No description available.

Human-elephant conflict (HEC) occurs across Africa and is a major threat to the continued existence of the African elephant. To effectively implement mitigation measures, a thorough understanding of the spatial and temporal patterns of HEC is required. This study used a systematic, grid-based geographical information system (GIS) to analyse the spatial and temporal relations of HEC intensity in 2004 and 2008 with underlying environmental variables in a forest habitat, the Bia Conservation Area (BCA), Ghana. Relationships between crop-raiding incident data, Moderate Image Resolution Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI) values and remotely sensed derived data were investigated at a 10 km2 scale using principal components analysis (PCA) and correlation analysis. Crop-raiding was found to be clustered into distinct areas. The onset of crop-raiding in 2004 and 2008 can be attributed to seasonal variation in vegetation biomass. Decreases in EVI values were matched with crop-raiding incidents. The high number of crop-raiding incidents in 2004 could be attributed to the large fluctuations in vegetation biomass in comparison to 2008. HEC intensity was not significantly related to the environmental variables analysed at the 10 km2 scale. These results suggest that HEC intensity may be influenced by vegetation quality, soil mineral content and/or human density. A grid-based GIS system with a 10 km2 resolution used in combination with remotely sensed data and statistical tools is useful for identifying spatial patterns of HEC, even with relatively small incident data sets. The methods used in this study could be applied to other forest habitats experiencing HEC for comparative analysis. The influence of vegetation quality, soil mineral content and human density on HEC intensity in forest habitats requires further analysis.

Ph.D., Faculty of Science, University of the Witwatersrand, 2011 / 1 Investigating the life history strategy of an African savanna tree, Sclerocarya birrea subsp. caffra (marula) Chantal Vinisia Helm Abstract Lack of understanding of the life history attributes and responses of savanna woody plants to disturbances, as well as the observation of unstable population structures in a keystone, savanna tree, Sclerocarya birrea subsp. caffra (marula), prompted this study. This study employed a combination of empirical, experimental and model formulation techniques, aimed at achieving its ultimate purpose of understanding the life history strategy of marula in the face of disturbance. Four main population structures were identified for marula in the low altitude savannas of South Africa: 1) adult dominated, 2) juvenile dominated, 3) with a “missing size class” and 4) stable (negative J-shaped). Spatial variability in structure indicated different drivers affecting different populations. High annual mortality rates of up to 4.6% in adult trees, no recruitment out of the fire trap and little regeneration were observed in the Kruger National Park (KNP) between 2001 and 2010, and consequently even greater instability in the structure of these populations already observed earlier in the decade. Growth rates of saplings between 2 and 8 m in height and 2 and 30 cm in stem diameter in the field were monitored between 2007 and 2010. Annual growth rates of up to 11 mm in diameter and up to 22 cm in height were observed. Annual relative growth rates ranged between 1.9 and 4.8% across sites. Growth rates were positively linked with rainfall and plant size. Growth rates, biomass allocation patterns, as well as storage and defence allocation in 3 to 28 month old marula seedlings were assessed under glasshouse conditions. Relative growth rates were highest directly after germination (20%), but did not exceed 5% thereafter. Allocation to roots (already 65% of the overall biomass at 3 months of age and >80% when older) was high regardless of soil type or provenance. Provenance affected height gain, and plants germinating from seeds collected at higher rainfall sites had faster height growth rates than those from seeds collected at lower 2 rainfall sites. Allocation to storage in the form of root starch peaked at 35%, while allocation to defence in the form of phenolics in the leaves peaked at 18%, being relatively higher than other species. No trade-off between growth and defence allocation was observed. However, in the second growing season, growth at the start coincided with a 50% decrease in starch reserves in the roots. Reproductive maturity was found to occur after 46 years and escape from the fire trap after 12 years in a disturbance free environment. Marula trees appear to be able to live for up to 300 years of age. High temporal variability in fruit production was observed, marginally linked to rainfall. Only 2% of seeds persisted for more than one year, and hence marula relied mostly on the current season’s fruit crop for input of new germinants. Fruit production was highly synchronous across trees at a site. Very high levels of seed predation were observed. Marula seeds can remain dormant for at least 10 years when stored in the laboratory. Germination takes place after 3 mm of rainfall every four days for two weeks and is enhanced by acid digestion and high temperatures. Germination percentages are relatively low (<50% of the endocarps). Marula seedlings appear highly adapted to fire, with high allocation to below-ground biomass and starch storage, as well as very thick bark from very small stem diameters, including a well developed resprouting response from very young. Marula stems were able to resist fire from 3.4 cm in stem diameter, and were completely resistant above 7 cm. Stem diameter growth was prioritised above stem height growth, indicating that in marula, diameter gain is more important than height gain in escaping the fire trap. Topkilled marula saplings are able to regain their prefire height within one season. However, rainfall patterns may have an overriding effect on these growth patterns. Adult trees appear to be made vulnerable to fire through bark stripping, toppling and pollarding and the subsequent invasion of the soft wood by borers. On nutrient-poor granite soils, marula has a resistant strategy to herbivory, however on nutrient-rich basalt soils, marula overcompensates for herbivory even at very low levels. This may explain why marulas are more vulnerable on basalt soils in the KNP, having 3 already been extirpated from the northern arid basaltic plains. Marula seedlings are extremely drought resistant through fast root penetration rates and high root: shoot ratios. A simple demographic model was developed which predicted that marula populations are unlikely to survive given the current elephant impact in the KNP and if the fire interval is less than once every seven years. Even though marula is highly resilient to damage from herbivory or fire alone, the combination of frequent fire and heavy utilisation is proving fatal for marula populations in the KNP and elsewhere. In terms of other savanna tree species, marula is an outlier in its life history strategy, being extremely well adapted to the effects of fire with very thick bark, extensive resprouting ability and fast growth rates, combined with very high allocation to root mass, and levels of storage and chemical defence, as well as having very drought tolerant seedlings. Its main weakness as an adult, appears to be its soft wood, which is susceptible to wood borer attack. The perplexing lack of recruitment at some sites in spite of the extraordinary ability of marula seedlings to resprout from an early age, withstand extensive drought, have fast root penetration rates, extremely high root reserve storage and resistance to fire at small stem diameters, combined with high levels of fruit production and low water requirements for germination, is probably due to a combination of the lack of a dense persistent seed bank, high inter-annual variability in fruit production, low germination percentages, high seed and /or seedling predation rates and possibly dispersal of seeds away from suitable habitats. Overall, the unstable population structures observed in the low altitude savannas of South Africa, specifically in the KNP, do not bode well for the future persistence of marula as a dominant canopy tree species. Keywords: elephant, fire, growth, mortality, recruitment, regeneration

No description available.

Aspects of olfactory, auditory, visual and tactile communication were investigated in five Elephantulus species (E. brachyrhynchus, E. edwardii, E. intuft, E. myurus, E. rupestris) and Macroscelides proboscideus, facilitating comparisons among species and genera. The purpose of this study was to determine whether species specific patterns of communication could be identified in the southern African elephant-shrews. Scent gland structure and location was investigated to determine whether species specific differences existed and to relate gland location to marking behaviour. Prominent scent glands were found in the oral angel, foot pads, anogenital region and tail of all elephant-shrew specIes. Marking behaviours such as sandbathing, digging and anal dragging correlated strongly with sent gland location, but no glandular size and/or structural differences were apparent among the different elephant-shrew species. Species specific differences in marking frequencies did exist among the six elephant-shrew taxa, but were unrelated to glandular development. Choice chamber preference tests indicated that Elephantulus species preferred conspecific odours, with males showing higher levels of discrimination than females . Audible vocalizations and footdrumrning were investigated and compared in the sex elephant shrew taxa. Distinct differences were present in the acoustic repertoires of the southern African elephant-shrew species. Footdrumming showed very clear species specific patterns, and footdrumming characteristics were compared with an existing morphological phenogram to derive a possible path of evolution for footdrumming. Visual and tactile communication were investigated by analysis of frequencies and sequences of behavioural acts. A comparison of male-female interactions of the different taxa showed differences in behavioural frequencies both between males and females of a species, and among the different species. Discriminant function analysis showed clear species specific patterns in the visual! tactile signalling systems of southern African elephant-shrews, and this was more clearly defined in males. Elephant-shrews showed higher levels of aggressive behaviour in interspecific encounters, indicating a possible role of aggression as a premating isolating mechanism between species. However, no differences in aggressive behaviour between allopatric and sympatric malefemale interactions could be discerned. Elephant-shrew males showed high frequencies of submissive behaviour in intraspecific encounters, which may be a strategy to reduce aggression in conspecific females. Species specific patterns of behaviour were found to exist in all three modes of communication investigated, and may all act to some extent as premating isolation mechanisms between species. However, many of these patterns are very subtle and it is suggested that a combination of all sensory modalities act together to form each species' signalling system. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1996.

Thesis (M.Sc.(Zoology and Entomology))--University of Pretoria, 2008. / Abstract in English and Afrikaans. Includes bibliographical references.

Thesis (MSc. (Vet. Trop. Diseases))--University of Pretoria, 2003. / Includes bibliographical references.

Thesis (M.S.)--Georgia Southern University, 2008. / "A thesis submitted to the Graduate Faculty of Georgia Southern University in partial fulfillment of the requirements for the degree Master of Science." Directed by Bruce A. Schulte. ETD. Includes bibliographical references (p. 69-88) and appendices.

Thesis (M.S.)--Georgia Southern University, 2009. / "A thesis submitted to the Graduate Faculty of Georgia Southern University in partial fulfillment of the requirements for the degree Master of Science." Directed by Bruce A. Schulte. ETD. Includes bibliographical references (p. 25-45, 64-87) and appendices.

This thesis examines the impacts of human-elephant conflict on human wellbeing and the implications for elephant conservation and management in Trans Mara District, Kenya. The District comprises communal lands bordering the world-famous Masai Mara National Reserve in southwestern Kenya. Trans Mara supports a range of land use types and provides refuge to one of Kenya’s large elephant population comprised of over 3,000 transient and 500 resident animals. This study used interdisciplinary methods to gain insights into the nature and consequences of conflict on the wellbeing of communities living with elephants. In particular, I used a combination of existing wellbeing indices and a set of indicators developed through consultations with local communities in TM to measure impacts of HEC on specific wellbeing domains. The results show that elephants still use the communal lands in Trans Mara but are increasingly restricted to the riverine forest remnants in central Trans Mara. However, there was no evidence of a further decline in the elephant range. Instead, this study points to a shift in elephant range against a background of increasing human settlement, land sub-division and agricultural expansion. The wellbeing of Trans Mara residents comprised eight indicators. Human-elephant conflict negatively affected peoples’ wellbeing, but the impacts were limited to certain dimensions. Elephants affected school-going children within elephant range. Attitudes towards elephants and its conservation in TM were influenced by the location of human residence relative to elephant refuge, diversity of income sources, and age and gender. Finally, conflict mitigation in Trans Mara is still elusive and challenging, but opportunities exist to develop simple and dynamic mitigation tools. The findings of this study have important implications for the future of elephant conservation in the face of competing human needs, both in Trans Mara District and elsewhere in Africa.