Masters Degrees (Conservation Ecology and Entomology)

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Browsing Masters Degrees (Conservation Ecology and Entomology) by Subject "African elephants (Loxodonta africana) -- Feeding and feeds"

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    Spatial and feeding ecology of elephant (Loxodonta africana) on Sanbona Wildlife Reserve, Little Karoo, South Africa.
    (Stellenbosch : Stellenbosch University, 2019-04) Swanepoel, Pascale; Leslie, Alison J.; Vorster, Liesl; Vorster, Paul; Stellenbosch University. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology.
    ENGLISH ABSTRACT: African elephants (Loxodonta africana) are megaherbivore mixed feeders. They are an important keystone species, influencing a variety of factors within an ecosystem. Historically elephants migrated throughout large parts of South Africa, including the valleys of the Little Karoo. However, these seasonal migration routes have long since disappeared and most of these large herbivores now only occur in South Africa within fenced reserves. This containment of populations can have a negative impact on landscapes as areas are utilised across seasons, thus not allowing vegetation a recovery period. In a sensitive semi-arid environment such as the Little Karoo, this has been a concern with the reintroduction of such large herbivores, as their spatial use and feeding ecology are largely unknown in this area. Sanbona Wildlife Reserve is a 57 600-ha reserve in the Little Karoo which has reintroduced various animals since its creation in 2002. Since the introduction of elephants in 2003 and 2009 the population has increased to 17 individuals between two herds. Habitat heterogeneity, local rainfall, and spatio-temporal distribution of food and water are some of the key elements determining the size and structure of elephants’ home ranges. GPS satellite collars were used to determine the areas utilised by both elephant herds on the reserve. An individual from each elephant herd was fitted with a GPS satellite collar which recorded their hourly movements over an 18-month period. The data collected were utilised to determine home ranges and core zones using the Kernel Density Estimate and Grid Square Methods. Weather patterns were also recorded throughout the study period through the use of weather stations and observations. This information was used to determine the influence of weather on seasonal spatial usage as well as the impact of water points on their movement on the reserve. Results indicated the importance of river lines within both elephant herds’ core zones, however mountain slopes and open valleys were also utilised within their home ranges. The Northern herd’s home range spanned over 25% of the available area (60.4 km2) whereas the Southern herd had a home range of 73.9 km2, 31% of the available area. Furthermore, results show that rainfall, temperature, seasonal vegetation growth and water availability influence seasonal spatial usage.The preferred space utilised correlates with the elephants’ diet preferences. Previous studies of elephant diet in semi-arid to arid environments recorded the utilisation of a combination of graze (C4), woody browse (C3) and succulent browse (CAM), with season and habitat determining the percentage present in the diet. A combination of scan sampling and isotopic analysis of faeces samples was used to better understand the diet of elephants on Sanbona Wildlife Reserve. Results from the scan sampling show that a variety of plant species (at least 94) were recorded to constitute the elephants’ diet. Through the combination of both methods over a 16-month period seasonal differences in diet and between herds was recorded. The Northern herd's diet consisted of 62% browse species, 28% graze and 10% succulents, compared to 79% browse, 2% graze and 19% succulent species in the Southern herd's diet. The results of this study will help Sanbona Wildlife Reserve to better understand the ecological requirements of elephants within this area, as well as their impact on sensitive, slow growing plant species on the reserve. This information will allow wildlife management to make informed decisions with regards to population management strategies.