Garden at 43 Admiralty Way, Summerstrand, Port Elizabeth
- Authors: Skead, C J (Cuthbert John)
- Date: 2000-04-23
- Subjects: Encephalartos -- South Africa -- Eastern Cape , Aloe africana -- South Africa -- Eastern Cape , Aloe ferox -- South Africa -- Eastern Cape , Plants -- South Africa -- Eastern Cape , Gardens -- South Africa -- Eastern Cape
- Type: still image
- Identifier: vital:13388 , http://hdl.handle.net/10962/d1016900
- Description: Cycad Encephalartos with Aloe africana and Aloe ferox in background.
- Full Text: false
- Date Issued: 2000-04-23
Garden at 43 Admiralty Way, Summerstrand, Port Elizabeth
- Authors: Skead, C J (Cuthbert John)
- Date: 2000-04-23
- Subjects: Encephalartos -- South Africa -- Eastern Cape , Plants -- South Africa -- Eastern Cape , Gardens -- South Africa -- Eastern Cape
- Type: still image
- Identifier: vital:13390 , http://hdl.handle.net/10962/d1016902
- Description: Encephalartos sp. with cones
- Full Text: false
- Date Issued: 2000-04-23
Garden at 43 Admiralty Way, Summerstrand, Port Elizabeth
- Authors: Skead, C J (Cuthbert John)
- Date: 2000-04-23
- Subjects: Encephalartos -- South Africa -- Eastern Cape , Aloe ferox -- South Africa -- Eastern Cape , Strelitzia reginae -- South Africa -- Eastern Cape , Plants -- South Africa -- Eastern Cape , Gardens -- South Africa -- Eastern Cape
- Type: still image
- Identifier: vital:13387 , http://hdl.handle.net/10962/d1016899
- Description: Encephalartos altensteinii plants (left hand one with at least three cones) at the base of one Encephalartos. With Aloe ferox and Strelitzia reginae in background.
- Full Text: false
- Date Issued: 2000-04-23
Garden at 43 Admiralty Way, Summerstrand, Port Elizabeth
- Authors: Skead, C J (Cuthbert John)
- Date: 2000-04-23
- Subjects: Encephalartos -- South Africa -- Eastern Cape , Aloe ferox -- South Africa -- Eastern Cape , Plants -- South Africa -- Eastern Cape , Gardens -- South Africa -- Eastern Cape
- Type: still image
- Identifier: vital:13389 , http://hdl.handle.net/10962/d1016901
- Description: Two species of cycad, one with cone, with Aloe ferox on hand.
- Full Text: false
- Date Issued: 2000-04-23
Garden at 43 Admiralty Way, Summerstrand, Port Elizabeth
- Authors: Skead, C J (Cuthbert John)
- Date: 2000-04-23
- Subjects: Encephalartos -- South Africa -- Eastern Cape , Plants -- South Africa -- Eastern Cape , Gardens -- South Africa -- Eastern Cape
- Type: still image
- Identifier: vital:13391 , http://hdl.handle.net/10962/d1016903
- Description: Encephalartos sp. with four cones, only three visible.
- Full Text: false
- Date Issued: 2000-04-23
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.
- Full Text:
- Date Issued: 2012