Theses and Dissertations at Montana State University (MSU)

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    Exploring variation in diversity of arthropod communities in grasslands of Yellowstone National Park
    (Montana State University - Bozeman, College of Letters & Science, 2024) Segal, Carlisle Regina; Chairperson, Graduate Committee: Andrea Litt; This is a manuscript style paper that includes co-authored chapters.
    Community ecologists have proposed many hypotheses to explain the mechanisms that drive patterns of diversity in plants and animals. For arthropods, understanding community assembly may have important conservation implications, given that this group provides many vital ecosystem services, yet many arthropods are in decline globally. We investigated drivers of arthropod diversity by testing the habitat complexity hypothesis, productivity hypothesis, and intermediate disturbance hypothesis in grasslands in the northern range of Yellowstone National Park. We collected data on vegetation (vegetation cover, litter cover, vegetation height, remotely sensed biomass, and the normalized difference vegetation index) and bison movement as explanatory variables, and sampled arthropods to help us test our hypotheses. We used generalized linear models and multivariate methods to explore patterns of richness and composition of arthropod communities among our sites. We found limited evidence for the habitat complexity hypothesis; richness of predators increased with heterogeneity in litter cover. In contrast, richness of multiple functional groups decreased with heterogeneity in vegetation cover and we did not detect any relationships with heterogeneity in vegetation height. We found evidence supporting the productivity hypothesis among herbivores; richness of herbivores overall and chewing herbivores were positively related to net primary productivity, whereas richness of omnivorous arthropods decreased with increased biomass. Although the intermediate disturbance hypothesis predicts that species richness will be maximized at moderate levels of disturbance, we found the lowest richness of all arthropods and that of multiple functional groups at moderate levels of disturbance. Overall, we found that herbivorous arthropods were more affected by quality and quantity of vegetation, whereas upper-trophic feeders were more affected by habitat complexity. These findings highlight that different functional groups of arthropods are driven by different mechanisms. By considering diversity metrics beyond taxonomic classification, we can gain important insights about arthropods - a diverse, understudied taxa.
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    Dam removals: an agricultural analysis
    (Montana State University - Bozeman, College of Agriculture, 2024) Bush, Nathan Alexander; Chairperson, Graduate Committee: Melissa C. LoPalo
    Dam removals are occurring with increased frequency throughout the United States. 77% of all dam removal projects in U.S. history have occurred in the 21st century and the number of dams being removed each year is rising. Dams often play a key role in agricultural production, making it important for agricultural producers and policymakers to understand the effects of these removals as they become more common. This paper explores the causal effects of dam removal on agricultural productivity in the United States using a two-way fixed effects event study and an instrumental variable framework. Primary results of the analysis are mixed and differ based on exact specifications used but show initial evidence of per acre crop productivity increases and cash receipt declines following a removal. Further research is needed to explore the fine-scale effects of dam removals on individual agricultural producers and to expand on the preliminary causal relationships observed in this paper.
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    In-nii (Bison bison L.) reintroduction to Amskapiipikini (Blackfeet) Nation homeland: relationships with ksahko (soils)
    (Montana State University - Bozeman, College of Agriculture, 2022) Tatsey, Latrice Dawn; Chairperson, Graduate Committee: Anthony Hartshorn
    In-nii (American Bison) are returning to their Traditional Territories after being nearly wiped out of the Great Plains of North America and Canada. The in-nii are slowly returning to Native American tribes who have the resources to run reintroduction programs like that of the Amskapiipikini (Blackfeet). This in-nii reintroduction presented an opportunity to look at the effects of the return of in-nii to the Amskapiipikini, and what their influences might be on the soils, plants, and water resources of the Blackfeet Nation. This research project was conducted on the Blackfeet Buffalo (In-nii) Ranch and the adjacent RRJ Cattle Ranch, comparing the influence of in-nii and cattle on soil nutrient cycles and soil carbon dynamics. Soil samples were taken from locations on the landscape that were near water sources on lower elevations, mid hillslopes for mid-elevation sites and on hilltops at higher elevations. Soil characteristics included soil organic matter (SOM), nitrate, pH, cation exchange capacity (CEC), and exchangeable calcium, potassium, sodium, and magnesium. Only two (CEC, magnesium) appeared to have been influenced by in-nii and cattle. The remaining soil characteristics were little influenced by grazer type. Substrate-induced respiration was also measured in the lab to see how microbes decomposed SOM (carbohydrates and other molecules) to release energy and CO2; we found no evidence of differences between in-nii- and cattle-influenced soils. Finally, we measured field respiration rates and water infiltration rates at multiple fence line sites; field soil respiration rates increased when soil had water infiltrated after the dry readings, soils also increased the time to absorb water after the first infiltration tests were run. Our preliminary results suggest that the reintroduction of in-nii to these lands has not yet resulted in measurable differences in soil-related properties of the Blackfeet Nation. Even so, the return of the in-nii for the Amskapiipikini is also about understanding the importance of using cultural science when studying the ecology of a system. Doing this can create an understanding of the traditional ways of knowing while bringing cultural healing and restoring connections between Amskapiipikini, in-nii, and land.
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    Aquatic invertebrate colonization as a river restoration success criterion: a case study of the upper Blackfoot mining complex superfund site
    (Montana State University - Bozeman, College of Agriculture, 2023) Deyoe, Matthew Len; Co-chairs, Graduate Committee: Anthony Hartshorn and William Kleindl
    In 1975 the Mike Horse Dam partially collapsed, releasing 200,000 tons of cadmium, copper, iron, lead, manganese, and zinc into the streams and floodplains on the Upper Blackfoot Mining Complex (UBMC) in Montana, USA. The magnitude of the material that was toxic to humans from this event triggered the federal Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), which currently governs 1,329 sites across the USA. Portions of the $39 million lawsuit in 2008 with the American Smelting and Refining Company (ASARCO), funded the remediation and restoration of 37 hectares of floodplains, wetlands, and stream channels. Although CERCLA's success criteria focus on reducing risk to human health from hazardous substances, the Montana Natural Resource Damage Program was interested in aquatic invertebrate colonization of the restored river ecosystems, since they are monitoring progress of restoration. To answer this, I explored whether observations of invertebrate colonization could gauge restoration success and identify aquatic invertebrate-based tools for future restoration projects. Over three years, I compared invertebrate communities at five impacted "restored" sites on the UBMC with ten unimpacted "reference" sites. I then quantified colonization using seven indices: four statistical taxonomic diversity and similarity indices, the River Invertebrate Prediction and Classification System (RIVPACS), the Benthic Index of Biotic Integrity (B-IBI), and a new Stable Isotopic Colonization Index (SICI) which estimated isotopic complexity using metrics derived from delta 15N and delta 13C stable isotopes. Statistical diversity and similarity indices showed the restored sites were diversifying quickly. For example, from 2020 to 2023, the average (+ or - 1SD) Shannon Diversity of restored sites increased from 1.1 + or - 0.5 to 1.8 + or - 0.43 while reference was 2.1 + or - 0.3. The average B-IBI of restored sites increased from 11.1 + or - 4.8 in 2020 to 31.7 + or - 7.7 in 2023 while reference B-IBI was 65.7 + or - 4.5, indicating ongoing ecosystem recovery, but this index required taxonomic identification to the genus level. The average SICI for restored sites was 23.3 + or - 6.1 and reference was 54 + or - 9.2, and SICI required identification to the family level. Restoration efforts on the UBMC have resulted in a promising trajectory, but continuous monitoring is imperative to ascertain if restored streams have reached reference conditions.
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    Environmental drivers of bee community diversity in Yellowstone National Park
    (Montana State University - Bozeman, College of Letters & Science, 2022) Switzer, Kristen Ann; Chairperson, Graduate Committee: Laura Burkle
    Pollinators are essential to their ecosystems and facing large declines. Studies on environmental drivers of bee community composition are currently lacking in North America, particularly in national parks. Understanding how bee diversity and plant-bee interactions change across environmental gradients gives us insight into the resilience of bee communities in the future. We collected data at seven sites across an elevational gradient in Yellowstone National Park. Pan traps were used to collect bee diversity data from in 2010, 2011, 2012, and 2020, and hand-netting was used to collect plant-bee interaction data from June to August 2020. We hypothesized that elevation would be a major driver of bee abundance, species richness, and community composition and that bee diversity would decrease as elevation increased. We predicted bee diversity would peak in the middle of the growing season in response to floral diversity peaking at that time. Finally, we predicted plant-bee interactions would be more generalized at higher elevations and flower species richness would be a major driver of network specialization (H2'). Our results revealed that seasonality and elevation were major drivers of bee abundance and species richness, indicating that both spatial and temporal factors are important in driving bee community patterns. Bee species richness was highest in 2010 and declined over years, which may signal that changing environmental conditions are stressing bee communities. Bee abundance and species richness declined as each growing season progressed, which aligns with broader literature on various taxa and mirrors seasonal flower diversity patterns. Despite close alignment between bee and floral diversity patterns, flower species richness was only a significant driver of bee community composition, indicating that other environmental gradients were bigger drivers of bee abundance and species richness patterns. Bee species richness was a significant driver of plant-bee network specialization and elevation, slope, and flower species richness were marginally significant, suggesting that plant- bee interactions are influenced more by spatial than temporal variables. Additional studies focusing on bee diversity across growing seasons and years could provide insights into how changing environmental conditions in the future may influence bee diversity and community resilience in Yellowstone National Park.
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    Reproductive ecology of hatchery-origin pallid sturgeon upstream of Fort Peck Reservoir, Montana
    (Montana State University - Bozeman, College of Letters & Science, 2020) Cox, Tanner Lewis; Chairperson, Graduate Committee: Christopher S. Guy; Christopher S. Guy and Molly A. H. Webb were co-authors of the article, 'First maturity, spawning periodicity, and follicular atresia of hatchery-origin pallid sturgeon in the Missouri River above Fort Peck Reservoir, Montana' submitted to the journal 'Journal of applied ichthyology' which is contained within this thesis.; Christopher S. Guy and Molly A. H. Webb were co-authors of the article, 'Reproductive ecology and behavior of hatchery-origin pallid sturgeon in the Missouri River above Fort Peck Reservoir, Montana' submitted to the journal 'Journal of applied ichthyology' which is contained within this thesis.
    Conservation propagation of pallid sturgeon above Fort Peck Reservoir has successfully recruited a new generation of spawning-capable pallid sturgeon to a location that would otherwise have fewer than 30 remaining. Successful recovery of pallid sturgeon will now rely on spawning in locations that provide adequate drift distance for larvae to recruit. Prior to this study, all reproductively-active female pallid sturgeon underwent ovarian follicular atresia. The reasons for and prevalence of ovarian follicular atresia were unclear, spawning periodicity of females remained undescribed, and remaining prepubescent fish indicated that age- and size-at-first maturity would vary more than currently described. Furthermore, spawning location, spawning-related interactions among conspecifics, and substrate composition at spawning locations remained undescribed. We used data on reproductive status and location to describe age- and size-at-first maturity, the prevalence of ovarian follicular atresia during first gametogenic cycles, spawning periodicity for female and male pallid sturgeon, where spawning occurs, if spawning locations are related to discharge, if substrate characteristics at the spawning locations were similar to other river reaches, and if female, male, and atretic female pallid sturgeon use the river similarly. Pallid sturgeon matured at older ages and larger sizes than described for other populations with females maturing at 18 years old and males at 15; however, prepubescent pallid sturgeon as old as 20 were documented. During the presumed-first gametogenic cycle, 62.5% of female pallid sturgeon underwent follicular atresia. Females had biennial reproductive cycles, and males had annual and biennial reproductive cycles. Reproductively-active male and female pallid sturgeon were found in similar locations, while locations of atretic female pallid sturgeon varied. The furthest upstream locations of pallid sturgeon including locations in the Marias River occurred during 2018 when discharge was at an unprecedented high. Spawning occurred in locations less than 131 km from the river-reservoir transition zone, which does not provide adequate drift-distance for larvae. Altering discharge and water temperature at Tiber Dam to mimic observed values in 2018 may increase use of the Marias River by pallid sturgeon during spawning, which would provide adequate drift distance to larvae.
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    Geographies of mobility and belonging: critical plant studies and hopeful worldviews
    (Montana State University - Bozeman, College of Arts & Architecture, 2020) Rasile, Alayna May; Chairperson, Graduate Committee: Josh DeWeese
    This paper makes a case for the miraculous nature of vegetal life and subverts the cultural failings of western civilization that have omitted ecological literacy and replaced it with ecosystem manipulation. Through examining the resiliency, adaptability, and mobility of plants, this thesis proposes a reconsideration of the idea of vegetal life being 'rooted' or immobile by choosing a posthuman lens that challenges the linear, human-scaled time and the Cartesian split of mind and body. Through my research on textile technology and my conviction for mutualistic co-species relationships, I explore opportunities for humans to use the implicit structure of capitalism with a methodology that is regenerative for landscapes and supportive of diverse vegetal life. These market-based solutions allow for positive material relationships with all aspects of an ecosystem.
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    Approaching the science of food waste through documentary film
    (Montana State University - Bozeman, College of Arts & Architecture, 2019) Bates, Samantha Ellyn; Chairperson, Graduate Committee: Lucia Ricciardelli
    'Trash' does not exist in nature, as any waste generated by an organism is utilized by another. Humans have strayed away from the earth's natural processes by exporting waste towards a dead end, allowing it to pile high in landfills where it most likely will never decompose. Documentary filmmakers have attempted to raise awareness about this pressing environmental issue of waste by illustrating the negative impacts of landfills on our lives and providing the viewer with attainable and sustainable waste diversion solutions. This study will describe, discuss, and compare the different aesthetic and thematic approaches adopted in 'Wasted!' 'The Story of Food Waste', 'Just Eat It: A Food Waste Story' and 'Rot', three documentary films that propose environmentally-friendly waste disposal strategies as possible solutions to our global food waste crisis.
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    Vehicles, grooming, and other factors affecting snowroad longevity in Yellowstone National Park
    (Montana State University - Bozeman, College of Engineering, 2018) Nelson, Molly McKellar; Chairperson, Graduate Committee: Edward E. Adams
    In winter, the National Park Service (NPS) at Yellowstone grooms snow that builds up on the park roads, making 'snowroads' passable by snowmobiles and snowcoaches. The NPS has recently allowed experimental snowcoaches on low-pressure tires (LPTs) in addition to traditional tracks. As they consider a permanent policy on these LPTS, they want to understand these vehicles' impacts on snowroads compared with those of traditional tracked vehicles and snowmobiles. They also want to know how to optimize other operations (e.g., grooming) to maintain quality roads that support safe travel through the park. This two-year field study investigated the snowroad quality in the park and factors influencing this quality. The approach involved data collection on both parkwide road conditions and individual vehicle passes. Both controllable and non-controllable factors were considered to provide information on their relative influence. Parkwide road quality analysis involved collecting GPS data on grooming activity, weather data from existing stations, road depth through radar measurements, traffic counts from motion-sensor cameras, hardness data, and snow sample analysis. The vehicle-by-vehicle impact study involved both subsurface and surface measurements in the road. Load cells, accelerometers, a high-speed, high-definition camera, a penetrometer, and a 'profilometer' provided measurements. Data analysis combined with existing literature provided insights into best practices for the NPS. Parkwide, snowroads harden throughout the season, with temperatures and traffic load being contributing factors. Grooming results in a harder road if snow disaggregation is followed by compaction, and with a longer set time between grooming and traffic. Individual vehicles' impacts are driven by surface interaction rather than motion at depth in the snowroad. On hard, groomed snowroads, both tracked and LPT snowcoaches can form ruts, but tracked vehicles continue to dig ruts deeper whereas LPT coaches' ruts level out and stop deepening with subsequent passes. This seems to be because LPTs form ruts primarily through compaction and tracked vehicles through snow displacement. Reduced tire pressures reduce rut formation and can harden the road. Results from this study demonstrate that LPT coaches should not be disallowed from Yellowstone based on road impacts. Other results will inform NPS operations to optimize grooming practices.
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    A Yellowstone snowroad rutting investigation: a comparison of tracks vs. tires and other contributing factors
    (Montana State University - Bozeman, College of Engineering, 2018) Phipps, Ry Edward; Chairperson, Graduate Committee: Daniel Miller
    Yellowstone National Park (YNP) has been experiencing more snowroad rutting in the last ten years. Additionally, YNP has recently (winter 2013 -2014) been experimenting with permitting large low-pressure tire vehicles to operate on the parks' snowroads. To gain a better understanding of snowroad degradation, YNP employed a team of snow scientists from Montana State University. In the winter of 2015, a large scale, two year, snowroad rutting study began in YNP. Parameters pertaining to snowroad strength and the difference in impact to the snowroads between tracked and wheeled vehicles were examined. This thesis in addition to Nelson's (2018) thesis produce a detailed overview of controllable and uncontrollable factors of maintaining and measuring impacts to the snowroads of Yellowstone National Park. Instruments were developed to collect data in the field and in the Sub-Zero Lab at Montana State University. These instruments allowed researchers to quantify crucial differences between vehicle types and the behaviors associated with them. Once data was collected, the data was post-processed in various ways to analyze trends pertaining to snowroad strength and degradation. With the data processed and analyzed, the profilometer and hardness data proved to be the most informative on snowroad degradation tendencies, however, the other instruments helped reinforce conclusions made with the hardness and profilometer data. The process of taking subsurface measurements on vehicle pass-bys, allowed researchers to confirm that rutting is most closely tied to vehicle-surface interactions (~ top 10 cms). It was determined that wheeled and tracked coaches can both cause ruts but by different processes. Wheeled vehicles are primarily causing ruts through compaction whereas tracked vehicles primarily cause ruts through a process of snow displacement. Ruts form from wheeled coaches but after subsequent passes the cross-sectional area of the rut tends to level off, especially when inflation pressure is decreased. While tracked vehicles' ruts continue to grow in size after subsequent passes. Additionally, snowroad hardness was affected differently between tracks and tires. Tracks and tires at higher pressures (> or = 62 kPa) tended to more often soften the snowroad, whereas lower pressure tires (< 62 kPa) tended to harden the snowroad.
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