No abstract available. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1966.

Chapter 2: Avian frugivores have been somewhat poorly studied with regards to the effects that different fruit sugar types and concentrations have on their digestive efficiencies. Digestion of sugars in equicaloric and equimolar artificial fruit of different sugar types at varying concentrations and molarities were therefore investigated in two relatively large South African frugivores, the Knysna (Tauraco corythaix) and the Purple-crested (Gallirex porphyreolophus) Turaco. Artificial fruits of 6.6, 12.4 and 22% sucrose and glucose respectively and artificial fruits of 0.42, 0.83 and 1.66 mol L-1 sucrose and glucose respectively were used to determine daily food and energy intake, digestive efficiencies and digestive transit times. Digestive transit times of both Turaco species were slower with an increase in sugar concentration and molarity, irrespective of sugar type. Food intake of both Turaco species increased with decreasing concentration and molarity, irrespective of sugar type suggesting compensatory mechanisms for energy requirements. Apparent assimilation efficiencies of both Turaco species ranged from 61.4-90.0% and 60.2-92.4% for equicaloric and equimolar artificial fruit diets respectively. Consequently these two frugivores appear to be tolerant of sugar type and would be expected to select fruits based on energy yields. Future studies of the composition of indigenous forest fruit sugars may give insight into food preferences of the Turaco species and their role as potential seed dispersers of fruiting tree species. Chapter 3: The effects that different fruit sugar types and concentrations have on food preferences of avian frugivores have been relatively poorly studied. Although it has been recently advocated that preference is based on equicaloric energy it is also important to note whether preferences change as energy content changes. Therefore, sugar preferences of equicaloric and equimolar artificial fruit of different sugar types at varying concentrations and molarities were investigated in two relatively large South African frugivores, Knysna (Tauraco corythaix) and Purple-crested (Gallirex porphyreolophus) Turacos. Artificial fruits of 6.6, 12.4 and 22% sucrose and glucose respectively and artificial fruits of 0.42, 0.83 and 1.66 mol L-1 sucrose and glucose respectively were used to determine sugar preferences. Knysna Turacos preferred the sucrose to the glucose equicaloric artificial fruit diet at low concentrations whereas Purple-crested Turacos showed no preference for either diet. Both Turacos species preferred the sucrose equimolar artificial fruit diet to the glucose at low concentrations. At high concentrations neither species showed a preference for either equicaloric or equimolar artificial fruit diets. This suggests that energy requirements influence food preferences more than sugar type and that birds will select fruit that is higher in energy irrespective of sugar type. This complements an earlier study on digestion of sugars at varying concentrations of differing equicaloric and equimolar artificial fruit sugar types. It again emphasizes the need for future studies looking at the composition of indigenous forest fruit sugars in order to obtain insight into the role of these avian frugivores as potential seed dispersers of fruiting tree species. Chapter 4: Avian frugivores may select fruit based on their seed loads and pulp to seed ratios and this may have important implications for their role as seed dispersal agents. Consequently the effect of different seed packaging was investigated in two relatively large South African frugivores, Knysna (Tauraco corythaix) and Purple-crested (Gallirex porphyreolophus) Turacos. Small-seeded artificial fruits containing on average five black plastic beads (2.24 mm diameter) and large-seeded artificial fruits containing one average one single black plastic bead (3.85 mm diameter) were used to investigate transit rates and food preference. Total seed volume in the two fruits was on average approximately equal (29.42 mm3 and 29.88 mm3 for small- and large-seeded fruits, respectively). Bead transit rates ranged from 38-45 min for Knysna Turacos and 36-50 min for Purple-crested Turacos with faster transit rates on the small-seeded diet. Pulp transit rates ranged from 25-39 min for Purple-crested Turacos and 34-40 min for Knysna Turacos. Purple-crested Turacos had significantly shorter pulp transit rates on the large-seeded than the small-seeded diet whereas Knysna Turacos had no significant difference between diets. Knysna Turacos preferred the small-seeded to the large-seeded artificial fruits whereas Purple-crested Turacos showed no preference for either diet. Further studies on avian dispersers will contribute to a greater understanding of their evolutionary relationship with fruiting plants. In particular, future studies establishing suitable seed sizes and volumes for use in determining the effect of seed packaging on larger birds are required as well as studies looking at seed packaging of indigenous forest fruit and the effects of seed packaging on digestion and food preference in indigenous avian frugivores may give insight into the role of avian frugivores as fruit consumers and seed dispersers. Chapter 5: Fleshy-fruited plants and frugivores share a mutualistic relationship with plants offering the frugivores a reward of fleshy fruit pulp in order to disperse their seeds. In return frugivores receive a food source and consequently a source of energy. However all fruits are not equal in terms of available energy and consequently the digestion efficiency of six indigenous tree species was investigated in an avian frugivore, the Knysna Turaco (Tauraco corythaix). It was predicted that the Turacos would process these indigenous fruits efficiently and have fast transit rates and high intake rates irrespective of species. Fruits were fed to the Turacos in separate trials to determine daily food and energy intake, digestive efficiencies and digestive transit times. Digestive transit times of Knysna Turacos (c. 12-28 min) fall within the range of published examples for other frugivorous birds. Apparent assimilation efficiencies of the Turacos ranged from c. 15-84% and were generally lower than those observed in other avian frugivores. Future studies looking at the nutritional composition of indigenous forest fruit may provide insight into the Knysna Turacos digestive efficiency and consequently their food preferences and role as potential seed dispersers of fruiting tree species. Chapter 6: Seed dispersal plays an important role in the persistence, regeneration and maintenance of plant communities. It is therefore not surprising that much attention has been paid to the germination potential of seeds ingested by frugivorous animals. Consequently the aim of this study was to determine what effect ingestion of seeds by Knysna Turacos (Tauraco corythaix) has on the germination rate and germination percentage of indigenous South African tree species. Fruits from twelve tree species were fed to the Turacos in separate trials and seed retention times were determined as it has been suggested that a longer seed retention time may increase germination rates. At the end of each trial, seeds were extracted from excreta of individual birds and planted in trays containing potting soil. Germination was recorded daily until 14 days post of no germination. Knysna Turacos seed retention times were in the range of those obtained by other studies with Ficus sur seeds having the fastest retention times (12.4 ± 0.8 min) and Celtis africana the slowest (34.6 ± 5.6 min). Mean percentage germination of ingested seeds was not significantly different to pulp removed and whole fruit seeds indicating that ingestion by Knysna Turacos did not enhance percentage germination through either seed coat abrasion or pulp removal. Seed ingestion by Knysna Turacos did not influence the rate at which seeds germinated in 75 % of the tree species while it did for ingested F. lutea, F. natalensis and F. sur seeds which germinated significantly sooner than whole fruit seeds. Future studies relating the composition of indigenous forest fruits to food preferences of Knysna Turacos may give insight into their role as potential seed dispersers of indigenous fruiting tree species. Chapter 7: Frugivorous animals play a major role in dispersing tropical, and to a lesser extent, temperate tree species. In order to attract potential seed dispersers, plants generally offer a reward of fleshy fruit pulp. Criteria for fruit choice by avian frugivores are influenced by a number of non-nutritive (e.g. fruit size and colour) factors; and nutritional composition of the fruit. There is a paucity of nutritional composition and other fruit trait data of indigenous South African fruit. This information is necessary in order to determine which frugivores are likely to ingest which fruits and consequently act as potential seed dispersal agents. This information would provide us with an understanding of the inter-relationships between indigenous fruit and frugivores in South Africa. Consequently nutritional composition was investigated in various indigenous fruit species that avian frugivores feed on. Fruits were collected from 38 indigenous tree species found in KwaZulu-Natal afromontane and coastal forests. Pulp was freeze-dried to constant mass and then analyzed for sugar, lipid and protein content; and for water content determination. Fruit width in this study ranged from 4 mm (Searsia rehmanniana and Trema orientalis) to 40 mm (Annona senegalensis, Ficus sur and Xylotheca kraussiana). Of the fruits examined in this study 29% were black and 43% red when ripe. Most (84%) fruit species analysed for sugar content were hexose dominant with 50% being fructose and 34% being glucose dominant. Only 16% of the fruit species analysed were sucrose dominant. Fruits in this study were generally observed to be high (mean: 68.1 ± 3.3%; n = 30) in water content; and low in protein and lipid content respectively (mean: 8.2 ± 0.5%; 9.3 ± 2.2%; n = 30) indicating that these fruits species could be considered as nutrient-dilute. Future studies need to determine the nutritional composition of the remaining indigenous South Africa fruit in order to develop a comprehensive database as well as examining non-nutritive factors. Together this information would play a key role in understanding fruit preferences and consequently seed dispersal and would therefore be useful in developing management plans for forest conservation. Chapter 8: Many seasonal thermoregulation studies have been conducted on Holarctic birds that live in predictable, highly seasonal climates with severe winters. However, relatively few studies have been conducted on their southern hemisphere Afrotropical counterparts that encounter less predictable climates with milder winters. These latter birds are expected to conserve energy in winter by down-regulating their metabolic rates. Therefore in this study, metabolic rate was measured during summer and winter in Knysna Turaco, Tauraco corythaix (Musophagiformes, Musophagidae) (c. 310 g), a non-passerine, in order to test whether there is energy conservation in winter. No overall significant differences in resting metabolic rates over a range of ambient temperatures were observed between winter and summer. However, whole-organism basal metabolic rates were 18.5 % higher (p = 0.005) in winter than in summer (210.83 ± 15.97 vs. 186.70 ± 10.52 O2 h-1). Knysna Turacos had broad thermoneutral zones ranging from 20-28 oC in winter and 10-30 oC in summer. These results suggest that Knysna Turacos show seasonal thermoregulatory responses that represent cold defense rather than energy conservation, which is contrary to what was expected. Keywords: sugar digestion, sugar preference, seed packaging, basal metabolic rate (BMR), resting metabolic rate (RMR), phenotypic flexibility, indigenous fruit, germination percentage, germination rate, fruit sugars, protein, lipids, fruit size, fruit colour, Knysna Turaco, Purple-crested Turaco. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

There is increasing evidence that homeothermy (the maintenance of a high and stable body temperature-Tb) as observed in modern mammals was derived from an ancestral heterothermic (flexible Tb regulation) state. One of main hypotheses for why this occurred is that homeothermy benefits parental care. As such the study of the thermoregulatory physiology during reproduction in an otherwise heterothermic mammal can provide insights into the evolution of homeothermic endothermy in mammals. This thesis presents data collected over three reproductive seasons from one such mammal, the greater hedgehog tenrec (Setifer setosus, Tenrecidae). Flow-through respirometry was used to measure resting metabolism over a range of ambient temperatures (Ta). At low Ta S. setosus demonstrated a high propensity for torpor and highly labile Tb. This high degree of heterothermy was abandoned during reproduction; pregnant and lactating females maintained higher Tb and metabolic rates. Tb obtained from free-ranging animals showed similar trends. Reproductive females had less variability in Tb, whereas non-reproductive females and males had a higher propensity for torpor as well as higher overall Tb lability. These data indicate a larger degree of homeothermy during reproduction. Concurrent with the collection of physiological data, the use of radio-transmitters, implanted into the peritoneal cavity along with the temperature data-loggers, allowed for novel observations on the life-history of this little-studied species. The most striking finding was that S. setosus demonstrates an exceptional capacity to assimilate energy. In the short active season males showed high levels of activity and occupied home ranges larger than predicted for their body size. Females, in addition to maintaining a higher degree of homeothermy, can have up to three litters per year. Over this same time period individuals of both sex double their body mass in preparation for hibernation. Such high energetic outputs are thought to be incompatible with the low basal metabolic rates which this species displays. An explanation of this incongruity can be found in the high Ta at the study site, which negated most thermoregulatory costs. In reproductive females, the fitness benefits of small increments in homeothermy seem to be offset by the relatively low fitness costs involved in minimal thermoregulatory energy demands. Homeothermy during reproduction is therefore likely to have been a first step in the progressive evolution from heterothermic to homeothermic endothermy in mammals. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2014.

Black Sparrowhawks (Accipiter melanoleucus) are a medium-sized raptor found across much of sub-Saharan Africa. Within South Africa their distribution has historically been across most of the east with no distribution across the west of the country. Recently, however, the Black Sparrowhawks of South Africa appear to have undergone a range shift with their range expanding into the west, and in particular into the Cape Peninsula. Much of their new range appears to be into urban and peri-urban areas. The aim of this thesis was to analyse reproductive characteristics as well as range changes and dynamics of Black Sparrowhawks along a rural urban gradient in KwaZulu-Natal. In particular what influences range changes, reproductive success, nest site selection and home range of Black Sparrowhawks was determined. Urbanisation is one of the fastest changing and growing land uses worldwide, generally impacting negatively on fauna and flora community composition, species density and species ranges. Despite this the Black Sparrowhawk is one raptor species that appears to be thriving in urban habitats and has seemingly undergone recent range expansion, largely into urban areas. It was investigated whether Black Sparrowhawks have changed their range over recent years in South Africa. This was determined using data from both of the South African Bird Atlas Projects (SABAP1 and 2) and showed a definite shift and increase in the Black Sparrowhawk distribution. Black Sparrowhawk habitat use in terms of indigenous forest, commercial plantations and urban areas in South Africa were compared. Data from the SABAP2 project was analysed together with land cover types using generalized linear models with binomial errors and a logit link function. These results showed a positive relationship between the probability of encountering a Black Sparrowhawk in areas with tree plantations and in urban areas. However, no significant relationship was found between the probabilities of encountering a Black Sparrowhawk in areas of indigenous forest. Black Sparrowhawks appear to be a common urban species, however it seems they are limited to certain land use areas and this could affect their persistence in the future, particularly in urban areas. Black Sparrowhawks appear to be thriving in urban habitats. Typically known as a shy forest species, they are now frequently seen and heard in urban areas in South Africa during the breeding season. The spatial and environmental factors that influence Black Sparrowhawk nesting sites in urban and peri-urban areas were investigated in KwaZulu-Natal. Our data suggest that Black Sparrowhawks appear to be very selective in nest site selection particularly with respect to nest tree species, tree and nest height, area of greenspace’ surrounding the nest, and associations with water sources, roads and buildings. Black Sparrowhawks show a significant preference for a particular tree height class (20 – 29 m) as well as a significant preference for a specific nest height class (10 – 19 m). Similarly the preference of distance classes to the nearest water sources, buildings and roads all showed a significant selection by Black Sparrowhawks. Nest sites appear to be associated with the alien Eucalyptus sp. Due to ever changing urban habitats and human altered landscapes, as well as the removal of alien tree stands within urban areas, the availability of nest sites and foraging habitats may decline. It is therefore important that we understand the specific needs of such a species in order to monitor their success and initiate management programmes where necessary for their persistence. Black Sparrowhawks appear to be increasing in human altered landscapes, however little is known about their breeding success and characteristics. Consequently their reproductive and resource requirements and trends, as well as overall reproductive success along a rural/peri-urban urban gradient in KwaZulu-Natal were investigated. Over the 2011 and 2012 Black Sparrowhawk breeding seasons the majority of successful nests raised two nestlings. In 2011 Black Sparrowhawk nests had a success rate of 74 % while the success in 2012 was only 41 % which yielded a higher number of unsuccessful breeding attempts, these results were determined by nest observations during the breeding seasons. Nest preparation was done predominantly by the male with incubation then predominantly by the female. An increase in fresh leaf material being brought to the nest as the chick aged suggested that this is more likely due to parasite control rather than showing nest occupancy as has been previously speculated. There is little known about the movements and home range of Black Sparrowhawks, particularly in an urban environment. Consequently the home ranges of both an adult breeding female and a juvenile male Black Sparrowhawk were determined during the 2012 breeding season in Durban, KwaZulu-Natal. Transmitters were attached to the individuals recording their locations at regular intervals between 6h00 and 18h00. An adult female was trapped and had the transmitter placed approximately a week prior to the chicks fledging the nest. Her breeding season home range remained within close proximity to the nest. A juvenile male from the same nest was trapped approximately two weeks after fledging at the point of starting to learn to hunt independently. The data produced a minimum convex polygon (MCP) for the adult female of 0.0025 km2 while the young male remained within an MCP of 0.4554 km2. This pilot study has allowed us to determine a viable method which can be used to obtain Black Sparrowhawk home range information. This method can now be applied to numerous pairs within a population to determine home range overlap, territoriality as well as post natal dispersal. Despite the fact that Black Sparrowhawks appear to be increasing in human altered landscapes and expanding their range, further studies should be built on this pilot study in order to identify the degree of threat this species faces. This will allow for long term management plans to be establish which will facilitate their persistence in South Africa. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2014.

Following preliminary observations in 1975 the Lake Kariba Fisheries Research Institute implemented a research program in March 1976 to investigate various aspects of the biology and population dynamics of the mussel crop of Lake Kariba, with a view to greater understanding of their status in the lake, and establishing a basis for management, if required. Aspects investigated were densities, distribution, species composition, predation by fish, reproduction, age and growth, gross biochemical composition and crude production rates. The mussel community comprised four species, a small pill clam, Corbicula africana, and three mussels, Caelatura mossarnbicensis, Aspatharia wahlbergi and Mutela dubia. Only the latter three were studied. Mussel beds occupied all the gently shelving cleared and uncleared areas, and the bulk of the populations occurred from 3 m - 9 m depth, but extending to 11 m. Predation by fish was found to be extremely low. The reproduction study showed two species bred all year C. mossambicensis and M. dubia, whereas A. wahlbergi bred seasonally during the rainy season. The two year-round breeders were repetitive spawners, capable of breeding several times a year. Indications are that A. wahlbergi is essentially a fluviatile species, with a life cycle adapted to taking advantage of riverine conditions. Sex ratios in all three species were approximately 1 : 1 , with females predominating slightly. Fecundity in one species, C. mossambicensis, was investigated. The complete parasitic cycle of M. dubia was elucidated and found to be similar to that of M. bourguignati, as described by Fryer (1961). Host species were noted amongst the cichlid and mormyrid families, and the conclusion drawn that the species is not host specific. various aspects of the life-cycles of the other two species were noted, but complete life-cycles were not successfully elucidated. population composition according to age showed the most common species, c. mossambicensis, to be comprised mainly of 2 - 5 year-old individuals, indicating a young and vigorous population. Juvenile pre-adult mussels were very scarce. In the population of A. wahlbergi, older mussels formed a greater proportion of the biomass than in the population of c. mossambicensis, and young were also scarce. M. dubia were not recorded in sufficiently large numbers to estimate age composition accurately. The production rate (whole wet mass) of the most common species, c. mossambicensis, was calculated to be 2,45 kg ha¯¹ day¯¹ in the sanyati East cleared area (30,5 km²), while the overall production rate of all three species was calculated to be 3,34 kg ha¯¹ day¯¹. Calorific values of all three species were obtained, while gross body composition in terms of water, fat, protein, ash and amino acid composition were determined. The ash component of A. wahlbergi was analysed. The Lake Kariba results were supplemented by a follow-up study of the composition of the mussel population of a eutrophic, highveld dam, Lake McIlwaine, in 1978/1979. This much smaller lake was populated by only two mussel species, M. dubia and C. mossambicensis, although A. wahlbergi and Unio caffer were recorded in the riverine upper reaches. Observations on seasonal breeding of the two lake species were made. A detailed study on the draw down zone of a gently shelving beach showed that at the time the extreme shallows had been dominated by C. mossambicensis, whereas from a depth of approximately 1,6 m M. dubia dominated very significantly. Fulling lake level was found to trigger off migratory responses, thus placing a proportion of individuals in deeper water and improving chances of survival. The mussel composition of Lake Kariba and Lake McIlwaine was considered in conjunction with preliminary observations of mussel distribution a nd composition in other water bodies, and some inferences drawn regarding the ecological factors which appear to influence the composition and diversity of the mussel fauna in rivers and lakes. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1980.

This study investigated aspects of the breeding biology, ecophysiology, morphology, over-wintering and population dynamics of the pre-imaginal stages of members of the Anopheles gambiae complex in northern Natal, South Africa, Investigation of the breeding biology, concentrated on breeding site utilisation by the different members of the Anopheles gambiae complex. Surveillance personnel were unable to locate the breeding sites of Anopheles arabiensis and postulated that location and description of these would offer a unique opportunity for control. The difficulty in locating the breeding sites of An. arabiensis at certain localities was found to be a product of their low density, presumably as a result of the intra-domiciliary, residual insecticide spray programme. The effect of temperature on larval physiology and adult morphology was investigated. terms of their implications Anopheles gambiae complex. The findings are discussed in for anopheline taxonomy and the The effect of temperature on larval growth rates was investigated in both the field and laboratory. The finding of this part of the study indicate that the larval stages play an important role in the over-wintering of populations within the region. The control implications of these findings and winter breeding site localisation are discussed. A theory for the so called 'late season transmission i.e. Apri-May, within the province and southern Africa is proposed. The population dynamics of An. merus were investigated, together with the effect of abiotic factors such as temperature, salinity and rainfall. The effect of sampling bias due to factors such as behavioural avoidance were studied. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1991.

Up until 1969 Nile Crocodiles (Crocodylus niloticus) were considered as vermin in South Africa and were actively persecuted throughout the country. In an effort to re-establish viable populations within protected areas in Zululand a restocking program was initiated in the late 1960‟s and early 1970‟s. Ndumo Game Reserve (NGR) in north eastern KwaZulu-Natal was one of the reserves involved in the restocking program and the Nile Crocodile population in the reserve increased from a minimum absolute abundance of 348 (SE ± 3.39; N = 3) in the early 1970‟s to a minimum absolute abundance of 992 (SE ± 58.70; N = 4) in the 1990‟s. However, in recent years there has been some concern that the NGR Nile Crocodile population may be on the decline, initiating the current investigation into the ecology and conservation of the NGR population. We examined changes in relative abundance using aerial survey data from 1971 – 2009. The precision and accuracy of population estimates was affected by water level, season, aircraft type and the use of different observers. A correction factor was applied to survey data and the current NGR Nile Crocodile population is estimated at an absolute abundance of 846 (± 263). Distribution data from the aerial surveys were also used to examine habitat use over the last 40 years and revealed that Nile Crocodiles were not evenly distributed in NGR and that crocodiles favoured the Phongola over the Usuthu floodplain systems. NGR is characterised by a floodplain mosaic landscape and crocodile distributions between the various habitat patches were influenced by landscape physiognomy and composition as well as connectivity and corridor quality. Anthropogenic disturbances influenced the functionality of the floodplain landscape negatively with impacts on habitat use and connectivity. To quantify the effects of environmental conditions on crocodile habitat use we conducted 40 diurnal counts at Lake Nyamithi between 2009 and 2012 and related changes in crocodile numbers here to temperature, rainfall and water level. Crocodile density in Lake Nyamithi was significantly and negatively related to average maximum ambient temperature and numbers increased in the lake over the cool, dry winter season. Water level and rainfall had strong but not significant (p >0.05) negative influence on crocodile density in Lake Nyamithi. Environmental variables influenced different size class of Nile Crocodiles differently and the density of crocodiles in the 1.5 – 2.5 m Total Length (TL) size class were significantly influenced by rainfall and average minimum monthly temperature. Movement patterns of 49 Nile Crocodiles between 202 – 472 cm total length (TL) were followed over 18 months using mark-resight (n = 36), radio (n = 10) and satellite (n = 3) telemetry. The duration of radio transmitter attachment (131 days, SE ± 11.35) was significantly related to TL and reproductive status. Satellite transmitters stopped functioning after 15 (SE ± 12.53) days and home range was calculated for 7 crocodiles ranging in size from 202 cm TL – 358 cm TL. Sub-adults (1.5 - 2.5 m TL) occupied smaller, more localized home ranges than adults (> 2.5 m TL). Home ranges overlapped extensively suggesting that territoriality, if present, did not cause Nile Crocodiles to maintain spatially discrete home ranges in NGR during the dry season. A single large scale migration event occurs every year between October and November whereby the majority of the NGR crocodile population leaves the reserve and enters the Rio Maputo floodplain in adjacent Mozambique and only return in April/May. Nesting effort (19 – 21 %) in NGR was comparable to other populations of Nile Crocodile in southern Africa. Nests are completely destroyed by floods once every 10 years and predation rates may range from 20 – 86 % per year. In addition to aerial surveys, nesting surveys and movement studies crocodiles (n = 103) were caught opportunistically to collect demographic data on population structure. The population structure of Nile Crocodiles in NGR is currently skewed towards sub-adults and adults suggesting an aging population that may decline naturally in the future. This could be due to low recruitment levels in NGR that are not able to sustain the artificially high population size created by the restocking program. Sex ratios were skewed towards females in the juvenile and sub-adult size classes and towards males in the adult size class while the overall sex ratio was even between males and females. It is predicted that the NGR Nile Crocodile population will decline in the future and that this decline should be considered as a natural process. However, the rate of decline will be accelerated at an unnatural speed and to an unnatural extent due to poaching, uncontrolled harvesting and destruction of nesting habitat within NGR. Based on the findings of the current study, management recommendations for the conservation of the combined NGR – Rio Maputo Nile Crocodile population were made. It is important that further research takes place in the Rio Maputo floodplain in Mozambique to better quantify the nesting ecology of the NGR Nile Crocodile population and to identify possible threats facing Nile Crocodiles in this region. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.

The Maputaland-Pondoland-Albany (MPA) hotspot, as is the case of all such global biodiversity hotspots, has primarily been recognised based on its high floristic endemism and delimited intuitively. Boundaries of global biodiversity hotspots have seldom been empirically tested in terms of species distribution patterns and only a few have been examined for patterns of animal endemism. This thesis presents the results of a zoogeographical study of all five major vertebrate groups and selected invertebrate groups in south-eastern Africa, refining the delimitation of the MPA hotspot and identifying areas and centres of endemism within and around it. It also provides zoogeographical regionalisation schemata for the whole of south-eastern Africa. The study employed methods of, (a) preliminary qualitative identification of “Endemic Vertebrate Distributions”, (b) phenetic clustering of operational geographical units based on species incidence matrices, using the Jaccard’s coefficient of similarity and the Unweighted Pair-Group Method using Arithmetic means (UPGMA) clustering algorithm, (c) Parsimony Analysis of Endemicity, and (d) ArcGIS-based mapping of various measures of endemism (e.g. narrow endemism and weighted endemism). The results reveal that the MPA hotspot, though defined so due to its exceptional floristic endemism, is a hotspot for the endemism of animals too, especially for the herpetofauna and invertebrate groups like the velvet worms, land snails and many others. But the current boundary of the hotspot is arbitrarily defined and not exactly matching the patterns of animal endemism (and, likely, neither those in plants). Hence, a greater Maputaland-Pondoland-Albany (GMPA) region of animal endemism is proposed as a broad priority region of conservation concern, while centres of endemism within the GMPA are identified and patterns of quantitative measures of endemism are mapped. The study also proposes a zoogeographical regionalisation placing the GMPA and Highveld regions at the province rank in the global zoogeographical hierarchy, within the south east African dominion, also describing zoogeographical districts and assemblages nested within each. Results from the vertebrate and invertebrate analyses reveals the possibility of a common zoogeographical regionalisation for south-eastern Africa. The study emphasises the importance of quantitative biogeographical methodologies in conservation biogeography, in addition to their uses in the theoretical/descriptive biogeography. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2013.

Studies In other parts of the world have proved that turbidity affects aquatic life and work In Australia and North America has shown that the distribution of some fish species may be determined by the level of turbidity present. This, coupled with the fact that: (i) Natal estuaries are important as nursery areas for the juveniles of many marine fish species, (ii) the estuaries exhibit a wide range of turbidities and (iii) little was known of the effects of turbidity on the fish populations in estuaries, led to this study being undertaken. Turbidity and its effects on fish distribution In Natal estuaries was investigated from January 1980 to June 1983. Lake St. Lucia, which is predominantly turbid but also has clear water areas, was the main study area. Six other estuarine systems sampled were chosen to cover a wide range of estuarine types and turbidities. Field sampling was undertaken to determine which species were present under different turbidities, simultaneously physical factors which were potentially affecting fish distribution were also monitored. In addition to this, laboratory equipment which enabled a turbidity gradient to be established In a choice chamber tank was used to test the turbidity preferences of 10 common estuarine species for which field data were available. These tests allowed the elimination of all physical factors except turbidity. Of the physical parameters monitored In the field, turbidity, temperature and food availability In the benthos, were determined as being important In affecting fish distribution within estauries. However, comparison of fish distribution data for twenty species, with these factors showed that turbidity was exerting the major influence. It was also found that fish species occurred In one of five groups, inhabiting either clear, 'clear to partially turbid', intermediate or turbid waters or they were indifferrent to turbidity. Laboratory results for eight of ten species tested showed significant aoreement with the field data. The results of this study have shown that turbidity is the most important factor determining the distribution of juvenile marine fish In estuaries and that the greatest number of species are present in , waters which are not clear. The attraction to and presence in such systems appears to be related to the fact that turbid estuaries 'provide protection from fish and bird predators while also acting to reduce intraspecific predation. Of factors attracting juvenile fish into estuaries, turbidity is probably the single most important acting in this respect. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1984.

Eremitalpa granti namibensis is a small blind subterranean insectivore (Chrysochloridae) endemic to the Namib Desert sand dunes. This study of the biology and ecology of the Namib mole assesses its adaptive strategies for survival in a harsh environment. Major areas of study include feeding ecology, movement patterns, home range, activity, thermoregulation and water metabolism. Diet of free-living moles was assessed through stomach content analysis while qualitative and quantitative descriptions of surface foraging paths related searching behaviour to resource abundance and distribution. Moles opportunistically fed on termites, a sedentary prey resource occurring in patches of high concentrations while non-random surface locomotion minimised foraging costs. Population density and home range utilisation were studied by following surface trails and capture mark and recapture. Population density was low but stable and home range size large. No permanent nests or burrows were found while the pattern of home range utilisation was nomadic but circumscribed. Although ranges overlapped, a system of mutual avoidance limited encounters with neighbouring animals. Activity phasing was examined in the field and in the laboratory. Free-living moles were almost exclusively nocturnal while captive moles were active day and night. These findings are discussed in relation to prey availability, predator pressure and avoidance of diurnal extremes. Light and temperature appeared to be important cues for daily onset and cessation of activity. Aspects of thermoregulation examined under laboratory and field conditions revealed high thermal conductance, a low basal metabolic rate and poor thermoregulatory abilities. Factors suggested to have selected for these traits are the gaseous regime of the sand in which moles burrow and the need to minimise energy expenditure in an energy sparse environment. Laboratory and field studies employing isotopic dilution of energy and water methods e xamined the metabolism ability of moles to survive on an insect diet without drinking water. Water independence was achieved through efficient renal function while low rates of energy usage and torpor were further effective in reducing overall water requirements. In summation, a broad overview of adaptive radiation in Namib moles compared to other subterranean mammals is discussed. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1989.