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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.
11

The health-related microbial quality of drinking water from ground tanks, standpipes and community tankers at source and point-of-use in eThekwini Municipality : implications of storage containers, household demographics, socio-economic issues, hygiene and sanitation practices on drinking water quality and health.

Singh, Urisha. January 2009 (has links)
The aim of this study was to investigate the microbiological quality of drinking water at the source (taps at eThekwini laboratories, standpipes and mobile community tankers) and corresponding point-of-use (storage containers and ground tanks) supplied to peri-urban areas in Durban by eThekwini Municipality. It also aimed to identify factors associated with deterioration in water quality such as storage of water, household demographics, hygiene and sanitation practices. In order to determine the microbial quality of drinking water, the pour plate method (for enumeration of heterotrophic organisms) and the membrane filtration technique (for total coliforms and E. coli enumeration) were used. Conductivity, turbidity, pH and total and residual chlorine levels of drinking water were measured. Microbial and physico-chemical data was collated and statistically analysed with epidemiological data from an associated study to determine the link between microbial quality of drinking water, household demographics, health outcomes, socio-economic status, hygiene and sanitation practices. Findings showed that all point-of-use water was unsafe for human consumption as a result of either poor source water quality, in the case of standpipes, and microbial contamination at the point-of-use, in the case of ground tanks and community tankers. The latter could be attributed to unsanitary environments, poor hygiene practices or poor wateruse behaviour. Households which included children aged 0-5 years and in which open-top containers were used for water storage had the highest rates of diarrhoea and vomiting. Water from ground tanks had the best microbial quality but people in households using this water presented with the highest rate of diarrhoea. Therefore provision of microbially safe drinking water will not reduce the rate of health outcomes if addressed in isolation. In order to reduce water-associated illness, provision of safe and adequate amounts of water, hygiene and sanitation education and education on water-use behaviour should be provided as a package. The provision of improved water delivery systems does not ensure that drinking water is safe for human consumption. Measures, such as point-of-use water treatment should be considered to ensure that drinking water provided at the source and point-of-use is microbially safe for human consumption. / Thesis (M.Sc.)-University of KwaZulu-Natal, 2009.
12

Lion spatial socio-ecology : the effect of habitat on lion group dynamics.

Donkin, Deborah Anne. January 2000 (has links)
Lions are social, territorial animals that form prides of 2-18 individuals and hold territories ranging in size from 20 to 500 square km. My aim was to investigate the effect of ecological processes on lion spatial demography, specifically to determine the effect of habitat structure, prey availability, and rainfall (predictability and variability) on lion group dynamics. I worked with an extensive database of lion observations (approximately -+7000 over 29 years) from the Kruger National Park that had been recorded on monthly predator returns and in ranger diaries. I used the hypothesis of ideal free distribution to explain group dynamics across four physical habitat structures, namely, thickets, woodlands, mountainous areas and open tree savanna. There were larger groups of adults and more sightings than expected in the open tree savanna, while subadult and cub group sizes peaked in the woodlands. Using the resource dispersion hypothesis (RDH) as a base, I investigated lion group dynamics in relation to prey availability, I found agreement with the RDH, in that larger groups formed where their favoured prey species were in greatest abundance. Exclusively adult male and exclusively adult female group sizes increased with increasing buffalo abundance, while groups of adult males and adult females in mixed groups increased with increasing impala abundance. I used the mechanism of risk sensitive foraging to explain the influence of rainfall on lion group dynamics. While group dynamics did not differ significantly across averaged mean annual rainfall regions or across seasons, it did differ between variability regions and between two years of extreme rainfall. The lions exhibited risk-prone behaviour across variability regions, forming larger groups in more variable environments. Finally, I combined the three factors to determine the relative importance of each in determining lion group dynamics across seasons. Wildebeest were important to adult female group dynamics, impala and buffalo to adult males, while buffalo abundance influenced functional group size. In the wet season, larger functional groups occurred in the areas of medium rainfall variability regardless of buffalo abundance. In the dry season, more groups of females than solitary females occurred in more variable environments with this trend reversed for males. / Thesis (M.Sc.)-University of Natal, Durban, 2000.
13

Aspects of the ecology of sandy beaches along Durban's urbanised coastline.

Govender, Natasha. January 2009 (has links)
Urban sandy beaches are the primary focus of numerous pressures. Among these are the disruption of sand budgets because of an increasing demand for coastal infrastructure, pollution from landward sources, and recreation and the associated stressors such as trampling and off-road vehicles. More recently, climate change and the manifestations thereof, such as sea-level rise and increased storminess have added to the suite of threats to sandy beach ecosystems. Despite being important natural and economic resources these urban systems have not received adequate research attention and, consequently, the management of sandy beaches has been based on ecologically unsustainably principles. The aims of this study were to provide baseline biodiversity information of urban beaches along the Durban coastline, South Africa, as a step toward the application of improved ecological management procedures for metropolitan beach ecosystems. Macro- and meiofaunal communities of 15 representative beaches along the Durban coastline were quantitatively surveyed using standard sandy beach sampling protocols. This study showed that Durban’s beaches, despite being highly urbanised, harbour rich and abundant faunal communities. This is contrary to previous findings that reported a paucity of life on Durban beaches. A total of 23 macrofauna taxa were identified, with the dissipative Battery Beach having highest diversity with 13 macrofaunal species. La Lucia, a reflective beach, had the highest macrofaunal abundance and was the second most diverse beach, thus departing from global trends that report a poor macrofaunal community of reflective beaches. Twenty higher-level meiofauna taxa were recorded in this study and it was found that meiofauna abundance showed a significant and positive relationship with beach width. Because of the coarse taxonomic resolution, meiofauna diversity may likely be much greater than that recorded in this study. The conventional view that sandy beaches are resilient to exploitation was questioned when it was found that meiofauna assemblages were significantly and negatively impacted by stormwater outlets on two of the sampled beaches, possibly through freshwater intrusion or erosional effects. This raises questions regarding the functioning of beach ecosystems, and the services they provide, when faced with anthropogenic stressors that impact faunal communities. This snapshot survey of aspects of the ecology of Durban’s sandy beaches has provided much needed baseline data for this coastline. These data will be used in conjunction with other available data toward the development of a fine scale systematic conservation plan for Durban to enable the prioritisation of conservation and management efforts. The use of these data will also facilitate the development of guidelines for the integrated ecological management of urban sandy beach ecosystems. / Thesis (M.Sc.)-University of KwaZulu-Natal, 2009.
14

The effect of wastewater works on foraging behaviour and metal content of Neoromicia nana (Family : Vespertilionidae)

Naidoo, Samantha. January 2011 (has links)
Anthropogenic disturbance from urbanization has introduced a range of contaminants into freshwater ecosystems. Wastewater Treatment Works (WWTW) in particular, deposit effluent with high metal concentrations directly into rivers. These pollutants may affect river biota directly or through modifications to habitat and prey. Therefore, the impact of metal pollution through a food chain should be evident in high trophic level predators such as Neoromicia nana. N. nana is a small, insect-eating bat that occurs in forest and riparian habitats in Africa. Most importantly, it is an urban exploiter, i.e. a species that takes advantage of anthropogenic food and habitat resources. I investigated the foraging behaviour and metal content of N. nana at wastewater-polluted sites (WWTW sludge tanks and sites downstream of wastewater discharge into the rivers) and unpolluted sites (sites upstream of wastewater discharge) at three urban rivers in Durban, South Africa, during winter and summer. To assess water quality, I determined cadmium, copper, chromium, iron, nickel, zinc and lead concentrations using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). To investigate the foraging behaviour of N. nana, I quantified relative N. nana abundance, and feeding activity from recorded echolocation calls. Using ICP-OES, I quantified metal concentrations in three tissues (liver, kidney and muscle). My results show that concentrations of most metals were generally lowest upstream, intermediate at downstream sites and highest at the tanks. The relative abundance and feeding activity of N. nana were significantly higher at wastewater-polluted sites than at upstream sites, despite there being significantly more insect orders upstream. However, pollution-tolerant Chironomidae (Diptera), were significantly more abundant at wastewater-polluted sites. Indeed, at wastewater-polluted sites, Diptera represented the highest percentage of insects in the diet of N. nana. Essential metals (copper, zinc and iron) were detected in all tissue samples of N. nana. In contrast, the toxic metals cadmium, chromium and nickel were present in tissue of bats only at wastewater-polluted sites (except one upstream occurrence of cadmium). This suggests that these metals may accumulate in tissue through the ingestion of pollutant-exposed prey. Thus, metal pollution from WWTWs affects not only water quality of rivers, but also the diversity of resident aquatic insects and ultimately the ecology of N. nana populations, which may pose serious long-term health risks for these top predators. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2011.
15

Monitoring ground-level ozone and nitrogen dioxide in parts of KwaZulu-Natal and Mpumalanga (South Africa) by means of chemical and biological techniques.

Blair, Sharon Ann. January 1998 (has links)
Surface ozone (O3) is one of the most toxic and abundant air pollutants. It has deleterious effects on human and animal respiration processes, and adversely affects plants. Four sites were selected for monitoring ambient O3 in the Durban metropolitan area: Botanic Gardens, University of Natal (UND), top of Kloof Gorge, and Mooi River. At each site tobacco Bel-W3 bioindicators, and NO2 and O3 passive diffusion tubes were placed. An O3 analyser (Dasibi 1108) was situated at the UND site. Monitoring was carried out for four weeks during summer, autumn and winter at each site, and during spring at the UND site. Two weeks of data from the diffusion tubes were collected during spring, from the Nelspruit area, Mpumalanga. Ozone concentrations measured with the Dasibi at the UND site were low in comparison to other urban-industrial areas in the world, with hourly values falling between 5ppb and 10 ppb. The highest hourly mean maximum recorded was 40ppb. A general spring/winter maximum and summer minimum was observed. This is typical of subtropical locations, where subsidence in prevailing anticyclonic circulation occurs. Diurnal characteristics included early morning minima and maxima at 12h00 in spring and summer, and maxima approximately two hours later in autumn and winter. This pattern was typical of that found in polluted environments, the magnitude, however, being lower. An unusual secondary nocturnal peak occurred during autumn, winter and spring. This could have been due to the long-range transport of relatively O3-rich air from a non-urban, high altitude inland area. Ozone concentrations were not strongly influenced by meteorological variables. Diffusion tube data indicated low O3, however, the coefficients of variation were high, implying a lack of precision in this technique. This technique would have to be improved before data obtained could be regarded as valid. Nitrogen dioxide, NO2, one of the precursors to O3, was monitored using diffusion tubes at the same sites. Concentrations were highest closer to the city centre, the highest concentration being 31ppb in autumn. In the Mpumalanga study, NO2 concentrations were higher in the city of Nelspruit than the surrounding areas. No significant differences were found in the O3 concentrations between the Mpumalanga sites. The tobacco plants showed the highest visible leaf injury in winter, corresponding with the higher Dasibi values, but there were no significant differences between the sites, and no significant differences in chlorophyll contents between the sites. In this study, O3-induced injury occurred below the previously established threshold of 40ppb. / Thesis (M.Sc.)-University of Natal, Durban, 1998.
16

Patterns and processes of rodent and shrew assemblages in the Savanna Biome of KwaZulu-Natal, South Africa.

Rautenbach, Anita. 05 November 2013 (has links)
The identification of non-random species composition patterns predicted by assembly rules is a central theme in community ecology. Based on life history characteristics, species composition patterns of rodents and shrews should be consistent with predictions from nestedness rather than competition hypotheses. This study investigated the seasonal changes in rodent and shrew assemblages in eleven savanna vegetation types in a protected reserve in South Africa. Rodents and shrews were sampled between 2009 and 2010 at Phinda Private Game Reserve (PPGR), KwaZulu-Natal. Sample-based rarefaction curves showed that rodent and shrew abundance and richness varied among seasons and vegetation types. Species richness estimators indicated that inventories for rodents (80%) and shrews (100%) were fairly complete. Null-model analyses found no evidence that species co-occurrence patterns in the reserve were non-random with respect to predictions from Diamond’s Assembly rules, niche limitation hypothesis and nestedness hypothesis. I also investigated seasonal changes in species richness and abundance of rodent and shrew assemblages on cattle, pineapple and former cattle farms surrounding PPGR, and used cluster analyses to compare the species composition of rodents and shrews at farm and PPGR study sites. Small mammal assemblages exhibited a heterogeneous distribution and species composition patterns changed between seasons. Sample-based rarefaction curves showed that rodent and shrew abundance and richness varied among seasons and study sites. Species richness estimators indicated that inventories for the rodents (91%) and shrews (100%) on the farms were essentially complete. Rodent and shrew species composition patterns did not group study sites according to land use, nor could species composition patterns be explained by vegetation characteristics. My results suggest that complex biotic and abiotic processes other than competition, nestedness, land use and vegetation characteristics operate at different spatial and temporal scales to structure rodent and shrew assemblages. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2013.
17

The biology of and fishery for king mackerel, Scomberomorus commerson (Scombridae), along the southern Mozambique and KwaZulu-Natal coast.

Lee, Brendon. January 2013 (has links)
The king mackerel, Scomberomorus commerson, is an epipelagic, schooling predator supporting significant commercial, artisanal and recreational fisheries throughout the coastal waters of its Indo-Pacific distribution. Despite the importance of the species within the South West Indian Ocean, little research has been undertaken on its biology and fisheries on a regional basis over the past 20 years. The aim of this study was to evaluate the fishery and biology of S. commerson in the South West Indian Ocean and identify gaps in information required to ensure its effective management. Catch and effort data for the KwaZulu-Natal recreational S. commerson linefishery were extracted from the National Marine Linefish System in order to assess spatial and temporal trends in abundance. Generalized linear models utilizing the delta method were used to quantify the effect of year, month, region, rainfall and sea surface temperature on CPUE. Biological samples of S. commerson were collected monthly from within KwaZulu-Natal and southern Mozambique. Samples were analysed using standard biological techniques. A per-recruit analysis was conducted using the biological parameters from KwaZulu-Natal and southern Mozambique in order to assess the status of the S. commerson stock and provide management recommendations based on the findings. Long-term trends in CPUE were cyclic in nature with peaks and troughs appearing to be independent of fishing pressure. Seasonal abundance reflects the south-north migration into KwaZulu-Natal waters with short term environmental factors such as sea surface temperature significantly affecting spatial and temporal extent of the migration among regions. S. commerson spawn in southern Mozambique waters from September to January (spring-summer) with males maturing at a smaller size (65.2cm FL) compared to females (82.3cm FL). The overall sex ratio (M: F) was 1:1.36 possibly as a result of linefishing selecting for faster growing, larger females. S. commerson in KwaZulu- Natal and southern Mozambique display rapid growth over the first two years before slowing down considerably after maturity is reached. Females grow faster and live longer compared to males dominating the older and larger size classes, and attaining a maximum observed age of 14 years, although fish probably live up to 20 years. Natural mortality rate was estimated at 0.27 yearˉ¹. Fishing mortality for the combined region was 0.21 yearˉ¹. The per-recruit analyses for the KwaZulu-Natal and southern Mozambique indicated that the fishery is being optimally exploited with a current spawner biomass per recruit at 49% of its theoretical pristine level. Uncertainty with regards to the fishing pressure in southern Mozambique as a result of illegal fishing and fishing sectors targeting smaller S. commerson is a cause for concern. The current recreational daily bag limit of 10 fish.person.dayˉ¹ is considered excessive by many stakeholders. Given the similarity of the recreational ski-boat fishery in southern Mozambique, a reduction in the DBL of S. commerson to five fish pppd in both KwaZulu-Natal and southern Mozambique waters would benefit recreational fishers by more equitable sharing of the catch and potentially by reducing fishing mortality at times when the fish are aggregated and vulnerable to high catch rates. A reduced DBL limit would also reduce the incentive of individual anglers to make large catches and to sell their fish illegally. / M.Sc. University of KwaZulu-Natal, Durban 2013.
18

The development of an open space system for the Queensburgh municipal area.

Seppings, Kerry Ann. January 1994 (has links)
This project was conducted with the view of extending the Durban Municipal Open Space System into surrounding municipalities. It was aimed at adopting a holistic approach to nature conservation by providing for the needs of the current human population whilst ensuring the long term survival of representative natural biota of the area. A preliminary study was conducted to: provide a basis for a more detailed vegetation survey; to assess the current public open space areas and to determine the land use history of the area. The vegetation was categorised into 14 community types and mapped to provide the basis for more detailed sampling. A survey of public open spaces revealed that most of the public parks were not providing for the needs of the local residents and that nature reserves and sports fields were more popular than conventional public parks. The land use history study revealed that the study area has been utilised for: cultivation; grazing; market gardening and more recently residential and industrial development purposes. A vegetation survey using phytosociological methods revealed that the vegetation in Queensburgh was dominated by alien invasive plant species although pockets of indigenous vegetation did occur. Drawing from the principles of reticular biogeography an open space system was designed using the information gained from the vegetation survey and preliminary study. The design included: 4 core areas where conservation was a priority; 3 corridors linking the core areas and a number of buffer areas. A general management plan was subsequently developed for the system. Management suggestions were concerned with: ecological; economical and sociological aspects. The open space system offers Queensburgh the opportunity to contribute to the national reconstruction and development program (RDP) by upgrading the current standard of living of the local residents without compromising the natural resources available to future generations. / Thesis (M.Sc.)-University of Natal, 1994.
19

The effects of sediment disturbance on the macrobenthos of the St. Lucia Narrows, Natal.

Owen, Rodney Kenneth. January 1992 (has links)
Estuarine studies worldwide have shown that sediment disturbance effects on the macrobenthos are reIated to the nature and scale of the disturbance. Decreased species densities, diversity and richness have been found where the substratum and current patterns have been altered either by direct removal or by the creation of channels . Sediment disturbance in the St. Lucia Narrows has occurred through dredging, beam trawling and episodic floods. The Narrows, a meandering tidal channel approximately 21 km long linking the st Lucia Lakes to the sea, were dredged between 1952 and 1971 to provide a greater flow of seawater to the lakes during periods of low lake levels. A canal was cut through land from the Mfolosi River to the Narrows in an attempt to ameliorate hypersaline conditions in the Lakes, but was never commissioned. Beam trawling has formed the basis of a prawn bait fishery since the 1930's. The bait boats trawl on the mudflats over the entire Narrows on a daily basis and often churn the substratum with their propellers. The objectives of this study were to determine the effects of dredging, a once-off large scale disturbance, and beam trawling, a frequent small scale disturbance, on the macrobenthos of the Narrows. Studies in 1983 and 1984 showed that the dredged channel was impoverished compared with the adjacent mudflat, and that the Link Canal was devoid of benthos. In 1988 species densities, especially of polychaetes, were found to be lower in areas open to beam trawling than in adjacent closed areas. The dredged channel during the present study was again impoverished compared with the adjacent mudflats. The three most abundant species occurring on the mudflats, the crab Tylodiplax blephariskios, the amphipod Victoriopsia chilkensis and capitellid polychaetes, were recorded at densities an order of magnitude lower in the channel than on the mudflats. The substratum in the channel was generally sandier than the mudflats, and this condition appeared to be maintained by the scouring action of tidal currents. It was calculated that the creation of the dredged channel had reduced the standing benthic biomass in the Narrows by a minimum of approximately 20%. The Link Canal was colonised by the three major mud flat species , but at densities an order of magnitude lower than the mudflats. Beam trawling of experimental sites at monthly and 6-monthly intervals on muddy and sandy substrata in the Narrows between July 1989 and July 1990 did not appear to have a negative effect on the benthos. The coverage of the bait boats was calculated to be comparable to the trawling effort in this study, and suggested that the bait fishery is not having a detrimental effect on the benthos. It was concluded that the macrobenthos in the Narrows represented a pioneering community characteristic of estuaries, either not affected by, or able to recover from small scale and episodic disturbances provided that there was no long term habitat modification. / Thesis (M.Sc.)-University of Natal, Durban, 1992.

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