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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.
181

Phosphate-associated phenotype plasticity as a driver of cattail invasion in the sawgass-dominated Everglades

Unknown Date (has links)
In plants, phenotypic plasticity, the ability to morphologically adapt to new or broad environmental conditions, is a consequence of long-term evolutionary genetic processes. Thus, plants adapted to low phosphate (P) environments exhibit only limited plasticity to take advantage of nutrient enrichment, a global phenomenon in terrestrial and aquatic environments. In the face of anthropogenic P-enrichment, low nutrient adapted resident plant species are frequently displaced by species with high morphological and genetic plasticity. However, it remains unclear whether plasticity is systemically expressed across molecular, biochemical, physiological, and morphological processes that ultimately contribute to the root and shoot phenotypes of plants. In this study, we demonstrated high plasticity in root-borne traits of sawgrass (Cladium jamaicense), the dominant plant species of the P-impoverished Everglades, and counter the idea of inflexibility in low P adapted species. However, sawgras s expressed inflexibility in processes contributing to shoot phenotypes, in contrast to cattail, which was highly plastic in shoot characteristics vii in response to P enrichment. In fact, plasticity in cattail shoots is likely a function of its growth response to P that was globally regulated by P-availability at the level of transcription. Plasticity and inflexibility in the growth of both species also diverged in their allocation of P to the chloroplast for growth in cattail versus the vacuole for P storage in sawgrass. In the Everglades, anthropogenic P-enrichment has changed the environment from a P-limited condition, where plasticity in root-borne traits of sawgrass was advantageous, to one of light-competition, where plasticity in shoot-borne traits drives competitive dominance by cattail. / We hypothesize that these shifts in plasticity competitive advantage from root to shoots has been a major driver of cattail expansion in the Everglades ecosystem. Further, this understanding of how natural plant species adapt and shift in response to nutrient availability could also be used a model system to optimize agricultural systems to increase efficiencies in food production and protect low nutrient adapted natural systems from cultural eutrophication. / by James Webb. / Vita. / Thesis (Ph.D.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 200?. Mode of access: World Wide Web.
182

Development of a remote sensing technique for woody vegetation in Rotenberger Wildlife Management Area

Unknown Date (has links)
The Florida Fish and Wildlife Conservation Commission lacks a viable method for monitoring woody vegetation in expansive wetland communities, such as the Florida Everglades. This study used aerial photographs of Rotenberger Wildlife Management Area in southeastern Palm Beach County, Florida to develop techniques for remotely monitoring changes in woody vegetation. Imagery from 2006, 2008, and 2010 were classified into woody and non-woody categories using Adobe Photoshop's Magic Wand Tool. Selection was performed with a bias toward over classification, as project objectives required identifying as many trees as possible. Classified pixels in Time 1 within 4 feet (2 pixels) of classified pixels from Time 2 were considered the same canopy. Overall accuracy for the study was 98%. / by Sarah Franklin. / Thesis (M.A.)--Florida Atlantic University, 2011. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web.
183

Comparative legal frameworks for payments for ecosystem services

Jackson, Sarah January 2018 (has links)
In recent decades, the concept of ecosystem services has deepened our appreciation of the myriad benefits provided by ecosystems, and the risks to human societies posed by ecosystem degradation. There is a growing realisation that problems traditionally considered to be outside the environmental policy arena are in truth strongly connected to the environment: ecosystems underlie issues spanning climate, energy, food, water, urban planning, human health, economic development, social justice, and national security. Payments for ecosystem services (PES) create positive financial incentives for the protection and restoration of ecosystems, and represent one way to better represent the value of ecosystem services across a range of sectors. PES schemes are gaining traction in climate mitigation and biodiversity protection strategies, and most of all in the water sector. PES is complementing traditional approaches to water management and helping to address deteriorating water quality, declining water flows, and flooding. This thesis takes a legal perspective, examining the role of legal frameworks in the design and administration of PES. It focuses on PES aimed at protecting freshwater ecosystem services, and considers how legal frameworks can incorporate PES into strategies for drinking water provision. It examines an emerging body of law relating directly to PES, and provides an opportunity to consider some of the leading examples of the ES concept being reflected in law. It distinguishes three broad categories of legal frameworks that establish, regulate or enable PES. A comparative methodology is applied to an analysis of case studies of legal frameworks for PES from: Costa Rica, Ecuador, Peru, Colombia, New York, England and Ontario. This analysis draws out conclusions about how the law relates to key policy issues around ES and PES, and different approaches to developing legal frameworks to guide PES, depending on different contexts and policy objectives.
184

Valuing the Invaluable: Piquant Georgia Low-Country Marsh Ecosystem Services

Unknown Date (has links)
Coastal ecosystems, such as the salt marsh of the Georgia coast, have long been valued for decision-making purposes based on market-values of goods and services including: fishery landings, hedonic pricing of waterfront homes, and tourism dollars. These values do not show the full picture of services provided by these ecosystems. Using focus group discussions and key informant interviews I investigate socio-cultural values and benefits provided by salt marsh ecosystems in central coastal Georgia. Participants noted that through their experiences in marshes they developed a desire to be stewards. This desire, coupled with the industrial pollution, residential development, and sea-level rise threats in the area result in a need for cooperative conservation and thus better enforcement of existing regulations. This relational value persisted across geographic locations and sample populations. My results show the importance of utilizing diverse members of community to elicit qualitative value statements. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection
185

Marsh Ecosystem Services, Benefits, and Perceptions of Value: Case Studies in Massachusetts, Virginia, and Georgia

Unknown Date (has links)
Human reliance on the goods and services provided by ecosystems and the global decline in the health of many of these ecosystems, necessitates ecosystem valuation for the purposes of decision-making and conservation policy. The literature suggests that conventionally employed economic valuation methods have been unsuccessful in capturing the full scope of the benefits ecosystems provide, particularly those benefits that are considered cultural. This research explores public perceptions of salt marsh value through the use of focus groups in marsh-adjacent communities in Massachusetts, Virginia, and Georgia. Results suggest that in case study communities, outdoor experiences in salt marshes inspire serenity in Massachusetts, shape shore and “marsh” identities in Virginia, and promote stewardship cultivation in Georgia. Perceived threats to these benefits, such as the threat of residential development, industrial pollution, and increasing flood risk, together constitute the context for various community responses related to marsh protection. Results contribute to existing economic valuations. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection
186

Ekologiska fotavtryck för koldioxidutsläpp för Stockholms län, Norrbottens län och Stockholms läns landsting : En kritisk metodgranskning baserad på kvantitativa data

Johansson, Bodil January 2007 (has links)
<p>Human existence and welfare depend on functional ecosystems. Ecosystems are critical to sustain life-support services for human well-being. One method that visualizes that humanity requires ecosystem services for resource consumption and assimilation of produced waste is ecological footprints. This study focuses on the ecosystem service carbon sequestering. A quantification of this ecosystem service showed the potential for accumulation of carbon in different ecosystems in Stockholm and Norrbotten County for the years of 1995 and 2004. This study also provides an estimate of the ecosystem area that is appropriated to accumulate all carbon from total carbon dioxide emissions in Stockholm and Norrbotten County respectively. The appropriated ecosystem area represents the ecological footprint. The ecological footprint is also calculated for Stockholms läns landsting`s total carbon dioxide emissions in 2004. The total potential for accumulation of carbon is lower in the ecosystems in Stockholm County in 2004 than in 1995 and the corresponding figure for Norrbotten County has increased. The results indicate that the total potential for carbon accumulation in Stockholm County was approximately 427 kton C year-1 in 1995 and 352 kton C year -1 in 2004. In 1995 the ecosystems in Stockholm County could assimilate 26% of the county’s total emissions whereas the figure for 2004 was 21%. In Norrbotten County, the total potential for accumulation was approximately 2 824 kton C year -1 in 1995 and 2 983 kton C year -1 in 2004. The ecosystem area that is appropriated to assimilate total emissions of carbon dioxide was smaller in 2004 than in 1995 in Stockholm County and larger in Norrbotten County. The ecological footprint for total carbon dioxide emissions in Stockholm County was 12 696 km2 in 1995 and 12 506 km2 in 2004. The corresponding estimate for Norrbotten County indicate that the ecological footprint for total carbon sequestering was 14 457 km2 in 1995 and 32 146 km2 in 2004. The result shows that both regions require large areas of ecosystem to absorb total emissions of carbon dioxide. Stockholms läns landsting´s ecological footprint was 409 km2, which corresponds to 3.3 % of the County’s total ecological footprint. Stockholm County depends on ecosystem areas outside the region for assimilation of the region’s total emissions of carbon dioxide. According to the results Norrbotten County is self-sufficient with regard to the ecosystem service carbon accumulation. This study also includes a discussion of the advantages and limitations of the ecological footprint as a methodology. The received results serve as the starting point for this discussion. Ecological footprints are pedagogic and communicative indicators and can therefore reach out to a broad audience which is a great advantage with the method. It is a static measure and is therefore incapable of giving any presages. Ecological footprints do not take the dynamics and complexity of ecosystems into account and can therefore not provide any information about the possibilities for ecosystems to deliver ecosystem services at the same quality and quantity in the future. The method does not take socio-economic factors into consideration. For these reasons, ecological footprint should not be used as an indicator for sustainability. On the other hand, ecological footprint can illustrate why an ecologically sustainable development is necessary by visualizing that human welfare and existence rely on functional ecosystems.</p>
187

Ekologiska fotavtryck för koldioxidutsläpp för Stockholms län, Norrbottens län och Stockholms läns landsting : En kritisk metodgranskning baserad på kvantitativa data

Johansson, Bodil January 2007 (has links)
Human existence and welfare depend on functional ecosystems. Ecosystems are critical to sustain life-support services for human well-being. One method that visualizes that humanity requires ecosystem services for resource consumption and assimilation of produced waste is ecological footprints. This study focuses on the ecosystem service carbon sequestering. A quantification of this ecosystem service showed the potential for accumulation of carbon in different ecosystems in Stockholm and Norrbotten County for the years of 1995 and 2004. This study also provides an estimate of the ecosystem area that is appropriated to accumulate all carbon from total carbon dioxide emissions in Stockholm and Norrbotten County respectively. The appropriated ecosystem area represents the ecological footprint. The ecological footprint is also calculated for Stockholms läns landsting`s total carbon dioxide emissions in 2004. The total potential for accumulation of carbon is lower in the ecosystems in Stockholm County in 2004 than in 1995 and the corresponding figure for Norrbotten County has increased. The results indicate that the total potential for carbon accumulation in Stockholm County was approximately 427 kton C year-1 in 1995 and 352 kton C year -1 in 2004. In 1995 the ecosystems in Stockholm County could assimilate 26% of the county’s total emissions whereas the figure for 2004 was 21%. In Norrbotten County, the total potential for accumulation was approximately 2 824 kton C year -1 in 1995 and 2 983 kton C year -1 in 2004. The ecosystem area that is appropriated to assimilate total emissions of carbon dioxide was smaller in 2004 than in 1995 in Stockholm County and larger in Norrbotten County. The ecological footprint for total carbon dioxide emissions in Stockholm County was 12 696 km2 in 1995 and 12 506 km2 in 2004. The corresponding estimate for Norrbotten County indicate that the ecological footprint for total carbon sequestering was 14 457 km2 in 1995 and 32 146 km2 in 2004. The result shows that both regions require large areas of ecosystem to absorb total emissions of carbon dioxide. Stockholms läns landsting´s ecological footprint was 409 km2, which corresponds to 3.3 % of the County’s total ecological footprint. Stockholm County depends on ecosystem areas outside the region for assimilation of the region’s total emissions of carbon dioxide. According to the results Norrbotten County is self-sufficient with regard to the ecosystem service carbon accumulation. This study also includes a discussion of the advantages and limitations of the ecological footprint as a methodology. The received results serve as the starting point for this discussion. Ecological footprints are pedagogic and communicative indicators and can therefore reach out to a broad audience which is a great advantage with the method. It is a static measure and is therefore incapable of giving any presages. Ecological footprints do not take the dynamics and complexity of ecosystems into account and can therefore not provide any information about the possibilities for ecosystems to deliver ecosystem services at the same quality and quantity in the future. The method does not take socio-economic factors into consideration. For these reasons, ecological footprint should not be used as an indicator for sustainability. On the other hand, ecological footprint can illustrate why an ecologically sustainable development is necessary by visualizing that human welfare and existence rely on functional ecosystems.
188

Impacts of self-organizing mechanism and topography on wetland ecosystem dynamics

Cheng, Yiwei 09 May 2013 (has links)
Understanding the first order controls over resource cycling and limitation in ecosystems is critical for predicting ecosystem response to disturbances. Topography and vegetation self-organizing mechanisms are first order controls over resource fluxes across the landscape. Topography controls downslope flow of resources (i.e water and nutrients). Through spatial feedbacks, vegetation is able to actively modify its environment and maximize resource flows towards it. To date, the impacts of these controls on ecosystem dynamics have mostly been investigated separately. As such, there is a knowledge gap in the understanding of how these first order controls together dictate the dynamics of the ecosystem. This dissertation aims to gain a better understanding of how self-organizing mechanisms and topography operate together to affect wetland ecosystem dynamics. A spatially explicit, wetland vegetation patterning model that includes for both vegetation self-organizing control and topographic control is developed (Nutrient Depletion Model, NDM). The model describes a scale dependent feedback between vegetation, transpiration and nutrient accumulation that drives the formation of vegetation patterns. The model is applied to investigate the effects of topography and self-organizing mechanisms on form and orientation of vegetation patterns and vegetation growth dynamics of wetland ecosystems. Results show that the two first order controls synergistically impact the formation of the various patterns as observed in wetland ecosystems. Results also show the following: (1) Self-organizing mechanisms result in a more efficient retention of resources, which result in higher biomass in the model that include for both self-organizing mechanism and topographic control (SO+TC) than in the model that that includes only for topographic control (TC). (2) However, when resources or topographic gradients increase or annual rainfall decrease, the vegetation growth dynamics of the TC+SO and TC models converge. The NDM is applied to arctic Alaska to investigate how do the two first order controls impact present and future C-N dynamics of an arctic ecosystem. Simulation results show no significant difference in the dynamics between the SO+TC model and the TC model. The climate change simulation results suggest that changes in daily variability of temperature and precipitation can impact ecosystem dynamics as much as the changes in mean temperature and precipitation. Results from this dissertation provide a more complete picture on the relative roles of the two first order controls over ecosystem nutrient cycling and vegetative growth dynamics. Finally, in this thesis, in order to simulate small-scale feedbacks over large spatial domains, the NDM is implemented in a GPU computing language, which accelerates computational simulation by at least two orders of magnitude. These tools for grid-based simulations can provide a platform for using GPUs in other areas of scientific investigation.
189

Ecosystem Services Based Evaluation Framework of Land-use Management Options for Dryland Salinity in the Avon Region, Western Australian Wheatbelt

Kleplova, Klara Zoe January 2014 (has links)
Dryland-salinity management options aim to positively influence the adverse human-induced processes which lead to salinisation of top-soil. Specifically, the processes causing dryland-salinity are rising saline groundwater table and soil erosion. In the Avon region of Western Australia, the management options are evaluated solely on the basis of their efficiency in lowering groundwater tables. However, recently the need to take into account also their wider impact on the ecosystems' resilience has been recognised as well. Nevertheless, the tool to assess these impacts is missing. The aim of this thesis is to synthesise the missing tool from existing ecosystem services-based land-use evaluation frameworks, which would fit the environmental issue, regional socio-economic demands and the existing dryland salinity management options' efficiency evaluation framework. The thesis builds on secondary data and describes (i) the environmental issue of dryland salinity in Australia, (ii) the dryland salinity-environmental, economic, social and political environments of the Avon region, and (iii) five chosen evaluation frameworks which assess the impact of land-use on ecosystem resilience. The proposed optimal framework for the Avon region is then a combination of two existent frameworks: (i) ecosystem resilience evaluation framework &amp; (ii) the ecosystem services economic valuation framework. Where the inputs of the proposed optimal framework are: (i) soil properties, (ii) external natural and anthropogenic drivers and (iii) beneficiaries; the transfer phase is represented by the soil processes; and the output of the framework are (i) ecosystem services and (ii) their economically valued benefits.
190

Comparing and mapping ecosystem service use across interest groups in the Upper Peace River Watershed

Darvill, Rachel 04 February 2014 (has links)
The ecosystem service (ES) approach to conservation normally uses economic or biophysical assessments for valuating nature's services. In contrast, even though ES are required for human well-being, the actual uses of services by differing interest groups are rarely considered, nor are intangible cultural ES. The aim of this research was to quantify different uses for 15 cultural and provisioning ES indicators across seven groups on a regional scale, as well assess spatial differences in ES across eight groups using participatory GIS. Results demonstrate that different interest groups use ES differently; in terms of ES type, frequency of use, as well as spatial location of ES use. In particular, this work highlights the importance of considering cultural ES (e.g. aesthetic/scenic, sense-of-place) during decision making processes. Spatial locations of ES hotspots were also shown to correspond with established areas of high biodiversity, both required for effective and legitimate decisions regarding land use.

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