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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

Spatial Patterns of Tree Invasion in an Old Field: Implications for Restoration

Buschert, Karen Elizabeth January 2008 (has links)
In north-eastern North America, abandoned agricultural fields typically revert to forest after many decades of spontaneous succession. This process can be influenced in part by nearby available propagule sources and their natural patterns of dispersal. Ecological restoration encompasses understanding this natural process and how it may influence active or passive restoration efforts. This study attempts to determine the spatial and temporal patterns of establishing trees arising in an old field at 10 years post-cultivation and the implications of this process on restoration at rare and other similar sites. The 0.8 ha field is situated at rare, an ecological reserve in Cambridge, Ontario and is bordered by forest or hedgerow on all sides. Using Environmental Monitoring and Assessment Network (EMAN) protocols, vegetation sampling was completed in the field and adjacent forest and hedgerow. A complete tree inventory was undertaken in the field, followed by a sampling of potential seed sources in the forest and hedgerow. ESRI ArcMap, a Geographic Information System (GIS) was utilized for both spatial representation and spatial analysis. Research revealed that the application of geostatistics to ecological data here and elsewhere in the literature has some specific challenges which need to be overcome for analysis of spatial data. Currently, the old field shows early signs of woody plant invasion from the nearby forest. Both trees and shrubs have become established, though not yet dominant. The primary dispersal of these species follows spatial patterns based on method of dispersal (wind, nut, fruit and clonal) and there is a higher degree of clustering of all species closer to the forest edge. Invasive species such as Rhamnus cathartica and Rhamnus frangula have become established in the old field and may influence successional patterns. Implications for restoration include the creation of goals and objectives which incorporate these natural processes into a future management plan. Specific recommendations include: 1) Develop a management strategy for invasive species such as Rhamnus spp. which can detrimentally affect restoration goals; 2) Continue to monitor EMAN plots for the production of time-series data on the same site; 3) Identify sites with good regeneration potential based on spatial patterns identified in this research and collect additional information such as soil conditions, canopy cover, etc.; 4) Extend the current GIS database created for this thesis to become an inventory of natural and cultural features for the reserve. Advanced spatial analysis required a more extensive data set and/or custom programming.
2

Spatial Patterns of Tree Invasion in an Old Field: Implications for Restoration

Buschert, Karen Elizabeth January 2008 (has links)
In north-eastern North America, abandoned agricultural fields typically revert to forest after many decades of spontaneous succession. This process can be influenced in part by nearby available propagule sources and their natural patterns of dispersal. Ecological restoration encompasses understanding this natural process and how it may influence active or passive restoration efforts. This study attempts to determine the spatial and temporal patterns of establishing trees arising in an old field at 10 years post-cultivation and the implications of this process on restoration at rare and other similar sites. The 0.8 ha field is situated at rare, an ecological reserve in Cambridge, Ontario and is bordered by forest or hedgerow on all sides. Using Environmental Monitoring and Assessment Network (EMAN) protocols, vegetation sampling was completed in the field and adjacent forest and hedgerow. A complete tree inventory was undertaken in the field, followed by a sampling of potential seed sources in the forest and hedgerow. ESRI ArcMap, a Geographic Information System (GIS) was utilized for both spatial representation and spatial analysis. Research revealed that the application of geostatistics to ecological data here and elsewhere in the literature has some specific challenges which need to be overcome for analysis of spatial data. Currently, the old field shows early signs of woody plant invasion from the nearby forest. Both trees and shrubs have become established, though not yet dominant. The primary dispersal of these species follows spatial patterns based on method of dispersal (wind, nut, fruit and clonal) and there is a higher degree of clustering of all species closer to the forest edge. Invasive species such as Rhamnus cathartica and Rhamnus frangula have become established in the old field and may influence successional patterns. Implications for restoration include the creation of goals and objectives which incorporate these natural processes into a future management plan. Specific recommendations include: 1) Develop a management strategy for invasive species such as Rhamnus spp. which can detrimentally affect restoration goals; 2) Continue to monitor EMAN plots for the production of time-series data on the same site; 3) Identify sites with good regeneration potential based on spatial patterns identified in this research and collect additional information such as soil conditions, canopy cover, etc.; 4) Extend the current GIS database created for this thesis to become an inventory of natural and cultural features for the reserve. Advanced spatial analysis required a more extensive data set and/or custom programming.
3

Optimizing Native and Landscape Plant Establishment Under Marginal Soil and Water conditions in Southwestern Deserts

Gerhart, Vanda Jane January 2005 (has links)
Two aspects of salinity in arid land were investigated as part of the present dissertation: the first was the potential re-use of industrially generated brine for irrigating landscape plants, and the second was the ecological restoration of saline farmland. The following is a summary of the most important points. With water conservation efforts accelerating in arid environments, industrial wastewater is considered a candidate for re-use. We investigated the use of high EC (electrical conductivity) cooling-tower water to irrigate nine common landscape plants in an urban environment. Each plant (replicated in a block design) was irrigated according to water demand determined by the soil moisture deficit, with one of three water treatments: blowdown water (3.65 dS m⁻¹), well water (0.52 dS m⁻¹) and a 1:1 blend (2.09 dS m⁻¹). Results indicate the salinity of the irrigation water did not have a significant effect (P>0.05) on growth or water use but, soil salinities were higher in basins irrigated with blowdown water compared to those irrigated with well water. The overall feasibility of reusing industrial brines to irrigate urban landscapes is discussed in light of the results. Restoring abandoned arid farmland can be challenging because topographic, geomorphic and hydrologic features have been degraded and cannot support a diverse native plant community. Typical amelioration practices depend upon good quality water to restore the soil’s physiochemical properties, however the long-term availability of any water is rare. A mitigation banking project to return 432 hectares of farmland to an open-space designation involved the collaboration of scientists, landscape architects and engineers to achieve five main goals: water management, erosion control, decreasing soil salinity, and increasing species diversity and vegetation cover. Two strategies evolved in the planning process that work in tandem to achieve these goals: a water management system that redirects storm water and run-off to discrete areas of the site for subsurface storage as plant-available water, and the introduction of a diverse mix of native plants. Field trials tested the strategies and also investigated different soil surface treatments, seeding methods and irrigation regimes against the germination and establishment of a customized native seed mix. Results from vegetation data indicate a combination of soil ripping and imprinting leads to the highest germination and establishment rates and drip irrigation helped establish transplanted seedlings. The project was designed so the longterm outcome does not depend on continual inputs and maintenance.
4

Conservation and ecological restoration of Rocky Mountain subalpine meadows: vegetation responses to tree encroachment

Shaw, Adrienne Kara 20 April 2009 (has links)
Over the past century tree encroachment has occurred in North American subalpine meadows. Causes of tree establishment have been related to climate influences and exclusion of fire, but very few studies have looked at the consequence of tree encroachment on meadow vegetation. Within the southern Canadian Rocky Mountains, Waterton Lakes National Park and Castle Special Management Area, 14 meadows were randomly selected at wet and dry sites. Nonmetric multidimensional scaling showed that species composition changed during the transition of open meadow to forest for both wet and dry habitats. There were no significant differences in these two management areas in terms of conifer encroachment and the effects on meadow species. Results of this study show that conifer encroachment has increased over the last century with the consequences of loss in meadow species through a decrease in abundance, richness and diversity. Wet sites were significantly more sensitive to conifer encroachment than dry sites. The greatest inhibitory effects of trees on meadow vegetation within the ecotone occurred when trees were 54-72 years old for wet sites and 77-112 years old for dry sites. Ecological restoration of these meadows is important for ongoing habitat conservation, maintaining species and landscape diversity and ecosystem resilience.
5

The resurrection and the restoration of nature : towards a theological framework for Christian environmental action through ecological restoration

Artinian-Kaiser, Rebecca G. January 2015 (has links)
The context in which we find ourselves at the beginning of the twenty-first century is one of acute environmental degradation. In this thesis, I examine how Christians may respond to the realities of degradation through ecological restoration, an environmental practice aimed at assisting the recovery of ecosystems that have been degraded, damaged, or destroyed, and do so in ways that reflect the core belief in the redemptive purposes of God in Christ for creation. The intention, therefore, is to construct a theological framework for ethical responses to degradation through restoration. I begin by examining ecological restoration as a contested scientific and cultural practice, exploring the questions it raises on the nature of human life, the natural world, and moral action, and evaluating the role of history in shaping moral responses to degradation through restoration. To develop a theological framework for restoration, I engage the work of Christian ethicist Oliver O'Donovan, particularly his text on the foundations of Christian ethics: Resurrection and Moral Order. I ground this framework in his arguments for the resurrection (with its dual movements of restoration and transformation) as the starting point for moral action, for the work of the Holy Spirit who makes God’s redemption a reality that shapes moral action, and for love as the shape of moral action. I draw out the significance for restoration of his moral realist approach, examining the created order and articulating a theological anthropology, and I show how the resurrection of Christ provides a guide for restorative action that both affirms the created order and yet remains attentive and open to its, and our, transformation. Finally, through an examination of love as perceptive and responsive to the natural world, I articulate a vision for restorative action that is oriented toward upholding and preserving the value of the natural world, and attentively and creatively responding to it in ways that bring forth its value so that it may be seen for what it is: the beloved world that God has affirmed and redeemed in the resurrection and which awaits its fulfilment.
6

Split-flow Stormwater Management Strategy Design Feasibility and Cost Comparison

Echols, Stuart Patton 10 December 2002 (has links)
This dissertation develops a new distributed split-flow stormwater management strategy and compares its site design feasibility and construction cost to existing stormwater management methods. The purpose of the split-flow strategy is to manage stormwater by preserving predevelopment flows in terms of rate, quality, frequency, duration and volume. This strategy emulates the predevelopment hydrology: it retains and infiltrates additional runoff volume created by development by using bioretention and paired weirs as proportional flow splitters connected to small infiltration facilities distributed throughout a site. Results show that 1) the distributed split-flow stormwater management strategy can provide a higher level of environmental protection at comparable construction cost to existing detention-based methods, 2) split-flow systems are less expensive to construct than current truncated hydrograph-based bioretention and infiltration systems and 3) non-point source water pollution-reduction objectives, currently achieved with either detention with first flush or comparable bioretention and infiltration systems, could be achieved in a more cost-effective manner using distributed split-flow stormwater management strategy. / Ph. D.
7

Assessing Progress of Urban Ecological Restoration Using Transplants

Ihrig, Megan Esther January 2011 (has links)
Forests are the dominant terrestrial ecosystem in Ontario and were once widespread throughout much of eastern North America; in southern Ontario, forest cover has declined from 90% to approximately 17% in the past 200 years. Conversion of the surrounding landscape to urban and agricultural land uses creates edge effects which increase the impact of forest cover loss and threaten ecological integrity. Other impacts on forest ecological integrity include incompatible human activities, a generally inhospitable landscape matrix, and microenvironment changes, including those from chemical pollution and heat island effects. Coupled with direct degradation from human activities like free-riding, the altered forest microenvironment can facilitate increased invasion by opportunistic and competitive plant species, e.g. Alliaria petiolata (Brassicaceae). This tends to be worse in urban areas because of greater visitation that creates soil compaction, trampling, and more vectors to introduce the seeds of invasive species. Active management is often necessary in areas which have been degraded. Ecological restoration represents an important active management tool for urban forest protected area managers. The ecological restoration of the forest understory in altered and threatened habitats represents an important aspect of forest restoration. For this study, I tested the effectiveness of an ecological restoration using a multi-species assemblage approach with three native understory species to restore the herbaceous layer in Natchez Hills, an Environmentally Sensitive Policy Area in Kitchener, Ontario. The ecological restoration site was degraded and this reduced native plant species in the forest understory. The species selected, Caulophyllum giganteum (Farwell) Loconte & W.H. Blackwell (Berberidaceae), Podophyllum peltatum Linnaeus (Berberidaceae) and Maianthemum racemosum subsp. racemosum (Linneaus) Link (Asparagaceae), are widespread throughout eastern North America, and were selected for use in this study because of their persistence and relative abundance in Natchez Hills ESPA. Adult transplants were planted into 2 metre by 2 metre quadrats in different densities and shoot populations were monitored for two field seasons to determine if density played a role in early ecological restoration success. The methodology I designed for the ecological restoration was as practical as possible, given the real world financial and logistical constraints faced by many urban forest managers. Statistical analysis using repeated measures multivariate analysis of variance showed aerial shoot density did not have a significant effect on early restoration success rates (p > 0.05). However, there was a significant increase in restored species. Caulophyllum giganteum and Podophyllum peltatum shoot populations increased by over 97% at the ecological restoration site one year after transplanting. Maianthemum racemosum subsp. racemosum shoot populations increased by 51% at the site. For comparison, another study in the same forest reported early ecological restoration rates of 92% to 100% for herbaceous understory species, including C. giganteum and P. peltatum. Other North American studies using transplanted perennial herbaceous material reported average survival rates of 16.6% two years after planting (varying from 1.25% to 51.4% using eight herbaceous species in the Boston area), to 91% one year after restoration (varying from 42.1% to 100% using 19 herbaceous species of the deciduous forest in the Midwest). In instances where protected areas are degraded, active management and ecological restoration are often necessary tools. This ecological restoration demonstrated that the native herbaceous species used in this study are suitable for use in early ecological restorations in maple beech upland forests in the City of Kitchener. Using a practical and cost-effective methodology this ecological restoration experiment showed that it is possible to implement urban restoration of the forest understory in degraded areas, and to achieve success in early ecological restoration using native herbaceous forest understory species.
8

Assessing Progress of Urban Ecological Restoration Using Transplants

Ihrig, Megan Esther January 2011 (has links)
Forests are the dominant terrestrial ecosystem in Ontario and were once widespread throughout much of eastern North America; in southern Ontario, forest cover has declined from 90% to approximately 17% in the past 200 years. Conversion of the surrounding landscape to urban and agricultural land uses creates edge effects which increase the impact of forest cover loss and threaten ecological integrity. Other impacts on forest ecological integrity include incompatible human activities, a generally inhospitable landscape matrix, and microenvironment changes, including those from chemical pollution and heat island effects. Coupled with direct degradation from human activities like free-riding, the altered forest microenvironment can facilitate increased invasion by opportunistic and competitive plant species, e.g. Alliaria petiolata (Brassicaceae). This tends to be worse in urban areas because of greater visitation that creates soil compaction, trampling, and more vectors to introduce the seeds of invasive species. Active management is often necessary in areas which have been degraded. Ecological restoration represents an important active management tool for urban forest protected area managers. The ecological restoration of the forest understory in altered and threatened habitats represents an important aspect of forest restoration. For this study, I tested the effectiveness of an ecological restoration using a multi-species assemblage approach with three native understory species to restore the herbaceous layer in Natchez Hills, an Environmentally Sensitive Policy Area in Kitchener, Ontario. The ecological restoration site was degraded and this reduced native plant species in the forest understory. The species selected, Caulophyllum giganteum (Farwell) Loconte & W.H. Blackwell (Berberidaceae), Podophyllum peltatum Linnaeus (Berberidaceae) and Maianthemum racemosum subsp. racemosum (Linneaus) Link (Asparagaceae), are widespread throughout eastern North America, and were selected for use in this study because of their persistence and relative abundance in Natchez Hills ESPA. Adult transplants were planted into 2 metre by 2 metre quadrats in different densities and shoot populations were monitored for two field seasons to determine if density played a role in early ecological restoration success. The methodology I designed for the ecological restoration was as practical as possible, given the real world financial and logistical constraints faced by many urban forest managers. Statistical analysis using repeated measures multivariate analysis of variance showed aerial shoot density did not have a significant effect on early restoration success rates (p > 0.05). However, there was a significant increase in restored species. Caulophyllum giganteum and Podophyllum peltatum shoot populations increased by over 97% at the ecological restoration site one year after transplanting. Maianthemum racemosum subsp. racemosum shoot populations increased by 51% at the site. For comparison, another study in the same forest reported early ecological restoration rates of 92% to 100% for herbaceous understory species, including C. giganteum and P. peltatum. Other North American studies using transplanted perennial herbaceous material reported average survival rates of 16.6% two years after planting (varying from 1.25% to 51.4% using eight herbaceous species in the Boston area), to 91% one year after restoration (varying from 42.1% to 100% using 19 herbaceous species of the deciduous forest in the Midwest). In instances where protected areas are degraded, active management and ecological restoration are often necessary tools. This ecological restoration demonstrated that the native herbaceous species used in this study are suitable for use in early ecological restorations in maple beech upland forests in the City of Kitchener. Using a practical and cost-effective methodology this ecological restoration experiment showed that it is possible to implement urban restoration of the forest understory in degraded areas, and to achieve success in early ecological restoration using native herbaceous forest understory species.
9

Sustainable Foodscapes: Obtaining Food within Resilient Communities

King, Meaghan January 2009 (has links)
This thesis examines the feasibility of fostering “sustainable foodscapes” in urban communities. A review of the literature on the topics of sustainability, resilience, sustainable food security, and healthy communities is used to determine to the definition of “sustainable foodscapes.” This thesis uses a framework of socio-ecological restoration to consider how communities might adopt sustainable foodscapes. A case study is conducted in the city of Waterloo, Ontario to test the criteria of sustainable foodscapes and explore some of the practical opportunities and barriers to developing sustainable foodscapes in an urban community. The methods for the case study include semi-structured interviews. Interview results indicate that a variety of sustainable foodscapes such as community gardening, individual gardening, and foraging are used in Waterloo already, and survey results suggest that various members of the community are open to the adoption of these foodscapes. The case study results reveal that diverse community members view sustainable foodscapes as an important contribution to community health, less for the purpose of ecological sustainability than for their usefulness as a way of promoting community interaction, social learning, and fostering a sense of place. Ways to conduct a socio-ecological restoration for sustainable foodscapes in Waterloo could include increasing areas for the purposes of foraging to occur in an ecologically benign manner, such as on marginal or private land; creating municipal policies and Official Plans that provide support for community gardens, and fostering more accepting attitudes towards sustainable foodscapes by providing increased opportunities for education and participation among community members.
10

Sustainable Foodscapes: Obtaining Food within Resilient Communities

King, Meaghan January 2009 (has links)
This thesis examines the feasibility of fostering “sustainable foodscapes” in urban communities. A review of the literature on the topics of sustainability, resilience, sustainable food security, and healthy communities is used to determine to the definition of “sustainable foodscapes.” This thesis uses a framework of socio-ecological restoration to consider how communities might adopt sustainable foodscapes. A case study is conducted in the city of Waterloo, Ontario to test the criteria of sustainable foodscapes and explore some of the practical opportunities and barriers to developing sustainable foodscapes in an urban community. The methods for the case study include semi-structured interviews. Interview results indicate that a variety of sustainable foodscapes such as community gardening, individual gardening, and foraging are used in Waterloo already, and survey results suggest that various members of the community are open to the adoption of these foodscapes. The case study results reveal that diverse community members view sustainable foodscapes as an important contribution to community health, less for the purpose of ecological sustainability than for their usefulness as a way of promoting community interaction, social learning, and fostering a sense of place. Ways to conduct a socio-ecological restoration for sustainable foodscapes in Waterloo could include increasing areas for the purposes of foraging to occur in an ecologically benign manner, such as on marginal or private land; creating municipal policies and Official Plans that provide support for community gardens, and fostering more accepting attitudes towards sustainable foodscapes by providing increased opportunities for education and participation among community members.

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