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Item Blackfoot traditional knowledge, bison drive lines, and geospatial analysis(Montana State University - Bozeman, College of Letters & Science, 2024) Edmo, Kendall Rae; Chairperson, Graduate Committee: David B. McWethy; This is a manuscript style paper that includes co-authored chapters.Bison drive lines provide material evidence of ancestral Blackfoot practices. The spatial dimensions of drive lines highlight a sophisticated understanding of bison-environment interactions and the strategic use of geographic landforms and environmental features to maintain a critical lifeway. Here we examine broad-scale landscape use patterns among prehistoric Blackfoot bison hunters on the Northwestern Plains through an analysis of a network of drive lines in traditional Blackfoot territory (US) using Geographic Information Systems (GIS) and previous archaeological and anthropological research. The findings of this study show that ancestral Blackfoot designed bison drive lines to be positioned in proximity to key landscape resources including water, forested areas, and wetlands and kettle lakes. This study builds on previous research that applies an Indigenous archaeological framework that incorporates ethnohistoric narratives and traditional knowledge to provide important context for understanding the relationship between ancestral Blackfoot, bison, and the cultural landscape. Examining the relationship between drive lines and landscape features helps advance our understanding of the Blackfoot knowledge system that has adapted and endured for millennia.Item Rethinking water conflict and cooperation: a re-analysis of interviews in Montana and an example study from the Big Hole River watershed(Montana State University - Bozeman, College of Letters & Science, 2024) Bjorklund, Erin Nicole; Chairperson, Graduate Committee: Sarah P. Church; This is a manuscript style paper that includes co-authored chapters.Climate change heightens the supply and demand imbalance for freshwater, increasing the potential for conflict between water users. However, conflict is not the only outcome, as water demands can also create space for cooperation. The Basins at Risk (BAR) scale is one of the most prominent numerical measurements for analyzing the level of conflict or cooperation in freshwater-related events reported in public news sources. However, few studies in the U.S. West and none within Montana have utilized this method and little has been done to investigate alternative applications of the BAR scale beyond news event analysis. Therefore, this study examines 1) water conflict and cooperation trends in Montana and 2) how interview data can contribute to nuanced understandings of water conflict and cooperation. The intensity and type of issue for water events in Montana were cataloged and analyzed in a re-analysis of 63 interviews conducted for the Montana Drought Vulnerability Assessment. Results revealed that from the perspective of Montanan water stakeholders, cooperation over water resources outweighs conflict, and low-intensity conflictive and cooperative events are more prominent. The re-analysis results informed the selection of an example study utilizing the BAR scale to analyze event data (n=314) and primary interviews (n=11) collected in the Big Hole Watershed, Montana. Event data was sampled from 7 Montana news sources between the years 2007 and 2023. Primary interviews were conducted in February, March, and April 2024 with a variety of stakeholders in the Big Hole River Watershed (e.g., anglers, ranchers, fishing guides, Big Hole Watershed Committee board members, Fish, Wildlife and Parks). These data show the value of including primary interviews in a study utilizing the BAR scale. Moreover, results from this study can help researchers and resource managers monitor and identify water conflict and cooperation, by showing a nuanced understanding of conflict and cooperation.Item Reconstructing large herbivore abundance and environmental interactions in postglacial North America(Montana State University - Bozeman, College of Letters & Science, 2023) Wendt IV, John Arthur Frederic; Chairperson, Graduate Committee: David B. McWethy; This is a manuscript style paper that includes co-authored chapters.Large herbivores drive critical ecological processes, yet their long-term dynamics and effects are poorly understood due to the limitations of existing paleoherbivore proxies. To address these shortcomings, long-term records of paleoherbivores were constructed by (i) applying new analytical techniques to existing bison fossil datasets; and (ii) examining fecal steroid data that characterize temporal changes in ungulate abundance and community composition. These paleoherbivore reconstructions were analyzed in relation to their environmental contexts to better understand herbivore-ecosystem interactions through time in three separate studies: First, spatiotemporal changes in postglacial bison distribution and abundance in North America were examined by summarizing fossil bison observations. Bison observations were compared with simulated climate variables in a distribution modeling framework to project probable bison distributions in 1000-year intervals from the Last Glacial Maximum to present in light of changing climatic drivers over time. Since the Bolling-Allerod Interstadial (14.7-12.9 ka) the geographic distribution of bison is primarily explained by seasonal temperature patterns. Second, Holocene records of bison abundance were compared to paleofire reconstructions spanning the midcontinental moisture gradient to determine the relative dominance of herbivores and fire as biomass consumers. Bison dominated biomass consumption in dry settings whereas fire dominated consumption in wetter environments. Historical distributions of herbivory and burning resemble those of Sub-Saharan Africa, suggesting a degree of generality in the feedbacks and interactions that regulate long-term consumer dynamics. Third, the utility of fecal steroids in lake sediments for reconstructing past herbivore abundance and identity was tested by (i) characterizing the fecal steroid signatures of key North American ungulates, (ii) comparing these signatures with multiproxy data preserved in lake sediments from the Yellowstone Northern Range, and (iii) comparing influxes of fecal steroids over time to historical records of ungulate biomass and use. Bison and/or elk were abundant at Buffalo Ford Lake over the past c. 2300 years. Ungulate densities in the watershed were highest in the early 20 th century and likely contributed to decreases in forage taxa and possibly increased lake production. These results demonstrate long-term ecological impacts of herbivores and highlight opportunities for continued development of paleoherbivore proxies.Item When and where does irrigation water originate? Leveraging stable water isotopes and synthetic aperture radar to assess the complex hydrology of a snow-dominated catchment in southwestern Montana(Montana State University - Bozeman, College of Letters & Science, 2023) Rickenbaugh, Eliza Apple; Chairperson, Graduate Committee: Eric A. Sproles; This is a manuscript style paper that includes co-authored chapters.Many agricultural regions around the world rely on water stored in mountainous snowpacks for irrigation supply. Consequently, our current and future ability to produce food is threatened by more frequent, severe, and extended snow droughts. As these snow droughts intensify, water resource managers will need more efficient and accurate methods to characterize the snowmelt cycle and forecast water availability. Focusing on a montane headwater catchment in Southwestern Montana (423 km 2 in area, between 1465 m to 3270 m in elevation), we integrate in-situ and remotely sensed data to assess the relative contributions of groundwater and the current season's snowmelt to irrigation supply for water year (WY, Oct 1 - Sep 30) 2023. To understand the period over which snow contributes to stream water in this catchment, we analyze backscatter data from Sentinel-1 Synthetic Aperture Radar (SAR). This provides approximate dates of snowmelt runoff onset at 10 m resolution every twelve days. We find that the median date of snowmelt runoff onset in WY 2023 in this catchment was April 20, six days later than the 7-year median date of snowmelt runoff onset. To assess relative contributions to streamflow we compare stable water isotope ratios (deltaH2 and deltaO18) from biweekly samples of stream water at low elevations against monthly samples of snow and groundwater. Samples range in elevation from 1,475 m to 2,555 m. We find that stream water below the highest diversion point is predominantly composed of groundwater. Results demonstrate alignment between two disparate approaches for estimating temporal trends in snowpack contribution to stream flow. While our work focuses on a catchment in Montana, the efforts and approaches used are potentially applicable globally for agricultural regions that rely on snowmelt for irrigation.Item A framework for the quantitative assessment of new data streams in avalanche forecasting(Montana State University - Bozeman, College of Letters & Science, 2023) Haddad, Alexander Sean; Co-chairs, Graduate Committee: Eric A. Sproles and Jordy HendrikxData used by avalanche forecasters are typically collected using weather stations, manual field-based observations (e.g., avalanche events, snow profiles, stability tests, personal observations, public observations, etc.) and weather forecasts ("traditional observations"). Today, snow cover observations can be delivered via remote sensing (e.g., satellite data, UAV, TLS, time-lapse camera etc.). Forecasting operations can also use statistical forecasting, weather models, and physical modeling to support decisions. This paper presents a framework and methodology to quantify the impact these new, complex data streams have on the formulation of, and associated uncertainty of, avalanche forecasting. We use data from a case study in Norway. Avalanche forecasters in Norway assessed size (D), likelihood, avalanche problem, and hazard level for a highway corridor in Grasdalen, Stryn Norway. The control groups were given access to traditional observations. The experimental groups were given access to the same traditional data, but also near-real-time snow surface LiDAR data ("RS+"). In case study one the RS+ (n=10) consensus findings were a hazard level two steps lower than the control group (n=10). In case study two the traditional (n=10) and RS+ groups' (n=7) consensus findings assessed the northeastern avalanche path at the same hazard level. Assessing the southwestern slide path, the traditional group (n=10) and RS+ group (n=9) had the same consensus finding for hazard level. In 2 of 3 case studies, the RS+ groups had fewer selections for size, likelihood, and avalanche problem which indicates reduced uncertainty in their forecasts. Throughout the 2022-2023 winter season Norwegian Public Roads Administration avalanche forecasters performed a real-time experiment throughout the season - with and without additional RS+ data when forecasting. They agreed on hazard level in 6 of 10 forecasts. In the other 4 forecasts, RS+ forecasters assessed the hazard level higher than traditional data forecasts. When RS+ data reveals aspects of conditions that traditional observations did not detail, RS+ forecasters adjust their selections in the hazard matrix, resulting in greater clustering of their predictions, indicating reduced uncertainty. Due to uncertainty associated with avalanche forecasting, this framework for assessment should be used to track avalanche forecast efficacy and build a qualitative and quantitative historical record.Item Modeling snow water equivalent in complex mountainous terrain(Montana State University - Bozeman, College of Letters & Science, 2023) Beck, Madeline Makenzie; Chairperson, Graduate Committee: Eric A. Sproles; This is a manuscript style paper that includes co-authored chapters.The water stored in seasonal mountain snowpacks is a vital resource that approximately 20% of the world's population relies on for freshwater availability. However, accurately quantifying the amount of water stored in a snowpack, known as snow water equivalent (SWE), is difficult. The longest employed technique to quantify SWE is manual measurements. However, manual measurements of SWE are time intensive. As a result, researchers can collect relatively few point-based measurements across spatially extensive and complex regions. Automated weather stations may provide additional measurements of SWE and meteorological conditions but are expensive and difficult to maintain. Thus, reliable measurements of snow characteristics like SWE are scarce across time and space. A lack of extensive measurements causes data from few points to be extrapolated across spatially heterogeneous environments which increases uncertainty in estimates of water availability. Recent advances in satellite remote sensing allow researchers to observe snowpack dynamics across spatially continuous scales instead of relying solely on point-based measurements. However, current satellite technologies are incapable of collecting high- resolution snow data at the hillslope scale. Previous work has shown the importance of high elevation, hillslope-scale water storage reservoirs. Uncrewed aerial vehicles (UAVs) address the limitations of satellite remote sensing on the hillslope scale and are used to create high accuracy (<5 cm) models of snow depth. However, these models of snow depth provide no information on the amount of water stored without a value for snow bulk density. Thus, to capture hillslope dynamics of SWE, researchers must pair high-resolution models of snow depth with either directly measured or modeled bulk density of snow. This master's thesis integrates UAV-derived measurements of snow depth with modeled snow bulk density values to create continuous representations of hillslope-scale SWE across 9 flight dates. We found that each density modeling approach consistently underestimated SWE for the field site for each flight date except one. Further, each method of modeling snow bulk density was statistically indiscernible from each other. These findings highlight the heterogeneity of snow in mountainous terrain. In future work, bulk density models can be further parameterized to better represent site-specific values of SWE.Item Meteorological controls on wind slab properties(Montana State University - Bozeman, College of Letters & Science, 2023) de Leeuw, Nathalie Marika; Chairperson, Graduate Committee: Jordy HendrikxSnow avalanches are dangerous phenomena, which can be made increasingly consequential through wind transport of snow. Wind-deposited snow has a broad range of possible physical and mechanical properties which can vary greatly over short distances, creating inconsistent and thus difficult avalanche conditions. This variability causes particular challenges for avalanche workers in data-sparse regions where important snowpack information at desired scales may be unavailable. Instead, snowpack properties are commonly inferred from available meteorological data. Though wind slab properties vary in space and time as meteorological conditions change, previous work has not explicitly studied these relationships at the slope-scale. In this research I aim to better understand how changes in meteorological variables relate to changes in wind slab physical properties. During two winters I recorded temperature, humidity, and wind speed at study sites in Montana's Madison Range (45.237, -111.424) and collected snowpack data during or immediately following blowing snow events. I found that average wind speeds at 0.5m and 1.5m above the snow surface were significantly higher during hard wind slab formation than soft wind slab formation, while unobstructed wind speed, maximum gust, and the length of time of wind transport were not associated with wind slab hardness. Temperature was higher during hard than soft wind slab formation, while humidity was not different between the two hardness categories. Although wind speed at 1.5m had a significant positive linear relationship with both wind slab density and blade hardness gauge force, it was a poor predictor of actual values for both of these parameters. Our findings help improve the understanding of the impact of near surface winds on wind slabs, which will aid avalanche forecasting and mitigation planning particularly in windy climates.Item The hind limb ontogeny of Troodon formosus(Montana State University - Bozeman, College of Letters & Science, 2023) Boekenheide, Harris Russell; Chairperson, Graduate Committee: David J. Varricchio; This is a manuscript style paper that includes co-authored chapters.The Campanian theropod Troodon formosus has long been recognized as one of the most exceptional dinosaurs of the Late Cretaceous. Despite its relatively small size, it was a remarkably advanced and specialized creature, with one of the largest encephalization quotients among dinosaurs, serrated teeth with hypertrophied denticles, and long hind limbs suited for agility and energy-efficient locomotion. Yet much is still unknown about members of this species due to the fragmentary and disassociated nature of what has thus far been uncovered. In the hopes of better understanding this species, we used the histology and bone scaling of the pelvic limbs of Troodon and the modern emu to make inferences about its ontogeny. This resulted in the discovery of highly variable growth strategies in Troodon individuals, as well as further evidence that modern cursorial avians are not an apt modern analogue for Troodon ontogeny and locomotion.Item Structural analysis of the Gaurishankar Lineament to understand its role as a cross fault in the east-central Nepal Himalaya(Montana State University - Bozeman, College of Letters & Science, 2023) Baral, Nischal; Chairperson, Graduate Committee: Mary S. HubbardThe Gaurishankar Lineament (GL) in east-central Nepal is a topographic feature in eastern Nepal that has been proposed to be a cross-fault (faults perpendicular to the regional E-W strike). This feature has also been proposed to have blocked the lateral propagation of the thrust rupture that was activated during the Mw 7.8 Gorkha earthquake. To understand whether the GL is a cross fault, I conducted a field study along ~E-W traverses south of Gaurishankar peak in the Rolwaling (Greater Himalayan Sequence (GHS)) and in the central Tamakoshi and Jiri regions (Lesser Himalayan Sequence (LHS)). I augmented my fieldwork with petrographic and kinematic analysis of oriented samples. As circumstantial evidence for the GL representing the topographic expression of a cross fault, I identified multiple steep fracture patterns orthogonal to regional E-W striking fabric in the Rolwaling region and an additional system of NW striking fabric orthogonal to the NNE trending GL. In the Jiri region, the offset in a thin band of graphitic schist within the rocks of the LHS aligns along the GL and may represent part of a cross-fault system. An eastward plunging synclinal fold that covers the broad region between Tamakoshi and Jiri is disrupted to the east along the GL, also consistent with the presence of a cross fault. Several NW striking faults in the Jiri region end along the GL, as suggested by the topographic expression from the satellite imagery. Further study is needed to recognize and develop a comprehensive understanding of the GL as a cross fault and to explore a newly identified system of NW striking fault.Item Advancing airborne and spaceborne synthetic aperture radar measurements of ice and snow in the northern Great Plains(Montana State University - Bozeman, College of Letters & Science, 2023) Palomaki, Ross Theodore; Chairperson, Graduate Committee: Eric A. Sproles; This is a manuscript style paper that includes co-authored chapters.The cryosphere is responding to climate change in ways that have negatively impacted socio-environmental systems. Accurate and timely observations of the cryosphere are critical to adapting our infrastructure to these rapid changes. This dissertation contributes novel approaches to validating synthetic aperture radar (SAR) measurements over river ice and seasonal prairie snow. Previous C-band SAR-based river ice studies typically validate regional ice cover maps using aerial photos of frozen rivers. This qualitative approach relies on the principle that visually rougher ice should result in stronger SAR backscatter. In Chapter 2 of this dissertation I present the first systematic, quantitative investigation of the effect of river ice surface roughness on C-band Sentinel-1 backscatter. I employ Random Forest algorithms first to replicate qualitative classification results from previous studies, and then as regression models to explore relationships between Sentinel-1 backscatter and novel, quantitative surface roughness metrics derived from drone-based Structure-from-Motion datasets. Classification accuracies are similar to those reported in previous studies, but poor regression performance indicates a weak relationship between river ice roughness and Sentinel-1 backscatter. In Chapter 3, I extend these drone-based surface measurements of river ice with GPR-based subsurface measurements. Results from this smaller, richer dataset demonstrate that Sentinel-1 VV backscatter is correlated with ice thickness and VH backscatter with structural properties, but results are site-specific and more work is necessary to create generalized river ice models from Sentinel-1 measurements. Interferometric SAR techniques have been used to estimate snow water equivalent (SWE) using L-band measurements from the UAVSAR platform. These methods have been developed in mountainous areas and have not been investigated over prairie snowpacks, which typically feature exposed agricultural vegetation and greater spatial variability than found in mountain snowpacks. In Chapter 4 I develop a rigorous statistical framework to demonstrate that UAVSAR measurements over prairie snowpacks are sensitive to small changes in SWE, and are relatively unaffected by exposed agricultural vegetation. However, sub-pixel snow depth variability decreases the accuracy of SWE estimates derived from UAVSAR measurements. The upcoming NISAR satellite mission provides an opportunity to extend this work with repeated L-band measurements over a wider range of prairie snow conditions.