A dissertation submitted to the Faculty of Science,
University of the Witwatersrand,
in fulfilment of the requirements for the degree of
Master of Science,
Johannesburg, South Africa
2017 / Concerns exist over the continual decline of marula trees (Sclerocarya birrea subsp. caffra) as a result of African elephant (Loxodonta africana) impact and a lack of recruitment and regeneration. One strategy of protecting adult marula trees is the usage of elephant mitigation methods. This study took place in Jejane Private Nature Reserve (JPNR), a protected area which recently opened up to the Greater Kruger National Park and had not had elephants in over 100 years. The aim of the study was to investigate the changes to the marula population structure in JPNR three years after the migration of elephants to the area due to fence removal, and to test whether African honeybees (Apis mellifera subsp. scutellata) could be used as a mitigation method for elephant impact on marula trees.
A previous size-class survey had been done on a sample of JPNR’s marula population in 2009, prior to the fence removal in 2013. A resurvey of these trees was used to assess the elephant-induced impact and mortality levels on the marula trees and to compare these levels to previously recorded impact and mortality levels on marula trees in the Kruger National Park (KNP). Marula seed predation levels and seedling recruitment were also assessed to address recruitment concerns. The resurveyed marula population had declined by 23.8% post-elephant migration, with the highest annual mortality rates (AMR) and impact scores recorded for trees in the 5 - 11 m height classes. Impact scores on marula trees in JPNR were higher than impact scores recorded on KNP marula trees. Only two marula seedlings were found across all transects, with evidence of high seed predation on marula endocarps. JPNR displayed an adult-dominated marula population with a lack of regeneration, possibly due to a lack of fire which has increased available shelter for seed predators such as small mammals.
African honeybees were then used to investigate their effectiveness as an elephant mitigation method and to compare this method against wire-netting (a method experimentally used to prevent ring-barking by elephants). Fifty active beehives were hung from 50 marula trees, with another 50 dummy (inactive) beehives hung from branches on the opposite ends of each beehive tree’s main stem. Fifty additional marula trees were wire-netted and a further 50 were used as control trees. Elephant impact on all 150 trees was measured prior to the addition of treatments and post-treatment addition for nine months. 54% of the control trees received some form of elephant impact, in comparison to 28% of the wire-netted trees and only 2% of the beehive trees. Wire-netting protected marula trees against bark-stripping, but did not prevent elephants from breaking branches. Beehives proved highly efficient at mitigating all forms of elephant impact. The financial cost and maintenance required for the beehive mitigation method is greater than that of wire-
netting, but the beehives can provide honey and pollination services as an additional benefit. The results of this study illustrate that African honeybees can be used as an effective non-lethal mitigation method for elephant impact on marula trees and are a viable strategy to reduce human-elephant conflict in South Africa’s protected areas. / MT 2017
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/23490 |
| Date | January 2017 |
| Creators | Cook, Robin Michael |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | Online resource (ix, 90 pages), application/pdf |
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