• Social organization and spatial relationships in coastal river otters: assessing form and function of social groups, sex-biased dispersal, and gene flow

      Blundell, Gail Marie (2001-05)
      River otters (Lontra canadensis) inhabiting marine environments are top-level predators foraging in the nearshore ecosystem and recently have been recognized as indicators of environmental health. Otters were extirpated from much of their historic distribution because of exposure to pollution and urbanization, resulting in expansive reintroduction programs that continue today. Without an understanding of the influence of factors such as social structure, mating system, or sex-biased dispersal on genetic variation and gene flow among populations, effects of local extirpation and the potential for natural recolonization (i.e., the need for reintroductions) cannot be determined. The objective of this study was to assess social organization and evaluate the importance of factors such as prey availability and kinship on formation of social groups and dispersal of individuals. Fifty-five otters were radio-tracked in three study areas in Prince William Sound, Alaska, from 1996 to 1999, to determine social organization and dispersal rates. Data from 111 individual otters (seven study areas) were obtained to assess relatedness and gene flow (with microsatellite DNA) and diet (with stable isotope analysis of ð¹³C and ð¹⁵N). DNA analysis indicated that kinship had no effect on social organization or spatial relationships among otters. Analyses of diet and home-range size indicated that social groups may be formed to facilitate cooperative foraging, enabling social otters to obtain a better-quality diet more efficiently (i.e., social otters had diets higher in schooling pelagic fishes and had smaller home ranges, compared to nonsocial otters). Male otters were more social than females, but reproductive constraints likely limited opportunities for sociality among females. Both telemetry and genetic data indicated that male and female otters had an equal, low probability of natal dispersal and male otters also exhibited breeding dispersal resulting in gene flow to nearby populations. Genetic data indicated distances for natal dispersal were bimodal; most males and some females settled nearby (within 16-30 km), but some females dispersed 60-90 km. Despite lack of geographic barriers to dispersal in a marine system, dispersal distances were relatively short, indicating that extirpation of local populations would be difficult to correct via natural recolonization unless viable otter populations were available nearby.
    • Some aspects in the ecology of the black bear (Ursus Americanus) in interior Alaska

      Hatler, David F. (1967-05)
      Research during 1964 and 1965 revealed that black bears in interior Alaska are active only 5 to 5.5 months each year. Emerging from winter dens in early May, the animals spend most of the first 3 months in river bottom and other lowland situations where green vegetation, especially Equisetum spp., composes the bulk of their diet. From the last half of July until mid-September bears are observed most commonly in alpine areas where fruits, especially Vaccinium uliginosum, are the important food. Animal food, constituting less than 15 percent (volume) of the animal's diet, is apparently taken whenever it is obtainable. Most animal food occurrences involve insects. Litter size averaged 1.73 for 30 litters observed during the 2 years studied. Litters larger than two do not seem to be common in interior Alaska. Intestinal parasites were found in 12 of 16 bears. Two heavy infestations of ascarids, 249 worms in one bear and 53 in another, were observed. Serious predation by interior Alaskan black bears upon the nests of some waterfowl has been recorded; predation upon most other wildlife species appears to be negligible. Evidence gathered during this study suggests that the rash of black bear problems experienced by interior Alaskans in 1963 was due largely to the widespread lack of blueberries during that year.
    • Spatial scales of muskox resource selection in late winter

      Wilson, Kenneth J. (1992-05)
      I examined resource selection by muskoxen in late winter on the coastal plain of the Arctic National Wildlife Refuge, Alaska, by comparing use and availability at regional, meso, local, and micro spatial scales. Use of vegetation types for feeding appears to be based on selection of areas of shallow soft snow with high cover of sedges, dead vegetation, and total vegetation, and on selection against areas of little vegetation cover or deep hardpacked snow. Muskoxen used moist sedge, tussock sedge, and Dryas terrace tundra in proportion to availability and avoided barren ground, partially vegetated, riparian shrub, and Dryas ridge tundra. Selection for areas of shallow snow occurred within vegetation types as well as between vegetation types. Occurrence of sedges and grasses in the diet was greater than availability. Feeding zones were primarily on windblown vegetated bluffs; these areas are distributed in narrow bands along creeks, rivers, and the coastline.
    • Species distribution models for Denali National Park and Preserve, Alaska

      Ritter, Joy L. (2007-05)
      The objective of this study is to explore the use of existing data to model the distribution of four species in Denali National Park; caribou, moose, grizzly bear, and wolf. Radiolocation data consisting of 1331 locations collected over three years for female caribou, 1329 locations collected over three years for female moose, 6579 locations collected over ten years for grizzly bears, and 2686 locations collected over three years for wolves were obtained from park biologists. A geographic information system was used to derive landscape characteristics associated with the animal locations and random locations placed in the same area. Caribou models were developed at three spatial scales with three different algorithms. Classification tree models showed a high prediction success, correctly classifying 75 to 94 percent of randomly withheld animal locations. Fall models for female caribou had the poorest prediction ability while summer models for female grizzly bears performed best. Topographic landscape characteristics such as elevation and terrain ruggedness were important classifiers for most of my prediction models. Distribution maps were developed for individual and multiple species during different seasons. Areas of moderate elevation along the north side of the Alaska Range are important for all our study animals.
    • Stopover ecology of semipalmated sandpipers (Calidris pusilla) at coastal deltas of the Beaufort Sea, Alaska

      Churchwell, Roy Thomas; Powell, Abby; Gens, Rudiger; Dunton, Kenneth; Blanchard, Arny; Hundertmark, Kris; Hollmen, Tuula (2015-12)
      Avian migration is one of the wonders of the natural world. Stored fats are the main source of nutrients and fuel for avian migration and it is assumed the fat deposition at stopover sites is a critical component of a successful migration. Stopover sites are crucial in the successful migration of many birds, but particularly for arctic-breeding shorebirds that migrate long distances from breeding to wintering grounds. Despite the importance of stopover sites, it is often difficult to determine the importance of these sites to migrating shorebirds. I investigated three aspects of stopover ecology of Semipalmated Sandpipers (Calidris pusilla) foraging at coastal deltas on the Beaufort Sea coast, Alaska. First, I quantified the spatial and temporal distribution and abundance of the benthic macroinvertebrate community living within the mudflats. I found that there were two ecological groups of macroinvertebrates using river deltas, one originated in terrestrial freshwater habitats and most importantly could withstand freezing in delta sediments over the winter, and the other originated from the marine environment, could not withstand freezing and had to migrate to intertidal habitats each summer from deeper water areas that did not freeze over the winter. Stable isotope analysis allowed me to describe the origin of carbon consumed by invertebrates in intertidal habitats. I predicted freshwater invertebrates would consume terrestrial carbon, and marine invertebrates would consume marine carbon, but I found that both groups utilized the same carbon, which was a mixture of terrestrial and marine sources. My second research question determined the importance of delta foraging habitat for fall migrating Semipalmated Sandpipers. I mapped the temporal distribution and abundance of birds and quantified this relationship to invertebrate distribution and abundance. I researched fattening rates of shorebirds by measuring triglycerides in the blood of shorebirds I captured. I hypothesized that triglyceride levels would be correlated with invertebrate abundance and related to habitat quality; however, I found no relationship. Next, I determined shorebird dependence on marine invertebrates using the stable isotope signature of invertebrates and shorebird plasma. I found that shorebird abundance was associated with invertebrate abundance, and that shorebirds did feed almost exclusively on invertebrates from the mudflats later in the season. I did not find a significant difference in habitat quality among the deltas, although more birds were counted at the Jago Delta than at the other two deltas. Finally, I researched the question of how change in water levels due to lunar tides and storm surge events impacted the availability of foraging habitat. I assessed the phenology of Semipalmated Sandpiper migration and how this related to the availability of forage based on abundance, distribution, and accessibility of macroinvertebrates. There was a significant decline in the calories available for forage when there was a lunar tide and when there was a storm surge event. The most foraging habitat was available late in the migration period, while the peak in Semipalmated Sandpiper migration was early in the period. Late in the season there is also a greater chance of a storm surge event occurring due to the lack of sea ice during that period. In summary, I found Beaufort Sea deltas were more diverse than I expected both in macroinvertebrate community and in how shorebirds use the available foraging habitat. After completing this research I feel this habitat is critical to Semipalmated Sandpiper migration; however, there is a real risk of extensive change to these deltas due to future warming with negative consequences for shorebirds.
    • Successional changes in the hydrology, water quality, primary production, and growth of juvenile Arctic grayling of blocked Tanana River sloughs, Alaska

      Wuttig, Klaus G. (1997-08)
      A comparative stream study was conducted to assess the influence of development and blockage on the hydrology, water quality, primary production, and Arctic grayling of Badger Slough, Alaska. Data collected showed that Badger Slough exhibited stable, clear flows throughout the summer, and higher total and total dissolved phosphorus, orthophosphate, alkalinity, pH, conductivity, and average temperatures, and lower winter dissolved oxygen concentrations than both Piledriver and 23-Mile Sloughs. Mean algal biomass (3.3 mg m-3) and primary production (6.9 g O2 m-2 d-1) are greater than that recorded for any other interior Alaska streams and percent fines in riffle substrates have increased. However, growth of age-0 grayling remains high. Badger Slough has eutrophied due to increased nutrients and stable flows, and the quality of rearing habitat for age-0 fish remains good. However, an annual flushing flow of 8.0 m3 s-1 is recommended for controlling accumulations of fines and maintenance of grayling habitat.
    • Summer ecology of the Teshekpuk caribou herd

      Parrett, Lincoln Scott (2007-05)
      The summer range of the Teshekpuk Caribou (Rangifer tarandus granti) Herd is currently undergoing the initial stages of petroleum exploration and development. Pre-development baseline information is necessary to interpret post-development distribution and habitat selection of caribou and to develop mitigation measures. We estimated bi-weekly distributions, diet and habitat selection by caribou during the summers, 2002-2004, based on aerial relocations of 21-49 radio-collared females. Little or no habitat selection was detected when comparing used locations to habitat available within bi-weekly utilization distributions. Habitat selection was much stronger when comparing bi-weekly utilization distributions to the remaining area of summer use. At the latter scale of analysis, there were dynamic temporal patterns in resource selection by caribou. High air temperature was strongly avoided throughout July. Tussock tundra was avoided early in the summer, but selected during August. Wet sedge was selected in June and from late-August through September. Estimates of dietary nitrogen content indicated that high nitrogen concentrations are available only for a short period in early summer, and declined well before forage biomass. Predicted dietary nitrogen concentration appeared to be much lower for the Teshekpuk Caribou Herd than for the Porcupine Caribou Herd. Successful mitigation measures for petroleum development in NPR-A will need to be spatially and temporally tailored to observed dynamic patterns in caribou resource selection. Future work should estimate the performance of caribou (e.g., survival or weight gain) in relation to habitat quality and use in order to confirm the value of selected habitats and to enhance the robustness of mitigation measures.
    • TEST College of Engineering & Mines 9/25/17

      CHISUM (2017-09)
      TEST College of Engineering & Mines 9/25/17
    • The Ecology Of Marten In Southcentral Alaska

      Buskirk, Steven William (1983)
      The ecology of marten in the upper Susitna Basin, southcentral Alaska was studied from January 1980 to June 1982. Data were gathered on home range and movements, seasonal food habits, habitat use and winter energetic strategies. Radio telemetry was used to obtain a total of 560 locations for 17 marten. Mean home range sizes of marten along the Susitna River were 3.71 km('2) for females, 6.82 km('2) for males and 6.75 km('2) for adult males (2+ years). Marten were found to be nocturnal in autumn and to show strong variability in their diel activity patterns in late winter. Marten tended to move upward in elevation during spring and downward in autumn, contrary to the prevailing views of trappers. Analyses of marten scats and colon contents collected during four seasons showed the most important foods to be microtine rodents, squirrels, fruits and birds. Major foods showed strong seasonal variation in utilization. Microtines were most important in autumn and showed declining use over winter. Northern red-backed voles were the most important microtine species. Sciurids were most important in spring and appeared to be a nonpreferred alternative food. Marten made little use of shrews, snowshoe hares, porcupines or insects. Carrion and human foods were highly preferred and consumed when available. Habitat utilization was studied through the use of aerial transects and snow tracking and by identifying resting sites. Marten foraged for microtines more frequently than expected in vegetation types dominated by black spruce. Marten rested in winter primarily in active red squirrel middens in stands dominated by old-growth white spruce. Fat depot and organ weights and total body fat of marten were measured to find an indicator to total body fat. Marten were found to have extremely low body fat ratios which did not show a significant change over winter.
    • The Effects Of Changes In Climate And Other Environmental Factors On Permafrost Evolution

      Jafarov, Elchin; Romanovsky, Vladimir; Layer, Paul; Marchuoko, Sergei; Walsh, John (2013)
      Permafrost is a product of a past colder climate. It underlies most of the terrestrial Arctic, where it influences landscape hydrology, biogeochemical environments and human activity. The current thermal regime of permafrost is mediated by different environmental factors, including snow, topography, vegetation and soil texture. The dependence of permafrost on these factors greatly complicates the modeling of permafrost dynamics. Accurate modeling of these dynamics, however, is critical for evaluating potential impacts of climate change on permafrost stability. The objectives of this study were to a) improve modeling of ground temperature during snow season; b) analyze the effects of post-fire environmental changes on permafrost thermal stability; and c) predict 21st century ground temperature dynamics in Alaska with high spatial resolution. To achieve the proposed objectives, near-surface air and ground temperatures were measured at permafrost observation stations across Alaska. Measured ground temperatures were used to evaluate simulated ground temperatures, which were generated with the Geophysical Institute Permafrost Laboratory (GIPL) numerical transient model. The current version of the GIPL model takes into account climate, snow, soil texture, soil moisture, and the freeze/thaw effect. To better model ground temperatures within the soil column, it was necessary to improve the parameterization of snow layer thermal properties in the GIPL model. To improve ground temperature simulations during snow season, daily snow thermal properties were estimated using an inverse approach. Modeling bias was improved by including ground temperatures simulated using estimated daily snow thermal conductivities. To address the effects of fire disturbance on permafrost thermal stability, we applied the GIPL model to lowland and upland boreal forest permafrost environments. The results indicate that permafrost vulnerability depends on pre-fire organic soil layer thickness and wetness, the amount of organic matter burned during the fire, and post-fire soil organic layer recovery rates. High spatial resolution permafrost maps are necessary for evaluating the potential impacts of permafrost thawing on Arctic ecosystems, engineering facilities, infrastructure, and the remobilization of soil carbon. Simulated ground temperatures in Alaska during the 21st century indicate widespread permafrost degradation in the discontinuous permafrost zone. High ground temperature warming trends are projected for most of the continuous permafrost zone north of the Brooks Range.
    • The Foraging Behavior, Habitat Use, And Diet Of Arctic Foxes (Alopex Lagopus) In A Goose Nesting Area Near Kokechik Bay, Alaska

      Stickney, Alice Allgood; Murphy, Edward C. (1989)
      The foraging behavior, habitat use, and diet of arctic foxes were observed in a goose nesting area near Kokechik Bay, Alaska during the summers of 1985 and 1986. The foraging patterns of arctic foxes changed after birds started nesting in the study area, adding an abundant egg resource to a previously limited prey base. The duration of search bouts decreased and success rate increased, yielding an increased prey capture rate. Over 80% of the eggs taken by foxes during the nesting stage were cached, rather than eaten immediately. Differences in search patterns among foxes were probably related to the different prey available within the range of each fox. Egg caches extended fox access to a temporally clumped resource, and increased the impact of foxes on the nesting success of geese. Eggs were the primary prey of foxes during the nesting stage in both years, regardless of variations in microtine abundance. <p>
    • Thermal limitations on chinook salmon spawning habitat in the northern extent of their range

      Decker, Samantha Kristin Strom; Margraf, F. Joseph; Rosenberger, Amanda; Evenson, Matthew (2010-05)
      Pacific salmon (Oncorhynchus) habitat models attempt to balance research efficiency with management effectiveness, however, model transferability between regions remains elusive. To develop efficient habitat models, we must understand the critical elements that limit habitat. At the northern edge of the geographic range for Chinook salmon, O. tschawytscha, water temperature is a probably a limiting habitat factor. This study investigated the spatial and temporal correspondence between water temperature and Chinook salmon spawning on the Chena River, Alaska. Water temperatures were monitored at 21 stations across 220 river kilometers during the 2006 and 2007 spawning seasons and compared to known thermal requirements for egg development. While an absolute upstream thermal boundary to spawning was not discovered, we describe potential temporal limitations in thermal conditions over the spawning season. Our results show that 98.5% of Chinook salmon selected spawning habitat in which their eggs have a 90% probability of accumulating 450 ATUs before freeze up. This suggests not only temperature conditions limit salmon spawning habitat, but also, as expected, water temperatures temporally limit accessible Chinook salmon spawning habitat at the northern edge of their range. This project documents new spawning habitat for the Anadromous Waters Catalog and broadens the geographical range of Chinook salmon thermal habitat research. It also contributes to the understanding of the processes that define salmon habitat, while providing a baseline for further investigations into water temperature in other thermal regimes.
    • A total environment of change: exploring social-ecological shifts in subsistence fisheries in Noatak and Selawik, Alaska

      Moerlein, Katie J. (2012-05)
      Arctic ecosystems are undergoing rapid changes as a result of global climate change, with significant implications for the livelihoods of arctic peoples. In this thesis, I use ethnographic research methods to detail prominent environmental changes observed and experienced over the past few decades and to document the impact of these changes on subsistence fishing practices in the Inupiaq communities of Noatak and Selawik in northwestern Alaska. Using in-depth key informant interviews, participant observation, and cultural consensus analysis, I explore local knowledge and perceptions of climate change and other pronounced changes facing the communities of Noatak and Selawik. I find consistent agreement about a range of perceived environmental changes affecting subsistence fisheries in this region, including lower river water levels, decreasing abundances of particular fish species, increasingly unpredictable weather conditions, and increasing presence of beaver, which affect local waterways and fisheries. These observations of environmental changes are not perceived as isolated phenomena, but are experienced in the context of accompanying social changes that are continually reshaping rural Alaska communities and subsistence economies. Consequently, in order to properly assess and understand the impacts of climate change on the subsistence practices in arctic communities, we must also consider the total environment of change that is dramatically shaping the relationship between people, communities, and their surrounding environments.