• Reindeer Range Appraisal In Alaska

      Pegau, Robert Elwyn (1968)
    • Reindeer, dogs, and horses among the Tozhu reindeer herder-hunters in the Siberian taiga

      Arakchaa, Tayana; Plattet, Patrick; Koester, David; Schweitzer, Peter; Koskey, Michael (2018-12)
      Anthropological studies have typically represented reindeer as the uniquely key domesticated animal species for Siberian people. For Tozhu reindeer herder-hunters, however, such a perspective ignores the important roles of dogs and horses. These species are equally vital and interdependent partners of daily life in the mountainous areas of Tuva where Tozhu people live. Each animal comes with specific characteristics, challenges and benefits that necessitate a multispecies perspective--the reindeer-dog-horse triad of Tozhu hunting and reindeer herding economies. This research completes the picture of how taiga-dwelling Tozhu and the three important animal species co-exist together. It seeks to portray: 1) how the Tozhu reindeer herder-hunters interrelate the role of these animals in hunting and reindeer herding; 2) how their intense crossbreeding of dogs and horses has in turn influenced human-animal relationships; and 3) how humans and animals cooperate with each other to achieve shared goals. An overview of anthropological studies of human-animal relations is presented in Chapter 1 and has revealed that humans and their animals are bound in mutual relations in which humans and animals have reciprocally influenced each other. In discussions of hunting and herding, the basic social concepts of "trust" and "domination," connected to "captivity" and "freedom," have become prominent social concepts for interpreting human-animal relations. In the case of the animals with which Tozhu herder-hunters interact in the taiga, both principles, "trust" and "domination," can be observed, though the widespread idea that animals give themselves to humans is not shared by the Tozhu. Chapter 2 of this thesis provides necessary background on the history of the Tozhu people. Chapter 3 outlines the social organization of reindeer herding and hunting in the Tozhu district of the Tyva Republic and focuses on the history of reindeer herding and hunting during the Soviet and post-Soviet eras, particularly the transition of Tozhu from small to large scale reindeer herding production. Scholars have described this transition as an abrupt change to meat-oriented production. Close scrutiny of the history of Tozhu reindeer herding and hunting reveals that the particularities of the fur trade dictated a gradual shift from small-scale to large-scale reindeer herding in order to provide reindeer hunters and villagers with reindeer to utilize as a means of transportation. Collective farms reconstructed reindeer herding and hunting by introducing new forms and techniques in their economies. Chapter 4 describes the role of reindeer and the nature of human-reindeer relationships among the Tozhu. Chapter 5 focuses on the role of the indigenous breeds of hunting dog, particularly their role in hunting and on crossbreeding during the Soviet era. The chapter also discusses how dog breed, gender, experience, age, and specialization affects hunting. It also examines the stealing and eating of dogs in the Tozhu district. Chapter 6 describes the role of horses in Tyvan ontology and in Tozhu economies. It also discusses crossbreeding during the Soviet and post-Soviet era and how the Tozhu are interfacing with crossbreeds today. Analysis of changes in hunting and reindeer herding organization and the history of dog and horse crossbreeding sheds light on the balancing of human relationships with their animals and animal relationships with their humans. Hunting with dogs, for example, has actually provided a stimulus to domesticate reindeer for riding. The practice of riding allows humans to keep up with the dogs during the search for prey in winter. Tozhu practice also includes maintaining a balance between animal captivity and freedom in order to manage multiple animals successfully. All three species are essential for herder-hunters, and one species cannot be said to be more or less important than the others.
    • The relation of spring pollen release to weather in Fairbanks, Alaska

      Fathauer, Theodore F.; Mölders, Nicole; Bhat, Uma; Wendler, Gerd (2012-08)
      Twenty-three years of pollen data for Fairbanks have been analyzed and related to meteorological data (temperature, wind, relative humidity and precipitation). The purpose of this research is to develop quantitative statistical relationships between weather parameters and the timing and magnitude of pollen release for four taxa native to the Fairbanks area (birch, alder spruce and grass). During the spring and early summer in Fairbanks, dry, sunny and breezy days are common. These conditions are ideal for establishing an unstable boundary layer and its accompanying convective circulation, which can loft large quantities of pollen into the atmosphere. The timing of pollen release varies from season to season by as many as 24 days. Growing degree days based upon daily maximum temperatures and daily minimum relative humidity are the parameters which best define the timing of the onset of significant pollen release. The day-to-day concentration of pollen and the seasonal totals of pollen released can vary by more than an order of magnitude. Weather plays an important part in this because the release of pollen is a result of a drying process accompanied by turbulent circulation, which disperses the pollen.
    • The relationship between the achievement motive and downward communicative adaptability

      Weaver, David E.; Sager, Kevin L.; Dexter, Charlie; Mason, Charles (2019-05)
      In this paper, a model was created linking the Achievement Motive to Downward Communicative Adaptability. As theorized in the model, there is a significant positive relationship between the Achievement Motive and Downward Communicative Adaptability. Participants who supervise or manage others completed an in-person paper and pencil survey. The collected data were entered into an SPSS data file, and a simple correlational analysis was run. A significant positive correlation was found between the Achievement Motive and Downward Communicative Adaptability.
    • Relationship between the aerosol number distribution and the cloud condensation nuclei supersaturation spectrum

      Cantrell, Will Hart, Ii; Shaw, Glenn E. (1999)
      Though Cloud Condensation Nuclei (CCN) are a subset of atmospheric aerosol, relatively little is known of what links the two. A recently developed instrument called the CCN Remover, which directly relates the CCN supersaturation spectrum to the aerosol number distribution, is described. Instrumental errors are quantified and laboratory tests used to verify the instrument's accuracy are also presented. We made measurements with the CCN Remover in the Aerosol Characterization Experiment 2 (ACE 2) and the INdian Ocean EXperiment (INDOEX). These two multinational field campaigns shared the objective of investigating aerosol particles' ability to modulate cloud albedo by activating as CCN. In both instances, we found that aerosol particles were not activating with the characteristics of pure ammonium sulfate, which is generally regarded as the major component of the majority of aerosol particles which act as CCN. Either a substantial fraction of the aerosol was not participating in the activation process or the presence of a hydrophobic surface film inhibited water vapor transport. Measurements of the aerosol's chemical composition and hygroscopic growth factors are used to examine these possibilities. Anthropogenic activity is modifying the properties of natural aerosol particles in a way which could affect their ability to act as CCN. We discuss evidence for aerosol particles coated with sulfuric acid in an Arctic air mass in support of this claim. In some instances, the connection between aerosol and CCN can be inferred directly from the aerosol number distribution. Clouds segregate aerosol into two populations---those that act as CCN and those that do not, and when the cloud evaporates, the aerosol number distribution bears the signature of the cloud through which it has cycled---a minimum in the aerosol number distribution. The diameter at which this minimum occurs can be related to the maximum supersaturation in the cloud, and the number of particles larger than the minimum is the population of particles that acted as CCN. Over 1,000 bimodal aerosol number distributions from five widely separated locations have been analyzed for maximum supersaturation and cloud droplet (or CCN) et (or CCN) concentrations.
    • The relationship between the depth to the 0°C isotherm of the Arctic Ocean and atmospheric forcing

      Moon, Sookmi (2004-05)
      Empirical Orthogonal Function (EOF) analyses of the depth to the 0°C isotherm of the Arctic Ocean were performed to determine the variability of the depth to the 0°C isotherm in the Arctic Ocean. The data are from the 'Environmental Working Group - Joint US. Russian Atlas of the Arctic Ocean.' The first three modes explain 99% of the total variance with each mode explaining 51 %, 26%, and 23%, respectively. Mode 1 shows the pattern of the outflow through Fram Strait and the Lincoln Sea. Mode 2 shows the variability of the inflow from the Barents Sea and the variability of the outflow through the Canadian Archipelago as well as the variability of the Transpolar Drift. Mode 2 has a close relationship with atmospheric conditions (Arctic Oscillation or North Atlantic Oscillation index). Mode 3 is significantly correlated with the annual mean vorticity index, when the vorticity index leads by 1 year. Composite analyses of the data using the AO, NAO, and vorticity index confirm that the EOF analyses of this study are valid. This study shows that the variability of the 0°C isotherm of the Arctic Ocean is significantly correlated with atmospheric conditions.
    • The relationship between the indigenous peoples of the Americas and the horse: deconstructing a Eurocentric myth

      Collin, Yvette Running Horse; Barnhardt, Raymond; Leonard, Beth Ginondidoy; John, Theresa Arevgaq; Oviedo, Marco A. (2017-05)
      This research project seeks to deconstruct the history of the horse in the Americas and its relationship with the Indigenous Peoples of these same lands. Although Western academia admits that the horse originated in the Americas, it claims that the horse became extinct in these continents during the Last Glacial Maximum (between roughly 13,000 and 11,000 years ago). This version of "history" credits Spanish conquistadors and other early European explorers with reintroducing the horse to the Americas and to her Indigenous Peoples. However, many Native Nations state that "they always had the horse" and that they had well established horse cultures long before the arrival of the Spanish. To date, "history" has been written by Western academia to reflect a Eurocentric and colonial paradigm. The traditional knowledge (TK) of the Indigenous Peoples of the Americas, and any information that is contrary to the accepted Western academic view, has been generally disregarded, purposefully excluded, or reconfigured to fit the accepted academic paradigm. Although mainstream academia and Western science have not given this Native TK credence to date, this research project shows that there is no reason -- scientific or otherwise -- that this traditional Native claim should not be considered true. The results of this thesis conclude that the Indigenous horse of the Americas survived the "Ice Age" and the original Peoples of these continents had a relationship with them from Pleistocene times to the time of "First-Contact." In this investigation, Critical Indigenous Research Methodologies (CIRM) and Grounded Theory (GT) are utilized in tandem to deconstruct the history of the horse in the Americas and reconstruct it to include cross-cultural translation, the TK of many Indigenous Peoples, Western scientific evidence, and historical records. This dissertation suggests that the latest technology combined with guidance and information from our Indigenous Peoples has the power to reconstruct the history of the horse in the Americas in a way that is unbiased and accurate. This will open new avenues of possibility for academia as a whole, as well as strengthen both Native and non-Native communities.
    • Relationship maintenance, democratic decision making, and decision agreement

      Tucker, Jenna M.; Sager, Kevin L.; Richey, Jean; Taylor, Karen (2012-05)
      Relationship maintenance uses different strategies to maintain a relationship at the desired level of intimacy. Democratic decision making is a practice through which each individual has equal rights in the decision-making process. The present study investigated connections among two areas of research. In particular, this study examined the correlations among relationship maintenance behaviors, democratic decision making, and decision agreement. Both hypotheses in the study were supported, which suggests relationship maintenance promotes democratic decision making, which in turn promotes decision agreement.
    • Relationships among physical activity, diet, and obesity measures during adolescence

      Maier, Janne Holmberg; Knowler, William; Bersamin, Andrea; Barry, Ronald; Wolf, Diana (2014-08)
      Today's high prevalence of obesity is a concern especially in youth. Physical activity and diet are both important factors associated with weight management, and current recommendations are to consume a diet low in saturated fat and high in fiber, fruit and vegetables and to participate in frequent and regular physical activity. Adherence to recommendations is low, a factor that is strongly correlated with development of obesity and associated chronic diseases such as hypertension and cardiovascular disease. While associations between diet and physical activity are well established, investigation of changes in their association during growth is lacking. This thesis uses five years of diet, physical activity, and anthropometric data from 2379 adolescent girls in the National Heart Lung and Blood Institutes, Growth and Health Study to explore associations among diet, physical activity, and obesity cross-sectionally and with age. Variables representing physical activity, diet quality, and obesity, as well as income, maturation stage, and other potential confounders, were evaluated pair-wise for correlation, and bivariate statistics were examined for longitudinal trends. For further evaluation of relationships between groups of variables we used a canonical correlation analysis. First, physical activity variables were grouped with confounders and examined in relationship to diet quality variables; next, we grouped physical activity, diet quality, and confounders and examined the relationship to obesity measures. We found a moderately increasing correlation between physical activity and diet with age and an age-related decrease in correlation of all health behaviors and confounding variables with obesity measures, indicating that obesity measures become less sensitive to behaviors and socioeconomic factors with age at the same time as health behaviors become more tightly linked. These results suggest that while health behaviors continue to interact during growth, and in fact become more intertwined, measures of obesity become more static and may be less responsive to potential interventions with increasing age. These findings should motivate intervention work to aim for youth as potential impact would be greater before health behaviors and obesity measures become "locked in" to the more static frame of adulthood.
    • Relationships among temperature, depth, and abundance of commercially important fish captured by trawl vessels in the Kodiak area of the Gulf of Alaska, USA

      Barns, Allison Eileen Mercer (2004-12)
      Increased understanding of the factors influencing fish distributions and abundance may improve fisheries management and stock assessment models and may provide the fishing industry with a means to reduce bycatch. I investigated the associations of ambient seawater depth and temperature with catches of commercially important species in the Gulf of Alaska. Time-depth recorders were attached to trawl nets to collect depth and temperature data during commercial bottom trawl fishing operations. The data collected from these recorders were combined with species composition data collected by onboard observers to determine associations between these physical variables and catch of fishes. Parameters for depths and temperatures where target species were abundant were identified. Pacific cod were captured in abundance in depths shallower than 130 m while withstanding water temperatures ranging from 2.8 to 8.5°C. Rockfishes were abundant in depth ranging from 52 m to 353 m and temperatures ranging from 4.9 to 8.3°C. Shallow-water flatfishes were captured in abundance in depths shallower than 97 and temperatures from 2.6 to 10.7°C. Deep-water flatfishes were abundant in depths greater than 115 m and water temperatures ranging from 3.8 to 6.5°C. Arrowtooth flounder, Pacific halibut, and walleye pollock were found in all temperatures and depths analyzed.
    • Relationships between anadromous lampreys and their host fishes in the eastern Bering Sea

      Siwicke, Kevin A.; Seitz, Andrew; Sutton, Trent; Murphy, James (2014-08)
      Arctic Lamprey Lethenteron camtschaticum and Pacific Lamprey Entosphenus tridentatus are ecologically and culturally important anadromous, parasitic species experiencing recent population declines in the North Pacific Ocean. However, a paucity of basic information on lampreys feeding in the ocean precludes an incorporation of the adult trophic phase into our understanding of lamprey population dynamics. The goal of this research was to provide insight into the marine life-history stage of Arctic and Pacific lampreys through lamprey-host interactions in the eastern Bering Sea. An analysis of two fishery-independent surveys conducted between 2002 and 2012 in the eastern Bering Sea revealed that Arctic Lampreys were captured in epipelagic waters of the inner and middle continental shelf and were associated with Pacific Herring Clupea pallasii and juvenile salmonids Oncorhynchus spp. In contrast, Pacific Lampreys were captured in benthic waters along the continental slope associated with bottom-oriented groundfish. Consistent with this analysis of fish assemblages, morphology of recently inflicted lamprey wounds observed on Pacific Cod Gadus macrocephalus was similar to morphology of Pacific Lamprey oral discs, but not that of Arctic Lamprey oral discs. Examination of 8,746 Pacific Cod, of which 4.9% had lamprey wounds, showed recent wounding rates positively increased with fish length up to 78 cm, and penetrating lamprey wounds were less likely to heal compared with superficial lamprey wounds, suggesting lamprey-related mortality. This study elucidates differences in the oceanic ecology between Arctic and Pacific lampreys and suggests a native lamprey can negatively impact hosts, which increases our understanding of lamprey ecology beyond traditional freshwater studies.
    • Relationships between brown bears and chum salmon at McNeil River, Alaska

      Peirce, Joshua McAllister (2007-08)
      Since 1967, the McNeil River State Game Sanctuary (MRSGS) has been managed by the Alaska Department of Fish and Game to 'provide permanent protection for brown bears'. Up to 144 bears have been identified in a summer at MRSGS, and 72 bears at once have been observed in the vicinity of McNeil Falls. In this study, 155 chum salmon were radio tagged as they entered McNeil River and monitored daily. In 2005 and 2006 bears killed 48% of pre-spawning tagged chum salmon and consumed 99% of all tagged chums below McNeil Falls where most of the run occurs. A retrospective analysis of 31 years of run data using a new stream life, and a correction for observer efficiency, revealed that the current escapement goal of 13,750-25,750 actually represents 34,375-64,375 chum salmon. Considering the large removal of pre-spawning chum salmon, I recommend an additional 23,000 chum salmon be added to the escapement goal. Additionally, an annual escapement of 4,000-6,000 chum salmon above McNeil Falls should be set as an objective. These recommendations should encourage increased chum salmon returns, providing both food for McNeil bears, as well as benefiting the commercial fishery with increased harvest opportunities.
    • Relationships between ecosystem metabolism, benthic macroinvertebrate densities, and environmental variables in a sub-Arctic Alaskan river

      Benson, Emily R. (2010-08)
      The aim of this study was to investigate the environmental drivers of river ecosystem metabolism and macroinvertebrate density in a sub-arctic river. Ecosystem metabolism is the combination of gross primary production and ecosystem respiration within a river. Aquatic macroinvertebrates link primary producers at the base of the food web with secondary consumers. The extent to which photosynthetically active radiation, discharge, and nutrients influence metabolism rates and how primary production and river discharge rates influence benthic macroinvertebrate densities in sub-arctic rivers is not clear. These processes ultimately help regulate prey resources available for upper level consumers such as juvenile salmon. I employed Random Forests model analyses to identify important predictor variables for primary production and respiration rates (estimated using the single-station diel oxygen method) at four sites in the Chena River, sub-arctic Alaska, throughout the summers of 2008 and 2009. I calculated Spearman correlations between nutrient levels and metabolism rates. I used Random Forests models to identify the variables important for predicting benthic macroinvertebrate density and biomass at the study sites. The models indicated that discharge and length of time between high water events were the most important variables measured for predicting metabolism rates. Discharge was identified as the most important variable for predicting benthic macroinvertebrate density and biomass. Phosphorus concentration was low (at times below the detection limit), while nitrogen concentration was more variable; the ratio of nitrogen to phosphorus was above the threshold for phosphorus limitation, suggesting that phosphorus may have been limiting primary production.
    • Relationships between succession and community structure and function of Alnus-associated ectomycorrhizal fungi in Alaskan boreal forests

      Swanson, Michaela M.; Ruess, Roger; Taylor, D. Lee; McFarland, Jack; Kielland, Knut (2016-08)
      Rates of production and carbon cycling in northern ecosystems depend heavily on nitrogen (N) availability across the landscape. Since much of the available N enters these systems through biological N-fixation, Alnus, with its capacity to fix large amounts of N, plays a critical role in ecosystem response to environmental change. However, because of its high phosphorus (P) demands, the abundance, distribution, and N-fixing capacity of Alnus is tightly controlled by the availability of P and its ability to assimilate P by associating with ectomycorrhizal fungal (EMF) symbionts. We assessed the potential of A. tenuifolia-associated EMF to access organic P forms of varying complexities. More than half of the community on A. tenuifolia were individuals from the genera Alnicola and Tomentella, indicating that the community of EMF on Alnus is a relatively distinct group of host-specific ectomycorrhizal fungi. However, the aggregated acid phosphatase, phosphodiesterase and phytase activities of the Alnus-EMF community were not dramatically different from other boreal plant hosts on the root tip level. We detected variability in the activities of the two Alnus dominants to mobilize acid phosphatase and phosphodiesterase. However, it appears that contrary to the hypothesis that nitrogen-fixing species would associate with EMF types well suited to P acquisition, the potential acid phosphatase activity of Alnicola luteolofibrillosa was significantly below the community mean. Our finding that enzyme activities of Alnus-EMF are not substantially greater than those found on other plant hosts suggests that if host specific EMF on Alnus facilitates P mobilization and uptake, the steps between P hydrolysis and assimilation into plant tissue as well as other pathways of P acquisition may be of greater importance in determining P provisioning to Alnus by EMF.
    • Relative sea level change in western Alaska estimated from satellite altimetry and repeat GPS measurements

      DeGrandpre, Kimberly Grace; Freymueller, Jeffrey; Kinsman, Nicole; Nadin, Elisabeth (2015-08)
      Western Alaska is a remote region populated by small coastal communities that are sensitive to variations in local relative sea level (RSL). The focus of this thesis is to address two main questions; what are the RSL trends in Western Alaska and what are the geophysical processes that contribute to the changes observed? Quantification of RSL variation requires measuring vertical velocities for both land surface motion (onshore component) and the ocean surface (offshore component). This study presents a new method for coastal satellite altimetry estimation, the collection of historic water level measurements, analysis of tide gauge measurements from various sources, GPS vertical velocity model for Western Alaska, estimation of an Earth model and glacial isostatic adjustment (GIA) vertical velocities for Northern and Western Alaska, and RSL change model for Western Alaska. The findings of this study result in a GIA model that predicts measured GPS velocities well. The predicted GIA vertical velocities average -1.06 mm/yr in Western Alaska and are combined with the averaged satellite altimetry cells that exhibit a mean sea level change offshore of Western Alaska of -0.27 mm/yr to produce a RSL change model for Western Alaska that increases approximately +0.79 mm/yr in the region.
    • Reliability analysis of reconstructing phylogenies under long branch attraction conditions

      Dissanayake, Ranjan; Allman, Elizabeth; McIntyre, Julie; Short, Margaret; Goddard, Scott (2018-05)
      In this simulation study we examined the reliability of three phylogenetic reconstruction techniques in a long branch attraction (LBA) situation: Maximum Parsimony (M P), Neighbor Joining (NJ), and Maximum Likelihood. Data were simulated under five DNA substitution models-JC, K2P, F81, HKY, and G T R-from four different taxa. Two branch length parameters of four taxon trees ranging from 0.05 to 0.75 with an increment of 0.02 were used to simulate DNA data under each model. For each model we simulated DNA sequences with 100, 250, 500 and 1000 sites with 100 replicates. When we have enough data the maximum likelihood technique is the most reliable of the three methods examined in this study for reconstructing phylogenies under LBA conditions. We also find that MP is the most sensitive to LBA conditions and that Neighbor Joining performs well under LBA conditions compared to MP.
    • Remote sensing and GIS analysis of the spatial and morphological changes of thermokarst lakes: Kolyma lowlands, northeast Siberia

      Tillapaugh, Meghan L. (2011-05)
      Thermokarst lakes develop when changes in the permafrost thermal regime cause degradation leading to surface subsidence and ponding. The degree of thermokarst development depends upon permafrost characteristics, topography, and geology. Changing thermokarst lake dynamics affect arctic ecosystems, hydrological patterns, albedo, and the carbon cycle through the mobilization of organic matter in the permafrost. This study used remote sensing and GIS techniques to relate lake dynamics in the Kolyma Lowlands, Siberia, to geology, elevation, geomorphological features, hydrology, and air temperature. Highest limnicity and largest lake sizes were found in regions with low elevation, limited alluvial processes, high ground-ice content, and lithologies with small particle sizes. New lake development and erosion occurred as well. One subregion studied showed lake area increases (Cherskii: +7.6%) while another showed a decrease (Duvanny Yar: -5.2%). Differences are attributed to variations in elevation and fluvial influences. A major cause of drainage was river tapping of lakes. Lake coalescence, flooding during river water level high stands, and lakeshore erosion were the main causes of lake expansion. The Kolyma Lowland soils have high ice and organic matter contents as well making the monitoring of thermokarst lake dynamics important as large amounts of freshwater and carbon could potentially be released.
    • Remote Sensing of Arctic Landscape Dynamics

      Jones, Benjamin M.; Grosse, Guido; Arp, Christopher; Mann, Daniel; Romanovsky, Vladimir; Verbyla, David (2013-12)
      Amplified warming in the Arctic has likely increased the rate of landscape change and disturbances in northern high latitude regions. Remote sensing provides a valuable tool for assessing the spatial and temporal patterns associated with arctic landscape dynamics over annual, decadal, and centennial time scales. In this dissertation, I focused on remote sensing studies associated with four primary components of arctic landscape change and disturbance: (1) permafrost coastline erosion, (2) thermokarst lake dynamics, (3) tundra fires, and (4) using repeat airborne LiDAR for the measurement of vertical deformation in an arctic coastal lowland landscape. By combining observations from several high resolution satellite images for a 9 km segment of the Beaufort Sea Coast between 2008 and 2012, I demonstrated that the report of heightened erosion at the beginning of the 2000s was equaled or exceeded in every year except 2010 and that the mean annual erosion rate was tightly coupled to the number of open water days and the number of storms. By combining historical aerial photographs from the 1950s and 1980s with recent high-resolution satellite imagery from the mid-2000s, I assessed the expansion and drainage of thermokarst lakes on the northern Seward Peninsula. I found that more than half of the lakes in the study area were expanding as a result of permafrost degradation along their margins but that the rate of expansion was fairly consistent (0.35 and 0.39 m/yr) between the 1950s and 1980s and 1980s and mid-2000s, respectively. However, it appeared that in a number of instances that expansion of lakes led to the lateral drainage and that over the 55-year study period the total lake area decreased by 24%. While these studies highlight the utility of quantifying disturbance during the remotely sensed image archive period (~1950s to present) they are inherently limited temporally. Thus, I also demonstrated techniques in which field studies and remote sensing data could be combined to extend the identification of landscape disturbance events that occurred prior to the remote sensing archive. I identified two large regions indicative of past disturbance caused by tundra fires on the North Slope of Alaska, which doubled the delineated area of tundra fire disturbance on the North Slope over the last 100 to 130 years. I conclude the dissertation by demonstrating the utility of repeat airborne light detection and ranging (LiDAR) data for arctic landscape change studies, in particular vertical surface deformation, and provide momentum for going forward with this emerging technology for remote sensing of arctic landscape dynamics. The quantification of arctic landscape dynamics during and prior to the remote sensing archive is important for ongoing monitoring and modeling efforts of the positive and negative feedbacks associated with amplified Arctic climate change.
    • Remote sensing of burn severity and the interactions between burn severity, topography and vegetation in interior Alaska

      Epting, Justin Frederick (2004-08)
      A variety of single-band, band ratio, vegetation index, and multivariate algorithms were evaluated for mapping burn severity using Landsat TM and ETM+ imagery across four burns in interior Alaska. The Normalized Burn Ratio (NBR) outperformed all algorithms, both when tested as a single post-fire value and when tested as a differenced (prefire-postfire) value. The NBR was then used to map burn severity at a historical burn near Yukon-Charley Rivers National Preserve and a time-series of images from 1986 to 2002 was analyzed to investigate interactions between vegetation, burn severity, and topography. Strong interactions existed between vegetation and burn severity, but the only topographic variable that had a significant relationship with burn severity was elevation, presumably due to the strong control of elevation on vegetation type. The highest burn severity occurred in spruce forest, while the lowest occurred in broadleaf forest. Areas with high burn severity experienced disproportionately more shifts toward spruce woodland and shrub classes, while areas with low to moderate severity were less likely to change vegetation type. Finally, vegetation recovery, estimated using a remotely-sensed vegetation index, peaked between 8-14 years post-fire, and recovery was highest for areas with the highest burn severity.
    • Remote sensing of erosion and shallow water bathymetry to aid river navigation on the Colville River, Nuiqsut AK

      Payne, Cole S.; Panda, Santosh; Prakash, Anupma; Brinkman, Todd (2018-08)
      The Colville is the longest river (~600 km) in Arctic Alaska. Nuiqsut is an established Alaska Native community of ~400 people on the Colville River. Its residents rely heavily on the Colville for subsistence needs, however, changing river dynamics caused by accelerated bank erosion, river siltation, low water, and shifting and drying channels are causing concern and making boat travel increasingly difficult and dangerous. Recently, local residents have reported increased erosion at bluff sites along the Colville, which threatens existing infrastructure. Also reported are unexpected shallow water sections along the main channel of the Colville, limiting their access to subsistence food sources. Residents have expressed a need for monitoring erosional rates on the Colville as well as a map product that could aid in river navigation. These concerns shaped the main goals of this Thesis: 1) To use remote sensing techniques to map and quantify erosion rates and the volume of land loss at selected bluff sites along the main channel of the Colville, and to assess the suitability of automated methods of regional erosion monitoring. 2) To use optical satellite images for mapping river bathymetry and generate GIS map products that show potential shallow water sections (<2m) and poor channel connections, and to assess the feasibility of future monitoring based off our methods that rely on extracting relative water depth values from publicly available optical remote sensing images. For our erosional study we used orthomosaics from high resolution aerial photos acquired in 1955 and 1979/1982, as well as high resolution WorldView-2 images from 2015 to quantify long-term erosion rates and the cubic volume of erosion. We found that, at the selected sites, erosion rates averaged 1 to 3.5 m per year. The erosion rate remained the same at one site and increased from 1955 to 2015 at two of the four sites. We estimated the volume of land loss to be in the magnitude of 166,000 m³ to 2.5 million m³ at our largest site. We also found that estimates of erosion were comparable for manual hand-digitized and automated methods, suggesting our automated method was effective and can be extended to monitor erosion at other sites along river systems that are bordered by bluffs. For our bathymetry study we used summer 2017 scenes from three optical sensors (PlanetScope 3m, Sentinel 2 10m, and Landsat 30m) along with field measurements on the river to map shallow water bathymetry along a 45 km stretch of the Colville. We found a strong correlation (R²=0.89) between field-measured water depths and image-derived reflectance quantity (natural log ratio of green over red bands). We analyzed the two essential criteria for suitable bathymetry mapping from optical images: clear weather and clear water conditions. We expect several days (≈16) of suitable conditions during the ice-free season to facilitate reliable bathymetry mapping and remote monitoring of shallow water sites. We also discuss a relative depth mapping technique which is useful for boat navigation in the absence of ground truth measurements. We deliberately employed simple and robust empirical techniques that could serve as a basis for a fully developed river monitoring project in the near future led by local community residents. An implementation of our methods by the community, in order to develop a river depth monitoring program, would be an important step forward for the advancement of community-based science and the co-production of knowledge. Our technique may help address emerging environmental and societal issues in other regions where sufficient river navigation fosters local livelihoods.