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College of Fisheries and Ocean Sciences (CFOS)
The College of Fisheries and Ocean Sciences educates and inspires the next generation of world-class aquatic ecosystem scientists. -
Office of the Provost
The University of Alaska Fairbanks Provost is responsible for providing overall leadership, coordination and direction to UAF research and scholarly activities and graduate studies. -
School of Natural Resources and Agricultural Sciences (SNRAS)
As the primary land-grant component of the university, SNRAS administers a variety of programs and engages in cooperative efforts with federal, state, and borough governments and agencies. -
UAF Graduate School
University of Alaska Fairbanks Graduate School -
Undergraduate Research and Scholarly Activity
At the University of Alaska Fairbanks, the Office of Undergraduate Research and Scholarly Activity (URSA) supports, develops and institutionalizes UAF's diverse and robust programs of undergraduate research and creative ...
Recent Submissions
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EVALUATING DRONE TECHNOLOGY TO IDENTIFY ICE CHANGES THAT CAN CAUSE ICE-ROAD HAZARDSIce roads in Alaska, a form that connects people during the winter months, enable the importing of critical goods and accessibility to medical services. These ice roads span 100 miles or more and are subject to spatial and temporal safety variability during the shoulder seasons and unseasonal warm events of above-freezing temperatures. In this work, we explore using an unmanned aircraft system (UAS) coupled with a ground penetrating radar (GPR) to inspect ice thickness safety and the presence of subsnow liquid overflow, common during winter. We compared our UAS-based GPR with ground-based GPR and nearby ice coring. We found the UAS-based GPR biased compared to the ice cores and the ground-based GPR. Nonetheless, when accounting for this bias, the UAS-based GPR had an RMSE of 5 cm for an ice thickness of 20 to 60 cm. More work is needed to understand the root cause of the UAS-based GPR for measuring ice thickness. The UAS-based GPR also effectively mapped subsnow liquid overflow by measuring the radar return amplitude, which is particularly strong when reflecting between the snow and water layers. Coupling UAS and GPR technology has great promise in conducting ice river safety assessments from a safe location. Still, more work must be done to understand the data’s bias.
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Spawning stocks and juvenile summer habitat of rainbow trout and steelhead, Gulkana River, AlaskaThe Gulkana River supports the northernmost population of steelhead and rainbow trout Oncorhynchus mykiss in North America. The summer habitat of Gulkana River juvenile trout (i.e., steelhead and rainbow trout) was identified and described. Analysis of geomorphological features of stream reaches (stream entrenchment, bankfull width-to-depth ratio, sinuosity, channel material, and slope) in relation to differential use of habitat by juvenile trout indicated a strong preference for type C reaches (predominately riffle/run habitat) over type E reaches (predominately slow run habitat). A comparison of micro-habitats (riffle, run, pool, slow run) within those same reaches and distribution of juvenile trout indicated a preference for riffle and run habitat. Most type C reaches in the Mainstem were sparsely populated by juveniles throughout summer. The Middle Fork was devoid of juveniles in early summer. In mid- and late summer, coinciding with the arrival of spawning chinook O. tshawytscha and sockeye salmon O. nerka, most riffle/run reaches in the Middle Fork were occupied by juvenile trout. The steelhead spawning population has declined from an estimated 200-1,000 fish two decades ago to 20-50 fish during this study (1993-1995). Rainbow trout stocks are also apparently low. Monitoring of Copper River fisheries and Gulkana spawning populations and an investigation into other steelhead spawning populations in the Copper River basin are recommended
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Alaska Earthquake Center Quarterly Technical Report October-December 2024This series of technical quarterly reports from the Alaska Earthquake Center (AEC) includes detailed summaries and updates on Alaska seismicity, the AEC seismic network and stations, fieldwork, our online presence, public outreach, and lists publications and presentations by AEC staff. Multiple AEC staff members contributed to this report.
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Lake productivity indices as estimators of carrying capacity for burbot and northern pike in Interior AlaskaTwo Alaska sport fish species, burbot and northern pike, were used to test the ability to estimate carrying capacity of fishes based on biotic and abiotic indices of lake productivity. Understanding the quantitative relationships between the potential fish productivity of freshwater lakes and physical, biological, or chemical characteristics could provide models sufficient for calculating a timely prediction of carrying capacity to evaluate the population status. This would provide a technique for allocating limited resources for fishery stock assessment as an aide in resource management of sport fisheries. The lakes covered in the study lie in an area spanning West 151°--142°/North 64°30ʹ--61°52ʹ. They are Fielding Lake, George Lake, Glacier Lake, Harding Lake, Hudson Lake, Jatahmund Lake, Lake Louise, Landlocked Tangle Lake, Moose Lake, Paxson Lake, Sevenmile Lake, T Lake, Tolsona Lake, Volkmar Lake, and West Twin Lake.
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Seasonal habitat relationships of adult female deer on Kodiak Island, AlaskaMovements of adult female deer (Odocoileus hemionus sitkensis) were monitored using radio-collars (n = 21) in a region lacking old-growth conifer forest on Kodiak Island, Alaska, from 17 July 1990 to 8 July 1991. Mean distance between seasonal ranges for 7 deer that migrated from the study area during winter was 22 km (SD = 10.2 km), whereas < 5 km separated seasonal ranges of 14 deer that remained in the study area throughout the year. Mean movement date to winter range was 30 October (SD = 38 days), and to summer range, 29 May (SD = 18 days). Overall habitat use differed significantly (P < 0.001) between seasons. Habitats used more than available (P ≤ 0.01) were tall shrub closed in summer and tall shrub open in winter. Using the 95% adaptive kernel method (Worton 1989), mean summer home range (454 ha, n = 11, range 134 - 819 ha, SD = 227 ha) was larger (P < 0.001)than the mean winter home range (107 ha, n = 9, range 67-217 ha, SD = 56 ha).
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Plant architecture and forage selection by mooseThe effects of plant architecture on browse selection and the extent of use of Salix alaxensis and Salix plantifolia by moose foraging in winter in Interior Alaska were studied during 1997 and 1998. Three sampling techniques were employed to estimate forage availability and utilization. Sampling forage availability prior to use (in autumn) provided the best estimates of forage use in spring. In Salix plantifolia, selection of current annual growth (CAG) twigs was significantly related to basal diameter of CAG, diameter of nearest neighbor, distance to nearest neighbor, and number of leaders per cluster. In contrast, CAG selection in Salix alaxensis was related only to basal diameter. The proportion of CAG biomass removed from stems of either species was not related to any measured plant architecture variables. Because plant architecture affects browse use by moose, it is an important factor in determining food availability, and thereby in assessing moose habitat
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Comparative habitat and diet selection of muskoxen and reindeer on the Seward Peninsula, western AlaskaFactors influencing choice of feeding sites, cratering microsites and diets of reindeer (Rangifer tarandus) and reintroduced muskoxen (Ovibos moschatos) were examined on the Seward Peninsula, western Alaska, during late winters of 1996 and 1997. Both ungulates foraged primarily in upland habitats with low snow depth, relatively high occurrence of lichens and low occurrence of graminoids. Both selected against snow depth when choosing feeding sites and against snow depth and hardness when selecting cratering areas within feeding sites. Diet selection differed between species. Reindeer selected mainly lichens while muskoxen selected more sedge and moss. Few behavioral interactions between species were observed, and none seemed to result in displacement of either species. Despite similar use of late winter feeding sites, competition between muskoxen and reindeer in the study area is not likely at the moment, but may occur if severe snow conditions or increasing densities of either species restrict available winter habitat
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Estimation of aging accuracy and precision, growth, and sustained yield of coastal cutthroat trout in Southeast AlaskaThis study was designed to validate and estimate accuracy and precision of ages determined from scales sampled from coastal Cutthroat trout Oncorhynchus clarki clarki in Southeast Alaska; to model growth of these fish; and to evaluate the sensitivity of sustained yield estimates to aging error. Cutthroat trout scales sampled in Southeast Alaska did not always form an annulus during the first year, although the number of circuli up to the first apparent annulus was a good indicator that one was missing. Reader error generally resulted in significant underaging of older fish from scales. However, aging error models developed in this study significantly improved the accuracy of ages estimated from scales. Growth of cutthroat trout was best described by a Gompertz growth curve and was significantly different between the populations studied. Underaging of cutthroat trout resulted in underestimates of optimum levels of fishing mortality and yield.
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Distribution and behavior of barren-ground caribou in relation to weather and parasitic insectsRelationships between weather and the activity of mosquitoes (Culicidae) and oestrid flies (Oestridae), and responses by caribou (Rangifer tarandus) to insect harassment, were examined near Milne Point, Alaska. Weather conditions were usually unfavorable for insects within 20 km of the Beaufort Sea, and were least favorable within 1-3 km of the eoast. Weather affected the occurrence more than the level of insect activity. Mosquitoes were rarely active within 1 km of the coast; maritime weather conditions had little effect on oestrids. Weather conditions and insect activity were more variable through time than through space： this necessitated models predicting: (1) the presence of insects, and (2) levels of insect activity when insects were present. Insect harassment caused caribou to travel rapidly to coastal areas at the expense of feeding and lying, and form large, mixed groups. Insect activity was most highly correlated with caribou rate of travel and behavior.
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Impact of the COVID-19 Pandemic on Travel Mode Choices and Fatal Crash RatesThe COVID-19 pandemic caused unprecedented disruptions to human mobility and transportation systems worldwide, significantly altering travel behavior and mode choices. This study investigates these changes within the Pacific Northwest region of the United States, encompassing a mix of urban and rural contexts with diverse socio- demographic characteristics. Using survey data from 807 respondents, we analyze transportation patterns before and during the pandemic, focusing on shifts in mode shares and probabilities of switching travel modes. The analysis incorporates McNemar’s test, logistic regression, and latent class analysis (LCA) to evaluate the extent of these shifts and identify key influencing factors. The results reveal a substantial reduction in public transport usage, reflecting heightened concerns over health risks and limited operational capacity during the pandemic. In contrast, there was a notable increase in the use of private vehicles and active transportation modes, such as walking and cycling. Demographic variables, including age, income, employment status, and gender, played significant roles in shaping travel behavior, with younger and lower-income individuals exhibiting higher probabilities of mode change. The latent class analysis highlighted distinct behavioral clusters, indicating that travel behavior responses were not uniform across populations. A logistic regression model further underscored the importance of pre-pandemic travel habits, socio-economic conditions, and pandemic-related concerns in influencing mode choice decisions. Additionally, traffic safety outcomes showed notable variations, with overall crash rates decreasing during the lockdowns but fatality rates rising due to riskier driving behaviors, such as speeding on roads. Crash patterns varied across urban and rural areas, with urban crashes experiencing a slight decline in proportion, while rural crashes increased.
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2024 Alaska Seismicity SummaryThe Alaska Earthquake Center reported 39,836 seismic events in Alaska and neighboring regions in 2024. The largest earthquakes were two magnitude 6.3 events that were part of a swarm of M6 events on December 8-9 in the Andreanof Islands region of Alaska. The first occurred on December 8 at 19:57:07 UTC, and the second occurred at 00:15:30 on December 9, followed by an M6.1 23 minutes later. Other strong earthquakes include two M6.0 events, one on May 19 and one on July 19, both south of Yunaska Island in the Islands of Four Mountains region of the Aleutians, and the strongest mainland earthquake, an M5.9, off the coast of Port Alexander in Southeast Alaska on January 12. We continued to monitor the 2020 M7.8 Simeonof sequence, but all other previous sequences and swarms have dropped below one event per day and are no longer being tracked. Numerous short-lived swarms occurred in 2024 and will be discussed below.
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Data Submission Package for Manuscript 'Alaska as a failed socio and ecological state? Some supporting evidence from the absence of carnivorous plant trait conservation using open access and ensemble model predictions'Plants with carnivorous traits are of great importance. However, it is globally noticed that without effective conservation, a declining number of suitable habitats, and the wide destruction of currently realized niches, their future does not appear bright. In a region that had all possibilities to “get things right” upon its statehood being granted in 1959, Alaska has, up to the present moment, consistently fallen short in stabilizing an effective conservation system for this group of plant traits and its habitats. Coupled with many other socio-ecological issues that persist from the colonial and industrial past and worsen over time, as well as the rise of new issues such as global climate change and “the great acceleration,” Alaska presents virtually all the typical indicators of a failed socio-ecological state (as a term used by The World Bank). For a wider assessment, here we compiled all Open Access data in the public realm related to eight carnivorous plant species in Alaska and overlaid them for an assessment with nine predictor layers. Beyond raw data, we developed ensemble models serving the purpose of indicating generalized hotspots and coldspots of plants with carnivorous traits, also using citizen-science occurrence data. Further, we analyzed the predicted occurrence with the underlaying land ownership/use types as well as mining claims as an example of a leading industrial activity. Alaska actually hosts the majority of the US National Park System, but we find the majority of carnivorous plants located outside, and a higher predicted occurrence within officially designated mining areas than outside. In our assessment, we see no relevant policy, vision, efficient action, or principles of strategic conservation management applied to plants and their traits, specifically carnivorous plants in Alaska and its leadership. Judged by the major socio-ecological metrics, it confirms evidence that Alaska does not present basic performance metrics of good natural resource management, and thus it would meet the definition of a failed state.
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Radiowave scattering structure in the disturbed auroral ionosphere : some measured propertiesA technique for quantitative description of radiowave scattering structure in the disturbed auroral ionosphere is developed in this work. Application is made by means of multi-spacing interferometric observations of a radio star. The work is based on the observed fact that sufficient scattering causes a measurable decrease in correlation of output voltages from neighboring antennas. Such correlation decreases are called visibility fades herein and have been called long-duration fades and radio-star fadeouts by other workers. Random noise theory is employed, and it is assumed that the angular spectrum of the source, as received at the ground after scattering, is randomly phased. However, the usual assumption of a Gaussian autocorrelation function to describe the scattering structure is circumvented, and provision is made for the existence of quasi-periodic structure. Further, the usual assumption of weak (single) or strong (multiple) scatter is avoided. The statistical characteristics of amplitude, phase, and complex signal are developed for the general case of arbitrary degree of scatter, using a numerical method. The technique is applied to observations with phase-switch and phase-sweep interferometers, yielding two important parameters of the received wavefront, the coherence ratio and the wavefront auto-correlation function. The coherence ratio is defined as the ratio of nonscattered to scattered flux received from the source. The wavefront autocorrelation function is defined as the spatial autocorrelation function of the scattered portion of the (complex) wavefront. Two quantities which describe the ionospheric scattering region are obtained from the coherence ratio and wavefront autocorrelation function. First, the optical depth of the region (considered as a purely scattering medium) is determined from the coherence ratio. Second, the ionospheric structural autocorrelation function is established jointly from the wavefront autocorrelation function and the optical depth, yielding a statistical description of the average size and idealized shape of the ion-density irregularities which produced the scattering. Forty-nine visibility fades observed at College, Alaska, between November of 1964 and February of 1966, inclusive, are analyzed. A majority of the fades revealed optical depths in excess of unity at 68 MHz. Optical depth is numerically equal to mean-square fluctuation in radio-frequency phase across a plane at the base of the scattering region, so the fades were characterized by rms phase deviations in excess of one radian at 68 MHz. An approximately inverse-square dependence of optical depth on frequency was obtained from simultaneous observations at 68, 137, and 223 MHz. At 68 MHz, tri-spacing observations were carried out on east-west baselines of 110 meters (25 λ), 220 meters (50 λ), and 330 meters (75 λ). The observations seldom were consistent with the demands of a Gaussian autocorrelation function, as is commonly assumed. Rather, the disturbed auroral ionosphere displays evidence of quasi-periodic structure in the dimensional range of tens and hundreds of meters. The structure observed is comparable in size to auroral rays. While most of the observations were consistent with the assumption of a randomly phased angular spectrum, a significant minority was not. Quantitative results could not be obtained in these instances, and they imply the existence of highly developed quasi-periodicity. Theoretical work is needed to bridge the gap between quasi-periodic structure in the sense of random-noise theory and strict periodicity. Narrow-beam photometers were mounted on one of the interferometer antennas tracking the radio star. Auroral luminosity was recorded along the line of sight during 100% of the visibility fades which occurred at night under clear-sky conditions and during many night-time fades which occurred under cloudy conditions Thus, VHF radio-star visibility fades in the auroral zone result from scattering by irregularities directly associated with auroral forms, at least at night.
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School Travel Behaviors in Rural Communities: Pandemic-Related ImpactsThe global pandemic, which started around early 2020, significantly disrupted life for many families, and the trip to and from school was not immune to these disruptions. Parents and children alike made travel adjustments depending on their preferences with regard to personal health and safety, social distancing, and aversion to risk. Each school district and individual school also made decisions with regard to in-person or remote learning during this period of uncertainty. In this study, the research team examines how the pandemic affected school transportation for hundreds of families across the Pacific Northwest. An online survey was developed and administered with the help of Qualtrics, an experience management company. Over 600 responses were gathered to assess school transportation-related travel decisions. In addition to collecting demographic data about the respondents, the survey also asked about travel mode choices and characteristics of the trip to and from school. The collective results were then analyzed to determine which factors directly contributed to pandemic-related changes in travel behavior. The study concluded that the demographic factors of parent education level, household income, and age of child were all statistically significant variables that affected behavioral change, though the place of household residence, whether rural or urban, was determined to be an insignificant variable. Additionally, common travel assumptions associated with rural students, when compared with urban students, were confirmed. These factors included a greater reliance on a yellow school bus and lesser availability of critical infrastructure.
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Nesting habitat relationships of four species of alcids at Fish Island, AlaskaTufted Puffins, Horned Puffins, Parakeet Auklets, and Pigeon Guillemots were studied at Fish Island, Alaska, 59°52, N, 147°25, W, to determine if nesting habitat relationships indicated nest separa- tion or competition. The timing of early stages of breeding and daily activity patterns overlapped broadly among all species. Aggressive interactions occurred among all species. Tufted Puffins nested in cliff edges and grassy slopes; all species used rocky slopes and cliff faces. Tufted Puffin nests in rocks differed from Pigeon Guillemot and Parakeet Auklet nests in having larger entrance height and area, and they were placed farther from the high tide line. These dif- ferences related to body size and take-off ability, and may be indica- tions of past competition for nest sites. Interspecific interactions and site use by more than one species indicated some competition may have occurred for certain sites. Overall, most evidence indicated competition had little influence on nest site use among species.
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Data Submission Package for Manuscript 'Using Machine Learning, the Cloud, Big Data, Citizen-science, and the world’s largest set of environmental predictors towards proposing modern add-ons to improve conservation management plans for squirrel species in Alaska and Indigenous lands'Context. Squirrel species in Alaska generally lack thorough conservation management plans, and they are actively hunted with no bag limits, closed seasons, or any other restrictions. This indicates a laissez-faire approach to Alaskan squirrel conservation management. Aims. In an attempt to improve this current situation, we employ an ensemble of machine-learning algorithms as proposed improvement add-ons to the traditional components of conservation management plans toward a more state-of-the-art approach to squirrel conservation. Methods. We combined the Machine Learning algorithms TreeNet, CART, Random Forest, and Maxent with over 200 environmental and socio-economic predictors for the ensemble Super Species Distribution Models. These ensemble models were carried out for all squirrel species individually occurring in Alaska and a 600 km buffer area and two assemblage models combined: a) all species currently occurring only in Alaska and b) all species occurring in Alaska and the 600km buffer area. Key results. Most predicted distribution hotspots for squirrels in Alaska and the 600 km buffer area were observed near road and river systems (close to human activities) and the last glacial maximum refugia. Conclusions & Implications. Applying a machine learning ensemble distribution modeling framework to conservation management plans can add valuable science-based insights to better understand the landscape and species to be managed. This can also be highly valuable for lands not directly managed by conventional agencies, e.g., land managed by the military or Native communities.
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Data Submission Package for Manuscript 'Progress on the world's primate hotspots and coldspots: Modeling ensemble Super SDMs in cloud-computers based on digital citizen-science Big Data and 200+ predictors for more sustainable conservation planning'2Describing where distribution hotspots and coldspots are located with certainty is crucial for any science-based species management and governance. Thus, here we created the world’s first Super Species Distribution Models (SDMs) including all primate species and the best-available predictor set. These Super SDMs are conducted using modern Machine Learning ensembles like Maxent, TreeNet, RandomForest, CART, CART Boosting and Bagging, and MARS with the utilization of cloud supercomputers (as an add-on option for more powerful models). For the global cold/ hotspot models, we obtained global distribution data from www.GBIF.org (approx. 420,000 raw occurrence records) and utilized the world’s largest environmental predictor set of 201 layers. For this analysis, all occurrences have been merged into one multi-species (400+ species) pixel-based analysis. We quantified the global primate hotspots for Central and Northern South America, West Africa, East Africa, Southeast Asia, Central Asia, and Southern Africa. The global primate coldspots are Antarctica, the Arctic, most temperate regions, and Oceania past the Wallace line. We additionally described all these modeled hotspots/coldspots and discussed reasons for a quantified understanding of where the world’s primates occur (or not). This shows us where the focus for most future research and conservation management efforts should be, using state-of-the-art digital data indication tools with reason. Those areas should be considered of the highest conservation priority, ideally following ‘no killing zones’ and sustainable land stewardship approaches if primates are to have a chance of survival.
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Data Submission Package for Manuscript 'Progress on the world's primate hotspots and coldspots: Modeling ensemble Super SDMs in cloud-computers based on digital citizen-science Big Data and 200+ predictors for more sustainable conservation planning'Describing where distribution hotspots and coldspots are located with certainty is crucial for any science-based species management and governance. Thus, here we created the world’s first Super Species Distribution Models (SDMs) including all primate species and the best-available predictor set. These Super SDMs are conducted using modern Machine Learning ensembles like Maxent, TreeNet, RandomForest, CART, CART Boosting and Bagging, and MARS with the utilization of cloud supercomputers (as an add-on option for more powerful models). For the global cold/ hotspot models, we obtained global distribution data from www.GBIF.org (approx. 420,000 raw occurrence records) and utilized the world’s largest environmental predictor set of 201 layers. For this analysis, all occurrences have been merged into one multi-species (400+ species) pixel-based analysis. We quantified the global primate hotspots for Central and Northern South America, West Africa, East Africa, Southeast Asia, Central Asia, and Southern Africa. The global primate coldspots are Antarctica, the Arctic, most temperate regions, and Oceania past the Wallace line. We additionally described all these modeled hotspots/coldspots and discussed reasons for a quantified understanding of where the world’s primates occur (or not). This shows us where the focus for most future research and conservation management efforts should be, using state-of-the-art digital data indication tools with reason. Those areas should be considered of the highest conservation priority, ideally following ‘no killing zones’ and sustainable land stewardship approaches if primates are to have a chance of survival.
