• Reevaluating recent temporal trends in animal body size: the role of demography

      Theriot, Miranda K.; Olson, Link; Doak, Patricia; Millien, Virginie (2021-05)
      Climate change over recent decades is associated with varied responses in animals, including both increases and decreases in body size. These opposing trends are often attributed to two primary hypotheses. In warm-blooded vertebrates, Bergmann's rule predicts decreases in average size with increasing temperature, based on the relationship between body size and thermoregulation. Alternatively, increased average body size is linked with changes in resource availability as summer growing seasons lengthen and winters becomes milder. We propose a third explanation, that shifts in demography underlie some of these observed trends, as many species change in size or shape throughout life. The influence of thermoregulatory demands, resources, and demography on body size trends are not mutually exclusive; disentangling these effects and identifying overarching patterns requires detailed analyses across multiple locations and taxa, which in turn necessitates repeatable and expandable studies. To that end, here we propose three best practices in body size research: defining and justifying measures of size, citing museum specimens, and accounting for demography. We employed these guidelines in a study on masked shrews (Sorex cinereus) in Alaska. We found evidence of age-based differences in total body length, tail length, skull length, and skull width; however, correcting for age did not have a strong effect on the apparent trends in size over time. Based on linear mixed models, mean total length and tail length increased from 1951-1991, consistent with previous findings. Additionally, our results revealed slight increases in mean skull length and toothrow length over the 40-year study period. There was some indication of differing trends between age classes in both of these measurements. These results were not statistically significant, but our sample size of overwintered adults was relatively small, so further study is needed to fully investigate age-specific size trends in masked shrews. In summary, this thesis highlights the importance of repeatability in body-size research and emphasizes the importance of demography in the study of these trends.
    • Reproduction and stress response endocrinology in blue (Balaenoptera musculus) and gray (Eschrichtius robustus) whales

      Melica, Valentina; Atkinson, Shannon; Mueter, Franz; Tamone, Sherry; Gendron, Diane; DeMaster, Doug (2020-12)
      Identification of biomarkers that reflect physiological status is fundamental for assessing population health, as well as providing more accurate estimates of life history parameters. Blue (Balaenoptera musculus) and gray (Eschrichtius robustus) whale populations feed on lower trophic levels and migrate between the eastern Tropical and the eastern North Pacific Ocean. With increasing disturbances (e.g., changing environment and human activities), understanding the stress response, resultant coping mechanisms, and the subsequent effects on reproduction, is of growing importance. While extensive knowledge is available on photo-identification and ecology of these two species, information on physiology is limited and what exists is outdated. This dissertation validated and measured a suite of steroid hormones in blubber tissue using an enzyme immunoassay technique to develop physiological biomarkers for reproduction and metabolism in these two species. Coupled with sighting history data, progesterone and testosterone were validated as biomarkers for reproductive physiology. In both species, progesterone concentrations were higher in pregnant females and mixture models were developed to estimate reproductive status for whales of unknown status. Testosterone showed greater variability in adult males and concentrations were higher in samples collected during fall, suggesting physiological preparation for mating. Additionally, progesterone concentrations in gray whales were higher in calves of both sexes, indicating maternal transfer through lactation, while in blue whales, testosterone was detectable only in males and in pregnant whales, suggesting its biosynthesis or metabolism is altered during gestation. Biomarkers for stress response were developed through analytical and biological validation of three corticosteroid hormones: cortisol, corticosterone and aldosterone. First, analytical validations (i.e., parallelism and accuracy tests) were used to determine detectability and measurement accuracy of these hormones using commercially available kits. Hormone concentrations were tested for any relationships with life history parameters (e.g., age and reproductive state) as well as with area and time of sampling within presumably "healthy" (biopsies) whales and "stressed" (stranded) whales. "Stressed" whales, especially those that perished due to trauma and/or nutritional stress, had higher concentrations of all three corticosteroid hormones than "healthy" whales, suggesting ongoing alteration of metabolic status due to a stress response. In female "healthy" whales, reproductive status appeared to be a major factor influencing corticosterone concentrations in blue whales and for cortisol in gray whales. Overall, cortisol was determined to be a valid marker for body conditions in both species. These results set a milestone for assisting to better understand the impact of a changing environment on the physiology of these species and can be used to develop more accurate reproductive and survival rates to use in population dynamics models for management of subsistence resources and for conservation of endangered species.
    • The reproductive biology of yelloweye rockfish (Sebastes ruberrimus) in Prince William Sound and the Northern Gulf of Alaska

      Arthur, Donald E.; Falke, Jeffrey; Beaudreau, Anne; Sutton, Trent; Blain-Roth, Brittany (2020-12)
      Over the last half century, Yelloweye Rockfish Sebastes ruberrimus have experienced dramatic declines along the West Coast of the United States and British Columbia. Efforts have been made throughout the species' range to rebuild and sustainably manage stocks, including the introduction of a Statewide Rockfish Initiative by the State of Alaska, which intends to develop management strategies for Yelloweye Rockfish in the Gulf of Alaska. To support this effort and address information gaps in Yelloweye Rockfish reproductive biology throughout their range, I estimated important reproductive parameters and life history information for Yelloweye Rockfish in Prince William Sound and the Northern Gulf of Alaska, Alaska, that included maturity, parturition timing, skip spawning, and fecundity relationships. I identified that ages-at-50% maturity (A50) for males and females were similar (A50 = 15 years and A50 = 16, respectively), but males reached full maturity (A95) earlier than females (male A95 = 19 years and female A95 = 31 years). Female Yelloweye Rockfish fork length-at-50% and 95% maturity (L50 and L95) was greater in the Northern Gulf of Alaska (L50 = 46.7 cm and L95 = 55.8 cm) than in Prince William Sound (L50 = 41.1 cm and L95 = 50.2 cm). Similarly, male L50 and L95 was greater in the Northern Gulf of Alaska (L50 = 44.0 cm and L95 = 49.2 cm) relative to Prince William Sound (L50 = 40.8 cm and L95 = 46.0 cm), and males matured at a smaller size than females. Female L50 was consistent with data from southern populations, but A50 was younger than predicted based on a latitudinal trend, indicating that Yelloweye Rockfish in this region may experience greater than expected growth rates. Yelloweye Rockfish underwent parturition between May and August and peaked in June and July, and parturition timing was earlier for larger and older females. I documented that female Yelloweye Rockfish skip-spawned at a rate of 9.8%. Skip spawning rate was associated with fork length and peaked at sizes between 40.2 cm and 52.3 cm; the peak in stock reproductive potential is shifted toward larger females in response to skip spawning. I conducted egg and larvae counting in an image-analysis software, which was more than four times faster than manual counting and was equally accurate and precise. Yelloweye Rockfish fecundity scaled hyperallometrically with FL and relative fecundity increased with length, indicating that spawning stock biomass may not be proportional to total egg production. Combining these results, I found that ignoring the hyperallometric fecundity relationship and skip spawning could overestimate reproductive potential by as much as 66% and 45% for Prince William Sound and the Northern Gulf of Alaska, respectively. The results of this study will improve the estimates of stock-recruitment dynamics and can be readily integrated into a stock assessment that will guide the sustainable management of Yelloweye Rockfish in Prince William Sound and the Northern Gulf of Alaska.
    • The rocky shores of Prince of Wales, Alaska: intertidal ecology, abalone, and community sustainability

      Bolwerk, Ashley; Eckert, Ginny L.; Carothers, Courtney; Dethier, Megan (2021-05)
      Rocky, nearshore ecosystems are diverse and dynamic environments that function as the link between land and sea and provide important resources for people. In this two-part thesis, I first examined rocky intertidal ecological communities to better understand biotic and abiotic drivers in this system, and then I investigated the abundance of pinto abalone (Haliotis kamtschatkana), a key subsistence resource that local community members identified as the most important because of limited harvest and drastic declines. Pinto abalone are tied to Haida subsistence, culture, and spiritual identity and have been a traditional harvest species for the Haida people for millennia. Pinto abalone were harvested by non-Native fishermen through heavy commercial (1970-1996) and personal use harvest, causing a crash of the population. In the rocky intertidal I surveyed the upper and lower extents of major biobands, frequency of occurrence of sessile organisms, and abundance of mobile invertebrates across a vertical gradient at 18 sites near the west coast of Prince of Wales Island. A multivariate approach was used to identify the major drivers of rocky intertidal community composition and structure. Sea otter (Enhydra lutris) occupation time, average fetch, beach aspect, rugosity, and rock texture were all identified as influential forces for at least one tidal zone and/or biological metrics. Sea otters were not found to restructure the ecosystem, as they do in deeper kelp forest habitats. To assess the current viability of pinto abalone harvest, concerns about sustainability, and their ecological relationships, I partnered with local harvesters within the community of Hydaburg on Prince of Wales Island to combine Indigenous Knowledge about pinto abalone harvest with SCUBA surveys at historically productive traditional harvest sites. Only four (out of 17) of our shallow transects (2 x 20 m), which are within the depth range for traditional harvest methods, had legal-sized pinto abalone (max = 1 abalone). The traditional pinto abalone harvest fishery failed three out of four fishery recovery criteria that were examined. Fourteen out of eighteen sites did not have large (≥ 100 mm) pinto abalone, and pinto large abalone densities were below 0.1 abalone/m2 at all sites. All intermediate size classes of pinto abalone were represented within the fishery, but only 20% of large size classes were observed. Low pinto abalone abundance leads to concerns about traditional harvest viability and spawning failure and thus recruitment failure, for this density-dependent spawning species. In our generalized linear models, pinto abalone presence, density, and biomass were affected by sea urchin biomass. This baseline study of the current state of pinto abalone at traditional harvest sites bestows critical information to a community that depends on pinto abalone as a resource. The Hydaburg Cooperative Association, as a federally recognized Tribe, can use this information to make local management decisions, which include adjustments to harvest guidelines, implementation of sea otter management zones, and/or the establishment of pinto abalone restoration projects. Working with the Tribe and community members throughout the research process led to better science, applicable data, and took a step toward equity and reciprocity in the research processes.
    • Safety analysis of off-highway vehicles use within public rights-of-way in Alaska

      Sayre, Tristan; Belz, Nathan; Barnes, David; Falchetto, Augusto (2020-08)
      Many Alaskans own and operate off-highway vehicles (OHVs) for recreational purposes or for use as primary and secondary modes of transportation. However, the reported crash rate shows that 80 on-road crashes, resulting in five fatalities, occur each year statewide. As a result, the use of OHVs has been identified as a safety concern in the Alaska State Highway Safety Improvement Plan. Minimal research dedicated to understanding OHV use in Alaska exists which limits the potential for improvements that address safety concerns in an equitable fashion. The research presented here contributes to better understanding of on-road OHV use through observational and retrospective analysis. Field-based observations were conducted within highway rights-of-way in 14 strategic locations across Alaska to quantify OHV use and the risk-taking behaviors of riding without helmets, passengers riding without a designated seat, and riding unlawfully on the road. Additional risk factors from the field observations and Alaska Department of Motor Vehicles (DMV) crash data for the period from 2000 through 2016 were identified using the Chi-Square test for independence. Spatial analysis of the Alaska DMV crash data for the period from 2009 through 2016 tested for complete spatial randomness of crashes and identified clusters of crashes by frequency and severity using neighborhood point density statistics. Frequent OHV use was observed with daily traffic volumes exceeding 40 vehicles per day in three field study locations. Several risk-tolerant behaviors were observed including users riding without helmets and vehicles carrying passengers without a designated seat an average of 70 and 20 percent of the time, respectively. Additionally, over half the OHV users were observed to be riding unlawfully using the road. Risk-tolerant behaviors were most frequently observed in communities where on-road use is legal and happened to be coincident with the highest on-road use rates. Overrepresented risk factors for high crash severity incidents included riding at night, in summer, on unpaved roads, on local roads or collectors, in rural areas, for single-vehicle crashes with the occupant not using safety equipment and riding under the influence of alcohol. Crashes were observed to be clustered around towns with the highest frequencies occurring near town centers. The prevalence of risk-tolerant riding behaviors and unlawful on-road riding indicates the need for improvements to existing laws and the education and enforcement thereof. Changes must address the unique needs of users while also considering local jurisdiction such that safety can be improved while also maintain transport equity for residents of rural and isolated communities in Alaska.
    • Salmonid distribution models to support restoration planning across the fragmented Chehalis River basin, WA

      Walther, Eric J.; Westley, Peter; Zimmerman, Mara; Falke, Jeffrey; Seitz, Andrew (2021-05)
      Understanding the factors that influence the distribution of species through time and across space is a fundamental goal of ecology and crucial information needed to effectively manage and recover populations. Anthropogenic fragmentation of habitat disrupts ecological processes and is an on-going threat to species persistence across taxa. River ecosystems are particularly vulnerable to disruptions in connectivity and are the focus of extensive restoration efforts and financial investment. For example, over $300 million/year is invested towards restoration in the Columbia River basin. However, restoration is often impeded by knowledge gaps in distribution that can result in omitting locations that would benefit from restoration. For mobile species within dendritic freshwater networks, the boundary that demarcates the total quantity of available habitat can be defined by the upper limit of occurrence (ULO) and is a useful metric for assessing the extent of habitat to consider for restoration. The first goal of this work was to identify the ULO boundary for three socially and ecologically important anadromous fishes (Oncorhynchus spp.) in a subset of representative streams across a complex river network in southwestern Washington State, USA, and quantify the relationship of the ULO with landscape attributes for these species. Extensive field surveys covering 669 river km across two years documented the ULO in 115 terminal streams (i.e., uppermost independent stream segment within a stream network) for coho salmon (O. kisutch), 97 terminal streams for steelhead trout (O. mykiss), and 57 terminal streams for chum salmon (O. keta). The landscape attributes associated with these ULO locations varied among species. For example, precipitation was an important predictor only for coho salmon, whereas slope was an important predictor only for steelhead trout. In contrast, drainage area, elevation, and geology were important predictors for all species; while the direction was the same for drainage area and elevation, the magnitude of the effect of each landscape attribute varied among species. I demonstrated that large-scale landscape attributes can accurately and consistently detect species-specific distribution boundaries across broad and diverse habitat (percent correct classification:78%-89%; area under the receiver operating characteristic curve: 0.87-0.96). The ability to quantify landscape attributes related to distribution boundaries illuminates how the biology and life history of a species is captured across the landscape. The second goal of this work was to predict the range of occurrence as a function of landscape attributes for coho salmon, steelhead trout, and chum salmon across a range of probability decision thresholds, that reflect different risk-tolerance scenarios and determine whether stream reaches are within or outside the range of occurrence. Generalized linear mixed models were used to compare the quantity of currently described distribution used in restoration planning in the basin and quantify the amount of habitat inaccessible due to anthropogenic barriers. The change in amount of habitat within the predicted range of occurrence across probability decision thresholds ranged from 60%-74% among species. Differences between the model predictions and the currently described distribution for each species ranged from -14% to 171%, which on a whole indicates that the amount of habitat being considered for restoration is currently underestimated. As predicted, species with a greater range of occurrence (e.g., coho salmon) had a greater percentage of predicted suitable habitat inaccessible due to anthropogenic barriers (coho salmon:17.4%-28.8%, 0.75-0.25 PDT; steelhead trout:10.2%-17.5%; chum salmon: 3.9%-12.3%), and the locations of these barriers varied among species. Modelling species distributions at multiple levels of risk-tolerance allows practitioners to weigh the ecological benefits and financial investment when considering locations for restoration. Ultimately, the effective consideration of restoration actions requires tools such that managers can weigh the trade-offs of their decisions given that not all actions equitably benefit all species.
    • Sea otter diet composition with respect to recolonization, life history, and season in southern Southeast Alaska

      LaRoche, Nicole; Pearson, Heidi C.; Eckert, Ginny L.; Miller, Todd (2020-12)
      Until translocation efforts in the 1960s, sea otters (Enhydra lutris) were absent from Southeast Alaska due to extirpation by the fur trade in the 18th and 19th centuries. About 400 sea otters were reintroduced to six Southeast Alaska locations, including two sites near Prince of Wales Island in southern Southeast Alaska. The most recent US Fish and Wildlife Service population count, completed in 2012, estimated that about 25,000 sea otters inhabited Southeast Alaska. Sea otters will reduce invertebrate prey biomass when recolonizing an area. By quantifying sea otter diets and caloric intake according to recolonization patterns, we can better understand the ecosystem impacts of sea otter population increase and range expansion. The goal of this study was to quantify changes in seasonal diet composition and assess the energetic quality of sea otter prey in southern Southeast Alaska. I made visual foraging observations of 3,385 sea otter dives around Prince of Wales Island (POW) to determine diet composition during the spring and summer months. I then collected vibrissae from 45 sea otters obtained from subsistence hunters to assess year-round sea otter diets using stable isotopes. I collected sea otter prey items throughout POW in three seasons (May 2018, August 2018, and February 2019) to measure energy, lipid and protein content, and delta¹³C (carbon) and delta¹⁵N (nitrogen) values. Sea otter diets mainly consisted of clams, as quantified both from visual observations and stable isotope analysis. However, there was more variation in the diet estimates from stable isotope analysis. Stable isotope analysis revealed variation among individual diets of sea otters and individuality in diet within the POW region of sea otters. Sea otters seasonally increased consumption of some prey when the prey was highest in lipid and overall caloric content. Sea otters switched prey types when the prey was more energetically valuable. The results of this study will aid in future management of shellfisheries, subsistence hunting, and implementing co-management of a protected species by providing quantitative diet composition data for stakeholders. This work is a part of a large-scale project examining how the recovery of sea otters structures nearshore marine ecosystems, provides ecosystem services, and affects community sustainability.
    • Sea otters in Southeast Alaska: subsistence harvest and ecological effects in seagrass communities

      Raymond, Wendel W.; Eckert, Ginny L.; Beaudreau, Anne H.; Galloway, Aaron W.E.; Mueter, Franz J. (2020-08)
      The recovery of sea otters (Enhydra lutris) to Southeast Alaska is a conservation success story, but their increasing population raises questions about sea otter population dynamics and the ecological role of this top-level predator. In Chapter 1, we addressed these questions by investigating patterns and population effects of subsistence sea otter harvest. Subsistence harvest reduced populations at a small scale, with potential to slow or stop population growth, but across Southeast Alaska the population continues to grow, even with an average 3% subsistence harvest rate. In Chapters 2 and 3 we investigated the ecological role of sea otters in seagrass (Zostera marina) communities. When we tested for generality in a sea otter - seagrass trophic cascade across a large spatial scale in Southeast Alaska, we found a positive relationship between sea otters and seagrass. However, we found no evidence of a relationship between crabs and epifauna, suggesting that the ecological mechanisms in Southeast Alaska may differ from other regions. Our comparison of carbon and nitrogen stable isotopes (SI) to assess the role of sea otters on trophic structure and energetic pathways of seagrass beds found little effect of sea otters in overall community trophic niche space, suggesting similar carbon sources and food chain length in seagrass meadows regardless of sea otters. Conversely, the FA profiles of diverse consumer suggest variation in dietary sources with and without sea otters. This result suggests that the trophic cascade may not be the only or primary energetic pathway in Southeast Alaska seagrass communities. In all, our studies have revealed that sea otters in Southeast Alaska are linked to both people and a common Southeast Alaska nearshore habitat, seagrass. These results describe the varied interactions of a recovering top predator and highlight a need to consider these diverse interactions in resource management, conservation, and ecological research.
    • Sea urchin ecology: effects of food-web modification, climate change, and community structure

      Weitzman, Benjamin P.; Esler, Daniel; Konar, Brenda H.; Hardy, Sarah M.; Johnson, Mark A.; Tinker, Martin T. (2020-08)
      Ecosystem structure and function of temperate rocky reef habitats are subject to change as a result of food-web modification, climate change, and changes in biological community interactions. Sea urchins are a global driver of change in nearshore marine habitats though their ability to heavily graze marine vegetation and force rocky reef ecosystems from kelp forest to sea urchin barren ground states. The Aleutian Archipelago in southwest Alaska provided an ideal natural laboratory to study sea urchin (Strongylocentrotus spp.) ecology following the functional loss of the keystone predator, the sea otter (Enhydra lutris) during the 1990s. The objectives of this dissertation were to 1) determine the important drivers of sea urchin demographics following the functional loss of their keystone predator; 2) determine how projected ocean warming and acidification may affect sea urchin physical condition; and 3) identify biological drivers of sea urchin recruitment in both kelp forest and barren ground habitats. To determine demographic drivers, I used a time series of benthic habitat, sea urchin demographic, and environmental data, dating back almost forty years. In the absence of sea otters, environmental conditions, specifically ocean temperatures, became more important to sea urchin demographics, but recruitment was the primary process affecting the resultant abundance and size class structure over time. To understand how predicted ocean warming and acidification could impact S. polyacanthus survival, growth, calcification, gonad development, and energy content, a 108-day laboratory experiment was conducted. This experiment determined that temperature caused a greater reduction in survival than acidification, and that projected changes in temperature and acidification will result in investment trade-offs between reproduction and maintenance or growth of somatic and calcified tissues. To determine how recruitment varied between kelp forest and sea urchin habitats, fine-scale surveys of benthic community structure found that specific taxa, and not overall community structure, correlated with sea urchin recruitment. Results from this dissertation will allow managers to make predictions about how sea urchin demography will change as a result of keystone predator loss and climate change and how that will affect nearshore community structure and function. Overall, my dissertation establishes likely pathways by which coastal habitats may change over time, in a system no longer under strong top-down control.
    • Searching the soil: characterizing the effects of disturbance on soil microbial communities and plant productivity

      Seitz, Taylor J.; Drown, Devin M.; Mulder, Christa; Briggs, Brandon (2021-08)
      The effects of global climate change are accelerated and more pronounced in northern regions, and Alaska is at the forefront of that change. Permafrost, which underlies much of the Alaskan landscape, is rapidly thawing and degrading leading to shifts in hydrology, soil chemistry, and nutrient availability. As permafrost thaws, soil microbial communities have the potential to be influenced taxonomically and functionally. However, it is unclear how active layer microbial communities, which play a role in plant-microbe interactions, are affected by increasing soil disturbance, and how soil microbiomes can influence above ground plant communities. In this study, I aimed to understand how soil microbial communities from Interior Alaska are affected by increasing disturbance, and how they in turn drive the productivity of several plants found in boreal regions. Here I used a growth experiment and found that plant productivity was affected by the disturbance level of the microbial inoculant. Plants grown in soils inoculated with microbes associated with disturbed soils demonstrated significantly decreased productivity compared to plants inoculated with microbes from undisturbed soils. Through metagenomic sequencing, I observed broad scale shifts in community membership across the gradient of soil disturbance. I then continued to characterize the microbial communities used as inoculants in the greenhouse growth experiment through 16S rRNA amplicon sequencing. Microbial communities from disturbed soils were significantly more diverse than those from undisturbed soils, and the beta diversity of communities varied significantly based on the disturbance level. We found that within disturbance level community variation can be used to predict plant growth of bog blueberry, low-bush cranberry, and Labrador tea once the disturbance passes a threshold. These results suggest that as active layer microbial communities are affected by climate-driven soil disturbance, above ground plant communities may demonstrate decreased productivity, and consequently, decreased ecosystem health as the Arctic continues to warm.
    • Seasonal variation in nutritional biomarkers and fecal cortisol concentrations in a northern population of snowshoe hares

      Montgomerie, Claire Kornet; Kielland, Knut; Breed, Greg; Lian, Marianne (2020-08)
      Blood biomarkers indicative of nutritional status, fecal cortisol metabolite concentrations and an established body condition index (BCI), were collectively examined from snowshoe hares(Lepus americanus) inhabiting northern Alaska in 2018, during five ecologically significant times of year. As a novel approach to increase our understanding of the effects of diet and predation pressure on hare physiology, I addressed how these markers were associated with seasonal timing of energetic demands and adult survival rates. Mean decreases in concentrations of total protein (TP), blood urea nitrogen (BUN), hematocrit (HCT) and glucose during spring and autumn, suggest that snowshoe hare nutritional status decreased during these two seasons in 2018. The shoulder seasons of spring and autumn coincide with energetic challenges, including molt, changes in diet and breeding. Because available forage during these seasons largely consists of winter-dormant twigs, the energy expenditure of growing a new winter coat (autumn) and breeding behavior (spring) may compromise the energy balance of hares during these periods. Male hares, whose activity levels increase during breeding, exhibited lower BCI scores and were slower to molt from white to brown than female hares in May. Furthermore, adult survival rates were lowest during spring months. Snowshoe hare mean fecal cortisol metabolite concentrations did not show associations with seasons of apparent low nutritional status. Adult hare survival rates peaked during summer and early autumn, during which mean values of TP, BUN, Hct, Cl (chloride), Na (sodium) and glucose also increased. By contrast, this period coincided with a 2-fold increase in mean fecal cortisol metabolite concentrations, suggesting that the apparent stressor was not related to nutrition. Interestingly, after having decreased in autumn, BUN, Hct, TP, and glucose mean concentrations increased in midwinter. Free calcium (iCa) and potassium (K) mean concentrations were also highest in December. Hares may have reduced activity during winter months, and metabolic rates may have increased to cope with thermoregulation demands. BCI scores decreased by December, suggesting use of endogenous reserves. Lowest seasonal mean cortisol metabolite concentrations were also observed in mid-winter. This study demonstrates the value of examining both physiological and morphological metrics of snowshoe hare condition to better our understanding of how seasonal trends in food and fear may unfold into cyclic patterns.
    • A sled dog model for positive health effects of weight management and exercise

      Falkenstein, Laura Kay; Dunlap, Kriya; Coker, Robert; Jerome, Scott (2021-08)
      Hypertrophic white adipose tissue found in obesity leads to chronic inflammation and reduced insulin sensitivity, bringing rise to a myriad of diseases and is a significant risk factor for premature death. Obesity can be combatted with physical activity, dietary restrictions, or a combination of the two. However, exercise training regardless of changes in body weight has been shown to improve metabolic health. Expanding on a previous study of changes in metabolic biomarkers upon weight gain and after a period of athletic conditioning, in this project we used a sled dog model to examine biomarker shifts over a course of sedentary weight gain, exercise training without weight loss, and exercise training accompanied by weight loss. In order to examine the benefits of exercise training both with and without weight loss, a cohort of healthy sled dogs each served as their own controls as we observed changes in metabolic indices in conjunction with moderate body weight gain, exercise training while sustaining the higher body weight, and exercise training with weight loss.We focused on indices specifically linked to type II diabetes - an obesity-linked disease affecting more than 10% of American adults. Biomarkers measured include plasma glucose, glucose transporter 4, insulin, and hemoglobin A1c. We also measured inflammatory cytokines tumor necrosis factor alpha and interleukin 6, as well as hormones leptin, adiponectin, and resistin. Many biomarkers measured produced not significant change or fell outside of our standard concentrations, but plasma glucose, glucose transporter 4, and tumor necrosis factor alpha produced intriguing results. Weight gain increased plasma glucose while exercise training increased glucose transporter 4 present on peripheral blood mononuclear cells. The changes we observed to plasma glucose, glucose transporter 4 and tumor necrosis factor alpha may be indicative of reduced insulin sensitivity with exercise and weight loss. We believe this may be the result of the high energy demand of exercise training coupled with low caloric availability.
    • Sled dogs as a model for studying dietary vitamin D

      Striker, Kali; Dunlap, Kriya; Jerome, Scott; Drew, Kelly (2021-05)
      Vitamin D deficiency (VDD) has become a pandemic and has shown to be correlated with several poor health outcomes. Many factors that lead to VDD are environmental and lifestyle. Vitamin D has physiological implications involved in all areas of human health and is also important for animal health. Canines have shown adverse health outcomes similar to humans that correlate with vitamin D deficiency such as chronic kidney disease (CKD) and irritable bowel disease (IBD). Canine vitamin D requirements are largely unknown due to the lack of research and the wide ranges of supplementation throughout dog food manufacturers. Pre-active plasma vitamin D metabolites are used as the biomarker of vitamin D status in humans and dogs but may not be representative of overall vitamin D status. Therefore, other biomarkers representing vitamin D status are often used in conjunction to determine physiological relevance. To address this gap in knowledge, this study used parathyroid hormone concentrations as well as vitamin D binding protein concentrations to establish more of an overall status of vitamin D. In canines, clinical supplementation following VDD is usually administered orally with vitamin D olive oil tablets; however, supplementation is usually unsuccessful. Vitamin D and its metabolites are lipid soluble and stored in adipose tissue. Although few foods provide appreciable levels of vitamin D, wild salmon contain some of the highest dietary vitamin D levels. People living in Alaska are at an increased risk of VDD due to reduced zenith sun angles for much of the year. Consequentially sufficient vitamin D levels need to be acquired through diet or supplementation. Historically, Alaska Natives obtained sufficient amounts of vitamin D from traditional subsistence foods, but with the progressive shift away from these foods VDD has increased in Alaskan populations. The limited research available suggests that Alaskan sled dogs in particular are a group found to be generally VDD. Sled dogs are an important part of the traditional Alaska subsistence lifestyle and have evolved alongside humans in the circumpolar north. Sled dogs, therefore, provide a valuable model for studying health outcomes associated with VDD in both people and dogs in the far north. This study provides significant evidence showing wild Alaskan salmon as a dietary source of supplementation to raise 25(OH)Vitamin D serum in dogs after only 4 weeks. We also show significance in variation by confounding factors, age and sex.
    • The sound of 1001 indigenous drums: the catalytic cycle of Fire Eagle, Golden Eagle, Thunderbird

      Marsden, Davita Aphrodite-Lee; Topkok, Sean Asiqłuq; Smith, Graham Hingangaroa; John, Theresa; Leddy, Shannon (2021-05)
      I have witnessed Indigenous students experience marginalization, being ignored, being labelled, and earning developmental designations, all as a way to continue systemically oppressing them. Indigenous students traditionally did not sit in rows, they did not compete for the highest mark, an A+ or a B. Indigenous education and learning is a process, and no one fails. Systemic oppression continues in public education where Indigenous students are alienated, being pushed out, kicked out, or continuously transferred from school to school. After fasting for 1,000 days, I received a vision of how to move Indigenous education forward: I began making Indigenous drums; I taught singing to students, staff, and admin. Reinstatement of Indigenous culture such as drumming and singing increases self-esteem, self-identity, confidence, and self-determination for the learner and is a tool for healing intergenerational trauma. These cultural supports, therefore, become critical for the success of Indigenous students and they are helping Indigenous education and people move forward without fear. There is a hegemonic imbalance of power and we need a reallocation of government funds in public education. Indigenous students have the right to attend school and participate without penalty, punishment, or humiliation. Swept under the school "welcome mat" are all forms of racism in public education. Critical Indigenous theory considers unequal power relations as they affect urban Indigenous students. The imbalance creates marginalization and prejudices towards Indigenous students. This dissertation uses retrospective study on the students' Artwork Stories, a free expression that allows specific elements and past patterns to emerge and reveal that Indigenous drumming and singing correlates to specific values and emotions. The spirit of Indigenous iv drumming and singing gives the student a visual voice in research through the Artwork Story documents. The Gichi'ayaag (Elders) say the Medicine Wheel has many teachings, as many as there are grains of sand in this world. The Complex Medicine Wheel Model shapeshifts into the Medicine Wheel Colour Knowledge Chart analytical model, providing a research tool that analyzes students' Artwork Stories experience. The sound of the Indigenous drum will ripple around the world and continue its transformation one beat at a time. Our unceded territories are calling back languages and the spirits of the land to further Indigenous education. This drum's voice bridges those of the Ancestors, the women, and our spirits. When you hear the sound of an Indigenous drum in your school, you will know we bring change, a change that you cannot stop, nor would you want to. The analysis of Indigenous drumming and singing aligns with evidence-based approaches and the quantification of learning. There is an urgent need to Indigenize K-12 curriculum by incorporating Indigenous drumming and singing into their classrooms. Those who promote Indigenous pedagogy and culture have just begun to Indigenize the education of Indigenous peoples into mainstream public education. Now is the time when Indigenous education and culture are on the rise and can be recognized as paramount for Indigenous student success. This research will benefit all learners in public education.
    • Sources and effects of strontium in waterfowl eggs

      Latty, Christopher J.; Hollmén, Tuula E.; Matz, Angela C.; Powell, Abby N.; Hobson, Keith A.; Adkison, Milo D. (2021-05)
      Strontium (Sr) may be a contaminant of concern for wild birds. Because of chemical similarities to calcium (Ca), Sr is readily incorporated into calcified tissues, such as eggshells. My objectives were to determine the potential drivers of both total and radio-Sr in the eggshells of waterfowl, and to assess the relationship between eggshell Sr and thickness. I collected eggs from sympatrically nesting waterfowl species in interior Alaska from 2011-2013. I measured total and radio-Sr in eggshells, environmental chemistry, and eggshell thickness. Local water chemistry explained much of the variation in eggshell Sr for canvasback (Aythya valisineria) and northern shoveler (Spatula clypeata), but not lesser scaup (Aythya affinis). Most of the remaining variation was associated with heterogeneity among eggs in the same nest (intra-clutch variance). General trends in eggshell Sr/Ca among species aligned with what would be expected had diet and/or endogenous reserve use affected eggshell chemistry. Results were similar for radio-Sr, with local water chemistry accounting for far less ⁹⁰Sr in the eggshells of lesser scaup, compared to the other species studied. At the site where water chemistry was stable, canvasback and northern shoveler eggshell thickness was not related to eggshell Sr, but lesser scaup eggshells with more Sr were thicker. At the site where water chemistry was variable, canvasback and northern shoveler eggshells with more Sr were thicker at low to intermediate concentrations, but this effect was moderated when the source of eggshell Sr appeared to be explained by the local environment. In contrast, lesser scaup eggshells with more Sr were consistently thicker, but only at higher concentrations. The different relationships between eggshell Sr and thickness across species, and interactions with apparent Sr sources, suggest the relationship between eggshell thickness and Sr is not a simple dose-dependence. My results show that for some species like lesser scaup, factors associated with the laying hen (e.g., diet or physiology) may have a larger impact on both eggshell total and radio-Sr, as well as how Sr interacts with eggshell quality, than the local environment.
    • Sowing change through the elderly herbalist: The country of the pointed firs (1896) and Rosemary's baby (1968)

      Corty, Cheyenne Alexis; Schell, Jennifer; Harney, Eileen; Johnson, Sara (2020-12)
      This thesis focuses on Sarah Orne Jewett and Roman Polanski's elderly herbalists as reactionary tropes to feminist movements in either era. Jewett creates elderly herbalist and town scholar, Almira Todd in Country of the Pointed Firs (1896), and Polanski personifies author Ira Levin's Satanist cult member Minnie Castevet (Ruth Gordon) in his film Rosemary's Baby (1969). Jewett's Almira Todd focuses on the positives and negatives inherent within her profession--holistic healer and town matriarch--placing her in the role of the benevolent herbalist. Polanski's Minnie Castevet, in contrast, presents a malevolent herbalist, one who seeks to harm the title character of the film. Both characters exist within the height of the feminist movements of either era and by being elderly herbalists, each character acts as a response or reaction to the movements via the trope.
    • Spatial and temporal variability of dissolved aluminum and manganese in surface waters of the northern Gulf of Alaska

      Kandel, Anna R.Y.; Aguilar-Islas, Ana; Danielson, Seth; Hennon, Gwenn (2020-12)
      The Northern Gulf of Alaska (NGA) shelf is a productive high-latitude environment where nutrient dynamics are greatly impacted by the seasonal variability in freshwater input and water column mixing. Iron is a key nutrient on the NGA shelf that directly modulates primary production, but inputs are difficult to quantify due to high biological uptake and control exerted by Fe-binding organic ligands. Other lithogenic elements such as aluminum and manganese have the same sources as iron (rivers and sediment) and similar abiotic removal via particle scavenging, but exhibit quasi- conservative behavior in seawater allowing for their use as tracers of these sources. Thus, Al and Mn distributions can help provide insight into iron inputs and the relative importance of various mechanisms influencing nutrient dynamics in the NGA. The data are derived from spring, summer, and fall NGA LTER (long term ecological research) cruises from 2018 and 2019 that included a focused five-day Copper River plume study, several surface transects from Kayak Island to Kodiak Island, and vertical profiles at several locations sparsely distributed throughout the shelf. We find that seasonal patterns in the surface concentrations of dMn and dAl mirrored annual glacial melt cycles, with the lowest values observed in spring and higher values in summer and fall. Spatial patterns were also apparent as both metals tended to be lower offshore than inshore, and were also lower overall (by 1-2 orders of magnitude) on transects further from the outflow of the Copper River, a major source of freshwater to the NGA. Extremely high concentrations in the Copper River plume (≤1395 nM dAl, ≤128 nM dMn) and strong correlations with salinity (p < 0.0001) highlight their quasi-conservative nature, and their usefulness as tracers of freshwater input, which helps inform iron inputs from this source. Enhanced dAl and dMn concentrations within nepheloid layers in subsurface waters indicate regions where a sedimentary source of iron is likely to be important. Residence times for dAl and dMn in surface waters over the NGA shelf were estimated to be 31 days (dAl) and 42 days (dMn) on average based on summer and fall data from both years.
    • Spatio-temporal genetic structure, effective population size, and parentage simulations from contemporary genetic samples and historic demographic data of sockeye salmon (Oncorhynchus nerka) in Auke Lake, Alaska

      Barry, Patrick D.; Gharrett, Anthony; McPhee, Megan; Anderson, Eric; Tallmon, David (2021-08)
      Pacific salmon (Oncorhynchus spp.) have great ecological, economic, and cultural importance. Accordingly, understanding the genetic diversity of Pacific salmon populations is critical for their effective management and conservation. Spatial and temporal homing fidelity, a central life-history characteristic of Pacific salmon, generates genetic structure through reproductive isolation. Within and among populations, heterogeneity in the freshwater environment should lead to selection for traits that maximize fitness resulting in local adaptation. This adaptation increases productivity of individual populations while diversity among populations can promote long-term stability. Additionally, the demographic properties (age structure, generation length, size) of a population will affect genetic structure by regulating its response to the evolutionary forces of selection, migration, and genetic drift. The scale and extent to which reproductive isolation can produce genetic structure is incompletely understood. In this dissertation, I investigated spatial and temporal trends in population genetic structure and estimated the effective population size (Ne) of Sockeye Salmon from Auke Lake in Southeast Alaska from contemporary genetic samples (2008, 2009, 2011) and historic demographic data (1980-2017). A simulation library in the R statistical environment was developed to assess the accuracy of parentage and sibship inference from genetic markers. This library proved useful in evaluating the sibship method for estimating Ne from genetic data and evaluating genetic markers for a large-scale parentage project. I detected substantial genetic differentiation between Auke Lake and other Southeast Alaska populations (average FST = 0.1137) and an isolation-by-time pattern within the Auke Lake population. A genetically distinct cluster was identified in the late portion of the 2008 return. This group may represent a spatially segregated spawning aggregation previously described in tagging studies; however, because fish were sampled as they passed through the weir, spatial structure within Auke Lake could not be evaluated. Genetic tests for demographic change within the population indicated that the Auke Lake Sockeye Salmon population underwent a historical bottleneck event but has since increased in size. Demographic estimates of Ne from a long-term dataset from the Auke Creek weir revealed that the effective population size was low in the early 1980s and has since increased. Over the six generations evaluated, the major demographic factors that determined Ne were variance in family size, variable contribution to the next generation by brood years within a generation, and fluctuations in population size. Contemporary estimates of Ne from genetic methods were smaller than those from demographic methods and indicated that Ne may be roughly the size of an individual return year. Genetic estimates of the ratio of the effective population size to the census size (Ne/Nc = 0.21) were consistent with values previously reported for other salmonids. Collectively, these chapters contribute to an improved understanding of Sockeye Salmon population genetics and provide a useful tool to assess the power of genetic markers for parentage and sibship inference.
    • Spawning migration characteristics and ecology of Eulachon (Thaleichthys pacificus)

      Spangler, Robert E.; Norcross, Brenda; Hay, Douglas; López, J. Andres; Seitz, Andrew (2020-12)
      Eulachon Thaleichthys pacificus has experienced dramatic reductions in their distribution and abundance along the west coast of North America. This prompted the listing of this species as "Threatened" under the U.S. Endangered Species Act (ESA) of 1973 for populations found in the southern portions of their range, but not in Alaska. Key gaps in knowledge of Eulachon spawning ecology exist that impede population monitoring efforts and habitat protection. Currently, many monitoring efforts ignore estuaries as possible spawning habitat leading to inaccurate estimates of population abundance and trends. Furthermore, estuaries are not designated as critical spawning habitat for Eulachon. This is important because a critical spawning habitat designation under the ESA provides for a regulatory framework on which to focus conservation and restoration efforts for some of the most imperiled aquatic habitats in North America. I hypothesized that Eulachon spawn in estuaries based on limited observations in other research and the close phylogenetic relationship between Eulachon and other smelts (Osmeridae) that can tolerate salinity. To test this hypothesis, I first studied the effects of salinity on the fertilization and hatching success of Eulachon in a laboratory setting to determine salinity tolerance. Second, I investigated estuary spawning in the Twentymile and Antler rivers, Alaska using radio telemetry and substrate surveys to confirm spawning areas. Third, I examined the relationship between adult spawning run intensity and the environmental variables of tide height, water discharge, and day or night to better inform future population monitoring efforts. My findings in the laboratory indicated that Eulachon can fertilize eggs and produce viable offspring in brackish water. These results were confirmed by egg areas observed in the estuaries of the Twentymile and Antler rivers. Furthermore, spawning run intensity increased in association with spring tides, but there were no clear relationships between spawning run strength and freshwater discharge or day and night. Based on the results of my work, I recommend changes to population monitoring study design and designation of critical spawning habitat to include estuaries. Future research should focus on determining the lower limits of Eulachon spawning habitat to further improve population monitoring and habitat protection.
    • Stable isotope ecology of an Arctic raptor guild

      Johnson, Devin Leland; Williams, Cory; Anderson, David; Booms, Travis; Breed, Greg; O'Brien, Diane (2021-08)
      As top predators in a rapidly changing environment, Arctic raptors serve as indicator species of ecosystem health. The degree to which populations exhibit dietary plasticity and partition resources on an interspecific basis under dynamic ecological conditions may be indicative of climate change resilience. It is therefore crucial to develop accurate and broadly applicable methods for characterizing the diets of wild populations. In this dissertation, I assessed the performance of Bayesian stable isotope mixing models (BSIMMs) as a method of characterizing diet in free-living raptor populations, developed novel methods to refine their accuracy and applicability, and applied an isotopic approach to address broad trophic hypotheses within an Arctic raptor guild. First, I evaluated the use of BSIMMs in a population of Gyrfalcons (Falco rusticolus) by comparing modelled diet estimates to high-accuracy nest camera diet data. I found that the isotopic method effectively characterized diet at the population level and accurately identified temporal shifts in Gyrfalcon diet on a seasonal and interannual basis. Second, I developed a novel method for the estimation of trophic discrimination factors (TDFs) in wild populations and tested it in three published datasets. The new method outperformed other methods of TDF estimation in all cases, ultimately increasing the accuracy and applicability of the BSIMM approach under certain circumstances. Third, I applied an isotopic approach to characterize interspecific niche overlap and individual specialization in an Arctic raptor guild (Gyrfalcons, Golden Eagles [Aquila chrysaetos], and Rough-legged Hawks [Buteo lagopus]) under varying degrees of resource abundance. I found the three species overlap in their isotopic niche, but that overlap was reduced when more prey types were available (i.e., an influx of cyclic arvicoline rodents). In Gyrfalcons, the level of individual specialization increased with increasing population niche width in accordance with the niche variation hypothesis.