Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
Trophic and habitat niche separation of fish community assemblages in the the Upper Shangani River and middle Zambezi River, Zimbabwe
Dissertation (MSc (Zoology))--University of Pretoria, 2018.
Saved in:
| Other Authors: | |
|---|---|
| Format: | Thesis |
| Language: | English |
| Published: |
2026
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867613508267409408 |
|---|---|
| access_status_str | Open Access |
| author2 | Woodborne, Stephan |
| author_browse | Woodborne, Stephan |
| author_facet | Woodborne, Stephan |
| collection | Thesis |
| description | Dissertation (MSc (Zoology))--University of Pretoria, 2018. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/110161 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:37:15.598Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/110161 Trophic and habitat niche separation of fish community assemblages in the the Upper Shangani River and middle Zambezi River, Zimbabwe Woodborne, Stephan u11140004@tuks.co.za Chimimba, Christian Timothy Adlam, Amanda Laura ephemeral perennial invasive stable isotopes habitat refugia freshwater fish Dissertation (MSc (Zoology))--University of Pretoria, 2018. Freshwater systems are severely threatened by anthropogenic disturbances including mining, pollution, deforestation, building of dams and introduction of exotic species. The result is degradation of the stream morphology that causes alteration and loss of habitats. The introduction of invasive species can lead to loss of native species through out-competition for resources and habitat. The aim of this study was to determine if ephemeral freshwater systems are refugia for native species against invasive species. This was done in the Upper Shangani River, which is an ephemeral system and at the time of sampling it was unknown whether it was invaded. The Middle Zambezi was used as a comparative site, as it is a mature perennial system and is known to be invaded by Nile tilapia (Oreochromis niloticus). The Shangani and Zambezi Rivers are also connected. Sampling took place in late wet season (June) and mid dry season (September) of 2017. Samples of fish, macroinvertebrates, vegetation and macrophtyes were taken for isotope studies of trophic structure. Habitat was characterised by variables within both river systems, and the habitat in which each fish was sampled was recorded. Fishes within the Shangani River selected habitat strongly based on stream morphology and bottom substrate, while the Zambezi River assemblage selected habitat based strongly on depth. In the Shangani River, there were fewer habitat types and therefore conspecifics overlapped their habitat use. The fish within the Zambezi River had an abundance of habitats and exhibited little overlap in habitat usage. Stable isotope analyses for carbon (_ 13C) and nitrogen (_ 15N) revealed a narrow trophic structure with only contribution of in- situ food resources in the Shangani River. The Zambezi River had a very wide trophic structure with inport of nutrients from upriver as well as riparian resources, and had many more generalist species. The low habitat heterogeneity and fewer resources within the Shangani River means that it is mostly occupied by specialist species and make it difficult for alien species to invade the system. The high habitat heterogeneity, wide trophic structure and abundance of food resources provide ample opportunity of invasions within the Zambezi River, as seen by the presence of O. niloticus. No O. niloticus or largemouth bass (Micropterus salmoides) were found in the main Shangani River. The Shangani River may be a refuge for native species as against a number of anthropogenic effects, including invasive species, provided the current flow regime is not altered by future human activities. Zoology and Entomology MSc (Zoology) 2026-05-15T17:26:31Z 2026-05-15T17:26:31Z 18/06/13 2018 Dissertation http://hdl.handle.net/2263/110161 en application/pdf |
| spellingShingle | ephemeral perennial invasive stable isotopes habitat refugia freshwater fish Trophic and habitat niche separation of fish community assemblages in the the Upper Shangani River and middle Zambezi River, Zimbabwe |
| title | Trophic and habitat niche separation of fish community assemblages in the the Upper Shangani River and middle Zambezi River, Zimbabwe |
| title_full | Trophic and habitat niche separation of fish community assemblages in the the Upper Shangani River and middle Zambezi River, Zimbabwe |
| title_fullStr | Trophic and habitat niche separation of fish community assemblages in the the Upper Shangani River and middle Zambezi River, Zimbabwe |
| title_full_unstemmed | Trophic and habitat niche separation of fish community assemblages in the the Upper Shangani River and middle Zambezi River, Zimbabwe |
| title_short | Trophic and habitat niche separation of fish community assemblages in the the Upper Shangani River and middle Zambezi River, Zimbabwe |
| title_sort | trophic and habitat niche separation of fish community assemblages in the the upper shangani river and middle zambezi river zimbabwe |
| topic | ephemeral perennial invasive stable isotopes habitat refugia freshwater fish |
| url | http://hdl.handle.net/2263/110161 |