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Wildfire is ubiquitous to interior Alaska and is the primary large-scale disturbance regime affecting thawing permafrost and ecosystem processes in boreal forests. Since surface and near surface hydrology is strongly affected by permafrost occurrence, and wildfire can consume insulating organic layers that partially control the thickness of the active layer overlying permafrost, changes in the active layer thickness following fire may mark a distinct change in surface hydrology. In this study, we examined surface area dynamics of lakes following wildfire in four regions of Interior Alaska during a 25-year period from 1984 - 2009. We compared the surface water dynamics of lakes in burned areas relative to lakes in...
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Understanding processes and mechanisms resulting in observed ecological patterns is critical information for biologists charged with effectively managing and conserving wildlife populations. In many areas across North America woodland caribou (Rangifer tarandus caribou Gmelin) populations are declining, as are caribou and reindeer populations globally. Why these declines are occurring is a key research question of biologists and managers. I investigated factors influencing recruitment of mountain-dwelling woodland caribou using long-term time series from ten herds (populations) in the Yukon Territory, Canada (Yukon). Recruitment was indexed by the calf:cow ratio observed during the fall breeding season using data...
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Survey data for trumpeter swans were collected throughout Alaska since 1968, but due to design difficulties and past analytical limitations, previous analyses were limited to simple summary statistics. The main purpose of my work was to rigorously analyze these data using advanced methods and determine rates of population change, the effects of environmental change on habitat use, and the influences of habitat features on habitat occupancy. I estimated that the adult population grew at a rate of 5.9% (95% credible interval = 5.2% to 6.6%) and production of cygnets increased at 5.3% (95% credible interval = 2.2% to 8.0%) annually. I also found evidence that variation in occupancy was positively related to average...
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"Biological, climatological, and hydrological data were collected from Clear Creek-Hogatza River from 1995 to 1997. A counting tower and partial weir were constructed to estimate chum salmon (Oncorhynchus keta). Partial hour counts were tested to see if they adequately estimated full hour counts. Chi-square tests indicated all estimates based on partial hour counts differed significantly from hour counts. ANOVA indicated no partial hour count differed significantly from the hour counts. Relative error analysis showed counts greater than 20 minutes produced unbiased estimates of hour counts. The three year estimated average was 96,932 salmon with the average peak occurring on 3 July. A 1:1 sex ratio existed with...
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Recent declines in the number of sockeye salmon Onchorynchus nerka returning to Lake Clark, Alaska have caused economic hardship in the region and raised resource concerns among local subsistence users and Federal managers. A lack of information regarding the distribution of spawning habitats in the glacially turbid Lake Clark watershed instigated this research. Radio telemetry was used to 1) determine the in-lake movement patterns of adult sockeye salmon and 2) identify sockeye salmon spawning locations. Sockeye salmon were radio tagged at they entered Lake Clark and tracked to spawning locations. After entering Lake Clark, sockeye salmon usually migrated to a region of the lake that was within 15 km of their spawning...
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Chemical and isotopic analyses of pore water from permafrost cores taken from the dry lake bed of ancient Lake Atna in the Copper River Basin and from an upland loess deposit northeast of Fairbanks, Alaska reveal information about the local past environments not available by other means. Thawed core samples from both sites were analyzed for δ 18 O and δD values using an isotope ratio mass spectrometer. Water content was determined as well, and subsamples of the cores were analyzed for nitrogen and carbon content. Water extracts of the core samples were analyzed for cations (Ca, Mg, K and Fe), as well as pH, electrical conductivity, and bicarbonate. Magnetic susceptibility was determined on samples from the Fairbanks...
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General Circulation Models suggest a future climate of warmer and possibly drier summers in the boreal forest region, which could change fire regimes in high latitudes. Thunderstorm development is a dominant factor in the continental boreal forest fire regime, through its influence as a fire starting mechanism. Global Climate Change research has identified the land-atmosphere interface as a vital area of a needed research in order to improve our predictions of climate change. This dissertation has focused on the development of thunderstorms and lightning strike activity in a boreal forest region in Interior Alaska and on how the underlying surface can influence their development. I have examined the distributions...
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Contents: Introduction -- The Northway Whitefish Project -- Theoretical approach -- Thesis structure -- Background and methods -- Gender, knowledge, and environmental change related to humpback whitefish (Coregonus pidschian) in Interior Alaska -- Time, expertise, and more time : four heuristics for developing trust between researchers and residents in participatory studies of subsistence resources -- Generating knowledge and questions about humpback whitefish (Coregonus pidschian) in Interior Alaska though connecting local and scientific experts -- Synthesis and discussion -- References -- Appendix 1. Northway guide to researchers -- Appendix 2. Interview guides used during this study -- Appendix 3. Release forms...
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Using a mark-recapture design, an epidemiological investigation of Hepatitis B was performed on four colonies of Spermophylus parryi. Animals were trapped, marked and bled. Serum samples were screened for Hepatitis B markers. Program MARK was used to estimate survival rates. Prevalence rates ranged over 55% and 1999 rates were 10% higher than 1998. Vertical transmission of the virus was not observed and juveniles were unaffected by the mother's hepatitis status. Immigrants had lower prevalence rates than residents and incidence rates accelerated throughout the study. Survival was highest during the over-winter period and adult rates were lower in 1999. Recovered animals had different survival rates than other animals...
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We isolated luminous bacteria from drying chum salmon, Oncorhynchus keta, reported by Alaska native fishermen to be 'glowing in the dark.' The salmon were harvested for subsistence use from the Yukon River, Alaska. We identified our luminous bacterial isolates as Photobacterium phosphoreum based on nutritional versatility, and 16S rDNA and luxA gene sequences. P. phosphoreum has previously only been isolated from the marine environment. We tested whether our strains, isolated from fish harvested in freshwater, represent cold-adapted, freshwater-tolerant strains of P. phosphoreum. We also analyzed lux operon composition and organization, and examined the 5' promoter region of the lux operon for shared genes and regulatory...
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"Habitat selection by calving caribou (Rangifer tarandus granti) of the Central Arctic Herd, Alaska, was assessed in relation to distance from roads, vegetation type, relative plant biomass (NDVI; Normalized Difference Vegetation Index), accumulation of plant biomass during early lactation (NDVIrate), snow cover, and terrain ruggedness. From 183 calving sites of 96 radio collared- females, 1980-95, calving distribution was estimated in reference (no development) and treatment (oilfields present) zones east and west of the Sagavanirktok River, respectively. In the reference zone, caribou regularly selected wet-graminoid vegetation, above-median NDVIrate, and non-rugged terrain; concentrated calving remained in habitats...
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Hatcheries play an important role in the enhancement of Pacific salmon (genus Oncorhynchus) as a resource, but genetic and phenotypic divergence trom wild populations may occur as a result of founder effects, genetic drift and/or domestication. In this study, agonistic behavior, ability to establish dominance, and morphology were compared among juveniles of chinook salmon (Oncorhynchus tshawytscha) that have experienced five generations of hatchery ranching culture, juveniles derived trom the wild founding stock, and second generation hybrids of the two lines. The parent generation of all lines was cultured in the same hatchery environment as the juveniles tested. Behavioral observations were conducted in replicate...
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Gynodioecy, the co-occurrence of females and hermaphrodites, is considered an intermediate step in the evolution of separate sexes in flowering plants. Highly variable female frequencies among populations suggest structuring of sex determining genes and differences in the relative fitness of females and hermaphrodites as seed parents. I investigated spatial variability in sex ratio and the effects of inbreeding on offspring quality in Silene acaulis. Female frequencies varied among populations from 0.32 to 0.69, and most were at temporal equilibrium. Females were significantly clumped within two of six populations. Females produced from 4 to 27 times as many fruits as hermaphrodites. Self-pollination of hermaphrodites...
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A spruce bark beetle (Dendroctonus rufipennis) epidemic in the Copper Basin of Alaska beginning in the late 1980's has infested over 200,000 ha of white spruce forests in the region. The impact of spruce beetle-induced habitat changes on the northern red-backed vole (Clethrionomys rutilus) was investigated using mark/recapture techniques for 2 field seasons. Vole abundance and recruitment was significantly greater on low versus heavily infested sites but a large vole survival response was lacking. Vole food resources and protective vegetative cover did not vary substantially in areas with different levels of spruce mortality. Male movement distances were influenced by sex ratio, and females appeared to respond to...
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Chum salmon (Oncorhynchus keta ) are important for subsistence and commercial harvest in Alaska. Variability of returns to western Alaskan drainages that caused economic hardship for stakeholders has led to speculation about reasons, which may include both anthropogenic and environmental causes in the marine environment. Mixed stock analysis (MSA) compares genetic information from an individual caught at sea to a reference baseline of genotypes to assign it to its population of origin. Application of genetic baselines requires several complex steps that can introduce bias. The bias may reduce the accuracy of MSA and result in overly-optimistic evaluations of baselines. Moreover, some applications that minimize bias...
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Winter browsing of birch leads to chemical changes in leaves of the following growing season, potentially generating differences in the quality of leachates derived from leaf litter and in leachate use by stream microorganisms. The effects of moose browsing were tested on leachates from leaves collected from browsed and unbrowsed trees and inoculated with microbial communities. Respiration and bacterial abundance were used to assess qualitative differences in leachates. Microbes cultured in leachates derived from leaves of browsed trees had significantly higher rates of oxygen uptake. There were no significant differences in bacterial abundance between treatments. The basis for the qualitative difference in leachates...
map background search result map search result map Winter vertebrate browsing of birch: effects on the use of leaf litter leachates by stream microorganisms Hepatitis B in Arctic ground squirrels (Spermophylus parryi): epidemiology and population biology Linking local knowledge and fisheries science : the case with humpback whitefish (Coregonus pidschian) in Interior Alaska The effects of climate change on the population dynamics of trumpeter swans Spatio-temporal recruitment dynamics of mountain-dwelling caribou in the Yukon Territory, Canada Characterization of permafrost development by isotopic and chemical analysis of soil cores taken from the copper river basin and an upland loess deposit in interior Alaska Breeding ecology and fasting tolerance of scaup and other ducks in the boreal forest of Alaska Habitat selection by calving caribou of the Central Arctic Herd, 1980-95 The ecological genetics of gynodioecy in Silene acaulis L. (Caryophyllaceae) : spatial sex structure and inbreeding depression Response of northern red-backed vole (Clethrionomys rutilus) populations to a major spruce beetle infestation in the Copper River Basin, Alaska Abundance and timing of summer run Chum salmon (Onchorhynchus keta) and water quality in Clear Creek-Hogatza River, northwestern Alaska Isolation and characterization of photobacterium phosphoreum from migrating Alaskan salmon Variation of agonistic behavior and morphology among juvenile chinook salmon (Oncorhynchus tshawytscha) of hatchery, wild, and hybrid origin under common rearing conditions Surface water dynamics of shallow lakes following wildfire in Boreal Alaska Yukon Water Availability Analysis: An Assessment of the Potential Impacts of Climate Change on the Balance between Precipitation and Potential Evapotranspiration in the Yukon, Canada The migration and spawning distribution of sockeye salmon within Lake Clark, Alaska Socio-ecological drivers of resource selection and habitat use by moose in interior Alaska Seasonal thermal habitat use and bathymetric distribution of burbot in Tanada and Copper lakes, Alaska Breeding ecology and fasting tolerance of scaup and other ducks in the boreal forest of Alaska Linking local knowledge and fisheries science : the case with humpback whitefish (Coregonus pidschian) in Interior Alaska Winter vertebrate browsing of birch: effects on the use of leaf litter leachates by stream microorganisms Response of northern red-backed vole (Clethrionomys rutilus) populations to a major spruce beetle infestation in the Copper River Basin, Alaska The migration and spawning distribution of sockeye salmon within Lake Clark, Alaska Hepatitis B in Arctic ground squirrels (Spermophylus parryi): epidemiology and population biology Characterization of permafrost development by isotopic and chemical analysis of soil cores taken from the copper river basin and an upland loess deposit in interior Alaska Seasonal thermal habitat use and bathymetric distribution of burbot in Tanada and Copper lakes, Alaska Abundance and timing of summer run Chum salmon (Onchorhynchus keta) and water quality in Clear Creek-Hogatza River, northwestern Alaska Habitat selection by calving caribou of the Central Arctic Herd, 1980-95 Socio-ecological drivers of resource selection and habitat use by moose in interior Alaska Surface water dynamics of shallow lakes following wildfire in Boreal Alaska The effects of climate change on the population dynamics of trumpeter swans The ecological genetics of gynodioecy in Silene acaulis L. (Caryophyllaceae) : spatial sex structure and inbreeding depression Spatio-temporal recruitment dynamics of mountain-dwelling caribou in the Yukon Territory, Canada Yukon Water Availability Analysis: An Assessment of the Potential Impacts of Climate Change on the Balance between Precipitation and Potential Evapotranspiration in the Yukon, Canada Variation of agonistic behavior and morphology among juvenile chinook salmon (Oncorhynchus tshawytscha) of hatchery, wild, and hybrid origin under common rearing conditions Isolation and characterization of photobacterium phosphoreum from migrating Alaskan salmon