• Phylogeography and population genetics of northern flying squirrels (Glaucomys sabrinus) in Southeast Alaska

      Bidlack, Allison Lynn (2000-08)
      The Prince of Wales flying squirrel (Glaucomys sabrinus griseifrons), a forest associated species, is endemic to several islands in the Alexander Archipelago of Southeast Alaska. Mitochondrial and nuclear markers were examined to assess the genetic uniqueness of this subspecies and its geographic extent and to investigate gene flow among island and mainland populations of flying squirrels. Data from both sets of markers are congruent, and agree with the subspecific designation. The data also indicate that the Prince of Wales subspecies is isolated from other populations in Southeast Alaska, but that there may be gene flow among islands on which it occurs. This island lineage is likely the result of a founder event after the retreat of the Pleistocene ice sheets. The fact that this subspecies is isolated and divergent from mainland populations has potential implications for the design and planning of timber harvests on these islands.
    • Physiological and ecological determinants of nutrient partitioning in caribou and reindeer

      Allaye-Chan, Ann C. (1991)
      The effects of season, migration, and reproduction on the adipose and protein dynamics of barren-ground caribou were determined from field collections of adult females from the Porcupine Herd. Radio-collared females recaptured over time provided data on animals of known reproductive status. Pregnant females averaged a daily loss of 50g body fat and 15g body protein during the last 60 days of gestation. Between June and September, lactating females preferentially deposited body protein but non-lactating females preferentially deposited body fat. In both cohorts, fat deposition increased relative to protein deposition in fall, but maximum fat deposition occurred in summer. Females that conceived averaged 220% more body fat and 17% more body protein than females that did not conceive. Fetal and birth weight positively correlated with maternal protein reserves, but not with maternal fat reserves. Fieldwork on free-ranging caribou were complemented with nutritional experiments on captive animals to determine the effects of energy intake, protein intake, the dietary protein:energy ratio, date, and body condition on nutrient partitioning between fat and protein deposition, and between maternal tissue deposition and milk production. In both lactating and non-lactating females, the proportion of tissue deposited as fat rather than protein increased between spring and fall but decreased with increasing fatness. Lactating and non-lactating females had comparable efficiency coefficients for net energy retention (60% and 65% respectively), but daily maintenance requirement for lactating females (456 KJ/BW$\sp{0.75}$) was twice that for non-lactating individuals (233 KJ/BW$\sp{0.75}$). Energy intake increased protein deposition in lactating females but increased fat deposition in non-lactating females. Production of milk dry matter, fat, and energy were unaffected by maternal energy intake, maternal protein intake, maternal body condition, or calf age. However, production of milk lactose correlated with maternal energy intake, while production of milk protein correlated with the maternal dietary protein:energy ratio. Prediction equations for body weight and composition of barren-ground caribou were developed using bone, muscle, fat, and organ indices. Prediction equations for body weight were validated with an independent data set.
    • Population and habitat analyses for Dall's sheep (Ovis dalli) in Wrangell-St. Elias National Park and Preserve

      Terwilliger, Miranda Lilian Naeser (2005-08)
      We summarized and statistically analyzed historical fixed-wing aerial surveys (1949-2002) and harvest records (1983-2002) of Dall's sheep (Ovis dalli dalIi) from Wrangell-St. Elias National Park and Preserve (WRST). Among survey units there were significant differences in observed densities, hunter-reported harvest, horn lengths of harvested rams, and horn length residuals from the regression of length on age. There was no consistent evidence of net change in WRST-wide sheep density, even though some survey units showed trends in density. Reported harvest in WRST declined linearly during 1973-2003 from 376 to 139 rams per year. We estimated the relationships among population and habitat characteristics with multiple linear regression. We standardized all variables and evaluated all 1, 2, and 3 variable models using Akaike's Information Criterion for small sample sizes (AICc) for model selection. The best model for sheep density showed a positive correlation with median NDVI (relative vegetation greenness) and terrain ruggedness. The same model resulted from examining adult and Iamb cohorts separately. Approximately 50% of horn length was explained by age. The habitat variables estimated did not explain a significant amount of the variance observed in reported harvests or horn length residuals from the regression of length on age.
    • Population Characteristics, Ecology, And Management Of Wolverines In Northwestern Alaska (Gulo-Gulo)

      Magoun, Audrey J. (1985)
      A radiotelemetry study of wolverines was initiated in 1978 as part of a larger research program sponsored by the U.S. Fish and Wildlife Service in northwestern Alaska. The primary goal of this research was to determine aspects of wolverine behavior and ecology that are important to the management of wolverines in northwestern Alaska. Between April 1978 and May 1981, 26 wolverines were captured, 12 males and 14 females; 23 were radiocollared. Nine wolverine kits in five litters were produced by three of the radiocollared females between March 1978 and May 1982. The average rate of reproduction for the study population was 0.6 kits/female/year. Birth of kits occurred in early March. Kits grew rapidly, reaching adult size by November. Resident female wolverines maintained home ranges that were exclusive of other females except their offspring; average summer home range size was 94 km('2). Data were insufficient to determine if adult male home ranges overlapped; overlap did occur between adult and juvenile males. Summer home range size for adult males averaged 626 km('2). Data were insufficient to determine annual home range size. Denning and raising young had a major influence on the movement patterns of adult females. Movements of males were influenced by breeding behavior from late winter through summer. Wolverine social structure appeared to be typical of the intrasexual territoriality of solitary carnivores. Wolverines scentmarked frequently using urine and secretions from the ventral gland and anal sacs. Caribou and ground squirrels were the most important foods. Food was apparently limited during the winter months and influenced wolverine movements and productivity. The presence of caribou and moose may be the most important factor influencing wolverine populations in northwestern Alaska. Wolverines do not appear to be overexploited at this time, but an attempt should be made to obtain more accurate harvest statistics and baseline data to establish wolverine population size and structure in northwestern Alaska.
    • Population dynamics of tundra swans on the lower Alaska Peninsula

      Meixell, Brandt W. (2007-08)
      This study was initiated in response to concerns regarding apparent declines in abundance and breeding pair density of tundra swans on and adjacent to Izembek National Wildlife Refuge (NWR) on the lower Alaska Peninsula. I conducted an analysis of long-term data (1978-1996) to estimate demographic parameters and assess the relationship between survival probabilities and a number of environmental and ecological factors. Rates of productivity (egg, nest, cygnet survival) and annual rates of apparent adult survival were lower and more variable than previously observed for other swan populations and species. A negative relationship between nesting success and brown bear density indicates that depredation by bears is a primary determinant of tundra swan reproductive success. Changes in apparent survival probability were primarily influenced by high and variable rates of permanent emigration. Because of low rates of production and apparent survival, immigration by swans from other breeding areas may be important for sustaining a breeding population of tundra swans on and adjacent to Izembek NWR.
    • Population ecology of Pacific common eiders on the Yukon-Kuskokwim Delta, Alaska

      Wilson, Heather M.; Powell, Abby; Murphy, Edward; Lindberg, Mark; Hollmen, Tuula; Grand, Barry (2007-05)
      Knowledge of ecological factors that influence birth, death, immigration, and emigration provide insight into natural selection and population dynamics. Populations of Pacific common eiders (Somateria mollissima v-nigrum) on the Yukon-Kuskokwim Delta (YKD) in western Alaska declined by 50-90% from 1957 to 1992 and then stabilized at reduced numbers from the early 1990's to the present. This study investigates the primary underlying processes affecting population dynamics of Pacific common eiders, with the goals of understanding factors that may have led to the observed decline and subsequent stabilization, and providing tools from which conservation, management, and recommendations for future research can be drawn. I examined variation in components of survival and reproduction in order to test hypotheses about the influence of specific ecological factors on life history variables and to investigate their relative contributions to local population dynamics. These analyses include data I collected from 2002 to 2004, in addition to historical data collected from 1991 to 2001. Apparent survival of adult females was high and relatively invariant, while components of reproduction were low and variable, both within and among individuals. Timing of nesting and seasonal declines in clutch size and nest survival indicated that females in the early and mid parts of the breeding season produced the highest numbers of offspring; suggesting directional selection favoring early nesting. Probability of a nest containing [1 or less] nonviable egg was positively related to blood selenium concentrations in hens, but no other contaminant-related reductions to life history variables were found. All estimates of population growth ([lamda]) indicated that the YKD population was stable to slightly increasing during the years of the study (range [lamda]: 1.02-1.05 (CI: 0.98-1.11)), and would respond most dramatically to changes in adult female survival. However, historical fluctuations in [lamda] were primarily explained by variation in reproductive parameters, particularly duckling survival. Practical options for increasing adult survival currently may currently be limited. Thus, enhancing productivity, particularly via methods with simultaneous positive effects on adult survival (e.g., predator removal), may offer a more plausible starting point for management aimed at increasing population growth.
    • Population status and patterns of distribution and productivity of kittiwakes on St. George Island, Alaska

      Kildaw, Stewart Dean (1998)
      I studied populations, distributions, and reproductive performance of red-legged and black-legged kittiwakes on St. George Island in the summers of 1993-1995, where populations of both species have experienced generally poor reproductive performance and population declines of ca. 40% over the past 20 years. In 1995, I conducted a whole-island census of kittiwakes on St. George Island and found estimated breeding populations of 193,930 red-legged kittiwakes (81% of their global population), and 62,568 black-legged kittiwakes. In addition, I analyzed census trends on 51 land-based census plots on St. George Island and found that numbers of both species have stabilized in recent years. I experimentally evaluated the hypothesis that nesting red-legged kittiwakes on St. George Island are competitively displaced by larger-bodied black-legged kittiwakes to narrower rock ledges and higher elevations. I determined nest-site preferences of both species by attaching narrow and wide artificial nesting ledges within high-and low-elevation areas of St. George Island and found no evidence of competitive displacement: red-legged kittiwakes preferred narrow ledges, black-legged kittiwakes preferred wide ledges, and both species preferred ledges in areas where conspecifics nested at high density. Multiple regression analyses suggested that kittiwakes breed earlier and more successfully in summers preceded by cold winters and that inter-annual variability in kittiwake breeding success was unrelated to weather conditions during the breeding season itself. These results suggest that winter weather has indirect effects on breeding kittiwakes by influencing prey abundance several months later. Furthermore, strong winds impaired growth rates of kittiwake chicks in exposed nest sites and the growth of black-legged kittiwake chicks relative to red-legged kittiwake chicks. I identified two prominent patterns of within-colony spatial variability in kittiwake productivity and suggest that patchy "bird quality" or localized "information neighborhoods" may be responsible because traditional explanations do not apply. The "information neighborhood" is a new hypothesis which proposes that individuals are influenced by the breeding status of neighbors because their status represents an additional source of information about current breeding conditions that can be used to better tailor parental investment.
    • Postbreeding Ecology Of Shorebirds On The Arctic Coastal Plain Of Alaska

      Taylor, Audrey R.; Powell, Abby N.; Lanctot, R. B.; Huettmann, F.; Kitaysky, A. S.; Williams, T. D. (2011)
      Previous research on the Arctic Coastal Plain (ACP) of Alaska has shown that postbreeding shorebirds congregate at coastal sites prior to fall migration. Relatively little has been done to compare distribution, community characteristics, or behavior broadly across the ACP landscape, but this information is necessary to set the context for interpreting population demographics and setting conservation priorities. I collected data on distribution, species composition, phenology, and habitat use of postbreeding shorebirds in 2005--2007. I found that distribution of shorebirds across the ACP was not uniform: I identified persistent "hotspots" at Peard Bay, Pt. Barrow/Elson Lagoon, Cape Simpson, Smith Bay to Cape Halkett, and at the Sagavanirktok and Kongakut Deltas. Staging phenology varied by species and location, and differed than that reported in previous studies for several species. Three foraging habitat guilds existed with birds favoring gravel beach, mudflat, or salt marsh/pond edge habitats. Using VHF telemetry. I examined how shorebirds moved from tundra breeding sites to and between coastal postbreeding sites. I found that most species exhibited a variable direction of movement compared to their ultimate migration direction; this may be related to each species' overall length of stay on the ACP. I also found species-specific patterns of movements and residence time that were indicative of differing life history strategies. Lastly, I examined the use of physiological tools (triglyceride and corticosterone levels) to assess function and quality of foraging sites for postbreeding shorebirds, taking into account varying molt strategies. I determined that molt strategies affected physiological profiles and physiologic metrics varied through space and time. However, my hypotheses for variation in physiological patterns for shorebirds employing different molt strategies and using sites of varying quality were not completely upheld. I suggest that assessments of site quality for postbreeding shorebirds should consider species-specific life history strategies, and use multiple species and physiological metrics as indicators. Given suspected declines in North American shorebird populations, and accelerated rates of environmental change in northern Alaska, this contextual information regarding postbreeding distribution, population characteristics, behavior, and physiology may help interpret changes in shorebird populations or behavior and establish strategies to protect important habitat.
    • Potential muskox habitat in the National Petroleum Reserve-Alaska: a GIS analysis

      Danks, Fiona Susan (2000-08)
      Muskoxen (Ovibos moschatus), reestablished in northern Alaska in recent decades, have been increasing in number and distribution. However, their selection of habitat within the landscape, historically and presently, remains inadequately documented. This project produced maps of predicted muskox habitat in the National Petroleum Reserve-Alaska (NPR-A), that provide a basis for management of muskoxen and protection of their habitat in relation to proposed oil, gas and mineral exploration. Vegetation analyses showed compositional differences and interactions between vegetation and terrain. Within a geographical information systems (GIS) database, muskox locations, satellite-based vegetation maps and terrain data for the Kuparuk River drainage basin were assimilated, and a maximum likelihood classification developed to produce a habitat selection model incorporating the interactive effects of these characteristics. Using NPR-A GIS data, the model was extrapolated to produce maps showing suitable summer habitat in lower-lying drainages and wetter areas, and suitable winter habitat in drier, more rugged, exposed areas.
    • Prefledging survival and reproductive strategies in black brant

      Flint, Paul Leroy; Sedinger, James S. (1993)
      We develop a general model useful for estimating survival of young waterfowl between hatching and fledging. Our model allows for interchange of individuals among broods and relaxes the assumption that individuals within broods have independent survival probabilities. We consider point estimation of survival rates and corresponding variances of the point estimators. We estimated gosling survival of black brant (Branta bernicla nigricans) during summers of 1987-89 on the Yukon-Kuskokwim Delta, Alaska. Eight-two percent of females radio-marked at hatch fledged at least 1 gosling (brood success). Survival of goslings within broods was estimated by 3 methods: (1) changes in mean brood size through time, (2) observation of goslings associated with marked adults, and (3) age ratios of brant captured in banding drives. Estimates of survival within successful broods averaged 77% and ranged from 57 to 90%. Combining brood success and survival of young within broods yields estimates of overall gosling survival which averaged 64% and ranged from 77% in 1987 to 52% in 1989. We analyzed variation in egg size of black brant in relation to clutch size, laying date, female age, year, and position in the laying sequence. Egg size increased with clutch size and female age, and decreased with laying date, year, and position in the laying sequence. We did not detect a negative phenotypic correlation between clutch size and egg size. However, overlap in total clutch volumes for clutches of different sizes indicated trade offs occurred among individuals with comparable investments in their clutches. We web-tagged black brant goslings at hatch, recorded their egg size, position in the egg-laying sequence, initial brood size, hatch date, and nesting density and examined the effect of these characteristics on their probability of recapture. Larger broods from larger eggs, and with earlier hatch dates were more likely to be recaptured. There was a tendency for young females to be less successful in rearing their broods; however, this may be related to their egg size, initial brood size, and hatch date, rather than age per se.
    • Production of vascular aquatic plants in wetlands of Alaska: A comparative study

      Larsen, Amy Sophia (1997)
      I examined the effects of climate and hydrology on aboveground biomass of macrophytes in wetlands across Alaska by investigating the effects of latitude, July mean air temperature, lake type (open, periodically inundated, and closed), hydrology, and water and sediment chemistry on emergent and submersed vascular plant biomass to determine environmental variables that influenced wetland plant growth. I sampled aboveground biomass of macrophytes in four wetland complexes within Alaska: Kenai and Tetlin National Wildlife Refuges, Minto Flats State Game Refuge, and the Arctic Coastal Plain near Prudhoe Bay, Alaska. In addition to peak aboveground biomass, I also collected water and sediment samples from each lake that were analyzed for water temperature, color, alkalinity, turbidity, pH, orthophosphate, $\rm NO\sb3/NO\sb2$-N, NH$\sb4\sp+$, and total sediment C, N, and P. I found a quadratic relationship between emergent plant biomass and latitude. Minto, the second most northern site, had the greatest plant biomass, Prudhoe Bay, the most northern site had the least, and Kenai and Tetlin had moderate levels of biomass. I found a positive linear relationship between emergent plant biomass and July mean temperature, suggesting that on-site summer condition is important in predicting biomass. Submersed plant biomass was better related to alkalinity, turbidity and sediment P than to latitude, which suggests that climate is not as important in predicting submersed plant biomass as it is in predicting emergent plant biomass. Emergent plant biomass differed spatially and temporally, while submersed plant biomass showed no distinct patterns in variation across the landscape and with changes in hydrologic input. Many water and sediment chemistry variables differed among lake types and between flood regimes. Emergent plant biomass was associated with changes in water level as well as changes in water. Plant species composition differed among lake types and tended to change with flood regime as well. A separate suite of species occupied closed lakes, while open and periodically inundated lakes tended to contain more similar plant species. Both climate and hydrology appear to have a significant impact on emergent and submersed plant biomass and species composition in wetlands of Alaska. These spatial and temporal differences have direct influences on secondary producers living in wetlands of Alaska.
    • A protocol for assessing the impacts of urbanization on coho salmon with application to Chester Creek, Anchorage, Alaska

      Whitman, Matthew S. (2002-08)
      Coho salmon (Oncorhynchus kisutch) abundance has declined in many urban streams. The causes of these declines can be hard to identify because urban impacts on stream ecology are complex and can vary between watersheds. This makes it difficult to develop appropriate and effective strategies for stream rehabilitation or mitigation aimed at increasing coho productivity. To improve this situation I developed a habitat quality assessment protocol for urban coho salmon to help identify significant habitat degradation as a prelude to restoration planning. To evaluate the protocol I used it to assess coho habitat quality in Chester Creek, Anchorage, Alaska, an urban stream that once supported a large population of coho salmon but now only supports a remnant population. I compared habitat characteristics from one non-urban and two urban study reaches to 'healthy' standard guidelines. This application of the protocol showed that the most significant adverse effects of urbanization on coho salmon habitat in urbanized reaches were increased flood intensity, barriers to adult and juvenile migration, reduced physical habitat complexity, siltation of spawning gravels, stressful water quality conditions, and stocking of potential predators and competitors. These results provide useful information for prioritizing rehabilitation and mitigation efforts in Chester Creek.
    • Proximate and ultimate control of reproductive effort in northern shovelers (Anas clypeata) nesting at Minto Flats, Alaska

      Maccluskie, Margaret Christine (1997)
      The purpose of this study was to examine factors that influence reproductive effort of female Northern Shovelers (Anas clypeata) nesting at Minto Flats, AK during summer 1991-1993. I investigated the importance of endogenous nutrient reserves to females during egg production and examined changes in organ weights and intestine lengths through the reproductive cycle. Changes in organ weights and intestine length were similar to those of shovelers nesting in Manitoba. Females used neither somatic lipid reserves, protein reserves, nor mineral reserves to produce eggs. Individual variation in somatic lipid reserves was explained by body size and nest initiation date, while variation in somatic protein reserves was explained by standardized nest initiation date. Somatic mineral variation was explained by differences among years. Neither somatic protein nor mineral reserves were reduced during incubation, but somatic lipid reserves decreased significantly. I conclude that endogenous nutrient availability does not proximately limit clutch size during laying for this population, possibly due to high productivity of interior Alaska wetlands and long days. Little is known about nest attendance behavior of ducks in the subarctic; therefore, I examined shoveler nest attendance patterns at Minto Flats to determine if observed patterns differed from those documented for shovelers nesting in Manitoba, Canada. Shovelers nesting at Minto were less attentive and took more frequent, longer recesses than shovelers in Manitoba. I examined patterns of nest attendance during incubation in relation to clutch volume and female weight loss to determine if females make tradeoffs between energy invested in the clutch and energy invested in incubation. I found no evidence of energetic tradeoffs by Shovelers nesting at Minto Flats. To determine if the trait of synchronous hatching could limit clutch size for a species of the genus Anas I measured development time and metabolic rates of Mallard (Anas platyrhynchos) eggs incubated in a constant environment. Females varied in length of time their eggs required to reach the star-pipped stage of hatch. Metabolic rate of eggs varied positively with position in the laying sequence and varied among females. These results indicate that metabolic rate may act as a synchronization mechanism for hatch.
    • Range, movements, population, and food habits of the Steese-Fortymile caribou herd

      Skoog, Ronald O. (1956-05)
      The Steese-Fortymile caribou (Rangifer arcticus stonei Allen) form one of the most economically important herds in Alaska. This study of the herd took place from September, 1952, to December, 1955, under the auspices of the Alaska Cooperative Wildlife Research Unit at the University of Alaska and of the Federal Aid in Wildlife Restoration branch of the United States Fish and Wildlife Service, Project W3R. The Steese-Fortymile range occupies about 35,000 square miles of east-central Alaska and the Yukon Territory, lying mainly between the Tanana and Yukon Rivers. The terrain is mountainous, but not rugged; roads and towns are scarce, and a maximum of 60,000 people live on the fringes. Seven major plant communities comprise the range vegetation, three of them covering 60 to 70 per cent of the area and furnishing the bulk of the food for caribou. The carrying capacity is computed to be 70,000 to 90,000 caribou. The erratic and continual movements of caribou characterize this game species. Their movements vary from day to day and season to season. Most of the traveling takes place during the early morning and late afternoon; major seasonal movements take place in the spring and fall. Past and present data provide a general picture of the movement pattern of this herd throughout the year. The Steese-Fortymile herd dwindled from a peak of about 500,000 animals in the late 1920's to a low of 10,000 to 20,000 in the early 1940's. The decline is attributed to a population shift. The present population contains at least 50,000 animals and is increasing steadily. Reproduction was high during the years 1950 to 1955. The rut takes place during the first two weeks of October; most of the calves are born during the latter half of May, following a gestation period of about 33 weeks. Valuable information on caribou behavior during the calving period is presented. Counts taken in May show that at least 50 per cent of the calves survive the first year. Wolf and man are the most important mortality factors affecting this herd. The total annual mortality, excluding calves, is estimated at eight per cent. Sex and age data from composition counts and hunter-checking-station operations indicate that this herd is young and that the sex ratio approaches 100:100. The annual increment for the herd is computed to be 10 to 15 per cent. Caribou are cursory feeders and eat a wide variety of plants. The main periods for resting and feeding occur during the middle portions of the day and night. The caribou’s diet hinges upon the available food supply, and thus varies with the seasons. In winter, the diet consists mostly of lichens, grasses, and sedges, with browse plants of some importance; data from 23 stomach-samples are presented. In spring, the new shoots of willow, dwarf birch, grass, and sedge are most important; information is based only on field observations. In summer, a wide variety of plants are eaten; willow and dwarf-birch foliage are of greatest importance, followed closely by grasses and sedges; data from 27 stomach-samples are presented. In fall, the diet shifts from a predominance of woody plants and fungi in late August to one of lichens, grasses, and sedges in late September; data from 70 stomach-samples are presented. The problems of data-gathering are discussed, as related to management practices. The contributions made by this report are outlined, and the important information still needed for proper caribou management is listed.
    • A rapid assessment method to estimate the distribution of juvenile chinook salmon (Oncorhynchus tshawytscha) in an Interior Alaska river basin

      Matter, Allison N.; Falke, Jeffrey; Sutton, Trent; Savereide, James; Lopez, J. Andres (2016-08)
      Identification and protection of water bodies used by anadromous species in Alaska are critical in light of increasing threats to fish populations, yet challenging given budgetary and logistical limitations. Non-invasive, rapid assessment sampling techniques may reduce costs and effort while increasing species detection efficiencies. I used an intrinsic potential (IP) habitat model to identify high quality Chinook Salmon Oncorhynchus tshawytscha rearing habitats and select sites to sample throughout the Chena River basin for juvenile occupancy using environmental DNA (eDNA) and distribution within tributaries using snorkel surveys. Water samples were collected from 75 tributary sites in 2014 and 2015. The presence of Chinook Salmon DNA in water samples was assessed using a quantitative polymerase chain reaction (qPCR) assay targeting that species. Snorkel surveys were conducted and physical habitat was measured for a subset of tributaries examined with the eDNA approach. Juvenile salmon were counted within 50 m reaches starting at the tributary confluence and continuing upstream until no juvenile salmon were observed. The IP model predicted over 900 stream km in the basin to support high quality (IP ≥ 0.75) rearing habitat. Occupancy estimation based on eDNA samples indicated that 80.2% (± 4.3 SE) of previously unsampled sites classified as high IP and 56.4% of previously unsampled sites classified as low IP were occupied. The probability of detection of Chinook Salmon DNA from three replicate water samples was high (0.76 ± 1.9 SE) but varied with drainage area. A power analysis indicated power to detect proportional changes in occupancy based on parameter values estimated from eDNA occupancy models. Results of snorkel surveys showed that the upper extent of juvenile Chinook Salmon within tributaries was from 200 to 1,350 m upstream of tributary confluences. Occurrence estimates based on eDNA and snorkel surveys generally agreed, but care should be taken to ensure that little temporal gap exists between samples as juvenile salmon use of tributary habitats is likely often intermittent. Overall, the combination of IP habitat modeling, occupancy estimation based on eDNA, and snorkel surveys provided a useful, rapid-assessment method to predict and subsequently quantify the distribution of juvenile salmon in previously unsampled tributary habitats. These methods will provide tools for managers to rapidly and efficiently map critical rearing habitats and prioritize sampling efforts to expand the known distribution of juvenile salmon in interior Alaska streams.
    • Recent changes in plant and avian communities at Creamer's Refuge, Alaska using field and remote sensing observations

      Tauzer, Lila Maria; Powell, Abby; Bret-Harte, Syndonia; Sharbaugh, Susan; Prakash, Anupma (2013-05)
      Plant communities in the north are being profoundly altered by climate warming, but our understanding of the extent and outcomes of this ecosystem shift is limited. Although it was assumed local vegetation changes will affect avian communities, few data exist to investigate this relationship. In an interior Alaska boreal forest ecosystem, this study capitalized on available resources to assess simultaneous change in plant and avian communities over 35 years. Biological changes were quantified in summer avian community data (species composition, diversity, and richness) and in vegetation using archived field data, and supplemented this data with remote sensing observations for a similar time period to assess the validity of this method for documenting environmental change. Field and remote sensing data both documented successional changes resulting in denser, more coniferous-dominated habitats. Birds responded accordingly, which indicates a rapid avian response to habitat change and that they are good indicators of environmental change. Information gained provides more accurate evaluations of habitat dynamics throughout the interior boreal forest and highlights the importance of considering successional change in all long-term climate studies. It allows for better predictions of future habitat change and acts as a strong baseline for future environmental monitoring.
    • Red squirrel (Tamiasciurus hudsonicus) ecology during spruce cone failure in Alaska

      Smith, Michael C. T. (1967-05)
      Observations were made on a red squirrel (Tamiasciurus hudsonicus) population in a mature white spruce (Picea glauca) forest near Fairbanks, Alaska, during two years of spruce cone crop failure (July, 1964, to April, 1966). An adequate supply of old spruce cones, cached in previous years, was available during the first winter. A 67% drop in numbers of the squirrel population followed the second crop failure with the remaining squirrels utilizing spruce buds as their primary food during the winter. Stomach analyses revealed that when present, spruce seed is the major constituent in the diet. In its absence, heavy utilization of mushrooms in summer and spruce buds in winter occurs. Feeding trials conducted with captive red squirrels in March, 1965, and April, 1966, showed that about 194 old cones per day were necessary to sustain a squirrel, approximately 35% more than for cones from the current year's crop. Three squirrels survived for eight days on a diet of only white spruce buds. Analysis of old spruce cones showed that 31% of the seed was potentially viable (filled), but that only 1.4% of the seed germinated. Calorimetric determinations of old seed (minus coat), spruce buds, and mushrooms yielded values of 5,976, 4,986, and 4,552 cal/g respectively. Excavation of middens revealed up to 8,518 old, cached cones per midden, despite a crop failure. In years of normal cone production, squirrels may cut and cache 12,000 to 16,000 cones; the excess accrues each year and eventually a sufficient supply exists to maintain the squirrels through a winter following a cone crop failure.
    • Regional climate, federal land management, and the social-ecological resilience of southeastern Alaska

      Beier, Colin Mitchell (2007-08)
      Complex systems of humans and nature often experience rapid and unpredictable change that results in undesirable outcomes for both ecosystems and society. In circumpolar regions, where multiple converging drivers of change are reshaping both human and natural communities, there is uncertainty about future dynamics and the capacity to sustain the important interactions of social-ecological systems in the face of rapid change. This research addresses this uncertainty in the region of Southeast Alaska, where lessons learned from other circumpolar regions may not be applicable because of unique social and ecological conditions. Southeast Alaska contains the most productive and diverse ecosystems at high latitudes and a human population almost entirely isolated and embedded in National Forest lands; these qualities underscore the importance of the region's climate and federal management systems, respectively. This research presents a series of case studies of the drivers, dynamics, and outcomes of change in regional climate and federal management, and theoretically grounds these studies to understand the regional resilience to change. Climate change in Southeast Alaska is investigated with respect to impacts on temperate rainforest ecosystems. Findings suggest that warming is linked to emergence of declining cedar forests in the last century. Dynamics of federal management are investigated in several studies, concerning the origins and outcomes of national conservation policy, the boom-bust history of the regional timber economy, and the factors contributing to the current 'deadlock' in Tongass National Forest management. Synthesis of case study findings suggests both emergent phenomena (yellow-cedar decline) and cyclic dynamics (timber boom-bust) resulting from the convergence of ecological and social drivers of change. Adaptive responses to emergent opportunities appear constrained by inertia in management philosophies. Resilience to timber industry collapse has been variable at local scales, but overall the regional economy has experienced transition while retaining many of its key social-ecological interactions (e.g., subsistence and commercial uses of fish and wildlife). An integrated assessment of regional datasets suggests a high integrity of these interactions, but also identifies critical areas of emergent vulnerability. Overall findings are synthesized to provide policy and management recommendations for supporting regional resilience to future change.
    • Reindeer Range Appraisal In Alaska

      Pegau, Robert Elwyn (1968)