Thesis (PhD)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae) is a devastating pest of pome fruit in temperate regions of the world. Control of this pest, previously involved the extensive use of broad-spectrum insecticides. However, concerns over human safety, environmental impact, widespread dispersal of resistant populations of codling moth and the sustainability of synthetic pesticides in agroecosystems, has encouraged the development and use of alternative environmentally-friendly pest management technologies including the use of entomopathogenic nematodes. These nematodes are lethal pathogens of insects and belong to the families Steinernematidae and Heterorhabditidae, and are ideal candidates for incorporation into the integrated pest management programme currently being developed for residue-free pome fruit production in South Africa. The biological and ecological factors pertaining to the successful use of these nematodes for the control of codling moth were investigated in this study. Their use for bin-disinfestations was evaluated, focusing on the optimum handling conditions to ensure the survival and subsequent efficacy of the nematodes. The study proved that the local isolate SF41 of Heterorhabditis zealandica Poinar 1990 could be used for successful bin-disinfestation. The use of the same nematode isolate was also investigated for the disinfestation of mulch layers of diapausing codling moth larvae. An insect containment device which allowed for direct trial efficacy evaluation was identified and ecological factors pertaining to the successful use of nematodes for mulch disinfestation were investigated. The biological control potential of local nematode isolates, which had previously never been tested against codling moth larvae, was investigated in the laboratory under conditions as can be expected during orchard applications. The efficacy of the selected isolates was confirmed in field experiments. Innovative insect containment methods for above-ground trial efficacy evaluation in the field were investigated. Desiccation proved to be the most limiting factor to the survival and subsequent efficacy of the nematodes during field applications in temperate regions. The effect of low moisture levels on H. zealandica’s efficacy to control diapausing codling moth larvae was subsequently investigated and a starch-based formulation was further tested to overcome the issue of desiccation. Conclusive results indicated that there were several biological and ecological factors influencing the survival of nematodes and illustrated how these factors could be manipulated to overcome these issues and thereby ensure the efficacy of treatments. This is the first report of its kind to comprehensively investigate the use of South African entomopathogenic nematodes for the control of diapausing codling moth larvae and all results emanating from the study can be integrated into a framework for the commercial use of these nematodes in this regard in future. / AFRIKAANSE OPSOMMING: Kodlingmot, Cydia pomonella (L.) is ‘n ernstige sleutelplaag in appel- en peerboorde in gematigde klimaats gebiede wêreldwyd. In die verlede is hoofsaaklik breëspektrum insektedoders gebruik vir die beheer van hierdie plaaginsek. Maar, kommer oor veiligheid vir die mens, impak op die omgewing, verspreiding van weerstandbiedende populasies van kodlingmot en beperkte volhoubaarheid van sintetiese plaagdoders het die ontwikkeling en gebruik van alternatiewe plaagbeheer tegnologieë, insluitend die gebruik van entomopatogeniese nematodes, genoodsaak. Entomopatogeniese nematodese horende tot die families Steinernematidae en Heterorhabditidae, is ideale kandidate vir insluiting in die geïntegreerde plaagbestuur programme wat huidiglik ontwikkel word vir gebruik in plaaslike boorde met die uiteindelike doel om residu-vrye vrugte te produseer. In hierdie studie word die biologiese en ekologiese faktore bestudeer wat die sukses van ‘n nematode-toediening gemik op kodlingmot beïnvloed. Hierdie studie het bewys dat die lokale SF41 isolaat van Heterorhabditis zealandica Poinar 1990 gebruik kan word om vrugtekratte te disinfesteer van kodlingmot. Die gebruik van dieselfde isolaat vir die disinfestasie van deklae is ook ondersoek. ‘n Metode van insek-inkamping is ook ontwikkel wat die evaluering van toedienings vergemaklik en meer effektief maak. Die omgewings-toestande wat ook bydrae tot die oorlewing en gevolglike sukses van ‘n toediening is ook ondersoek. Die biologiese beheer potensiaal van ‘n paar lokale isolate wat nog nooit voorheen teen kodlingmot getoets is nie, is ook bestudeer. Die isolate se effektiwiteit is ook bevestig in veldproewe en insek-bekampings metodes wat meer van toepassing is vir bogrondse plaaginsekte is ook geïdentifiseer. Resultate dui daarop dat vogverlies en gevolglike uitdroging van nematodes die grootste beperkende faktor is vir hierdie tipe toedienings in gematigde gebiede en ‘n stysel-gebaseerde formulasie is dus ondersoek om hierdie probleem te oorkom. Die uiteindelike gevolgtrekking van die studie was, dat alhoewel daar verskeie biologiese en ekologiese faktore is wat die oorlewing van nematodes beperk, daar tog verskeie maniere is om hierdie faktore te manipuleer en sodoende te oorkom, wat bydrae tot die uiteindelike sukses van ‘n toediening. Hierdie is die eerste studie wat werklik die praktiese gebruik van lokale entomopatogeniese nematodes vir die beheer van kodlingmot ondersoek en alle bevindinge kan geïntegreer word in toekomende riglyne vir die kommeriële gebruik van nematodes vir die beheer van kodlingmot.

Thesis (PhD (Conservation Ecology and Entomology))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: There is a growing appreciation of the importance of non-timber forest products (NTFPs) and the role they play in the socio-economic wellbeing of rural communities and other stakeholders. Harvest systems to ensure sustainable harvesting are largely still lacking and overutilisation is of growing concern worldwide. In this study the science needed to underwrite management for sustainable use of NTFPs was explored. This was done using case studies of three different products harvested from natural forest in the southern Cape, South Africa viz. fern (Rumohra adiantiformis) fronds (leaves) as greenery in the florist industry, medicinal tree bark, and the corm (stem) of the geophyte Bulbine latifolia for medicinal use. The research approach enabled insight into the complexities of developing harvest systems for NTFPs, the input and expertise required to conduct applied research, and the variation in approach required for different products and plant growth forms. The study on R. adiantiformis showed that the adaptive management approach can be followed effectively with the development of harvest prescriptions for a species. Goalorientated, long-term monitoring, assessing harvest impact on the resource and natural fluctuations in population dynamics, are essential to verify that harvest prescriptions are sound and ecologically sustainable. However, if all relevant aspects are covered, the input required to develop and refine harvest systems through such monitoring may be extensive. Experimental stripping of medicinal tree bark showed that species respond differently to wounding, in terms of both bark regrowth and susceptibility to fungal and insect damage. The conceptual model and decision tree developed, demonstrated that tree response to wounding could be used effectively when choosing a management system for bark harvesting, and in informing prescriptions for strip harvesting. The proposed harvest system for the target species, as well as alternative options to meet the demand for bark can be successfully integrated with the existing multiple-use forest management system in the southern Cape. The study of the ecology and dynamics of B. latifolia showed that the species has a complex population dynamics and is abundant on the fynbos/forest ecotone, where it is associated with dry scrub forest communities. Although regeneration is sound, it has a slow rate of renewal in terms of corm diameter and length growth, limiting its harvest potential. The difference between ecotone and forest populations – in terms of population dynamics, plant demography and regeneration phenology – requires that consideration be given to differential harvest prescriptions for ecotone and forest populations. It was concluded that a simple generic process that provides for research to be focused on the relevant fields can be followed effectively with the development of harvest systems for NTFPs. However, sustainability also has a socio-economic and political dimension, further influenced by institutional arrangements. Considering the wide range of NTFPs used, socioeconomic circumstances and the dependence of rural communities on natural resources, a major challenge awaits forest managers in South Africa to develop harvest systems for sustainable use. Policy and decision makers need to appreciate the scientific skills and expertise, and financial resources required to realise this. / AFRIKAANSE OPSOMMING: Die belangrikheid van bosprodukte anders as hout en die rol wat dit in die sosio-ekonomiese welstand van landelike gemeenskappe en ander belanghebbendes kan speel, word toenemend besef. Oesstelsels om standhoudende benutting te verseker is grootliks afwesig en oorbenutting is wêreldwyd ’n toenemende bron van kommer. In hierdie studie word die wetenskaplike insette benodig om oesstelsels vir nie-houtbosprodukte te onderskryf, betrag. Dit is gedoen aan die hand van gevallestudies van drie bosprodukte wat uit natuurlike woud in die Suid-Kaap, Suid-Afrika, benut word, naamlik die blare van die varing Rumohra adiantiformis vir blommerangskikkings, medisinale boombas en die stam van die geofiet Bulbine latifolia vir medisinale doeleindes. Die navorsingsbenadering laat toe om insig te bekom in die kompleksiteit met die ontwikkeling van oesstelsels vir nie-houtbosprodukte, die insette en kundigheid benodig vir toegepaste navorsing, en die verskillende benaderings met verskillende bosprodukte en plantgroeivorms. Die studie oor R. adiantiformis dui aan dat ’n aanpasbare bestuursbenadering suksevol gevolg kan word met die ontwikkeling van oesvoorskrifte vir ’n spesie. Doelgerigte langtermynmonitering om die impak van inoesting op die bron en natuurlike fluktuasies in populasiedinamika te bepaal, is noodsaaklik om te kan aandui of oesvoorskrifte ekologiese standhoudendheid verseker. Die insette benodig om oesstelsels te ontwikkel en deur langtermynmonitering te verfyn, kan egter aansienlik wees. Eksperimentele basstroop dui aan dat boomspesies verskillend reageer op basverwydering in terme van bashergroei en vatbaarheid vir insek- en swamskade. ’n Konsepmodel en vloeidiagram vir besluitneming is ontwikkel en dui aan dat ’n boomspesie se reaksie op basverwydering effektief aangewend kan word in die keuse van ’n oesstelsel en die ontwikkeling van voorskrifte vir strookbenutting. Die voorgestelde oesstelsel vir die teikenspesies en ander alternatiewe om in die behoefte vir bas te voorsien, kan doeltreffend geintegreer word met die bestaande meervoudige-benutting woudbestuurstelsel in plek in die Suid-Kaap. Die studie oor die ekologie en dinamika van B. latifolia dui aan dat die soort goed verteenwoordig is in die fynbos/woud-ekotoon, dat dit geassosieer is met droë struikwoud, en ’n komplekse populasiedinamika het. Alhoewel dit goed verjong, het dit, gemeet aan stamdeursnee- en -lengtegroei, ’n lae groeitempo wat die benuttingspotensiaal van die spesie beperk. Die verskille tussen ekotoon- en woudpopulasies – in terme van populasiedinamika, demografie en reproduksiefenologie – vereis dat oorweging geskenk word aan verskillende oesvoorskrifte vir ekotoon- en woudpopulasies. ’n Eenvoudige, generiese proses wat verseker dat navorsing gefokus is op die toespaslike velde kan suksesvol gevolg word met die ontwikkeling van oesstelsels vir niehoutbosprodukte. Standhoudendheid het egter ook ’n sosio-ekonomiese en politieke komponent wat verder beinvloed word deur institusionele strukture. Inaggenome die wye verskeidenheid van nie-houtbosprodukte wat benut word, sosio-ekonomiese omstandighede en die afhanklikheid van landelike gemeenskappe van natuurlike hulpbronne, is die ontwikkeling van oesstelsels vir standhoudende benutting ’n groot uitdaging vir woudbestuursinstansies. Beleidmakers en besluitnemers moet ’n waardering ontwikkel vir die wetenskaplike kundigheid en kennis, en finansiële hulpbronne, wat benodig word om dit te bewerkstellig.

Thesis (PhD (Conservation Ecology and Entomology))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: Natural and semi-natural ecosystems and human communities worldwide are under siege from a growing number of destructive invasive alien species. Alien species are those whose presence in an area is due to intentional or accidental introduction as a result of human activities. Some alien species become invasive, and some cause tremendous destruction to the ecosystem and their stability, but we do not yet understand fully the many factors that determine the levels of invasiveness in alien species. However, management of alien plants requires a detailed understanding of the factors that make them invasive in their new habitat. The aim of this study was to explore in detail the processes and potential for invasion of Schinus molle (Peruvian pepper tree) into semiarid savanna in South Africa and to examine the potential for this species to invade further in these ecosystems, and in other South African biomes. In this thesis I explored the patterns and processes of invasion of S. molle in semiarid savanna using small-scale experiments to investigate physical and ecological barriers to invasion that prevent or accelerate the invasion of this species. I examined factors such as pollination; seed production; seed dispersal; seed predation and viability, all known to contribute to invasiveness. I highlighted the critical role of microsite conditions (temperature, humidity, water availability) in facilitating S. molle seedling establishment in semi-arid savanna and demonstrated that microsite type characteristics need to be considered for management and monitoring of the species in South Africa. I demonstrated the ability of S. molle to out-compete indigenous woody plants for light and other resources and also showed that disturbance of natural ecosystems was not a prerequisite for invasion, although human activities such as tree planting have played a major role in disseminating this species in South Africa. Predicting the future distribution of invasive species is very important for the management and conservation of natural ecosystems, and for the development of policy. For this reason, I also assessed the present and potential future spatial distribution of S. molle in South Africa by using bioclimatic models and a simulation-based spread model. I produced accurate profiles of environmental conditions (both biophysical and those related to human activities) that characterize the planted and naturalized ranges of this species in South Africa, by linking species determinants, potential habitat suitability and likely spread dynamics under different scenarios of management and climate change. All those components provided insights on the dynamics of invasions by fleshy-fruited woody alien plants in general, and on S. molle invasions in South Africa in particular. I developed a conceptual model that described S. molle population dynamics leading to an understanding of the processes leading to the invasive spread of this species in South Africa. This work also emphasized the need for policy review concerning the invasive status of S. molle in South Africa, and recommendations are made for future research. / AFRIKAANSE OPSOMMING: Die natuurlike and half-natuurlike ekosisteme sowel as menslike gemeenskappe wereldwyd word bedreig deur ‘n groeiende hoeveelheid indringerplantspesies. Indringerplantspesies (daardie spesies wie se teenwoordigheid toegeskryf kan word aan opsetlike of toevallige inbringing deur menslike toedoen) is ‘n bedreiging nie net vanweë die massiewe verwoesting van die ekosisteme en ekosisteemstabilitiet nie, maar ook omdat ons nog nie ten volle verstaan hoe hulle van skaars in hul natuurlike omgewing tot dominant in hul nuwe habitat gaan nie. Bestuur van indringer plante vereis ’n begrip van biologise en ekologiese faktore wat lei tot hulle indringing in die nuwe habitat. Die primêre doel van hierdie studie was om in detail uit te vind wat die prosessesse en potensiaal is vir die indringing van S. molle (die Peruviaanse peper boom) in droë savanna en om indringingspatrone in droë savanna met huidige en potensieële toekomstige patrone in ander Suid-Afrikaanse biome te vergelyk. In hierdie tesis ondersoek ek die patrone en prosesse wat verband hou met die indringing van S. molle in droë savanna deur gebruik te maak van kleinskaalse eksperimente om fisiese en ekologise hindenisse te ondersoek wat indringing van S. molle in Suid-Afrika voorkom of versnel. Dit sluit faktore in wat bekend is om by te dra tot indringing van plant spesies, soos bestuiwing, saadproduksie, saadpredasie en kiemkragtigheid. Ek het die kritieke rol beklemtoon van mikroomgewingskondisies (temperatuur, humiditeit, waterbeskikbaarheid) in die fasilitering van S. molle saailingvestiging in droë savanna en het gedemonstreer dat die tipe mikroomgewingskarakteristieke in ag geneem moet word by betuur en monitering van die verspreiding van S. molle in Suid-Afrika. Ek het die vermoë van S. molle om inheemse plante te uitkompeteer gedemonstreer, en het gewys dat versteuring van natuurlike ekosisteme nie ’n voorvereiste vir S. molle indringing was nie, hoewel menslike aktiwiteite soos boomaanplantings ’n groot rol speel deur by te dra tot indringing van hierdie spesie in Suid-Afrika. Voorspelling van toekomstige verspreiding van indringerspesies is baie belangrik vir die bestuur en bewaring van natuurlike ekosisteme, sowel as vir ontwikkeling van wetgewing. Daarom is die huidige en potensiele toekomstige ruimtelike verspreiding van S. molle in Suid-Afrika bereken deur inkorporering van bioklimaatsmodelle en simulering gebasseer op ’n verspreidingsmodel. Ek het derhalwe akkurate profiele van omgewingstoestande (beide fisiese en daardie wat verband hou met menslike aktiwiteite) wat die aangeplante en natuurlike omvang van die spesie in Suid-Afrika kenmerk geproduseer deur spesiedeterminante, potensieële geskiktheid van habitatte en moontlike verspeidingsdinamika onder verskillende bestuursscenarios en kimaatsverandering te koppel. Al hierdie komponente verskaf insig in die dinamika van die indringing van houtagtige plante met vlesige vrugte oor die algemeen en S. molle in besonder in Suid- Afrika. Hierdie werk beklemtoon ook die behoefte vir hersiening van beleidsrigtings wat betrekking het op die indringerstatus van S. molle in Suid-Afrika en maak aanbevelings vir toekomstige navorsing.

Thesis (PhD)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Humanity‘s growing separation from nature is central to the convergent social and ecological crises facing earth. This is both a psychological (e.g. perceptual, emotional) and physical (e.g. experiential) disconnect and is therefore better understood as a crisis in consciousness. This research arises out of an intense interest in how to alleviate humanity‘s fading connectedness with nature and, specifically, if meaningful nature experience is capable of healing the divisive ways in which humans tend to think, see and act in the world. This study brings together four core themes: connectedness with nature (CWN), invasive alien species (IAS), and education for sustainability (EfS); each of which are explored around - and in relationship to - the core concept of meaningful nature experience (MNE).1 In doing so, this transdisciplinary research utilizes a theory of complexity to integrate diverse disciplinary perspectives by drawing upon: (conservation) ecology; (environmental-/eco-) psychology; (sustainability) education; and phenomenology as a guiding philosophy. Adopting an interpretivist and pragmatic approach, this research employs mixed methods (quantitative and qualitative/phenomenological analysis) to, firstly, uncover the essences which help describe what MNE feels like (how it appears in consciousness) and that which makes MNE what it is. Secondly, the study explores the relationship between MNE and CWN; the extent to which MNE is perceived to influence attitudes and environmentally responsible behaviour (ERB); and whether ecological change as experienced through IAS may affect MNE or, in turn, how MNE and CWN influence perceptions on IAS. Thirdly, the research examines the implications of the above for EfS: is there merit for integrating MNE and CWN in EfS? What would such a process look like and how can it be applied in a way which revitalizes EfS? Finally, as a form of heuristic inquiry, this study represents my process of conscious transformative learning. Reflective narratives are dispersed throughout this dissertation to capture this enriching personal journey. Research findings draw on over 200 unique accounts of MNEs which were elicited from: online and public questionnaires; in-depth interviews, email submissions and complemented by in-situ field observation and participation. The questionnaires and in-depth interviews also elicited responses on CWN, IAS and EfS. The research finds that a MNE is triggered by an unexpected encounter with the 'non-ordinary‘ in nature. It is characterized by heightened sensory awareness (e.g. the beauty and detail of natural phenomena arrest our attention), intensified emotional (e.g. awe, amazement) and physiological responses (e.g. a 'rush‘). If an animal is involved, close proximity, extended length of time and reciprocity are key themes. For a MNE not involving an animal, perceived aliveness, vibrancy and energy pervading the land-/ sea-/ sky-scape is primary. As mind meets matter, one feels interrelatedness and a diminished sense of self. The privilege to commune with an 'other‘ (re)defines a person‘s being and belonging in the world. Synchronicity as a MNE is distinctive as an uncanny (e.g. numinous) experience of: insight; flow; guidance; a 'knowing‘; and interconnectedness. Respondents who have had a MNE exhibit a higher CWN; a positive correlation exists between frequency of MNE (fMNE) and CWN. Stronger correlations with CWN were found when a wild animal was involved in the MNE. Spiritual / religious practices positively correlate with fMNE and CWN with regular displays of gratitude toward nature returning slightly stronger correlations with CWN. Strongest correlations were found between the experience of synchronicity and CWN. A qualitative analysis of respondents‘ MNEs and their responses on how they perceive their MNE(s) to have changed them, found multiple and diverse mention of (newfound) appreciations of (inter)connectedness. This suggests that MNE acts as a conduit for CWN: one powerful MNE may be sufficient to catalyse the process; however, a higher fMNE increases the likelihood for heightened CWN. Such results affirm the idea that MNEs facilitate a relational worldview necessary for a consciousness attuned to CWN. CWN is considered to be a reliable predictor for ERB. Over 90% agreement was found between respondents on the positive impact of MNEs in: shaping their views on nature and biodiversity; influencing their current behaviour and actions toward nature and the environment; and heavily influencing, changing or transforming their outlooks on life. The most common themes to emerge on how MNE was perceived to have changed respondents related to understanding of (inter)connectedness/interdependence; career choice; respect for nature / life; and new ways of seeing the world. This supports the premise that, by affectively bonding with nature, MNEs can motivate: ERB; life paths into conservation-minded careers; and serve as catalysts for personal growth and transformation, particularly when complemented with reflection, social (guided) facilitation and ecological literacy. The presence of IAS in landscape is likely to adversely affect MNE for stated reasons of ecological impacts, diminished 'naturalness‘, destructiveness and reduced diversity. Those viewing IAS as potentially enhancing their MNEs cite reasons of beauty, novelty and enjoyment. Respondents‘ CWN does not appear to affect perceptions of IAS; however, elevated CWN may invoke empathy, a sense of relatedness and appreciation of their intrinsic value as 'life‘. IAS may also feature in MNEs and, through experiential and metaphorical insight, can deliver newfound understandings of social and ecological connections as they relate to IAS. Respondents concur that today‘s education does not prepare society to learn from MNE: overwhelming agreement was found on the societal and ecological benefits of an education that promotes understanding of MNE through a blend of intellectual concepts; experiential activities; values and ethics; and integrated learning approaches. Experiential nature-based activities were encouraged as vital EfS vehicles for enhancing sensory awareness; respect for nature; ecological knowledge and encountering connectedness. In-depth interviewees saw future EfS opportunities and solutions as focusing more on: participating with nature; bridging spirituality and science; facilitating 'openness‘ and shared experience; instilling values reflecting an interconnected reality; mentoring; contemporary rites of passage; and simply learning to live better. The essence of this research is an expanded appreciation of connectedness - embodying Nature, Community, Self, Source - and the manifold ways it is encountered through MNE. Revitalized EfS (realized through Theory edU) invites a consciousness that attends to an enlivening process of connecting, harmonizing and becoming. / AFRIKAANSE OPSOMMING: Hierdie studie bring vier kern temas na vore: verbintenis met die natuur (VMN), indringende uitheemse spesies (IUS), en opvoeding vir volhoubaarheid (OVV); waarvan elk verken is rondom – en in verhouding is tot die kern konsep van betekenisvolle natuur ervaring 2 (BNE). Deur dit te doen, wend hierdie transdisiplinêre studie 'n teorie van kompleksiteit aan om diverse dissiplinêre perspektiewe te integreer deur gebruik te maak van: bewarings ekologie; omgewings-/eko- sielkunde; onderwys; en femenologie as 'n rigtinggewende filosofie. Deur 'n interpretatiewe en pragmatiese benadering aan te neem, is gemengde metodes (kwantitatief en kwalitatief / femenologiese analise) gebruik om eerstens die essensies wat help om te beskryf hoe BNE voel (hoe dit in die bewussyn voorkom) en dit wat BNE maak wat dit is, te ontbloot. Tweedens verken die studie die verhouding tussen BNE en VMN; die mate waartoe BNE beskou word om houdings en omgewings verantwoordelike gedragte beïnvloed (OVG); en of ekologiese verandering soos deur IUS ervaar word BNE kan affekteer, of, op sy beurt, hoe BNE en VMN persepsies van IUS kan beïnvloed. Derdens bestudeer die navorsing implikasies van die bogenoemde vir OVV: is daar meriete vir die integrasie van BNE en VMN in OVV? Hoe sal so 'n proses lyk en hoe kan dit toegepas word op 'n manier wat OVV weer nuwe lewe sal gee? Ten einde, as 'n vorm van heuristiese ondersoek, stel hierdie studie my proses van bewuste transformatiewe leer voor. Reflektiewe narratiewe is regdeur die proefskrif versprei om hierdie verrykende persoonlike reis vas te lê. Navorsing bevindinge gebruik meer as 200 unieke verklarings van BNE‘s wat aan die lig gebring is deur: aanlyn en publieke vraelyste; in-diepte onderhoude, e-pos indienings en dit is gekomplementeer deur in-situ veld observasie en deelname. Die vraelyste en in-diepte onderhoude het ook reaksies op VMN, IUS en OVV ontlok. Die navorsing het bevind dat 'n BNE word veroorsaak deur 'n onverwagste ontmoeting met die 'nie-gewone‘ in die natuur. Dit word gekarakteriseer deur verhoogde sensoriese bewustheid (bv. die prag en besonderhede van natuurlike verskynsels beset ons aandag), versterkde emosionele (bv. verwondering en verbasing) en psigologiese reaksies (bv. 'n stormloop). Indien 'n dier betrokke is, is nabyheid, verlengde duur van tyd en wederkerigheid sleutel temas. Vir 'n BNE wat nie 'n dier insluit nie, is waarneembare lewendigheid, dinamiek en energie wat die landskap / see / luglandskap deurdring primêr. Soos wat die gees die stof ontmoet, voel 'n mens 'n onderlinge verband en 'n verminderde sin van die self. Die voorreg om in noue aanraking met 'n 'ander‘ te kan wees (her)definieër 'n persoon se wese en behoort in die wêreld. 'Synchronicity‘ as 'n BNE is kenmerkend as 'n ongelooflike (bv. numineuse) ervaring van: insig, vloei, leiding; 'n 'wete‘; en onderlinge verbintenis. Respondente wat 'n BNE gehad het, het 'n hoër VMN getoon; 'n positiewe korrelasie bestaan tussen die frekwensie van BNE (fBNE) en VMN. Sterker korrelasies met VMN was gevind in die geval waar 'n wilde dier in die BNE betrokke was. Geestelike / religieuse praktyke korreleer positief met fBNE en VMN waar gewone openbarings van dankbaarheid tot die natuur effens sterker korrelasies met VMN terugbring. Die sterkste korrelasies was gevind tussen die ervaring van 'synchronicity‘ en VMN. 'n Kwalitatiewe analise van respondente se BNE‘s en hul response van hoe hulle hul BNE(s) as dit wat hul verander het, beskou, het veelvoudige en diverse antwoorde van (nuutgevonde) erkennings van (onderlinge) verbintenis navore gebring. Dit dui daarop dat BNE as 'n toevoerbuis vir VMN optree: een kragtige BNE mag voldoende wees om die proses te kataliseer; aan die anderkant verhoog 'n hoër fBNE die waarskynlikheid vir verhoogde VMN. Sulke resultate bevestig die idee dat BNEs 'n relasionele wêreldbeskouing is wat nodig is vir 'n bewustheid wat ingestel is vir VMN. VMN word as 'n betroubare voorspelling vir OVG beskou. Meer as 90% van respondente was in ooreenstemming ten opsigte van die positiewe impak van BNEs in: die vorming van hul beskouings van die natuur, biodiversiteit; beïnvloeding van hul huidige gedrag en aksies tot die natuur en die omgewing; en hoe dit hul vooruitsigte op die lewe hewig beïnvloed, verander of transformeer. Die meesal gemene temas wat ontluik het, was oor die beskouing van hoe BNE respondente se verstaan aangaande (onderlinge)verbintenis / onafhanklikheid; beroepskeuse; respek vir die natuur / lewe; en nuwe maniere om na die wêreld te kyk, verander het. Dit ondersteun die uitgangspunt, dat deur affektiewelik met die natuur in verbinding te tree, BNEs gemotiveer kan word: OVG; lewens paaie tot bewaring-gesinde beroepe; en as katalisators dien vir persoonlike groei en transformasie, veral as dit met refleksie, sosiale (begeleide) fassilitering en ekologiese geletterdheid gekomplimenteer word. Die teenwoordigheid van IUS in 'n landskap kan waarskynlik BNE nadelig affekteer weens verklaarbare redes van ekologiese impakte, afneembare 'natuurlikheid', verwoestendheid en verminderde diversiteit. Diegene wat IUS as iets positief tot hul ervaring beskou, verskaf redes soos skoonheid, nuutheid en genot. Dit wil voorkom of deelnemers se VMN nie algemene persepsies van IUS affekteer nie; alhoewel, verhoogde VMN empatie, verwantskap en waardering vir hul intrinsieke waarde as 'lewe' mag oproep. IUS mag ook in BNE vertoon en deur ervarings- en metaforiese insig, kan dit waardevolle nuut-bevinde begrippe van sosiale en ekologiese verbande soos wat hulle aansluit by die probleem van IUS, lewer. Respondente is dit eens dat vandag se onderwys nie die samelewing voorberei om te leer van BNE nie: oorweldigende ooreenstemming was gevind aangaande die maatskaplike en ekologiese voordele van onderwys wat die verstaan van BNE bevorder deur middel van 'n vermenging van intellektuele konsepte; ervarings leeraktiwiteite; waardes en etiek; en geïntegreerde leer benaderings. Ervarings leer natuur-gebaseerde aktiwiteite was aangemoedig as essensiële middels vir OVV vir die verhoging van sensoriese bewussyn; respek vir die natuur, ekologiese kennis en die teëkoming van verbintenis. In-diepte ondervraagdes het geleenthede en oplossings vir toekomstige OVV gesien in terme van 'n groter fokus op: deelname aan die natuur; die orbruging van spiritualiteit en wetenskap; fassilitering van 'oopheid‘ en gedeelde ervaring; vestiging van waardes wat 'n onderlinge verbonde realiteit reflekteer; mentorskap; kontemporêre deurgangsrites; en om eenvoudig te leer om beter te lewe. Die kern van hierdie navorsing behels 'n toenemende waardering van verbintenis – beliggaming van die Natuur, Gemeenskap, Self, Bron – en die menigvuldige maniere waar op dit deur BNE ondervind is. Hernude OVV (soos ontdek deur Theory edU) nooi 'n bewustheid uit wat aandag skenk aan 'n verlewendige proses van verbintenis, harmonisering en wording.

Thesis (PhD)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: As the world’s human population increases, more pressure is placed on the management of natural resources. In response, we need an efficient means of monitoring, not only the quantity of these resources but also their quality. No comprehensive standard metric has been developed to assess environmental quality of a biotope, or to define the nature and extent of environmental degradation at this spatial scale. Currently in conservation management, various landscapes are being evaluated for spatial heterogeneity, by making use of species surrogates such as species richness, relative abundance, diversity indices and phylogenetic indices, as well as environmental surrogates. These values are then used towards conservation, where those systems with high intrinsic heterogeneity are usually considered more important than those with low heterogeneity at least when given the choice between the two. Yet, the actual quality of the biotopes within the landscapes is rarely taken into consideration. This study therefore develops and tests a Biotope Quality Index (BQI) to study this point in depth. The BQI makes use of arthropod assemblages as bioindicators of the level of disturbance within a biotope. Firstly, I summarize the literature on the concept of environmental health, and define it as “An ecosystem is healthy, if it can sustain an optimal number of species with optimal population sizes and their ecological processes, thus providing and optimal heterogeneous sustainable system with sufficient resources, and indicated adequate resistance when under perturbational stress, but still allowing natural succession to take place” Against this background, I then review the use of certain Arthropoda as bioindicators, as arthropods are small, mobile, environmentally sensitive, easily sampled, and readily available. These features together make arthropods good subjects for testing the BQI. I then compare the BQI with diversity indices currently used as surrogates of biotope quality. The outcome was that the BQI stood out as a significantly better indicator than the currently available indices for assessing environmental quality of a biotope. Furthermore, during the selection process, I also tested the use of guilds for BQI evaluation, and found that the scavenger (represented by Formicidae) and decomposer (represented by Collembola) guilds were the most significant. The effect of seasonality was also tested. I found the best results with the BQI were when data are pooled from all seasons of the year. A case study, making use of the BQI evaluation, was conducted at a site in the Cape Floristic Region, South Africa (Jonkershoek Valley). BQI results suggested that the agricultural management and tourism within the locality might have an effect on biotope quality. This study has shown that use of the BQI is a useful and practical management tool for evaluating environmental quality of a biotope towards conservation management. / AFRIKAANSE OPSOMMING: Met die vermeerdering van mense op die Aarde, wat meer druk plaas op ons natuurlike hulpbronne en omgewing is daar ‘n aanvraag na doeltrefende maniere wat nie net die kwantiteit maar ook die kwaliteit van die hulbron evalueer. Geen betroubare standard bestaan om biologiese kondisies of die kwaliteit van n omgewing te meet nie. Heidiglik maak wetenskaplikes staat op die bepaling van diversiteit en ander voogde soos spesies rykheid en diversiteit indeksies as voog vir kwaliteit. Die waardes word dan gebruik binne die omgewings bestuur praktyke en bevooroordeel omgewings met ‘n hoë diversiteit, terwyl die kwaliteit van omgewing skaarslik na gekyk word. Hiervolgens, onwikkel ons n Omgewings Kwaliteit Indeks (OKI), wat gebruik maak van Arthropoda saamestellings as bioindikator van die vlak van verval binne ‘n omgewing. Verder sluit die tesis n literatuur studie van die omgesings gesondheid teorie, en die gebruik van arthropoda as bioindikators. As basis van die studie, definieër ons ‘n gesonde omgewings as ‘n omgewing wat’ n optimal hoeveelheid spesies en hulle ekologiese prosesse kan handhaf, en daarom verwys na ‘n diverse onderhoubare sisteem met genoegsame hulpbronne en kan genoegsame weerstand bied onder omgesings stres, maar gee geleentheid vir naturlike suksesie om plaas te vind Ons het verder die OKI getoets teen ander diversiteit’s indeksies, waar ons gevind het dat die OKI evaluering ‘n statistiese beklemtonde verskil toon as bioindikator van omgewings kwaliteit. Verder het ons voorkeer getoets, in gedrags groupe en gevind dat die versamellaars groep (verteeenwoordig deur Formicidae) en die afbrekers groep (verteenwoordig deur Collembola) die beste resultate toon. Seisoene het ook ‘n uitwerking en ons het gevind die groupeering van data ingesamel oor alle seisoene die beste resultate getoon. ‘n Ondersoek studie wat gebruik maak van die OKI evalueering, was gekondakteer in die Jonkershoek valei en het getoon dat die landbou plaagbestuur en toerusme ‘n negatiewe effek het op die omgewing. Verder het die OKI evalueering getoon dat aanplanting van Denne plantasies die kwaliteit van ‘n omgewing verlaag. Die studie het verder getoon dat die OKI evalueering ‘n betroubare evalueerings metode is vir die bestuur van ‘n omgewings, terwyl die diversiteits indeksies nie geskik is as bioindikator van omgewings kwaliteit nie.

Thesis (PhD)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Soft, serene insect songs add an intrinsic aesthetic value to the landscape. Yet these songs also have an important biological relevance. Acoustic signals across the landscape carry a multitude of localized information allowing organisms to communicate invisibly within their environment. Ensifera are cryptic participants of nocturnal soundscapes, contributing to ambient acoustics through their diverse range of proclamation songs. Although not without inherent risks and constraints, the single most important function of signalling is sexual advertising and pair formation. In order for acoustic communication to be effective, signals must maintain their encoded information so as to lead to positive phonotaxis in the receiver towards the emitter. In any given environment, communication is constrained by various local abiotic and biotic factors, resulting in Ensifera utilizing acoustic niches, shifting species songs spectrally, spatially and temporally for their optimal propagation in the environment. Besides the importance of Ensifera songs from an ethological point of view, the multitude of species-specific signals provide an acoustic tapestry representing species diversity across ecological gradients and over time. Acoustic inventorying and monitoring of the landscape can reflect the environmental status of ecological systems, from natural to disturbed by human influence. In contrast to traditional survey techniques, sound recording and interpretation is a non-invasive method that allows for the detection and classification of highly cryptic, yet insightful indicators of ecosystem change. Here, acoustic monitoring was used across diverse ecological gradients to improve understanding of species diversity patterns, and how they change in response to both natural gradients and in response to the human dominated landscape mosaic. This study was undertaken in three geographic locations from tropical rain forest of Brunei, Borneo, to the landscapemosaic of plantation forestry in KwaZulu-Natal, South Africa, and to the botanically rich, mountain fynbos region of the Cape Floristic Region, also in South Africa. Each region provided a diverse and particular landscape to test the value of acoustic surveys for determining local diversity patterns across natural gradients and to assess the value of the technique for assessing the impact human influence across landscapes. In tropical rainforests, an entire acoustic guild was investigated to determine how acoustic species partition their acoustic communication channels spectrally, temporally and spatially, to avoid acoustic interference. The overall assemblage showed considerable spectral partitioning. Diurnally active species showed low temporal niche overlap, whereas nocturnal species did not utilize temporal partitioning. Lack of nocturnal temporal partitioning suggests other mechanisms of acoustic avoidance are sufficient to avoid acoustic overlap, or that there are insufficient cues to partition nocturnal acoustic environments. Acoustic species also utilized spatial partitioning, with distinct acoustic assemblages at vertical heights and with elevation. Utilization of a range of different strategies allow many species to communicate with conspecifics with little or no interference from other species in a signal rich environment. Acoustic profiling was also undertaken in KwaZulu-Natal, South Africa, across a plantation forestry landscape mosaic with diverse ecological gradients containing both alien and indigenous vegetation, as well as boarding large natural protected areas. Areas covered in alien timber or non-endemic grass were devoid of acoustic signals. Managed areas that were mowed and heavily grazed were not effective in maintaining the natural complement of nocturnal acoustic species. Within natural vegetation patches inside plantations, acoustic species richness increased with plant heterogeneity and patch size. Patches of indigenous vegetation within the plantation matrix effectively reduced the contrast of transformed landscapes with surrounding natural areas, with indigenous forest patches containing a highly characteristic acoustic species assemblage. Within the botanically rich, mountain fynbos region of the Cape Floristic Region, acoustic profiling was conducted across gradients of elevation, season and vegetation. Across these gradients, katydid acoustic signals were identified and characterized for the first time. This resulted in the discovery of two new katydid species and a novel sound producing structure in a carabid beetle, a species previously unknown to produce sound. Acoustic diversity across seasonal and elevational gradients increased with increasing temperatures. Climatic variability along the elevational gradient produced variation in seasonal phenology. Katydids also utilized high frequency acoustic signals, which is probably an adaptation to overcome background noise from wind, so prevalent in this area. Furthermore, despite producing conspicuous signals for mate attraction and pair formation, katydids were found not to be part of bat-eared fox diet, an insectivorous, nocturnal predator that uses its characteristic large ears to detect sounds made by invertebrate prey. This study shows the value of using acoustic emissions from katydids to identify acoustic diversity patterns across ecological gradients and in response to human impacts on the landscape. / AFRIKAANSE OPSOMMING: Sagte, rustige insekliedjies voeg ‘n intrinsieke estetiese waarde aan die landskap. Tog is hierdie liedjies ook van belangrike biologiese waarde. Akoestiese seine oor die landskap dra ‘n magdom plaaslike inligting wat organismes in staat stel om onsigbaar te kommunikeer binne hul omgewing. Langhoringsprinkane is kriptiese deelnemers van die nagtelike klankomgewing en dra by tot die omringende akoestiek deur hul verskeidenheid van proklamasieliedjies. Alhoewel dit nie sonder inherente risiko’s en beperkings is nie, is die belangrikste funksie van seine seksuele advertering en paarvorming. Vir akoestiese kommunikasie om effektief te wees, moet seine hul geënkodeerde inligting handhaaf, sodat dit sal lei tot positiewe fonotaksis in die ontvanger teenoor die emittor. In enige gegewe omgewing, word kommunikasie beperk deur verskeie plaaslike abiotiese en biotiese faktore. Dit lei tot die gebruik van akoestiese nisse deur langhoringsprinkane, wat hulle liedjies spektraal, ruimtelik en temporeel aanpas vir optimale verspreiding in die omgewing. Benewens die belang van die langhoringsprinkaan liedjies uit ʼn etologiese oogpunt, bied die menigte spesie-spesifieke seine ʼn akoestiese tapisserie wat spesiesdiversiteit verteenwoordig oor ekologiese gradiënte en oor tyd. Akoestiese opname en monitering van die landskap kan die omgewingstoestand van ekologiese stelsels weerspieël, van natuurlike tot menslik versteurde stelsels. In teenstelling met tradisionele opnametegnieke, is klankopname en interpretasie ʼn nie-indringende metode wat dit moontlik maak om hoogs kriptiese, nog insiggewende indikators van ekosisteemverandering op te spoor en te klassifiseer. In hierdie studie is akoestiese monitering gebruik oor diverse ekologiese gradiënte om ons begrip te verbeter van spesies diversiteitspatrone, en hoe dit verander in reaksie op beide natuurlike gradiënte en in reaksie op die menslik gedomineerde landskapmosaïek. Hierdie studie is onderneem in drie geografiese liggings: tropiese reënwoud in Brunei, Borneo, die landskapmosaïek van plantasiebosbou in KwaZulu-Natal, Suid-Afrika, en die plantryke, bergfynbos-streek van die Kaap Floristiese Streek, ook in Suid-Afrika. Elke streek het 'n diverse en besondere landskap verskaf om die waarde van akoestiese opnames te toets vir die bepaling van plaaslike diversiteitspatrone in natuurlike gradiënte, asook om die waarde van die tegniek te bepaal vir die beoordeling van die impak van menslike invloed oor landskappe. In tropiese reënwoude, is 'n hele akoestiese gilde ondersoek om te bepaal hoe akoestiese spesies hul akoestiese kommunikasiekanale spektraal, ruimtelik en temporeel verdeel om akoestiese inmenging te vermy. Die algehele groep het aansienlike spektrale verdeling getoon. Dagaktiewe spesies het lae temporele nisoorvleueling getoon, terwyl nagtelike spesie nie temporele verdeling benut het nie. Gebrek aan nagtelike temporele verdeling dui daarop dat ander meganismes van akoestiese vermyding voldoende is om akoestiese oorvleueling te vermy, of dat daar onvoldoende seine is om nagtelike akoestiese omgewings te verdeel. Akoestiese spesies het ook ruimtelike verdeling benut, met verskillende akoestiese spesiesversamelings op vertikale hoogtes en met hoogte bo seevlak. Die gebruik van 'n verskeidenheid van strategieë maak dit moontlik vir spesies om te kommunikeer met min of geen inmenging van ander spesies in 'n seinryke omgewing. Akoestiese profielsamestelling is ook onderneem in KwaZulu-Natal, Suid-Afrika, oor 'n plantasiebosbou landskapmosaïek met diverse ekologiese gradiënte wat beide uitheemse en inheemse plantegroei, sowel as groot, natuurlike, beskermde gebiede ingesluit het. Gebiede wat bestaan het uit uitheemse timmerhoutbome of nie-endemiese gras, was heeltemal sonder akoestiese seine. Bestuursgebiede wat gesny en swaar bewei was, het nie doeltreffend die natuurlike komplement van nagtelike akoestiese spesies gehandhaaf nie. In natuurlike plantegroei fragmente binne plantasies, het akoestiese spesiesrykheid toegeneem met plantverskeidenheid en fragmentgrootte. Fragmente van inheemse plantegroei binne die plantasiematriks het effektief die kontras van getransformeerde landskappe met omliggende natuurlike gebiede verminder, en inheemse woudefragmente het hoogs kenmerkende akoestiese spesiesversamelings gehad. Binne die plantryke bergfynbosstreek van die Kaap Floristiese Streek, was akoestiese profielsamestelling gedoen oor gradiënte van hoogte bo seevlak, seisoen en plantegroei. Oor hierdie gradiënte, is langhoringsprinkaan akoestiese seine geïdentifiseer en gekenmerk vir die eerste keer. Dit het gelei tot die ontdekking van twee nuwe langhoringsprinkaan spesies en 'n nuwe klankvervaardiging struktuur in 'n Carabid kewer, 'n spesie wat nie voorheen bekend was om klank te produseer nie. Akoestiese diversiteit oor gradiënte van seisoen en hoogte bo seevlak het toegeneem met toenemende temperature. Variasie in klimaatstoestande oor die gradiënt van hoogte bo seevlak het variasie in seisoenale fenologie veroorsaak. Langhoringsprinkane het ook hoë frekwensie akoestiese seine benut, wat waarskynlik 'n aanpassing is om agtergrondgeraas van die wind, wat so algemeen is in hierdie gebied, te bowe te kom. Verder, ten spyte van die vervaardiging van opvallende seine vir maataantrekking en paarvorming, het langhoringsprinkane nie deel gevorm van die bakoorjakkals se dieet nie. Hierdie is 'n insekvretende, nagtelike roofdier wat gebruik maak van sy kenmerkende groot ore om klanke op te spoor wat gemaak word deur invertebraatprooi. Hierdie studie toon die waarde van die gebruik van akoestiese seine van langhoringsprinkane om akoestiese diversiteitspatrone te identifiseer oor ekologiese gradiënte en in reaksie op menslike impakte op die landskap.

Thesis (MScAgric (Conservation Ecology and Entomology)--University of Stellenbosch, 2005. / Within the Table Mountain National Park (TMNP), Western Cape, South Africa, various management practices have been undertaken in the removal of alien vegetation. While considerable success in the control of alien plants is evident from the removal of standing plants, it is not known if this effort has actually made any long-term difference in the effort to eliminate alien vegetation from the TMNP. This is because no coordinated effort has been made to assess the extent of the alien seed bank, nor the effect that clearing (including the use of fire) has on this seed store. This study investigates the extent of pre- and post-fire Acacia saligna seed banks under differing stand ages, differing clearing techniques and different habitats in the Cape Peninsula National Park. Firstly, the focus is on two alien plant management techniques: The first technique involves clearing and stacking of biomass for burning during winter (stack burn technique), the second technique involves burning of standing alien plants (standing/block burn technique) to decrease heat release at the surface. Secondly, the extent of Acacia species seed banks along the Silvermine River is also investigated with the aim of determining the extent of alien seed stores in this habitat and therefore the long-term restoration potential of the riparian corridor. The primary question addressed in the first study is: “Under what clearing technique will most of the alien seed bank be reduced?” The secondary question reads: “Is seed bank density and distribution directly related to age of dense infestation of the alien vegetation stand and habitat?” The primary question addressed in the second study is: “What is the vertical, lateral and longitudinal distribution and density of Acacia species seed banks along the Silvermine River?” The secondary question reads: “Is seed density and distribution influenced by above ground density of alien vegetation?” In both riparian and terrestrial systems, alien soil seed banks accumulate in high densities where aboveground alien Acacia vegetation is dense. Most of the seed occurs in the upper soil layer, but seed density decreases with depth with an exception of a high seed density at a low depth in one of the samples in the riparian system. Intense fires are most effective in reducing seed stores and removing aboveground alien vegetation in both riparian and terrestrial fynbos systems. After burns, both stack and stand burns have shown a significant decrease in seed density especially in the upper layers but there is still much seed that remained in the matrix area between stacks. The cooler winter burns resulted in less destructive, lower temperatures that aided higher seedling recruitment. Mature stands of Acacia saligna tend to have greater seed stores than immature stands and habitats with deep colluvial soils have a greater density and also greater vertical distribution of seeds. The vertical distribution of the riparian system differed from the fynbos terrestrial system in that seeds were found down to lower depths. Along the river, seed density also increased laterally with more seeds occurring in the terrrestrial sections than in the channel. Seed density increased with longitudinal distribution with more seeds occurring at the sites in the lower catchment than upper catchment. Managers should be aware that fire is needed to reduce the seed bank in both riparian and terrestrial fynbos systems. The cooler winter stack burns is the best option as it results in less destructive, lower temperatures that aids higher seedling recruitment. It is important to know the site history as age of dense infestation, number of fires and geology of site could influence seed bank density. In riparian systems the vertical distribution of seed is deeper than in the fynbos area. In order for clearing to be effective it is imperative that follow-up takes place and should be done prior to flowering to stop reseeding.

Thesis (MScConsEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2006. / Using the World Conservation Union’s (formerly the International Union for the Conservation of Nature) IUCN 2001 categories and criteria, the conservation status of the South African butterfly fauna has been reassessed. This study includes an assessment of the 62 globally threatened South African taxa and 1 that has a marginal distribution in this region.

Thesis (MScAgric)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The agricultural industry in South Africa is dominated by the use of insecticides. Producers rely heavily on chemicals that cause increased risk to health, the environment and ecology, rapid resistance development in key insect pests and pesticide residues on crops. The increased concern regarding the impact of these pest management practices on the environment and alternative pest management strategies are being investigated. Entomopathogenic nematodes (EPNs) have been identified as being promising biological control agents of key insect pests. The two EPN genera that have shown promise for use as biological control agents within an integrated pest management programme areSteinernema and Heterorhabditis. Commercialisation and the successful use of EPNs to control pests in North America, Australia, Europe and Asia have confirmed the effectiveness of these organisms as biological control agents. Unfortunately, EPNs in large enough numbers for commercial field applications are not yet available on the South African market. Large numbers of EPNs can be produced through either in vivo or in vitro culturing practices. The objective of this study was to streamline the in vivo production process by using two endemic EPN species, Heterorhabditis zealandica (SF41) and H. bacteriophora (SF351). These EPN isolates have been shown to be effective control agents of codling moth Cydia pomonella, false codling moth Thaumatotibia leucotreta, obscure mealybug Pseudococcus viburni, and the banded fruit weevil Phlyctinus callosus. A comparative study was conducted to identify suitable host insects for EPN production of local H. zealandica (SF41) and H. bacteriophora (SF351) strains. Hosts were selected according to their susceptibility to the two EPN species used, their general availability and the ease and cost of rearing. Wax moth larvae Galleria mellonella (WML) and mealworms Tenebrio molitor (MW) were selected as hosts. In order to produce nematodes of consistent quality, a continuous source of host insects reared on a standardised diet was required. WML and MW were each reared on five different diets in the dark at ±26°C. A superior diet for each host was selected according to the diet that produced, on average, the larvae with the highest body mass within a specific timeframe. The heaviest WML, at an average weight of 0.19 g per larva, were produced on a diet consisting of 118 g wheat flour, 206 g wheat bran, 118 g milk powder, 88 g brewer‟s yeast, 24 g wax powder, 175 ml honey and 175 ml glycerol. The heaviest MW larvae weighed, on average, 0.0154 g per larva, and were produced on a diet consisting of 100% wheat bran. To confirm the hypothesis that a linear relationship exists between the weight of a host and the number of nematodes produced from that host, a study was conducted to determine the number of H. zealandica and H. bacteriophora produced per g of host. WML, MW, codling moth larvae and false codling moth larvae were weighed individually and inoculated with the two nematode species respectively. In addition, nematode production in frozen MW and WML was tested. The number of nematodes harvested from each host was counted, and the average number of nematode progeny produced in each host was calculated. A significant linear correlation between the weight of WML and MW and the number of H. zealandica and H. bacteriophora respectively produced confirmed the hypothesis that nematode production within the specified host increases with an increase in host weight. WML produced the highest number of H. zealandica and H. bacteriophora per g of host (1 459 205 ± 113 670 and 1 898 512 ± 94 355), followed by MW larvae (836 690 ± 121 252 and 414 566 ± 67 017). Lower numbers of H. zealandica and H. bacteriophora per g codling moth (57 582 ± 10 026 and 39 653 ± 8 276) and per g false codling moth (192 867 ± 13 488 and 97 652 ± 23 404) were produced. Successful infection of a suitable insect host is one of the key factors in an efficient in vivo nematode production process. Three inoculation techniques were compared using H. zealandica and H. bacteriophora: inoculation with a pipette; shaking of hosts in the nematode inoculum; and immersion of hosts in the nematode suspension. With each inoculation technique, WML and MW were used as host larvae and were inoculated with nematodes at a concentration of 200 infective juveniles (IJs) / larva. The percentage mortality of insect hosts was determined after two days, and EPN infectivity, confirmed by colour change and dissection, after seven days. The highest percentage EPN infection was obtained using pipetting for both nematode isolates and hosts. Nematode infection rates for all nematode-host combinations obtained with pipetting were above 90%, with the exception of MW inoculation with H. bacteriophora, where the percentage of infection obtained was 76%. The current study conclusively demonstrated that variations in infection levels occur, depending on the inoculation technique used. In an additional effort to enhance infectivity during inoculation, H. zealandica, H. bacteriophora and MW were subjected to host-stressor regimes and to nematode- infectivity-enhancing additives. Three treatments, plus a control treatment, were compared. Exposing MW to 70°C tap water prior to inoculation did not increase infection levels. On the contrary, reduced infection levels were observed with host immersion in 70°C tap water followed by inoculation with H. bacteriophora, compared to the control. Only 12% infection was obtained compared to the 48% infection achieved in the control. Infection obtained using H. zealandica was 21%. Treating H. zealandica and H. bacteriophora IJs withMn2+SO4.H20 in a suspension, prior to inoculating MW, did not significantly enhance nematode virulence. Inoculation of MW with treated H. zealandica IJs led to an infection rate of 81%, compared to the control, with which 80% infection rate was obtained. Heterorhabditis bacteriophora caused 47% MW infection, compared to the control, which was subject to 48% infection. A combination of the two above-mentioned treatments did not enhance the infection levels either. Immersing MW into 70°C tap water prior to inoculation with nematodes treated with Mn2+SO4.H20 led to infection levels of 13% and 9% respectively when H. bacteriophora and H. zealandica were used. Future research is required to optimise the protocol used in this study of subjecting MW and local nematode isolates to stressor regimes. The ability of two formulations to maintain biological activity and virulence of H. zealandica was investigated. A quality standard control measure was used to measure the percentage survival and virulence of formulated H. zealandica over a period of 21 days. IJs were formulated into Pesta granules and coconut fibres, while nematodes stored in tap water served as the control. The numbers of live H. zealandica in Pesta granules and coconut fibres decreased drastically after seven days of storage. The survival of nematodes in Pesta granules dropped to 9.79% after 21 days compared to the control, where the survival rate was 79.79%. Nematode survival in coconut fibres was even lower, at 25.84% after seven days and 2.25% after 21 days. After 21 days in storage, 100%+of nematodes survived in the control for coconut fibres. The application of the standard quality control measure, which was used to determine the virulence of formulated H. zealandica, proved to be ineffective. Higher MW mortality rates were obtained in the control where no nematodes were added to larvae, compared to where nematodes were added in varying dosages. However, adjusting certain aspects in the protocol of this quality control measure specifically to accommodate local conditions could possibly make it a more effective tool for measuring endemic nematode virulence. / AFRIKAANSE OPSOMMING: Die landboubedryf in Suid-Afrika word oorheers deur die gebruik van insekdoders. Vervaardigers steun swaar op chemikalieë wat toenemend gesondheids-, omgewings- en ekologiese risiko's, asook die snelle ontwikkeling van weerstand in sleutelinsekteplae veroorsaak, en wat reste van plaagdoders op gewasse laat. Na aanleiding van toenemende besorgdheid oor die impak van hierdie plaagbestuurspraktyke op die omgewing, word alternatiewe plaagbestuurstrategieë ondersoek. Entomopatogeniese nematodes (EPNs) is geïdentifiseer as belowende biologiese beheeragente van sleutelinsekteplae. Die twee EPN genera wat belofte inhou vir gebruik as biologiese beheeragente binne 'n geïntegreerde plaagbestuursprogram is Steinernema en Heterorhabditis. Kommersialisering en die geslaagde gebruik van EPNs om insekplae te beheer in Noord-Amerika, Australië, Europa en Asië, het die doeltreffendheid van hierdie organismes as biologiese beheeragente bevestig. Ongelukkig is EPNs in groot genoeg getalle vir kommersiële aanwending in die veld nog nie op die Suid-Afrikaanse mark beskikbaar nie. Groot getalle EPNs kan deur in vivo en in vitro teling verkry word. Die doelwit van hierdie studie was om die in vivo produksieproses te stroomlyn deur die gebruik van twee endemiese EPN spesies, Heterorhabditis zealandica (SF41) en H. bacteriophora (SF351). Hierdie EPN isolate is deur navorsing bewys om doeltreffende beheeragente van kodlingmot Cydia pomonella, vals kodlingmot Thaumatotibia leucotreta, ligrooswitluis Pseudococcus viburni, en gebande vrugtekalanders Phlyctinus callosus te wees. 'n Vergelykende studie is gedoen om geskikte gasheerinsekte vir EPN produksie van plaaslike H. zealandica (SF41) en H. bacteriophora (SF351) isolate te vind. Gashere is geselekteer op grond van vatbaarheid vir die EPN spesie wat gebruik word, en algemene beskikbaarheid en gemak en koste van teling. Wasmotlarwes Galleria mellonella (WML) en meelwurms Tenebrio molitor (MW) is as gashere gekies. Ten einde nematodes van konsekwente kwaliteit te teel, word 'n deurlopende bron van gasheerinsekte benodig wat op 'n gestandaardiseerde dieet voed. WML en MW is onderskeidelik op vyf verskillende diëte geteel by ±26°C in die donker. Die beste dieet vir elke gasheer is gekies op grond van die dieet wat, gemiddeld, die swaarste larwes binne 'n spesifieke tydsraamwerk opgelewer het. Die swaarste WML, teen 'n gemiddelde massa van 0.19 g per larwe, is geteel op 'n dieet wat bestaan het uit 118 g koringmeel, 206 g semels, 118 g melkpoeier, 88 g brouersgis, 24 g verpoeierde was, 175 ml heuning en 175 ml gliserol. Die swaarste MW larwes het gemiddeld 0.0154 g per larwe geweeg en is geteel op 'n dieet van 100% semels. Ten einde die hipotese te bevestig dat 'n lineêre verwantskap bestaan tussen die massa van 'n insekgasheer en die aantal nematodes wat deur daardie gasheer geproduseer word, is 'n studie gedoen om die aantal H. zealandica en H. bacteriophora per gasheergram te bepaal. WML, MW, kodlingmotlarwes en vals kodlingmotlarwes is individueel geweeg en met infektiewe larwes van die twee onderskeidelike EPN spesies geïnokuleer. Daarbenewens is die vermeerdering van nematodes in bevrore MW en WML ook getoets. Die aantal nematodes wat in elke gasheer geoes is, is getel, en die gemiddelde nematode-afstammelinge in elke gasheer bereken. 'n Beduidende lineêre korrelasie tussen die massa van WML en MW en die aantal H. zealandica en H. bacteriophora wat onderskeidelik geproduseer is, het die hipotese bevestig dat nematode-vermeerdering binne hierdie gashere toeneem namate die gasheermassa toeneem. WML het die meeste H. zealandica en H. bacteriophera per gasheergram opgelewer (1 459 205± 113 670 en 1 898 512± 94 355 onderskeidelik), gevolg deur MW larwes (836 690± 121 252 en 414 566± 67 017 onderskeidelik). Laer getalle H. zealandica and H. bacteriophora per gram kodlingmot (57 582 ± 10 026 en 39 653 ± 8 276) en per gram vals kodlingmot (192 867 ± 13 488 en 97 652 ± 23 404) is egter geproduseer. Een van die sleutelfaktore vir die doeltreffendheid van die in vivo vermeerdering van nematodes is geslaagde gasheerinfeksie. Drie inokulasietegnieke is dus geëvalueer en vergelyk deur H. zealandica en H. bacteriophora te gebruik: inokulasie met 'n pipet, skud van gashere in 'n nematode-inokulum, en gasheerindompeling in 'n nematode-suspensie. WML en MW is as gashere gebruik vir elke inokulasietegniek, en is geïnokuleer met nematodes wat uit 'n konsentrasie van 200 infektiewe larwes (ILs) / insek larwe bestaan het. Die persentasie dooie insekgashere is na twee dae bepaal, en infeksie soos bevestig deur kleurverandering en disseksie, na sewe dae. Die hoogste persentasie infeksie deur sowel nematode-isolate as gashere te gebruik, was met die pipet-tegniek. Die infeksiekoerse vir alle nematode-gasheerkombinasies met die pipet-tegniek was hoër as 90%, met die uitsondering van MW-inokulasie met H. bacteriophora, waar die infeksie 76% was. Hierdie studie toon dat afwykings voorkom in die mate van gasheerinfeksie, na gelang van die inokulasietegniek wat gebruik is. In 'n bykomende poging om infeksie na inokulasie te verhoog, is H. zealandica, H. bacteriophora en MW onderwerp aan stressors en bymiddels om nematode-infeksie te bevorder. Drie behandelings, asook 'n kontrole-behandeling, is vergelyk. Infeksievlakke het nie verhoog deur MW voor inokulasie aan kraanwater van 70°C bloot te stel nie. Inteendeel, laer infeksievlakke is opgemerk waar gashere in kraanwater van 70°C gedompel is en daarna met H. bacteriophora geïnokuleer is, vergelyke met die kontrole. Gasheerinfeksie van slegs 12% is verkry, vergelyke met 48% in die kontrole. Infeksie van 21% is met H. zealandica verkry. Die virulensie van nematodes het nie beduidend toegeneem deur H. zealandica en H. bacteriophora IL in 'n suspensie met Mn2+SO4H20 te behandel voor MW geïnokuleer is nie. Inokulasie van MW met behandelde H. zealandica IL het tot 'n infeksie van 81% gelei, vergelyke met die kontrole waar 'n infeksie van 80% behaal is. H. bacteriophora het 'n MW-infeksie van 47% veroorsaak, vergelyke met die kontrole se infeksiekoers van 48%. 'n Kombinasie van die twee bogenoemde behandelings het eweneens nie gasheerinfeksievlakke verhoog nie. Die indompeling van meelwurms in kraanwater van 70°C voor inokulasie met nematodes wat met Mn2+SO4H20 behandel is, het tot gasheerinfeksie van 13% en 9% onderskeidelik gelei wanneer H. bacteriophora en H. zealandica gebruik is. Toekomstige navorsing is nodig om die protokol te verbeter wat in hierdie studie gebruik is om MW en plaaslike nematode-isolate aan stressors te onderwerp. 'n Ondersoek is gedoen na die vermoë van twee formulasies om biologiese aktiwiteit en virulensie van H. zealandica te onderhou. 'n Kwaliteitsstandaardtegniekis gebruik om weekliks die persentasie oorlewing en virulensie van geformuleerde H. zealandica oor 'n tydperk van 21 dae te meet. IL is in Pesta korrels en klappervesel geformuleer, terwyl nematodes in kraanwater gedien het as kontrole. Die aantal lewende H. zealandica in Pesta korrels en klappervesel het drasties verminder na sewe dae in die formulasie. Oorlewing van nematodes in Pesta korrels het gedaal tot 9.79% na 21 dae vergyleke met die kontrole, waar 79.79% oorleef het. Nog minder nematodes - 25.84% - het na sewe dae in die klappervesel oorleef, en slegs 2.25% na 21 dae. Na 21 dae van berging het 100%+ van nematodes oorleef in die kontrole vir klappervesel. Die toepassing van die kwaliteitsstandaardtegniek om die virulensie van geformuleerde H. zealandica te bepaal, het ondoeltreffend geblyk. Verhoogde MW sterftesyfers is verkry in die kontrole waar geen nematodes by die inseklarwes gevoeg is nie, vergelyke met die byvoeging van hoër dosisse nematodes. Nietemin, die aanpassing van sekere aspekte in die protokol van hierdie kwaliteitsbeheermeting om spesifiek plaaslike toestande in ag te neem, sou dit moontlik 'n meer doeltreffende middel kon maak om die virulensie van endemiese nematodes te bepaal.

Thesis (MScConsEcol (Conservation Ecology and Entomology))--Stellenbosch University, 2008. / The fynbos eco-region in the Western Cape lowlands has been extensively transformed by anthropogenic activities such as agriculture and urban development, as well as invasive alien plants. Elandsberg Private Nature Reserve and Farms lies on Swartland Alluvium Fynbos and has been largely fragmented by agricultural crop production, whilst Riverlands Nature Reserve together with the Pella Research Site, which lie on Atlantis Sand Fynbos, are under severe threat from the invasive woody alien Port Jackson Willow (Acacia saligna) which forms dense stands in the lands adjacent the nature reserve. Habitat transformation has resulted in subsequent loss of habitat and a reduction in habitat value for small mammal communities by creating a mosaic of optimal and sub-optimal habitats. The success of A. saligna is, in part, attributed to its production of copious amounts of small hard-shelled seeds and well established soil seed banks. In the first part of this study we investigated the effect of habitat transformation on resident small mammal communities by comparing small mammal species richness, diversity and abundance between natural and transformed habitats as well as between the two vegetation types. We also investigated the population demographics of the striped mouse (Rhabdomys pumilio) in the different habitats. Our study shows that whilst fragments of natural habitats, especially at Riverlands and Pella, may be playing an important role in harbouring rare and possibly endangered species, transformed habitats are also important as secondary habitats providing both cover as well as seasonal food resources. Reproduction and body condition in R. pumilio were dependent on seasonal changes such as availability of water and food resources in the habitats. The second part of this study was carried out to investigate the effect of alien plant invasion on the resident small mammal communities at Riverlands Nature Reserve and to determine the role of small mammals in the removal and predation of A. saligna seeds. Rodent species richness, diversity and abundance were very low in the A. saligna stands compared to the adjacent fynbos vegetation. The interaction of rodents with seeds (removal or predation) was dependent upon seed size and seed abundance in the habitats. Whilst rodents may play an important role in predator limitation in the acacias, it is also possible that they may be playing a significant role in dispersing the seeds of acacias into the fynbos. More work is required to fully understand the role small mammals play in seed predation, dispersal and limitation in alien invaded fynbos systems.