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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.
41

Integrated water demand management for local water governance

Du Plessis, J. A. 12 1900 (has links)
Thesis (PhD (Public Management and Planning))--University of Stellenbosch, 2010. / Please refer to full text for abstract
42

The value of agri-environment schemes and farm woodland for bats and nocturnal insects

Fuentes-Montemayor, Elisa January 2011 (has links)
Many bat species in Europe have undergone severe population declines during the last century and one of the driving causes is believed to be the loss of roosting and foraging habitat through agricultural expansion and intensification. Modern agricultural practices have also had strong negative effects on many insect groups, such as moths, which are important components of the diets of many bat species. Agri-environment schemes (AES) have been introduced in many countries as an attempt to counteract the negative effects of intensive agriculture on biodiversity by providing financial incentives for farmers to adopt environmentally-sensitive agricultural practices. AES are potentially beneficial to bats and nocturnal insects, but the response of these taxa to their implementation had not been assessed prior to this study. Here, the potential benefits (or otherwise) that bats and their insect prey species gain from the implementation of certain AES management prescriptions was assessed using ultrasonic detectors (to assess bat activity levels) and heath light traps (to quantify nocturnal insect abundance) at 18 pairs of AES and conventionally-managed farms. In addition, the influence of the surrounding landscape on bats and insects was quantified to evaluate the relevance of a landscape-scale management approach for the conservation of these taxa. Some of the AES prescriptions assessed in this study benefited moths (and are potentially beneficial for moth-eating bats), but not Pipistrelle bats nor their insect prey. The most important factors associated with bat activity on farmland were metrics related to woodland configuration in the surrounding landscape, which suggests that conservation efforts for bats should focus on the creation and management of this habitat. Currently, some AES prescriptions aim to increase the amount and quality of woodland on agricultural land, but little is known about how woodland character relates to bat abundance and insect prey availability; therefore, recommendations for woodland creation and management rarely consider the requirements of foraging bats. Here, the influence of woodland character (e.g. vegetation structure and patch configuration) on bats and nocturnal insects was assessed. Vegetation surveys were conducted and Geographic Information Systems (GIS) were used to quantify the vegetation character and spatial configuration of 34 woodland patches within farmland. Two complementary methods (acoustic monitoring and bat trapping assisted by an acoustic lure) were used to assess the influence of woodland vegetation character, patch configuration and the surrounding landscape on bat populations. Nocturnal insect abundance at each site was assessed using heath light traps. Data presented here demonstrate that bats show species-specific associations with woodland vegetation structure and patch configuration; patterns of higher bat abundance and activity at small and isolated woodland patches suggest that bats utilize this habitat more intensively in landscapes where woodland is scarce. This thesis also shows that moths are strongly influenced by woodland character; in general, large woodland patches of compact shapes, composed of a large number of native tree species and a dense understory cover, and located close to other woodlands were associated with high moth abundance and species richness (and are potentially valuable for moth-eating bats). Other nocturnal insects (mainly Diptera) were not influenced by woodland character. This study also shows that bats and nocturnal insects are influenced by the landscape context; moths are mainly influenced by the extent of semi-natural environment (such as rough grassland and scrub) within small spatial scales (within 250 m; although effects of woodland extent were detected at larger spatial scales for woodland specialists moths). Bats are mainly influenced by woodland-related landscape metrics. Some bat species are influenced by the surrounding landscape at large spatial scales (within 3 km) and would benefit from woodland creation and management at a wide-landscape-scale. The findings presented in this thesis have important management implications for the design of agri-environment schemes. A list of management recommendations to optimize the benefits that bats and nocturnal insects gain from these schemes is presented in the final section.
43

Riverscape-mediated effects of introduced trout on non-diadromous galaxiid fishes in New Zealand

Woodford, Darragh J. January 2009 (has links)
The impact of invasive predators on native prey may depend on the availability and distribution of invader-free refugia across landscapes, if predators create demographic ‘sink’ populations in invaded patches, giving rise to source-sink dynamics in prey populations. Propagule pressure of immigrants dispersing from refugia (or sources) may consequently drive persistence in sink habitat, affecting predator-prey co-existence across the landscape. I studied whether introduced brown (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) create source-sink structuring in two native galaxiid fish species (Galaxias vulgaris and G. paucispondylus) in the rivers of the central South Island, New Zealand, and whether such dynamics affected the distributions of either species across river networks or “riverscapes”. Young-of-the-year (YOY) G. vulgaris recruitment was rare in trout-invaded streams and consistently high in trout-free streams. Thus, trout-free reaches appeared to act as sources in a river network, while the majority of the trout-invaded riverscape was a demographic sink (i.e., no local recruitment occurred). Surveys of YOY G. paucispondylus did not reveal trout-induced source-sink dynamics, although mesocosm predation experiments suggested both species were highly vulnerable to predation by large trout. Galaxias paucispondylus recruitment was highest in intermittently flowing streams that were marginal habitats for trout, suggesting indirect interactions between trout and habitat affect G. paucispondylus distribution. Network configuration of trout-free source populations affected the distribution of G. vulgaris, as galaxiids were excluded from small streams with high bed stability that were far from sources. The interaction between propagule pressure and habitat gradients in mediating effects of trout on G. vulgaris distributions indicates habitat characteristics affect predator-prey interactions in a spatially explicit manner. Furthermore, the outcome of predator-prey interactions should be able to be modelled using habitat data alone if habitat consistently mediates predator impacts. I developed a GIS-based spatial model to predict where trout would exclude G. vulgaris in river networks, based on stream size and distance to galaxiid source populations. The model was tested in three different riverscapes using fish occurrence patterns obtained from electrofishing surveys, and successfully predicted G. vulgaris exclusion by trout. This further demonstrates the importance of habitat configuration in driving interspecific interactions at the landscape scale. These findings suggest removing trout from small, stable tributaries to create new demographic sources could improve overall persistence of G. vulgaris across trout-invaded riverscapes. The galaxiid exclusion model should also be used to detect undiscovered trout-free source populations, and to aid in selecting streams for restoration of galaxiid populations through trout eradication.
44

Fruit-feeding butterfly assemblages at Dlinza and Entumeni Nature Reserves, KwaZulu-Natal : a quantitative biodiversity study / cWayne S. Forrester.

Forrester, Wayne Steven January 2011 (has links)
Fruit-feeding butterfly assemblages at two indigenous forests in KwaZulu-Natal, the Dlinza and Entumeni forests were studied with baited traps during a year cycle June 2008-May 2009 and an additional March-May 2010 (autumn) survey. A total of 2801 butterflies were trapped, which consisted of 28 species, representing five subfamilies of the Nymphalidae, with the most abundant and species rich subfamily being Charaxinae. Higher than expected abundances and numbers of species trapped during the present study, though significantly lower than some tropical areas in Africa, demonstrate that this technique of quantifying assemblages with baited-traps are effective in forests of KwaZulu-Natal, South Africa and should be included in future butterfly assessments. During a mark-release-recapture survey, very few fruit-feeding butterflies were recaptured, with no observed dispersal events between the two forests. A high turnover of fruit-feeding butterfly populations reflects adequacy of habitat quality and size at both the forests for the conservation of this guild of butterfly fauna. Season had a marked effect on butterfly assemblages with optimal times of the year emerging as autumn and winter, when butterfly abundance and species richness were highest. Abundance and diversity (Shannon index) at the smaller Dlinza forest were marginally higher or at least very similar to that of the larger Entumeni forest. Higher species richness (d) was recorded at the larger Entumeni forest. A greater number of individuals and higher number of species were trapped at both forest edges in comparison to forest interior (clearings). Species richness (d) and diversity (Shannon index) at Dlinza forest were higher at the interior (forest clearings) compared to that of the Dlinza forest edge. In contrast higher species richness and diversity (Shannon index) were recorded at the Entumeni edge if compared to the Entumeni interior. Highest species richness (d) was consistently recorded at the Entumeni forest edge. Similarity between the species compositions of both forests was high. The Entumeni forest are imbedded in a larger zone of natural grassland in contrast to the Dlinza forest which is partly located in an urban setting with small or absent grassland buffer zones. Altitudinal differences between these forests had lesser influence on the fruit-feeding butterfly assemblages whilst the closer urban edge at the Dlinza forest appears to contribute to a negative impact on the species richness at the forest margin. Recommendations to the conservation management of the Dlinza and Entumeni forests, stemming from this study, include conserving small forest remnants as part of stepping stone corridors between the forests, eradication of alien invasive plant species, conserving grassland buffer zones in which the forests are embedded and caution to any future developments in this unique area. Awareness to preserve and understand the wealth of indigenous smaller fauna, which are dependent on these magnificent forests, is to be promoted. / Thesis (Master of Environmental Sciences)--North-West University, Potchefstroom Campus, 2012.
45

Fruit-feeding butterfly assemblages at Dlinza and Entumeni Nature Reserves, KwaZulu-Natal : a quantitative biodiversity study / cWayne S. Forrester.

Forrester, Wayne Steven January 2011 (has links)
Fruit-feeding butterfly assemblages at two indigenous forests in KwaZulu-Natal, the Dlinza and Entumeni forests were studied with baited traps during a year cycle June 2008-May 2009 and an additional March-May 2010 (autumn) survey. A total of 2801 butterflies were trapped, which consisted of 28 species, representing five subfamilies of the Nymphalidae, with the most abundant and species rich subfamily being Charaxinae. Higher than expected abundances and numbers of species trapped during the present study, though significantly lower than some tropical areas in Africa, demonstrate that this technique of quantifying assemblages with baited-traps are effective in forests of KwaZulu-Natal, South Africa and should be included in future butterfly assessments. During a mark-release-recapture survey, very few fruit-feeding butterflies were recaptured, with no observed dispersal events between the two forests. A high turnover of fruit-feeding butterfly populations reflects adequacy of habitat quality and size at both the forests for the conservation of this guild of butterfly fauna. Season had a marked effect on butterfly assemblages with optimal times of the year emerging as autumn and winter, when butterfly abundance and species richness were highest. Abundance and diversity (Shannon index) at the smaller Dlinza forest were marginally higher or at least very similar to that of the larger Entumeni forest. Higher species richness (d) was recorded at the larger Entumeni forest. A greater number of individuals and higher number of species were trapped at both forest edges in comparison to forest interior (clearings). Species richness (d) and diversity (Shannon index) at Dlinza forest were higher at the interior (forest clearings) compared to that of the Dlinza forest edge. In contrast higher species richness and diversity (Shannon index) were recorded at the Entumeni edge if compared to the Entumeni interior. Highest species richness (d) was consistently recorded at the Entumeni forest edge. Similarity between the species compositions of both forests was high. The Entumeni forest are imbedded in a larger zone of natural grassland in contrast to the Dlinza forest which is partly located in an urban setting with small or absent grassland buffer zones. Altitudinal differences between these forests had lesser influence on the fruit-feeding butterfly assemblages whilst the closer urban edge at the Dlinza forest appears to contribute to a negative impact on the species richness at the forest margin. Recommendations to the conservation management of the Dlinza and Entumeni forests, stemming from this study, include conserving small forest remnants as part of stepping stone corridors between the forests, eradication of alien invasive plant species, conserving grassland buffer zones in which the forests are embedded and caution to any future developments in this unique area. Awareness to preserve and understand the wealth of indigenous smaller fauna, which are dependent on these magnificent forests, is to be promoted. / Thesis (Master of Environmental Sciences)--North-West University, Potchefstroom Campus, 2012.
46

Riverscape-mediated effects of introduced trout on non-diadromous galaxiid fishes in New Zealand

Woodford, Darragh J. January 2009 (has links)
The impact of invasive predators on native prey may depend on the availability and distribution of invader-free refugia across landscapes, if predators create demographic ‘sink’ populations in invaded patches, giving rise to source-sink dynamics in prey populations. Propagule pressure of immigrants dispersing from refugia (or sources) may consequently drive persistence in sink habitat, affecting predator-prey co-existence across the landscape. I studied whether introduced brown (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) create source-sink structuring in two native galaxiid fish species (Galaxias vulgaris and G. paucispondylus) in the rivers of the central South Island, New Zealand, and whether such dynamics affected the distributions of either species across river networks or “riverscapes”. Young-of-the-year (YOY) G. vulgaris recruitment was rare in trout-invaded streams and consistently high in trout-free streams. Thus, trout-free reaches appeared to act as sources in a river network, while the majority of the trout-invaded riverscape was a demographic sink (i.e., no local recruitment occurred). Surveys of YOY G. paucispondylus did not reveal trout-induced source-sink dynamics, although mesocosm predation experiments suggested both species were highly vulnerable to predation by large trout. Galaxias paucispondylus recruitment was highest in intermittently flowing streams that were marginal habitats for trout, suggesting indirect interactions between trout and habitat affect G. paucispondylus distribution. Network configuration of trout-free source populations affected the distribution of G. vulgaris, as galaxiids were excluded from small streams with high bed stability that were far from sources. The interaction between propagule pressure and habitat gradients in mediating effects of trout on G. vulgaris distributions indicates habitat characteristics affect predator-prey interactions in a spatially explicit manner. Furthermore, the outcome of predator-prey interactions should be able to be modelled using habitat data alone if habitat consistently mediates predator impacts. I developed a GIS-based spatial model to predict where trout would exclude G. vulgaris in river networks, based on stream size and distance to galaxiid source populations. The model was tested in three different riverscapes using fish occurrence patterns obtained from electrofishing surveys, and successfully predicted G. vulgaris exclusion by trout. This further demonstrates the importance of habitat configuration in driving interspecific interactions at the landscape scale. These findings suggest removing trout from small, stable tributaries to create new demographic sources could improve overall persistence of G. vulgaris across trout-invaded riverscapes. The galaxiid exclusion model should also be used to detect undiscovered trout-free source populations, and to aid in selecting streams for restoration of galaxiid populations through trout eradication.
47

Stanovištní vazba nočních motýlů (Lepidoptera: Macrolepidoptera) ve stanovištně pestré přírodní rezervaci (NPR Koda, Český kras) / Habitat association of moths (Lepidoptera: Macrolepidoptera) in a structurarly diverse nature reserve (Koda National Nature Reserve, Cesky Kras)

ZÁVITKOVSKÁ, Lenka January 2011 (has links)
Based on light trapping carried out in 2010, I studied moth communities of the Koda National nature reserve, part of Český kras landscape protected area, in order to compare moth communities inhabiting major biotope types within the reserve. The obtained material consisted of 295 species in 4455 individuals. Steppe enclaves hosted more species than overgrown coppices and beech-dominated high forests. Ordination analyses distinguished between steppe and forest biotopes. Steppe catches differed from forest catches in habitat associations of constituent species (more species of grassland habitats), whereas the two forest types did not differ in this. Identical patterns applied for all moths analysed together and for analyses restricted to Geometridae and Noctuidae moths. Steppic enclaves represent the most valuable sites within the Koda reserve.
48

Ecological and socio-economic effects of industrial oil palm plantations in Southwest Cameroon

Kupsch, Denis 30 September 2019 (has links)
No description available.
49

Three Essays on Watershed Modeling, Value of Water Quality and Optimization of Conservation Management

Surendran Nair, Sujithkumar 15 January 2010 (has links)
No description available.
50

THE BEDOUIN KNOW: USING LOCAL KNOWLEDGE TO UNDERSTAND THE EFFECTS OF DEVELOPMENT AT THE WADI RUM PROTECTED AREA IN SOUTHERN JORDAN

Strachan, Laura M. 10 1900 (has links)
<p>There are two central themes to this thesis. Firstly, it shows how the adoption of people-centered and greening development paradigms, designed to improve mainstream development problems of the late 20<sup>th</sup> century, continue to produce unsatisfactory and unsustainable results for intended beneficiaries in the 21<sup>st</sup> century. Secondly, it shows how the “intended beneficiaries” use their experiences and their knowledge of the development processes to analyze, explain and voice why it has not worked for them. Their <em>local knowledge</em> illustrates how beneficiaries continue to remain on the “outside” or peripheral to development instead of being equal partners as the people-centered discourse claims.</p> <p>This thesis reviews the development of the Wadi Rum Protected Area (WRPA) in southern Jordan. This development fostered both conservation and tourism projects to assist members of the seven local Bedouin communities or clans whose historical rangelands constitute the protected area. Four significant development decisions and projects are examined to better understand how this development functioned. Many Bedouin commentaries and those of some non-Bedouin involved in the projects provide social, economic and environmental assessments of the protected area's progress over a ten year continuum. What emerges is a nuanced awareness of how the WRPA has not achieved its stated goals or the benefits promised to the Bedouin, but did support other developers', lenders' and government objectives. Bedouin knowledge also highlights how “development” has contributed to a near dissolution of their control over what had been their tourism industry, how it has usurped their control of their lands and villages, how the project has created greater divisiveness between and within the clans and how it has come to support the growth of tourism over environmental protection. In general, the development of the Wadi Rum Protected Area has not achieved its people-centered and green goals.</p> / Doctor of Philosophy (PhD)

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