only selected for habitats and resources slightly differently than territorial eagles. I also found their home ranges overlap substantially, suggesting that floaters play a key role in the population ecology of migratory golden eagles in Alaska.
    • Multi-decadal variability of Atlantic water heat transports as seen in the community climate systems model version 3.0

      Sterling, Kara (2006-05)
      Changes in oceanic heat transports from the North Atlantic to the Arctic, via Atlantic Water (AW), can have widespread impacts upon Arctic climate. Using a multi-century control simulation from the National Center for Atmospheric Research (NCAR) Community Climate Systems Model version 3.0 (CCSM3), the natural multi-decadal variability (MDV) of AW is characterized. Calculations of AW volume fluxes and heat transports into the Arctic are analyzed for the Svinøy transect, Fram Strait, and Barents Sea Opening (BSO), and compared with observations. Warm and cold phases of AW are examined through composite analysis, and quantified with respect to their effects on Arctic climate. The model captures several key features of AW, such as the overall circulation and depth of the AW core, but over-estimates AW temperatures by about 1 ⁰C. AW heat anomalies can be tracked from the Svinøy transect to the Arctic interior with a timescale of 13 years, which is comparable to observations. Composites reveal a deepening (shoaling) of the AW core during warm (cold) periods. Warm (cold) periods are also characterized by greater AW transports through the BSO (Fram Strait), implying the existence of an internal ocean feedback mechanism that helps to regulate oscillations of AW between warm/cold periods.
    • A multi-sensor approach to determining volcanic plume heights in the North Pacific

      Ekstrand, Angela L. (2012-05)
      During a volcanic eruption, accurate height information is necessary to forecast a volcanic plume's trajectory with volcanic ash transport and dispersion (VATD) models. Recent events in the North Pacific (NOPAC) displayed significant discrepancies between different methods of plume height determination. This thesis describes two studies that attempted to resolve this discrepancy, and identify the most accurate method for plume height determination. The first study considered the 2009 eruption of Redoubt Volcano. This study found that the basic satellite temperature method, in which satellite thermal infrared temperatures are compared to temperature-altitude profiles, vastly underestimates volcanic plume height due to decreased optical depth of plumes soon after eruption. This study also found that the Multi-angle Imaging SpectroRadiometer (MISR) produced very accurate plume heights, even for optically thin plumes. The second study investigated the application of MISR data to multiple eruptions in the NOPAC: Augustine Volcano in 2006, Okmok, Cleveland, and Kasatochi volcanoes in 2008, and Redoubt and Sarychev Peak volcanoes in 2009. This study found that MISR data analysis retrieves accurate plume heights regardless of grain size, altitude, or water content. Exceptions include plumes of low optical depth over bright backgrounds. MISR is also capable of identifying ash clouds by aerosol type.
    • Multi-sensor techniques for the measurement of post eruptive volcanic deformation and depositional features

      McAlpin, David B.; Meyer, Franz J.; Begét, James; Webley, Peter W.; Dehn, Jonathan (2019-08)
      Remote sensing of volcanic activity is an increasingly important tool for scientific investigation, hazard mitigation, and geophysical analysis. These studies were conducted to determine how combining remote sensing data in a multi-sensor analysis can improve our understanding of volcanic activity, depositional behavior, and the evolutionary history of past eruptive episodes. In a series of three studies, (1) optical photogrammetry and synthetic aperture radar are combined to determine volumes of lahars and lava dome growth at Redoubt Volcano, Alaska; (2) applied data from multiple synthetic aperture radar platforms are combined to model long-term deposition of pyroclastic flow deposits, including past deposits underlying current, observable pyroclastic flow deposits at Augustine Volcano, Alaska; and finally (3) combined, low-spatial-resolution thermal data from Advanced Very High Resolution Radiometer sensors are combined with high resolution digital elevation models derived from the microwave TanDEM-X mission, to increase the accuracy of eruption profiles and effusion rates at Tolbachik Volcano on the Kamchatka Peninsula, Russian Far East. As a result of this study, the very diverse capabilities of multiple remote sensing instruments were combined to improve the understanding of volcanic processes at three separate locations with recent eruptive activity, and to develop new methods of measurement and estimation by merging the capabilities of optical, thermal, and microwave observations. With the multi-sensor frameworks developed in this study now in place, future efforts should focus on increasing the diversity of sensor types in joint analyses, with the objective of obtaining better solutions to geophysical questions.
    • Multiple imputation of missing multivariate atmospheric chemistry time series data from Denali National Park

      Charoonsophonsak, Chanachai; Goddard, Scott; Barry, Ronald; McIntyre, Julie; Short, Margaret (2020-05)
      This paper explores a technique where we impute missing values for an incomplete dataset via multiple imputation. Incomplete data is one of the most common issues in data analysis and often occurs when measuring chemical and environmental data. The dataset that we used in the model consists of 26 atmospheric particulates or elements that were measured semiweekly in Denali National Park from 1988 to 2015. The collection days were alternating between three and four days apart from 3/2/88 - 9/30/00 and being consistently collected every three days apart from 10/3/00 - 12/29/15. For this reason, the data were initially partitioned into two in case the separation between collection days would have an impact. With further analysis, we concluded that the misalignments between the two datasets had very little or no impact on our analysis and therefore combined the two. After running five Markov chains of 1000 iterations we concluded that the model stayed consistent between the five chains. We found out that in order to get a better understanding of how well the imputed values did, more exploratory analysis on the imputed datasets would be required.
    • Multistate Ornstein-Uhlenbeck space use model reveals sex-specific partitioning of the energy landscape in a soaring bird

      Eisaguirre, Joseph M.; Goddard, Scott; Barry, Ron; McIntyre, Julie; Short, Margaret (2019-12)
      Understanding animals’ home range dynamics is a frequent motivating question in movement ecology. Descriptive techniques are often applied, but these methods lack predictive ability and cannot capture effects of dynamic environmental patterns, such as weather and features of the energy landscape. Here, we develop a practical approach for statistical inference into the behavioral mechanisms underlying how habitat and the energy landscape shape animal home ranges. We validated this approach by conducting a simulation study, and applied it to a sample of 12 golden eagles Aquila chrysaetos tracked with satellite telemetry. We demonstrate that readily available software can be used to fit a multistate Ornstein-Uhlenbeck space use model to make hierarchical inference of habitat selection parameters and home range dynamics. Additionally, the underlying mathematical properties of the model allow straightforward computation of predicted space use distributions, permitting estimation of home range size and visualization of space use patterns under varying conditions. The application to golden eagles revealed effects of habitat variables that align with eagle biology. Further, we found that males and females partition their home ranges dynamically based on uplift. Specifically, changes in wind and the angle of the sun seemed to be drivers of differential space use between sexes, in particular during late breeding season when both are foraging across large parts of their home range to support nestling growth.