Thesis (M.Sc. (Zoology & Entomology)) - Rhodes University, 2007.

Arid and semi arid environments are characterised by extreme fluctuations in temperature and low rainfall which present significant challenges to the animals inhabiting these areas. Mammals, such as aardvarks (Orycteropus afer, Pallas 1766), excavate burrows in order to avoid predators and climatic extremes and are termed “ecosystem engineers” as they physically modify their environment and in doing so create new habitats and alter the availability of resources to other species. In this study I assessed the microhabitat conditions (maximum and minimum temperature, relative humidity and seed abundance) of aardvark burrows in relation to paired control sites. In addition, I evaluated the use of aardvark burrows by other vertebrate and invertebrate species and investigated the impact of aardvark burrow mounds on landscape scale floristic diversity. Maximum temperatures were significantly lower (p < 0.05) and minimum temperatures and midday humidity were significantly higher (p < 0.05) inside the burrows at the three study sites, Kwandwe Private Game Reserve (Kwandwe), Mountain Zebra National Park (MZNP) and Tswalu Kalahari Reserve (Tswalu). There were no significant differences between the concentration of seeds, the average numbers of unique individual small mammals, trap success or small mammal species richness recorded inside the burrows compared to outside (p > 0.05). At all three sites, small mammal species diversity was higher in the burrows but this result was also not significant (p > 0.05 for all). Trap success and the number of individuals captured was higher at Tswalu than the other two sites (p < 0.05 for both). The different methods used in this study revealed a total of 25 mammal, seven bird, one amphibian and six reptile species utilising aardvark burrows. There were significant differences in insect community assemblages between the burrows and open control areas at Kwandwe and Tswalu (p < 0.05 for both) but not at MZNP (p > 0.05). The parasitic guild was more prominent inside the burrows than outside but their abundance was not as high as anticipated, possibly due to the placement of traps closer to the burrow entrances than the sleeping chambers. The complex structure of the burrows prevented the placement of traps in close proximity to the sleeping chambers. As expected, the amount of bare earth was significantly higher on active and recently abandoned burrow mounds compared to the old burrow mounds and reference plots at all three sites (p < 0.05 for all), with the exception of the active burrows at Tswalu. Overall, the different plot types were characterised by significantly different plant communities during all the seasons at MZNP, during three of the seasons at Kwandwe and only during winter at Tswalu. The total species richness recorded on the reference plots was higher than on the burrow mounds at all three sites. However, species diversity on the reference plots was not significantly higher than the burrows at any of the sites (p > 0.05 for all sites). Although the results were not significant, the overall species diversity at a site level was greater than the reference patches at Kwandwe and Tswalu (p > 0.05 for both). Aardvarks fulfil the criteria of a significant ecosystem engineer and their presence in arid and semi-arid environments is likely to be critical to the survival of other individual organisms and species, particularly when alternative burrowing animals are either absent or restricted in their activities. Thus, aardvark populations should be considered a conservation priority in arid and semi-arid ecosystems.

Thesis (MSc. (Veterinary Tropical Diseases))--University of Pretoria, 1999. / Also available in print format.

The seasonal diet, feeding patterns, feeding selection and habitat selectivity of the aardvark were determined during summer and winter at Tussen die Riviere Nature Reserve in the southern Free State. Pitfall trapping, dig sampling and quadrat sampling were used to determine the resource base of three habitats in the summer and winter of 1998. A total of 44 ant species of 5 sub families and 17 genera, and two termite species of two sub families were recorded. Pitfall trapping was the most successful technique, followed by quadrat sampling (51.1%) and finally, dig sampling (48.8%). Abundance and diversity was higher during summer than winter. Monomorium albopilosum was the most abundant species in all habitats in winter, whilst Anoplolepis custodiens was the most abundant in summer. The grassland habitat yielded the highest abundance and diversity, followed by the steep slope and riverine areas. Seasonal diet and foraging patterns were determined through faecal analysis and observation of four habituated aardvarks. The Formicidae were more important than the Isoptera in both seasons. The feeding of the aardvark was highly selective, only 28.8% of the available species having been utilised. Prey selection was found to be most highly correlated with prey size, prey abundance, prey mobility, and prey calorific value. Aardvarks were highly selective in their habitat utilisation. The vast majority of feeds were made in the grassland areas where prey abundance was greatest, compared to negligible numbers of prey in the rocky steep slopes and no prey in the riverine areas due to periodic flooding. / Dissertation (MSc (Veterinary Tropical Diseases)--University of Pretoria, 1999. / Veterinary Tropical Diseases / unrestricted

Increasing urbanization is often accompanied by problematic changes in watershed hydrology. Decreasing surface permeability can lead to increased overland flow volumes, which may spread surficial contaminants and increase the strain on municipal stormwater infrastructure. This study examines a mixed-use property in the Proctor Creek watershed in Atlanta, Georgia, to better understand how land-management practices influence soil overland flow potential. Field saturated hydraulic conductivity (Kfs) measurements were collected from soils 1) subjected to compaction, 2) in urban agricultural use, and 3) under common lawn maintenance. Mean values were 9.1E-7 cm/s, 2.2E-4 cm/s, and 9.0E-6 cm/s respectively. Measurements were collected in-situ with the use of the Aardvark constant-head permeameter. Statistical analyses indicated a substantial difference in Kfs based on land-management practices and that urban farming can increase soil Kfs and limit overland flow. Additional analysis revealed no significant difference in grain-size distributions suggesting land-management practices controlled Kfs, not soil texture.

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No description available.