Viverrids are small carnivores that achieve high species richness throughout their range. This study investigated the ecology and resource partitioning of five members of this family (Genetta tigrina, Herpestes ichneumon, Galerella sanguinea, Atilax paludinosus and Mungos mungo) that coexist in Vernon Crookes Nature Reserve on the south coast of Natal, South Africa. Emphasis was placed on differences and similarities within this assemblage. Diets of the viverrids were determined by scat analysis and prey abundance was revealed by means of a monthly trapping programme. The spatial ecology of the assemblage was assessed using radio-tracking and habitat utilisation was compared with habitat availability. The activity regimens of viverrids were also determined from radio-tracking. Consideration of all three major niche dimensions (food, habitat and time) revealed important differences within this assemblage. Each species used different resources, along at least one niche axis, from other members in the assemblage. Consequently, the three niche dimensions segregated all five species. These differences may reduce interactions and facilitate coexistence. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1988.

No abstract available. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

The taxonomy and biogeography of the southern African pheasant shell fauna are poorly known. Thirty–one nominal taxa referable to Phasianelloidea have been described or recorded in this region, but no systematic revision of these has ever been undertaken. Morphological evidence suggests that 16 taxa represent valid species, 13 are synonyms and two represent incorrect identifications. DNA sequence data from mitochondrial COI and 16S markers are used to assess the validity of the described nominal southern African Tricolia species. Phylogenetic analyses recovered seven distinct clades. Tricolia adusta, T. elongata, T. formosa, T. kochii, T. saxatilis and T. neritina were recovered as distinct species. Tricolia africana and T. capensis are genetically indistinguishable. However, morphological characters of the shell are clearly diagnosable. This could be due to incomplete sorting (ancestral polymorphism) reflecting recent speciation with rapid morphological and ecological divergence co–incident with geographical separation. Similarly, there is little genetic differentiation between T. bicarinata, T. insignis and T. kraussi. In this case the similarity is also supported by morphological data as the three species are conchologically close with intergrading shell characters, and might even be one species exhibiting ecogeographic variation in shell form. Monophyly of the southern African Tricolia species is not supported as well as the relationship between these and the European Tricolia pullus. In the last chapter a molecular phylogeny based on sequence data from mtDNA (COI and 16S), nuclear (18S and 28S) and the combined data (COI, 16S, 18S and 28S) is presented for the Phasianelloidea. Bayesian inference analyses performed on the combined data support the monophyly of Tricolia sensu stricto, Eulithidium and Phasianella. Tricolia sensu lato is not monophyletic, as its southern Australian and Indo–West Pacific species do not cluster with its southern African and Eastern Atlantic representatives. The position of Hiloa and Gabrielona within the Phasianelloidea is unresolved. Phylogenetic reconstructions using bayesian inference support monophyly of the Phasianelloidea. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

ln this study the exploitation of the fish fauna of the Kosi estuarine system by man and natural predators is described and estimates made of the off-take and its species composition. The most important human exploitation, that by the traditional Zulu fish traps, was monitored over a four year period and the data collected were used to give an insight into the marine fish populations of the system. All the physical parameters, which it was thought could influence the migrations of fish, were monitored and correlations between these and the daily and monthly fish trap catches were used to interpret fish movements into and out of the system. Reasons for the annual migrations and day to day movements of fish were investigated. In order to establish relative off-takes by local fishermen and sport anglers fish were tagged inside the system and the recovery rates by the various fishing methods were used to calculate estimates of the percentage off-takes of these principal human exploitation methods. These data were also used to obtain estimates of the population sizes of the major marine fish species inside the system. Catch data were used to indicate the levels of estuarine dependence of these species. Where possible comparable data from other areas were used to indicate whether or not similar trends in catch abundance were obvious. The ecological and economic importance of the Kosi system is discussed and its value to the local inhabitants stressed. Competition between the various fishing techniques is described and recommendations are made concerning future fish exploitation. Natural predation rates are also discussed and levels compared with those of other systems. The fish food resources of the systems are considered in the light of recently declining salinities, destruction of swamp forests and increasing numbers of hippopotami. The implications of these changing factors are discussed as is their impact on the Kosi Bay fisheries. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1986.

The limited availability of land to forestry and the ensuing emphasis on intensive silviculture, developed a renewed interest in soil pests in the establishment of plantations. Ten field trials were planted over three seasons to determine the mortality factors influencing the establishment of commercial eucalypt and black wattle plantations in the Natal Midlands, and simultaneously, to investigate the chemical control of the soil pest component. A complex of indigenous soil pests contribute to an average 22,9 % failure of Acacia mearnsii and Eucalyptus grandis seedlings from reaching full establishment. This pest complex, which includes termites, whitegrubs, cutworms, tipulid larvae, wireworms, millipedes and nematodes, was responsible for an average 12,3 % of the failure of the plantings to establish. In the absence of termites, in shallow humic soils, whitegrubs followed by cutworms were the most frequent and economically important pests. Eucalypts are more susceptible than wattle seedlings to whitegrub damage when planted in marginal sites. Seedlings in the summer rainfall region were most susceptible to whitegrub damage from December to April; and to cutworm damage during the first two months after planting. An average of 398 hectares was annually damaged by whitegrubs and cutworms. The total annual loss in planting costs and the additional costs of blanking over the three year study period were 1,22 and 2,65 million rands respectively. Existing non-chemical control applicable to woodlot forestry is reported. Chemical control as one of the options in the management of whitegrubs and cutworms was evaluated. The controlled release formulations of carbosulfan 10% and chlorpyrifos 10% at 1,0 g active ingredient/tree (a.i./tree), gamma BRC 0,6% dust at 0,06 g a.i./tree and the synthetic pyrethroid deltamethrin 5 % SC at 0,025 g a.i./tree were persistent and effective in controlling whitegrubs, even when applied early in the planting season. Deltamethrin 5 % SC at 0,025 g a.i./tree was also successful in controlling cutworms. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1995.

Savannah baboons (Papio cynocephalus) have been studied in numerous sites throughout Africa. They have been found to display a wide variety of foraging and feeding behaviours. The aim of this study was to describe and quantify these for a troop in a southern woodland habitat and to determine what factors influence these in order to understand the choices made by baboons. This was done within an optimal foraging framework. The study included the development of random walk and optimal foraging simulation models of day journeys and a comparison of feeding and foraging before and after the troop divided into two daughter troops. The troop lived in a complex mosaic of habitat types with a high tree density. The troop's foraging strategies were found to be consistent with being time minimizers. Distance from the centre of the home range and distance from the nearest sleeping site had the most significant effect on utilisation of the home range. The effect of food availability on habitat use could only be distinguished by the use of simulation models. Comparison of food encountered by the troop and that encountered in the simulations demonstrated that the troop did better than could be expected if the day journey routes were random. The troop's results approximated those of a stochastic short-term optimisation model. The troop's diet consisted of a higher proportion of fruit than previous studies. The troop distinguished between commonly utilised foods and those only occasionally used on the basis of protein/fibre ratio, however food preference between main foods was not correlated with protein/fibre ratio. Any combination of the main foods would fulfil their protein requirement. Evidence is given that, without protein being limmiting, the troop's selection amongst the main foods is based on carbohydrate content. After troop fission the daughter troops had shorter day journeys, spent less time walking, more time socialising resting. They also spent more time in food-rich habitats and were more selective in their diet. These results reinforce the important influence in group size and suggest that troop fission may be seen as a time-minimising strategy. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1994.

Thesis (MSc)-- University of Stellenbosch, 1954 / Published in the Annals of the University of Stellenbosch, Volume 31, Section A, No.1 (1955) / ENGLISH ABSTRACT: The pelvic girdles of the two anuran genera Ascaphus and Leiopelma of the family Ascaphidae are very similar. Attached to them by cartilage (or connective tissue in some Ascaphus specimens) is a cartilaginous, in Leiopelmu somewhat ossified, epibubis. In Ascaphu8, as in Xenopus, the epipubis originates from two Anlages, and its muscles are also paired in the Ascaphidae, while in Xenopus only one is present, although this also appears to originate (rom two muscles. The cloaca extends behind the pelvic girdle in both sexes in Al:lcaphus, and it is supported by two rods consisting of strong connective tissue (Faserknochen?). These rods are attached to the ventral surface of the pelvic girdle, in the female closely, in the male by means of tendons. Between the rods and the epipubis a broad tendinous band extends, which is thick in the male; in the latter the mm. compressores cloacae have their origins posteriorly on the rods, while in the female the rods are completely imbedded in these muscles posteriorly. In the female particularly there are transverse muscle fibres which are not striped although probably derived from the mm. compressorcs cloacae. Behind the pelvic girdle there is cavernous tissue in both layers of the tunica muscularis, and ventrally it covers the mm. eompressores cloacae. The circular and longitudinal muscle layers are poste riorly separated by gliding planes. The cloaca is supplied by branches of the a. mcsenterica posterior and the au. pudendae anteriores, and is drained by the vv. pudendae and a small medial v. eaudalis. The cloaca is innervated dorsally by the plexus ischio·coccygeus and ventrally by a branch of the n.ischiadicus (the n. pudendus). The cloaca of the male serves as a copulatory organ. There is internal fertilization. / No Afrikaans abstract available. / The copy we received from the author were pages individually scanned in as JPEG images.

Thesis (MSc)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Agricultural environments are usually contaminated with mixtures of antropogenically introduced chemicals as a result of pesticide spraying, which can affect beneficial, nontarget soil invertebrates, such as earthworms negatively. Most studies on mixture toxicity have focused on interactions of chemicals with similar structures and mechanisms. However, chemical mixtures may occur as conglomerates of diverse structures and toxicological mechanisms in the environment. This study was aimed at assessing the effects of pesticides singly, and in a mixture, on earthworms, using lifecycle parameters (growth and reproduction) and biomarkers (neutral red retention (NRR) assay and acetylcholinesterase (AChE) inhibition) as endpoints. Thus, to determine whether any interactions occurred between the pesticides as shown by the measured endpoints. Another aim was to validate the use of the chosen biomarkers for assessing mixture toxicity. The pesticides used were from three groups: organophosphates, heavy metal-containing pesticides and pyrethroids. From these three groups, four of the most commonly used pesticides in the orchards and vineyards of the Western Cape, South Africa, were chosen, namely chlorpyrifos (organophosphate), azinphos-methyl (organophosphate), copper oxychloride (heavy metal-containing fungicide) and cypermethrin (pyrethroid). Earthworms were exposed in the laboratory to a range of concentrations of chlorpyrifos and copper oxychloride singly, and in 1:1 mixtures of these pesticides in artificial soil, for four weeks. After the exposure period, the biomass change was determined as measure of growth, and cocoon production, hatching success and number of hatchlings per cocoon were determined as measures of reproduction. Growth (biomass change) and reproduction (cocoon production) were affected by the highest concentration treatment (20mg/kg) of chlorpyrifos, but copper oxychloride and the mixture of the two pesticides showed no observable effects on lifecycle parameters. Dose related effects on NRR times were however determined for both pesticides and the mixture. Dose related effects on AChE activity were found for chlopyrifos and the mixture of the two pesticides, but not for copper oxychloride. Short-term exposures (48 hours) of earthworms to the following pesticides in artificial groundwater: chlorpyrifos, copper oxychloride, azinphos-methyl, cypermethrin, chlorpyrifos-copper oxychloride, chlorpyrifos -azinphos-methyl and chlorpyrifos-cypermethrin, were done followed by the determination of AChE inhibition. Dose related effects were exhibited on the AChE activity of earthworms exposed to chlorpyrifos, a mixture of chlorpyrifos and copper oxychloride, azinphos-methyl, and a mixture of azinphos-methyl and chlorpyrifos. Copper oxychloride, cypermethrin and the mixture of chlorpyrifos and cypermethrin had no effect on AChE activity. Earthworms died at the highest exposure concentration of the mixture of chlopyrifos and cypermethrin. Results have shown that although the pesticides did not cause observable effects on lifecycle parameters, there were effects at subcellular and biochemical level, as shown by the biomarkers. Mixtures of pesticides, in some instances, affected earthworms differently from their single components, indicating interactions between the pesticides in mixtures, as shown by the measured endpoints. The NRR assay proved to be a good general biomarker of soil contamination, and the AChE activity could also be a valuable tool in assessing the effects of organophosphate mixtures and mixtures of organophosphates and pesticides from other groups. / AFRIKAANSE OPSOMMING: Nie-teiken organismes, soos erdwurms, word negatief beïnvloed deur mengsels van antropogeniese chemikalieë in landbou-omgewings. Die meeste studies wat handel oor die toksisiteit van chemiese mengsels het tot dusver gefokus op chemikalieë van dieselfde aard en met dieselfde meganismes van werking. Mengsels van chemiese stowwe kan egter as konglomerate van 'n verskeidenheid strukturele eienskappe en met verskillende toksiese meganismes in die omgewing aangetref word. Tydens die studie is gepoog om die effekte van enkel pestisiede sowel as mengsels daarvan op erdwurms te bestudeer, deur van lewensloop kenmerke (groei en voortplanting) en biomerkers (neutraalrooi retensietyd - NNR en inhibisie van asetielcholienesterase -AChE) as eindpunte gebruik te maak. 'n Verdere doel van die studie was om vas te stel of daar enige wisselwerkings tussen die verskillende pestisiede plaasvind, soos aangetoon deur die gemete eindpunte, en verder ook om die gebruik van die gekose biomerkers as maatstawwe van mengseltoksisiteit te evalueer. Die pestisiede wat gebruik is, is van drie verskillende groepe afkomstig: organofosfate, swaarmetale en piretroiede. Van hierdie drie groepe is vier van die pestisiede wat vry algemeen in boorde en wingerde in die Weskaap, Suid-Afrika, gebruik word, geïdentifiseer. Hierdie stowwe is chlorpyrifos (organofosfaat), azinphos-metiel (organofosfaat), koperoksichloried (swaarmetaalbevattende fungisied) en sipermetrien (piretroied). Erdwurms is in die laboratorium aan 'n reeks konsentrasies van chlorpyrifos en koperoksichloried as enkel toksikante en as 1:1 mengsels in kunsmatige grond, vir vier weke blootgestel. Voor en na die blootstellingsperiode is die biomassa van die wurms, as maatstaf van groei, bepaal en kokonproduksie, uitbroeisukses en getal nakomelinge per kokon bepaal as maatstawwe van voortplantingsvaardigheid. Groei (biomassaverandering) en voortplanting (kokonproduksie) is beinvloed deur behandeling met die hoogste konsentrasie (20 mg/kg) chlorpyrifos, terwyl geen effek van koperoksichloried of die mengsel van hierdie twee pestisiede gevind is nie. Daar is gevind dat beide die pestisiede, enkel en in die mengsel, die NRR tye beinvloed het. Die AChE aktiwiteit is beinvloed deur chlorpyrifos en die mengsel, maar nie deur die koperoksichloried nie. Korttermyn blootstellings van erdwurms (48 uur), in kunsmatige grondwater, van erdwurms aan chlorpyrifos, koperoksichloried, azinphos-metiel en sipermetrien as enkel toksikante en mengsels van chlorpyrifos-koperoksichloried, chlorpyrifos-azinphos-metiel en chlorpyrifos-sipermetrien, is gedoen en gevolg deur die bepaling van AChE inhibisie. Koperoksichloried, cypermetrien en die chlorpyrifos-sipermetrien mengsel het geen waarneembare effek op die AChE aktiwiteit gehad nie ?????. Die erdwurms wat blootgestel is aan die hoogste konsentrasie in die mengsel van chlorpyrifos-sipermetrien het doodgegaan. Die resultate het getoon dat die pestisiede nie in die korttermyn die lewensloopkenmerke in enige waarneembare mate geaffekteer het nie maar daar was effekte op sellulêre en biochemiese vlakke soos aangetoon deur die biomerkers. Sommige mengsels van die pestisiede het die erdwurms verskillend van die enkelstowwe geaffekteer. Daar het dus wisselwerking tussen sommige van die pestisiede wat in mengsels aangewend is, plaasgevind, soos aangetoon deur die gemete eindpunte. Die NRR toets, as breë-spektrum biomerker was 'n goeie maatstaf van kontaminasie in grond en daar is aanduidings dat die AChE aktiwiteit, as 'n spesifieke biomerker, 'n nuttige maatstaf kan wees om die effekte van organofosfaatmengsels en mengsels van hierdie chemiese groep en die van ander chemikalieë aan te toon.

Thesis (MSc)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Landfarming is a widely used method for the disposal of contaminants in the petrochemical industry. It involves ploughing the contaminants into the top soil layer allowing biological breakdown. A historically landfarmed site was identified at a South African petrol refinery. The refinery used to dispose so-called American Petroleum Institute (API) -sludge onto a landfarming site. API-sludge consisted of a mixture of oil and water soluble contaminants originating from a process of separating refinery waste from reusable water and oil. Landfarming on this site was discontinued after excessive quantities of sludge were ploughed into the soil over time and it became obvious that effective biodegradation could not take place. An environmental assessment had to be carried out to assess to what extent the soil has recovered from the contamination and after remediation was done over time. Bioassays together with chemical analyses were executed to determine the level of pollutants in the soil and to assess the integrated effects of their bioavailable fractions. The landfarming site of the refinery was divided into two sections namely, a more contaminated north-site and less contaminated south-site. Soil samples were collected from both sites as well as from an off-site (control site). The soils were analysed physically, chemically and used in the bioassays. Two additional control soils were also used, OECD-soil and LUFA2.2 soil. Chemical analysis of the site soils showed the presence of heavy metals and high levels of diesel range organic hydrocarbons. The north-site had higher levels of contaminants compared to the south-site. Three species of soil organisms were used in standardised tests: Eisenia andrei, Enchytraeus doerjesi and Folsomia candida were exposed to the respective soils to study their survival, growth, reproduction success and avoidance behavior. Exposures to both site-soils were not acutely toxic to any organisms. F. candida had a decrease in juvenile production in both north- and south-site soils (289.42 ± 58.62 and 253.33 ± 122.94 respectively) compared to the control soil (479.89 ± 30.42). E. doerjesi showed an increase in produced juveniles exposed to north- and south-site soil (339.75 ± 76.92 and 414.00 ± 17.78 ) compared to control soil (57 ± 34.39). E. andrei had similar cocoon production when exposed to south-site soil than in off-site soil (19.00 ± 5.3 and 18.5 ± 9.7 respectively) but significantly less in north-site soil (1.25 ± 0.7). Only E. doerjesi showed avoidance of north-site soil. To determine the sensitivity of the organisms to the API-sludge, they were exposed to concentration series of API-sludge-spiked control soils. The effect concentrations were calculated as the concentration of API-sludge that will decrease the studied endpoints by 50% of the control soil (EC50). The EC50s varied for each species exposed in the different control soils showing that the toxicity of the API-sludge is to a certain extent dependent on the physical soil properties of the substrate. The reproduction of F. candida were most sensitive to the API-sludge in off-site soil (EC50 = 90 mg/kg) and the E. doerjesi the least sensitive in LUFA2.2 soil (EC50 = 36000 mg/kg). Five plant species were exposed to API-sludge-spiked potting soil and the germination success, early growth rate and biomass were studied. The plants were not as sensitive to API-sludge as the soil animals. Lettuce and grass were affected the most by API-sludge and beans were the most resilient species. With the addition of low levels API-sludge to the substrate, the growth rate of beans was stimulated. This study showed that the south-site has been successfully remediated and most soil organisms exposed to these soils were not affected by the levels of toxicants present. However, exposures to north-site soil still had negative effects on soil organisms. It is recommended that hydrocarbon contamination should be further remediated in the north-site soil before landfarming should be allowed to continue. / AFRIKAANSE OPSOMMING: Ploegverwerking is ‘n algemene remediëringsmetode vir die verwerking van afvalmateriaal in petrochemiese industrieë. Dit behels die inploeg van toksiese afvalmateriaal in die boonstegrondlaag sodat dit biologies afgebreek kan word. ‘n Voorbeeld van ‘n histories ploegverwerkte grondstuk is geidentifiseer by ‘n Suid-Afrikaanse olieraffinadery. Die raffinadery het in die verlede van die grondstuk gebruik gemaak om sogenaamde Amerikaanse Petroleum Instituut-slik (API-slik) daarin te ploeg. Die API-slik bestaan uit ‘n mengsel van olie- en wateroplosbare kontaminante afkomstig van die proses waardeur die raffinadery se afvalprodukte van hernubare water en olie geskei word. Nadat oormatige konsentrasies slik in die grond ingewerk is en bioremediasie nie meer doeltreffend kon voortgaan nie, is die ploegverwerking gestaak. ‘n Omgewingimpakstudie moes uitgevoer word om te bepaal tot watter mate die grond herstel het nadat remediasie oor tyd uitgevoer is. Toksisiteitstoetse en chemiese analises is uitgevoer om die vlakke van besoedeling sowel as die biobeskikbare fraksie daarvan in die grond te bepaal. Die ploegverwerkte area van die raffinadery is in twee verdeel naamlik, ‘n meer gekontamineerde noordelike area en ‘n minder gekontamineerde suidelike area. Grondmonsters is van die onderskeie areas asook van ‘n ongekontamineerde veld (as kontrole) naby die ploegverwerkte area versamel Die gronde is fisies- en chemies geanaliseer en toksisiteitstoetse is uitgevoer. Twee addisionele kontolegronde is ook tydens die blootstellings gebruik naamlik, OECD- en LUFA2.2-grond. Die chemiese analises van die ploegverwerkte toetsgronde het getoon dat daar steeds swaarmetale en hoë vlakke van dieselgekoppelde organiese koolwaterstowwe in die gronde teenwoordig is. Kontaminante was in hoër konsentrasies teenwoordig in die grond van die noordelike gebied as in dié van die suidelike gebied. Drie spesies van grondorganismes is gebruik tydens standaard toksisitetitstoetse. Eisenia andrei, Enchytraeus doerjesi en Folsomia candida is blootgestel aan die onderskeie toets- en kontrolegronde waarna hul oorlewing, groei, voortplantingsukses en vermydingsreaksies bestudeer is. Blootstellings aan die ploegverwerkte toetsgronde het geen akute toksisiteit vir enige van die spesies getoon nie. F. candida se juveniele produksie was laer in beide noordelike- en suidelike toetsgronde (289.42 ± 58.62 en 253.33 ± 122.94 onderskeidelik) as in die kontolegrond (479.89 ± 30.42). E. doerjesi blootstellings het ‘n toename in juveniele getalle getoon in die noordelike- en suidelike toetsgronde (339.75 ± 76.92 en 414.00 ± 17.78) in vergelyking met die ongekontamineerde kontolegrond (57 ± 34.39). Kokonproduksie by E. andrei was soorgelyk in die suidelike toetsgrond en ongekontamineerde kontrolegronde (19.00 ± 5.3 en 18.5 ± 9.7 onderskeidelik) maar beduidend minder as in noordelike toetsgrond (1.25 ± 0.7). Slegs E. doerjesi het ‘n beduidende vermydingsreaksie vir die noordelike toetsgronde getoon. Om die sensitiwiteit van die organismes aan vars API-slik te bestudeer, is hulle blootgestel aan konsentrasiereekse van API-slik in die onderskeie kontrolegronde. Die effektiewe konsentrasie (EK50) is bereken as die konsentrasie van API-slik wat die bestudeerde eindpunte met 50% sal verminder in vergelyking met die kontrolegrond Die EK50-waardes vir al die spesies het verskil na blootstelling aan die onderskeie kontrolegronde. Dus, die toksisiteit van die API-slik is tot ‘n sekere mate ook afhanklik van die fisiese grondeienskappe van die blootsellingssubstraat. Die voortplanting van F. candida was die gevoeligste eindpunt vir die blootstelling aan API-slik in kontolegrond (EK50 = 90 mg/kg) en E. doerjesi was die minste gevoelig in LUFA2.2 grond (EK50 = 36000 mg/kg). Vyf plantspesies is ook blootgestel aan API-slikgekontamineerde potgrond en die saadontkiemingssukses, vroeë groeikoers en biomassa is bestudeer. Alhoewel plante nie so sensitief was vir die API-slik soos die gronddiere nie, was blaarslaai en gras die meeste geaffekteer tydens die blootstellings. Boontjies was die ongevoeligste en met die toevoeging van lae konsentrasies API-slik (2.5% API-slik), is hul groeikoers selfs gestimuleer. Uit die studie was dit duidelik dat die suidelike deel van die grondstuk meer suksesvol as die noordelike geremidieer is en dat meeste grondorganismes wat daaraan bloot gestel is nie geaffekteer is deur die vlakke van kontaminasie wat steeds teenwoordig is in die grond nie. Die toetsgronde uit die noordelike deel het egter steeds negatiewe effekte op die grondorganismes gehad. Dit word voorgestel dat die koolwaterstof kontaminasie verder geremidieër behoort te word in die noordelike deel van die grondstuk voordat verdere ploegverwerking van die afval daar gedoen word.

Thesis (MSc (Botany and Zoology))--Unkiversity of Stellenbosch, 2009. / Phylogeographic genetic structure has been documented for a number of southern African terrestrial taxa. Information regarding geographic population genetic structuring in multiple taxa, with differing life histories, can provide insights into abiotic processes such as vicariance. A fragment of the cytochrome b mitochondrial DNA gene of a plains-dwelling species, Otomys unisulcatus, was sequenced and analysed. Two closely related geographic assemblages were found. The first assemblage (lowland group) contains populations from both the eastern and western parts of the species range, and the second comprises populations from the Little Karoo (central group). The lowland group was shown to be in a state of population expansion after a relatively recent mitochondrial DNA (mtDNA) coalescence, while the genetic signature of the central assemblage was characterized by more genetic diversity indicative of an older lineage/genetic refuge. Areas of higher elevation (namely mountain ranges) appeared to be the main factor limiting gene flow between these two groups. Aridification cycles due to glacial maximum periods probably resulted in increased dispersal leading to the widespread distribution of common haplotypes throughout the lowland group. Morphological variation in skull shape and size has been shown to follow environmental clines in some rodents. Geometric morphometric analyses on the ventral and dorsal views of the craniums of O. unisulcatus were utilised to test whether the population groupings obtained in the genetic analyses would be recovered by morphometric analyses. In addition, it was also investigated which of the environmental factors investigated influenced skull shape and size. The genetic groupings were not recovered for either the cranial shape or size. Size variation in the females correlated positively with annual rainfall, and so by proxy with habitat productivity, indicating that females which inhabited areas with lower rainfall would be larger. The significant relationship between females’ centroid sizes and rainfall was thought to be as a result of the increased nutrient requirement by this gender in the production of offspring. The males did not show a significant correlation between any of the environmental variables and centroid size. There was a significant difference between the skull shapes of the genders, further verifying the sexual dimorphism in the species. Three major clusters were found (according to cranium shape) using a Two-Block Partial Least Squares Analysis (2B-PLS), which relate to the biome boundaries within the species’ range. Variations in shape were attributed to the varying needs for strong masticatory muscles resulting from differing diets. The skull shapes of specimens occurring along the escarpment were intermediate between the first two clusters. Cranial shape in the male dorsal view dataset was significantly correlated with the environmental variables block, possibly due to the much lower minimum temperature in the Sutherland population (a population which was not included in the female analyses). It was concluded that differing diets of individuals in the respective biomes influenced the shape of the cranium of both genders. The sexual dimorphism in the cranium shapes may be as a result of the females digging tunnels (using their teeth) underneath the stick nests. Otomys unisulcatus show high levels of phenotypic plasticity throughout the range and it thus appears that the species can adapt fast to the different environmental variables.