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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.
81

The effect of Acacia karroo tree density on grass species composition, forage yield and quality in different rainfall regimes in the Eastern Cape, South Africa

De Ridder, Cornelius Henry January 2016 (has links)
It is widely believed that Acacia karroo Hayne trees compete with and negatively affect the production of grasses in their immediate surroundings. This perception formed as a result of observations by farmers of their veld as well as some research. The complexity of plant interactions in different conditions required that research be done to better explain the extent of grass and tree interactions. In response to this need, the effect of a range of Acacia karroo densities on grass production was tested in areas of differing rainfall. Results emphasize the complexity of such plant interactions but highlight rainfall as influencing the effect of tree density on grass production and grass quality. Study sites were chosen with significant differences in tree density and rainfall and this was found to be concomitant with significant differences in grass yield and crude protein (p < 0.001). Grass yield (mass produced) was negatively correlated with tree density (p < 0.001) and was affected by rainfall. High tree density reduced grass yield at the lower rainfall sites, but a reduction in yield was only recorded during dry conditions in the higher rainfall areas. By contrast, the crude protein content of grasses was positively correlated to tree density (p < 0.001). However, as with yield, rainfall played an important part in the strength of the correlation. Soil properties such as temperature (-) (p = 0.011), phosphorus content (+) (p = 0.006), calcium concentration (+) (p = 0.005), acid saturation (-) (p = 0.018), and soil pH (+) (p = 0.008) were also significantly correlated to tree density. Tree density enriched the soil, subsequently benefitting grass quality. The study sites investigated, had different plant communities and environmental conditions with Cradock, Kubusi Drift and Kei Mouth having unique communities and conditions while Adelaide and Cathcart could not be separated in either. Cradock was the driest site and the vegetation was dominated by both grasses and karroid shrubs, differing in pattern and process from the other sites. The Kubusi Drift site had high tree densities, to the extent that the trees altered the grass species composition. The effects of rainfall on grass yield and quality exceeded that of community composition differences.
82

Habitat and foraging models as aids in the identification of priority areas for mitigating actions to reduce the incidence of electrocutions of the threatened Cape Griffon Gyps coprotheres in the Eastern Cape

Minnie, Johan Charles January 2009 (has links)
The Cape Griffon Gyps coprotheres is listed as a globally threatened species, because of threats posed by, inter alia, poisoning, loss of habitat, food shortages, electrocutions and drowning in high-walled farm reservoirs. The Cape Griffon has undergone major decline in South Africa, including the Eastern Cape. A detailed investigation into the causes of this decline is vital to ensure the survival of the species. Since it is known that electrocution on powerlines is a major cause of mortality of the griffons in the Eastern Cape, the study therefore focuses on this factor in this region. More specifically, the overall aim or objective of the study is to investigate, through the application of appropriate GIS techniques, the use of descriptive, empirical, habitat and foraging models to prioritise powerline networks, in the Eastern Cape, for mitigation to prevent electrocution of Cape Griffons Gyps coprotheres. The specific activities associated with the aim of the study are: (1) to identify the broad habitat types used by the griffons, (2) to determine the mean daily foraging range size of the griffons, (3) to map currently active foraging ranges and to categorise them according to their role, and the level of importance, in the foraging and breeding behaviour of the species, (4) to map the locations of networks of griffon-unfriendly powerline networks, and (5) to integrate the outcomes of (1) to (4) above, to produce a spatially explicit product that ranks griffon-unfriendly powerline networks according to their priority level for mitigation. The study uses simple descriptive models to investigate, spatially, the threat posed by griffon-unfriendly powerlines to the Cape Griffon in the Eastern Cape. The modelling approach includes a broad level simple habitat model (Categorical model), a Maxent model, a spatial foraging model and an electrocution model. Several map outputs were produced from the analyses. Cape Griffon habitat was successfully modelled using ecological input variables: biome, vegetation xvii type (suitable/unsuitable for griffon foraging), stock (cattle, sheep and goats), and stock farming types (commercial & communal). All outputs were modelled through the use of a Geographical Information System (GIS). Opportunistic sightings data were used for the study, which means that the data were collected on a non-systematic basis and are therefore considered incomplete. In ecology and zoogeography, incomplete datasets are common. To address this issue, a maximum entropy (Maxent) model was applied to the available dataset. Maxent produces predictions or conclusions from incomplete information, and was therefore useful for this study. The mean daily foraging area (coverage) of the Cape Griffon in the study area was estimated from published and unpublished marked bird studies conducted elsewhere, but in generally similar habitats. Based on all the data from these studies, it was considered appropriate to use a circular area, with a radius of 40 km, to represent the mean daily foraging range of the Cape Griffon in the Eastern Cape. It was considered appropriate to use a roughly circular area to depict the daily foraging area, given that the Cape Griffon qualifies as a central place forager. This means that the griffons are tied to a permanent site (roosting site or breeding site) and forage within a certain area around that central site. The mean daily foraging area (40 km) was applied to the currently active griffon sites: breeding sites, regular roosting sites, seasonal/occasional sites, and roosting sites (uncertain status). This produced four foraging area types, which formed the basis for the creation of two spatial foraging area models: Hierarchical Foraging Area Model (HFAM) and the Intersecting Foraging Area Model (IFAM). The HFAM produced three outputs: Primary, Secondary and Tertiary Foraging Areas. These three areas represent the hierarchical presentation of the relative importance of the four foraging area types. The outcome was areas of different predicted griffon occurrence: ‘high’, ‘medium’, ‘low’. The IFAM is essentially an extension of the HFAM, which represents a single area where foraging ranges based on all four types are intersected. The outcome represents the area of predicted highest griffon occurrence. The identified areas of different predicted griffon occurrence, or density (outputs of the HFAM and IFAM), were individually intersected with the layer that indicates the locations of the ‘unsafe’ powerlines. These intersects are depicted in hierarchical mode and expressed according to a number of four risk categories (very high, high, medium and low). The final spatial output of the study is a map that identifies priority powerlines for mitigation against griffon mortality caused by electrocutions and collisions with powerline infrastructure.
83

The importance of estuarine head waters for fishes in selected Eastern Cape systems, with particular emphasis on the influence of freshwater inflow, migration barriers and non-native predators on the juvenile and small fish component

Wasserman, Ryan January 2010 (has links)
The utilisation of estuary headwater environments by young estuary- and marine-spawned fish species was investigated together with the effects of riverflow alteration, in-stream barrier effects and non-native ichthyofauna on the nursery function of these habitats. The distribution and abundance of young estuary- and marine-spawned fish were sampled using seine and fyke nets in the headwater environments of four permanently open Eastern Cape systems, namely the Great Fish, Kowie, Kariega and Sundays Estuaries. Within the suite of study systems, the first of two case studies focussed on barrier effects of in-stream structures on fish migration. This was undertaken in the Sundays River. In the second case study, predation and competition dynamics of the non-native piscivorous Micropterus salmoides on estuary-dependent fish was investigated in the estuary headwater regions of the Kowie River system. In all four estuaries, young estuary-spawned fish species dominated the ichthyofaunal community followed by marine-spawned species, despite varied freshwater inflow resulting in headwaters varying in salinity from fresh to hypersaline. Fish community structure however, differed largely between estuaries, with both freshwater abstraction and unnatural elevation of freshwater into estuaries, as a result of inter-basin transfers, affecting these communities. In-stream structures were found to effect upstream movement of fish in two ways, dependent on the type of barrier. Partial (size-dependent) and complete (species-dependent) restriction to upstream migration of fish by causeway-type instream structures were observed. Weir-type in-stream structures acted as a complete barrier to most species, regardless of fish size. Predation of estuary- and marine-spawned fish species by large sized M. salmoides was recorded, although these fish did not contribute significantly to their diet during this study. However, the main dietary components found in smaller sized M. salmoides stomachs overlap with those of juvenile estuary- and marinespawned fish species, suggesting feeding competition between the juveniles of indigenous and non-native fish species.
84

Warthog as an introduced species in the Eastern Cape

Nyafu, Kanyisa January 2009 (has links)
The introduced common warthog, Phacochoerus africanus, in the Eastern Cape is increasing rapidly both in numbers and distribution, despite attempts by landowners to reduce numbers and exclude warthogs. These control attempts are motivated by concerns over the impacts of warthogs, on vegetation, soil and other animal species. This expansion of warthog populations is paradoxical given that a species of warthog occurred historically in this part of the world, apparently at low densities and was wiped out in the mid-1800s. The question therefore arises as to why warthogs are able to overcome population regulation attempts now, and this becomes an invasive species issue as the species now occurring in the Eastern Cape is in fact an introduced species. The objectives of the study were to investigate the status of warthogs as an introduced invasive species in the Eastern Cape by documenting the rate and direction of population expansion, ecological impacts and possible dietary shift of the introduced species, P. africanus compared to the extinct species P. aethiopicus. The research approach adapted here was to test the hypotheses that, (1) the success of P. africanus in the Eastern Cape reflects dietary differences of the two species based on observations of different dental adaptations, as P. africanus has functional incisors, which are absent in P. aethiopicus. Stable carbon isotope analysis of the tooth enamel was used to determine the diet of the two species. (2) Common warthogs are specialized grazers and will impact on a limited range of grass species, this hypothesis was addressed by describing the diet of common warthogs in one site in the Eastern Cape to identify plant species at risk due to invasion by P. africanus, and microhistological faecal analysis was used. (3) Common warthogs have successfully expanded their range in the Eastern Cape since their introduction and are now showing impact, this was addressed by describing the range of expansion of P. africanus in the Eastern Cape, as well as reviewing landowner perceptions of the impacts of warthogs, this was based on questionnaire surveys distributed in the Sundays and the Fish River valleys. The results of the study showed that there are differences in the diet of Cape warthog P. aethiopicus and common warthog P. africanus. The Cape warthog was largely a grazer (86 percent C4 grasses in their diet), while P. africanus is also a grazer (71 percent of C4 grasses in their diet), but with a larger proportion of browse in their diet. These results support the hypothesis that the presence of functional incisors in the common warthog might provide the common warthog with foraging advantages over the Cape warthog. This might be a contributing factor to the success of this invasive species in the Eastern Cape, and might explain the rapid disappearance of Cape warthogs in the 1800s, which coincided with rapid expansion of herds of domestic grazers. A total of twelve grass species are used by common warthogs and are therefore most vulnerable to impacts of this invasive species. Common warthogs are rapidly expanding their range particularly around the Sundays and the Great Fish River valleys and they are perceived by landowners to have impacts on grass cover, soils and fencing. This spread of warthog in the Eastern Cape exhibits characteristics of an invasive species. In light of the findings of this study, it is therefore important that government authorities and other parties concerned recognize that common warthogs are invasive in the Eastern Cape.
85

Frontiers of exclusion and enclusion: post-apartheid suburban social dynamics in East London, Beacon Bay

Buku, Luzuko January 2014 (has links)
This dissertation deals with the nature of the black middle-class assimilation in the South African suburban space, a space that was the sole preserve of the white middle-class during apartheid. It explores the relationship between these races as they come to meet in this space and what new identities are being formed. It also explores the relationship between both the black and white suburbanites and the urban poor who stay in an adjacent area to the suburb. The study uses the Beacon Bay area, which is constituted by one of East London’s most affluent suburbs and a poor township, Nompumelelo, to show how the emergent black middle-class has managed to enter this space in the post-apartheid era. Previous studies by Richard Ballard (2004) and Grant Saff (2001) have shown how the white middle-class has always been against any form of race or class mixing. Within the suburb, the new black suburbanites in Beacon Bay appear to have been welcomed but with conditions by their fellow white counterparts. The relationship between these two races does not stretch beyond meet and greets and it is only in the second generation black middle-class that you find better and non-superficial relations with fellow white suburbanites. In the older generation, the generation that experienced apartheid, the relationship between these two races has been that of tolerance and serious escape of contact unless when necessary. The children of both white and black families, though, have a far better relationship in school and in sport than their parents. This has created another area of contact for both these races and it bears potential for meaningful integration in the suburban space. Externally as it relates to relations between the black middle-class and the urban poor, the findings show that these new black suburbanites express a similar discomfort as the white suburbanites about the urban poor’s presence in the area. This shows that the evolution of the Beacon Bay suburb, with its deep-rooted discourse of white middle-class exclusivity, has not been entirely about hatred of the urban poor necessarily but about an identity ascription of what it means to live in a suburb. Despite these realities traditional ceremonies organised by the black middle-class in the suburbs and the church appear to be playing a role in creating relations between these suburbanites and the Nompumelelo residents. This is why we have decided to use the conceptualisation of the 18th century frontier zone as the borders of segregation within the suburb and between the suburban residents and those of the township can be crossed and re-crossed.
86

Rural internet connectivity: a development in Dwesa-Cwebe, Eastern Cape, South Africa

Mandioma, Martin January 2007 (has links)
This thesis presents aspects of Internet connectivity in rural South Africa. The work looks at government initiatives being undertaken to connect rural communities to up-to-date information networks. Various projects that seek to connect rural areas of South Africa, as well as other remote areas around the world, are discussed. These projects present many novel ideas that have been successfully used to link rural communities in remote areas with the information age. In particular, wired and wireless access technologies that can be implemented to connect remote communities to the Internet are discussed. A field test utilizing GPRS, VSAT and WiMAX was implemented in Dwesa-Cwebe, Eastern Cape Province, South Africa. VSAT proved to offer better Internet connectivity in terms of throughput and latency. WiMAX was then successfully implemented to relay the signal over the remote area of Dwesa-Cwebe, thus effectively providing Internet connectivity to an area with limited cell phone coverage and no telephone lines.
87

Exploring learning and teaching support given by principals to Grade R teachers in Mqanduli Area in the Eastern Cape

Pantshwa, Zimasa Prudence January 2013 (has links)
The study was conducted in the Mthatha District, Mqanduli area, and it sought to enquire about the role of junior secondary school principals in supporting Grade R teachers in order to make teaching and learning in the Grade R classes effective. The researcher has noticed with concern the poor conditions of Grade R classes in the schools and felt a need for proper support. She felt the principal could champion the concept of support better, in his capacity as a manager in the school. Studies in Early Childhood Development have been done, and they pertained to all aspects of child development, parental support etc., but studies that view support from a managerial perspective in Mthatha District are scarce. Under quantitative research design, a survey research method was employed to collect a large portion of the data. A questionnaire consisting of closed and open ended questions was used in order to collect data from the Grade R teachers. Open ended questions were used in order to get a broader view and perceptions. Comprehensive sampling was used in this study because the whole population fell into the sample. All ethical considerations were observes and after receipt of permission to conduct research in the schools, a questionnaire was distributed personally to all the schools in the sample. Data was analyzed by means of the SPSS. Some of the findings identified in the study pertained to: the need for material support including good infrastructure, poor communication between principal and Grade R teacher, scarce meetings specifically for Grade R. The individual findings, together with the implications were discussed in relation to the research questions. The researcher recommended that technical support should be attended to and the principal must communicate frequently with the Grade R teacher. Financial limitations and negative attitudes from some principals were the major limitations the researcher encountered.
88

Cape Town residential patterns : an examination of natural processes in housing and of the distortion of these natural patterns, all with special reference to Cape Town

Ehlers, Frederick Greeff 06 April 2020 (has links)
The study which follows is concerned with the housing of people within cities, and special reference is made to Metropolitan Cape Town in this context.The object of the study was to isolate certain principles relating to housing, formulating these in such a way that they might , in being tested , yield results useful to City Planners. (*1) Having established such principles, a further purpose of the study was to contrast these against other factors influencing housing such as Town Planning and Legislative Controls, and the effect the latter had upon the former. The principles which were the initial concern of the study originated in the Life Sciences (*2) and the Human Sciences (*3). Although the author cannot claim authority in any of these Sciences, the principles borrowed from them are well known , and served the valuable purpose of permitting a field theory to be constructed. Hypotheses , developed from this field theory, were tested and in so doing yielded some surprising and gratifying results. These results may be found on the pages following , and it will be seen that they appear to justify the method of approach .
89

Wupperthal: listening to the past

Bilbe, Mark January 1999 (has links)
Bibliography: pages 205-207. / The community of the Wupperthal Mission Station and its satellite stations, forms the focus of this text. The mission is situated in the Tra-Tra River Valley in the Cederberg Mountains of the Western Cape. In this text, I have sketched a series of vignettes to portray the lives of certain individuals, characters in the community's past and certain events throughout the history of the mission. The work is largely an oral history project, combined with a certain degree of philosophy of history as well as incorporating secondary sources where applicable. Though post-modem in certain aspects, this work incorporates sound modernist thought and academic practice. It is intended to be accessible to a wide readership, and prove to be entertaining as well as insightful. The scholarly endeavour driving this text is as sincere, as the history is real. It is a journey I encourage the reader to take with an open mind, taking time to savour the richness of the peoples' experiences. It is their quest for legitimacy, a combined search for truth, and my personal adventure.
90

Proposals for the development of the Cape of Good Hope Nature Reserve : annexure to thesis

Binckes, Graeme 06 April 2020 (has links)
The Cape of Good Hope Nature Reserve occupies the southern end of the Cape Peninsula and thus of the Southern Peninsula Subregion referred to in the general study (photographs 2 and 29). The Reserve has an area of nearly 29 1/2 square miles; its coastline is some 24 miles in length. It is used both as a Nature Reserve and as a recreation area, the latter function being concentrated, in the main, within restricted coastal sites; apart from these, Cape Point is a considerable tourist attraction as is the drive through the Reserve. Existing access routes and travelling times to the Reserve are shown on Map No. 5.1, together with current proposals.

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