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The relationship between ants (Hymenoptera: formicidae), vine mealybug (Hemiptera: pseudococcidae) and parasitoids in vineyards of the Western Cape Province, South AfricaMgocheki, Nyembezi 12 1900 (has links)
Thesis (PhD (Conservation Ecology and Entomology))--Stellenbosch University, 2008. / The mutual association between honeydew foraging ants and vine mealybugs in
vineyards is detrimental to the biological control of the vine mealybug Planococcus
ficus (Signoret). This study investigated the relationship between ants, vine mealybugs
and their parasitoids to improve biological control of the vine mealybug. The
investigation was carried out during two consecutive growing seasons (2005-2006 and
2006-2007) in two major wine grape growing areas of the Western Cape Province,
Simondium (two farms) and Breede River Valley (one farm). A presence – absence
cluster sampling system was used on a biweekly basis throughout both growing seasons
from October to February on each of the farms. Additionally, yellow delta traps with
vine mealybug pheromone, were used to catch parasitoids in vineyards. Prior to harvest,
economic damage to grape bunches was assessed using a 0-3 damage rating index.
Three ant species, Anoplolepis steingroeveri (Forel), Crematogaster peringueyi Emery
and Linepithema humile (Mayr) foraged mainly on vine stems during both seasons,
relative to other plant parts. Vine mealybugs of all stages were found on all sampling
dates. Three species of primary parasitoids attacked the vine mealybug, including
Anagyrus sp. near pseudococci (Girault), Coccidoxenoides perminutus (Timberlake)
and Leptomastix dactylopii Howard. Bunch damage was significantly different between
seasons in the Breede River Valley but not in Simondium. There was a negative linear
relationship between ants and parasitoid activity in all vineyards. Spatial Analysis by
Distance IndicEs (SADIE) was used to analyse spatial distribution of ants and
parasitoids and ArcView, with its extension, Spatial Analyst, were used to map the gap,
patch and local association indices where significant association and disassociation
occurred. A significant association was found between C. peringueyi and parasitoids
and L. humile and parasitoids. There was a significant disassociation between L. humile
and C. peringueyi and between A. steingroeveri and C. peringueyi indicating
interspecific hostility.
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Biological and ecological factors contributing to the successful use of entomopathogenic nematodes (Rhabditida: Steinernematidae and Heterorhabditidae) for the control of codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae) under South African conditionsDe Waal, Jeanne Yvonne 12 1900 (has links)
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.
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The sustainable harvesting of non-timber forest products from natural forests in the southern Cape, South Africa : development of harvest systems and management prescriptionsVermeulen, Wessel Johannes 03 1900 (has links)
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.
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Invasive potential of the Peruvian pepper tree (Schinus molle) in South AfricaMidoko Iponga, Donald 03 1900 (has links)
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.
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Exploring meaningful nature experience, connectedness with nature and the revitalization of transformative education for sustainabilityZylstra, 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.
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Development of a Biotope Quality IndexBredenhand, 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.
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Acoustic profiling of the landscapeGrant, 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.
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Management of Acacia species seed banks in the Table Mountain National Park, Cape Peninsula, South AfricaJasson, 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.
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Small mammal communities in the transformed landscapes of the Western Cape lowlands and their role in alien invasion into fynbos remnantsMugabe, 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.
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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.
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