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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

An Inventory and Recommendations for the Management of High Priority Invasive Alien Plants in Point Pelee National Park

Mosher, Andrea 22 August 2012 (has links)
Point Pelee National Park in Ontario, Canada has been affected by a long history of human activity. This activity has encouraged the establishment of approximately 276 exotic invasive plant species. These plants decrease biodiversity and effective function of ecosystems within the Park. A 5 Year Exotic Plant Species Management Plan for the Park was written in 1990. Since that time inventories have been done on some of the species but a monitoring of all the high priority exotic invasive plants has not. As part of this study an inventory of the high priority exotic invasive plants and their spatial extent in the Park, was created. From May to September, 2011 a comprehensive inventory took place within a 5.5km stretch in the terrestrial area at the southern end of the Park. Systematic belt transects were performed, on foot, from west to east at 100 m intervals. Within the quadrats percent cover of each plant species was determined. The data collected in the field were compiled using geographic information systems (GIS), resulting in maps of the extent of the most abundant species studied. Analysis as part of this study included using the data to determine which plants and areas are higher priorities for management within the Park. Quadrats were analysed for diversity using the Simpson Index and, since the data was non-parametric, comparisons were made across diversity and native richness using the Kruskal Wallis test. Alliaria officinalis is the only non-native species that is widespread within the study area. Other non-native species with a high potential for invasiveness were observed but only consisted of a few individuals along roads and paths. Some non-native species were present along or near roads and paths in denser patches (17-100% plot coverage). Recommendations include removal of some non-native species deemed to be a potential threat to native richness and diversity, followed by re-vegetation with native species, and continued monitoring. Future restoration efforts are best directed at the area around DeLaurier, along west beach and at the Tip. These areas have the lowest diversity and native richness and therefore need the most improvement.
2

An Inventory and Recommendations for the Management of High Priority Invasive Alien Plants in Point Pelee National Park

Mosher, Andrea 22 August 2012 (has links)
Point Pelee National Park in Ontario, Canada has been affected by a long history of human activity. This activity has encouraged the establishment of approximately 276 exotic invasive plant species. These plants decrease biodiversity and effective function of ecosystems within the Park. A 5 Year Exotic Plant Species Management Plan for the Park was written in 1990. Since that time inventories have been done on some of the species but a monitoring of all the high priority exotic invasive plants has not. As part of this study an inventory of the high priority exotic invasive plants and their spatial extent in the Park, was created. From May to September, 2011 a comprehensive inventory took place within a 5.5km stretch in the terrestrial area at the southern end of the Park. Systematic belt transects were performed, on foot, from west to east at 100 m intervals. Within the quadrats percent cover of each plant species was determined. The data collected in the field were compiled using geographic information systems (GIS), resulting in maps of the extent of the most abundant species studied. Analysis as part of this study included using the data to determine which plants and areas are higher priorities for management within the Park. Quadrats were analysed for diversity using the Simpson Index and, since the data was non-parametric, comparisons were made across diversity and native richness using the Kruskal Wallis test. Alliaria officinalis is the only non-native species that is widespread within the study area. Other non-native species with a high potential for invasiveness were observed but only consisted of a few individuals along roads and paths. Some non-native species were present along or near roads and paths in denser patches (17-100% plot coverage). Recommendations include removal of some non-native species deemed to be a potential threat to native richness and diversity, followed by re-vegetation with native species, and continued monitoring. Future restoration efforts are best directed at the area around DeLaurier, along west beach and at the Tip. These areas have the lowest diversity and native richness and therefore need the most improvement.
3

The Effect of Subsurface Hydrology on DDT Degradation in Soils at Point Pelee National Park, Ontario, Canada

Marenco , Nadia 09 1900 (has links)
<p> Systematic soil sampling and analyses provided DDT, DDE and DDD, organic and mineral matter concentrations, as well as various soil physical and hydraulic properties from three study sites at Point Pelee National Park. A soil's physical properties, soil and water management practices, and DDT application history, can affect DDT degradation and change the relative amount of its metabolites. DDD is the principal product of the dechlorination of DDT in high moisture content, reducing anaerobic soil environments. The main degradation product in soils under aerobic conditions is DDE. %DDT, %DDE and %DDD abundances used in conjunction with soil environment characterization data, can be used to indicate not only whether DDT is degrading, but what environmental factors are controlling its degradation. At the Park, DDT is primarily lost from the soil by microbial degradation to DDE and DDD. %DDT, %DDE and %DDD ratios from each study site indicated that wetter more organic-rich soil environments degraded DDT to its metabolites at a faster rate than drier less organicrich soils. Moreover, historical water level data was used to illustrate that this wetter study site was flooded for part of the year when adjacent marsh water levels were high. These conditions resulted in the accumulation of organic matter over time and the creation of alternating anaerobic/aerobic conditions in the soils resulting in an increased rate of degradation of DDT in these areas. Based on the relative %DDT in the soils at each study site, relative half-life estimates for the first order decay of DDT to its metabolites DDE and DDD were calculated. Half-life estimates for DDT at the wettest and most organic-rich study site range from 6 to 8 years; significantly lower than the two other study sites, which range from 15 to 30 years and are on the high end of the range reported in the literature.</p> / Thesis / Master of Science (MSc)
4

A Field and Modeling Study of DDT in Soil and Groundwater Following In-Situ Soil Remediation

Mironov, Marina 09 1900 (has links)
<p>The shallow soils of a former orchard area in Point Pelee National Park, near Leamington, Ontario, Canada have elevated concentrations of chlorinated pesticides above the regulatory limits. Previous studies in this area have shown that the DDT, DOE and ODD are highly persistent with an estimated half-life of DDT in the range of 15-30 years. In 2002 a pilot-scale field remediation experiment involving the application of cyclodextrin was conducted. This experiment resulted in substantial decrease of DDT, DDE and DDD concentrations in the upper soil layer within the remediation grid. Soil samples were collected within the treatment plots a year after the cyclodextrin application was completed to assess any further changes in concentrations of DDT, DDE and DDD. Groundwater samples were collected in the vicinity of the soil remediation grid which provided DDT, DDE and DDD concentrations in groundwater to assess the vertical mobilization of the compounds. Mass balance of the "soil - groundwater" system was calculated in order to estimate the degradation rate of DDT within the remediation zone. The 2-D unsaturated/saturated flow and solute transport numerical model "HYDRUS 2-D" was used to gain a better estimation of DDT, DDE and DDD mass and distribution in groundwater. The effectiveness of cyclodextrin application for remediation of DDT contaminated soils was assessed. After remediation treatments had stopped, there was no indication of further degradation of DDT and its metabolites in the upper layer of soil. The groundwater concentration of DDT, DDE and DDD near the remediation grid was 10-100 times higher than background value. This increase in groundwater concentration is a direct indication of DDT, DDE and DDD mobilization by cyclodextrin. The estimates of total mass of DDT in groundwater are less than 1% of mass leached from the soil. It was concluded that the application of cyclodextrin promoted enhanced co-metabolic biodegradation of DDT and it metabolites DDE and DDD. The estimated half-life for the displaced DDT was less than 2 months. This work demonstrates that cyclodextrin can be a highly effective agent for remediation of DDT contaminated soils.<p> / Thesis / Master of Science (MSc)

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