- Title
- The ecology of Impala (Aepyceros melampus) in a dystrophic system: a case study from Welgevonden Game Reserve, Limpopo Province, South Africa
- Creator
- Pieterse, Marilize
- Subject
- Impala -- Habitat -- South Africa -- Limpopo province
- Subject
- Impala -- Feeding and feeds -- South Africa -- Limpopo province Ecology -- South Africa -- Limpopo province
- Date Issued
- 2019
- Date
- 2019
- Type
- Thesis
- Type
- Masters
- Type
- MSc
- Identifier
- http://hdl.handle.net/10948/43240
- Identifier
- vital:36768
- Description
- Impala (Aepyceros melampus) have been extensively researched and are known to flourish in Savanna ecosystems. They are a very adaptable species switching easily between grazing and browsing hence their classification as mixed feeders. However, little published research has been done on impala and their adaptability to sour nutrient-poor savannas. On Welgevonden Game Reserve (WGR), situated in the dystrophic Waterberg Mountain Range, impala have poor body condition and negative growth rates. Research shows that impala are on the threshold of being sexually dimorphic which can lead to a difference in the habitat selection and preference, diet composition and diet quality of adult male and female animals. This study served as a baseline study to understand the adaptability and ecology of impala in the Waterberg. The key research question was: How do male and female impala adapt to the area in terms of habitat selection and preference, and diet composition and quality, across the seasons of a year in the sour nutrient-poor Waterberg Mountain Range? This was the first study on impala in the area that looked at all the above-mentioned factors. A combination of observational studies, for habitat selection and preference, and faecal analysis, for diet composition and diet quality (faecal Nitrogen (Nf) and Phosphorous (Pf)), were used. It should be noted that WGR received below average rainfall and above average maximum temperatures over the past seven years. Impala on WGR are limited by the availability of suitable habitat and the quantity and quality of forage. They therefore suffer from nutrient deficiency. Spatial and ecological segregation between male and female animals occurred due to differences in sexual status and the constraints associated with this. Overall, very little variation in habitat use occurred between Wet and Dry seasons, emphasizing limited suitable impala habitat. Impala on WGR showed a distinct preference and avoidance of different habitat types. Both male and female preferred Short Grassland throughout the year. This is the smallest habitat type on the reserve and is dominated by Cynodon dactylon, which mostly occurs in the low-lying areas of the reserve. Both male and female impala avoided Hill Slope and Long Grassland throughout the year. These habitat types are characterized by steep slopes, medium to extensive rock cover, long sparse grass and dense tree cover. The Long Grassland habitat type consist mainly of old lands in different stages of regeneration dominated by dense unpalatable grasses. Both male and female impala were highly selective towards the most nutrient rich areas, which predominantly included the Short Grassland habitat type. The factors important to impala habitat selection are short to medium grass height (6-25 cm), ecotones in low lying areas between Short Grassland and woodland, proximity to water (0.96-1.5 km), moderate to no slopes, a burn interval of less than 3 years, the dominant occurrence of Cynodon dactylon, and the presence of Dichrostachys cinerea, Grewia flavescens, Dombeya rotundifolia and Indigofera melanodenia. The impala population on WGR appears to be limited by a lack of quality forage. The diet composition of impala on WGR followed a seasonal pattern, with a higher grass to browse content during the Wet seasons, and a higher browse to grass content during the Dry seasons. Furthermore, impala on WGR have a higher browse content in their diet than in other areas of South Africa. The higher content of browse in the impala’s diet on WGR is probably due to the impala optimizing their diet quality due to a lack of quality grasses, such as Cynodon dactylon, available to them on the reserve. Females consumed higher amounts of browse than males during lactation in order to optimize their diet quality. In general, impala experienced nutrient deficiencies during the Dry seasons as indicated by Nf and Pf values which were below the accepted threshold values for impala. This appears to have affected their body condition, reproductive success and survival. The below threshold values of Nf and Pf indicate that their numbers exceeded the ecological capacity of the reserve at the time of the study. This dystrophic savanna is marginal for impala. This indicates that even large reserves in the sour bushveld communities of the Waterberg Mountains are unlikely to sustain impala populations in a healthy productive state.
- Format
- XXX leaves
- Format
- Publisher
- Nelson Mandela University
- Publisher
- Faculty of Science
- Language
- English
- Rights
- Nelson Mandela University
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | SOURCE1 | M. Pieterse 212292072.pdf | 2 MB | Adobe Acrobat PDF | View Details Download |