• Black bear denning ecology and habitat selection in interior Alaska

      Smith, Martin E.; Follmann, Erich; Dean, Fred; Hechtel, John; Bowyer, Terry (1994-12)
      To identify conflicts between existing black bear (Ursus americanus) management and human activity on Tanana River Flats, Alaska, we monitored 27 radio-collared black bears from 1988-1991. We compared denning chronology, den characteristics, den-site selection, and habitat selection across sex, age, and female reproductive classes. Mean den entry was 1 October and emergence was 21 April, with females denned earlier and emerging later than males. Marshland and heath meadow habitats were avoided, and willow-alder was selected for den-sites. Eighty-three percent of dens were excavated, 100% contained nests, 18% were previously used, and 29% had flooded. Black bears selected black spruce-tamarack and birch-aspen significantly more, and marshland and heath meadow significantly less than available. Marshland and birch-aspen were used significantly more in spring than autumn. Marshland was used less than available by all bears in all seasons. Special habitat or den-site requirements are not critical for management of Tanana River Flats black bears.
    • Characterization of muskox habitat in northeastern Alaska

      O'Brien, Constance Marsha (1988-12)
      In northeastern Alaska, muskoxen have been most often found in riparian habitats and proximate uplands. Vegetation was studied in nine adjacent river drainages; six of the drainages are regularly used by muskoxen. Twenty-two vegetation/land cover types were described using aerial photographs, point-intercept sampling, and ocular cover estimates. The proportion of each cover type was estimated for each drainage and compared among drainages by MANOVA. There was no significant difference among non-muskox drainages in the average proportion of cover types. A marginally significant difference was found among muskox drainages. There were no significant differences in the proportions of each vegetation type in non-muskox drainages versus muskox drainages. Five vegetation types associated with high forage quality and availability and low snow accumulation were often used by muskoxen. Four of these five vegetation types typically had <7% cover in the nine drainages and are critical habitat components in northeastern Alaska.
    • 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.
    • Marine associated bird and mammal habitat use at the Five Finger Lighthouse Island

      Beraha, Lori (2018-07)
      In summer 2017 I studied the abundance and distribution of marine associated birds and mammals from four observational points on the southernmost of the Five Finger Islands (FFI). My objectives were (1) to identify the areas of highest habitat use by species of conservation concern, and (2) to use this information to make recommendations for an ecosystem-based management plan at the Five Finger Lighthouse Island (FFLI). I found higher relative abundance and higher biodiversity of both birds and marine mammals on the South and West facing sectors compared to the North and East facing sectors. I attribute this to the greater habitat complexity that comprises a near-shore reef, a mixed kelp forest, and a channel between the reef and the side of the island with the highest cliff, areas used extensively for foraging, nesting, traveling, socializing, and resting by many of the documented species. I therefore recommend avoiding development and minimizing anthropogenic disturbance on the southern and western portions of the island including the adjacent reef and channel between the reef and island. As both the FFI ecosystem and the Five Finger Lighthouse (FFL) management continue to evolve in response to changing environmental conditions and human needs, this study provides a useful baseline for future comparison. Continued study and monitoring is also recommended at this site to inform future adaptive management, document changes over time, and engage community stakeholders in science and conservation.
    • Moose (Alces alces) browse enhancement and sustainable forestry as a rural development tool in the sub-Arctic boreal forest region of Alaska

      Cain, Bruce David (2014-05)
      This project studies indigenous and western moose browse management issues in the sub-arctic boreal forest and how this topic relates to rural development. Chapter one explains the methodology of the project. Chapter two describes how moose browse and biomass management support rural development and investigates productivity potential of combining moose browse management with sustainable forestry and biomass production. Chapter three investigates landscape and habitat management principles from a customary and traditional practice versus a scientific approach. It looks at management models in the following territories: Alaska, Canada, Continental US, Mongolia/Russia and Scandinavia. Chapter four investigates indigenous wildlife management systems and other indigenous wildlife policy issues. Chapter five is a selected annotated bibliography. The project has a focus on the Ahtna region of central Alaska and recognizes the implications of these issues for this region.
    • Nutritional ecology of moose in an urban landscape

      Welch, Joseph H.; Barboza, Perry; Hundertmark, Kris; Spalinger, Don; Farley, Sean (2012-08)
      Joint Base Elmendorf-Richardson (JBER), Alaska supports a large population of moose that lives in and around the urban and industrial development of Anchorage. This study evaluates the body condition of adult female moose on JBER and calculates the relative nutritional value of habitat for planning development and for mitigating the effects of development on this population. Body condition of moose on JBER was similar to that of other populations of moose in Alaska. Our nutritional model predicted that shrublands could support 11-81 times more moose than any other habitat on JBER. Activity patterns of JBER moose were similar to those published for non-urban moose, indicating habituation to human activity. Activity levels increased as moose moved through higher quality habitats. Sustained production of this heavily utilized population requires maintaining shrublands in undeveloped portions of the base where moose-vehicle collisions can be minimized.
    • Otters, sea stars, and glacial melt: top-down and bottom-up factors that influence kelp communities

      Traiger, Sarah B.; Konar, Brenda; Hardy, Sarah; Okkonen, Stephen; Edwards, Matthew; Litaker, Wayne (2017-08)
      Kelp beds are important features of the Alaska coastline and provide habitat, protect coastlines, and support commercial and subsistence harvests. Kelp beds are affected by top-down and bottom-up factors, which are changing due to human and climate-related impacts. The influences of these top-down and bottom-up factors on kelp beds are investigated in three chapters. My first chapter investigated the influence of glacial discharge on recruitment and early community development in subtidal kelp communities by monitoring benthic sessile algae and invertebrates on cleared rocks across a glacial gradient along with various physical and biological parameters in the summers of 2013-2014. It has been predicted that Alaska's glaciers will lose 30-60% of their volume by 2100. The melt from glaciers increases sedimentation and lowers salinity, impacting important habitat-providing kelp. I found that sites upstream from glacial discharge had higher kelp recruitment than downstream sites, and that up to 72% of the variation in community development was related to mobile invertebrates and kelp in the surrounding community. Glacially-influenced environmental factors did not explain any variation that was not already explained by biological factors. My second chapter explored whether patterns in the recruitment of the dominant canopy kelp, Nereocystis luetkeana and the subcanopy kelp, Saccharina latissima were a result of dispersal limitation or failure to grow to macroscopic size. My goals were to determine 1) whether glacial melt conditions affect adult fecundity (spore production) of either species, 2) how sedimentation affects early gametophyte growth and survival in each species, and 3) whether competitive interaction between species at the gametophyte stage is altered by sediments. I found that glacial melt conditions did not affect the fecundity of either species, but sedimentation affected survival and competition. Saccharina latissima was the superior competitor under high sediment conditions. Because glacially-influenced coastal areas often have little exposed hard substrate and predation by sea otters and sea stars on clams can provide hard substrate for kelp colonization, my third chapter examined methods for determining predation on clams by these predators without direct observation. I found that foraging pits of sea otters and sea stars could not be distinguished using quantitative measurements. In contrast, shell litter proved useful in quantifying relative foraging rates. Clam consumption by sea otters and sea stars was equal at all but one site. Collectively, my thesis chapters provide information on the effects of glacial discharge on microscopic and early kelp life stages in Alaska which can be incorporated into management practices.
    • Pacific sleeper sharks in the Northeast Pacific Ocean: relative abundance, plausible incidental exploitation rates, trophic ecology, and habitat use

      Courtney, Dean Louis; Adkison, Milo D.; Foy, Robert; Sigler, Mike; Criddle, Keith R.; DiNardo, Gerard (2017-12)
      Pacific sleeper shark relative abundance indices in the eastern Bering Sea and Gulf of Alaska were developed from sablefish longline surveys and the sustainability of a plausible range in Pacific sleeper shark incidental exploitation rates in the Gulf of Alaska was evaluated with a risk analysis using Monte Carlo simulation for use in fisheries management. A significant increase in Pacific sleeper shark relative abundance was identified in the Gulf of Alaska during the years 1989-2003. The aggregate risk of ending in an overfished condition in the Gulf of Alaska increased from 0% under a low exploitation rate scenario to 59% under a high exploitation rate scenario. Baseline information about Pacific sleeper shark trophic ecology and habitat utilization in the eastern Bering Sea and Gulf of Alaska was developed for use in ecosystem-based fishery management. Analysis of stable isotope ratios of nitrogen (δ¹⁵N) and lipid normalized carbon (δ¹³C′) identified significant geographic and ontogenetic variability in the trophic ecology of Pacific sleeper sharks in the eastern Bering Sea and Gulf of Alaska and revealed wider variability in the feeding ecology of Pacific sleeper sharks than previously obtained from diet data based on stomach contents alone. Time series analysis of Pacific sleeper shark electronic tag data from the Gulf of Alaska identified a simple autoregressive relationship governing short-term movements (hours) throughout the time series which included substantial variation in longer time period movement patterns (months) and demonstrated that statistical inference about habitat utilization could be drawn from simultaneous analysis of an entire time series depth profile (six months of data) stored on an electronic archival tag.
    • Physical environmental and biological correlates of otolith chemistry of Arctic marine fishes in the Chukchi sea

      Gleason, Christine Marie; Norcross, Brenda; Brown, Randy; Horstmann-Dehn, Larissa; Trefry, John; Christie, David (2012-08)
      Life history movement patterns in marine fishes can be determined by otolith chemistry if environmental variables are reflected in the otoliths. Arctic cod (Boreogadus Saida), Arctic staghorn sculpin (Gymnocanthus tricuspis), and Bering flounder (Hippoglossoides robustus) are abundant Arctic fishes in the Chukchi Sea with overlapping distributions. Physical environmental data, demersal fishes, bottom seawater, and sediment interface seawater samples were collected from the Chukchi Sea Offshore Monitoring in Drilling Area (COMIDA) cruise on July 30, 2009 and the Russian American Long-term Census of the Arctic (RUSALCA) cruise from September 3 to 30, 2009 in the Chukchi Sea. Magnesium (Mg), strontium (Sr), barium (Ba), and calcium (Ca) were measured with an inductively coupled plasma mass spectrometer (ICP-MS) on the most recent growth edge of otoliths and in whole fish blood, as well as Ba in bottom and sediment interface seawater. Environmental variables and fish age correlated with Arctic cod and Arctic staghorn sculpin otolith signatures while only environmental variables correlated with Bering flounder signatures. Elemental correlations were not always consistent for the variables tested among species. The complexity of this multi-element tool suggests otolith chemistry may not be useful to determine life history movement patterns of these demersal Arctic fishes in offshore waters.
    • Predatory Hymenopteran assemblages in boreal Alaska: associations with forest composition and post-fire succession

      Wenninger, Alexandria; Wagner, Diane; Hollingsworth, Teresa; Skies, Derek (2018-05)
      Predatory Hymenoptera play key roles in terrestrial foodwebs and affect ecosystem processes, but their assemblage composition and distribution among forest habitats are poorly understood. Historically, the boreal forest of interior Alaska has been characterized by a fire disturbance regime that maintains vegetation composition dominated by black spruce forest. Climate-driven changes in the boreal fire regime have begun to increase the occurrence of hardwood species in the boreal forest, including trembling aspen and Alaska paper birch. Replacement of black spruce forests with aspen forests may influence predatory hymenopteran assemblages due to differences in prey availability and extrafloral nectar provisioning. Furthermore, changes in the frequency and extent of boreal forest fires increase the proportion of forests in earlier successional stages, altering habitat structure. The primary goal of this study was to characterize predatory hymenopteran assemblages in post-fire boreal forests of interior Alaska. To investigate this, the abundance, species richness, and composition of predatory hymenopteran assemblages were compared among forests at different stages of succession that were dominated by black spruce pre-fire, but that vary in their tree species composition post-fire. Predatory hymenopterans were separated into three groups: ants, macropterous wasps, and micropterous wasps. Ant species richness and abundance were not related to forest composition, but both were significantly higher in early-successional forests than in mid-late successional forests. In contrast, macropterous wasp morphospecies richness and abundance, as well as micropterous wasp abundance, were positively related to the basal area of aspen, suggesting that aspen forests benefit macropterous and micropterous wasps, perhaps due to extrafloral nectar provisioning and the availability of greater quality prey than is provided by black spruce. Wasp assemblages did not differ between successional stages. This study is the first to characterize the influence of post-fire succession on predatory hymenopteran assemblages of the boreal forest at a large spatial scale. The results suggest that continued warming of the boreal forest will have cascading influences on the insect assemblages of boreal Alaska.
    • Quantity and quality of freshwater rearing habitat in relation to juvenile Pacific salmon abundance in the Kulukak River, Alaska

      Coleman, Jesse M.; Sutton, Trent; Zimmerman, Christian; Adkison, Milo (2012-12)
      Monitoring of freshwater habitat and its influence on stream-rearing fish is essential for recognizing and mitigating the impacts of human- and climate-induced changes. For the purposes of developing a monitoring program in the U.S. Fish and Wildlife Service Togiak National Wildlife Refuge, densities and habitat relationships of juvenile coho salmon Oncorhynchus kisutch and sockeye salmon O. nerka were estimated in two tributaries of the Kulukak River, Alaska, in July 2010. Multiple-pass depletion electrofishing was used to estimate density in a random sample of habitat units belonging to one of four categorical habitat classes. Regression methods were also used to quantify the physical habitat associations of juvenile coho and sockeye salmon density in the study areas. Densities of juvenile coho and sockeye salmon ranged from 0.22 fish-m⁻² in West Fork riffles and 0.05 fish·m⁻² East Fork riffles to 2.22 fish M⁻² and 1.32 fish-m⁻² in East Fork eddy drop zones (EDZ), respectively. The largest proportions of freshwater habitat were comprised of run (71 %) and EDZ habitats (44%) in the East Fork and West Fork, respectively. Regression coefficients for coho and sockeye salmon densities were positive with respect to proportional areas of in-stream overhanging vegetation (0.78 and 0.74, respectively), large wood (0.99 and 0.97, respectively), and undercut banks (0.99 and 0.02, respectively). Conversely, coho and sockeye salmon density was negatively related to depth ( -1.45 and -0.52, respectively) and velocity ( -2.45 and -1.67, respectively). Although substrate size was negatively related to sockeye salmon density ( -0.40), this variable had a weak positive relationship with coho salmon density (0.08). These findings suggest that EDZ habitats are important for juvenile coho and sockeye salmon during summer rearing and in-stream cover is an essential component of these rearing habitats.
    • River features associated with chinook salmon spawning habitat in Southwest Alaska

      Jallen, Deena M.; Margraf, F. Joseph; Adkison, Milo (2009-08)
      Chinook salmon (Oncorhynchus tshawytscha) is a highly valued traditional, subsistence, and commercial resource in Southwest Alaska. Stream habitat availability is a major component influencing salmon productivity. The objective of this study is to identify river features associated with spawning habitat, and describe upper and lower boundaries of chinook salmon spawning on the Tuluksak River. River distances, elevation, salmon locations, spawning sites, and habitat observations were collected along 75 river kilometers of the Tuluksak River primarily within the Yukon Delta National Wildlife Refuge. Habitat and salmon observations were grouped into strata along the length of the river for comparison and analysis. Chinook salmon were observed spawning in the upper 45 river kilometers of the study area. Map-based observations of elevation and channel sinuosity correlate better with chinook salmon spawning than in stream habitat measurements along the Tuluksak River. The upper boundary of chinook salmon spawning in the Tuluksak River was outside of our study area. The lower boundary for chinook salmon spawning habitat on similar rivers might be determined by examining elevation, sinuosity, and channel features from remote images or maps prior to conducting field studies.
    • Using multispectral aerial imagery and GIS-based approaches to quantify juvenile salmon rearing habitat in the Kulukak River, Alaska

      Woll, Christine; Sutton, Trent; Prakash, Anupma; McPhee, Megan (2012-05)
      Monitoring the quality and quantity of freshwater rearing habitat for Pacific salmon Oncorhynchus spp. is essential for maintaining stocks of these species. Because field-based habitat monitoring in remote areas can be expensive, time-consuming, and/or subjective, new methods are desired. The objectives of this study were (1) to develop methods for using multispectral aerial imagery to classify juvenile rearing habitat and determine the accuracy of these methods and (2) to use these methods to quantify and map juvenile salmon habitat characteristics in two study areas in the Kulukak River, Alaska. I demonstrated that a decision-based fusion approach using images acquired in the visible, near-infrared, and thermal-infrared regions classified habitat classes important for juvenile salmon with accuracies of 82.5% and 67.5% in the respective study areas. In addition, I quantified and mapped habitat variables often used in juvenile salmon studies on several scales and created habitat-suitability maps for coho salmon O. kisutch, demonstrating that both my study areas differed in habitat quantity and quality and are most likely low-quality rearing areas. This study demonstrates that airborne images can be used to determine the quality and quantity of juvenile Pacific salmon rearing habitat in small streams and thus decision support in fisheries management.
    • Using remote sensing, occupancy estimation, and fine-scale habitat characterization to evaluate fall chum salmon (Oncorhynchus keta) spawning habitat usage in Arctic Alaska

      Clawson, Chelsea M.; Falke, Jeffrey; Westley, Peter; Prakash, Anupma; Martin, Aaron (2017-08)
      Groundwater upwellings provide stable temperatures for overwinter salmon embryo development and this process may be particularly important in cold, braided, gravel-bed Arctic rivers where rivers may freeze solid in the absence of upwellings. Aerial counts and remote sensing were used during 2013-2015 to estimate fall chum salmon (Oncorhynchus keta) spawner abundance states (e.g., low or high), classify river segments by geomorphic channel type (primary, flood, and spring), and map thermal variability along a 25.4 km stretch of the Chandalar River in interior Alaska. Additionally, I used on-the-ground examination of fine scale variation in physical habitat characteristics at 11 representative sites to characterize habitat variability, placed temperature loggers to assess overwinter thermal conditions in redds, and used a developmental model to predict hatching and emergence timing given known spawning dates and incubation temperatures. I delineated 330 unique river segments (mean length = 536 m) and used a multi-season multistate occupancy model to estimate detectability, occupancy, and local colonization and extinction rates. Triplicate surveys performed in 2014 allowed me to estimate detectability and the influence of observer bias. I found that detectability did not vary by observer, channel type, or segment length, but was better for high abundance (0.717 ± 0.06 SE) relative to low abundance (0.367 ± 0.07 SE) aggregations. After correcting for imperfect detection, the proportion of segments occupied by spawning fall chum salmon was highest in 2014 (0.41 ± 0.04 SE), relative to 2013 (0.23 ± 0.04) and 2015 (0.23 ± 0.04). Transition probabilities indicated unoccupied segments were likely to remain so from year to year (2013→2014 = 0.67; 2014→2015 = 0.90), but low abundance spawning segments were dynamic and rarely remained in that state. One-third of high abundance sites remained so, indicating the presence of high quality spawning habitat. Mean segment temperatures ranged from -0.5 to 4.4°C, and occupancy varied positively with temperature. I predicted a 50% probability of occupancy in segments with temperatures of 3°C. With my on-the-ground work, I found that habitat characteristics varied among the three channel types, with most significant differences between main channel and off-channel habitats. Dissolved oxygen and pH decreased with increasing temperature, and conductivity increased with temperature. Predicted hatching and emergence timing ranged from 78 and 176 days (December 11th and March 18th) to 288 and 317 days (July 8th and August 6th), respectively, post-spawning, and were highly variable within sites and among channel types owing to high habitat thermal heterogeneity. Because the Chandalar River supports 30% of the fall chum salmon run in the Yukon River Basin, information such as provided by this study will be critical to allow resource managers to better understand the effects of future climate and anthropogenic change in the region.
    • Waterbird distribution and habitat in the Prairie Pothole Region, U.S.A.

      Steen, Valerie (2010-12)
      The Prairie Pothole Region (PPR) of north-central North America provides some of the most critical wetland habitat continent-wide to waterbirds. Agricultural conversion has resulted in widespread wetland drainage. Furthermore, climate change projections indicate a drier future, which will alter remaining wetland habitats. I evaluated Black Tern (Chlidonias niger) habitat selection and the potential impacts of climate change on the distribution of waterbird species. To examine Black Tern habitat selection, I surveyed 589 wetlands in North and South Dakota in 2008-09, then created multivariate habitat models. I documented breeding at 5% and foraging at 17% of wetlands surveyed, and found local variables were more important predictors of use than landscape variables, evidence for differential selection of wetlands where breeding and foraging occurred, and evidence fora more limited role of area sensitivity (wetland size). To examine the potential effects of climate change, I created models relating occurrence of five waterbird species to climate and wetland variables for the U.S. PPR. Projected range reductions were 28 to 99%, with an average of 64% for all species. Models also predicted that, given even wetland density, the best areas to conserve under climate change are Northern North Dakota and Minnesota.
    • Winter habitat of arctic grayling in an interior Alaska stream

      Lubinski, Brian R. (1995-05)
      Placer mining and the lack of information on winter ecology of Arctic grayling Thymallus arcticus. has raised concern for this popular sportfish. A study was designed to validate aerial radio telemetry data and to locate and describe overwinter areas (OWA) of Arctic grayling in Beaver Creek, Alaska. Reliance on aerial data alone resulted in overestimation of survival and misidentification of 14 of 26 designated OWAs. Twenty-one Arctic grayling were tracked downstream 12-58 km to 12 OWAs spanning a 31-km section of Beaver Creek. Radio-tagged and untagged Arctic grayling occupied areas with ice thickness of 0.4-1.4 m overlying 0.06-0.52 m of water, flowing at 0.03-0.56 m/s. During winter, discharge, cross-sectional area, velocities, and water width in four OWAs decreased until late March; then, cross-sectional area increased due to an increase in discharge that pushed the ice upward. Adult Arctic grayling overwintered downstream of habitat disturbances, and occupied much shallower winter habitats than expected.