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 recreational hunting of white-tailed deer on native and non-native plant abundance in northern pennsylvania(Montana State University, 2020) Supplee, Heather; Chairperson, Graduate Committee: Anthony SlominskiThe introduction and spread of non-native plant species is a large area of concern for land managers and ecologists, because these species are often capable of outcompeting native species, altering vegetative community dynamics by reducing species richness and ecosystem function. Low species diversity and disturbances in community structure are factors that may be associated with facilitating the success of non-native species. The white-tailed deer (Odocoileus virginianus) is a large herbivorous animal that can alter plant communities through a variety of mechanisms, including trampling and grazing. At high population densities, white-tailed deer can reduce plant species richness and alter plant community interactions, potentially facilitating an increase in the abundance and richness of non-native plants. Hunting is an effective tool for controlling high deer populations. In this study, I examined the impact of the presence or absence of recreational hunting on native and non-native plant species in habitats that were known to contain deer in north central Pennsylvania. I sampled native and non-native plant species richness and percent cover within 1m2 quadrats placed at 10 random locations along five transects. Two transects were in non-hunted, privately owned land and three transects were in public game lands. Each transect was sampled on five different dates, except for one transect in the private land, which was sampled four times. These transects represented a variety of habitat types. Plant species richness and percentage cover in hunted and non-hunted plots were analyzed with linear and generalized linear models using R statistical software. I found that native species richness was greater and non-native species abundance was higher at the public game lands compared to the site where hunting was prohibited. The greater native species richness in hunted sites suggests that controlling deer populations densities with hunting may play a role in maintaining the health of vegetative communities. Future studies should look at vegetative data in additional habitat types and survey sites across hunted and non-hunted lands to improve the certainty of these findings.Item An ecological risk assessment of the establishment of the asian giant hornet (vespa mandarinia) in the pacific northwest(Montana State University, 2020) Norderud, Erik D.; Chairperson, Graduate Committee: Robert K. D. PetersonThe recent introduction of the Asian giant hornet (Vespa mandarinia) in the United States in late 2019 has raised concerns about the establishment of the insect in the Pacific Northwest, and its potential deleterious effects to honey bees and their pollination services in the region. Therefore, I conducted a risk assessment to estimate the risk of establishment of V. mandarinia in Washington and Oregon on a county by county basis. To assess these risks, my assessment used the risk assessment framework put forth by the U.S. National Research Council. The risk assessment relied on the biological requirements and ecological relationships of V. mandarinia in the environments of the Pacific Northwest. I based the risk characterization on climate and habitat suitability estimates for V. mandarinia queens to overwinter and colonize nests, density and distribution of apiaries, and locations of major human-mediated introduction pathways that may increase the risk of establishment of the hornet in the counties of Washington and Oregon. My results suggest that 70 of the 75 counties in the region could be at medium to high risk of establishment by the hornet. Many of the western counties of both Washington and Oregon were estimated to be at the highest risk of establishment, mainly due to their suitable climate for queens to overwinter, dense forest biomass for nest colonization, and proximity to major port and freight hubs in the region. Considering its negative effects, these counties should be prioritized in ongoing monitoring and eradication efforts of the insect.Item The relationship between yellow toadflax (linaria vulgaris) presence, treatment history, and plant species richness near west yellowstone, montana(Montana State University, 2020) Williams, Amanda; Chairperson, Graduate Committee: Lisa RewHumans have spread plant species to novel ranges throughout history, but the rate of new introductions has drastically increased with globalization. These introduced species are often viewed as a threat to native species richness. Linaria vulgaris (yellow toadflax) was introduced to North America in the 1600s as a useful and ornamental plant and has since spread across the continent. It is mandated for control in much of the intermountain west and is thought to form monocultures to the detriment of native species. Despite L. vulgaris' long residence time on the continent, causal links to negative effects have not been established. Land managers are typically faced with a long list of species mandated for control and limited resources and thus must prioritize high impact species for control. Herbicide is the management choice for non-native plants in Yellowstone National Park, but it may have negative effects. Therefore, managers need to be sure that treatment is worthwhile, and that the effects of treatment do not exceed the effects of non-native plants. Consequently, I selected 10 sample sites in the West Yellowstone, Montana area: five with a recent history of herbicide treatment and five without. Data were collected on plant species richness and abundance within and immediately adjacent to L. vulgaris patches. Species richness and diversity did not vary between sites based on treatment history. Species diversity did increase where L. vulgaris was present, indicating that it may act as a "plus one" in communities and does not dominate where it occurs. Treatment history was not linked to a reduction in L. vulgaris abundance, but the abundance of other non-natives was greater in treated sites. These results indicate that land managers should not assume that L. vulgaris negatively effects native species richness and diversity in their location and should pair management efforts with rigorous monitoring. In the West Yellowstone area, L. vulgaris likely should not be a high priority for herbicide treatments. However, this study is observational and not sufficient to establish causal links.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 Hybridization and invasiveness in Eurasian watermilfoil (Myriophyllum spicatum): is prioritizing hybrids in management justified?(Montana State University - Bozeman, College of Agriculture, 2021) Hoff, Hannah Katherine; Chairperson, Graduate Committee: Ryan Thum; Ryan A. Thum was a co-author of the article, 'Hybridization and invasiveness in Eurasian watermilfoil (Myriophyllum spicatum): is prioritizing hybrids in management justified?' submitted to the journal 'Invasive plant science and management' which is contained within this thesis.Hybridization can play an important role in the evolution of invasiveness. Eurasian watermilfoil (Myriophyllum spicatum L.) is a widespread aquatic invasive plant species that hybridizes with native northern watermilfoil (Myriophyllum sibiricum Kom.). Previous studies have found mixed evidence for whether hybrid watermilfoil (Myriophyllum spicatum x sibiricum) and pure M. spicatum differ in vegetative growth rate and herbicide response. While several studies have emphasized variation in these traits among M. spicatum x sibiricum genotypes, variation within M. spicatum has not been considered. Therefore, it is unclear how important genetic variation within M. spicatum, versus between M. spicatum and M. spicatum x sibiricum, is in influencing invasive traits and management outcomes. If M. spicatum x sibiricum genotypes are always more invasive than M. spicatum genotypes, simply distinguishing taxa may be sufficient for identifying lake management priorities; however, if significant phenotypic overlap is observed between taxa, distinguishing individual genotypes may be important for tailoring management strategies. We performed replicated trials of a vegetative growth and 2,4-D assay to measure clonal variation in growth rate and herbicide response of M. spicatum and M. spicatum x sibiricum. Our results indicate that M. spicatum x sibiricum exhibits higher average vegetative growth than M. spicatum, whether or not it is treated with 2,4-D. We did not observe interactions between taxon and treatment or between genotype and treatment. Despite differences between M. spicatum and M. spicatum x sibiricum in average vegetative growth, there was substantial overlap between taxa. For example, we found that the fastest-growing genotype of pure M. spicatum did not differ significantly in average growth from the fastest-growing M. spicatum x sibiricum genotype. The potential for overlap between these invasive Myriophyllum taxa suggests that distinguishing and characterizing genotypes may be more informative for management than simply distinguishing between M. spicatum and M. spicatum x sibiricum.