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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.
111

Protecting Biscayne: An Analysis of Strategies for the Protection of Biscayne National Park

Harvey, Janell M 04 November 2004 (has links)
Biscayne National Park is located off the southeast coast of Florida and attracts approximately half a million visitors annually. Managers of Biscayne National Park are proposing a new General Management Plan (GMP) in order to update the recreational and commercial use of resources in the park. A Fishery Management Plan (FMP) is also being drafted simultaneously in conjunction with the Florida Fish and Wildlife Conservation Commission in order to address concerns associated with management of fish stocks within the park. The proposed plan alternatives of the GMP and the recommendations of the FMP were developed in response to the negative impacts on the park's marine ecosystem due to exponential population growth of the adjacent Miami metropolitan area. Problems associated with decreasing water quality, habitat degradation, and species exploitation contribute to the diminishing integrity of resources in the park and surrounding area. Currently commercial and recreational fishing are allowed in most of Biscayne National Park. The National Park Service's proposed alternatives are highly complex in order to make an attempt at appeasing stakeholder interests. In addition the recommendations of the FMP join the GMP alternatives in omitting marine reserves, a management practice that is widely thought by the scientific community to be an important step in marine resource rehabilitation. At present, there is a noticeable absence of scientific information and lack of participation of scientists in management decisions. Biscayne National Park would ultimately benefit by incorporating marine reserves into the park, and adjusting them based on scientific studies conducted by an appointed Scientific Advisory Board. Partnerships with state, federal, and international agencies could promote the idea of being a part of a marine reserve network for optimal resource protection in the Caribbean. An increase in revenue from a permit system and entrance fees would also promote enforcement and protection of park resources. Simple but strong regulation in the park could also help alleviate enforcement problems. In addition education of park resource users should be expanded inside and outside the park.
112

Managing Regional Water Resources Amidst Rapid Urbanization in Southwest Florida: A Case Study

Caesar, Nicole Owusua 11 July 2014 (has links)
Experts and organizations involved in freshwater resources management have emphasized the importance of long-term urban resource planning and management that considers the tight coupling which exists between human - nature - technology systems. The resistance of contemporary urban growth efforts to consider resource carrying capacities and ecosystem requirements has led to costly unintended consequences including the deterioration of natural capital and their associated ecosystem services, and the degradation of water resource flows. As these problems continue to worsen, resource experts have called for the development of a new water resource management paradigm inclusive of various sustainability criteria. Historically water-rich Florida has demonstrated increased resource strain over the past four decades, in spite of the creation of some of the nation's most comprehensive water resource and growth management legislation. The Southwest Florida Water Management District was originally created to manage regional flooding in 1961 and has undergone a tremendous expansion in statutorily mandated resource responsibilities over the past 40 years. This case study utilized semi-structured surveys of current and former agency employees to examine the agency's expansion into integrated water resource management amidst rapid regional urbanization.
113

The integration of nature conservation and community development in Nepal's protected natural areas and buffer zones

Ryan, Robert J., University of Western Sydney, College of Health and Science, School of Natural Sciences January 2008 (has links)
This thesis has endeavoured to enhance the knowledge and effectiveness of integrated conservation and development projects (ICDPs) as a model for the management of conservation areas and the buffer zones to national parks and reserves in Nepal. ICDPs evolved as it was recognised that the Western model of protected natural area management imposed costs on poor rural communities in developing countries and often failed to achieve nature conservation objectives. The ICDP concept was questioned when, after many years of mostly development effort in several developing countries, ICDPs did not provide an appropriate contribution to nature conservation. An ICDP in Nepal that provided considerable benefit to local people and greatly enhanced nature conservation is provided to establish that the ICDP concept is valid. The question that initiated this research was why some ICDPs fail to contribute to nature conservation while others are successful. The ICDP process is based on the assumption that the welfare of people who rely on resources from within protected natural areas is central to the pursuit of nature conservation and has priority in that nature conservation objectives can only be achieved where the wellbeing of local people and their access to the resources they require has been assured. The establishment of a nature conservation estate in developing countries is both an ecological problem and a social problem. The social problem is one of poverty. ICDPs in Nepal’s protected natural areas have been studied using qualitative research methods and a contextual constructionist approach that is central to the study of social problems. The evidence suggests that ICDP agencies have accepted assumptions that sustainable development and poverty alleviation will lead to the conservation of biodiversity. This thesis argues that sustainable resource use can not ensure the conservation of biodiversity yet paradoxically the sustainable use of resources in one place may lead to biodiversity conservation in more remote places where human impact is minimal. The variables associated with different settings are such that the outcomes of interventions designed to achieve ICDP objectives are not always predictable. The research suggests that assumptions about the outcomes of interventions should be treated with caution. Monitoring interventions can help ensure the desired outcomes are achieved but ICDP intervention monitoring in Nepal has been neglected. Numerous reports and evaluations detail input and effort rather than outcomes. The results include a recommendation to apply the principles of action research and adoption of a structured process for monitoring and evaluation of progress towards clearly stated objectives for the project and for individual interventions. / Doctor of Philosophy (PhD)
114

Biodiversity measurement, species interactions and sustainability

Gerber, Nicolas, Economics, Australian School of Business, UNSW January 2006 (has links)
Throughout the last two decades, biodiversity has been increasingly acknowledged as a valuable asset. However there are numerous challenges to managing the asset. Firstly, there is no universally accepted measure of biodiversity per se. As a consequence, rather than measuring the intrinsic value of biodiversity the focus has typically shifted to valuing biodiversity services. Secondly, biodiversity issues should not be considered in a vacuum, but rather alongside general natural resource management problems. Conservation agencies and regulators alike would greatly benefit from more transparent biodiversity targets for conservation policies and natural resource management. This thesis makes a number of contributions to meet these challenges including measuring biodiversity, modelling diverse ecosystems and considering biodiversity outcomes in the management of an environmental resource. To value biodiversity, it is essential to measure it. Focusing on pairwise genetic dissimilarities at the species level, this thesis develops two models for measuring biodiversity. An axiomatic diagnosis of the existing and new measures is presented. This comparison suggests that the adequate biodiversity measure depends on the context. The diversity measures describe the biodiversity catalogue available at a given point in time. Modelling biodiversity is important for forecasting the impact of conservation decisions and understanding the future value of biodiversity. The importance of each species, however, depends on its role in the ecosystem as well as its genetic diversity. The interactions between species are therefore investigated and described, using a new model built around CES production functions. Three existing models based on predator-prey equations are extended to the multi-species case. These interaction models provide the necessary link for biodiversity maintenance over time. The four models are compared using simulations and an axiomatic approach. This approach shows that the new model performs well, offers the flexibility required to describe different types of ecosystems and is less data intensive. Finally, a case study of natural resource exploitation is presented, illustrating the idea that biodiversity loss can have direct economic implications in natural resource management. The model shows the impact of market structures on the extraction path of the resource and the distribution of the resource rent.
115

Effects of a pulsing hydroperiod on a created riparian river diversion wetland

Fink, Daniel Francis, January 2007 (has links)
Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 206-221).
116

Towards an Ecosystem Approach for Non-Target Reef Fishes: Habitat Uses and Population Dynamics of South Florida Parrotfishes (Perciformes: Scaridae)

Molina-Ureña, Helena 14 May 2009 (has links)
The goal of this research was to develop statistically robust ecosystem-based approaches, while optimizing data acquisition on relatively unexploited fish species in South Florida reefs, i.e., parrotfishes, Family Scaridae, in Biscayne Bay (with seasonal roller frame beam trawl surveys, 1996-2000) and Florida Keys (with annual Reef Fish Visual Censuses, 1997-2001), by following these steps: (I) analysis of information gaps for the stocks, including systematics, biogeography, population dynamics, reproductive ecology, trophodynamics, habitat use, and fisheries dynamics of Western Atlantic parrotfishes; (II) determination of primary research objectives from prioritization in Step I; (III) determination of essential fish habitats, ontogenetic shifts, migrations, and reef-seagrass habitat, from integration of stratified sampling design for fisheries-independent surveys, habitat selection theory-based analyses, and length-based analyses; (IV) estimation of population dynamics and fisheries-specific parameters encompassing life history demographics from empirical data or comparisons to theoretical expectations adapted to local conditions; (V) simulation modeling of a realistic range of fishing scenarios and demographic characteristics to evaluate the efficacy of potential traditional fisheries and spatial management strategies; and (VI) application of sampling optimization procedures and fisheries ecology approaches. Four scarid species had an estimated combined abundance of ca. 36.8 x 106 individuals in the Florida Keys. Connectivity among seagrass beds, coral reefs and deep waters had three major patterns: seagrass dwellers, reef dwellers, with inshore-to-offshore ontogenetic , and a seagrass-reef connection, using Biscayne Bay as an important recruitment ground. Marine protected areas of the Florida Keys National Marine Sanctuary did not show effects on abundance, size composition or spatial distribution of any parrotfish studied. Simulations suggested relatively short longevities (5-10 years), moderate body growth curvature, high instantaneous natural mortality rates (0.3-0.6 y super minus one), and low annual survival rates (27-54%). Simulated estimates of fishing mortalities ranged from 0.3 to 0.6 y super minus one, indicating low levels of exploitation, but low Spawning Potential Ratios (SPR = 23.5-26%). Proposed potential exploitation based on a legal minimum size equal to their size at first maturity and fishing rates equal or below to their natural mortality should secure SPR values at 45-48%.
117

Effects of variation in ecosystem carryover on biodiversity and community structure of forest floor bryophytes and understory vascular plants : a retrospective approach

Traut, Bibit Halliday 21 November 1994 (has links)
Graduation date: 1995
118

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.
119

Contribution of Nitrogen Fixation to Planktonic Food Webs North of Australia

Drexel, Jan Peter 16 November 2007 (has links)
Nitrogen fixation is no longer considered to be a minor factor of the nitrogen cycle in oceanic ecosystems. Recent geochemical and biological efforts have led to a significant increase in the estimated input of nitrogen to marine ecosystems by biological fixation, while molecular studies have increased our knowledge of the number and diversity of nitrogen fixers known to be active in the ocean. Although Trichodesmium spp. have long been viewed as the primary marine nitrogen fixers, recent efforts have shown that various members of the picoplankton community are also actively involved in nitrogen fixation. The relative abundance of different nitrogen fixers is an important ecosystem parameter since nitrogen fixers may differ significantly in their physiology, life history and ecology. Here we combine rate measurements and stable isotope natural abundance measurements to constrain the impact of N2 fixation in the waters north of Australia. Samples were collected in the Coral, Arafura, and East Timor Seas, thus spanning three distinct hydrographic regions. Our data show that Trichodesmium has a significant influence on the stable nitrogen isotope ratios of particulate and zooplankton biomass and suggest that Trichodesmium is a significant source of nitrogen for the pelagic ecosystem. Based on stable carbon isotope ratios, it is also likely that the pathways are indirect and nitrogen fixed by Trichodesmium enters the higher trophic levels via decomposition as dissolved organic and inorganic nitrogen. Picocyanobacteria showed high diazotrophic activity at some stations, but unlike Trichodesmium, their N2 fixation rate was not reflected in the stable N isotope ratios of particulate and zooplankton biomass. Our results suggest an important N contribution to biomass by diazotrophs in the Coral Sea, Arafura Sea and East Timor Sea.
120

The role of collaboration in everglades restoration

Frank, Kathryn Irene 21 August 2009 (has links)
This dissertation examined the impacts of multiple collaborative planning and implementation processes on ecosystem management of the Everglades wetlands of South Florida. In particular, the research focused on collaboration's role in (1) reducing phosphorus pollution in runoff from the Everglades Agricultural Area in the historic northern Everglades and (2) improving the water flow regime in Shark Slough of the southern Everglades. Restoration of the greater Everglades watershed is the largest such initiative in the world, and it may also be the most collaborative, with scores of these processes used at various scales since the mid-1960s. Ecosystem management is the most advanced approach to environmental governance, and its three tenets of integrative, adaptive, and ecologically protective governance provide a framework for evaluating environmental planning processes. Proponents of collaborative processes believe they are exceptionally suited to promoting the tenets of ecosystem management. Critics of collaboration, however, are concerned with the potential for cooptation of environmental interests, among other issues. Using qualitative case study methodology, the research found that collaborative processes improved ecosystem management, but not to the degree expected by collaboration proponents. Collaborative processes were integrative of values, information, activities, and political support across the ecosystem, yet integration had biases and limits as a result of groups' strategic behaviors and processes' emphasis on reaching agreement rather than fully exploring the issues. Cooptation of environmental interests was not a significant problem. Collaborative processes promoted adaptation and social learning in specific cases, but at a macro level helped to maintain the status quo of the dominant water management agencies and technocratic paradigms. Process outcomes were protective of ecological health in that they made steady, incremental progress towards ecological restoration. Progress had significant setbacks however, because collaboratively developed policies were subject to capture by economic interests. Despite the collaborative improvements in ecosystem management, ecological health remains a distant and uncertain prospect for the Everglades.

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