• Daily heterogeneity in habitat selection by the Porcupine Caribou Herd during calving

      Jones, Rachel Rands (2005-08)
      Caribou exhibit scale-dependent habitat selection, but variance in daily habitat selection by the Porcupine Caribou Herd (PCH) has not been examined. Investigating temporal variance in habitat selection may clarify the time period when managers may accurately estimate calving-related habitat selection. Annually, 1992-1994, approximately 70 calves were radio-collared within 2 days of birth and relocated daily until departing the calving grounds. We used daily 99% fixed kernel utilization distributions (UD's) to estimate caribou distributions, then estimated daily habitat selection using logistic regression. Habitat variables included relative vegetation greenness, greening rate, landcover class, and elevation. Spatial scales of investigation included concentrated vs. peripheral use within daily UD's, daily use within the merged extent of all daily UD's, and daily use within the historical extent of calving, 1983-2001. We used linear regression of logistic regression parameter estimates on sequential sampling days to estimate temporal habitat selection trends during the 3 weeks following capture. Overall, caribou exhibited habitat selection at multiple scales, without temporal trends, suggesting that the 21-day period following capture constituted a single domain and that managers may accurately estimate calving-related habitat selection at any point during this period.
    • Demographic components of philopatry and nest-site fidelity of Pacific black brant

      Lindberg, Mark Steven; Sedinger, James S. (1996)
      I investigated demographic components of nest-site fidelity and philopatry of Pacific black brant (Branta bernicla nigricans). My analyses included data I collected during summer 1990-1993, and also incorporated data obtained between 1986-1989. My studies of nest-site fidelity were limited to the Tutakoke River colony, Yukon-Kuskokwim River Delta, Alaska. Studies of philopatry and dispersal among colonies included observations at 7 breeding colonies of brant marked with tarsal tags (n = 20,147). I observed strong evidence that philopatry of brant was female biased. Probability of breeding philopatry, which was estimated with multi-state modeling techniques, was high (>0.9) and dispersal of adults among breeding colonies was rare. I developed an ad hoc estimator for natal philopatry that was unbiased by a confounding of homing, survival, and detection probabilities. Probability of natal philopatry for females was both age and density dependent. The density-dependent decline in natal philopatry may result from increased rate of permanent nonbreeding or increased probability of dispersal. Observed probability of natal philopatry for males was approximately equivalent to the relative size of their natal colony, suggesting that males pair at random with females from other colonies. Gene flow among populations of brant is largely male mediated, and I predict populations of brant will exhibit distinct mitochondrial DNAs if populations have been reproductively isolated for an adequate period of time. Probability of fidelity to previous nest sites for adults was high (>0.7). Probability of nest-site fidelity was affected by previous nesting success, age, and availability of nest sites. Phenology of nesting, nest-site selection, and clutch size of brant was affected by spring snowmelt. Dispersal of brant from traditional nest sites in years with late springs may represent a tradeoff between site fidelity and timing of nest initiation. Movement of young females from natal nest sites was a mechanism for colony expansion. I observed little evidence that site fidelity was advantageous, and concluded that quality of individual bird, environmental conditions, and demographic status may be more important determinants of breeding performance.
    • Description and identification of larval fishes in Alaskan freshwaters

      Sturm, Elizabeth Anne (1988-05)
      Identification of larval fish is important for assessing fish populations and human impact on fish ecosystems but is difficult due to subtle differences between larvae of different species. A key to larval fishes is valuable for successful population studies. This thesis is a preliminary study towards the development of a key to the larval stages of Alaskan freshwater fishes. Early life history information on 23 of approximately 40 Alaskan freshwater species was obtained from the literature. Six of these species (sheefish, Stenodus leucichthys; Arctic grayling, Thymallus arcticus; Arctic char, Salvelinus alpinus; Dolly Varden, S. malma; longnose sucker, Catostomus catostomus; and slimy sculpin, Cottus coqnatus) were laboratory-reared or collected near Fairbanks for additional information. Technical illustrations and morphometric data were prepared for each of the six species. This study indicates that follow-up research on several whitefishes will be critical for developing a comprehensive larval fish key to Alaskan freshwater species.
    • Duckling survival and incubation behaviors in common goldeneyes in Interior Alaska

      Schmidt, Joshua Harold (2004-08)
      The lack of research on the common goldeneye (Bucephala clangula) in Interior Alaska prompted this study. My objectives were to estimate duckling survival relative to several explanatory variables and to characterize incubation behaviors in a subset of females nesting in the Chena River State Recreation Area. My estimates of duckling survival were higher than previously reported for this species: 0.65 (95% CI 0.49 to 0.82) and 0.68 (95% CI 0.58 to 0.79) for 2002 and 2003 respectively. Seasonally, duckling survival increased linearly throughout 2002, remained nearly constant in 2003, and was negatively related to daily precipitation in both years. Nest attendance patterns and incubation behaviors were not related to weather, female experience, clutch size, or day of incubation. Average number of recesses per day (2.9 ± 0.05), length of recesses (100.7 ± 1.5 min), and incubation constancy (79.8 ± 0.3%) were similar to values previously reported for this species (mean ± SE). I observed nocturnal recesses in this population. Although not previously reported for this species, these recesses may occur due to extended daylight hours during the incubation period.
    • Ecological and physiological aspects of caribou activity and responses to aircraft overflights

      Maier, Julie Ann Kitchens (1996)
      I investigated the use of remote-sensing of caribou (Rangifer tarandus) activity to assess disturbance of low-altitude overflights by jet aircraft. Resource management agencies are concerned about the potential effects of these overflights on important species of ungulates. I hypothesized that low-altitude overflights would affect activity and movements of caribou, and thereby constitute a disturbance with negative consequences on energetics. I used caribou of the Delta Herd (DCH) and captive animals at the Large Animal Research Station (LARS) to address the hypotheses: caribou (1) exhibit equal activity day and night; (2) do not time activity to light; and (3) activity patterns do not change seasonally in response to daylength. Caribou were nychthemeral and exhibited uniform activity with no apparent timing to light. DCH caribou responded to seasonal changes in the environment by modifying activity (increased activity in response to insect harassment), whereas LARS caribou altered activity in response to fluctuating physiological variables (increased activity during rut). Changes in daylength did not affect activity. Data on activity from LARS and DCH caribou were compared with extant data on caribou of the Denali and Porcupine herds. Poor quality forage in winter was inferred from long resting bouts, and low availability of forage was inferred from long active bouts of post-calving caribou of the DCH. In midsummer, caribou of the DCH exhibited significantly longer active and shorter resting bouts than did LARS caribou, consistent with a moderate level of insect harassment. Responses of caribou to overflights were mild in late winter and, thus, overflights did not constitute a disturbance. Post-calving caribou responded to overflights by increasing daily activity, linear movements, incremental energy cost, and average daily metabolic rate. Energetic responses and movements were significantly related to the loudest overflight of the day. In the insect season, activity levels increased significantly in response to overflights but with no corresponding increase in linear movements or energetics. My recommendations are to prohibit aircraft overflights of caribou during calving and post-calving periods and during key feeding times in insect harassment seasons. Research indicates the possibility of more severe effects in nutritionally stressed animals.
    • Ecological effects of invasive European bird cherry (Prunus padus) on salmonid food webs in Anchorage, Alaska streams

      Roon, David A.; Wipfli, Mark; Prakash, Anupma; Wurtz, Tricia (2011-08)
      Invasive species are a concern worldwide as they can displace native species, reduce biodiversity, and disrupt ecological processes. European bird cherry (Prunus padus) (EBC) is an invasive ornamental tree that is rapidly spreading and possibly displacing native trees along streams in parts of urban Alaska. The objectives of this study were to: 1) map the current distribution of EBC along two Anchorage streams, Campbell and Chester creeks, and 2) determine the effects of EBC on selected ecological processes linked to stream salmon food webs. Data from the 2009 and 2010 field seasons showed: EBC was widely distributed along Campbell and Chester creeks; EBC leaf litter in streams broke down rapidly and supported similar shredder communities to native tree species; and EBC foliage supported significantly less terrestrial invertebrate biomass relative to native deciduous tree species, and contributed significantly less terrestrial invertebrate biomass to streams compared to mixed native vegetation, but riparian EBC did not appear to affect the amount of terrestrial invertebrate prey ingested by juvenile coho salmon (Oncorhynchus kisutch). Although ecological processes did not seem to be dramatically affected by EBC presence, lowered prey abundance as measured in this study may have long-term consequences for stream-rearing fishes as EBC continues to spread over time.
    • Ecological factors influencing fish distribution in a large subarctic lake system

      Plumb, Miranda Paige (2006-05)
      The coastal climate and frequent wind storms in southwest Alaska create an atypical thermal environment (non-stratified in summer) in the remote Ugashik lakes. This study documents the distribution of lake trout 'Salvelinus namaycush, ' arctic char 'S. alpinus', Dolly Varden 'S. malma, ' arctic grayling 'Thymallus arcticus, ' round whitefish 'Prosopium cylindraceum, ' and pygmy whitefish 'P. coulterii' relative to depth, substrate particle size, food habits, length, and age in the absence of strong thermal structure. Sample sites were randomly chosen within sampling strata and gill nets were set at each site. Lake trout and round whitefish were most abundant and had the oldest individuals in the catch. In more typical thermally stratified lake systems lake trout and Arctic char usually move to colder, deeper water in summer. In the Ugashik lakes, however, both species were abundant in shallow water all summer. Prior to this study pygmy whitefish were undocumented in this system. The fish examined in the Ugashik lakes were opportunistic feeders, consuming organisms such as isopods and amphipods. Fish in the Ugashik lakes were found in locations different from what one would expect from predominant literature. Fisheries managers may need to take this into account in their fisheries management.
    • Ecology of Prince of Wales spruce grouse

      Nelson, Aleya R. (2010-12)
      Recently, spruce grouse on Prince of Wales Island (POW) in southeast Alaska have been proposed as a separate subspecies. Furthermore, life-history of spruce grouse on POW, which is temperate coastal rainforest, varies sufficiently from birds in mainland areas, mostly boreal forest, to warrant specific management. Therefore, I examined the ecology of spruce grouse on POW to determine how timber harvest influences their survival and habitat selection and ultimately to provide recommendations for their conservation. During 2007-2009, we found that the greatest variation in survival probability was attributed to breeding status. The annual survival of non-breeding birds was 0.72±0.082 (S±) while for breeding birds it was 0.08±0.099. Logging did not adequately predict survival, with no differences among habitats. Conversely, I found differences in selection among habitats. At the watershed scale, spruce grouse preferred unharvested forest. At both watershed and homerange scales, spruce grouse avoided edges and preferred roads. Road-related mortality was the largest known source of death. POW spruce grouse and mainland subspecies exhibit sufficiently different survival rates and habitat preference to warrant specific management. We recommend limited road closures during periods when POW spruce grouse are most vulnerable due to the high rates of mortality associated with this preferred habitat.
    • Ecology of slimy sculpin (Cottus cognatus) in the Chena River, Alaska

      Sonnichsen, Sandra K. (1981-12)
      The purpose of this study was to gather information on the ecology of slimy sculpin (Cottus cognatus) in the upper Chena River. Three major topics were examined: age and growth, food habits, and habitat preferences. Age of fish was analyzed by length frequency and otoliths. Chena River sculpin were slow growing, reaching a maximum length of 86 mm in 7 years. Stomach contents were examined to determine contribution of different prey to the diet. Chironomids and large mayflies were most important in the diet; electivity indices indicated positive selection for them. Habitat preferences were examined by capturing fish, and measuring habitat variables at the point of capture. These data were analyzed using multiple regressions on principal components. No significant correlation was found between number of sculpin caught and habitat variables of depth, velocity, and substrate type.
    • The ecology of the Arctic char and the dolly varden in the Becharof Lake drainage, Alaska

      Scanlon, Brendan P. (2000-12)
      Becharof Lake is home to both Arctic char (Salvelinus alpinus) and the closely related Dolly Varden (Salvelinus malma), two species known not only to be similar in appearance but also to exhibit similar life histories. The body morphometry, otolith microchemistry, and stomach contents of both species were studied in fish collected from May to September 1998. Morphometric and meristic analysis revealed clear separation in body structure between the two species, as well as potential sub-populations within each species. Otolith microchemistry revealed incidences of anadromy and non-anadromy in both species. Stomach content analysis revealed a broad feeding niche but smaller ranges in food types in individual Arctic char with little seasonal preference, whereas Dolly Varden showed seasonality in food choices. Data suggest that both species can move in and out of the lake system, and that little competition for food or habitat occurs between the two species in the summer months.
    • The ecology of wolverines in southcentral Alaska

      Gardner, Craig L. (1985-05)
      A study of wolverine (Gulo gulo) ecology was conducted within the upper Susitna Basin in south central Alaska between May 1980 and April 1982. The study was initiated in an attempt to identify potential impacts of hydroelectric development on the wolverine populations. Twelve wolverines (10 males) were fitted with radio transmitters and relocated 153 times. The mean winter and summer home ranges for adult males were 353 km2 and 385 km2, respectively. Adult male home ranges were primarily mutually exclusive, having an average overlap of 4.2% between neighbors. On an annual basis, wolverines appeared to select spruce cover types; this selection was strongest during the winter. The most important foods to wolverines were carrion of ungulates (winter) and ground squirrels (summer). The wolverine population in the Susitna Basin during the study period was not heavily exploited by man and was secure.
    • Effects of antimony mining on stream invertebrates and primary producers in Denali National Park, Alaska

      Wedemeyer, Kathleen (1987-12)
      Heavy metals, primarily antimony, arsenic and manganese from antimony mines in Denali National Park, Alaska impacted all levels of the stream ecosystem. Decreased algal, moss and macroinvertebrate abundance (but not changes in macroinvertebrate trophic organization) were all clearly associated with mining activity in Slate and Eldorado creeks. Crustacea, Chironomidae (Diptera), Hydracarina (Arachnida), Nemouridae (Plecoptera), and Zapada (Nemouridae) decreased in relative abundance with metal pollution while Capniidae (Plecoptera), Nemoura (Nemouridae), and Podmosta (Nemouridae) increased in relative abundance at mine sites. The data from Stampede Creek demonstrated that mineralized but unmined stream reaches may be impacted by heavy metals. Unexpectedly higher selenium levels upstream of the mine may account for the general lack of substantial differences in macroinvertebrates and periphyton upstream and downstream of the mine. However, macroinvertebrate and periphyton abundances were lower at both sites on Stampede Creek than at the unmined control stream, Jumbo Creek.
    • The effects of barotrauma and deepwater-release mechanisms on the reproductive viability of yelloweye rockfish in Prince William Sound, Alaska

      Blain, Brittany; Sutton, Trent; Seitz, Andrew; Erickson, Jack (2014-12)
      Previous research has shown that releasing sport-caught Yelloweye Rockfish Sebastes ruberrimus with a deepwater-release mechanism (DRM) can alleviate anatomical damage due to barotrauma. However, it is unknown if a Yelloweye Rockfish remains a viable member of the population and reproduces in subsequent years following a barotrauma event and recompression with a DRM. The objectives of my study were to: 1) determine if Yelloweye Rockfish were able to reproduce one to two years following known forced decompression and recompression event(s); and 2) evaluate if barotrauma and recompression affected the quality of developing embryos. In 2010, Yelloweye Rockfish were sampled from an isolated reef in Prince William Sound, Alaska. Fifteen females tagged in 2008 and 2009 were recaptured in 2010, and reproductive status was identified by visual observation of the gonads and hematological sampling (i.e., vitellogenin and calcium²⁺ plasma concentrations). Oil globule volume, percent lipid, and caloric content were also measured for the embryos from seven of these females and these values were compared to embryos from 13 females with no previously documented barotrauma and recompression events. These results showed that all 15 Yelloweye Rockfish recaptured in 2010 were gravid (with eggs) or spent (having released eggs). In addition, there were no differences in median oil globule volume, caloric content, and percent lipid between individual embryos from new captures and recaptures. Results indicated that there is no evidence that reproduction and embryo quality of Yelloweye Rockfish is adversely affected one to two years following forced decompression and recompression with a DRM at the depths sampled in this study. This research provides information on the utility of DRMS as a tool for rockfish conservation and supports the importance of utilizing these devices by sport anglers.
    • Effects of bear viewers and photographers on brown bears (Ursus arctos) at Hallo Bay, Katmai National Park and Preserve

      French, Howard Blair (2007-05)
      We investigated the effects of bear viewing and photography on brown bears (Ursus arctos) that used open habitats at Hallo Bay, Katmai National Park and Preserve (KNPP), Alaska. We also investigated how bear use of the area varied with season, human presence, and time of day. We found that the mean number of bears present varied significantly with season, time of day, and human presence. There were significantly more bears present before the salmon season than during the salmon season; bear numbers increased significantly during the day, and there were significantly more bears when humans were present. Humans at varying distances least affected activity budgets of sows with spring cubs, but foraging efficiency (bites per minute) of sows with spring cubs was significantly lower with humans <50 m away than with humans absent. Fishing success (chases per catch) of large males and single bears was lower when humans were present, but fishing success of sows with spring and older cubs was higher when humans were present. We conclude that humans are affecting brown bears that use Hallo Bay and therefore the Katmai NPP Bear Management Plan is being violated as well as the act establishing the National Park Service. We recommend that managers at KNPP restrict visitor use at Hallo Bay and enforce existing policy.
    • Effects of elevated sediment levels from placer mining on survival and behavior of immature arctic grayling

      Scannell, Patrick O. (1988-12)
      The effect of placer mining effluents on Arctic grayling (Thymallus arcticus) fingerling and egg survival was tested in mined and unmined streams in interior Alaska. Also the influence of turbidity on Arctic grayling reactive distance and avoidance behavior was tested in a laboratory choice chamber. Arctic grayling fingerlings suffered less than 1% mortality during a 96-hr toxicity test in both clear (mean NTU = 1.4) and mined (mean NTU = 445) streams. Arctic grayling eggs did not show significantly (p > 0.1) higher mortality in mined streams than in unmined streams. In a laboratory choice chamber test, Arctic grayling avoided water with a turbidity above 20 NTU (nephelometric turbidity units). Arctic grayling reactive distance diminished proportional to the natural logarithm of turbidity.
    • Effects of fish wheels on fall chum salmon (Oncorhynchus keta): non-esterified fatty acids and plasma indices of stress

      Cleary, Peter Mallon (2003-05)
      The effect of tagging and capture on plasma concentrations of cortisol, glucose, lactate, chloride, and non-esterified fatty acids (NEFA) in chum salmon was investigated. Adult chum salmon were captured in August-September 2000 and 2001 with a fish wheel on the lower Kantishna River. Tagged and untagged fish were subsequently captured on the lower Toklat River and sampled for blood. Tagged fish (males and females) at the Toklat recovery fish wheels had lower (P <0.04) plasma cortisol concentrations than untagged fish. Glucose concentrations were lower (P = 0.03) in tagged than untagged males but did not differ between tagged and untagged females. Lactate and chloride concentrations did not differ between tagged and untagged fish. Tagged chum salmon captured at the Toklat River recovery wheels had lower concentrations of NEFA (P = 0.02). Taken together, these results suggest there is a metabolic cost from capture and tagging using fish wheels.