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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.
591

Restoration criteria on dolomite quarries on "Sierra de Mijas" mountain range

Jimenez, Alberto Jr January 2007 (has links)
<p>There are many dolomitic outcrops at Rondean sector (into the biogeographical Betic Province). Most of them, involve floral richness and vegetal endemic species due to its calcareous origin. These diverse organisms build peculiar plant communities. They can survive in extreme conditions as drought and high levels of Mg2+ cation. Many studies pronounce that these communities are unique, so they have to be conserved, and some of these plant communities are in the Habitats Directive 92/43 EC. </p><p>38% of the dolomitic outcrops can be affected by mining processes. Those particularly affected are dolomitic outcrops located in the mountains range of “Sierra Blanca” and “Sierra de Mijas”. Nowadays, there are 21 quarries in these mountains and they occupy more than 409 Ha. We have studied 11 dolomite quarries and surroundings on “Sierra de Mijas”. There is one vegetation serie on these areas (Rhamno oleoidis-Querco rotundifoliae sigmetum. Dolomitic section), knowing the plant communities we could draw with a Geographical Information System (GIS) the polygons where they are. And using the modified Botanic Value Index equation (Nieto et al., 1999) we could calculate the botanical value of these polygons. After that, we could establish a classification of the study area from the point of view of conservation interest, and we could set up new restoration criteria on these lands. </p><p>We have found that approximately the 53 % of the studied area has a high botanic value. There are many endemic taxa in the studied area and 4 species exclusive of the “Sierra de Mijas” mountain range. 90 % of the present communities are included in the Habitats Directive 92/43 CE, and three of the communities are exclusive of the studied area. This is the reason why these quarries have to be restored with a sustainable criteria.</p><p>Current restoration plans try to reforest with the climax vegetation (Quercus rotundifolia) or different species of pines (used in several previous reforestations). However, to restore a quarry these plans should include, in addition, other factors such as soil depth, structure of vegetal communities, botanic value, etc. And the Reforest Models of Valle (2004) propose sustainable restoration that could be usefull in the dolomite quarries of “Sierra de Mijas” mountain range.</p>
592

Ecosystem Restoration and Subtropical Seagrass Fishes: Insights into Salinity Effects from Habitat Selection and Preference Tests

Buck, Eric L. 20 April 2011 (has links)
The work of this Master of Science thesis project is an analysis of salinity effects on nearshore epifauna along the western shore of Biscayne Bay in southeast Florida, USA. Field collection surveys have found a high probability of occurrence of bigeye mojarra (Eucinostomus havana) in salinities near 25 ppt. In a salinity gradient observation experiment test subjects of the same species and size class were also observed more frequently at 24 ppt. In this analysis presence and abundance patterns found in field surveys were compared with behavioral results obtained in the observation tank. This apparatus provided insight into distribution patterns of the bigeye mojarra (Eucinostomus havana) and possible changes in distribution that may result from habitat changes in the future. Historically, the western shore of Biscayne Bay was more freshwater marsh than the mangrove dominated marine environment that prevails today. Changes to fresh water inputs into the Bay are planned through projects of the Comprehensive Everglades Restoration Plan (CERP). CERP is a joint Florida state and U.S. federal effort to redesign surface water flow through the canal system of South Florida, replenish the Everglades ecosystem, and restore a more natural quantity, timing, and distribution of flow into Biscayne and Florida Bays. Approved by the U.S. Congress as part of the Water Resources Development Act of 2000, CERP will be implemented by the South Florida Water Management District (SFWMD) and the U.S. Army Corps of Engineers (USACE). This plan is designed to restore the ecosystem from its freshwater core to the coastal wetlands recreating a condition close to that existing before the current system of flood control drainage canals was begun in 1903 and continued by the federal Central and Southern Florida Project in 1948 (www.evergladesplan.org). Changes are planned to divert a portion of canal flows to Biscayne Bay into coastal wetlands as sheet flow and surface runoff. Planned changes to freshwater delivery may change the habitat along the shoreline and thus the distribution of prey organisms living in this habitat. This may in turn affect predator fish important to local recreational and commercial fisheries as well as other predators such as wading birds. The analysis and prediction provided in this thesis work is important for better understanding the effects of restoration efforts on the Bay nearshore habitat and its condition as essential fish habitat, which is federally regulated by the Magnuson-Stevens Fishery Conservation and Management Act (Magnuson-Stevens, 1996). The distribution of small fish and invertebrate inhabitants of the nearshore environment and habitat environmental qualities have been recorded over the past five years from throw-trap surveys of the western shoreline of Biscayne Bay as part of a CERP-sponsored monitoring program. This pattern is correlated with salinity, but there may be other factors affecting the distribution of this species.
593

The Effect of Salinity Variability on the Mesozooplankton Community of Florida Bay

Kelble, Christopher Richard 08 May 2010 (has links)
The greater Everglades ecosystem, including Florida Bay, has undergone significant anthropogenic manipulation over the past century. These actions resulted in a series of ecologically undesirable events in the Everglades ecosystem, prompting passage of the Comprehensive Everglades Restoration Plan (CERP). It is necessary to understand the variability in, and relationship between, salinity and ecology to fully evaluate the potential effects of CERP on Florida Bay. A seven-year dataset on surface salinity along with eleven-year and eight-year datasets on mesozooplankton and planktivorous fish were analyzed. Overall, mean Bay-wide salinity varied from a low of 24.2 just after the passing of Hurricane Irene in October 1999 to a high of 41.8 near the end of a drought period in July 2001. Bay-wide mean salinity exhibited dramatic decreases, up to 0.5 per day, whereas increases in bay-wide salinity were slower, with a maximum rate of 0.1 per day. Meteorological phenomena, such as tropical cyclones and ENSO, dramatically altered the salinity patterns of Florida Bay on interannual time scales. There was a large degree of spatial heterogeneity in salinity between sub-regions of Florida Bay due to differing freshwater sources and geomorphology. Mesozooplankton abundance displayed interannual variability and a positive correlation with salinity. Both of these features were also closely correlated with abundance of the dominant planktivorous fish, Anchoa mitchilli, indicating the importance of top-down control. The hypersaline periods appear to provide a refuge from predators, allowing mesozooplankton to increase in abundance during periods of increased physiological stress. The interaction between mesozooplankton and A. mitchilli, along with its correlation to salinity, was further investigated through the development of a mechanistic model of the populations in Florida Bay. The model indicated predation alone was insufficient to control mesozooplankton populations; rather, it was necessary to incorporate density-dependence utilizing a logistic prey population. With both mechanisms the model was able to replicate the observed interannual variability pattern and positive correlation between mesozooplankton and salinity. A preliminary management scenario evaluation suggests a two to six-fold difference in A. mitchilli and mesozooplankton populations between targeted and general salinity reductions. This suggests alternative freshwater management scenarios could produce drastically different ecological consequences.
594

“The Last Dear Drop of Blood”: Revenge in Restoration Tragic Drama

Krueger, Misty Sabrina 01 May 2010 (has links)
Revenge on the English stage has long been associated with Elizabethan and Renaissance revenge tragedies, and has been all but ignored in Restoration theater history. While the shortage of scholarly work on revenge in Restoration drama might seem to indicate that revenge is not a vital part of Restoration drama, I argue that revenge on stage in the Restoration is connected with important late seventeenth-century anxieties about monarchy and political subjecthood in the period. This dissertation examines how Restoration tragic drama staged during Charles II’s reign (1660-1685) depicts revenge as a representation of an unrestrained passion that contributes to the ‘seditious roaring of a troubled nation’ of which Thomas Hobbes writes in Leviathan. This dissertation suggests that we need to assess Restoration tragic drama’s employment of acts of vengeance in order to better understand how tragic drama of the period narrates crises of kinship, kingship, and political subjecthood. In chapters addressing blood revenge, rape, female passion, and personal ambition, I examine revenge in a number of Restoration tragic dramas written for the stage between 1660 and 1685. This project shows that characters’ claims to redress wrongs committed against the civil notion of justice collapse into private, individual desires that are pathological and destructive of the state. This project on revenge has the potential to shape the way we think about revenge on stage by calling attention to revenge as a sign of self-interest at the end of the seventeenth century, an age in which a shift in thinking about monarchy and personhood was taking place. Just as Hobbes warns against the “excessive desire of Revenge,” this dissertation shows how playwrights stage revenge as a warning about the potentially destructive consequences of revenge: revenge puts not only private bodies in danger but also the public well being of the state.
595

Silvicultural Considerations for the Reintroduction of American Chestnut, <i>Castanea dentata</i>, to the Forests of the Eastern United States

Pinchot, Cornelia Cooper Wells 01 August 2011 (has links)
In anticipation of widespread planting of putatively blight-resistant hybrid chestnuts (Castanea spp.), it is critical to understand the silvics and competitive ability of the species. This dissertation examines preliminary growth and survival of several species and genetic crosses of chestnut grown as 1-0 high-quality nursery seedlings and planted in two study sites: Southeastern Kentucky (Daniel Boone National Forest; chapter 2), and Northeastern Connecticut (Yale-Myers Forest; chapter 4). The effects of three silvicultural treatments on the Daniel Boone National Forest (DBNF), and four silvicultural treatments on the Yale-Myers Forest (YM) were evaluated. Furthermore, the effect of initial seedling size on seedling performance was tested. In both studies, seedlings grew largest in height and root collar diameter in silvicultural treatments with the most available light. High mortality at the DBNF planting was caused by Phytophthora cinnamomi, ink disease, and high mortality at the YM planting was caused by repeated deer, Odocoileus virginianus, browsing and competition from hay-scented fern, Dennstaedtia punctilobula. Additionally, seedlings at the DBNF study were repeatedly defoliated by Craesus castaneae, chestnut sawfly, during the first growing season (chapter 3). Seedlings with larger root collar diameters at planting demonstrated greater survival and growth in the DBNF study while seedlings larger in height and RCD added less growth and were more likely to die in the YM study, likely due to the high deer population and dense understory competition. These results indicate that silvicultural treatments that create high-light environments are ideal for chestnut, however the species can establish successfully under a variety of light conditions, from low light [10% photosynthetically active radiation (PAR)] to high light (65% PAR). Ink disease will present a formidable obstacle to chestnut reintroduction efforts in the south, while northern efforts will be challenged by deer browsing due to overpopulated deer herds.
596

Plant community dynamics in remnant and restored Willamette Valley wetland prairies /

Schwindt, Rachel A. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 73-81). Also available on the World Wide Web.
597

Effectiveness of stand-scale forest restoration, Siskiyou Mountains, Oregon

Lininger, Jay Charles. January 2006 (has links)
"Professional paper presented in partial fulfillment of the requirements for the degree of Master of Science in Environmental Studies, the University of Montana, Missoula, MT, fall 2006." / Title from PDF t.p. (viewed on Feb. 26, 2007). Includes bibliographical references (p. 77-90).
598

Restoration criteria on dolomite quarries on "Sierra de Mijas" mountain range

Jimenez, Alberto Jr January 2007 (has links)
There are many dolomitic outcrops at Rondean sector (into the biogeographical Betic Province). Most of them, involve floral richness and vegetal endemic species due to its calcareous origin. These diverse organisms build peculiar plant communities. They can survive in extreme conditions as drought and high levels of Mg2+ cation. Many studies pronounce that these communities are unique, so they have to be conserved, and some of these plant communities are in the Habitats Directive 92/43 EC. 38% of the dolomitic outcrops can be affected by mining processes. Those particularly affected are dolomitic outcrops located in the mountains range of “Sierra Blanca” and “Sierra de Mijas”. Nowadays, there are 21 quarries in these mountains and they occupy more than 409 Ha. We have studied 11 dolomite quarries and surroundings on “Sierra de Mijas”. There is one vegetation serie on these areas (Rhamno oleoidis-Querco rotundifoliae sigmetum. Dolomitic section), knowing the plant communities we could draw with a Geographical Information System (GIS) the polygons where they are. And using the modified Botanic Value Index equation (Nieto et al., 1999) we could calculate the botanical value of these polygons. After that, we could establish a classification of the study area from the point of view of conservation interest, and we could set up new restoration criteria on these lands. We have found that approximately the 53 % of the studied area has a high botanic value. There are many endemic taxa in the studied area and 4 species exclusive of the “Sierra de Mijas” mountain range. 90 % of the present communities are included in the Habitats Directive 92/43 CE, and three of the communities are exclusive of the studied area. This is the reason why these quarries have to be restored with a sustainable criteria. Current restoration plans try to reforest with the climax vegetation (Quercus rotundifolia) or different species of pines (used in several previous reforestations). However, to restore a quarry these plans should include, in addition, other factors such as soil depth, structure of vegetal communities, botanic value, etc. And the Reforest Models of Valle (2004) propose sustainable restoration that could be usefull in the dolomite quarries of “Sierra de Mijas” mountain range.
599

The effects of herbivory, competition, and disturbance on island meadows

Gonzales, Emily Kristianne 05 1900 (has links)
It is an unresolved paradox that non-native species are successful in novel environments whereas native species, presumably adapted to that environment, decline. This knowledge gap has persisted because third party processes in invasion ecology have been overlooked. Ungulate densities are increasing due to the eradication of predators and landscape change and I asked how herbivory and invasion might interact to cause declines of native species. In Garry oak meadows, Canada’s most endangered ecosystem, native forbs have declined relative to non-native grasses and I tested the facilitatory role of herbivory in that degradation. My investigations, novel to the field, were conducted on islands spanning the Canada-US border. Islands served as natural experimental units in a mensurative study of abundance patterns in seven plant groups and 15 focal species along gradients of herbivory, biogeography, soil depth, and human activities. Increasing ungulate densities were related to declines in abundances of native forbs, and increasing abundances of non-native annual grasses. These regional patterns were upheld by two plot-based, 2x2 factorial experiments that contrasted the fitness of native species under manipulations of herbivory and competition for light. Specifically, I showed that ungulates limited the establishment, growth, survival and reproduction of seedlings and transplanted native forbs and shrubs and that competition from non-native species had little effect. I also calculated forage selectivity indices and tested the efficacy of fencing and cutting to reduce competition, for the restoration of native community biomass. Non-native annual grasses were rarely browsed and increased with increasing ungulate density. Non-native perennial grasses declined with herbivory, however, their regional abundances were unaffected by ungulate density despite being preferentially foraged. That non-native annual and perennial grasses differed in their responses to herbivory has consequences for restoration and illustrates the challenge of developing a comprehensive theory of invasion. Reducing ungulates, necessary for the recovery of native forbs, also benefits non-native perennial grasses and therefore their removal speed recovery of Garry oak meadows. Despite advances in invasion ecology, scientists and managers are disconnected and research is rarely implemented. I conclude by proposing seven solutions to facilitate the integration of science into management.
600

Take Me to the River: Revitalizing LA's Lost Monument

Childs, Erin 01 May 2012 (has links)
The tale of South Korea's Cheonggyecheon River is one to warm an urban environmentalist's heart. Cheonggyecheon runs through the center of Seoul, a bustling metropolis of ten million that has been the capital of Korea since the 14th century. The Japanese were the first to sacrice Cheonggyecheon on the altar of urbanization, turning the River into a sewage system during their 35 year occupation between 1910 and 1945. Already thusvdegraded, it was easy for later administrations to eventually completely cover the river with the Cheonggye Road and Cheonggye Elevated Highway between 1958 and 1976. Cheonggyecheon became an exemplar of the expendability of urban environments in the face of modernization and economic growth, particularly the need for transportation in a quickly developing city. In the early 1990s it was discovered that extensive repair would be necessary to maintain the Highway, and with heavy political leadership of Mayoral Candidate Myung-Bak Lee, now the president of South Korea, the decision was made to restore the river rather than repair the road (Park, 2006).

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