- Title
- Evaluation of the mesozooplankton functional diversity indices in Algoa Bay as proxies to assess the stability of the food chain leading to the African penguin (Spheniscus demersus)
- Creator
- Rukuni, Praxedes Vimbai
- Subject
- Marine zooplankton --South Africa -- Algoa bay
- Subject
- Penguins -- South Africa -- Conservation
- Subject
- Fishes -- Predators of -- South Africa -- Algoa Bay
- Date Issued
- 2022-12
- Date
- 2022-12
- Type
- Master's theses
- Type
- text
- Identifier
- http://hdl.handle.net/10948/59956
- Identifier
- vital:62698
- Description
- Current unprecedented environmental changes threaten food web and ecosystem stability, which is particularly concerning in areas with vulnerable species such as the endangered African penguin Spheniscus demersus. In this study I adopted a holistic approach integrating many ecosystem levels to better understand African penguin behavioural ecology and food web stability. I investigated interplay between physico-chemical parameters and zooplankton functional diversity at various temporal and spatial scales in Algoa Bay. The study further investigated the applicability of zooplankton functional diversity (FD) in inferring African penguin food web stability by comparing the FD of zooplankton found in anchovies regurgitated from African penguins and the ones found in the Bay PELTER Stations. Gut contents of anchovies regurgitated from Bird Island and St Croix penguins were also evaluated using Frequency of Occurrence and Dominance methods and compared between colonies. Zooplankton FD in Algoa Bay varied over time but not at spatial scales with chlorophyll-a, Sea Surface Temperature (SST), turbidity and salinity being potential drivers of zooplankton FD. Chlorophyll-a and salinity were positively correlated with FD, meanwhile FD was inversely correlated to turbidity and SST. The study also observed minor differences in the physico-chemical parameters associated with African penguin foraging grounds, though different dietary preferences were found between the anchovies regurgitated from penguins from the two colonies. Anchovies regurgitated by penguins from Bird Island targeted large sized groups such as Decapods, meanwhile anchovies from the St Croix penguin colony targeted small sized Ostracods and Cirripedia. This study therefore, provides insight on the influence of fluctuations in physico-chemical parameters in shaping zooplankton communities in Algoa Bay. The study also emphasises anchovy dietary plasticity, switching from selective feeding to opportunistic feeding in instances of prey shortages which contributes to a stable African penguin food web in the face of climate change.
- Description
- Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2022
- Format
- computer
- Format
- online resource
- Format
- application/pdf
- Format
- 1 online resource (76 pages)
- Format
- Publisher
- Nelson Mandela University
- Publisher
- Faculty of Science
- Language
- English
- Rights
- Nelson Mandela University
- Rights
- All Rights Reserved
- Rights
- Open Access
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | SOURCE1 | Rukuni, PV Dec 2022.pdf | 1 MB | Adobe Acrobat PDF | View Details Download |