• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 94
  • 9
  • 4
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 123
  • 123
  • 56
  • 25
  • 25
  • 24
  • 15
  • 13
  • 12
  • 11
  • 10
  • 9
  • 9
  • 9
  • 9
  • 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.
51

Remote Sensing of Urbanization and Environmental Impacts

Haas, Jan January 2016 (has links)
This thesis aims to establish analytical frameworks to map urban growth patterns with spaceborne remote sensing data and to evaluate environmental impacts through Landscape Metrics and Ecosystem Services. Urbanization patterns at regional scale were evaluated in China's largest urban agglomerations and at metropolitan scale in Shanghai, Stockholm and Beijing using medium resolution optical satellite data. High-resolution data was used to investigate changes in Shanghai’s urban core. The images were co-registered and mosaicked. Tasseled Cap transformations and texture features were used to increase class separabilities prior to pixel-based Random Forest and SVM classifications. Urban land cover in Shanghai and Beijing were derived through object-based SVM classification in KTH-SEG. After post-classification refinements, urbanization indices, Ecosystem Services and Landscape Metrics were used to quantify and characterize environmental impact. Urban growth was observed in all studies. China's urban agglomerations showed most prominent urbanization trends. Stockholm’s urban extent increased only little with minor environmental implications. On a regional/metropolitan scale, urban expansion progressed predominately at the expense of agriculture. Investigating urbanization patterns at higher detail revealed trends that counteracted negative urbanization effects in Shanghai's core and Beijing's urban-rural fringe. Beijing's growth resulted in Ecosystem Services losses through landscape structural changes, i.e. service area decreases, edge contamination or fragmentation. Methodological frameworks to characterize urbanization trends at different scales based on remotely sensed data were developed. For detailed urban analyses high-resolution data are recommended whereas medium-resolution data at metropolitan/regional scales is suggested. The Ecosystem Service concept was extended with Landscape Metrics to create a more differentiated picture of urbanization effects.​ / <p>QC 20160205</p>
52

Missing "Links": Investigating the Age and Gender Dimensions of Development, Conservation, and Environmental Change in a Southern Zambian Frontier

Harnish, Allison 01 January 2013 (has links)
This dissertation focuses on the lived, material realities of rural women, men, girls, and boys struggling to make a living in the context of changing national development priorities and changing environmental conditions in Southern Province, Zambia. Over the last 20 years, Gwembe Tonga migrants living in the frontier farming area of Kulaale have witnessed significant declines in non-cultivated “bush” resources due to the conversion of forest and grassland to agricultural uses. This dissertation seeks to understand how women, men, boys, and girls differently experience these declines according to local gender- and age-based divisions of subsistence labor. Drawing on a variety of theoretical lenses—including Feminist Geography, Feminist Political Ecology, African Feminisms, the Anthropology of Childhood, and the Anthropology of the State—and utilizing a unique blend of qualitative/ethnographic and quantitative/geospatial research methods, this study finds that the “extractive workloads” (the average annual distance traveled for the collection of key bush resources) associated with women, men, girls, and boys are both unequal and contrary to recent speculations about the distinctive vulnerability of adult women to environmental change. The unequal labor burdens associated with the extraction of bush resources in this changing frontier landscape are but one of several missing “links” that this dissertation identifies within current theorizing about the gendered dimensions of environmental change. Other “links” include the social organization and religious life of Gwembe Tonga migrants, the demographic structure of Kulaale homesteads (their organization on the landscape and their demographic composition), the interplay between agency and vulnerability in children’s daily lives, and the role of the state in shaping Kulaale residents’ perceptions of and interactions with the surrounding environment. This story of Gwembe Tonga migrants’ gendered and aged experiences of environmental change unfolds in the context of competing national economic strategies—frontier development wildlife conservation. This dissertation concludes that women, men, girls, and boys are all physically and economically vulnerable to the changes associated with frontier development, conservation policy, and environmental change, with social, political, and economic factors prompting them to experience vulnerability in aged and gendered ways.
53

ASSESSING ECOSYSTEM SERVICES FROM THE FORESTRY-BASED RECLAMATION OF SURFACE MINED AREAS IN THE NORTH FORK OF THE KENTUCKY RIVER WATERSHED

Gurung, Kumari 01 January 2018 (has links)
Land Use Land Cover (LULC) changes can take place at the expense of degrading environmental conditions and undermining ecosystem’s capacity to deliver benefits to people. In the Appalachian region, surface mining for coal is a major driver of LULC change. The Surface Mining Control and Reclamation Act (SMCRA) of 1977 requires mine site reclamation but typical reclamation practices often result in land cover dominated by grass and shrubs. The Forestry Reclamation Approach (FRA) is a promising reclamation strategy but not in widespread use by industry. Assessing ecosystem services that can be obtained from a forest landscape may help policy-makers and other stakeholders fully understand the benefits of forestry based reclamation. The objectives of this study are to 1) identify how surface mining and reclamation changed the LULC of a watershed encompassing the north fork of the Kentucky River 2) assess the biophysical value of four major ecosystem services under the contemporary LULC condition and 3) assess the benefits of the FRA scenario in the provision of ecosystem services. Geographic Information System (GIS) was used to study the LULC change and InVEST software models for ecosystem services assessment. The results indicate that watershed’s forest area has decreased by 7,751 hectares from 2001 to 2011 and mining activity may have contributed 75% of the change in LULC. Barren and grassland land covers provide less carbon storage, yield more water, and export more sediments and nutrients than forests. At the watershed level, the FRA modeled scenario increased carbon storage (13%) and reduced water yield (5%), sediment export (40%) and nutrient export (7%). This study provides critical information regarding the ecological benefits of Forestry Reclamation Approach to assist policy and decision making in this region even considering the modeling and data limitations.
54

Advancing cumulative effects assessment methodology for river systems

Seitz, Nicole Elyse 14 April 2011
Increased land use intensity has adversely affected aquatic ecosystems within Canada. Activities that occur over the landscape are individually minor but collectively significant when added to other past, present, and reasonably foreseeable future actions, and are defined as cumulative effects. Existing approaches to cumulative effects assessment for river systems within Canada are ineffective. This thesis aims to improve the practice of cumulative effects assessment by evaluating current methodology for linking landscape change and river response over a large spatiotemporal scale. As part of this goal, I offer a framework for better incorporating science into current practices for cumulative effects assessment. The framework addresses the challenges involved in cumulative effects assessment, such as defining appropriate spatial and temporal scale, complex ecological and hydrologic pathways, predictive analysis, and monitoring. I then test the framework over a large spatiotemporal scale using a case study of the lower reaches of the Athabasca River Basin, Alberta. Three objectives are addressed: 1) changes in land use and land cover in the lower ARB for several census dates (1981, 1986, 1991, 1996, 2001) between 1976 (historic) and 2006 (current day) are identified; 2) linkages between landscape change and river water quality and quantity response are evaluated; and 3) results of the different methods used to link landscape stressors with stream responses are compared. Results show that the landscape has changed dramatically between 1976 and 2006, documented by increases in forest harvesting, oil sands developments, and agricultural intensity. Secondly, results suggest that linear regression tests combined with regression trees are useful for capturing the strongest associations between landscape stressors and river response variables. For instance, water abstraction and agricultural activities have a significant impact on solute concentrations. This suggests that water abstraction and agriculture are important indicators to consider when conducting a watershed cumulative effect assessment on a similar spatiotemporal scale. The thesis has strong implications for the need for improved water quality and quantity monitoring of Canada‟s rivers. The research provides a means of identifying appropriate tools for improved watershed cumulative effects assessment for scientists and land managers involved in the environmental impact assessment process and protection of Canada‟s watersheds.
55

Advancing cumulative effects assessment methodology for river systems

Seitz, Nicole Elyse 14 April 2011 (has links)
Increased land use intensity has adversely affected aquatic ecosystems within Canada. Activities that occur over the landscape are individually minor but collectively significant when added to other past, present, and reasonably foreseeable future actions, and are defined as cumulative effects. Existing approaches to cumulative effects assessment for river systems within Canada are ineffective. This thesis aims to improve the practice of cumulative effects assessment by evaluating current methodology for linking landscape change and river response over a large spatiotemporal scale. As part of this goal, I offer a framework for better incorporating science into current practices for cumulative effects assessment. The framework addresses the challenges involved in cumulative effects assessment, such as defining appropriate spatial and temporal scale, complex ecological and hydrologic pathways, predictive analysis, and monitoring. I then test the framework over a large spatiotemporal scale using a case study of the lower reaches of the Athabasca River Basin, Alberta. Three objectives are addressed: 1) changes in land use and land cover in the lower ARB for several census dates (1981, 1986, 1991, 1996, 2001) between 1976 (historic) and 2006 (current day) are identified; 2) linkages between landscape change and river water quality and quantity response are evaluated; and 3) results of the different methods used to link landscape stressors with stream responses are compared. Results show that the landscape has changed dramatically between 1976 and 2006, documented by increases in forest harvesting, oil sands developments, and agricultural intensity. Secondly, results suggest that linear regression tests combined with regression trees are useful for capturing the strongest associations between landscape stressors and river response variables. For instance, water abstraction and agricultural activities have a significant impact on solute concentrations. This suggests that water abstraction and agriculture are important indicators to consider when conducting a watershed cumulative effect assessment on a similar spatiotemporal scale. The thesis has strong implications for the need for improved water quality and quantity monitoring of Canada‟s rivers. The research provides a means of identifying appropriate tools for improved watershed cumulative effects assessment for scientists and land managers involved in the environmental impact assessment process and protection of Canada‟s watersheds.
56

Effect of Brush Vegetation on Deep Drainage Using Chloride Mass Balance

Navarrete Ganchozo, Ronald J. 2009 December 1900 (has links)
Groundwater use is of fundamental importance to meet rapidly expanding urban, industrial, and agricultural water requirements, particularly in semiarid zones. To quantify the current rate of groundwater recharge is thus a prerequisite for efficient and sustainable groundwater resource management in these dry areas, where such resources are often the key to economic development. Increased groundwater recharge has been documented where native vegetation or forest/shrub land was converted to grassland or pasture, or where the land was cleared for agricultural purposes. The basic argument for increased recharge is that evapotranspiration, primarily interception and transpiration, is higher in shrublands than grasslands. Chloride mass balance (CMB) has been used to estimate ancient recharge, but recharge from recent land-use change has also been documented, specifically where vegetation has been altered and deep-rooted species replaced with shallow-rooted grasses. Chloride concentrations are inversely related to recharge rates: low Clconcentrations indicate high recharge rates as Cl- is leached from the system; high Cl concentrations indicate low recharge rates since Cl- accumulates as a result of evapotranspiration. The objectives were (1) to assess the hypothesis that removal of woody-shrub vegetation and replacement with grasses increases deep drainage, (2) to quantify the amount of deep drainage after land-use change, and (3) to provide science-based data for a better understanding of changing land-use impacts on deep drainage. Eight soils from five locations in the Central Rolling Red Plains near Abilene and Sweetwater were sampled. Each location consisted of a pair of similar soils with contrasting vegetative cover: shrubland and grassland. At each site three to five soil cores were taken as deep as possible and samples were taken by horizon, but horizons were split when their thickness exceeded 0.25 m. Soil Cl- profiles under shrubland at three sites showed that virtually no water escapes beyond the root zone. High Cl- concentrations and inventories reflect soil moisture fluxes that approached 0 mm yr-1 with depth. Evapotranspiration may be largely responsible for Cl- enrichment in those profiles. Surprisingly, soil moisture flux past 200 cm under juniper woodlands was the highest with 2.6 mm yr-1. Evapotranspirative Cl- enrichment in the upper 300 cm was not observed and may suggest a different water uptake mechanism for this plant community. Soil Cl- profiles showed increased recharge rates under grassland vegetation ecosystem. Estimated deep drainage past 200 cm of 0.1 to 1.3 mm yr-1 was observed. Low Cl- concentrations and inventories suggest a leaching environment that may be in response to changes in land use/land cover.
57

Public conservation land and economic growth in the northern forest region /

Lewis, David J. January 2001 (has links)
Thesis (M.S.) in Resource Economics and Policy--University of Maine, 2001. / Includes vita. Includes bibliographical references (leaves 65-67).
58

The influence of settlement patterns on agricultural productivity in Central Sulawesi Indonesia /

Abdullah, Rahman. January 2000 (has links)
Thesis (doctoral)--Universität, Göttingen, 2000.
59

Landscape Scale Impacts of Sea Level Rise and Elevation Changes Along the Matagorda Fault in Matagorda, Texas

Cline, Marie 2012 August 1900 (has links)
Movement of growth faults, a type of normal fault which is formed during sedimentation and is characterized by having greater vertical thickness on the downthrown fault side, on barrier islands contributes to wetland losses. The opening objective of this study was to quantify land cover change within a Matagorda, Texas wetland that results from sea level rise and elevation change over time due to coastal faulting. The closing objective of this study was to simulate land cover conversion as a function of relative sea level rise (RSLR) within the wetland and to compare and contrast the impact of specific rates of both fault-induced elevation change and predicted International Panel on Climate Change (IPCC) sea level rise projections. To accomplish these objectives a time series of aerial images was classified using automated unsupervised classification and hand digitization. After classification, total wetland losses on both the upthrown and downthrown sides of the fault were evaluated as a function of spatial distance from the fault plane. This classified product was draped over a digital elevation model (DEM) layer to evaluate elevations of land cover classes and model potential future outcomes based on RSLR. Classification results show that while wetland loss occurred on both sides of the fault, losses were far more extensive on the downthrown side. It was concluded that this vertical fault movement impacts wetland losses, especially on the downthrown side. Modeling results show that rapid water level rise can force wetland land cover class conversion regardless of whether this relative rise is caused by vertical fault displacement or eustatic sea level rise, resulting in the destruction of vital wetland areas. Current recorded conditions of sea level rise along the Texas Gulf Coast leave a grim outlook for regions similar to this study area.
60

The social construction of landscape continuity on the Niagara Escarpment and Oak Ridges Moraine : whose continuity? whose landscapes? /

Foster, Jennifer. January 2005 (has links)
Thesis (Ph.D.)--York University, 2005. Graduate Programme in Environmental Studies. / Typescript. Includes bibliographical references (leaves 242-265). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:NR19834

Page generated in 0.1116 seconds