Potential effects of different salinities on the survival of the mangrove crab, Uca urvillei and its associated chemoautotrophic bacterial symbionts
- Mbobo, Tumeka https://orcid.org/0000-0002-0159-6569
- Authors: Mbobo, Tumeka https://orcid.org/0000-0002-0159-6569
- Date: 2015-06
- Subjects: Mangrove ecology http://id.loc.gov/authorities/subjects/sh85080528 , Crabs--South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/19225 , vital:43033
- Description: The ability of natural populations to maintain fitness is important to their long-term persistence and has further relevance in the light of climate change scenarios. Fitness is however also influenced strongly by interactions with other species of the community. It is, therefore, important to focus on how environmental change can alter key biological interactions. The present study aimed to investigate the effects of different salinity levels on one species of mangrove crab, Uca urvillei and the associated chemoautotrophic bacterial symbionts, from the Mngazana estuary, South Africa. To examine the influence of different salinities over time on the symbiotic bacterial community, salinity experiments were set up, choosing three salinity exposures (5, 20 and 35percent) and four time exposures (3, 7, 14 and 21 days). The results showed that microbial community associated with U. urvillei was generally stable throughout the three salinity treatments, while the survival of the host (crab), was influenced by high salinities, particularly after day 14. Overall, the results of this study suggest that over time, environmental salinity (35percent) has the potential to affect significantly the physiology of U. urvillei, but this might not necessarily be the case for the associated microbial communities. The modes at which the significant symbionts are transferred from mother to offspring were also investigated by analysing the bacterial profiles from eggs, ovigerous and non-ovigerous females, along with mud. The results were fairly complex, but with significant differences in the bacterial communities of eggs from mud and females. These differences were driven mostly by two dominant phyla: Actinobacteria and Proteobacteria. The presence of both these phyla throughout the categories (even though in different percentages) suggest that U. urvillei might employ a mixed mode strategy of acquiring and maintaining the bacterial symbionts. Overall, this study contributes to further understand the dynamic and complex effects of environmental Abstract ii change on symbiotic communities, with overall potential cascading repercussions to the persistence of mangrove systems. , Thesis (MSc) (Zoology) -- Faculty of Science and Agriculture, 2015
- Full Text:
- Date Issued: 2015-06
- Authors: Mbobo, Tumeka https://orcid.org/0000-0002-0159-6569
- Date: 2015-06
- Subjects: Mangrove ecology http://id.loc.gov/authorities/subjects/sh85080528 , Crabs--South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/19225 , vital:43033
- Description: The ability of natural populations to maintain fitness is important to their long-term persistence and has further relevance in the light of climate change scenarios. Fitness is however also influenced strongly by interactions with other species of the community. It is, therefore, important to focus on how environmental change can alter key biological interactions. The present study aimed to investigate the effects of different salinity levels on one species of mangrove crab, Uca urvillei and the associated chemoautotrophic bacterial symbionts, from the Mngazana estuary, South Africa. To examine the influence of different salinities over time on the symbiotic bacterial community, salinity experiments were set up, choosing three salinity exposures (5, 20 and 35percent) and four time exposures (3, 7, 14 and 21 days). The results showed that microbial community associated with U. urvillei was generally stable throughout the three salinity treatments, while the survival of the host (crab), was influenced by high salinities, particularly after day 14. Overall, the results of this study suggest that over time, environmental salinity (35percent) has the potential to affect significantly the physiology of U. urvillei, but this might not necessarily be the case for the associated microbial communities. The modes at which the significant symbionts are transferred from mother to offspring were also investigated by analysing the bacterial profiles from eggs, ovigerous and non-ovigerous females, along with mud. The results were fairly complex, but with significant differences in the bacterial communities of eggs from mud and females. These differences were driven mostly by two dominant phyla: Actinobacteria and Proteobacteria. The presence of both these phyla throughout the categories (even though in different percentages) suggest that U. urvillei might employ a mixed mode strategy of acquiring and maintaining the bacterial symbionts. Overall, this study contributes to further understand the dynamic and complex effects of environmental Abstract ii change on symbiotic communities, with overall potential cascading repercussions to the persistence of mangrove systems. , Thesis (MSc) (Zoology) -- Faculty of Science and Agriculture, 2015
- Full Text:
- Date Issued: 2015-06
Re-imagining rural agrarian transformation in the Eastern Cape
- Mwangolela, Tafadzwa Fungayi
- Authors: Mwangolela, Tafadzwa Fungayi
- Date: 2008-11
- Subjects: Agricultural development projects , Agricultural innovations , Rural development
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/26559 , vital:65642
- Description: The research report is submitted to the School of Public Management and Development, University of Fort Hare as part of Masters in Public Administration requirements. The Provincial Growth and Development Plan 2004 2014 has identified agriculture as a critical pillar strategy of poverty reduction and growth in the Eastern Cape Province. The main aim of the study was to assess the viability of the agrarian transformation initiatives in the Eastern Cape. The study therefore was measuring the progress made by the agrarian transformation initiatives in selected areas versus the following variables food security, household community growth, participation and community involvement, and production support. In the attempt to achieve the main objectives, the study focused on the political economy of the rural as the policy context. The literature was an in-depth engagement with body of knowledge on agrarian transformations, with particular interest in governance participation and the impacts of agrarian initiatives in some countries. The product of literature analysis is the hypothetical model, termed the democratised rural agrarian transformation that should shape the policy implementation of agrarian reform. The study also undertook a field work that was guided by research methodology protocols from social science. The study thus collected primary data from 54 farmers participants drawn from 4 local municipalities within Chris Hani and Amathole District Municipalities. The findings of the study showed that there is still a challenge on the potential of rural agriculture to stimulate the improvement of food security status, and rural incomes. This reality is due to various factors such as poor farmer participation, weakness in coordination of the projects, limited access to extension services as a matter of capacity building. The study makes recommendations which are outlined a building local linkages integration with Local Economic Development initiatives and improvement of agrarian social infrastructure dynamic extension services, and political interventions. Conclusively there is need for an intergovernmental approach to the redress of the agrarian question in rural Eastern Cape. , Thesis (MPA) -- Faculty of Management and Commerce, 2008
- Full Text:
- Date Issued: 2008-11
- Authors: Mwangolela, Tafadzwa Fungayi
- Date: 2008-11
- Subjects: Agricultural development projects , Agricultural innovations , Rural development
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/26559 , vital:65642
- Description: The research report is submitted to the School of Public Management and Development, University of Fort Hare as part of Masters in Public Administration requirements. The Provincial Growth and Development Plan 2004 2014 has identified agriculture as a critical pillar strategy of poverty reduction and growth in the Eastern Cape Province. The main aim of the study was to assess the viability of the agrarian transformation initiatives in the Eastern Cape. The study therefore was measuring the progress made by the agrarian transformation initiatives in selected areas versus the following variables food security, household community growth, participation and community involvement, and production support. In the attempt to achieve the main objectives, the study focused on the political economy of the rural as the policy context. The literature was an in-depth engagement with body of knowledge on agrarian transformations, with particular interest in governance participation and the impacts of agrarian initiatives in some countries. The product of literature analysis is the hypothetical model, termed the democratised rural agrarian transformation that should shape the policy implementation of agrarian reform. The study also undertook a field work that was guided by research methodology protocols from social science. The study thus collected primary data from 54 farmers participants drawn from 4 local municipalities within Chris Hani and Amathole District Municipalities. The findings of the study showed that there is still a challenge on the potential of rural agriculture to stimulate the improvement of food security status, and rural incomes. This reality is due to various factors such as poor farmer participation, weakness in coordination of the projects, limited access to extension services as a matter of capacity building. The study makes recommendations which are outlined a building local linkages integration with Local Economic Development initiatives and improvement of agrarian social infrastructure dynamic extension services, and political interventions. Conclusively there is need for an intergovernmental approach to the redress of the agrarian question in rural Eastern Cape. , Thesis (MPA) -- Faculty of Management and Commerce, 2008
- Full Text:
- Date Issued: 2008-11
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