Population dynamics of the Zuurberg Cycad and the predicted impact of climate change
- Authors: Singh, Karishma
- Date: 2012
- Subjects: Cycads -- South Africa -- Eastern Cape , Encephalartos -- South Africa -- Eastern Cape , Climate change -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10633 , http://hdl.handle.net/10948/d1012857
- Description: Cycads first appeared about 300 million years ago and historical data indicates that they survived fluctuations of global temperature and carbon dioxide concentrations and reached peak abundance during periods where temperature and carbon dioxide concentrations were much higher than the present conditions as well as the predicted increased levels. With Africa being one of the most vulnerable regions to climate change and in the absence of an evaluation of predicted impacts of climate change on cycads, this study aims to contribute to our understanding of responses of Encephalartos longifolius to increased temperature. Encephalartos longifolius (Jacq.) Lehm is an Eastern Cape endemic and like most cycads has been around for millions of years with very little change to its basic structure. Photosynthetic rates showed E.longifolius seedlings have C3 photosynthesis and even under stress they do not switch over to CAM photosynthesis. The photosynthetic rates of seedlings showed a typical C3 -plant type response under elevated carbon dioxide levels. Increased temperatures could be detrimental to the species but coupled with elevated carbon dioxide levels the growth of Encephalartos longifolius are postulated to outweigh the negative impacts of increased temperatures. Whilst climatic conditions in the Eastern Cape might not impact the abundance of Encephalartos longifolius, the species however is declining rapidly to the present near-threatened status. Demographic studies revealed a high percentage of juvenile numbers in the wild; however juvenile plants are impacted on by animals thereby jeopardizing their survival. Adult plants are heavily impacted on by animals; this reduces the probability of new offspring being produced. Cycads are also very slow - growing which is the primary cause of their ruin in the wild. Encephalartos longifolius grows at just over approximately 1 cm per year with growth being more rapid in the juvenile plants. Once juvenile plants reach approximately 60 cm they stop growing in diameter but only get taller. Seed germination is also a very slow process with an optimum temperature of 28°C and a growth medium of at least 50 percent moisture. Regardless of the Eastern Cape predicted to become the hottest province in South Africa as a result of climate change, cycads will be able to adapt to the changing environment and conservation plans should focus on animal and human impacts that are the major force causing decreasing abundance of Encephalartos longifolius in the wild.
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- Date Issued: 2012
Cyber crime affecting some businesses in South Africa
- Authors: Herselman, Martha Elizabeth
- Date: 2003
- Subjects: Computer crimes , Business enterprises -- South Africa
- Language: English
- Type: Thesis , Masters , MTech (Business Information Systems)
- Identifier: vital:10793 , http://hdl.handle.net/10948/212 , Computer crimes , Business enterprises -- South Africa
- Description: This study shows that cyber crime is a recent addition to the list of crimes that can adversely affect businesses directly of indirectly. This phenomenon was not directly prosecutable in South Africa until the enactment of the ECT Act in July 2002. However this Act also prevents businesses to fully prosecute a hacker due to incompleteness. Any kind of commercially related crime can be duplicated as cyber crime. Therefore very little research appears or has been documented about cyber crime in South African companies before 2003.11.21 The motivation to do this study was that businesses often loose millions in cyber attacks, not necessarily through direct theft but by the loss of service and damage to the image of the company. Most of the companies that were approached for interviews on cyber crime were reluctant to share the fact that they were hacked or that cyber crime occurred at their company as it violates their security policies and may expose their fragile security platforms. The purpose of this study was to attempt to get an overall view on how South African businesses are affected by cyber crime in the banking and short term insurance sector of the South African industry and also to determine what legislation exist in this country to protect them. The case study approach was used to determine the affect of cyber crime on businesses like banks and insurance companies. Each case was interviewed, monitored and was observed over a period of a year. This study discloses the evaluation of the results of how cyber crime affected the cases, which were part of this study. The banks felt that they were at an increased risk both externally and internally, which is likely to increase as the migration towards electronic commerce occurs. The insurance industry felt that they are not yet affected by external cyber crime attacks in this country.
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- Date Issued: 2003