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Adaptation of an invasive grass to agriculture: ecological and genomic evidenceSmith, Alyssa Laney 06 June 2017 (has links)
Species vary phenotypically and genetically across their environmental range limits, and this variation can influence ecological processes. Ecologically meaningful intraspecific variation might be particularly important in the context of agricultural weeds and exotic invaders, because intraspecific variation in these species might allow them to rapidly adapt to their unusually dynamic and variable environments. In a greenhouse study, we explored intraspecific variation in the size, rhizome production, and competitive ability of the global invader, Johnsongrass (Sorghum halepense), representing populations from agricultural and non-agricultural habitats across its introduced North American range. We also used these populations to explore the relationship between phenotypic variation and genomic endoreduplication responses to the common stresses herbicides, competition, and clipping. Endoreduplication occurs when plants increase their genome size by increasing their nuclear chromosome number, with some evidence showing correlations with stress response. We found that Johnsongrass plants from agricultural habitats were larger than plants from non-agricultural habitats, but there was no difference between habitats in either rhizome production or competitive ability. Two of the five herbicides we tested, primisulfuron and imazethapyr, had the strongest suppressive effects on Johnsongrass, and also stimulated the greatest rates of endoreduplication. Furthermore, agricultural populations showed higher levels of endoreduplication. We found no overall effect of competition on endoreduplication, although endoreduplication was higher for non-agricultural populations than agricultural populations. When competing with corn, but not with conspecifics, Johnsongrass roots increased endoreduplication by 13%. Clipping induced substantial endoreduplication, but there was no difference between agricultural and non-agricultural populations. Our results suggest that endoreduplication may play a role in some, but not all, stress responses in Johnsongrass. Furthermore, our results indicate that Johnsongrass has adapted in some phenotypic and genomic ways to agricultural habitats in North America. Such adaptation may play a role in this species' success as both an agricultural weed and an exotic invader. / Master of Science in Life Sciences / Agricultural weeds and exotic invasive plant species cause substantial economic and ecological impacts. Exploring the ways in which these species thrive, spread, and cope with different forms of stress contributes to our understanding of why these plants can be so successful and cause such damage. We studied how one of the world’s worst weeds and invaders of natural systems, Johnsongrass (Sorghum halepense), responded via growth and by increases in the amount of DNA in its cells to different forms of stress. We also asked whether any Johnsongrass populations appeared to have adapted to agricultural habitats. We found that Johnsongrass plants grown from seed collected from agricultural fields produced larger plants than those from non-agricultural locations (e.g., roadsides), suggesting some degree of adaptation to agricultural environments by Johnsongrass. We also found that stress from sub-lethal doses of some herbicides suppressed the growth of Johnsongrass, simultaneously stimulating more cells with increased cell DNA content, a genomic process called endoreduplication. Interestingly, there were higher rates of endoreduplication in plants from agricultural populations in the herbicide experiment, suggesting that endoreduplication may help Johnsongrass cope with stress and that agricultural populations show adaptive increases in this genomic stress response. Competition from corn or other Johnsongrass plants suppressed target Johnsongrass plants, but did not stimulate more endoreduplication in the suppressed plants. Finally, clipping reduced the size of Johnsongrass substantially, and also stimulated increased rates of endoreduplication. In general, our results indicate that Johnsongrass has adapted in some ways to agricultural habitats in North America, and that this adaptation may play a role in this species’ success as both an agricultural weed and an exotic invader.
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<b>The maintenance of ecological and evolutionary variability in small populations</b>Andrew Joseph Mularo (20379468) 07 December 2024 (has links)
<p dir="ltr">Small populations often fail to thrive, as the low levels of variation that are frequently present in small populations hinder the ability to acclimate and adapt to future environmental challenges. Despite this well-known phenomenon, many small populations persist but the factors that mediate the success of these populations are often poorly understood. In this dissertation, I conduct three studies that vary in scope and scale to better contextualize the ecological and evolutionary contexts that may lead to small population persistence. The first chapter synthesizes the theoretical and empirical evidence that allelic dominance can exert a strong influence on genetic diversity after a sharp population reduction. My findings demonstrate that dominance of one allele over another can increase additive genetic variation after a population reduction. However, maintaining the maximum amount of additive variation possible with allelic dominance may require more individuals than if two alleles have only additive effects. The second chapter focuses on elucidating the patterns of establishment and spread of three invasive anuran species that underwent sharp population declines upon their introduction to novel environments. The results from my study highlight different introduction and establishment histories that have all led to the success of each invasive species. The third and final chapter evaluates the maintenance of genomic variation in a small population with strong sexual selection, a process expected to erode variation. I tested the fit of empirical genomic and phenotypic variability data to theoretical models and found little support for the hypothesis of genic capture to maintain genetic variation. I thus discuss alternative mechanisms that may be responsible for maintaining diversity in this system. The maintenance of variation in small populations involves a complex interplay of ecological, environmental, and evolutionary forces but understanding how variation is sustained in small and imperiled populations is crucial for addressing challenges in conservation biology and the management of invasive species.</p>
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A novel algorithm for human fall detection using height, velocity and position of the subject from depth mapsNizam, Y., Abdul Jamil, M.M., Mohd, M.N.H., Youseffi, Mansour, Denyer, Morgan C.T. 02 July 2018 (has links)
Yes / Human fall detection systems play an important role in our daily life, because falls are the main obstacle for elderly people to live independently and it is also a major health concern due to aging population. Different approaches are used to develop human fall detection systems for elderly and people with special needs. The three basic approaches include some sort of wearable devices, ambient based devices or non-invasive vision-based devices using live cameras. Most of such systems are either based on wearable or ambient sensor which is very often rejected by users due to the high false alarm and difficulties in carrying them during their daily life activities. This paper proposes a fall detection system based on the height, velocity and position of the subject using depth information from Microsoft Kinect sensor. Classification of human fall from other activities of daily life is accomplished using height and velocity of the subject extracted from the depth information. Finally position of the subject is identified for fall confirmation. From the experimental results, the proposed system was able to achieve an average accuracy of 94.81% with sensitivity of 100% and specificity of 93.33%. / Partly sponsored by Center for Graduate Studies. This work is funded under the project titled “Biomechanics computational modeling using depth maps for improvement on gait analysis”. Universiti Tun Hussein Onn Malaysia for provided lab components and GPPS (Project Vot No. U462) sponsor.
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The red imported fire ant, Solenopsis invicta, in early-successional coastal plain forests: tests of distribution and interaction strengthStiles, Judith H. 15 May 1998 (has links)
The red imported fire ant, Solenopsis invicta, is an abundant and aggressive component of early-successional communities in the southeastern United States. After disturbance, it rapidly invades new habitats, and once there, it has strong competitive and predatory effects on the existing arthropod community. In upland coastal plain pine forests at the Savannah River Site in South Carolina, I conducted two studies of fire ant ecology. In my first study (chapter 1), I investigated the way in which fire ants colonize early-successional road and powerline cuts through forests, and I tested whether some of these linear habitats provided better fire ant habitat than others. I found that fire ant mound density (#/ha) was similar in narrow dirt roads and in wider roads with the same intermediate level of mowing disturbance, and that density was lower in wide powerline cuts where the vegetation is only removed every five years. Furthermore, mound density was greatest near the edges of cleared roads and powerline cuts and was also greater on the northern sides of roads and powerline cuts where there was less shading from the adjacent forest. Results from this study suggest that allowing increased shading from adjacent forest vegetation, especially along northern roadside edges, would limit the suitability of road and powerline cuts as fire ant habitat, thereby slowing invasion. In my second study (chapter 2), I examined the impact of fire ants on arthropod and plant species in early-successional forest gaps. In a tritrophic system, I tested whether the top-down effect of insect herbivore consumption by fire ants was strong enough to cascade through two trophic levels and improve plant growth and fitness. I compared this potential effect to that of other arthropod predators in the community. I found that fire ants controlled the level of tissue damage to plant leaves by herbivores, but that the damage was not severe enough to influence plant growth or fitness. Fire ants had stronger negative interactions with insect herbivores than other predators in the community, and for this reason, fire ants can be considered keystone predators. This project provides further evidence that fire ants successfully invade even small patches of early-successional habitat that exist within larger matrices of uninhabitable, late-successional forest, and that once there, they have a dramatic effect on the arthropod community. Restricting the amount of early-successional habitat within southeastern forests, either as permanent road and powerline cuts or as temporary gaps, would limit the potential for strong and detrimental effects by the invasive fire ant. / Master of Science
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Chemosensory Evaluation of Prostate Cancer CellsMartinez, Rebecca L. 14 January 2011 (has links)
Prostate cancer is the most commonly diagnosed disease and second most commonly caused death among men in America. Although much controversy surrounds the current methods of detection, PSA test and biopsy, no new methods have been approved as an effective method of detection. Biomarkers and non-invasive means of detection are being investigated everyday in hopes of discovering new information that could be of use in the prostate cancer field.
One such non-invasive technology is the use of an electronic nose. The electronic nose technology has been utilized in the agricultural, food, biomedical, and environmental. The objective of this current study is to determine the effectiveness of the electronic nose to discriminate between prostate cancer cells (DU-145 and PC-3) and non-tumor forming cells from the urinary tract (SVHUC). Specific factors that will be investigated are incubation period and cell population.
For all three cell lines, two cell populations of 75,000 and 150,000 cells were cultured and tested after 2, 8, 12, and 24 hours using a conducting polymer based hand-held electronic nose. Multivariate analysis was performed on the data and determined that the greatest discrimination between incubation periods was between 2 hours of incubation and the remaining periods of 8, 12, and 24 hour periods. This presents the idea that by 8 hours, ample volatiles were produced to be detected by the electronic nose. Additionally, when compared to one another, all three cell lines showed distinct differences. The cell lines most closely related were PC-3 and DU-145, the prostate cancer cell lines. However some variation was seen between these cell lines, which may be attributed to the presence of PSA in PC-3 cells or other factors affecting prostate cancer patients. Finally, PCA plots clearly illustrated that after 2 hours of incubation, sufficient volatiles were produced to allow the electronic nose to clearly discriminate the three cell lines from one another, demonstrating the importance of incubation period on successful discrimination.
Based on the findings that the electronic nose was effective at discriminating the three cell lines, testing was completed to determine if cell population or cell maturity had the greatest effect on discrimination. The cell lines were cultured and tested immediately using an initial cell population of the highest cell population observed after a 72 hour incubation period. The results concluded that when the cell lines were tested immediately after culturing, the Cyranose was able to detect the individual cell lines in culture while also determining a range of detection for each cell line. The range of detection for DU-145 was found to be 26,200 to 262,000 cells based on interclass m-distances of 6.829-9.170 for cell populations lower than 26,200. A range of detection of 51,400 to 514,000 cells was concluded for PC-3 cells based on interclass m-distances of 5.690-7.400 for cell populations lower than 51,400. Finally, the results showed a range of detection of 19,000 to 190,000 cells for SVHUC based on interclass m-distances of 5.520-9.076 for cell populations lower than 19,000. However, when attempting to discriminate the three cell lines against one another immediately after culture, the electronic nose was unable to make clear distinctions between the three cell lines. When testing cancerous and non-cancerous cells, incubation period of the cells should be the only factor considered. It is evident that the cells need time to metabolize and produce volatiles so that the electronic nose can clearly distinguish these cells from one another in culture. / Master of Science
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Toward a More Integrative Approach to Quantifying the Ecological Impacts of Invasive PlantsTekiela, Daniel 04 May 2016 (has links)
Invasive species are reported as one of the top current and future concerns for the health and functioning of native ecosystems. In response, identification of invasive plant impacts are one of the top most studied aspects of plant invasions. Yet we still know very little about invasive plant impacts, and many land managers remove invasive plants not because of known negative impacts, but because of the general negative connotation associated with invasions. Here, I develop and utilize integrative methods to more holistically measure the ecological impacts of invasive plants. I develop a meta-analysis of current invasive plant impact literature, I integrate independent ecosystem metrics into holistic measures of total ecological impact, I examine the potential for legacy and temporal effects in newly established and recently managed invasions, and I measure ecological impact of co-invaded ecosystems. Through these studies, I find that magnitude, and not direction, of impact better represents actual ecosystem changes when evaluating invasions holistically. I also find invasive plant management may not only fail to remove long term legacy effects, but may in some cases further negatively impact the plant community. Finally, I find that co-invaded systems are not intrinsically worse off than single invaded systems. Collectively, these studies help to better our understanding of the impacts of invasive plants and their implications for management, and show that simple attempts at eradication may not always be desirable. / Ph. D.
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Non-invasive assessment of stress hormones, parasites, and diet, using scat of five felid species in Belize, Central AmericaMesa Cruz, Jose Bernardo 02 June 2014 (has links)
Many Neotropical felid species, such as jaguars, are threatened with extinction due to habitat fragmentation and/or human persecution. Human activities around protected areas in Belize, Central America, are increasing and so are levels of human-felid conflict. Potential consequences of this conflict are an increase in stress impacting health, diet shifts, or heightening of animal aggression. The goal of this work was to assess the effects of human-modified habitats on native felids by comparing fecal glucocorticoid metabolite (FGM) concentrations, endoparasite species richness (ESR), and diet using non-invasive scat sampling in a protected forest vs. surrounding non-protected areas in Belize. Field studies relying on non-invasive fecal hormone monitoring are subject to potential hormone degradation in samples exposed to the environment. Therefore I conducted immunoassay and environmental validations for measuring FGM in jaguars (Panthera onca).
In the field, I collected scat using a detector dog, identified samples using DNA, retrieved parasite propagules with a flotation technique, and identified prey remains by morphology. I detected five felids: jaguar, puma, ocelot, jaguarundi and domestic cat. FGM concentrations were higher in pumas and jaguarundis than in the other felids. I found no livestock remains in felid scats. ESR was similar across felid species. Domestic cats were found only in human-modified areas. This results provide a baseline on adrenal activity, prey consumption, and endoparasites in felids of Belize. These findings could be used for comparisons to populations thought to be affected by human activities across Belize and in neighboring countries. / Master of Science
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Organ Viability Assessment in Transplantation based on Data-driven ModelingLan, Qing 03 March 2020 (has links)
Organ transplantation is one of the most important and effective solutions to save end-stage patients, who have one or more critical organ failures. However, the inadequate organs for transplantation to meet the demands has been the major issue. Even worse, the lack of accurate non-invasive assessment methods wastes 20% of donor organs every year. Currently, the most frequently used organ assessment methods are visual inspections and biopsy. Yet both methods are subjective: the assessment accuracy depends on the evaluator's experience. Moreover, repeating biopsies will potentially damage the organs. To reduce the waste of donor organs, online non-invasive and quantitative organ assessment methods are in great needs.
Organ viability assessment is a challenging issue due to four reasons: 1) there are no universally accepted guidelines or procedures for surgeons to quantitatively assess the organ viability; 2) there is no easy-deployed and non-invasive biological in situ data to correlate with organ viability; 3) the organs viability is difficult to model because of heterogeneity among organs; 4) both visual inspection and biopsy can be applied only at present time, and how to forecast the viability of similar-but-non-identical organs at a future time is still in shadow.
Motivated by the challenges, the overall objective of this dissertation is to develop online non-invasive and quantitative assessment methods to predict and forecast the organ viability. As a result, four data-driven modeling research tasks are investigated to achieve the overall objective:
1) Quantitative and qualitative models are used to jointly predict the number of dead cells and the liver viability based on features extracted from biopsy images. This method can quantitatively assess the organ viability, which could be used to validate the biopsy results from pathologists to increase the evaluation accuracy.
2) A multitask learning logistic regression model is applied to assess liver viability by using principal component analysis to extract infrared image features to quantify the correlation between liver viability and spatial infrared imaging data. This non-invasive online assessment method can evaluate the organ viability without physical contact to reduce the risk of damaging the organs.
3) A spatial-temporal smooth variable selection method is conducted to improve the liver viability prediction accuracy by considering both spatial and temporal effects from the infrared images without feature engineering. In addition, it provides medical interpretation based on variable selection to highlight the most significant regions on the liver resulting in viability loss.
4) A multitask general path model is implemented to forecast the heterogeneous kidney viability based on limited historical data by learning the viability loss paths of each kidney during preservation. The generality of this method is validated by tissue deformation forecasting in needle biopsy process to potentially improve the biopsy accuracy.
In summary, the proposed data-driven methods can predict and forecast the organ viability without damaging the organ. As a result, the increased utilization rate of donor organs will benefit more end-stage patients by dramatically extending their life spans. / Doctor of Philosophy / Organ transplantation is the ultimate solution to save end-stage patients with one or more organ failures. However, the inadequate organs for transplantation to meet the demands has been the major issue. Even worse, the lack of accurate and non-invasive viability assessment methods wastes 20% of donor organs every year. Currently, the most frequently used organ assessment methods are visual inspections and biopsy. Yet both methods are subjective: the assessment accuracy depends on the personal experience of evaluator. Moreover, repeating biopsies will potentially damage the organs. As a result, online non-invasive and quantitative organ assessment methods are in great needs. It is extremely important because such methods will increase the organ utilization rate by saving more discarded organs with transplantation potential.
The overall objective of this dissertation is to advance the knowledge on modeling organ viability by developing online non-invasive and quantitative methods to predict and forecast the viability of heterogeneous organs in transplantation. After an introduction in Chapter 1, four research tasks are investigated. In Chapter 2, quantitative and qualitative models jointly predicting porcine liver viability are proposed based on features from biopsy images to validate the biopsy results. In Chapter 3, a multi-task learning logistic regression model is proposed to assess the cross-liver viability by correlating liver viability with spatial infrared data validated by porcine livers. In Chapter 4, a spatial-temporal smooth variable selection is proposed to predict liver viability by considering both spatial and temporal correlations in modeling without feature engineering, which is also validated by porcine livers. In addition, the variable selection results provide medical interpretations by capturing the significant regions on the liver in predicting viability. In Chapter 5, a multitask general path model is proposed to forecast kidney viability validated by porcine kidney. This forecasting method is generalized to apply to needle biopsy tissue deformation case study with the objective to improve the needle insertion accuracy. Finally, I summarize the research contribution and discuss future research directions in Chapter 6. The proposed data-driven methods can predict and forecast organ viability without damaging the organ. As a result, the increased utilization rate of donor organs will benefit more patients by dramatically extending their life spans and bringing them back to normal daily activities.
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An Investigation of the Factors that Facilitate and Inhibit the Range Expansion of an Invasive PlantFletcher, Rebecca A. 27 November 2019 (has links)
All species on Earth occupy limited geographic space. More than a century of observational, experimental, and theoretical work investigating the factors that drive species distributions have demonstrated the importance of the interactions between abiotic, biotic, and demographic factors in determining why species are found where they are. However, it is still unclear when and where these factors interact to set species range limits. Filling the existing knowledge gaps is imperative for the accurate predictions of how species will respond to global change, and particularly for invasive species, many of which are expected to benefit from global change. Here, I sought to investigate the mechanisms that enable, as well as limit, the range expansion of the globally invasive plant Sorghum halepense (L.) Pers. (Johnsongrass). I performed a series of field and laboratory experiments to study population and range dynamics throughout Johnsongrass's North American distribution, and test for the effects of climate, local habitat, and competition on multiple functional traits. I found Johnsongrass consistently demonstrated impressive performance across varying environments, often growing more than 3 m tall, producing hundreds of flowering culms within a single growing season, and maintaining positive population growth rates, even under intense competition with resident weeds. I also found evidence that seed germination has adapted to varying climates encountered during Johnsongrass's range expansion resulting in a shift in the germination temperature niche from warmer to cooler as Johnsongrass spread from warmer climates in the south to more temperate climates in higher latitudes. This shift in the germination temperature niche may have been an important contributing factor in the range expansion of Johnsongrass by enabling the optimization of seed germination in varying climates. On the other hand, results from a field study suggested a possible trade-off between flowering time and growth in populations originating from the range periphery (i.e., range boundary) which may be limiting, or slowing, continued range expansion of Johnsongrass. Together, the outcomes of this work contribute to our understanding of the factors involved in the distribution of species, which is a fundamental goal of Ecology, and essential to accurately predict how invasive species will respond to global change. / Doctor of Philosophy / Invasive species threaten our natural ecosystems, our agricultural systems, and even our infrastructure, and we spend billions of dollars each year attempting to control them and reduce their negative impacts. Climate change, habitat destruction, and other forms of global change, will benefit many of these species, magnifying their impacts and promoting their invasion into new territories. Because of the damaging effects of invasive species, and the costs to control them, it is imperative that we are able to predict how they will respond to global change so that we can improve plans to reduce their impact and spread. First, we need to understand the processes that promote their invasion across large swaths of land. Just as importantly, we must study the processes that prevent their invasion of certain areas. Here, I investigated some of the processes that have facilitated, as well as hampered, the spread of the invasive plant Johnsongrass. For this work, I used Johnsongrass plants originating from different habitats, including regions where Johnsongrass is highly invasive and those where Johnsongrass is very rare. I found Johnsongrass originating from regions where it is highly invasive were able to grow very large and produce thousands of seeds that were able to germinate under a range of conditions. These traits may have contributed to the invasion success of this species. However, I found a different pattern for plants that originated from regions where Johnsongrass is rare. These plants reached reproductive age earlier and grew smaller across all environmental conditions, potentially due to the less hospitable climates of these range edges. These findings allow us to project into future climate change scenarios, because it is likely that, as temperatures warm, invasive species will be able to invade new regions, where they will impact the work of conservationists, natural resource professionals, agricultural produces, and other land managers.
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Essays on the Non-market Valuation and Optimal Control of Bio-invasions in Urban Forest ResourcesSiriwardena, Shyamani Dilantha 21 February 2017 (has links)
This dissertation consists of three essays, of which, two involve assessing the value of tree cover in urban communities and the other evaluates cooperative management of an invasive species by urban communities. The first chapter summarizes the three topics and briefly describes the motivation, methods applied and main conclusions in each study.
Chapter 2 presents a meta-analysis of hedonic property value studies on the value of tree cover. A meta-regression was performed using implicit value estimates for tree cover at property-level from various locations in the U.S. along with auxiliary data of county-level tree cover to investigate the relationship between tree cover and implicit-price estimates for residential properties. The study found that on average 35 percent and 40 percent tree cover respectively at property-level and county-level optimize the benefits to the property owners in urban areas. These results provide insights to forward-looking communities to adapt their tree planting and protection efforts to lessen climate-induced impacts.
Chapter 3 applies a first-stage Hedonic property price model to estimate preference for tree cover in urban communities using single-family house sales data from multiple property markets across the U.S. The study analyses how home owners' preference for tree cover vary across the landscape and across cities. Further, it identifies what factors affect these variations via the general inferences obtained from an internal meta-analysis. The study confirms the heterogeneity of preferences as affected by the differences in the abundance of tree cover in study locations, regional differences and household characteristics. These findings add to the hedonic literature and provide useful information for future urban planning.
Chapter 4 focuses on cooperative management of invasive species in landscapes with mixed land ownerships. This study analyzes the effect of the land ownership on the management efforts between an infested municipality and an uninfested municipality when a transferable payment scheme is involved in the cooperative agreement. A dynamic optimization problem was set up to evaluate the case of Emerald ash borer (EAB) control in multiple jurisdictions in the Twin Cities, Minnesota. The results suggest that when the infested municipality has more public lands and when the transfer payments are efficiently used to implement greater control, the municipalities are more likely to commit to bargaining, and smaller transfer payments paid over a longer span of time are sufficient for optimal control of the spread of invasive species across the municipalities.
The last chapter concludes the three studies and discusses the insights for future research. / Ph. D. / Mountain pine beetles (Dendroctonus ponderosae) are a native insect that has decimated millions of hectares of mature pine forests in western North America. The purpose of this study was to investigate, using GIS-derived variables, biophysical and climatic factors that have influenced past mountain pine beetle insect outbreaks, as evident by beetle-induced tree mortality in the Crown of the Continent Ecosystem (CCE) from 1962 to 2014. Specific objectives of this study were to determine how selected biophysical variables (slope, aspect, elevation, and latitude), regional climate variables (temperature, precipitation, and drought) and global climate oscillations (ENSO, PDO, NAO, AO, and PNA) relate to bark beetle infestations in the Crown of the Continent Ecosystem from 1962 through 2014, as measured by aerial surveyrecorded tree mortality. We sought to contextualize the results of the statistical models with historical data to further understand the relationship between increases and decreases of tree mortality by comparing these trends to geopotential height and sea-surface temperatures that may influence CCE climate. Our work revealed first, that while the aerial survey data has important limitations, overall it is a useful dataset for analyzing historical spatio-temporal patterns of insect infestations. Second, there appears to be a link between local biophysical factors, such as latitude, elevation, and winter precipitation (as opposed to global climate factors) and tree mortality within the CCE. Local climate analysis revealed the importance of winter precipitation to be the biggest influence of MPB decrease or increase along with lower geopotential heights during a decline in MPB spread over the CCE. Finally, a combination of a negative PDO and El Niño was important in forecasting a decline in MPB spread, as shown by damage, during a given year. This is the first study to use aerial survey data in a geospatial analysis incorporating biophysical variables for the US portion of the Crown of the Continent Ecosystem. Additionally, this study is unique to explore the potential relationship between global teleconnections and regional climate in the CCE area, and the spatio-temporal extent of mountain pine beetle infestations.Urban trees have become a key resource in building sustainable communities. Knowledge of preferences for trees, costs and benefits of trees, and how trees are managed by private and public landowners, is indispensable in making targeted planning that would fulfill the economic, social and environmental objectives of the urban communities This dissertation explores on these topics in three papers. Chapter 1 summarizes the three topics and briefly describes the motivation, methods applied and main conclusions in each study. Chapter 2 presents a meta-analysis that combines the non-market value estimates for tree cover from previous hedonic studies from various locations in the U.S. along with auxiliary data to investigate the relationship between the level of tree cover and value estimates. The study found that on average 35% and 40% tree cover respectively at property-level and county-level optimize the benefits to the property owners. Chapter 3 analyses how home owners’ preferences for trees vary across the landscape in multiple cities in the U.S., and the results are systematically summarized via an internal-meta analysis. The study confirms the preference heterogeneity across the landscape and found that the relative abundance of tree cover in study locations, regional differences and household characteristics affect the preferences. Chapter 4 develops a dynamic optimization model to study how private and public land ownership in local municipalities affects the cooperative management of urban trees to control the Emerald ash borer (EAB) infestation in Twin Cities, Minnesota. The results suggest that when an infested municipality has more public lands and when the transfer payments are efficiently used to implement greater control, the municipalities are more likely to commit to bargaining agreements that last for longer period of time. Results from the three studies provide insights to forward-looking communities to adapt their tree planting and protection efforts to lessen climate-induced impacts. The last chapter concludes the three studies and discusses the insights for future research.
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