The Masai Mara Game Reserve of southwestern Kenya forms the northernmost extension of the Serengeti ecosystem and provides the critical dry season range for approximately 1.5 million migratory wildebeest. Over the past 100 years, major ecological changes have occurred. The area has experienced a transformation from open grassland to dense woodlands and back. This study addressed the transition in the Mara woodlands from both an historical and a contemporary perspective. The study focused on two central questions: 1) what factor (or factors) were responsible for the decline of the woodlands in the 1960s? And 2) what factor (or factors) are currently responsible for inhibiting woodland regeneration? In the 1880s an introduced disease, rinderpest, decimated wild and domestic ungulates in the Serengeti-Mara region. Local pastoralists, dependent on their livestock for survival, succumbed to disease and starvation. Elephant numbers had also been greatly reduced by indigenous hunters. Explorers, slave traders, and hunters described the area as an open grassland by 1900. In the following decades, conditions were conducive to the establishment of woodlands; burning rates were low and elephant browsing was negligible. By the 1930s, the area was covered by dense woodland. These woodlands began a steady decline several decades later. Unusually high rainfall, high grass productivity, and severe fires characterized the period of greatest decline (1961 1967). Although woodland losses were initially viewed as "elephant problems", findings from this study suggest that fire was the primary factor in the disappearance of woodlands, while elephants merely accelerated the rate of decline. Elephants preferred open grasslands, swamps, and relict thickets in the wet season. However, in the dry season, elephants selected wooded habitats. Average group size was significantly higher in the wet season than the dry. Mara elephants fit the same feeding patterns reported for many African elephant populations. Elephants concentrated on grasses and herbs in the rainy season and browse in the dry season. In general, males browsed more than females, while females ate more diverse diets containing more herbaceous matter. Elephants utilized seedlings under 1m more than any other height class of trees throughout the year. This pattern of selective feeding significantly reduced seedling survivorship. Large-scale field experiments subjected plants to three treatments: browsed only, browsed and burned, and neither browsed nor burned. Although fire, at current fuel loadings and intensities, produced an almost total topkill, the majority of burned individuals resprouted within six months. Elephants removed a significant proportion of seedlings and severely damaged others. Wildebeest inhibited seedling growth through trampling, thrashing, and accidental browsing. Only those seedlings protected from both burning and browsing increased in height. Woodland dynamics in the Mara are currently more affected by elephants, wildebeest, and other browsers than by fire. Elephants can be considered a "keystone" species in this system. I concluded that elephants were not capable of initiating the woodland declines which started over two decades ago. However, once tree densities had been reduced by previous perturbations (such as increased burning rates following a reduction in wildebeest numbers and an increased frequency of man-made fires), elephants accelerated the rate of decline. My findings did not support Caughley's "stable limit cycle" hypothesis. Today, elephants are holding the Mara in a grassland phase, despite low burning rates. This pattern suggests that the Mara may have two locally stable states, woodland or grassland, and that an external factor such as fire is necessary to move the system between the two. Elephants, alone, apparently cannot move the system from one state to another, but once it is in the grassland phase, they can hold it there. / Science, Faculty of / Zoology, Department of / Graduate

A Dissertation Submitted to the Faculty of SCience University of the Witwatersrand. Johannesburg for the Degree of Master of Science / This study of the impact of elephants, Loxodonta africana (Blumenbach), in private reserves ln South Africa's lowveld region aimed to determine the sizes and species of woody plants most often affected by elephants and the proportion and severity of elephant impact on the marula tree Sclerocarya birrea. The study was conducted in three parts: vegetation quadrats in areas where elephants had been foraging, direct observation of the feeding behaviour of hand-raised elephants, and transects to sample S. birrea across the study areas. To distinguish preferences, the frequency of elephant impact on each species was compared with the frequency with which it was encountered by the elephants. In the vegetation quadrats, I found that uprooting and leaf stripping were infrequent in all sizes of stems, Main stem breakage affected stems lese than 30 cm in diameter whereas branch breakage and bark stripping increased with increasing size. Favoured species were Combretum collinum, Acacia gerrardii, Albizia harveyl sclerocarya birrea, Dalbergia metenoxyton, and Pterocarpus rotundifolius. Notable among neglected species were Acacia toriifis, Tettnmelle prunioides, and Terminalia sericea which are favoured food items for elephants elsewhere. Other common species which were not selected by elephants were Acacia exuvielis, Cassine transvaalensis, Ehretia emoene, Euclea netalensis and Securinega virosa. Behavioural observation revealed that hand-raised elephants favoured eating Sclerocarya birrea, Combretum epiculeium, and Acacla nigrescens. The elephants stripped bark from A. nigrescens and S. birrea. Assessment of rnarula trees revealed that elephant impact killed fewer than 2% of stems during the preceding season. Fewer than 24% of trees had current season breakage or bark removal. Main stem breakage Was found in stems smaller than 40 ern in diameter. Ring barking was concentrated on the larger size classes, while the smaller size classes escaped any detectable form of elephant impact. / Andrew Chakane 2018

This study looks at the impact of elephant feeding on the Xeric Succulent Thicket component of Eastern Cape Subtropical Thicket (ECST) in Addo Elephant National Park (AENP). Observations of elephant feeding were carried out and vegetation transects were surveyed for impact of elephant feeding. The results indicated that the Nyati elephants spent the majority of their time grazing (nearly 90%), particularly the cow-young herds, and especially when the herd gathered in larger numbers. Browsing events were concentrated on Acacia karroo (81%) and there was no significant difference between the sexes in their preference for this species. Despite being subjected to most of the browsing, the majority of A. karroo trees were undamaged and the effect of elephants was generally light. It appears unlikely that, three years after re-introduction to Nyati, the elephants have had an effect on community structure of the vegetation. Surveys were conducted on stands of the alien invasive weed prickly pear Opuntia ficus-indica, and it was recorded that elephants in Nyati have had a dramatic effect on prickly pear, utilising all adult plants assessed and destroying 70% of them. This level of destruction in such a short period of time suggests that prickly pear is a highly favoured species. The results from the present study suggest that elephants can play a role in the control of prickly pear. Results are discussed in terms of elephants as both megaherbivores and keystone species, and as agents of intermediate disturbance.

The development of small (<300 km²), private game reserves has become a trend, not only in the Eastern Cape Province, but also elsewhere in South Africa as a result of a shift in land use practise from agriculture to ecotourism. The resultant re-introduction of elephants to many of these reserves has lead to management concerns because of the limited research on small reserves regarding their impact on the vegetation. In this study I assessed the space use, habitat selection, diet and impact of two elephant populations on the vegetation in the Eastern Cape Province between February 2004 and March 2005. Home range sizes were calculated using the kernel utilization distribution method. Home range sizes for elephants on Kwandwe were significantly larger during summer than winter (p<0.05). There was no significant difference between the home range sizes of the herds and males within a season and during summer the elephants utilized about 75 % of the reserve and only 54 % during winter. On Shamwari, the herd utilized about 92 % of the reserve during summer and 83 % during winter; while the males utilized 76 % of the reserve. Core areas for both elephant populations shrank from summer to winter and were concentrated around the permanent water sources on each reserve. Habitat selection was assessed using χ² tests and Bonferroni confidence intervals. On Kwandwe, there was a significant difference between observed and expected use of vegetation types (p<0.05) and karroid shrubland was strongly avoided by both herds during summer and winter. The preferred vegetation types of the males ranged from relatively open (short euphorbia thicket, bushclump karroid thicket and karroid shrubland) to completely open (old lands). On Shamwari, subtropical thicket, bontveld and montane grassland were avoided; while primary and secondary acacia thicket, riverine thicket and cultivated lands were preferred. The predominant vegetation type in the home ranges of herds on Kwandwe and Shamwari was subtropical thicket. The diet was assessed by direct observations over two seasons and dietary preferences were calculated. There was a significant difference in the frequency of occurrence of plants in the diet on the two reserves (p<0.05) and no significant effect of time of day or season (p>0.05). Seventeen woody plant species were utilized on Kwandwe and 23 species were utilized on Shamwari. Grass constituted a significantly greater percentage of the diet in summer than winter (p<0.05). Elephants on Kwandwe showed a selective preference for Ozoroa mucronata, Pappea capensis and Acacia karroo; while on Shamwari, A. karroo was selected. Transects were conducted in two different vegetation types on each reserve so as to assess the impact of elephant on the vegetation and damage scores were then calculated from these data. There was no significant effect of vegetation type or elephant density on mean damage scores in Kwandwe (p>0.05). Five hundred and seventy-eight plants were assessed in the subtropical thicket vegetation type and 225 plants were assessed in the savanna-type vegetation, with more than half the trees showing low levels of damage that could not only be attributed to elephants. Mean damage was highest for Portulacaria afra and Pappea capensis in subtropical thicket and for Rhus spp. in the savanna-type vegetation. On Shamwari, 408 plants were assessed in subtropical thicket and 215 in the savanna-type vegetation, with more than 70 % of trees showing low levels of damage. There was a significant effect of plant species and elephant density on the mean damage scores in subtropical thicket, with Aloe ferox showing more damage than the other plant species (p<0.01). In the savanna-type vegetation, A. karroo was the most severely damaged. Overall, damage was greater in the thicket vegetation type compared to the more open vegetation type on both reserves.