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In the North American boreal forest, 21st century climate change is projected to result in longer growing seasons, increased forest productivity, and northward expansions or shifts in species ranges. These projected impacts are largely based on observations across natural temperature gradients, e.g., latitude or altitude, or correlations between current species' distributions and modern climate envelopes. These approaches, although valuable, do not consider biological capacities important in a species' ability to cope with novel environments through physiological or phenological acclimation. Within a single species, adaptation to local environments may cause some populations to respond differently to climate change...
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Slow growing white spruce (Picea glauca) seedlings and saplings often become established early in succession and mature through several succession seres. During early succession, spruce often germinate in mineral soils and become established in alder (Alnus tenuifolia or A. crispa) thickets, with the potential for both competitive and facilitative relationships. Although competitive and facilitative plant interactions are often identified by changes in the growth or density of the interacting species, the result of the interaction will depend upon the individual plant's physiological acclimation to abiotic changes caused by neighboring plants. This study analyzes components of photosynthesis to provide information...
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Summary: "Little is known about natural attenuation of chlorinated solvents in subarctic ground water. This study aimed to better understand the biogeochemistry and microbiology associated with naturally occurring processes of contaminent removal at two hydrologically diverse sites near Fairbanks, Alaska. Six Mile Village, located several km north of the Tanana River, is hydrologically stable, experiencing minor fluctuations in ground-water levels. Fort Wainwright is located adjacent to the Chena River and is hydrologically dynamic, experiencing seasonal flow reversals and substantial fluctuations in water-table elevations. By comparing data collected seasonally and with data collected at the two sites, I determined...
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The use of operative environmental temperature (Te) has been a major advance in the study of thermal ecology. I review the use of operative temperature in thermal biology with an emphasis on insects. Then I use data from dragonflies in Interior Alaska (Odonata: Anisoptera) to compare the efficacy of operative and ambient temperature when examining thermoregulating ability. I conclude that although the use of Te may provide more accurate measures of thermoregulation under specific environmental conditions, the use of ambient temperature usually leads to the same conclusions about thermoregulating ability. I next examine the relationships between thermoregulating ability, minimum flight temperature (MFT), mass, passive...
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Climate models and studies indicate that the changes in the northern latitudes will be serious and accelerated. Climate warming may impact structures in the northern latitudes through permafrost settlement affecting the performance of infrastructure and increasing costs for maintenance. The material presented is organized in three main chapters. Chapter 1 describes the motivation for the research. Chapter 2 addresses the permafrost settlement hazard in Alaska. I developed the Permafrost Settlement Hazard Index, which considered anticipated climate warming and ecological characteristics which regulate permafrost settlement. I found that the discontinuous permafrost region is at more risk due to permafrost settlement...
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The objective of this dissertation was to estimate the magnitude and mechanisms of lake area change in Alaskan National Wildlife Refuges. An efficient and objective approach to classifying lake area from Landsat imagery was developed, tested, and used to estimate lake area trends at multiple spatial and temporal scales for ∼23,000 lakes in ten study areas. Seven study areas had long-term declines in lake area and five study areas had recent declines. The mean rate of change across study areas was -1.07% per year for the long-term records and -0.80% per year for the recent records. The presence of net declines in lake area suggests that, while there was substantial among-lake heterogeneity in trends at scales of...
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The Kenai River Watershed (KRW), in south-central Alaska, is famous for its salmon. Urbanization along the lower river damages habitat and stresses these valuable fish. Are the river's salmon runs sustainable if recent land-use trends continue? I used interdisciplinary approaches from environmental history and landscape science plus technologies such as geographic information systems (GIS) to describe the watershed's land-use history from 1947 to 2010 and to link land use and watershed management to the sustainability of salmon runs. Although the area appears wild compared to many salmon-producing watersheds in other states, it has a long history of intense use and habitat degradation. Over the past 60 years the...
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"As the climate changes, Alaska's boreal forest faces the simultaneous threats of rising invasive plant abundances and increasing area burned by wildfire. Highly flammable and widespread black spruce forest represents a boreal habitat that may be increasingly susceptible to non-native plant invasion. In other biomes, non-native plant invasions are generally greatest in high severity burns that are only a few years old. The relationship between fire and non-native plant invasion has not been investigated in the northern boreal forest. To assess the invasibility of burned black spruce forests, I used burned field sites that spanned a gradient of burn severities, moisture levels, and burn ages. I conducted both field...
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Analytical methods for determining polycyclic aromatic hydrocarbon (PAH) concentrations in spruce needles were developed and evaluated. Concentrations of four PAHs (phenanthrene, anthracene, fluoranthene and pyrene) were determined in spruce needles collected near Eastern Alaska roadways. These needle concentrations were used to develop multivariate models that described the influence of climate and geographical variables on concentrations. These variables included latitude, longitude, radial distance from urban site, elevation, temperature, precipitation, ecosystem type, tree species, non-volatile extractable content of needles, and forest fire impact. The models show that three possible sources of PAHs exist in...
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The Late Cretaceous Matanuska Formation contains shallow and deep marine sediments and nonmarine sediment derived from the Talkeetna volcanic island arc. The sediment accumulated in the Matanuska Seaway, a tectonically active basin on the southern margin of southcentral Alaska. The Matanuska Seaway was contemporaneous with the Cretaceous Western Interior Seaway (CWIS) of North America. Angiosperm pollen taxa from the CWIS have been used to date units and reconstruct both paleolatitude and paleoclimate (Nichols and Sweet, 1993). Comparison of pollen taxa from the CWIS to assemblages from the Matanuska Formation reveals that outcrops at Mazuma Creek, Granite Creek, Syncline Mountain, and Slide Mountain are Late Maastrichtian,...
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I utilized the ecological diversity displayed in the Cook Inlet adaptive radiation of threespine stickleback (Gasterosteus aculeatus species complex, hereafter 'stickleback') to examine the drivers of intra- and inter-population variation in total mercury (THg) concentrations. I examined the importance of sex, trophic position (TP), and habitat-specific foraging (measured as the proportion of the diet derived from benthic sources; alpha ) in stickleback from Benka Lake, Alaska, a lake with both benthic and limnetic ecotypes. The results demonstrate that both sex and habitat-specific foraging are important determinants of THg concentrations in this threespine stickleback population. Specifically, male stickleback...
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In several populations of pink salmon, the short-term dynamics population size was related to both the mean and variance of individual family sizes, because not all families were equally productive. In the marine lifestage, population increases came disproportionately from the most productive families, especially in populations with the highest average marine survival. Moreover, the trait of marine survival itself had a statistically detectable genetic component. This implies that the most favored phenotypes change from generation to generation, and that the marine environment is unpredictable and changing. These results, together with laboratory studies of freshwater survival and measurements of wild pink salmon...
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The Alaska Native Claims Settlement Act was an experiment and a radical departure from policies in creating corporations with all shareholders being equal. The replication of publicly traded corporate governance has created frustrations, inequities, and unintended consequences for thousands of Natives which can be righted only if the experiment is continued. This is not a history of land claims but an attempt to unravel a tangled web of leadership, political, and rural development issues that are intimately interwoven with ANCSA corporations. This paper is not about second guessing the leadership of the movement but about the need to understand how difficult it is to create rural development on corporate lands whose...
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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...
map background search result map search result map Photosynthetic acclimation of white spruce (Picea glauca) to canopy microhabitats An investigation of environmental variables affecting concentrations of polycyclic aromatic hydrocarbons in eastern Alaska Natural attenuation of chlorinated solvents in subarctic ground water Modeling the influences of climate change, permafrost dynamics, and fire disturbance on carbon dynamics of high-latitude ecosystems Temporal and spatial distribution of interior Alaska white-fronted geese (Anser albifrons frontalis) during fall migration and winter staging Evidence for a northern transitional continental margin flora in the Cretaceous (Campanian to Maastrichtian) Matanuska Formation, Talkeetna Mountains, southcentral Alaska Reproductive biology and movement patterns of humpback whitefish and least cisco in the Minto Flats-Chatanika River complex, Alaska Ecological drivers of mercury accumulation in threespine stickleback fish Lake area change in Alaskan National Wildlife Refuges: Magnitude, mechanisms, and heterogeneity Variability of pink salmon family size has implications for conservation and management models 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 Evapotranspiration in a subarctic agroecosystem: Field measurements, modeling and sustainability perspectives Wildfire burn susceptibility to non-native plant invasions in black spruce forests of interior Alaska Thermoregulating ability and minimum flight temperature in interior Alaska dragonflies (Odonata: anisoptera) The history of land use on Alaska's Kenai River and its implications for sustaining salmon Acclimation and migration potential of a boreal forest tree, balsam poplar (Populus balsamifera L.) in a changing climate Climate-induced changes in ecological dynamics of the Alaskan boreal forest: a study of fire-permafrost interactions Evapotranspiration in a subarctic agroecosystem: Field measurements, modeling and sustainability perspectives Modeling the influences of climate change, permafrost dynamics, and fire disturbance on carbon dynamics of high-latitude ecosystems Wildfire burn susceptibility to non-native plant invasions in black spruce forests of interior Alaska Climate-induced changes in ecological dynamics of the Alaskan boreal forest: a study of fire-permafrost interactions Photosynthetic acclimation of white spruce (Picea glauca) to canopy microhabitats Natural attenuation of chlorinated solvents in subarctic ground water Thermoregulating ability and minimum flight temperature in interior Alaska dragonflies (Odonata: anisoptera) Evidence for a northern transitional continental margin flora in the Cretaceous (Campanian to Maastrichtian) Matanuska Formation, Talkeetna Mountains, southcentral Alaska Reproductive biology and movement patterns of humpback whitefish and least cisco in the Minto Flats-Chatanika River complex, Alaska Variability of pink salmon family size has implications for conservation and management models The history of land use on Alaska's Kenai River and its implications for sustaining salmon 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 Ecological drivers of mercury accumulation in threespine stickleback fish Temporal and spatial distribution of interior Alaska white-fronted geese (Anser albifrons frontalis) during fall migration and winter staging Lake area change in Alaskan National Wildlife Refuges: Magnitude, mechanisms, and heterogeneity An investigation of environmental variables affecting concentrations of polycyclic aromatic hydrocarbons in eastern Alaska Acclimation and migration potential of a boreal forest tree, balsam poplar (Populus balsamifera L.) in a changing climate