Theses and Dissertations at Montana State University (MSU)
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Item The role of terpenoids and phenolics in controlling ecological impacts of hemlock wooly adelgid in the great smoky mountains national park(Montana State University, 2021) Branum, Emily Renaee; Chairperson, Graduate Committee: Scott PowellThe hemlock woolly adelgid (Adelges tsugae) is an invasive pest in the eastern United States where they have been colonizing and feeding on eastern hemlock oleoresin, initiating death and stand decline. Eastern hemlock stand reductions are important in the Great Smoky Mountains National Park because they host a notoriously biodiverse ecosystem, which is popular among tourists and economically supports the neighboring communities of Pigeon Forge and Gatlinburg, Tennessee. Rapid decline of eastern hemlock and their associated microclimates affect many abiotic and biotic aspects of the surrounding ecosystem. Although dependent on abiotic factors and metabolically costly to produce, terpenoids and phenolics have repellency potential in sufficient concentrations to prevent the loss of eastern hemlock and their associated ecological impacts. Therefore, I conducted a comprehensive, interpretive literature review to assess which terpenoids and phenolics are released after hemlock woolly adelgid herbivory, the extent to which they are produced, and if they lead to herbivory reductions. That knowledge is then related to ecological impacts caused by their release. Although not actually performed, I present sampling and analysis methods to achieve a representative terpenoid and phenolic profile followed by probable results, a discussion of current and potential management strategies, and subjects of future study. Overall, my paper is informative in nature and could provide insight and direction in the development of resistance-breeding, mitigation, and conservation programs. Regardless of which strategy is chosen, adequate monitoring, management, and restoration is needed to preserve eastern hemlock. Otherwise, the hemlock woolly adelgid population will continue to expand, negatively affect hemlocks, and degrade the Great Smoky Mountain National Park ecosystem.Item Resilience of sagebrush steppe plants nine years after fire and soil disturbance in southwest montana(Montana State University, 2021) Newell, Isaac TodhunterSagebrush steppe in the western United States faces an increasing risk of degradation and overall habitat loss from land use and climate change. One important result of these drivers is the spread of the nonnative annual grass, Bromus tectorum. In many of these grasslands, B. tectorum has altered fire regimes through a positive feedback loop in which increased B. tectorum leads to more severe and frequent fires, and consequently increased B. tectorum cover. This ultimately displaces native flora and fauna, moving grasslands away from historic structure and function. However, in the northern portion of the sagebrush steppe, native communities were recently found to be resilient to fire 3 years post-fire, but not to soil damage. I revisited the study site (Red Bluff, Montana, US) to evaluate how this plant community has responded to fire and soil damage 9 years after disturbance. I sampled the same three treatments: an area burned by the 2012 Red Bluff fire, an adjacent unburned area, and a bulldozed firebreak between the two. In each treatment, 28 x 1m2-plots were sampled along three transects running parallel to the fire break. Percentage cover of each species, litter, bare ground, rock, and manure were recorded and analyzed for differences in richness, ground cover, and Bromus tectorum cover, as well as alpha- and beta-diversities, using generalized linear models. Nearly a decade after disturbance, fire and soil damage still significantly affected species richness (p = 0.05) and species composition (p = 0.02). Both the unburned and burned treatments had a greater cover of native species than did the bulldozed plots (p < 0.01). Bromus tectorum was the most abundant species in the bulldozed treatment, with 186.7% greater relative abundance than unburned treatment, and 107.6% greater than the burned treatment (p < 0.01). This shows that while the plant community is resilient and resistant to nonnative invasion after fire, it is much less so after soil disturbance. This may have implications on future applications of fire breaks and the way they are managed after fire, as well as other mechanical disturbances to soil structure.Item The impact of elevation and proximity to trails on plant biodiversity in mountain ecosystems surrounding Flagstaff, AZ, USA(Montana State University - Bozeman, College of Agriculture, 2019) Morford-Graziano, Dawn Marie; Chairperson, Graduate Committee: Scott PowellThe objectives of this project were to compare biodiversity along an elevation gradient in the mountains surrounding Flagstaff, Arizona. In addition, identify the presence or absence of four specific non-native species being monitored using the Mountain Invasion Research Network (MIREN) protocol: common yarrow (Achillea millefolium), red clover (Trifolium pratense), white clover (Trifolium repens), narrowleaf plantain (Plantago lanceolata). The study used T-shaped transects at randomly selected sampling locations to collect data on richness and abundance of plant species up to 22 m from four hiking trails. Measured sample location was the middle point of the trailside or "near" sample unit. The "near" sample unit (2 m deep * 10 m parallel) was parallel with the trail. The other two sample units "middle" and "far" were perpendicular to the trail, starting 2 m from the measured sample location. Simpsons (1-D) and Shannon's Index were used to determine alpha biodiversity (diversity within a community (Magurran & McGill, 2011) along the elevation gradient. Jaccard Index and Morista-Horn Index used to compare dissimilarity of beta diversity (diversity between communities (Magurran & McGill, 2011)) between elevation zones and proximity to the trail. Dissimilarity is the amount of difference between communities. The study demonstrated species richness decreased as sample location elevation increased. Species richness also decreased as the distance from the trail increased. Simpson's and Shannon's biodiversity indices both showed a statistically significant difference in biodiversity values decreasing with an increase in elevation. Dissimilarity index values for both beta diversity indices indicated a statistically significant difference in dissimilarity based on proximity to the trail. The presence of common yarrow was only found at two sampling locations preventing further analysis. All trails had similar relative abundances but the dominant species along each trail was different. Elevation plays a determining role in the richness and diversity of species in mountain ecosystems surrounding Flagstaff, Arizona.Item Environmental DNA (eDNA) analysis as a survey tool in natural spring and stock tank biomonitoring(Montana State University - Bozeman, College of Agriculture, 2019) Smith, Kelsey Anne; Chairperson, Graduate Committee: Scott PowellRecent research has shown the viability of environmental DNA (eDNA) in identifying the presence of organisms in freshwater ecosystems. Environmental DNA includes the DNA from an organism that is collected from environmental samples, instead of from the organism itself; by collecting water samples and analyzing this eDNA through metabarcoding techniques, the presence of species in a given ecosystem can be established. However, there is limited research indicating the feasibility of eDNA as a survey tool in water sources such as springs and stock tanks. Because of the scarcity of water in the high desert landscape of central Arizona, natural springs and man-made stock tanks, used as water sources for open range cattle, play an important role in the functioning of the ecosystem, and are a stopping point for many vertebrate species. Therefore, we address the question of whether eDNA analysis is a viable survey tool in monitoring vertebrate species presence in springs and stock tanks within the Prescott National Forest in the Arizona central highlands. Water samples were collected in 250 mL and 500 mL containers, and were filtered to capture fine particles and cells greater than 0.45 ?m. These particles were then amplified with universal primers for 16S sections, which are conserved in vertebrates as part of the rRNA gene. Current methodologies have shown that the 16S rRNA gene is effective in recognizing vertebrate DNA. The 16S rRNA metabarcoding technique used in this project detected the presence of species that are common to the Prescott National Forest, including species of bear, deer, and squirrel. Additionally, this eDNA metabarcoding technique detected the American bullfrog, which is an invasive species in the Southwestern United States. Our detection of the invasive American bullfrog represents a next step in better monitoring presence and removing the species from ecosystems throughout the region. Our results suggest eDNA metabarcoding is an effective tool in assessing species presence at natural springs and stock tanks, and should continue to be used for further research focused on biomonitoring in other water sources.Item Remote sensing for wetland restoration analysis: Napa-Sonoma Marsh as case study(Montana State University - Bozeman, College of Agriculture, 2019) Byrne, Charles; Chairperson, Graduate Committee: William KleindlHuman-caused ecosystem change and habitat loss is a major worldwide concern. Wetland loss has been remarkable worldwide and in the US. In the San Francisco Bay system, the largest estuary on the eastern rim of the Pacific Ocean and a biodiversity hotspot, more than 90 percent of the wetlands have been lost to urban development, salt production and agriculture, a loss that primarily occurred in the century following 1850. Restoration is our primary mechanism for confronting this challenge. While wetland restoration design has advanced dramatically since the early designs of the 1980s, restoration analysis and evaluation remain challenges that until now have wholly or primarily required on-site sampling. This is a major challenge for larger restoration projects, such as the Napa-Sonoma Salt Marsh restoration in California. Previous studies have indicated that the Normalized Difference Vegetation Index (NDVI) has been used in some restoration analyses with apparent success, but data is limited. To better understand its potential, this study examines issues in restoration analysis in the context of wetland restorations. By comparing pre- and post-restoration remote sensing data, I found that two sites in the Napa-Sonoma Marsh restoration demonstrated mixed NDVI results and that changes depended on subarea and whether median or maximum NDVI was analyzed. The mixed results are explained by several factors: the inherent limitations of NDVI; the large restoration size; the fact that wetlands, less vegetated, present special challenges for analysis; and the fact that it is early in the post-restoration period. The case study supports the use of remote sensing and GIS for restoration analysis and evaluation, but also emphasizes their current limitations. Many of these limitations, which hinge on the complexity of the potential data involved, are likely to be addressed in the next generation as the relevant technology continues to develop.Item Ventenata (Ventenata dubia) control treatments on the Crow Reservation(Montana State University - Bozeman, College of Agriculture, 2023) Fighter, Zachariah Zachary Zane; Chairperson, Graduate Committee: Jane M. Mangold; Scott Powell (co-chair)Ventenata (Ventenata dubia) is a non-native winter annual grass that has been of increasing concern in southeastern Montana. Research has shown that ventenata can increase rapidly, lower forage production, and reduce biodiversity. This project is located in southeastern Montana, in Bighorn County on the Crow Reservation. Two studies were conducted to understand control options and monitoring of those treatments post-treatment. A field study tested two herbicides and a soil amendment for the management of ventenata. At four sites, indaziflam and imazapic at two water carrier rates and two rates of an organic soil nutrient amendment were tested using a split-plot randomized block design. The water carrier rates were meant to mimic aerial and ground applications. Herbicides were applied using a hand-held boom sprayer pressurized by CO 2. Soil amendment was hand-broadcasted. In late June 2022 (first growing season post-treatment), sampling consisted of randomly placing 3, 20 cm x 50 cm frames in each split-plot and estimating cover by species along with litter and bare ground. Imazapic and indaziflam provided the highest reduction of ventenata, regardless of water carrier rate. Across the four sites, imazapic reduced ventenata cover to <1% while indaziflam reduced cover to 4%, compared to the control which was 38%. The soil amendment reduced ventenata to 25% at two sites, suggesting it may not be as promising of a control method as the herbicides. Application rates for all treatments did not differ, suggesting that aerial application of the herbicides may provide just as good of control as ground application. This is encouraging for the prospect of managing ventenata aerially. At one of the sites, a remote sensing time series study using an Unmanned Aerial Vehicle (UAV) with a multispectral sensor was used to understand differences in the Normalized Difference Vegetation Index (NDVI) between herbicide sprayed and non-sprayed plots. Findings indicate that there is a shift in NDVI in late June where sprayed plots peak in NDVI and remain green longer into the season than non-sprayed plots. This study provides control options that land managers in southeastern Montana can consider using for ventenata management.Item Understanding mechanisms of invasion and restoring lands impacted by non-native annual grasses(Montana State University - Bozeman, College of Agriculture, 2020) Majeski, Michelle Lynn; Chairperson, Graduate Committee: Jane M. Mangold; Catherine Zabinski, Lisa J. Rew and Jane Mangold were co-authors of the article, 'Ventenata dubia growth responds to field soil inocolum but not phosphorous and potassium treatments' which is contained within this thesis.; Catherine Zabinski, Lisa J. Rew and Jane Mangold were co-authors of the article, 'Ventenata dubia was associated with perennial grasses, bare ground and soil potassium concentration' which is contained within this thesis.; Stacy C. Simanonok, Zach Miller, Lisa J. Rew and Jane Mangold were co-authors of the article, 'Spring seeding provides a seasonal priority effect for Pseudoroegneria spicata in Bromus tectorum-invaded rangelands' which is contained within this thesis.European settlement and development of rangelands in the western U.S. has led to a shift in vegetation from native species to introduced species, some of which have become weedy and invasive. Effects of invasive plant species can vary but often include replacing native vegetation, altering ecosystems, affecting wildlife that relied on the native plants for food and shelter, and toxicity to livestock. Two introduced annual grasses of concern are Ventenata dubia and Bromus tectorum. These grasses are at different stages in their invasion in the western U.S. Ventenata dubia is a recent invasive species in the past ten years and B. tectorum has been dominant in the Intermountain West since the mid-1900s. Three independent studies were conducted to understand characteristics of V. dubia invasion and to test whether a seasonal priority effect could be shifted to Pseudoroegneria spicata to outcompete B. tectorum in range/pasturelands. A full-factorial design was executed in a greenhouse setting to examine if a plant-soil feedback contributes to V. dubia invasion and if V. dubia preferred specific nutrients for growth. Ventenata dubia biomass, shoot height and number of leaves and tillers (per plant) were higher when grown with field soil inoculum compared to sterilized greenhouse soil. Ventenata dubia growth varied among nutrient treatments, but trended higher with a full nutrient solution. A nested observational study was conducted to examine abiotic and biotic characteristics associated with V. dubia infestations. Ventenata dubia was positively associated with non-native perennial grasses and negatively associated with native perennial grasses, bare ground/rock and soil potassium concentration. A randomized split-plot design was performed in B. tectorum-infested range and pasturelands to test whether timing of herbicide application and seeding of P. spicata could create a seasonal priority effect for P. spicata. Bromus tectorum had lower cover and biomass (per m2) with spring herbicide application. Higher P. spicata density, cover and biomass resulted with spring seeding after B. tectorum was reduced. These studies show that established and seeded native perennial grasses can compete with nonnative, invasive annual grasses. When existing management tools (herbicide and revegetation) are applied in a different way, native perennial grasses benefit.Item An experimental approach to understanding how Bromus tectorum will respond to global climate change in the sagebrush-steppe(Montana State University - Bozeman, College of Agriculture, 2016) Larson, Christian Douglas; Chairperson, Graduate Committee: Lisa J. RewGlobal climate change, including elevated atmospheric CO 2 concentrations, increases in global surface temperatures, and changes in resource availability, has significant consequences for global plant communities, one of which is the expansion of invasive species. The invasive grass species Bromus tectorum dominates areas of the North American sagebrush-steppe. In these areas, B. tectorum responds positively to elevated nutrients after fire and a positive feedback with fire has been initiated. Bromus tectorum dominance and its positive response to fire are limited by cold and moist climates. Global climate change is predicted to expand the climate suitability for B. tectorum dominance, as well as that of its response to fire. Using a field study and controlled setting experiments, I investigated this prediction. In a cold and moist southwestern Montana sagebrush-steppe, my field experiment assessed the response of B. tectorum and the native plant community to increased growing season temperatures, decreased growing season precipitation, and a prescribed burn. We found that both B. tectorum and a dominant native perennial grass, Pseudoroegneria spicata, responded negatively to experimental warming, and warming and drying. Bromus tectorum's response to fire was limited to an increase in individual fecundity across the climate scenarios and compensatory growth in warm and dry conditions. In controlled settings, using differing densities of B. tectorum and P. spicata, I performed replacement series experiments that altered temperature, water availability, nutrient availability, and, secondly, atmospheric CO 2 concentration and water availability. Bromus tectorum competitiveness was enhanced by warmer and drier conditions and elevated nutrient availability. When grown in monoculture, both species responded positively to elevated CO 2. When grown in competition, elevated CO 2 increased P. spicata's already significant suppressive effect on B. tectorum. This effect was magnified when soil moisture was limited. Due to B. tectorum's significant negative response to the field climate treatments, its limited response to fire, and the significant suppressive effect of the native grasses in both experiments, especially in elevated CO 2, I conclude that similar future climate scenarios will not promote the expansion of B. tectorum dominance and its positive response to fire within the cold and moist northern region of the sagebrush-steppe.Item Using ecological theory to guide the implementation of augmentative restoration(Montana State University - Bozeman, College of Agriculture, 2004) Bard, Erin Christina; Co-chairs, Graduate Committee: Roger L. Sheley and Jeff JacobsenInvasive organisms are now considered the second worst threat to native biological biodiversity, behind habitat loss and fragmentation. Successful control of invasive plants can have unexpected impacts on native plants and wildland systems. Therefore, it is important for managers of invasive species to become increasingly concerned with more than target invaders, but also ecological mechanisms and processes like invasion resistance, environmental heterogeneity, and succession that direct plant community dynamics. Augmentative restoration is a management approach that augments existing ecological processes by selectively repairing and replacing those processes that are damaged or missing thereby directing plant communities in a desirable direction. Our overall objective was to test the concept of augmentative restoration. Our overall hypothesis was that successional processes occurring at high levels could be augmented by selectively repairing or replacing successional processes that occur at low levels to increase desired species composition. In a split plot design with 4 replications at 3 sites, 8 factorial treatment combinations from 3 factors (shallow tilling, watering, and seeding) were applied to whole plots, and 2,4-D was applied to sub plots. Cover and density of seeded species, Centaurea maculosa, and Potentilla recta as well as existing native and exotic forbs and grasses were sampled in 2002 and 2003 to produce pretreatment and post-treatment data. ANCOVA was used to analyze cover and density data using pre-treatment data as a baseline covariate. Data indicated that areas with high percent bare ground required seeding and watering to increase seeded species and native forbs, while seeding and tilling increased seeded species and native forbs in areas of high soil moisture. C. maculosa, P. recta, and exotic forbs decreased in response to tilling and 2,4-D. Exotic and native grasses increased in response to tilling and 2,4-D indicating that grasses may have reproduced primarily vegetatively. This data provided evidence that augmentative restoration could provide managers with an ecological framework to develop restoration procedures that address invasion resistance, environmental heterogeneity, and succession in order to enhance native forbs and grasses as well as improve the emergence of seeded species to increase desired plant composition in wildlands damaged by invasive plants.