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Native Fusarium species from indigenous fynbos soils of the Western Cape /Bushula, Vuyiswa Sylvia. January 2008 (has links)
Thesis (MSc)--University of Stellenbosch, 2008. / Bibliography. Also available via the Internet.
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The response of biological communities to natural and anthropogenic habitat fragmentation in South Outeniqua Sandstone Fynbos, South AfricaSandberg, Rory Nimmo 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Habitat fragmentation through the loss and modification of natural ecosystems poses a serious threat to biodiversity globally. Mechanisms and ecological implications of fragmentation have been extensively studied, yet new and meaningful insights continue to be produced. The highly diverse and ecologically complex fynbos shrubland communities that occur in the Cape Floristic Region of South Africa are amongst the most threatened by habitat fragmentation by urban, agricultural and silvicultural land uses and to the spread of invasive alien plants. Fynbos vegetation communities are fire-adapted and exploit the post-fire regeneration niche. Natural stochasticity in the fire regime means that these communities are temporally unstable; a factor that allows for the coexistence of such extreme diversity. Few studies have attempted to assess the influence of habitat fragmentation on this stochasticity, or to investigate the response of biological communities to the conditions that result. It is unknown whether this temporal instability will lead to delayed extinctions in fragmented communities, thus generating extinction debt. South Outeniqua Sandstone Fynbos occurs as a unique landscape mosaic of both insular and extensive habitats, suited to study through an island biogeography framework. Vegetation community stability was assessed through the comparison of historic and recent data sets. The responses of local vegetation and avifaunal communities to habitat fragmentation were assessed and compared on the basis of their differing motility. The unique habitat configurations also allowed for the investigation of extinction debt in the local communities and provided an opportunity to assess the influence of the surrounding matrix on species persistence and on connectivity in the artificial fragments. Data were analysed through simple regression analyses, modified Chi-squared tests and through ordination analyses. Ultimately the value of the artificial habitat fragments for the conservation of biological communities was assessed.
Stability was observed in the vegetation species-area relationship for the natural islands and the mainland sites over twenty-two years. Smaller islands were found to receive fewer fires than large islands and the mainland. This consistently over-extended fire-return interval reduces the stochasticity of the local fire regime causing stable yet depauperate vegetation communities to result. Vegetation communities in the artificial fragments were found to hold area-related extinction debt, possibly due to the relatively long-term demographic turnover that typically occurs in fynbos.
Avifaunal communities varied in their response to fragmentation relative to the vegetation. Birds – being motile – were found to be unaffected by isolation distance or surrounding matrix type – their response due more to changes experienced in the vegetation community than to geographic constraints. Fynbos-typical birds responded to the post-fire age of vegetation. Frugivorous birds and the matrix-habitat edge were identified as sources of alien and non-fynbos plant species that colonise the artificial fragments, potentially reducing the quality of these habitats for avifauna. Fragmented communities of South Outeniqua Sandstone Fynbos have the potential to function as biological reserves. This potential can be realised through the implementation of a fire regime that acknowledges the stochasticity required by the vegetation, the frequency required by the vegetation and the avifauna, and the practicality required by surrounding anthropogenic land-uses. / AFRIKAANSE OPSOMMING: Habitat-fragmentering, deur die verlies en verandering van natuurlike ekosisteme, hou 'n ernstige bedreiging in vir biodiversiteit wêreldwyd. Meganismes en ekologiese implikasies van die fragmentering is al breedvoerig bestudeer, maar nuwe en betekenisvolle insigte word voortaan vervaardig. Die hoogs diverse en ekologies komplekse fynbos-struikveld gemeenskappe wat in die Kaapse Floristiese Streek van Suid-Afrika voorkom, word meeste bedreig deur habitat-fragmentering deur verstedeliking, landbou en houtteeltkundige grondgebruike en die verspreiding van indringerplante. Fynbos gemeenskappe is aangepas tot vuur en die uitbuiting van post- vuur herlewing nis. Natuurlike stogastisiteit in die vuur-bedeling beteken dat hierdie gemeenskappe tydelik onstabiel word, 'n faktor wat die mede-bestaan van uiterste diversiteit moontlik maak. Min studies het al die invloed van habitat-fragmentering op hierdie stogastisiteit ondersoek, of die reaksie van biologiese-gemeenskappe tot die voortspruitende omstandighede. Dit is onbekend of die tydelike onstabiliteit sal lei tot vertraagde uitsterwing in gefragmenteerde gemeenskappe, dus genereer uitsterwings-skuld. Suid Outeniqua Sandsteen Fynbos kom as 'n unieke landskap mosaïek van beide die eilande en uitgebreide habitatte voor, geskik om deur 'n eiland biogeografie raamwerk bestudeer te word. Plant-gemeenskappe se stabiliteit is bestudeer deur die vergelyking van historiese en onlangse data stelle. Die reaksies van die plaaslike plantegroei en voëllewe gemeenskappe tot hul habitat is bestudeer en vergelyk op grond van hul verskillende beweeglikheid. Die unieke habitat konfigurasies het ook toegelaat vir die ondersoek van uitsterwings-skuld in die plaaslike gemeenskappe en 'n geleentheid gebied om die invloed van die omliggende habitat-matriks op spesies volharding en op konneksie in die kunsmatige fragmente te bepaal. Die data is ontleed deur middel van eenvoudige regressie analises, aangepasde Chi -kwadraat toetse en deur koördinerings ontledings. Ten einde die waarde van die kunsmatige habitat fragmente vir die bewaring van biologiese gemeenskappe te bepaal.
Stabiliteit in die plantspesies-area verhouding vir die natuurlike eilande en die vasteland van webwerwe oor twee en twintig jaar was waargeneem. Kleiner eilande het minder brande aangeneem as groot eilande en die vasteland. Hierdie herhaalde oor-uitbrei over-extended vuur-interval het die stogastisiteit verminder van die plaaslike vuur-bedeling wat stabiele tog spesie-arme plantegroei gemeenskappe veroorsaak het. Plantegroei gemeenskappe in die kunsmatige fragmente is bevind om spesie- area -verhouding uitsterwings-skuld te bevat, moontlik as gevolg van die relatiewe lang termyn demografiese omset wat tipies voorkom in fynbos. Voëllewe gemeenskappe het gewissel in hul reaksie tot die fragmentering relatief tot die plantegroei. Voëls – weens hul beweeglikheid – blyk om nie beinvloed te word deur isolasie afstand of omliggende habitat-matriks tipe nie - hul reaksie blyk meer asgevolg van veranderinge wat ervaar word in die plantegroei gemeenskap as geografiese beperkinge. Fynbos-tipiese voëls reageer op die post- vuur ouderdom van plantegroei. Vrugte-etende voëls en die habitat-matriks rand is geïdentifiseer as bronne van uitheemse en nie-fynbos plantspesies wat die kunsmatige fragmente koloniseer, wat potensieel die kwaliteit van hierdie habitatte vir voëls verminder.
Gefragmenteerde gemeenskappe van Suid Outeniqua Sandsteen Fynbos het die potensiaal om as biologiese reserwes te funksioneer. Hierdie potensiaal kan verwesenlik word deur die implementering van 'n vuur-bedeling wat erkenning verleen aan die stogastiesiteit vereis deur die plantegroei, die frekwensie wat deur die plantegroei en die voëllewe vereis word , en die praktiese vereistes van die omliggende menslike grondgebruike.
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The ecology of large herbivores native to the coastal lowlands of the fynbos biome in the Western Cape, South Africa /Radloff, Frans Gustav Theodor. January 2008 (has links)
Dissertation (DSc)--University of Stellenbosch, 2008. / Bibliography. Also available vir the Internet.
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Native Fusarium species from indigenous fynbos soils of the Western CapeBushula, Vuyiswa Sylvia 12 1900 (has links)
Thesis (MSc (Microbiology))--Stellenbosch University, 2008. / The genus Fusarium contains members that are phytopathogens of a number of
agricultural commodities causing severe diseases such as wilts and rots. Fusarium
species also secrete mycotoxins that have devastating effects on humans and animals.
The ability of Fusarium species to change their genetic makeup in response to their
immediate environment allows these fungi to exist in diverse habitats. Due to the
ubiquitous nature of Fusarium, it forms part of the fungal communities in both
agricultural and native soils. Fynbos is the major vegetation type of the Cape Floristic
Region (CFR), which is a region that is renowned for its high plant species diversity and
endemism. In this study, the occurrence and distribution of Fusarium species in
indigenous fynbos soils and associated plant debris is investigated. In addition, the
phylogenetic relationships between Fusarium species occurring in this particular habitat
are evaluated.
Fusarium isolates were recovered from soils and associated plant debris, and
identified based on morphological characteristics. The morphological identification of
isolates was confirmed using Polymerase Chain Reaction (PCR) based restriction
fragment length polymorphism (RFLP) analyses of the translation elongation factor 1
alpha (TEF-1α) and internal transcribed spacer (ITS) regions. Furthermore, phylogenetic
relationships between Fusarium species were based on the TEF-1α, ITS and β-tubulin
gene regions.
One-hundred-and-twenty-two (122) Fusarium strains were isolated from the
fynbos soils in the Cape Peninsula area (Western Cape). Based on both morphological
and molecular identification, the most prevalent Fusarium species in the fynbos soils were F. oxysporum Schlecht. emend. Snyd. and Hans., F. solani (Martius) Appel and
Wollenw. emend. Snyd. and Hans., F. equiseti (Corda) Sacc. and an undescribed
Fusarium species. Fusarium oxysporum was the dominant species in fynbos soils and
strains of this species displayed significant genetic variability. Some strains of both
F. oxysporum and F. solani showed close phylogenetic affinities to formae speciales
(strains pathogenic to specific plant hosts) in the phylogenetic analyses. However, no
diseased plants were observed in and within the vicinity of our sampling sites.
In the third chapter, the undescribed Fusarium strains are described as Fusarium
peninsulae prov. nom. Morphologically these strains are characterized by falcate
macroconidia produced from brown sporodochia. The macroconidia are pedicellate,
falcate to curved with hooked apical cells. Also, this fungus produces apedicellate
mesoconidia on polyphialides in the aerial mycelium and forms microconidia sparsely.
Chlamydospores are formed abundantly on aerial mycelium and submerged hyphae. All
these morphological characteristics closely relate this fungus to F. camptoceras species
complex in Fusarium section Arthrosporiella. However, phylogenetic analysis based on
the ITS sequences differentiate these strains from F. camptoceras and other related
species in section Arthrosporiella.
Considering the fact that both as phytopathogens and saprophytic fungi, Fusarium
species secrete a variety of cell wall degrading enzymes such as cellulases and xylanases.
These enzymes allow the fungi to degrade the plant cell wall components to obtain
nutrients. In Fusarium, notably endoxylanases play a role in phytopathogenesis of these
fungi. Endoxylanase enzymes from F. oxysporum f. sp. lycopersici, F. verticillioides and
F. graminearum have been characterized. In this final chapter, the use of the endoxylanase encoding gene, as a molecular marker in phylogenetic analysis was
evaluated using F. graminearum (Fg) clade species as model. Degenerated primers were
designed and the endoxylanase region amplified by PCR, cloned and sequenced. PAUPgenerated
neighbour-joining analysis of the endoxylanase (XYL) region enabled all
species to be distinguished and was as informative as the analysis generated with UTPammonia
ligase (URA), phosphate permase (PHO), reductase (RED) and trichothecene 3-
О-acetyltransferase (TRI101). Furthermore, the results of the phylogenetic analysis of
XYL showed better species resolution in comparison to the analysis of the structural
genes (TEF-1α and histone H3). Overall, the results demonstrated that phylogenetic
analysis of XYL combined with other functional genes (URA, PHO, RED and TRI101)
clearly distinguished between the Fg clade species far better than the analysis of
structural genes (TEF-1α and histone H3).
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Biodiversity in the genus Penicillium from coastal fynbos soil /Visagie, Cobus M. January 2008 (has links)
Thesis (MSc)--University of Stellenbosch, 2008. / Bibliography. Also available via the Internet.
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The role of overstorey proteoid shrubs in maintaining species richness in a southern Cape mountain fynbos community.Vlok, Johannes Hendrik Jacobus. January 1996 (has links)
This study was conducted to determine if, and how, over storey
proteoid shrubs affect the species richness of a southern Cape
mountain fynbos community. Protea eximia, P. lorifolia and P.
repens were the dominant overstorey shrubs in the community
studied.
The percentage canopy cover and density of overstorey protea
shrubs before a fire were regressed against the a-diversity of
understorey species after a fire, for spatial scales ranging
from 1 - 100m². High canopy cover percentages (≥ 50%) and high
densities (≥ 30 plants per 100m²) of overstorey proteas before
a fire enriched the a-diversity levels of understorey species
after a fire. The spatial scale at which α-diversity was
measured affected results. The number of understorey species at
a site, where overstorey proteas were absent for several fire-cycles,
was compared with those where overstorey proteas
persisted. The number of understorey species was least where
the overstorey proteas were lacking for several fire-cycles,
but results also depended on the spatial scale at which α-diversity
was measured. The basal cover percentage and density
of sprouting understorey species of two sites, burned at
several short (6 year) fire-cycles and where overstorey proteas
were lacking, were compared with those of an adjacent site
which was not burned for 28 years and where the overstorey
proteas persisted. Where several short fire-cycles eliminated
the overstorey proteas, the basal cover percentage of
understorey sprouters was approximately 32% higher than where
the overstorey shrubs persisted. The number of understorey
species in dense clumps of understorey sprouters was contrasted
against those on 0.25m² quadrats located in the open and under
burned skeletons of overstorey protease In dense clumps of
sprouters the mean number of understorey species was less than
half of that for quadrats located in the open, or for quadrats
located under the burned protea skeletons. Species specific
competitive interactions amongst overstorey protea and
understorey sprouter species were examined for several pyric
successional stages. Competitive interactions between
overstorey proteas and understorey sprouters were evident in
all pyric successional stages.
Results indicate that the overstorey proteoid shrubs are
important to restrain the competitive ability of understorey
sprouters, to prevent homogeneity in post-fire regeneration
niches and to amplify within-community patchiness of
understorey species, which ultimately enhances the species
richness of fynbos communities. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1996.
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Small mammal communities in the transformed landscapes of the Western Cape Lowlands and their role in alien invasion into Fynbos remnants /Mugabe, James Chapangara. January 2008 (has links)
Thesis (MScConEcol)--University of Stellenbosch, 2008. / Bibliography. Also available via the Internet.
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Seasonal physiological responses in the Cape Rockjumper (Chaetops frenatus): a Fynbos endemic bird shows limited capacity to deal with temperature extremesOswald, Krista Natasha January 2016 (has links)
The Fynbos biome in south-western South Africa is a global biodiversity hotspot vulnerable to climate change. Of the six Fynbos-endemic passerines, Cape Rockjumpers (hereafter Rockjumpers; Chaetops frenatus) are most vulnerable to increases in temperature, with population declines correlated with warming, and low physiological heat thresholds. Rockjumper’s preferred mountain habitat is predicted to decrease as they lack opportunity to move to cooler regions as temperatures warm. As Rockjumpers currently occupy the coldest regions of the Fynbos, I hypothesized their thermal physiology would show cold adaptation at the expense of lowered ability to cope with higher temperatures. I aimed to determine the seasonal 1) maintenance metabolism and cold tolerance, and 2) thermoregulatory responses to high temperatures of Rockjumpers. I measured seasonal maintenance metabolic rate, thermal conductance, and maximum thermogenic capacity. I also measured seasonal resting metabolic rate, evaporative water loss, evaporative cooling efficiency, and body temperature at high air temperatures. In winter, Rockjumpers had higher maximum thermogenic capacity, lower maintenance metabolic rate, and lower thermal conductance. Lower maintenance metabolic rates (and thus, lower metabolic heat production) combined with the decreased thermal conductance, confers substantial energy savings in winter. The increased winter maximum thermogenic capacity of Rockjumpers was expected, although the mean seasonal values fell below those expected for a ~ 50 g bird using a global data set, suggesting Rockjumpers are not especially cold tolerant. I further show that in summer Rockjumpers had higher elevations in resting metabolic rates, evaporative water loss, and body temperature, denoting higher rates of heat production and lower heat thresholds in summer compared to winter. My results suggest that Rockjumpers are best suited for relatively mild Krista Oswald Dissertation Chapter 1: General Introduction temperatures. While I found further support for a physiological basis for declining Rockjumper populations, further studies on other mechanisms Rockjumpers may possess to cope with climate warming (e.g. behavioural adjustments) are needed in order to truly understand their vulnerability to climate change.
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Physiological effects of indigenous arbuscular mycorrhizal associations on the sclerophyll Agathosma betulina (Berg.) PillansCloete, Karen Jacqueline 10 1900 (has links)
Thesis (MSc)--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: The Mountain Fynbos biome, a division of the Cape Floristic Region (CFR), is
home to round-leafed Buchu [Agathosma betulina (Berg.) Pillans], one of South
Africa’s best-known endangered herbal medicinal plants. Agathosma betulina is
renowned as a traditional additive to brandy or tea, which is used for the
treatment of a myriad of ailments. In its natural habitat, A. betulina thrives on
mountain slopes in acid and highly leached gravelly soils, with a low base
saturation and low concentrations of organic matter. To adapt to such adverse
conditions, these plants have formed mutualistic symbioses with arbuscular
mycorrhizal (AM) fungi. In this study, the effect of indigenous AM taxa on the
physiology of A. betulina is investigated. In addition, the AM taxa responsible for
these physiological responses in the plant were identified using morphological
and molecular techniques.
Agathosma betulina was grown under glasshouse conditions in its native
rhizosphere soil containing a mixed population of AM fungi. Control plants,
grown in the absence of AM fungi, were included in the experimentation. In a
time-course study, relative growth rate (RGR), phosphorus (P)-uptake, P
utilization cost, and carbon (C)-economy of the AM symbiosis were calculated.
The data showed that the initial stages of growth were characterized by a
progressive increase in AM colonization. This resulted in an enhanced P-uptake
in relation to non-AM plants once the symbiosis was established. Consequently,
the lower P utilization cost in AM plants indicated that these plants were more efficient in acquiring P than non-AM plants. When colonization levels peaked,
AM plants had consistently higher growth respiration. This indicated that the
symbiosis was resulting in a C-cost to the host plant, characterized by a lower
RGR in AM plants compared to non-AM plants. Arbuscular mycorrhizal
colonization decreased with increasing plant age that coincided with a decline in
P-uptake and growth respiration, along with increases in RGR to a level equal to
non-AM plants. Consequently, the AM benefit was only observed during the
initial stages of growth. In order to identify the AM fungi in planta, morphological
and molecular techniques were employed, which indicated colonization by AM
fungi belonging to the genera Acaulospora and Glomus. Phylogenetic analyses
of a dataset containing aligned 5.8S ribosomal RNA gene sequences from all
families within the Glomeromycota, including sequences obtained during the
study, supported the above mentioned identification. / AFRIKAANSE OPSOMMING: Die Fynbos bergbioom, ‘n onderafdeling van die Kaapse Floristiese Streek,
huisves rondeblaar Boegoe [Agathosma betulina (Berg.) Pillans], een van Suid
Afrika se bekendste bedreigde medisinale plante. Agathosma betulina is bekend
vir sy gebruik as tinktuur vir die behandeling van verskeie kwale. Die plant kom
voor in bergagtige streke, in suur en mineraal-arm grond, met ‘n lae organiese
inhoud. Gevolglik, om aan te pas by hierdie ongunstige kondisies, vorm die
plante simbiotiese assosiasies met blaasagtige, struikvormige mikorrisa (BSM).
In die huidige studie is die effek van hierdie BSM op die fisiologie van A. betulina
ondersoek. Die identiteit van die BSM is ook gevolglik met morfologiese en
molekulêre identifikasie tegnieke bepaal.
Agathosma betulina plante is onder glashuis kondisies in hul natuurlike grond
gekweek, wat ‘n natuurlike populasie van BSM bevat het. Kontroles is ook in die
eksperiment ingesluit en hierdie stel plante is met geen BSM geïnokuleer nie.
Gevolglik is die relatiewe groeitempo, fosfor opname, fosfor verbuikerskoste
asook die koolstof ekonomie van die plante bereken. Die data het getoon dat die
eerste groeifase gekarakteriseer is deur toenames in BSM kolonisasie vlakke.
Dit het tot ‘n hoër fosfor opname in BSM geïnokuleerde plante gelei. Die laer
fosfor verbuikerskoste gedurende hierdie fase het aangedui dat die plante wat
geïnokuleer is met BSM oor beter meganismes beskik het om fosfor uit die grond
te bekom. Toe BSM kolonisasie vlakke gepiek het, was groei respirasie hoër in
BSM geïnokuleerde plante as in die kontroles. Dit het aangedui dat die BSM kolonisasie van plante tot hoër koolstof kostes vir hierdie plante gelei het, wat
weerspieël is in die laer groeitempo van die BSM geïnokuleerde plante. Die
BSM kolonisasie vlakke het gedaal met toenemende ouderdom van hul gasheer
plante, wat gekarakteriseer is deur ‘n laer opname van fosfor en laer groei
respirasie, tesame met ‘n toename in relatiewe groeitempo tot vlakke soortgelyk
aan die van die kontrole plante. Die BSM voordele vir die plant is dus net
gedurende die eerste groeifase waargeneem. Die BSM wat verantwoordelik is
vir hierdie fisiologiese veranderinge is gevolglik geïdentifiseer met behulp van
morfologiese en molekulêre tegnieke en dit is gevind dat BSM wat behoort tot die
genera Acaulospora en Glomus binne hierdie plante voorkom. Filogenetiese
analise gegrond op opgelynde 5.8S ribosomale RNA geen volgordes afkomstig
van al die families binne Glomeromycota asook volgordes gevind in die studie,
het die bogenoemde identifikasie gestaaf.
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Diversity and ecology of ophiostomatoid fungi and arthropods associated with proteaceae infructescencesRoets, Francois 12 1900 (has links)
Thesis (MSc)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: Five new species of ophiostomatoid fungi, colon ising the infructescences of
serotinous Protea species, have recently been discovered in South Africa. Prior
to this, ophostomatoid fungi were thought to be restricted to the Northern
Hemisphere. The discovery of these five species thus extensively expanded the
known geographical range of these fungi, now also to include the Southern
Hemisphere. Since this discovery, few studies have focused on the interesting
ecology of this group, which is uniquely adapted for spore dispersal by
arthropods. Studies focussed on ophiostomatoid fungi provide an unique
opportunity to study inter-organism interactions between fungi, their host plants
and the arthropods responsible for their spore dispersal. Very few similar studies
have been undertaken, particularly in the Fynbos Biome, to which most of our
economically important Protea species are confined. The current study provides
insight into some ecological aspects of these complex interactions.
The seasonal distribution of the ophiostomatoid fungi associated with the
infructescences of members of the Proteaceae was investigated. Definite
seasonal patterns were observed, with peak fungal colonisation occurring during
the wetter winter months. While determining the host specificity of these fungi, a
new Protea host for Ophiostoma splendens was identified, and a new species of
Rhyncomeliola was discovered. All ophiostomatoid species native to Fynbos in
the Stellenbosch region are exclusively associated with the infructescences of
species in the plant genus Protea.
By employing a multiplex Polymerase Chain Reaction (PCR), a set of group
specific primers was developed for the identification of South African Ophiostoma
and Gondwanamyces fungal DNA. This newly developed method was used to
scan arthropods collected from the infructescences of P. repens for the presence
of 0. splendens and G. proteae spores. By using these group-specific primers, three insects possibly responsible for long range dispersal of fungal spores were
identified. Three further insect species, possibly contributing to the short-range
dispersal of ophiostomatoid spores, were also implicated through this method.
All arthropods associated with the fruiting structures of selected members of the
Proteaceae were also investigated. A total of 62 pseudospecies (ca. 7500
individuals), belonging to 45 different arthropod families, were collected.
Proteaceae species with larger fruiting structures housed more arthropod species
and higher numbers of individuals than Proteaceae taxa with smaller fruiting
structures. Some plant species housed similar arthropod communities, while
others housed unique suites of arthropods. Seasonal patterns in arthropod
numbers were observed, and it was found that, in most instances, arthropod
numbers peaked during the autumn and winter months.
Twenty-five fungal taxa were isolated from various Proteaceae arthropods, many
of which are genera known to include Proteaceae pathogenic species.
Ophiostomatoid fungi have a saprophytic relationship with their Protea hosts, and
may deter some of these potentially harmful fungi from colon ising the
infrutescences. Some fungi showed a high degree of specificity towards potential
vectors, while others were found on a diverse range of arthropods.
This study highlights the existence of complex inter-organismal interactions
within the Fynbos Biome, a study area where the interactions between plants,
fungi and insects have been grossly neglected. The few studies that have been
conducted in this field have mostly focussed on a limited number of organisms,
and no wide-scale attempts, such as presented here, have been published. It is
important to obtain a holistic view in any ecological study that focuses on
interactions between different suites of organisms. Ultimately this will aid in the
development of better conservation strategies. This study thus provides a muchneeded
start in studies on multi-organismal interactions in the Fynbos Biome. / AFRIKAANSE OPSOMMING: Vyf nuwe ophiostoma-agtige fungus spesies is onlangs in die vrug-liggame van
Suid Afrikaanse Protea plante ontdek. Voor hierdie ontdekking, was die
algemene opvatting dat ophiostoma-agtige fungi beperk is tot die Noordelike
Halfrond. Die ontdekking van hierdie vyf spesies het dus die bekende
geografiese verspreiding van hierdie tipe fungi vergroot om nou ook die Suidelike
Halfrond in te sluit. Sederdien het min studies gefokus op die interesante
ekologie van hierdie groep, wat aangepas is vir spoorverspreiding deur
geleedpotiges. Studies wat fokus op die ophiostoma-agtige fungi voorsien 'n
unieke geleentheid om die inter-organismiese-interaksies tussen fungi, hul
gasheer plante en die geleedpotiges wat hul spore versprei, te bestudeer. Baie
min soortgelyke studies is al voorheen in die Fynbos Bioom, waar die meeste
van ons ekonomies-belangrike Protea spesies voorkom, onderneem. Die huidige
studie verleen meer inligting oor sommige ekologiese aspekte van hierdie
komplekse interaksies.
Seisoenale verspreidingspatrone van ophiostoma-agtige fungi geassosieer met
die vrug-liggame van lede van die Proteaceae, is ondersoek. Daar is defnitiewe
seisoenale patrone in die aanwesigheid van fungi gevind, met 'n piek in fungi
kolonisasie-getalle gedurende die vogtiger wintermaande. 'n Nuwe Protea
gasheer vir Ophiostoma splendens en 'n nuwe fungus spesie (Rhyncomeliola
sp.), is ontdek. Alle Fynbos ophiostoma-agtige spesies in die Stellenbosch area,
is beperk tot Protea spesies.
'n Multipleks Polimerase Ketting Reaksie is ontwikkel om die spesifieke DNS van
ophiostoma-agtige fungi te herken. Hierdie metode is gebruik om te toets vir die
aanwesigheid van spore van hierdie fungi op die liggame van geleedpotiges
(geassosieerd met P. repens). Hierdeur is drie insekte wat waarskynlik
verantwoordelik is vir die langafstand verspreiding van spore geidentifiseer. Drie verdere insekte wat moontlik verantwoordelik is vir die kortafstand verspreiding
van ophiostoma-agtige fungi is ook aangewys.
Alle geleedpotiges geassosieer met die vrugstrukture van geselekteerde lede
van die Proteaceae is ondersoek. 'n Totaal van 62 pseudo-spesies (omtrent
7500 individue), wat tot 45 families behoort, is versamel. Proteaceae spesies met
groter vrugstrukture het meer geleedpotige spesies en individue gehuisves as
taksa met kleiner vrugstrukture. Sommige plant spesies het soortgelyke
geleedpotige gemeenskappe gehuisves, terwyl unieke groepe geleedpotiges in
ander plante voorgekom het. Alhoewel die geleedpotiges seisonale variasies in
getalle geopenbaar het, het die meeste groepe 'n piek in getalle getoon
gedurende die herfs- en wintermaande.
Vyf-en-twintig fungi taksa is geïsoleer vanaf verskeie Proteaceae geleedpotiges.
Sommige van hierdie is genera wat Proteaceae patogeniese spesies insluit.
Sommige fungi het 'n hoë graad van spesifisiteit teenoor potensiële vektore
getoon, terwyl ander weer algemeen op verskeie geleedpotige spesies gevind is.
Hierdie studie dui op die bestaan van komplekse inter-organismiese-interaksies
in die Fynbos Bioom, in 'n area waar die studie van interaksies tussen plante,
fungi en insekte nog baie min aandag geniet het. Die beperkte aantal studies wat
tot dusver in hierdie veld onderneem is, fokus gewoonlik slegs op 'n paar
organismes. Geen grootskaalse studies, soos die een hier voorgelê, is al
gepubliseer nie. In enige ekologiese studie wat fokus op interaksies tussen
verskeie organismes, is dit belangrik om 'n holistiese siening te probeer verkry.
Uiteindelik sal dit bydra tot die ontwikkeling van beter bewarings-strategië.
Hierdie studie verleen dus 'n noodsaaklike begin tot studies op multiorganismiese-
interaksies.
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