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Impacts of forest mortality on streamflow in whitebark pine forests within the greater Yellowstone ecosystem
(Montana State University - Bozeman, College of Letters & Science, 2024) Rautu, Teodora Stefana; Co-chairs, Graduate Committee: Brian V. Smithers and Danielle E. M. Ulrich
Increasing forest mortality across the western U.S. raises concerns about its impact on streamflow. The hydrologic role of whitebark pine (Pinus albicaulis Engelm.) is of particular interest given its ongoing decline and prevalence at the upper treeline where precipitation is highest. Understanding the link between disturbed whitebark pine forests and streamflow is essential for better informing water resource management. In Chapter One, I investigated streamflow changes in two Wyoming whitebark pine watersheds: Upper Wind River (53% area affected by beetle outbreak) and Buffalo Fork (53% area affected by beetle outbreak and fire). Streamflow significantly increased post-beetle for Upper Wind River but did not significantly change post-disturbance for Buffalo Fork, attributed to the fire's limited spatial extent and post- beetle effects potentially occurring in the pre-disturbance period. In Chapter Two, I integrated Leaf Area Index into a hydrologic model to reflect changing canopy conditions and assessed water balance variables that drove the observed changes in streamflow in Chapter One. I found that an increase in annual precipitation primarily led to the increase in observed streamflow more so than forest mortality, and snowpack and snowmelt were consistent predictors of streamflow metrics. My findings suggest monitoring snow dynamics for accurate real-time and future streamflow forecasting. In Chapter Three, I used streamflow field data and the same hydrologic model to assess the impact of increasing tree mortality on streamflow within a whitebark pine- dominated watershed in Big Sky, Montana. After simulating mortality levels ranging from 0-90% for one year, tree mortality did not substantially impact streamflow until the 90% mortality level where annual flow and late summer flow substantially increased. Considering that mortality levels between 25-50% are more representative of whitebark pine mortality in one year, the lack of substantial impacts on snowpack and streamflow at the 25-50% mortality levels challenges the traditional assumption that whitebark pine mortality would lead to reduced snowpack and reduced late summer flow in open watersheds with 30% forest cover. Future studies should assess the multi-decade impacts of whitebark pine mortality on hydrologic processes and consider species differences in evapotranspiration as other subalpine species replace whitebark pine.
Effectiveness of the nature-like fishway at Huntley Diversion Dam, Yellowstone River, Montana
(Montana State University - Bozeman, College of Letters & Science, 2022) Anderson, Ian Richard; Chairperson, Graduate Committee: Alexander V. Zale
We evaluated passage of a diverse fish assemblage through the nature-like fishway built around Huntley Diversion Dam, the uppermost of six low-head diversion dams on the Yellowstone River in Montana. Although nature-like fishways purportedly facilitate the passage of many species, relatively few have been evaluated, particularly on large rivers with unregulated discharge regimes. We examined seasonal and diel use of the Huntley fishway, quantified efficiencies and temporal metrics, and determined which factors influenced attraction and passage. We implanted > 3,500 fish of 14 species with passive integrated transponder tags, released most fish 250 m downstream of the fishway, and used stationary antennas to monitor movements of fish through the fishway in 2019 and 2020. Seasonal use of the fishway was generally associated with pre-spawning movements and occurred from April to August annually, and diel use reflected the known biology of each species. Attraction efficiencies were apparently low (usually < 50%), probably because of low motivation or the inability of fish to locate the entrance. Suckers released on opposite riverbanks downstream of the fishway were similarly successful at locating the entrance. Entrance efficiencies were usually > 90%. Both transit and passage efficiencies were usually > 60%, but fewer individuals (particularly among certain species) successfully passed than were able to transit to near the fishway exit. High river discharges were associated with decreased passage success and increased exit delays, probably because of problematic hydraulic conditions near the exit. Conditions throughout the rest of the fishway were appropriate, as most fish transited to near the exit in < 1 h regardless of discharge. Fourteen species passed upstream, demonstrating the functionality of nature-like fishways on large, unregulated rivers. However, the placement of such fishways must be thoughtfully considered to ensure that they remain effective over a wide range of environmental conditions.
Small scale denil development for use in headwater streams in southwest Montana
(Montana State University - Bozeman, College of Engineering, 2021) Conley, Megan Elizabeth; Chairperson, Graduate Committee: Kathryn Plymesser; Katey Plymesser, Kevin Kappenman, Matt Blank and Joel Cahoon were co-authors of the article, 'Arctic grayling (Thymallus arcticus) passage through a scaled denil fishway' submitted to the journal 'Journal of fish and wildlife management' which is contained within this thesis.
The Big Hole River is located in an agricultural valley in Southwest Montana and is home to the last fluvial (river dwelling) population of Arctic grayling (Thymallus arcticus) in the contiguous United States. Grayling mostly populate the tributary streams in the upper portion of the watershed, where there are many irrigation diversions, which greatly fragments grayling's natural habitat. While many of these irrigation diversions have fish ladders installed at them to assist with habitat reconnection, these ladder become impassable when the water levels get too low in the system or irrigators chose to block the fish ladders in order to divert more water. This study investigated and characterized a smaller scale Denil fish ladder that would use less water while providing adequate fish passage. Three different flow rate calculations were applied to a series of scaled Denils to compare to the expected flow rates of the full scale Denil to determine the scaled sizes to construct. A 0.6 scale and a 0.75 scale Denil were selected and hydraulic lab testing confirmed that 25.4 cm baffle spacing was the best for both scaled models. The fish swimming study, conducted at the outdoor flume at the Bozeman Fish Technology Center, used eight hatchery-raised grayling in each of the eight treatments. Each treatment was repeated 3 times using the 0.6-scale model for a total of 24 trials with 192 fish. Each treatment used a different combination of headwater depth (between 30.5 cm and 61.0 cm) and tailwater depth (between 15.2 cm and 61.0 cm). The grayling passed with near perfect success at all headwater and tailwater combinations except when the head difference between the headwater and tailwater was at its greatest (61.0 cm headwater and 15.2 cm tailwater). This preliminary study showed that grayling are willing to pass smaller-scale structures at a variety of flow rates but did not test a wide range of slopes, age classes or fish sizes. These results should be useful to water managers when looking to modify or install new Denil fishways in the Big Hole River Basin and around the western United States.
Towards a more-than-human geography of the Yellowstone River
(Montana State University - Bozeman, College of Letters & Science, 2020) Bergmann, Nicolas Timothy; Chairperson, Graduate Committee: Jamie McEvoy; Jamie McEvoy, Elizabeth A. Shanahan, Eric D. Raile, Anne Marie Reinhold, Geoffrey C. Poole and Clemente Izurieta were co-authors of the article, 'Thinking through levees: how political agency extends beyond the human mind' in the journal 'Annals of the American Association of Geographers' which is contained within this thesis.
This dissertation conceptualizes the Yellowstone River, flowing more than 670 miles from its headwaters in the mountains of northwestern Wyoming to its confluence with the Missouri River in western North Dakota, as a more-than-human assemblage. Specifically, this dissertation asks the following overarching research question: How does a more-than-human approach to understanding the Yellowstone River further geographical conceptualizations of human-environment relationships? In order to answer this question, this dissertation investigates the more-than-human aspects of both historical and contemporary environmental conflicts within Montana's portion of the Yellowstone River Basin. Chapter 2 examines the relationship between instream flow water law, Montana Fish and Game, and the Yellowstone River Basin. Drawing from both critical legal geography and political ecology, it furthers understandings of instream flow water law as relationally co-constituted through both human and nonhuman forces. Chapter 2 also traces the influence of Montana Fish and Game's more-than-anthropocentric ethical position on interpretations of the 1973 Montana Water Use Act. Chapter 3 uses a morethan- human approach to examine the relationship between myth and the Yellowstone River. Specifically, this chapter combines existing geographical understandings of myth with theories of assemblage and affect in order to historicize and denaturalize mythic belief in the Yellowstone as the longest undammed or free-flowing river remaining in the United States. Chapter 4 advances more-than-human understandings of political agency through a reframing of human thought as a co-constitutional assemblage of human and nonhuman elements. Relying on a comparative case study approach and qualitative interview data from two Montana communities located along the lower Yellowstone River, this chapter supports its theoretical claims through an embodied and affective analysis of the communities' divergent flood risk perceptions. Chapter 5 closes this dissertation with reflections on the value of using a more-than-human geographical approach.
Ecosystem engineering at the streambed: how net-spinning caddisflies influence substrate flow dynamics
(Montana State University - Bozeman, College of Letters & Science, 2020) MacDonald, Michael Joseph; Chairperson, Graduate Committee: Lindsey Albertson; Lindsey K. Albertson and Geoffrey C. Poole were co-authors of the article, 'Ecosystem engineering at the streambed: how net-spinning caddisflies influence substrate flow dynamics' submitted to the journal 'Ecohydrology' which is contained within this thesis.
The streambed is an ecotone between surface waters and underlying hyporheic systems. Identifying the controls on advective flow through this ecotone is critical to understanding the movement of energy and matter in streams. Hydropsychids (net-spinning caddisflies) are aquatic macroinvertebrate ecosystem engineers that influence streambed cohesion, yet evidence of direct influence on hydrologic processes is lacking. Utilizing a novel downward flow permeameter, we demonstrate how net-spinning caddisfly colonization of the streambed interstitia at moderate but common densities (2,000 m^-2) can reduce the vertical hydraulic conductivity (KV) by up to 55% in coarse sand and gravels (median diameter = 12.91 mm). Sediment columns incubated in artificial stream water occupied by caddisflies showed greater reductions in KV relative to those without caddisflies. Additionally, organic matter content within sediment columns showed that occupation by caddisflies resulted in nearly two-fold increases in organic matter AFDM. Our research shows that the ubiquitous and numerous net-spinning caddisflies are likely to modulate the exchange of channel and hyporheic water by constructing nets in open pore spaces, increasing flow resistance, and decreasing flow velocities, as well as stimulating organic matter deposition with potential consequences for biofilm growth. These results suggest that caddisfly induced reductions to flow may influence transfer processes occurring at the streambed ecotone, altering biogeochemical processes in streams.
Impacts of low summer streamflows on water resources in the Jefferson Valley : historical responses and future challenges
(Montana State University - Bozeman, College of Letters & Science, 2016) Leone, Alex Michael; Chairperson, Graduate Committee: Julia Hobson Haggerty
In an attempt to understand the complex interrelationships between climate, water infrastructure regimes, and water governance this thesis examines relationships between drought and water use in the Jefferson River Basin in southwest Montana. The Jefferson River is one of the three great headwater streams of the Missouri River and is itself comprised of the Beaverhead, Big Hole and Ruby Rivers, encompassing a substantial drainage basin of 9,532 sq. miles. The Jefferson's unique hydrological position inherently situates the basin "at the end of the line" of water users and flows at its confluence have plummeted to 200 cubic feet per second (cfs) during extreme drought periods, leaving little water in the river to appease appropriators along the river's remaining 80 miles. The Jefferson River (and all of its important tributaries) is highly utilized for agriculture, resulting in chronic dewatering during peak irrigation demand (typically July through mid-September). Persistent water scarcities over the last 15 years have tested the Basin's ability to sustain historic levels of agricultural production and maintain a commercial sports fishery. This thesis provides a resilience assessment of water resources in Jefferson Basin. RA's attempt to conceptualize dynamic interactions between linked social and ecological systems (SES's). Analysis of complex human use systems (SES's) is inherently interdisciplinary and necessitates a mixed methods approach. The RA completed for this thesis integrated physical analyses of the water use system (utilizing GIS, hydrology, climate and demographic data) with a qualitative survey of water stakeholders with the goal of understanding the processes that drive the Jefferson SES and identifying weaknesses that reduce resilience. Over the last 30 years the Jefferson Basin has benefited from a unique subset of water users and natural resource managers that have successfully worked to improve conditions in the face of extreme environmental challenges. This RA found that although it is highly likely that the Jefferson will be challenged by extreme conditions in the future (related to a changing climate), it is also evident that there is potential for the basin to transition into alternate and more resilient regimes.
The effect of watershed structure and climate on streamflow response, hydrologic memory, and runoff source areas
(Montana State University - Bozeman, College of Agriculture, 2014) Nippgen, Fabian; Chairperson, Graduate Committee: Jack Brookshire; Brian McGlynn, Lucy Marshall and Ryan Emanuel were co-authors of the article, 'Landscape structure and climate influences on hydrologic response' in the journal 'Water resources research' which is contained within this thesis.; Brian McGlynn, Ryan Emanuel and James Vose were co-authors of the article, 'Watershed memory at the Coweeta Hydrologic Laboratory: the effect of past precipitation and storage on hydrologic response' which is contained within this thesis.; Brian McGlynn and Ryan Emanuel were co-authors of the article, 'The temporal evolution of variable contributing areas' submitted to the journal 'Water resources research' which is contained within this thesis.
Watershed-scale hydrology research has long focused on understanding how various feedbacks in the soil-vegetation-atmosphere continuum affect streamflow. With this dissertation I sought to contribute to our understanding of how watershed characteristics (e.g. topography and vegetation) and climate affect various aspects of watershed hydrology, such as streamflow response times, watershed memory, and runoff source areas. Specifically, I was interested in 1) how watershed structure and climate affect inter- and intra-watershed variability in hydrologic response times, 2) how past precipitation and watershed memory affect runoff response on time scales of months to years, and 3) how runoff source areas vary through time. I approached these challenges/questions through a combination of spatially and temporally intensive and extensive observations synthesized as a) application of a simple lumped model to distill complex watershed behavior into comparable metrics across nested watersheds, b) empirical analysis of long-term hydroclimatic data sets to investigate the effect of watershed memory on the hydrologic response of watersheds, and c) the development of a parsimonious but fully distributed hydrologic rainfall-runoff model to characterize the effect of topographically driven lateral water redistribution and water uptake by vegetation on landscape scale hydrologic connectivity. We demonstrated that 1) differences in response times between watersheds were caused by differences in watershed structure while differences in response times between years were a function of maximum snow accumulation; 2) we found strong influences of past precipitation on runoff from monthly to annual time scales; 3) runoff source areas were highly variable over the course of two water years and exhibited hysteretic spatial behavior over the course of the snow melt seasons. This dissertation contributed new hydrologic understanding of how watershed properties (topography, geology, vegetation etc.), climatic variability, and the interactions between them affect hydrologic response at the watershed scale.
Transport of dissolved and particulate material in biofilm-lined tubes and channels
(Montana State University - Bozeman, College of Letters & Science, 2015) Jackson, Benjamin David; Chairperson, Graduate Committee: Tianyu Zhang; Isaac Klapper (co-chair)
This dissertation develops two models for biofilm-lined channels. The first model seeks to address the rate at which cells move in or out of the flow in a natural hot spring drainage channel. This is done by building a one- and then two-dimensional partial differential equation model of the stream. The model is parameterized using data gathered at Mushroom Spring in Yellowstone National Park in 2011 and 2012. Using this data, we predict erosion and adhesion rates at steady state in upper and lower regions of the stream. The second model describes the utilization of urea by biofilms in an artificial tube flow reactor. The goal of this model is to determine kinetic parameters for ureolytic biofilms. The model is created by deriving two coupled steady state ordinary differential equations, which are parametrized using experimental data. Once the model is fully described, an inverse problem is formulated and solved using a Markov Chain Monte Carlo method. From this model we obtain first order kinetic parameters for a particular strain of E. coli, and discuss results for Michaelis-Menten kinetics. These two model systems are linked by a set of intersecting elements. First, both models concern biofilm-lined channels. Second, in each model these biofilms are found in a streamflow system in which some component transfers from the flow to the biofilm or vice-versa. Third, both systems are represented by low dimensional mathematical models which seek to summarize complex physical behaviors using broad, summarizing parameters. Fourth, in both scenarios the parameters of interest are estimated by combining experimental measurements and mathematical modeling. Finally, error plays an important role in model efficacy. The effects of error are implicit in the first model, but explicitly analyzed in the second.
Life history characteristics and the effects of climate on growth of Yellowstone cutthroat trout in headwater basins
(Montana State University - Bozeman, College of Letters & Science, 2015) Uthe, Patrick Ryan; Chairperson, Graduate Committee: Alexander V. Zale; Robert Al-Chokhachy, Alexander Zale and Bradley Shepard were co-authors of the article, 'Life history characteristics and vital rates of Yellowstone cutthroat trout in two headwater basins' submitted to the journal 'Transactions of the American Fisheries Society' which is contained within this thesis.; Robert Al-Chokhachy, Bradley Shepard, Alexander Zale and Jeffrey L. Kershner were co-authors of the article, 'Effects of climate-driven stream factors on summer growth patterns of Yellowstone cutthroat trout' submitted to the journal 'Transactions of the American Fisheries Society' which is contained within this thesis.
The Yellowstone Cutthroat Trout was historically distributed throughout the Upper Yellowstone and Upper Snake River drainages, but now occupies only 42% of its original range because of habitat degradation and introduced salmonid species. Many of the current strongholds are located on public land in mountainous watersheds with low human disturbance. However, knowledge of life history characteristics of headwater populations is limited. Moreover, streams throughout the Rocky Mountains have already exhibited symptoms of climate change through alterations in thermal and hydrologic regimes, but it is unknown how these changes will affect fish populations. To address these needs, we implemented a mark-recapture study on five populations of trout from Spread Creek, Wyoming, and Shields River, Montana, to estimate annual growth, survival rates, and movement patterns, and document the effects of discharge, temperature, and food availability on summer growth patterns. Survival rates were high compared to survival rates of other Cutthroat Trout subspecies and large trout generally had lower survival rates than small trout. Downstream movements out of streams by tagged trout were substantial. Annual growth rates varied among streams and size classes, but were relatively low compared to populations of Yellowstone Cutthroat Trout from large, low elevation streams. Trout grew more in length than weight in summer, suggesting an investment in structural growth rather than accumulation of reserve tissues. Temperature and discharge had strong effects on summer growth, but the effect of discharge was greater for growth in weight than in length, probably resulting from increased prey availability at high discharges. Temperature interacted with fish length such that small trout responded favorably to increased average daily temperatures near physiological optima and increased growing season length, whereas large trout responded negatively to warming temperatures. These estimates of key demographic parameters are useful in developing management and conservation strategies. Additionally, we documented that even under thermally suitable conditions, discharge can have significant effects on growth, making it important to consider multiple factors affected by climate change when devising climate adaptation strategies for coldwater fishes.
Distribution, relative abundance, and habitat associations of Milk River fishes related to irrigation diversion dams
(Montana State University - Bozeman, College of Letters & Science, 2001) Stash, Sean William

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