UMD Theses and Dissertations
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Item PHYLOGENOMICS, LIFE-HISTORY EVOLUTION AND TAXONOMY OF LEAF MINING MOTHS (LEPIDOPTERA: GRACILLARIOIDEA)(2010) Kawahara, Akito; Mitter, Charles; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Phytophagous insects dominate the terrestrial earth. While many are external plant feeders, a large diversity of insects specialize on feeding internally within plants. This study constructs one of the first phylogenies of the diverse leaf-mining moth superfamily Gracillarioidea, and examines broad patterns of life history evolution. This dissertation begins with a short introduction (Chapter 1), before a molecular phylogenetic analysis of the Gracillarioidea utilizing over 14,800 nucleotides (Chapter 2). Results indicate that 1) Douglasiidae probably does not belong in Gracillarioidea; 2) the phylogenetic position of Bucculatricidae in Gracillarioidea is generally weak, but strong when non-synonymous changes are analyzed alone; 3) deep divergences in the superfamily are difficult to resolve even with 21 genes; and 4) four strongly supported clades, roughly corresponding to Kumata's classifications were recovered in the Gracillariidae. Chapter 3 is a preliminary examination of life-history evolution in Gracillariidae, focusing on the "top down" effects from parasitoids that may have shaped the life histories of gracillariids. Results include: 1) larval traits (larval habit, cocoon ornamentation) is conserved on phylogeny, but traits associated with hosts are less so; 2) that host shifts in gracillariids are more common among closely related plants, and that closely related insects feed on closely related hosts; 3) blotch mining is the ancestral condition of mine form in Gracillariidae; 4) tentiform blotch mining, a modification of the simple blotch mine, may be an evolutionary innovation against parasitoids. The final three chapters focus on the taxonomy, life-history, and morphology of several gracillariids, including the description of three new species. The central theme is Phyllocnistis, a diverse, yet poorly studied serpentine mining gracillariid genus.Item THE INFLUENCE OF LAND-USE, ENVIRONMENT, AND SOCIOECONOMIC FACTORS ON TREE SPECIES DISTRIBUTION IN BALTIMORE, MARYLAND.(2009) Mead, Kimberley Ellen; Sullivan, Joseph H.; Plant Science and Landscape Architecture (PSLA); Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)With the exponential growth in human population and rapid increase in global urbanization, understanding changes in community dynamics and structure in human dominated landscapes is essential, yet, rarely studied. To determine what factors account for tree species composition and distribution in an urban setting, data from the 1999 UFORE Model vegetation survey of Baltimore, Maryland was analyzed. There was a diverse arboreal population found, comprised primarily of species native to the area. Detrended correspondence analysis did not show a clear pattern of species assemblages based on land-use, possibly indicating a homogenization of conditions across the urban environment. In canonical correspondence analyses, species distribution could not be explained by socioeconomic factors, however, there was a significant relationship of tree species assemblages and the physical environment, specifically with percent impervious surface cover. The amount of variance accounted for was small indicating that other factors may be involved in determining tree species distribution.Item Effects of nitrogen and calcium on photosynthesis and metabolic activity in Acer saccharum in the Catskill Mountains(2008-03-31) Behling, Shawna Joy; Sullivan, Joseph H; Plant Science and Landscape Architecture (PSLA); Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The Catskill Mountains in southern New York have received some of the most acidic rainfall in the country for the past 50 years. Acid deposition on these thin soils may deplete the concentration of calcium and other essential ions in the soil solution and mobilize other ions that can be harmful to sugar maple (Acer saccharum) rooting systems. The effects of fertilizers on the metabolism and photosynthesis rates of sugar maple are of great interest to both farmers and ecologists. In this study, 12 plots in a 60-year-old sugar maple dominated forest were treated with no fertilizer, nitrogen, calcium, or nitrogen and calcium together. Photosynthesis was measured with a LiCor 6400. Metabolic heat rate was measured with a MC-DSC calorimeter. While some sampling periods showed significant responses to some treatments, the study as a whole suggests the addition of calcium and/or nitrogen had minimal effects on photosynthesis or metabolism.Item An Ecological Perspective of the Energy Basis of Sustainable Bolivian Natural Resources: Forests and Natural Gas(2008-04-29) Izursa, Jose-Luis; Tilley, David R.; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Bolivia, traditionally known for being a country rich in natural resources, has suffered from a constant exploitation of its natural resources benefiting only small groups in and outside the country. The devastation of natural resources that occurred for many years was of concern to the latest government, rural communities and indigenous groups. As a result, Bolivia has a more sustainability-oriented forest law that has a strong orientation towards the utilization of natural resources at a national level and encompasses a fast-growing forestry industry than in previous years. In this dissertation, the wealth of Bolivia's national system was evaluated using solar emergy. Emergy (spelled with "m") is the sum of all energy of one form needed to develop a flow of energy of another form, over a period of time. The basic idea is that solar energy is our ultimate energy source and by expressing the value of products in solar emergy units, it becomes possible to compare different kinds of energy, allowing to express the value for the natural resources in Emergy Dollars. It was found out that Bolivia relies heavily in its natural resources and that its emergy exchange ratio with its international trading partners changed from 12.2 to 1 in 2001 to 6.2 to 1 in 2005. This means that Bolivia went from export 12.2 emdollars of goods for each $1 it received in 2001 to export 6.2 emdollars of products for each $1 it received in 2005. The study also showed that under forest certification practices less emergy is removed from forests (1.49E+19 sej/yr) compared to the amount of emergy removed (2.36E+19 sej/yr) under traditional uncertified practices, reflecting that forest ecology does better under certification. The "Ecologically-based Development for the Bolivian Industrial Forestry System" (DEBBIF) simulation model constructed during this study, compared four different scenarios: the Reference Scenario, the Increased Export Scenario, the Increased Domestic Use Scenario and the National Industrialization Scenario. Using two different levels of increment for each scenario, the outcomes of six variables were analyzed: soil, wood, natural gas, assets, money and debt. It was found that if the country doubles its use of natural resources to generate finished products, this will build more assets for Bolivia, and represent more income for the country and a better rate of emergy per person.Item Chemotherapeutic Treatment Options to Manage Xylella fastidiosa in Shade Trees(2005-12-13) DeStefano, Darren Albert; Sullivan, Joseph; Plant Science and Landscape Architecture (PSLA); Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Xylella fastidiosa is a fastidious, xylem-limited, broad spectrum, bacterial plant pathogen native to the Americas, causing substantial economic losses to the viticulture, citrus, and shade tree industries. In shade trees the disease is manifested as a chronic late season leaf scorch largely confined to urban areas of southeastern North America. Proposed treatments include antibiotics and growth regulators. Recently paclobutrazol, a diastereomeric triazole with fungistatic and growth regulation properties has been associated with symptom remission. Investigation into direct interaction of paclobutrazol with X. fastidiosa show no significant reduction in growth at the manufacturers recommended dosage of 20 µg ml-1; however significant reductions in growth were observed at a dosage of 200 µg ml-1. Therefore high levels of paclobutrazol may have a direct effect on X. fastidiosa while other plant physiological effects induced by paclobutrazol merit investigation for association in symptom mitigation of X. fastidiosa.Item MEASURING AND MAPPING FOREST WILDLIFE HABITAT CHARACTERISTICS USING LIDAR REMOTE SENSING AND MULTI-SENSOR FUSION(2005-12-05) Hyde, Peter; Dubayah, Ralph O.; Geography; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Managing forests for multiple, often competing uses is challenging; managing Sierra National Forest's fire regime and California spotted owl habitat is difficult and compounded by lack of information about habitat quality. Consistent and accurate measurements of forest structure will reduce uncertainties regarding the amount of habitat reduction or alteration that spotted owls can tolerate. Current methods of measuring spotted owl habitat are mostly field-based and emphasize the important of canopy cover. However, this is more because of convenience than because canopy cover is a definitive predictor of owl presence or fecundity. Canopy cover is consistently and accurately measured in the field using a moosehorn densitometer; comparable measurements can be made using airphoto interpretation or from examining satellite imagery, but the results are not consistent. LiDAR remote sensing can produce consistent and accurate measurements of canopy cover, as well as other aspects of forest structure (such as canopy height and biomass) that are known or thought to be at least as predictive as canopy cover. Moreover, LiDAR can be used to produce maps of forest structure rather than the point samples available from field measurements. However, LiDAR data sets are expensive and not available everywhere. Combining LiDAR with other, remote sensing data sets with less expensive, wall-to-wall coverage will result in broader scale maps of forest structure than have heretofore been possible; these maps can then be used to analyze spotted owl habitat. My work consists of three parts: comparison of LiDAR estimates of forest structure with field measurements, statistical fusion of LiDAR and other remote sensing data sets to produce broad scale maps of forest structure, and analysis of California spotted owl presence and fecundity as a function of LiDAR-derived canopy structure. I found that LiDAR was able to replicate field measurements accurately. Additionally, I was able to statistically combine LiDAR with passive optical and RaDAR (SAR backscatter and InSAR range) data to produce broad scale maps of forest structure that are consistent and accurate relative to field data and LiDAR data alone. Finally, I was able to demonstrate that these forest structural attributes predict spotted owl presence and absence as well as productivity.Item Utilizing Hybrid Poplar Trees to Phytoremediate Soils with Excess Phosphorus(2005-09-01) Neal, Amy; McIntosh, Marla S; Plant Science and Landscape Architecture (PSLA); Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Phytoremediation, using plants to remove soil pollutants, has been suggested as a method to remove P from over-enriched soils. This research investigated the potential of utilizing hybrid poplar trees to remove excess P from soils associated with long-term poultry manure application. Hybrid poplar clones were planted in Snow Hill, MD, on three fields differing in previous poultry manure applications with Mehlich-3 soil-test P levels of 261, 478, and 982 mg P kg-1. During this two year study, soil P decreased on fields planted with hybrid poplar; the magnitude of the reduction was positively associated with initial soil-test P. Plant tissue P concentrations increased with soil P concentration. However, factors other than plant uptake were hypothesized to contribute to the soil-test P reductions. Results suggest that hybrid poplars have the potential to phytoremediate soils with excess P but that soil chemistry also impacts the fate of available P in the soil.Item Assessing evapotranspiration rates of a Mid-Atlantic red maple riparian wetland using sap flow sensors.(2005-04-13) Renz, Jennifer Theresa; Momen, Bahram; Plant Science and Landscape Architecture (PSLA); Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Riparian forests are unique due to increased exposure of trees to winds and radiation and the subsequent effects on the quality and quantity of water discharge from the system. Since "edge effects" can enhance evapotranspiration (ET) of exposed trees, ET rates of a first-order red maple riparian wetland were assessed with thermal dissipation probes during the 2002 growing season to address: a) if edge trees transpire more water daily than interior trees, b) correlations among sap flow rates and energy balance-derived estimates, c) variations in ecosystem ET estimates based on 6 scaling variables, and d) diurnal correlations between maximum sap flow rates and streamflow losses. Results from this study indicate that: a) edge trees transpire more water daily than interior trees during early summer, b) choice of scaling variable affects estimation of ecosystem ET rates, and c) maximum sap flow rates correlate with streamflow losses diurnally under specific environmental conditions.Item The Establishment and Persistence of American Ginseng (Panax quinquefolius L.) in Maryland Forests.(2005-05-26) Slak, David; McIntosh, Marla; Plant Science and Landscape Architecture (PSLA); Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)American ginseng (Panax quinquefolius L.) is a profitable non-timber forest product with the potential of improving the sustainability of Maryland forests. In order to determine factors affecting Maryland ginseng production, ginseng seeds and roots were planted in forests in Eastern, Central, and Western Maryland in plots amended with no treatment, lime, or gypsum. The response variables measured included soil nutrients and ginseng persisence and establishment. In general, soil lime treatments improved establishment at the Eastern but not the Central or Western sites. The gypsum soil treatments did not significantly affect populations. Establishment of American ginseng grown from seed ranked by site was Western>Central>Eastern. Conversely, root establishment was best at the Eastern site. Across sites, soil pH, Ca, Mg, and K were positively correlated with establishment and persistence. Thus, American ginseng was grown throughout Maryland and ginseng production was enhanced by lime addition at the Eastern site.Item INTEGRATED ECOLOGICAL ECONOMIC MODELING OF ECOSYSTEM SERVICES FROM THE BRAZILIAN AMAZON RAINFOREST(2004-10-26) Portela, Rosimeiry G.; Costanza, Robert; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation links the natural and social sciences, using modeling techniques to enhance understanding of the functioning of a complex ecosystem and its relevance to humans. For this purpose, I developed a Regional Unified Metatomodel of the Brazilian Amazon (RUMBA) to simulate the Amazon forest provision of ecosystem goods and services and their contribution to human economy and welfare. The model was also used to simulate the potential effect of an incentive to reduce deforestation in return for a payment for avoided releases of carbon into the atmosphere. Simulation was done from 1975 to 2100, with calibration performed for the first 25 years, and for four scenarios: a baseline scenario, based on historical trends, and four alternative scenarios based on different assumptions and policy choices. The baseline scenario shows deforestation proceeding at high rates, leading to decreasing provision of forest goods and services and increasing economic growth. The growth of GRP per capita, on the other hand, remains much smaller than that of GRP. Regional welfare decreases significantly over the simulated period. The overall monetary contribution of ecosystem goods and services to the regional economy is estimated as 5 times the GRP in year 2100. Scenarios of increased investment in development yielded higher economic growth accompanied by lower levels of welfare, while opposite trends were found for scenarios of higher investment in human, knowledge and natural capital. Finally, results also show that in order for a monetary compensation to represent a significant incentive to land owners to reduce deforestation, higher prices for avoided carbon emissions would have to be set than current prices of the emerging carbon market. Main research findings are that increasing land use change in the Brazilian Amazon incurs significant losses of ecosystem services without this being adequately offset by increasing monetary income or welfare of people. This reseach has also found that in the absence of significant incentives from global beneficiaries for any one ecosystem service, or a combination of incentives addressing several types of ecosystem services, rational land uses at the local level lead to sub-optimal provision of these services from the global perspective.