Theses and Dissertations at Montana State University (MSU)
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Item Spectral processing for algae monitoring and mapping (SPAMM): remote sensing methodologies for river ecology(Montana State University - Bozeman, College of Engineering, 2024) Logan, Riley Donovan; Chairperson, Graduate Committee: Joseph A. Shaw; This is a manuscript style paper that includes co-authored chapters.Inland water quality is a growing concern to public health, riparian ecosystems, and recreational uses of our waterways. Many modern water quality programs include measures of the presence and abundance of harmful and nuisance algae. In southwestern Montana, large blooms of the nuisance algae, Cladophora glomerata, have become common in the Upper Clark Fork River due to a combination of warming water temperatures, naturally high phosphorus levels, and an influx of contaminants through wastewater and anthropogenic activity along its banks. To improve understanding of bloom dynamics, such as algal biomass and percent algae cover, and their effects on water quality, a UAV-based hyperspectral imaging system was used to monitor several locations along the Upper Clark Fork River. Image data were collected across the spectral range of 400 - 1000 nm with 2.1 nm spectral resolution during field sampling campaigns across the entirety of the project, beginning in 2019 and ending in 2023. In this dissertation, methodologies for monitoring water quality were developed. These methods include estimating benthic algal pigment abundance using spectral band ratios achieving R 2 values of up to 0.62 for chlorophyll alpha and 0.96 for phycocyanin; creating spatial algae distribution maps and estimating percent algae cover using machine learning classification algorithms with accuracies greater than 99%; combining spatial algae distribution maps and improved pigment estimation using machine learning regression algorithms for creating chlorophyll alpha abundance maps, achieving an R 2 of 0.873, while also comparing abundance values to Montana water quality thresholds; and identifying salient wavelengths for monitoring and mapping algae to inform the design of a low-cost and compact multispectral imager. Throughout all field campaigns, significant spatial variations in algal growth within each river reach and frequent violations of current water quality standards were observed, demonstrating the need for high-spatial resolution monitoring techniques to be incorporated in current water quality monitoring programs.Item Stream ecology as place-based education(Montana State University - Bozeman, College of Letters & Science, 2023) Schlobohm, Jennifer; Chairperson, Graduate Committee: C. John GravesMuch of modern-day education is not related the lives of students. Place-based education has been noted to increase academic performance, and students' connection to the place they live. This study used the local stream to investigate the impact of place-based education in an Earth and Space science class. Student summative assessment scores and Likert-style surveys were used in both treatment and non-treatment units to analyze academic growth, sense of place, and self-efficacy regarding scientific skills. A questionnaire was given at the end of the treatment unit and used to collect qualitative data to support the conclusions. Normalized gains and percentages of summative assessment scores identified student growth in all areas studied.Item Macroinvertebrate diversity, community structure, and dispersal are affected by tributary identity and confluence conditions in a regulated river(Montana State University - Bozeman, College of Letters & Science, 2023) Maguire, Zachary John; Chairperson, Graduate Committee: Lindsey Albertson; This is a manuscript style paper that includes co-authored chapters.Tributaries are essential components of freshwater ecosystems, playing a crucial role in maintaining connectivity and providing habitat for a diverse array of aquatic organisms. The role of tributaries in creating heterogeneity in physical conditions and food resources for fishes could be critical, yet little is known about how variable conditions in different tributaries in regulated river systems influence the mainstem. Using field observations in five tributaries on the Madison River, Montana, we found that tributaries in the same network and within relatively short distances of 60km varied greatly in their environmental conditions, macroinvertebrate densities, and macroinvertebrate community structure. Downstream of confluences macroinvertebrate richness increased overall, and per capita weight of drifting macroinvertebrates decreased overall. These findings suggest that confluences may act as hotspots for biodiversity in regulated rivers and introduce smaller bodied macroinvertebrates to the drift. The amount that a tributary influenced benthic richness and mean per capita weight in the drift downstream of its confluence was related to land use and abiotic factors within that tributary; both macroinvertebrate metrics significantly increased in magnitude downstream of confluences with higher percentage of US Forest Service land, cooler temperatures, decreased discharge, and increased elevation loss (i.e. steeper watershed slope). In contrast, tributaries that had a larger proportion of agricultural land, warmer temperatures, and higher discharge more strongly influenced benthic macroinvertebrate metrics. These tributaries supported higher benthic density and biomass downstream of confluences. Our results offer insight into the ways that tributaries can create heterogeneous habitats that in turn structure macroinvertebrate communities in mainstem rivers and suggest that conservation and restoration of these essential components of freshwater ecosystems is a well-spent endeavor in rivers with regulated mainstems. Future research will need to test the ubiquity of the patterns we observed in other river networks and under other global changes such as pollution, invasive species, and drought. Continued understanding of the importance of heterogeneity imparted by tributaries and their confluences on diversity, availability, and quality of food for threaten fishes is needed to guide restoration efforts aimed at improving river condition and resilience.Item Daily signals in nitrate processing provide a holistic perspective on stream corridor hydrologic and biogeochemical function(Montana State University - Bozeman, College of Agriculture, 2023) Foster, Madison Jo; Chairperson, Graduate Committee: Robert A. Payn; This is a manuscript style paper that includes co-authored chapters.Understanding interactive pathways of biogeochemical reaction and water movement in stream corridors is critical given the role stream corridors play in mitigating nitrate loading from agricultural watersheds. However, few studies consider the interactive effects of nitrate loading, riparian processing, and stream ecosystem processing, which may limit abilities to predict downstream nitrate delivery. Riparian groundwater inputs and stream ecosystem processing may vary due to daily cycles in evapotranspiration or stream ecosystem primary production. Recent advances in high-frequency monitoring of stream chemistry throughout the day exhibit potential to explore both hydrologic and biogeochemical influences on nitrate attenuation. In this thesis, I explore how diel variations in stream reach nitrate processing can provide holistic perspectives on the attenuation of nitrate along stream corridors within a watershed that is heavily influenced by agricultural land use. Nitrate processing is defined as the evident changes in nitrate concentration in parcels of water as they travel along a given reach of a stream, as measured from nitrate sensors located at the head and base of ca. 0.5 km reaches. To understand controls on diel variation in nitrate processing, we measured diel processing signals in agricultural headwater reaches in Central Montana, USA spanning variable atmospheric and flow conditions from March through August in 2020-2022. Across 168 days with valid data, most signals exhibited little diel variation (n = 106) and this lack of variation occurred most frequently during cooler and shorter days. In contrast, signals with greater variation were common during longer days, warmer temperatures, and lower flows (n = 62). This seasonal shift in patterns suggests that solar radiation and stream flow are primary controls on diel nitrate processing signals in these low-order reaches. In addition to diel variation, less overall nitrate attenuation in the study reach with direct inputs of high-nitrate upland waters suggest that the degree of hydrologic connection to upland aquifers influences apparent reach nitrate processing. This work highlights how understanding the drivers of diel processing signals may lead to a more holistic understanding of how multiple interacting processes in stream corridors influence nitrate delivery to downstream ecosystems.Item Positive effects of ecosystem engineers on stream communities and processes(Montana State University - Bozeman, College of Letters & Science, 2022) Tumolo, Benjamin Bartley; Chairperson, Graduate Committee: Lindsey Albertson; This is a manuscript style paper that includes co-authored chapters.Ecosystem engineering is a process by which organisms modify habitat characteristics and influence community structure and ecosystem function. These engineer-mediated habitat modifications often have positive effects on community members by improving or creating novel habitats that ameliorate harsh conditions. Despite the far-reaching consequences of such positive interactions, most of what we know about ecosystem engineering is limited to marine or terrestrial habitats and focused on sessile, long-lived foundation species. Less recognition has been given to mobile, smaller bodied, and shorter-lived insect engineers within freshwater ecosystems. This knowledge gap is significant as freshwaters are one of the most threatened habitats globally, and freshwater insects are experiencing alarming rates of decline. My dissertation seeks to uncover how organism interactions modify physical and resource environments in ways that can affect community structure and ecosystem function. My objectives were to: 1) synthesize literature to develop a conceptual framework aimed at describing how two distinct mechanisms of positive interactions scale over time and space; 2) measure how net-spinning caddisfly (Hydropsychidae) engineers and their abandoned engineering structures differentially facilitate communities; 3) quantify the importance of beneficiary functional traits and environmental gradients in determining the strength of facilitation between caddisflies and invertebrate communities; and (4) test how caddisflies can generate hotspots of community assembly and ecosystem function. I found that caddisfly ecosystem engineers and their abandoned structures increased invertebrate colonization; however, occupied structures supported greater colonization of Chironomidae compared to abandoned structures. Additionally, I found that the strength of caddisfly facilitation increased with increasing elevation and was dependent on small-bodied beneficiaries. Furthermore, I found that caddisfly engineers generated ecological heterogeneity by aggregating both resources and consumers, with consequences for elemental cycling. Overall, my dissertation emphasizes the role that biology can play in modifying environments and how these alterations can positively influence biological communities with consequences for ecosystem function.Item Understanding hydrogeomorphic influences on stream network denitrification and temperature dynamics(Montana State University - Bozeman, College of Agriculture, 2020) Carlson, Samuel Paul; Chairperson, Graduate Committee: Geoffrey PooleThe removal of nitrate from stream networks through the process of denitrification is an important component of local and regional nutrient cycles, but the controls on stream network denitrification rates remain poorly understood. Previous work has demonstrated general effects of stream channel size and nitrate loading rates on network-scale denitrification rates, but has been unable to elucidate connections between the complex environmental template of streams, and resulting denitrification rates. Understanding links between land use and management practices, physical characteristics of streams, and stream denitrification rates is critical to interpreting observed patterns of nitrate in freshwater systems and forming holistic management strategies for reducing the negative effects of elevated nitrate concentrations. To address these critical uncertainties, I developed a stream network simulation model that incorporates the effects of whole-stream aerobic respiration on biotic denitrification demand. This model is applied to a small, subalpine stream network under scenarios designed to explore: 1) the implications of temperature-controlled, network scale patterns of respiration rates on the distribution and overall magnitude of stream network denitrification, and 2) the effect of logging-induced channel simplification on whole network denitrification rates. The first analysis is complimented by an evaluation of controls on stream temperature across this network, revealing the spatially and temporally variable influence of in-network lakes on stream temperatures. Results from the first analysis suggest that reach- and network-scale denitrification rates are strongly influenced by respiration rate and temperature when nitrate supplies are high relative to removal rates, indicating an increased contribution of lower, warmer streams to whole-network denitrification. The second analysis reveals that historical logging has caused a ~30% loss of stream network denitrification capacity, which is manifested as a corresponding reduction in whole-network denitrification rates when nitrate supplies are not limiting. In sum, this work emphasizes the diverse set of factors that influence reach- and watershed-scale biogeochemical characteristics and processes, and suggests that land management actions which influence stream morphology may also alter stream denitrification rates.Item 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.Item Influence of thermal regime on the life histories and production of Rocky Mountain aquatic insects(Montana State University - Bozeman, College of Letters & Science, 2019) McCarty, Jennifer Denise; Chairperson, Graduate Committee: Wyatt F. CrossLife history traits of aquatic insect taxa such as metabolism, terminal body size, and fecundity vary along natural thermal gradients. Body size, in particular, is expected to respond to temperature and may have important consequences for fecundity and the production of insects. The Thermal Equilibrium Hypothesis (TEH) predicts that aquatic insect taxa are most abundant at an intermediate 'optimal' temperature where life history traits such as terminal body size and reproductive potential are maximized, i.e., the thermal 'optimum'. A competing hypothesis, the Temperature Size Rule (TSR), predicts that individuals developing at the coldest temperatures in their range will grow more slowly, but attain the largest body sizes and therefore exhibit greater fecundity than individuals growing at warmer temperatures. Implicit in both of these theories is that population-level production, a measure of population 'success', will be greatest where terminal body size and fecundity are maximized. Few studies have investigated the TEH in the field, and none have measured the relationship between production and other life history traits in the context of these theories. Our study focused on three common Rocky Mountain aquatic insect taxa: Drunella doddsii, Hydropsyche cockerelli, and Ephemeralla infrequens. We quantified the influence of thermal regime on growth rates, terminal body size, reproductive potential, and population-level biomass and production, all of which potentially limit the longitudinal distribution and success of these taxa. We found that growth varied strongly with season and site, leading to significant variation in the timing of growth and terminal body size. Reproductive potential was negatively associated with mean annual temperature as predicted by the TSR. Unexpectedly, reproductive potential was not always correlated with terminal body size. Population density, biomass, and secondary production were generally positively correlated with terminal body size for D. doddsii and H. cockerelli, as expected from both predictive models. In contrast, these relationships were not as consistent for E. infrequens. Our findings provide new insight as to how thermal variation influences the ecology of aquatic insects in the context of the TEH and TSR. Our results should be valuable for predicting population and community responses to ongoing changes in climate.Item The effects of temperature on stream ecosystem structure, secondary production, and food web dynamics(Montana State University - Bozeman, College of Letters & Science, 2019) Junker, James Robert; Chairperson, Graduate Committee: Wyatt F. Cross; Wyatt F. Cross, Jonathan P. Benstead, Alexander D. Huryn, James M. Hood, Daniel Nelson, Gísli M. Gíslason and Jón Ólafsson were co-authors of the article, 'Patterns and drivers of ecosystem-level biomass and stoichiometry in streams' submitted to the journal 'Ecosystems' which is contained within this thesis.; Wyatt F. Cross, Jonathan P. Benstead, Alexander D. Huryn, James M. Hood, Daniel Nelson, Gísli M. Gíslason and Jón Ólafsson were co-authors of the article, 'Resources govern the temperature-dependence of animal production at multiple timescales' submitted to the journal 'Ecology letters' which is contained within this thesis.; Wyatt F. Cross, Jonathan P. Benstead, Alexander D. Huryn, James M. Hood, Daniel Nelson, Gísli M. Gíslason and Jón Ólafsson were co-authors of the article, 'Responses of food web organic matter fluxes to temperature and their implications for food web stability' which is contained within this thesis.Since 1880, Earth's mean temperature has risen ~0.85 °C, and increases >1.5 °C are likely by the end of the 21st century. Warming temperatures will continue to shuffle and restructure ecological communities and the consequences of these changes for ecosystem processes and services are largely unknown because of the difficulties in measurement and understanding in complex ecological systems. Yet, isolating temperature's influence is crucial to predicting how ecosystems will look and operate in a 'no-analog' future and to begin to integrate warming with the myriad other stressors affecting natural systems. In this dissertation, I leverage a natural stream temperature gradient (~5 - 25 °C) within a geothermal watershed to investigate the effects of temperature on stream ecosystems--with three specific questions: 1) what is the relative influence of temperature and stream flow on whole-ecosystem biomass and element storage? 2) how does temperature shape patterns of animal production across and within streams? and 3) how does temperature modify the seasonal patterns of consumer-resource interactions in stream food webs? I found stream flow to have primacy in driving the 2 orders of magnitude variation in ecosystem biomass and element storage--mediated through flow's effect on plant body size. At higher trophic levels, temperature strongly shaped the patterns of secondary production coinciding with a 45-fold increase in annual secondary production across streams. This positive relationship was mediated through covariation between temperature and basal resource availability, both across and within streams. Consumer interactions with basal resources showed differing seasonality with increasing temperature. At higher temperatures, consumer demand and resource availability were strongly coupled seasonally compared to cooler streams. Tighter coupling between consumers and resources with temperature lead to more consistent, if higher, interaction strengths through the year. My work shows temperature as an important structuring driver of ecosystem structure and process, however, a common thread through each chapter shows the influence of temperature is mediated through its interactions with other ecosystem drivers. Ultimately, as the covariation between temperature and other environmental drivers (e.g., disturbance, nutrient and light availability, etc.) shift globally, recognizing these interactions is increasingly important.Item Spanish Creek water quality(Montana State University - Bozeman, College of Letters & Science, 2019) Nealen, Carolyn Ruth; Chairperson, Graduate Committee: Greg FrancisSpanish Creek's water quality was monitored over several months, through collection of data from nine parameters. Specific data from two sites were compared to determine the impact of recreational use upon overall stream health. Macroinvertebrates were also sampled. Data was graphed and analyzed for patterns. Results suggest that Spanish Creek's water quality is Good and that recreational use does not negatively impact stream health.