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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Exploring meaningful nature experience, connectedness with nature and the revitalization of transformative education for sustainability

Zylstra, Matthew J. 04 1900 (has links)
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.
42

Development of a Biotope Quality Index

Bredenhand, Emile 04 1900 (has links)
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.
43

Acoustic profiling of the landscape

Grant, Paul Brian Charles 04 1900 (has links)
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.
44

Management of Acacia species seed banks in the Table Mountain National Park, Cape Peninsula, South Africa

Jasson, Rene 12 1900 (has links)
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.
45

Small mammal communities in the transformed landscapes of the Western Cape lowlands and their role in alien invasion into fynbos remnants

Mugabe, Chapangara James 12 1900 (has links)
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.
46

Spatial and temporal distribution of false codling moth across landscapes in the Citrusdal area (Western Cape Province, South Africa).

Stotter, Robert L. 03 1900 (has links)
Thesis (MScAgric (Conservation Ecology and Entomology)--University of Stellenbosch, 2009. / The false codling moth (FCM), Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), is an indigenous pest of citrus fruit in southern Africa, and is a pest of high phytosanitary concern, impacting negatively on the export of fresh citrus fruit from South Africa to some international markets. FCM is a particularly serious pest in the Citrusdal area in the Western Cape Province of South Africa. FCM is known to infest most types of citrus, with navel oranges being particularly prone to attack, whereas lemons are not considered to be a favoured host. Conventional control strategies that rely on the use of insecticides are of limited use due to high levels of insecticide resistance in FCM populations. Mating disruption, the Sterile Insect Technique (SIT) and the integration of different control techniques are options that are currently being adopted. Little is known about FCM host preferences in this geographical area, or about its dispersal capacity. The ability of FCM to migrate between various host patches, including citrus orchards and indigenous fynbos vegetation, and its ability to maintain a viable population in alternative host plants when there is no fruit available for infestation in citrus orchards has not been well studied. Knowledge of these largely behavioural facets is important in planning an effective control strategy for FCM. Towards addressing this dearth of knowledge, FCM pheromone traps were set out in transects in the Citrusdal area. These transects included citrus orchards, and extended beyond citrus orchards, to include a range of habitat types and elevational gradients. This provided a grid to assess the spatial and temporal distribution of male FCM in the area. In addition, intensive sampling and inspection of potential host plant material was undertaken in the area in an attempt to identify any alternative host plants.
47

Habitat use and diet selection of reintroduced white rhinoceros (Ceratotherium simum) in Pafuri, Kruger National Park

Pedersen, Gayle 03 1900 (has links)
Thesis (MSc (Conservation Ecology and Entomology))--Stellenbosch University, 2009. / ENGLISH ABSTRACT: In 2005, six white rhinoceros (Ceratotherium simum) were reintroduced into Pafuri, in the far northern section of Kruger National Park (KNP), South Africa, as part of a large mammal reintroduction project. All six individuals were fitted with horn radio transmitters. Rhinos have been absent from Pafuri for over a century, and this project aimed to establish a breeding nucleus in the area. The aim of this study was to monitor post-release movement and habitat use of these animals within the 203 km2 study area and assess the short term success of the re-introduction project as well as the suitability of the five landscape types in Pafuri as a habitat for white rhinoceros. Habitat suitability and selection was assessed at two ecological hierarchical scales: 1) landscape system, analysed further down to the spatial scale of range and territory establishment, and 2) feeding station for diet selection. Rhinos were tracked for 12 months and a database of 719 sighting records was compiled. These data were used to determine the utilisation of and preference between the Pafuri landscape types, using preference indices that compare utilisation versus availability. An a-LoCoH nonparametric kernel method was used to calculate home ranges and utilisation distributions of each rhino. Feeding surveys were attempted by backtracking along fresh rhino feeding paths and recording the grass species present and eaten in 0.7 m x 0.7 m quadrats. Faecal samples were collected and analysed using microhistological techniques and dietary composition was assessed for each rhino. Landscape preference analyses showed that the rhinos favoured Colophospermum mopane Shrubveld on calcrete in the dry season, and the Punda Maria Sandveld in the wet season. The territory establishment of the dominant bull was substantially larger (44.8 km²) than those of adult male rhinos in the rest of KNP. Ranging areas of the mature females (17 – 25.4 km²), were consistent with sizes of previous studies. The two sub-adults ranged far more extensively, establishing an 84.1 km² annual range during the study period. The annual diet consisted of mostly perennial grass species, with moderate grazing value species dominating for most of the year. Dietary analyses showed that Schmidtia pappophoroides, Eragrostis superba, Enneapogon cenchroides, Cenchrus ciliaris and Stipagrostis uniplumis were the primary grass species consumed. vii This study demonstrated that the Pafuri rhinos are behaving similarly to rhinos established in other areas, with movements around the landscapes being primarily influenced by rainfall and permanent water sources, and the high quality grazing that is more abundant in the wet season. Their range and territory sizes were inevitably large, for a low density area, but not uncommonly so. The most significant outcome of this study was the preference shown for the Colophospermum mopane Shrubveld on calcrete landscape that is classed as unique within South Africa, and was also ranked as ‘avoided’ by the earlier KNP studies into landscape preferences of rhinos. The grass cover in Pafuri, although sparse and very dry, contained a diversity of low to high grazing value grasses that the rhinos appeared to exploit to the best of their ability. The abundance of moderate grazing value species in their diets, and the low number of low grazing value species suggests that they are maximising the opportunities to graze on nutritious grasses when they are available. Our findings suggest that the Pafuri area is suitable for the establishment of a small breeding nucleus of white rhinos. The abundance of permanent water, in the form of springs, is a great advantage however, the potential for bush encroachment into grasslands in areas of such low rainfall needs to be considered if the population continues to grow at the current rate. The birth of two new calves in 2008 confirms that these rhinos have settled and adapted to their new habitat, and is a very promising sign for the future of this increasing subpopulation. / AFRIKAANSE OPSOMMING: In 2005 is ses wit renosters (Ceratotherium simum) hervestig in Pafuri in die noordelike gedeelte van die Kruger Nasionale Park (KNP), Suid-Afrika, as deel van ‘n groot soogdier hervestigings projek. Al ses individue is gemerk met horing radioseintoestelle. Renosters kom vir al meer as ‘n honderd jaar nie meer in Pafuri voor nie en hierdie projek was daarop gemik om ‘n teel-nukleus in hierdie gesied te vestig. Die doel van hierdie studie was om die verspreiding van die renosters na loslating en habitat-gebruik binne die 203 km2 studie-omgewing te monitor, om die korttermyn sukses van die hervestigings program te evalueer en ook te kyk na die gepastheid van die vyf landskap-tipes in Pafuri as ‘n geskikte habitat vir die wit renosters. Habitatgepastheid en seleksie is geëvalueer volgens twee ekologiese hiërargiese skale: 1) landskapsisteem, wat in meer resolusie tot die ruimtelike skaal van reikwydte en omgewingsvestiging geanaliseer is, en 2) voedings-stasie vir dieet-seleksie. Renosters is vir 12 maande gevolg en ‘n databasis wat 719 waarneming-rekords bevat, is opgestel. Laasgenoemde data is gebruik om die gebruik en voorkeur vir die Pafuri landskap tipes te bepaal met behulp van voorkeur-indikators wat die gebruik met beskikbaarheid vergelyk het. ‘n a-LoCoH nie-parametriese kern metode is gebruik om die reikwydte en gebruiksverspreidings van elke renoster te bereken. Voedingsopnames is gedoen deurdat vars renoster voedings-paadjies terugwaarts gevolg is en die grasspesies teenwoordig en waarop gevoed is, in 0.7 m x 0.7 m kwadrante te bepaal. Mismonsters is versamel en geanaliseer deur gebruik te maak van mikro-histologiese tegnieke en voedingswaarde-samestellings is vasgestel vir elke renoster . Landskapsvoorkeur analises dui daarop dat die renosters in die droë seisoen Colophospermum mopane struikveld wat op kalkreet groei verkies en die Punda Maria Sandveld in die reën seisoen. Die terrein vestiging van die dominanate bul was aansienlik groter (44.8 km²) in vergelyking met die volwasse bul renosters in die res van die KNP. Reikwydte van die volwasse koeie (17 – 25.4 km²) was ooreenstemmend met dié van vorige studies. Die reikwydte van die twee subvolwassenes het baie meer gevarieer, deurdat ‘n 84.1 km² jaarlikse reikwydte gedek was binne die studie periode. Die jaarlikse dieet het meestal bestaan uit meerjarige ix grasspesies, met spesies met matige weidingswaarde wat oorheers vir meeste van die jaar. Voedingswaarde analises dui daarop dat Schmidtia pappophoroides, Eragrostis superba, Enneapogon cenchroides, Cenchrus ciliaris en Stipagrostis uniplumis die primêre gras spesies was waarop gewei word. Die studie het bewys dat die Pafuri renosters soortgelyke gedragspatrone vertoon het as renosters in ander gevestigde gebiede, deurdat bewegings binne die landskap hoofsaaklik beïnvloed word deur reënval en permanente waterbronne, asook die hoë gehalte weidingsbronne beskikbaar gedurende die reën seisoen. Hulle reikwydte- en terrein-groottes was uiteraardelik groot vir ‘n lae-digtheid areas, maar dit is nie buitengewoon nie. Die mees betekenisvolle gevolgtrekking van die studie was die voorkeur vir die Colophospermum mopane struikveld op kalkreet landskappe wat beskou word as uniek aan Suid-Afrika, en wat ook beskou was as ‘vermy’ deur vroër KNP studies tov. landskap voorkeure spesifiek vir renosters. Die grasbedekking in Pafuri, alhoewel yl en baie droog, het tog oor ‘n verskeidenheid grasse beskik wat van lae tot hoë weidings waarde het, en wat die renosters tot die beste van hulle vermoë benut het. Die oorvloedige teenwoordigheid van beide spesies met matige weidingswaarde in hulle dieët en die lae hoeveelheid van spesies met lae weidingswaarde, impliseer dat hulle die geleentheid om op voedingsryke grasse te voed ten volle benut wanneer dit beskikbaar is. Ons resultate dui daarop dat die Pafuri omgewing geskik is vir die vestiging van ‘n klein teel-nukleus van wit renosters. Die oorvloedige teenwoordigheid van permanente waterbronne in die vorm van fonteine is ‘n groot voordeel, maar die kans vir bosindringing in hierdie grasveld-gebiede met lae reënval moet oorweeg word sou die populasie aanhou toeneem teen die huidige tempo. Die geboorte van twee nuwe kalfies in 2008 staaf die moontlikheid dat die renosters gevestig en aangepas het in hulle nuwe habitat, wat ‘n baie belowende teken is vir die toekoms van die groeiende subpopulasie.
48

Soil nitrogen and phosphorus depletion as a means of restoring degraded lowland fynbos ecosystems invaded by alien grasses

Ruwanza, Sheunesu 03 1900 (has links)
Thesis (MSc (Conservation Ecology and Entomology))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: Much of South African lowland fynbos vegetation has been transformed by agriculture and invasive alien grass species. The artificial reduction of plant available N and P levels in soils, through the addition of carbon and calcium respectively, may provide a means of retarding the growth of alien grasses stimulated by soil nutrient enrichment. Furthermore, the competitive advantage of native lowland fynbos species adapted to nutrient impoverished soils may be increased by these additions. The above premise was tested in both field- and greenhouse-based trials by applying systemic and contact herbicides to reduce the large alien invasive grass biomass. This was followed by the addition of C as sucrose and Ca as gypsum to reduce plant available N and P respectively in the soils. The effects of these combined herbicide and soil nutrient amendment treatments on plant physiology and growth were examined in both resident alien and indigenous species and in several herbaceous and woody native species introduced as seeds and seedlings. Also, soils sampled from the different treatments in both trials were chemically analyzed. There was a total absence of seedling recruitment from seeds of all 9 indigenous species sown into soils in the field-based trial while introduced juveniles of another 9 indigenous species displayed a high mortality during the dry summer season. These detrimental effects were less severe in the greenhouse-based trial which received more regular watering and where successful seedling recruitment from seeds sown occurred in four indigenous species. Sucrose additions, both exclusively and in combination with gypsum, caused significant reductions in foliar chlorophyll, photosystem II (PSII) function and above-ground biomass of most resident and introduced alien and indigenous species. These reductions were less prominent where herbicides were applied, a possible consequence of N and P supplementation of soils by the decomposing plant biomass. This was supported by the elevated soil K, Na and N concentrations measured in soils where contact and systemic herbicides were applied. However, no significant changes in soil N or P were apparent following sucrose and gypsum additions respectively, the latter attributed to the acidic soils which precluded the formation of insoluble P complexes. A second study tested the hypothesis that exogenous sucrose addition to soils inhibits plant growth by stimulating soil microbial biomass which accumulates soil nitrogen rendering it unavailable to plants. Two native, early seral species (Dimorphotheca pluvialus (L.) Moench and Ursinia anthemoides (L) Poir. subsp anthemoides) were cultured in heat sterilized (2200C for 72 hours) and non-sterilized soils in a greenhouse under four different levels of sucrose (0, 100, 200 and 300 g m-2) supplied monthly over a four-month active growing period. Foliar chlorophyll iii contents, photosystem II (PSII) efficiencies, shoot and root lengths and dry mass, inflorescence numbers and N and P contents were measured in the plants, and N and P contents and bacterial cell and coliform numbers analyzed in the soils. Both D. pluvialis and U. anthemoides displayed significant reductions in PSII efficiency, chlorophyll content, accumulation of biomass and N and P in response increased levels of sucrose, which initially seemingly supported the hypothesis as these reductions were of substantially greater magnitude in plants cultivated in non-sterilized than sterilized soils. Despite this, there was no evidence of any significant increases in bacterial and coliform cell numbers in response to increased levels of sucrose supplied or any significant reductions in soil N and P contents following sucrose additions in both sterile and non-sterilized soils. Greater numbers of bacteria and coliforms were measured in sterilized than non-sterilized soils which corresponded with reduced soil N contents but these were not reflected in like changes in plant PSII efficiency and growth and total amounts of N taken up by plants which displayed massive increases in sterilized soils. The findings did not support the hypothesis and pointed to an abiotic mechanism of sucrose inhibition of plant photosynthesis and growth. The study concludes that the suitability of adding sucrose and gypsum to degraded renosterveld ecosystem soils to promote the competitiveness of native taxa against alien grasses is dubious. Other restoration alternatives such as natural re-colonization, transfer of soils containing viable seeds from pristine communities and top soil removal should be considered. / AFRIKAANSE OPSOMMING: Baie van Suid Afrika se laagland fynbos plantegroei is verander deur landbou en uitheemse indringer grasspesies. Die kunsmatige reduksie van plantbeskikbare N en P vlakke in die grond deur die toevoeging van koolstof en kalsium onderskeidelik, kan ’n metode wees om die groei van indringer grasse te vertraag, wat gestimuleer word deur grondvoedingstofverryking. Die kompeterende voordeel van die inheemse laagland fynbosspesies wat aangepas is tot voedingstofarme grond kan verhoog word deur die toevoegings. Bogenoemde postulaat is in beide die veld- en die glashuis-gebaseerde eksperimente getoets deur die aanwending van sistemiese en kontak onkruiddoder om die groot indringer grasbiomassa te verminder gevolg deur die byvoeging van C as sukrose en Ca as gips om die plantbeskibare N en P onderskeidelik te verminder in die grond. Die effekte van die gekombineerde onkruiddoder en grondvoedingstof verbeteringsbehandelings op die fisiologie en groei van die plante is ondersoek in beide inheemse- en residente indringerspesies asook in verskeie kruidagtige- en houtagtige inheemse spesies wat aangeplant was as sade en saailinge. Grondmonsters van die verskillende behandelings in beide studies was versamel en was chemies geanaliseer. Daar was ’n definitiewe afwesigheid van nuwe saailinge van sade van al nege indringerspesies wat gesaai was in grond in die veldgebaseerde studie, en saailinge van nog nege inheemse spesies het ’n hoë mortaliteit getoon gedurende die droë somerseisoen. Hierdie skadelike effekte was minder ernstig in die glashuisgebaseerde studie wat meer benat was, en waar nuwe saailinge suksesvol geproduseer was deur sade in vier inheemse spesies. Sukrose byvoegings, beide uitgesluit en in kombinasie met gips, het ’n afname in blaarchlorofil, fotosisteem II en bogrondse biomassa van die meeste van die residente en aangeplante indringer- en inheemse spesies getoon. Hierdie afnames was minder prominent waar onkruiddoder aangewend was, ’n moontlke oorsaak van N en P aanvulling van grond deur die verrottende plantbiomassa. Dit word ondersteun deur verghoogde grond K, Na en N konsentrasies, gemeet in grond waar kontak en sistemiese onkruiddoder toegevoeg was. Geen noemenswaardige veranderinge in grond N of P was sigbaar na byvoeging van sukrose en gips onderskeidelik nie. Laasgenoemde het bygedra tot suuragtige grond wat die formasie van onoplosbare P komplekse verkom het. ‘n Tweede studie het die hipotese getoets waar eksogene sukrose byvoeging tot grond plantegroei inhibeer deur die grond mikrobe biomassa te stimuleer wat akkumuleer wat in grond stikstof en dit nie beskikbaar maak vir plante nie.Twee inheemse vroeë intermediêre stadium spesies (Dimorphotheca pluvialus (L.) Moench en Ursinia anthemoides (L) Poir. subsp v anthemoides) was gekweek in hitte gesteriliseerde grond (2200 C vir 72 uur) en in nie-gesteriliseerde grond in ’n glashuis onder vier verskillende vlakke van van sukrose (0, 100, 200 en 300 g m-2) bygevoeg maandeliks oor ‘n 4 maande aktiewe groei periode. Blaarchlorofilinhoud, fotosisteem II (FS II) doeltreffendheid, groeipunt en wortel lengte en droë massa, blomgetalle en N en P inhoud was gemeet in die plante sowel as N en P inhoud en bakteriële sel en kolivorm getalle was geanaliseer in die grond. Beide D. pluvialis en U . anthemoides het ’n afname getoon in FS II doeltreffendheid, chlorofilinhoud, biomassa akkumulasie, N en P response op verhoogde vlakke van sukrose, wat aanvanklik aangetoon het dat dit die hipotese ondersteun want hierdie afnames wat heelwat groter in plante wat gekweek was in ongesteriliseerde grond as in gesteriliseerde grond. Daar was geen toename in baketriële en kolivorm sel getalle in rssponse tot verhoogde vlakke van sukrose byvoegings of enige noemenswaardige in grond N en P inhoud na byvoeging van sukrose in beide steriele en nie-steriele grond nie. Groot getalle bakterieë en kolivorme was gemeet in gesteriliseerde grond as in ongesteriliseerde grond. Dit korrespondeer met verminderde grond N inhoud maar dit was nie gereflekteer in veranderinge in plant FS II doeltreffendheid, groei en die totale hoeveelhede N wat opgeneem was deur plante wat ’n massiewe toename getoon het ongesteriliseerde grond nie. Hierdie bevindings het nie die hipotese ondersteun nie en het gewys na ’n abiotiese meganisme van sukrose inhibisie van plant fotosintese en groei. Die studie lei dus af dat die geskiktheid om sukrose en gips by te voeg tot gedegradeerde renosterveld ekosisteemgrond om kompetisie tussen inheemse plante en indringer grasse te promoveer, twyfelagtig is. Ander restorasie alternatiewe soos natuurlike herkolonisasie, oordrag van grond wat lewensvatbare sade bevat van onbeskadigde gemeenskappe en bogrond verwydering word oorweeg.
49

Elephant movements and human-elephant conflict in a transfrontier conservation area

Von Gerhardt-Weber, Katharina E. M. 03 1900 (has links)
Thesis (MScConEcol)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: In this thesis I explore how elephant movements are impacted by human activity within the context of the proposed Kavango-Zambezi Transfrontier Conservation Area (KAZA TFCA) in southern Africa. Being a wide-ranging species, the movements of elephants could be an excellent indicator as to the success of TFCAs in supporting species persistence in an anthropogenic matrix. Understanding which areas beyond protected area boundaries are of heightened conservation importance can provide managers and governments with insights for the management of the elephant population of KAZA TFCA, and assist managers and governments in prioritising conservation efforts. Satellite radio collar data were used to model long-range elephant movement within KAZA TFCA. Movement was compared between land use types (protected and nonprotected areas). Home ranges, core areas and seasonal ranges were calculated from collar data. Core and non-core areas were tested for significant differences in distance to settlements, rivers, protected area, AFRI and elevation as these spatial and ecological variables are believed to play a role in elephant habitat selection. Short-range elephant movements were examined in a heterogeneous, patchy landscape mosaic of settlements and agricultural fields, remnant forest patches, and secondary forests which were surrounded on three sides by protected areas. Elephant penetration of the anthropogenic matrix through the use of pathways was explored through ground-based surveys, and the impact of pathways use on human-elephant conflict calculated. I found that elephant behavioural plasticity allows for their persistence in a spatially heterogeneous landscape. Elephants, especially bulls, penetrated the landscape matrix beyond protected area boundaries. Land use planning initiatives are needed to identify and protect reachable core zones/stepping stones of quality habitat outside of protected areas, particularly in riparian zones. Differing male and female ranging behaviour within the landscape matrix may require separate land use management strategies: bulls travelled at night in non-protected areas at speeds that were four times faster than in protected areas, and made use of core zones necessary for species persistence in a fragmented landscape. A habitat corridor in the Zambian West Zambezi Game Management Area was identified. I found that during short range movements in heterogeneous environments, elephants made use of pathways. Pathways may facilitate penetration of the anthropogenic matrix and optimize foraging strategies by connecting predictable resources, such as crop fields, with landscape features such as preferred shelter/ resting areas, crossing points at roads and preferred drinking spots. Pathways were found to be the only significant spatial variable in crop-raiding. Elephants foraged randomly while in homogenous crop patches, but when travelling through a heterogeneous environment (entering or leaving agricultural locales), movement was directional and non-random. Lastly I suggest that crop attractiveness may be enhanced by water availability. Results indicated that at both the landscape and the regional scale, repeat elephant movements to core zones and along elephant pathways provided landscape ecological variables that need to be considered by conservation managers in land use planning. In addition, research on spatial awareness and navigational capabilities with regards to pathway use by elephants should be encouraged, as this research topic has been largely unexplored in the scientific literature. / AFRIKAANSE OPSOMMING: In hierdie tesis verken ek die moontlike impak van menslike aktiwiteite op olifant beweging binne die beoogde Kavango-Zambezi Oorgrens Bewaringsarea (KAZA TFCA) in suider-Afrika. Olifante is wydlopende spesies, en dus kan hul ruimtelike strekking ‘n uitstekende indikator wees van die sukses van oorgrens bewaringsareas in terme van die ondersteuning wat dié programme bied om spesies se volharding in ‘n antropogeniese matriks te verseker. Besturrders en regerings kan insig verkry deur te besef watter areas buiten die in beskermde gebiede, van verhoogde bewarings belang in KAZA TFCA is. Hierdie insig verleen ook bystand aan bestuurders en regerings met die prioritisering van bewarings inisiatiewe. Satelliet-radio nekband data was gebruik om olifante se langtermyn ruimtelike beweging binne die KAZA TFCA te modelleer. Olifant beweging was vergelyk tussen verskillende grondgebruik tipes (beskermde en onbeskermde areas). Tuistestrekking, kern areas asook seisoenale strekking was bereken vanaf nekband data. Kern en nie-kern areas was getoets vir betekenisvolle verskille in afstand vanaf nedersettings, riviere, berskermde gebiede, AFRI, en hoogte bo seevlak, omdat hierdie ruimtelike en ekologiese veranderlikes ‘n belangrike rol mag speel in olifant habitat seleksie. Kortafstand olifant bewegings was bestudeer in ‘n heterogene, gelapte landskap mosaïek van nedersettings en landbougrond, oorblywende woudareas, en sekondêre woude waarvan drie sye grens aan bekermde areas. Olifant indringing binne die antropogeniese matriks deur die gebruik van weë/toegangsweë was verken deur middel van landgebaseerde opnames, waarvolgens die impak van olifante se gebruik van hierdie paaie op mens-olifant konflik bereken kon word. My bevindinge wys dat plastisiteit in olifant gedrag dra by tot hul voortbestaan in ‘n ruimtelik heterogene landskap. Olifante, maar meer spesifiek olifantbulle, penetreer wel die landskap matriks buite beskermde area grense. Grondgebruik beplannings inisiatiewe word dus benodig om bereikbare kern areas van kwaliteit habitat buite beskermde areas te identifiseer en te beskerm – veral in rivieroewer sones. Verskille in bul en koei ruimtelike strekking gedrag binne die landskap matriks, mag afsonderlike bestuur stratgieë vereis: bv. bulle beweeg vier keer vinniger in die aand in onbeskermde areas teenoor in beskermde gebiede, daarby maak hulle ook gebruik van kern areas wat kardinaal is vir die voortbestaan van spesies in gefragmenteerde landskappe. ‘n Habitat deurgang was geïdentifiseer in die Zambiese Wes-Zambesie Wildbestuurarea. Die studie het gevind dat olifante gedurende kortafstand bewegings in heterogene omgewings gebruik maak toegangsweë. Toegangsweë mag penetrasie van die antropogeniese matriks fasiliteer, en verleen ook dat olifant weidingstrategieë die optimum bereik deur voorspelbare hulpbronne soos gewaslanderye te konnekteer met landskap eienskappe soos voorrang skuiling/rusareas, kruisingspunte by paaie, asook voorrang drinkplekke. Toegangsweë was gevind om die enigste betekenisvolle ruimtelike veranderlike in gewasstrooptogte te wees. Olifante wei lukraak in homogene gewaslanderye, maar in teenstelling, wanneer hulle deur ‘n heterogene omgewing beweeg het (binnegang of uittog uit landbou lokaliteite) was die beweging gerig. Laastens, die studie stelvoor dat gewas aantreklikheid verhoog kan word deur water beskikbaarheid. Resultate dui aan dat by beide die landskap- en streekskaal verskaf herhaalde olifant beweging na kern areas en langs olifants togangsweë, landskap ekologiese veranderlikes wat in ag geneem moet word deur bewaringsbestuurders tydens grondgebruik beplanning. Bykomend, navorsing op die ruimtelike bewustheid en navigasie vermoëns van savannah olifante met betrekking tot die gebruik van toegangsweë, moet aangemoedig word aangesien hierdie onderwerp grootliks onverken is in wetenskaplike literatuur.
50

Arthropods associated with commercial Proteaceae in the Western Cape Province, South Africa

Sasa, Archbold 03 1900 (has links)
Thesis (MSc)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The commercial cultivation of Proteaceae is an important industry in the Western Cape, however, farmers are challenged with arthropod infestation which compels them to solely rely on chemical pesticides. Past studies in South Africa have shown that Proteaceae comprise a rich and diverse arthropod fauna. However, as most of these studies were conducted on wild Proteaceae, they may not be representative of cultivated proteas. Moreover, most of these species remained unidentified due to lack of identification expertise. These past studies, however, form a useful baseline for arthropod studies in proteas, e.g. the feeding guilds found in proteas. The aim of this research was to conduct an intensive and extensive survey of the arthropod-fauna associated with commercially-cultivated proteas across an entire year. Specifically, this survey was designed to document the composition of the arthropod fauna (creating a comprehensive reference collection for pest management purposes) and to assess whether the arthropod fauna differed between seasons and pesticide treatments. Infructescences, inflorescences and foliage of mainly commercial Proteaceae were sampled for arthropods seasonally for a period of twelve months by collection of plant material and direct searching. Seven commercial protea blocks, and a wild protea block (remnant patch of fynbos vegetation), were used as the sampling sites, and two sprayed blocks were used for assessing pesticide efficacy. Individual arthropods were identified as far as possible, with 37% identified to species level. A species accumulation curve showed that rare (minor) arthropod species made up of 70% of arthropods occurring in cultivated proteas. More than 8 700 individuals from more than 140 species and about 80 families were collected and identified, revealing that cultivated proteas have a rich and diverse insect fauna. These arthropods represent the full range of plant-feeding guilds: leaf miners, leaf chewers, flower bud borers, sap suckers and seed feeders. Flower visitors/free living guild was the most abundant (72%) and speciose (25%). In addition to phytophages, there was a large suite of insect predators and parasitoids. A large number of the arthropods were endemic to the Cape Floristic Region (CFR) and some (7.86%) have a pest status, in that they cause significant damage to the protea plants (for example, 60% of Safari sunset cultivar (Leucadendron salignum x L. laureolum) new flush stems and leaves were affected by Epichoristodes acerbella (Tortricidae). Capys alphaeus (Lycaenidae) and Phyllocnistis sp. (Phyllocnistidae) appear to be specialist pests, as they attack mainly Protea cynaroides and Susara cultivar (Protea magnifica x P. susannae) respectively. Arthropod abundance did not differ significantly between seasons, although significant seasonal effects were observed in species richness when the protea cultivars were examined separately. Pesticide application did not affect arthropod abundance, but did decrease species richness in sprayed blocks. Pesticides appeared to negatively affect minor (rare) species disproportionately, probably due to their lack of prior exposure to pesticides and hence sensitivity. Due to this inefficacy of pesticides in cultivated proteas, an increasing emphasis on the importance of non-chemical control measures, and our improved knowledge of the predatory and parasitic species in this system, integrated pest management strategies deserve greater research attention. Monitoring and use of threshold values for arthropod pests were suggested here, as well as the use of biological, cultural, physical and chemical (optimal use) control. For instance, in cultural control, polycropping and intercropping in proteas to increase plant diversity in the monocultures to promote a higher density of predators and parasitoids can be used. Certain flowering plants are known to provide greater temporal and spatial distribution of nectar and pollen sources, which can increase parasitoid reproductive potential and abundance of alternative hosts/prey when the pest species are scarce or at an inappropriate stage. / AFRIKAANSE OPSOMMING: Die kommersiële verbouing van Proteaceae (proteas) is 'n belangrike bedryf in die Wes-Kaap. Menige plantasie wemel egter van artropodes, wat boere noop om slegs van chemiese plaagdoders gebruik te maak. Vorige studies in Suid-Afrika toon dat proteas die gasheerplant vir 'n ryke en diverse artropodefauna is. Aangesien die meeste van hierdie studies egter op wilde proteas uitgevoer is, weerspieël dit moontlik nie die stand van sake met verboude proteas nie. Weens 'n gebrek aan kundigheid om die artropodes te eien word baie van die spesies boonop nooit uitgeken nie. Dié studies voorsien egter 'n nuttige grondlyn vir 'n ondersoek na die artropodes op proteas, veral vir die bestudering van die gilde wat van die protea leef (“the feeding guild”). Hierdie navorsing het ten doel om 'n intensiewe en omvattende opname te maak van die artropodefauna wat oor die tydperk van 'n jaar op kommersieel verboude proteas voorkom. Die opname is meer bepaald ontwerp om die samestelling van die artropodefauna te bestudeer (deur 'n omvattende verwysingsversameling vir plaagbestuurdoeleindes te skep), en om vas te stel of seisoene en plaagbehandelings enige beduidende uitwerking op die artropodefauna het. Oor 'n tydperk van 12 maande is seisoenale monsters van die vrug- en bloeistadia, saadkoppe en blare van hoofsaaklik kommersiële proteas gesoek en ingesamel. Sewe kommersiële proteablokke sowel as 'n blok wilde proteas het as proefpersele gedien, en twee bespuite blokke is gebruik om die doeltreffendheid van plaagdoder te beoordeel. Individuele artropodes is so noukeurig moontlik uitgeken – 37% tot op spesievlak. Volgens 'n spesieakkumulasiekurwe maak seldsame (kleiner) artropodespesies sowat 70% van die artropodes uit wat op verboude proteas voorkom. Die meer as 8 700 individue van meer as 140 spesies en sowat 80 families wat ingesamel en uitgeken is, toon die rykheid en diversiteit van die artropodefauna op verboude proteas. Hierdie artropodes verteenwoordig die volle reeks plantvreterspesies – van blaardelwers en blaarkouers tot blomknopboorders, sapsuiers en saadvreters. Blombesoeker-/vrylewende spesies was die volopste (72%) en mees divers (25%). Buiten plantvreters was daar ook 'n groot aantal roofinsekte en parasitoïede. Baie van die artropodes was inheems, en sommige (7,86%) het boonop plaagstatus, aangesien hulle beduidende skade aan die proteaplant aanrig. [By ongeveer 60% van die Safari Sunset-kultivar (Leucadendron salignum x L. laureolum) is nuwe stamme en blare byvoorbeeld deur die Epichoristodes acerbella (Tortricidae) aangetas.] Capys alphaeus (Lycaenidae) en Phyllocnistis sp. (Phyllocnistidae) blyk spesialisplae te wees wat onderskeidelik hoofsaaklik die Protea cynaroides en die Susarakultivar (Protea magnifica x P. susannae) in die visier het. Artropodegetalle het nie juis tussen seisoene gewissel nie, hoewel 'n afsonderlike ondersoek van die proteakultivars 'n beduidende seisoenale uitwerking op spesierykheid aan die lig gebring het. Eweneens het die toediening van plaagdoder nie die artropodegetalle verminder nie, maar wel spesierykheid op die bespuite blokke verswak. Plaagdoders blyk besonder negatiewe uitwerking op kleiner (seldsame) spesies te hê – waarskynlik omdat dié spesies nie voorheen aan plaagdoders blootgestel was nie, en dus gevoelig is daarvoor. Weens die oënskynlike ondoeltreffendheid van plaagdoders op verboude proteas, verg 'n toenemende klem op die belang van niechemiese beheermaatreëls, 'n behoefte aan meer kennis van die roof- en parasitiese spesies in die stelsel, en die vraag na geïntegreerde plaagbeheerstrategieë, meer navorsing. Die studie moniteer en gebruik drempelwaardes vir artropodeplae, sowel as biologiese, kulturele, fisiese én chemiese (‘optimalegebruik’-) plaagbeheer. Met kulturele beheer kan poli- en interverbouing van proteas byvoorbeeld gebruik word om plantdiversiteit in die monokulture te verbeter, ten einde só 'n hoër digtheid van roofspesies en parasitoïede in die hand te werk. Sekere blomplante bied kenmerkend 'n wyer tyd- en ruimtelike verspreiding van nektar- en stuifmeelbronne, wat parasitoïede se voortplantingsvermoë en die getalle van alternatiewe gashere/prooi kan verbeter wanneer die plaagspesies skaars is of in 'n ontoepaslike stadium verkeer.

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