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Springtail diversity in the Cape floristic regionJanion, Charlene, Scheepers, Charlene 03 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Understanding the distribution, abundance and diversity of species and the mechanisms
causing these patterns has been the interest of ecologists and taxonomists for decades. The
exceptionally high plant diversity in the Fynbos biome has been well studied. Whilst early
arguments suggested that the high plant diversity is not reflected in the arthropod diversity
and that insect species richness is low compared to other comparable areas, these
observations might have been hampered by the taxonomic impediment. Despite global
recognition of the significance of this below-ground component of diversity for ecosystem
functioning, soil is one of the most poorly studied habitats of terrestrial ecosystems.
Although knowledge is increasing for epigaeic groups, other significant groups such as the
Collembola remain especially poorly understood. This thesis starts addressing this serious
gap in knowledge concerning the below-ground component of biodiversity in the Fynbos
biome and the effects of landscape transformation thereon. As part of the work,
considerable attention was given to resolving the taxonomic impediment for the springtail
fauna of the Fynbos biome using modern morphological and DNA barcoding methods, while
also examining the correlates of soil animal diversity in the biome, by using Collembola
(springtails) as exemplars. First, using a combination of published records of Collembola
from South Africa, various sampling methods and DNA barcoding, a species list is compiled
for the Western Cape. Currently 213 species are known to exist from the Western Cape. A
high level of cryptic diversity was also found in several genera, together with several
potential species radiations in the Ectonura, Seira, Parisotoma and Cryptopygus. A start is a
made at addressing the lack of taxonomic knowledge by describing five new species. Two
Ectonura Cassagnau 1980 species are described from Betty’s Bay and Grootvadersbosch
respectively and a key to the Neanurinae of South Africa is provided. The first record of the
genus Triacanthella Schäffer, 1897 is described from a cave in Table Mountain, while two
new species of Delamarephorura are described and the genera Spicatella Thibaud 2002 and
Delamarephorura Weiner & Najt 1999 are synonymized. Although fire is thought to be the
main form of decomposition in the Fynbos biome, recent work has shown that biological
decomposition may be more important than previously thought. I examine the resilience of
Collembola after a large-scale fire in Jonkershoek Nature Reserve using quantitative
sampling which is temporally replicated. The resilience of invertebrate fauna in the fynbos is
not well understood, thus I investigate the diversity of Collembola before and after a major
fire. Results show Collembola species richness and abundance recovered surprisingly quickly after the fire. On a larger scale, litterbags were deployed at six sites across the Western Cape
using different litter types. Here, a total of 113 morphospecies species was found. Local
richness was found to be highest in Kogelberg (32 species), while the turnover between sites
was also high. Thus, the degradation of local habitat patches will be as much of a threat to
Collembola as to the endemic plants in this region. / AFRIKAANSE OPSOMMING: Begrip van die verspreiding, spesierykheid en verskeidenheid van spesies en die meganismes
wat hierdie patrone veroorsaak is al die belangstelling van ekoloë en taksonome vir dekades.
Die buitengewoon hoë plant diversiteit in die Fynbos-bioom is goed bestudeer. Terwyl vroeë
argumente voorstel dat die hoë plantdiversiteit nie weerspieël word in die geleedpotige
diversiteit nie en dat insekspesierykheid laag is in vergelyking met ander gebiede, kon
hierdie waarnemings nie gemaak word nie as gevolg van taksonomiese hindernisse. Ten
spyte van die wêreldwye erkenning van die belangrikheid van hierdie ondergrondse
komponent van diversiteit vir die funksionering van die ekosisteem, is die grond een van die
swakste bestudeerde habitatte van terrestriële ekosisteme. Alhoewel kennis vermeerder vir
bogrondse groepe, word ander belangrike groepe soos die Collembola swak verstaan.
Hierdie tesis begin hierdie ernstige leemte in kennis aanspreek, met betrekking tot die
ondergrondse komponent van biodiversiteit in die Fynbos bioom en die gevolge van die
landskap transformasie daarop. As deel van die werk, is heelwat aandag gegee aan die
oplossing van die taksonomiese hindernis vir die springstert fauna van die fynbos bioom met
behulp van moderne morfologiese en DNA metodes, terwyl dit ook die ooreenkomste van
grond diere diversiteit ondersoek in die bioom, deur gebruik te maak van Collembola
(springsterte) as voorbeelde. Eerste, met behulp van 'n kombinasie van gepubliseerde
rekords van Collembola van Suid-Afrika, verskillende kolleksie metodes en DNA metodes is 'n
spesielys saamgestel vir die Wes-Kaap. Tans is 213 spesies bekend vir die Wes-Kaap. 'n Hoë
vlak van kriptiese diversiteit is ook gevind in verskeie genera, saam met verskeie potensiële
spesies radiasies in die Ectonura, Seira, Parisotoma en Cryptopygus. 'n Begin is gemaak op
die aanspreek van die gebrek van taksonomiese kennis deur vyf nuwe spesies te beskryf.
Twee Ectonura Cassagnau 1980 spesies van Bettiesbaai en Grootvadersbosch is beskryf en 'n
sleutel tot die Neanurinae van Suid-Afrika word verskaf. Die eerste rekord van die genus
Triacanthella Schaffer, 1897 word beskryf van 'n grot in Tafelberg, terwyl twee nuwe spesies
van Delamarephorura beskryf word en die genera Spicatella Thibaud 2002 en Delamarephorura Weiner & Najt 1999 gesinomiseer word. Hoewel vuur beskou word as die
belangrikste vorm van ontbinding in die Fynbos bioom, het onlangse werk getoon dat die
biologiese ontbinding belangriker mag wees as wat voorheen vermoed was. Ek ondersoek
die veerkragtigheid van Collembola na 'n groot skaal vuur in Jonkershoek Natuurreservaat
met behulp van kwantitatiewe steekproefneming wat tydelik herhaal. Die veerkragtigheid
van ongewerwelde fauna in die fynbos word nie goed verstaan nie, dus het ek ondersoek
ingestel na die diversiteit van Collembola voor en na 'n groot vuur. Resultate toon dat
Collembola se spesierykheid en hoveelheid verbasend vinnig herstel na die vuur. Op 'n
groter skaal, is kolleksies by ses plekke regoor die Wes-Kaap gebruik en verskillende
blaarafval word vergelyk. Hier word 'n totaal van 113 morfologiese spesies gevind. Daar is
gevind dat die hoogste aantal spesies in Kogelberg is (32 spesies), terwyl die omset tussen
plekke baie hoog was. So sal die agteruitgang van plaaslike habitatte net soveel van 'n
bedreiging inhou vir Collembola as vir die endemiese plante in hierdie streek.
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Water regime requirements and possible climate change effects on Fynbos Biome RestionaceaeAyuk, James January 2018 (has links)
Philosophiae Doctor - PhD / The Cape Floristic Region (CFR) of southern Africa is one of the world’s most unique
biodiversity hotspots. However, this biodiversity continues to be threatened by habitat loss
due to rapid urbanisation, agriculture and alien vegetation encroachment, and now, by future
groundwater extraction and climate change. Previous work had shown that soil moisture is
important in structuring wetland plant communities at fine-scale. What is not fully known,
however, is how the spatial distribution of species at a local scale is related to soil hydrology
and what the response in the future of species distributions will be to perturbations arising
from changes in climate or subsurface moisture in the future. The current research
investigated the water regime of the Restionaceae which is a key family in the Fynbos biome
and the implications of possible changes in soil hydrology caused by climate change in
communities within this region. The Restionaceae were particularly appropriate because
they are shallow rooted perennials with the ability to tolerate a wide range of water regimes
which allows them to successfully co-habit within mixed plant communities as segregated
clusters along fine-scale hydrologic gradients. Vegetation survey counts for the presence of
these species along with measurements of soil water table depth and moisture content data
generated from eight small-scale plots (50 x 50 m) were used to investigate the possible
hydrological niches and to envision the potential impacts of a substantial reduction in rainfall
and an increase in temperature as projected by Global Climate Models (GCMs) on the
structure of Restionaceae communities in seasonal wetlands by 2100. A comparative
analysis of the effects of two extreme Representative Concentration emission Pathways
(RCP2.6 and RCP8.5) on significant hydrological variables to plant water regimes was
carried out. The IPCC AR5 report describes the RCP8.5 emissions scenario as the likely
‘business as usual’ scenario where emissions continue to rise through the 21st century while
the RCP2.6 scenario assumes that emissions peak between 2010 and 2020 and
substantially subside thereafter.
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Reassessment of species limits and diversification process in the Cape grass genus Ehrharta ThunbWootton, Lara 29 January 2021 (has links)
The Greater Cape Floristic Region (GCFR) of South Africa has one of the most biodiverse floras in the world. Although ecological speciation is thought to be a primary mechanism behind diversification in the GCFR, it has recently been hypothesised that non-ecological speciation may have an influential role in driving diversification in the montane “sky islands” of the GCFR, potentially resulting in cryptic species. This work seeks to test the relative importance of ecological versus non-ecological processes in powering speciation at different elevations in the GCFR, and to assess the existence of multiple, range-restricted cryptic species at high elevations. The Cape grass genus Ehrharta is an ideal system in which to investigate these processes, as it contains low-, mid-, and high-elevation lineages, with a previously documented adaptive radiation in the succulent karoo. Population-level phylogenetic analyses using targeted enrichment sequencing data show that E. rupestris and E. setacea, as currently defined, are polyphyletic, and reveal multiple distinct monophyletic lineages within the Ramosa, Rehmannii and Setacea clades of genus Ehrharta. Analysis of genotyping-by-sequencing and morphological data, together with evidence of sympatry, confirm these lineages to be distinct entities, resulting in 13 to 16 putative new species, of which several can be considered cryptic. The crown node of Ehrharta is found to have originated 28 Ma, which substantially antedates previous age estimates. Comparisons of morphological evolutionary rates, as well as rates of nonsynonymous to synonymous sequence evolution (��), provide little evidence to support the hypothesis that non-ecological processes have been more important at high elevations. Both the low- and high-elevation clades show evidence of divergent ecological selection, with the Lowlands clade exhibiting high functional trait variance, and the high-elevation Setacea clade showing subtle ecological differentiation and accelerated rates of morphological evolution and �� relative to the rest of Cape Ehrharta. It is instead suggested that diversification in the Cape Ehrharta is triggered by a combination of intrinsic and extrinsic factors unique to each clade, thus corroborating a growing body of research arguing that it is simplistic to generalise radiations as ‘adaptive’ or ‘non-adaptive’. Instead, mountain radiations require an integrated approach to untangle the subtle interaction of geographic, ecological and biological factors that drive diversification.
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Chemical investigation of some species of Amaryllidaceae from the Greater Cape Region of South Africa as a source of bioactive compoundsIbrakaw, Abobaker Saleh Mohamed January 2020 (has links)
Philosophiae Doctor - PhD / The family Amaryllidaceae is widely distributed in the southern hemisphere. Members of the family are well known for their content of pharmacologically active alkaloids and represent an important epicentre of Amaryllidaceae-alkaloid diversity. Other metabolites from Amaryllidaceae, such as phenolics including flavonoids, lignans, chromones, and acetophenones, in addition to terpenoids and ceramides have been reported. Boophone haemanthoides (BHE), Crossyne flava (CRO), Clivia miniata (CME) and Nerine humilis (NHE) are members of Amaryllidaceae that have shown biological activity. Parkinson’s disease (PD) is a neurodegenerative disease that progresses with increasing age and some of its major symptoms include tremors, postural and movement related difficulties. To date, the treatment of PD remains a challenge because available drugs only treat the symptoms of the disease or possess serious side effects. In light of this, new treatment options are needed, hence this study investigates the neuroprotective effects of BHE and CRO along with the isolated compounds of BHE and CRO. / 2022
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The effects of phosphorus (P) deficiency on growth and nitrogen fixation of Virgilia trees from the Cape Floristic Region (CFR)Magadlela, Anathi 03 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The aim of this study was to determine how P nutrition affects biological nitrogen fixation (BNF) via effects on the N2-fixing bacteria in the nodules of Virgilia species native to the Cape Floristic Region (CFR), South Africa. This was evaluated in 3 separate studies:
The first study aimed to determine how phosphorus deficiency affects N nutrition of two legume tree species from the Mediterranean Fynbos ecosystem. This study showed that during prolonged P deficiency, V. divaricata maintained a constant biomass, while V. oroboides showed a decreased biomass. V. oroboides showed a decrease in nutritional concentrations, which resulted in the decrease of symbiotic nitrogen fixation (SNF). Both plants utilized atmospheric N more efficiently per nodule under P deficiency. Maximum photosynthesis decreased in V. oroboides, while V. divaricata maintained its photosynthesis. Both species also had greater carbon construction costs during P deficiency. V. divaricata showed clear adaptive features during P-deficiency, as it maintained its growth respiration. The two legume species appear to have different adaptations to P deficiency, which may influence their performance and distribution in their naturally low P environment. The second study aimed to evaluate if soil environmental conditions and mineral nutrient concentration play a major role in microbial communities in plant rhizosphere and nodulation during N2 fixation in legumes. Therefore this study firstly aimed to determine the composition of the N2 fixing bacterial population in the rhizosphere and nodules of V. divaricata. Secondly, it aimed to determine the contribution of these bacteria to N2 fixation during conditions of P deficiency in the Fynbos environment. In the study, the effects of phosphate (P) nutrition on N2 fixing bacterial community structures in Virgilia divaricata rhizosphere and nodules were examined in a pot experiment. V. divaricata were germinated in Fynbos soil as natural inoculum, transferred to clean sand cultures and supplied with 500 μM P and 5 μM P. The N2 fixing bacterial communities in the rhizosphere and nodules were examined based on the PCR-DGGE banding patterns of 16S rDNA and sequencing methods. The GenBank blast results revealed that V divaricata was efficiently nodulated by a wide range of root-nodule bacterial strains, including Burkholderia phytofirmans, Burkholderia sp. and Bradyrhizobium sp. during low P supply. The 15N natural abundance data also confirmed that 40-50% of the N nutrition was acquired through symbiotic N2 fixation. This is not only evidence of nodulation, but also an indication of the adaptation of a range of N2 fixing bacterial strains / species to the nutrient poor, sandy, acidic soil of the Mediterranean-type ecosystems of the Fynbos.
The third study examined the physiological effects, such as N2 fixation parameters, plant dependence on N2 fixation, N preference, legume plant growth, carbon costs and amino acid biosynthesis during P deficiency and mineral N supply as NH4NO3 in a slow-growing, Fynbos legume tree, Virgilia divaricata. Continued application of NH4NO3 to the legume plant showed a greater increase in plant dry matter compared to plants with two nitrogen sources (mineral N and atmospheric N2) or plants that relied on atmospheric N2 fixation. Carbon construction costs were more pronounced in plants supplied with two N sources and during P deficiency. Maximum photosynthetic rates per leaf area increased during prolonged P deficiency, irrespective of the N sources. Though plants nodulated, plant dependence on N2 fixation decreased with the addition of NH4NO3. Roots and nodules of the P deficient plants showed an increase in asparagine content, most strikingly so in plants treated with a single source of N. These studies reveal that different legume species of the same genus, may employ contrasting adaptations in order to maintain N nutrition under P deficiency. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie was die bepaling van die wyse waarop fosfaat (P) voeding die biologiese stikstof binding (BNF) deur middel van die effek op N2-bindingsbakterië in die wortelknoppies van Virgilia spesies wat inheems tot die Kaap floraryke area (CFR), Suid Afrika is, affekteer. Drie aparte eksperimente is uitgevoer om die doel te evalueer:
Die eerste studie het gepoog om te bepaal hoe 'n fosfaat tekort N voeding van twee peulplant spesies van die Mediterreense Fynbos ekosisteem affekteer. Hierdie studie het getoon dat V. divaricata 'n konstante biomassa tydens verlengde P tekort behou, terwyl V. oroboides ‟n verlaagde biomassa getoon het. V. oroboides het 'n verlaging in voedingskonsentrasies getoon, wat tot 'n verlaging in simbiotiese stikstof binding (SNF) gelei het. Beide plante benut atmosferiese N meer doeltreffend per nodule tydens P tekort. Die maksimum fotosintese in V. oroboides het afgeneem, terwyl V. divaricata sy fotosintese gehandhaaf het. Beide spesies het ook 'n groter koolstof konstruksie koste tydens P tekort gehad. V. divaricata toon duidelike aanpassingsmeganismes tydens P-tekort, aangesien hierdie species sy groei respirasie konhandhaaf. Dit wil voorkom asof die twee peulplant spesies verskillend aangepas is vir P tekort, wat hulle producksie en verspreiding in hulle natuurlike lae P omgewing mag beïnvloed. Die doel van die tweede studie was om te bepaal of grond omgewingskondisies en minerale voedingskonsentrasie 'n belangrike rol speel in die mikrobiese gemeenskappe in die plant risofeer en wortelknoppie vorming tydens N2 binding in peulgewasse. Eerstens het die studie dus gepoog om die samestelling van die N2 bindende bakteriële populasie in die risosfeer en die wortelknoppies van V. divaricata te bepaal. Ten tweede, is die bydrae van die bakterië tot N2-binding tydens P tekort kondisies in die Fynbos omgewing bepaal. In die studie is die effek van fosfaat (P) voeding op die N2-bindende bakteriële gemeenskapstrukture in die Virgilia divaricata risofeer en wortelknoppies in 'n pot eksperiment ondersoek. V. divaricata sade is in fynbos grond as 'n natuurlike inokulum ontkiem, waarna dit na skoon sand kulture oorgedra is en van 500 μM P en 5 μM P voorsien is. Die N2-bindende bakteriële gemeenskappe in die risofeer en wortelknoppies is op grond van die PCR-DGGE band patrone van die 16S rDNA en volgorde bepalingsmetodes ondersoek. Die GenBank Blast resultate het getoon dat V. divaricata doeltreffend deur 'n wye reeks wortel-wortelknoppie bakteriële stamme genoduleer is, insluitende insluitende Burkholderia phytofirmans, Burkholderia sp. en Bradyrhizobium sp. tydens lae P toediening. Die natuurlike 15N voorkoms data het ook bevestig dat 40-50% van die N voeding deur simbiotiese N2 binding bekom is. Dit dien nie net as bewys vir wortelknoppie vorming nie, maar ook 'n aanduiding van die aanpassing van 'n reeks N2 bindende bakteriële stamme/ spesies tot die voedingsarme, sanderige, suur grond van die Mediterreanse ekosisteem van die Fynbos.
Die derde studie het die fisiologiese effekte soos bv. N2 fikserings faktore, die afhanklikheid van plante op N2 fiksering, N voorkeur, peulgewas groei, koolstof kostes en aminosuur biosintese tydens P tekort en minerale N toediening soos NH4NO3 in 'n stadig-groeiende, Fynbos peulgewasboom, Virgilia divaricata ondersoek. Volgehoue toediening van NH4NO3 aan die peulplant toon 'n groter toename in plant droë weefsel. Tydens P tekort is die koolstof bou koste meer verhoog in plante wat met twee N bronne voorsien is. Tydens verlengde P tekort het die maksimum fotosintese tempo per blaaroppervlakte toegeneem, ongeag die N bron. Alhoewel die plante wortelknoppies gevorm het, het die plant se afhanklikheid van N2 binding tydens die toediening van NH4NO3 afgeneem. Wortels en wortelknoppies van die P tekort plante het 'n toename in asparagien inhoud getoon, veral in die plante wat met 'n enkele bron van N behandel is. / The DST/NRF-Center of Excellence for Tree Health and Biotechnology, based at the University of Pretoria, for their financial support
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Untangling mechanisms structuring insect diversity patterns in the Cape Floristic Region : the Restionaceae and their herbivoresKemp, Jurene Ellen 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Research into the patterns and drivers of insect diversity in the Cape Floristic Region (CFR)
lags far behind that of plants. Here I sample insect herbivore communities on a dominant
plant family (Restionaceae), and use a spatially nested sampling design and network analysis
to evaluate the association between plant and insect diversity in the CFR. I find that plant
species richness predicts insect richness better than environmental factors. Turnover in insect
communities is strongly associated with turnover in plant (both species and phylogenetic)
communities at both local and regional sampling scales, suggesting insect host specificity.
Plant communities unsurprisingly show significant turnover at small spatial scales (i.e.
communities situated 0.1-3 km apart show significant turnover and may be tied to ecological
niches). Insects show a similar pattern, but the decrease in community overlap is more
gradual, suggesting many insects can utilise multiple (possibly closely related) hosts while
plants are tied to particular niches. The emergent structure of multiple interaction networks is
spatially and temporally invariant, despite high compositional change. However, the internal
structure of the networks shows variation (i.e. interactions show spatial and temporal
turnover). Seasonal interaction turnover is driven by a turnover in herbivores and by
herbivore host switching. Spatially the turnover in interactions is driven by simultaneous
turnover in both plants and insects, either suggesting that insects are host specific, or that
both groups exhibit parallel responses to environmental gradients. Spatial interaction turnover
is also driven by a turnover in plants, showing that many insects can utilise multiple (possibly
closely related) hosts and have wider distribution ranges than their host plants. Results point
toward insect host specificity, but probably not at the species level, as the primary mechanism
structuring insect communities associated with the Restionaceae in the CFR. / AFRIKAANSE OPSOMMING: Navorsing wat verband hou met die patrone en meganismes wat insekdiversiteit in the
Kaapse Blommeryk (KBR) hou nie pas met dié van plante nie. In hierdie studie neem ek
insekmonsters binne een van die dominante plantfamilies (Restionaceae), en gebruik ‘n
ruimtelik geneste ontwerp en netwerkanalise om die verbintenis tussen plant- en
insekdiversiteit te evalueer. Ek vind plantrykheid voorspel insekrykheid beter as enige
omgewingsfaktore. ‘n Omset in in insekgemeenskappe is sterk verbind aan ‘n omset in
plantgemeenskappe (beide spesie en filogenetiese) by beide plaaslik en vir die hele streek.
Hierdie dui op insekgasheerspesifisiteit. Plantgemeenskappe wys omset teen kort ruimtelike
skale (0.1-3 km). Insekte wys ‘n soortgelyke patron, maar die afname in oorvleueling tussen
gemeenskappe is meer geredelik. Dit dui dat insek meer as een gasheer kan gebruik, terwyl
plante streng tot sekere nisse verbind is. Die ontluikende struktuur van menigde
interaksienetwerke wys geen ruimtelike of tydelike variasie nie, ten spyte van hoë
gemeenskapsomset. Nietewel, die interne struktuur van die netwerke wys veranderinge
(interaksies in netwerke wys omset). Seisonale interaksie-omset kan toegeskryf word aan ‘n
omset van herbivore en insekgasheerverandering. Ruimtelike interaksie-omset word
toegeskryf aan gelyktydige insek- en plantomset, wat óf deur insekgasheerspesifisiteit
veroorsaak word óf deur parallele reaksies tot omgewingsveranderinge. Ruimtelike
interaksie-omset word ook deur plantomset beïnvloed, wat aandui sommige insekte kan meer
as een gasheer benut en insekte het weier verspreidings as hul gasheer. Resultate dui daarop
dat insekgasheerspesifisiteit, maar waarskynlik nie op die spesievlak nie, moontlik die
primêre meganisme is wat insekgemeenskappe verbind aan die Restionaceae in die KBR
struktureer.
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A study of tristyly in South African oxalisTurketti, Sandy Siqueira 12 1900 (has links)
Thesis (PhD (Botany and Zoology))--University of Stellenbosch, 2010.
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Assembly and disassembly of bird pollination communities at the Cape of AfricaGeerts, Sjirk 03 1900 (has links)
Thesis (PhD (Botany and Zoology))--Stellenbosch University, 2011. / ENGLISH ABSTRACT: With the current global decline in pollinators, and the concurrent decline in plant species, pollination research is becoming increasingly important. However, studies outside Europe and North-America and on groups other than insects are needed to make generalisations possible. In this thesis I study how pollination structures plant and bird communities in a biodiversity hotspot, the Cape Floristic Region of South Africa. I show that bird-plant pollination mutualisms are an important ecological factor structuring ornithophilous Proteaceae and nectar-feeding bird communities. This close association between plant and bird communities suggests an important role for community wide pollination mutualisms.
How these mutualisms disassemble in reaction to a range of anthropogenic impacts is determined. Firstly, I use experimental manipulation of honeybee density to test whether honeybee farming affects nectar-feeding birds. Hive addition increased honeybee abundance far above natural levels but nectar-feeding bird pollinators were not consistently affected. Secondly, I document the impact of a two lane tar road on the bird pollination community. The two-fold decline found in pollination along roadsides, should have important implications for the way we view and manage road verges for ecological processes. Thirdly, I investigated how fragmentation affects bird-pollination communities by assessing an endangered, bird-pollinated plant, Brunsvigia litoralis. The only flower visitor at the urban sites, the shorter billed Greater Double-collared Sunbird is unable to access the nectar due to a long perianth tube. The longer billed Malachite Sunbird was the sole pollinator of B. litoralis at the rural site, significantly increased seed set. The lack of ecological analogs in these urban fragments might place pollinator specialist plants, such as B. litoralis, at risk. Fourthly, fire is a frequent disturbance in communities of bird-pollinated plants. In a before/after fire observation study and a burnt/unburnt transplant study, birds visited flowers in the “before fire” and “unburnt” areas only. The results are surprising given the large number of bird-pollinated plants flowering in the early post-fire vegetation. Lastly, I find that alien invasive plant species are incorporated into the native pollination community in a spectacular way; sunbirds adapt to a hummingbird-like, hovering lifestyle to obtain nectar. Alien invasive plants greatly increase nectar-feeding bird abundance; in turn, birds enhance seed set in these alien plants.
I conclude by asking whether the disassembling of bird pollination communities really matters. To answer this question I report on a decade of demographic data on the geophytic bird-pollinated Brunsvigia orientalis. In the demographic analysis, the elasticity component for reproduction was more important than expected for a long lived plant. Reduced population growth in the shade and a large investment in a winged inflorescence, suggest B. orientalis is a light demanding, well dispersed, gap colonising species. The link between pollination and seed has been made before, but I take this one step further and show that pollination intensity predicts population growth rate. By linking plant demography and pollination, I was able to predict the future of plant populations under variable pollination conditions. The disassembly of bird pollination communities only becomes important for population persistence once the mutualism has almost entirely broken down. / AFRIKAANSE OPSOMMING: Met die huidige globale afname in bestuiwers en die gelyktydige afname in plant spesies, word bestuiwing navorsing toenemend belangrik. Studies buite Europa en Noord-Amerika en op groepe anders dan insekte is nodig on veralgemenings moontlik te maak. In hierdie tesis bestudeer ek hoe bestuiwing struktuur gee and plant en voël gemeenskappe in 'n biodiversiteit hotspot, die Kaapse Floristiese Ryk van Suid-Afrika. Ek wys dat voël-plant bestuiwings mutualismes 'n belangrike ekologiese faktor is in die strukturering van voël bestuifde Proteaceae gemeenskappe en nektar-etende voël gemeenskappe. Hierdie noue assosiasie tussen plant en voël gemeenskappe impliseer 'n belangrike rol vir gemeenskapwye bestuiwings meganismes.
Ek bepaal hoe hierdie mutualismes aftakel in reaksie op 'n verskeidenheid van antropogeniese impakte. Eerstens gebruik ek 'n eksperimentele manipulasie van heuningby getalle om te toets of bye boerdery nektar-etende voëls affekteer. Byekorf toevoeging het heuningby getalle laat toeneem tot ver bo natuurlike vlakke maar nektar-etende voël bestuiwers is nie konsekwent beïnvloed nie. Tweedens dokumenteer ek die impakte van 'n twee baan teerpad op die voël bestuiwings gemeenskap. Die twee-malige afname in bestuiwing langs paaie sal belangrike implikasies hê vir die manier hoe ons pad reserwes sien en bestuur met betrekking tot ekologiese prosesse. Derdens bestudeer ek hoe fragmentasie die voël-plant gemeenskappe affekteer deur die bedreigde voël-bestuifde Brunsvigia litoralis te assesseer. Die enigste besoeker in die meer stedelike area, die Groot-rooibandsuikerbekkie, wat 'n korter snawel het, is nie in staat om die nektar te bereik nie, weens 'n te lang blombuis. Die Jangroentjie suikerbekkie met sy langer snawel is die enigste bestuiwer van B. litoralis in die meer landelike area, met 'n betekenisvolle vermeerdering in saad vorming. Die gebrek aan ekologies analogiese spesies in die stedelike fragmente kan 'n risiko inhou vir bestuiwer gespesialiseerde plante soos B. litoralis. Vierdens, vuur is 'n gereelde versteuring van voël-plant gemeenskappe. In 'n voor/na vuur observasie studie en 'n brand/nie-brand verplasing studie, het voëls blomme net in die “voor brand” en “nie-brand” areas besoek. Hierdie resultate is verrassend siende die groot hoeveelheid voël-bestuifde plante wat blom direk na brande. Laastens het ek gevind dat uitheemse indringer plante geïnkorporeer word in die inheemse bestuiwers gemeenskappe op 'n skouspelagtige manier; suikerbekkies pas aan tot 'n kolibri-tipe, fladderende lewenswyse om nektar te bekom. Uitheemse indringer plante het nektar-etende voël hoeveelhede laat toeneem; in reaksie het voëls saad opbrengs vermeerder. In konklusie vra ek of hierdie aftakeling van die voël bestuiwers gemeenskap belangrik is. Om hierdie vraag te antwoord assesseer ek 'n dekade van demografiese data van die geofietiese, voël-bestuifde plant, Brunsvigia orientalis. In die demografiese analises was die elastisiteit komponent van reproduksie belangriker as verwag vir 'n langlewende plant. Verminderde populasie groei in die skaduwee en 'n hoë investering in 'n gevlerkte bloeiwyse suggereer dat B. orientalis 'n lig afhanklike, goed verspreide, gaping koloniserende spesie is. Die skakel tussen bestuiwing en saadvorming is voorheen gemaak, maar ek neem dit een stap verder en wys dat bestuiwings intensiteit populasie groeikoers voorspel. Deur plant demografie en bestuiwing te koppel was ek in staat om die toekoms van populasies onder variërende bestuiwings kondisies te voorspel. Die aftakeling van voël bestuiwings gemeenskappe word slegs belangrik vir populasies se voortbestaan wanneer die mutualisme amper heeltemal verdwyn het.
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The regulation of Phosphoenolpyruvate (PEP) metabolism via Phosphoenolpyruvate Carboxylase (PEPC) in P-deficient roots and nodules of Virgilia divaricataStevens, Gary 12 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Plants exhibit a flexible array of morphological, physiological and biochemical adaptations during
phosphorous limitation. Legumes are vulnerable to P deficiency, because it affects their ability to
fix atmospheric nitrogen (N2). In particular, legumes from nutrient-poor ecosystems, such as the
Fynbos in the Cape Floristic Region (CFR) evolved on P deficient soils and may therefore display
unique adaptations to soil P stress. In general, very few studies on legumes have focussed on the
belowground structures of nodules as a plant organ. Moreover, even less is known about the P
stressed responses in nodules from legumes in nutrient-poor ecosystems. The aim of this research
was to investigate the metabolic flexibility of organic acid and amino acid metabolism in the
nodulated root system of the Fynbos legume Virgilia divaricata, during low P stress.
Virgilia divaricata, which grows in the Cape Floristic Region, was used in this study to enhance
our knowledge regarding the vital role that the cytosolic enzyme, phosphoenol pyruvate
carboxylase (PEPC) plays in phosphoenol pyruvate (PEP) metabolism, in roots and nodules of this
legume during phosphate stress. V. divaricata was grown under glasshouse conditions (20 - 25°C)
in sterilized quartz sand for 2-3 months whilst being inoculated with the nitrogen fixation bacteria,
Burkholderia phytofirmans, which was isolated from V. divaricata nodules grown in fynbos soil.
Two phosphate treatments, 5 μM and 500 μM, were applied simulating low-phosphate and high
phosphate conditions respectively using a modified Long Ashton Nutrient Solution to simulate a
low nutrient ecosystem such as the Cape Floristic Region. Roots and nodules were then analysed
for growth kinetics, nutrient acquisition and distribution, enzyme activity and genetic responses. It
was shown that during phosphate deficiency, V. divaricata nodules experienced less Pi stress than
roots, due to increased metabolic phosphate conservation reactions during organic acid synthesis
via an increased PEPC activity. The increased PEPC activity resulted in an increase in downstream
metabolic products such as organic acids, (malic acid and citric acid), and amino acids (glutamate,
aspartate and asparagine). Although the biological nitrogen fixation (BNF) declined, the high
efficiency of BNF may be underpinned by these altered phosphate conservation pathways and
enhanced resource allocation during growth particularly under low phosphate (LP) conditions. Therefore, it can be concluded that the efficiency of the nodules via an increased allocation of
resources and P acquiring mechanisms in V. divaricata may be the key to the plant’s ability to
adapt to poor P environments and thus sustaining its reliance on BNF. From the data obtained as
well as previous findings, it has been established that the phosphate conservation mechanisms in roots and nodules, involve the non-adenylate requiring PEPC-bypass route. 13C Nuclear magnetic
resonance (NMR) gave us a better understanding regarding the incorporation rates of the PEPCderived
C into malate, α-ketoglutarate and asparagine. It therefore is suggested that V. divaricata
nodules may use their large PEPC-derived malate pool to prevent large declines in BNF under low
phosphate conditions. The nodules of V. divaricata were able to offset an excessive drop in BNF,
despite a decline in inorganic phophosphate (Pi) levels. It therefore appears that nodules have
evolved to acquire different mechanisms than roots to adapt to phosphate deficiency in order to
maintain their function. This was achieved via increased regulation of nodule PEPC and its
downstream products. This implies that compared to roots under low P, nodules alter the
metabolism of PEPC derived C, in order to maintain nodule respiration and amino acid synthesis.
This trait could be observed in the synthesis of larger 13C malate pools of nodules compared to
roots, from PEPC, which was underpinned by their different regulation mechanisms of enzyme
activity, of the same protein isoform. Since malate is a potent inhibitor of PEPC activity, roots
appear to have invested in more PEPC protein compared to nodules. In contrast, nodules with
lower PEPC protein, achieved greater enzyme activity than roots, possibly due to higher
phosphorylation in order to reduce the malate effect. The subsequent metabolism of this PEPCderived
malate, caused roots and nodules to synthesise asparagine via different pathways. These
findings imply that roots and nodules under P stress, synthesise their major export amino acid,
asparagine, via different routes. This research has generated new knowledge regarding the
physiological impact of the organic and amino acid metabolism, derived from PEPC-C in the roots
and nodules of legumes growing in nutrient poor ecosystems. It has demonstrated for the first time
that the nodules of legume from a nutrient-poor ecosystem rely on improved resource allocation,
Pi distribution, and PEPC-derived organic acids to maintain the efficient functioning of N
assimilation under P stress. This may be a consequence of having evolved in a nutrient-poor
ecosystem, so that nodule-bacteroid respiration and N metabolism can be maintained in P-poor
soils such as the Fynbos. / AFRIKAANSE OPSOMMING: Tydens fosfaat stremming maak plante gebruik van buigsame kombinasies van morfologiese,
fisiologiese en biochemiese aanpassings. Peulplante is sensitief vir fosfaat tekorte omdat dit die
vermoë om atmosferiese stikstof te kan fikseer, grootliks beïnvloed. Peulplante vanuit ekosisteme
met mineraal-arme gronde, soos Fynbos binne die Kaapse Blommeryk, het ontwikkel in grond met
lae fosfaatvlakke en mag dus unieke aanpassings tot fosfaat tekorte toon. Oor die algemeen is daar
baie min peulplant studies wat fokus op die ondergrondse strukture van wortelknoppies as ‘n plant
orgaan. Nog minder inligting is beskikbaar oor wortelknoppies, van peulplante, vanuit mineraalarme
ekosisteme, se reaksie teenoor ‘n fosfaat tekort. Die doel van hierdie navorsing was om die
metaboliese buigsaamheid van organiese- en aminosuur metabolisme in die (nodulated)
wortelknoppie-wortelstelsel van die Fynbos peulplant Virgilia divaricata, tydens fosfaat tekort te
ondersoek.
Virgilia divaricata wat voorkom in die Kaapse Blommeryk, was gebruik in hierdie studie om die
huidige kennis te verbeter van die essensiële rol wat die sitisoliese ensiem, fosfo-enol piruvaat
karboksilase (PEPC) in fosfo-enol piruvaat metabolisme tydens ‘n fosfaat tekort speel binne die
wortels en wortelknoppies van hierdie peulplant. V. divaricata was gegroei onder glashuis
toestande (20 - 25°C) in gesteriliseerde kwartssand vir 2-3 maande. Die plante was geïnokuleer
met die stikstoffikserende bakterie, Burkholderia phytofirmans, wat geïsoleer is vanaf V.
divaricata wortelknoppies wat in Fynbos grond gegroei is. Twee fosfaatbehandelings, 5μM and
500μM, was toegedien om lae en hoë fosfaat toestande, onderskeidelik, na te boots deur gebruik te
maak van ‘n aangepasde Long Ashton voedingstofmengsel om ‘n ekosisteem, soos die Kaapse
Blommeryk, met lae voedingstofvlakke na te boots. Die wortels en knoppies was geanaliseer ten
opsigte van die groeikinetika, opname en verspreiding van voedingstowwe, ensiemaktiwiteit en
genetiese aanpassings.
Dis is bewys dat tydens fosfaat tekort V. divaricata wortelknoppies minder fosfaat stres ervaar as
die wortels, as gevolg van die verhoogde metaboliese fosfaat bewaringsreaksies tydens organise
suur sintese via die styging in PEPC aktiwiteit. Die styging in PEPC aktiwiteit lei tot ‘n verhoging
in stroomaf metaboliese produkte soos organiese- (appel- en sitroënsuur) en aminosure (glutamaat,
aspartaat en asparagien). Alhoewel biologiese stikstoffiksering verlaag het, kan die hoë
doeltreffendheid daarvan ondersteun word deur díe aangepasde fosfaat bewarings weë asook
verhoogde hulpbron toekenning tydens groei onder lae fosfaat omstandighede. Dit kan dus afgelei word dat die doeltreffendheid van die wortelknoppies via die verhoging in belegging van
hulpbronne en fosfaat opname meganismes in V. divaricata moontlik die sleutel is tot die plant se
vermoë om aan te pas tot omgewings met lae fosfaatvlakke en sodoende die afhanklikheid van
biologiese stikstofbinding te kan onderhou.
Data in hierdie as ook vorige studies, wys dat die fosfaat bewaringsmeganismes in wortels en
wortelknoppies die PEPC-ompad roete, wat nie adenilaat benodig nie, gebruik. 13C NMR het meer
lig gewerp aangaande die vaslegging van koolstof vanaf PEPC na malaat, α-ketoglutaraat en
asparagien. Dit word voorgestel dat V. divaricata knoppies ‘n groot hoeveelheid malaat, afkomstig
van PEPC-werking, gebruik om groot dalings in biologiese stikstofbinding tydens fosfaat tekort, te
verhoed. Die wortelknoppies van V. divaricata kon ‘n oormatige verlaging in biologiese
stikstofbinding voorkom ten spyte van die verlaging in fosfaatvlakke. Dit wil voorkom dat
wortelknoppies ander meganismes as die wortels ontwikkel het om aan te pas tot fosfaat tekort en
sodoende dus hul funksie behou. Dit word bereik deur ‘n verhoging in die regulering van PEPC en
die stroomaf produkte in die wortelknoppies. Dit blyk dat wortelknoppies tydens fosfaat te kort, in
vergelyking met wortels, die metabolisme van die koolstof vanaf PEPC verander om sodoende
respirasie en aminosuursintese te onderhou. Dit wil voorkom dat hierdie meganismes verskil van
die van wortel meganismes.
Hierdie eienskap kan toegeskryf word aan die produksie van ‘n groter hoeveelheid van 13C malaat
vanaf PEPC in die wortelknoppies teenoor die wortels, wat ondersteun word die verskillende
reguleringsmeganismes van ensiemaktiwiteit van dieselfde proteïen isoform. Malaat is ‘n kragtige
inhibeerder van PEPC-aktiwiteit, dus blyk dit dat die wortels belê in meer PEPC proteïene as die
wortelknoppies. In teenstelling, toon die wortelknoppies met laer PEPC proteïene, ‘n hoër ensiem
aktiwiteit as die wortels. Dit kan wees as gevolg van hoër fosforilasie om die effek van malaat te
verlaag. Die metabolisme van die malaat vanaf PEPC het die sintese van asparagien in die wortels
en wortelknoppies via verskillende roetes tot gevolg gehad. Dit impliseer dat tydens ‘n tekort aan
fosfaat, wortels en wortelknoppies hul hoof uitvoer aminosuur, asparagien, deur verskillende
roetes sintetiseer.
Hierdie studie het nuwe kennis aangaande die fisiologiese impak van organiese- en aminosuur metabolisme met koolstof vanaf PEPC in die wortels en wortelknoppies van peulplante wat
voorkom in ekosisteme met lae voedingstofvlakke, voortgebring. Vir die eerste keer is dit bewys
dat die wortelknoppies vanaf peulplante wat voorkom in mineraal-arme ekosisteme, staatmaak op
verbeterde hulpbron beleggings, fosfaat verspreiding en organiese sure vanaf PEPC om die doeltreffendheid van funksionele stikstofassimilasie tydens fosfaat tekort, te onderhou. Dit mag
die gevolg wees van, om in ‘n voedingstof arme ekosisteem te ontwikkel sodat die wortelknoppiebakteroïed
respirasie en stikstofmetabolisme onderhou kan word in fosfaat arme grond soos die Fynbos.
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Recovery of vegetation and bees after removal of pine forests by fire in the Limietberg region of the Cape Floristic Region biodiversity hotspotGardee, Muhammed Nizaar 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: The present global biodiversity crisis is characterized mostly by loss of species due to habitat
destruction but there other major threats – notably invasive alien species. The term “biodiversity hotspot”
has been coined to emphasize areas for conservation prioritization – areas that have high biodiversity under
threat from habitat destruction, invasive species, etc. The Cape Floristic Region (CFR) in the Western Cape
(WC) Province of South Africa has the highest biodiversity of all Mediterranean-type climate regions
globally and is classified among global biodiversity hotspots. The CFR, a Mediterranean-type climate
heathland with a naturally high fire frequency, faces threat from transformation by development, disturbed
(increased) fire frequencies and intensities, and invasive organisms, most notably invasive trees. Such
threats disturb keystone species and keystone processes including insect pollinator assemblages and
associated insect flower visitation webs and frequencies.
Invasive pines are a serious threat to insect flower visitation as pine trees (Pinus spp.) shade out
much indigenous vegetation in the CFR. Little is known of their long-term effects on insect flower visitors
and vegetation recovery in post-pine restoration and recovery areas after such trees are removed. I
investigated the recovery of vegetation and the most important insect pollinator, bees, after the removal of
pines by fire and passive recovery in a CFR valley in the Western Cape.
In 1999, a wildfire burned much of the WC Limietberg Nature Reserve along with an adjacent pine
tree forestry stand - which was then left to recover, providing an ideal opportunity to investigate the enduring
effects of pine afforestation in the CFR. In two data chapters, I compared the post-fire passive recovery of
vegetation (Chapter 2) and bee diversity (Chapter 4) in areas which had previously been planted with pines
vs. those which had contained natural fynbos. To improve on sampling methodology, I conducted an
experiment that demonstrated the Observer Effect in bee sampling with a sweep net (Chapter 3), and I
developed a novel sampling device (Chapter 5) for insect flower visitors.
Sampling of vegetation and bee diversity was conducted in a paired sampling design, where fynbos
(Natural) sub-sites were paired with sub-sites which had previously been afforested with pines (Post-Pine
Recovery; PPR) and the two sub-sites were separated by a distinct, linear boundary (Natural/PPR boundary).
Sampling was conducted along transects parallel to the boundary and extending in both directions from the
boundary into the Natural and in the opposite direction into PPR sub-sites. Five transects were positioned at
3, 10, 20, 30, and 40 m from the boundary (Ecotone) and three were positioned at 60, 80, and 100 m from the
boundary (Deep).
In Chapter 2, I found that natural sub-sites consistently had higher total plant species abundance and
species richness than PPR sub-sites. Approximately two thirds of plant species were more abundant in
Natural sub-sites than in PPR sub-sites. There was no significant correlation in species richness or
abundance with distance from the Natural/PPR boundary. Some genera are cautiously indicated as having lower success in recovery after pine afforestation: Erica spp., Restio spp., Hypodiscus spp. while
Helichrysum spp. is also tentatively indicated to recover well in PPR sub-sites. Soil disturbance and
concomitant disruption of normal ecosystem functions, including pollination, is indicated as a probable
reason for disruption of plant recovery.
In Chapter 3, sweep netting methodology was tested for the Observer Effect. A noticeable increase
in bee visitation frequency to a common generalist plant species in bloom, Metalasia densa, was correlated
with longer waiting periods after I stopped moving indicating the presence of an Observer Effect. This
suggests that sweep netting for bees should only be commenced after a waiting period of five minutes during
which the sweep netter is motionless.
In Chapter 4, using a flight-intercept modified pan trap, I compared bee species richness and bee
species abundance across different seasons and in both mass-flowering and sparser flower patches. There
was no significant difference in bee species richness between Natural and PPR sub-sites. All bee species,
except one complex, were more abundant in Natural sub-sites. Nearly two thirds of all bee species (n=37 of
56) caught with sweep netting and the modified pan trap are undescribed species. Similar to the vegetation,
the effects of soil disturbance as a result of decades of pine forest shading and pine forest litterfall followed
by an unusually hot pine forest fire are indicated as the most likely reasons for lower bee abundance in PPR
sub-sites. This is due to the difficulty associated with viable nest establishment and suitable pollen and
nectar forage availability in disturbed areas.
In Chapter 5, the newly developed Pan and Flight Intercept Combination (PAFIC) trap’s design,
pilot testing, and comparison with the traditional pan trap is discussed. A preliminary test suggests that the
PAFIC trap is more efficient (with higher abundance) than the traditional pan trap.
In Chapter 6, I discuss the implications of the disturbance of pine forestry and unusual pine fire to
plant species and bee species assemblages. Bee-pollination webs in PPR sub-sites are indicated as being
substantially simpler than those in Natural areas as well as compositionally different. The recovery of
pollination as a keystone process in post pine-afforestation areas faces a substantial challenge given the
disturbance to soil that decades of pine afforestation followed by pine forest fire can cause. Some
suggestions are made for the restoration of fynbos areas recovering from pine afforestation including a
discussion of augmenting re-vegetation measures (fynbos seed dispersal and seedling planting) with methods
of restoring of healthy pedogenesis, epigaeic arthropod communities, and fynbos seedbanks. / AFRIKAANSE OPSOMMING: Die huidige globale biodiversiteit krisis is gekenmerk meestal deur die verlies van spesies as gevolg
van die vernietiging van habitat. Maar daar is ook ander groot bedreigings – veral merkbaar indringerspesies.
Die term “biodiversiteit brandpunt” is geskep om gebiede vir bewaring prioritisering te beklemtoon - gebiede
wat 'n hoë biodiversiteit bevat wat bedreig word deur die vernietiging van habitat, indringerspesies, ens. Die
Kaap Floristiese Streek (KFS) in die Wes-Kaap (WK) Provinsie van Suid-Afrika het die hoogste
biodiversiteit van alle Mediterreense tipe klimaat streke wêreldwyd, en is onder die globale biodiversiteit
brandpunte geklassifiseer. Die KFS, 'n Mediterreense-tipe klimaat heideveld met 'n natuurlike hoë brand
frekwensie, word bedreig as gevolg van transformasie deur ontwikkeling, versteurde (verhoogde) vuur
regimes, en indringer organismes, veral indringerbome. Sulke bedreigings versteur hoeksteen spesies en die
hoeksteen prosesse, insluitende insek bestuiwer samestelling en verwante insek blom besoekings webbe en
frekwensies.
Indringer dennebome (Pinus spp.) is 'n ernstige bedreiging vir insek blom besoeking want
dennebome verskaf skaduwee aan baie inheemse plantegroei in die KFS. Min is bekend oor die langtermyn
effekte op insek blom besoekers en plantegroei restorasie na denneboom verwydering en restorasie gebiede
na sodanige bome verwyder word. Ek ondersoek die restorasie van plantegroei en die belangrikste insek
bestuiwer, bye, na die vernietiging van dennebome deur vuur en passiewe herstel in 'n KFS vallei in die
Wes-Kaap.
In 1999 het'n veldbrand baie van die WK Limietberg Natuurreservaat saam met 'n aangrensende
denneboom bosbouplantasie gebrand - wat toe gelaat is om te herstel via intermediêre suksessie na inheemse
fynbos plantegroei. Dit bied 'n ideale geleentheid om die blywende gevolge van denneboom aanplanting in
die KFS te ondersoek. In twee data hoofstukke, vergelyk ek die passiewe herstel van plantegroei na ‘n brand
(Hoofstuk 2) en by diversiteit (Hoofstuk 4) in gebiede wat voorheen geplant is met dennebome teenoor
diegene wat natuurlike fynbos vervat het. Om te verbeter op steekproefmetodiek, het ek 'n eksperiment
onderneem wat demonstreer hoe die Waarnemer Effek by monsterneming met 'n vee-net beïnvloed
(Hoofstuk 3), en het ek 'n nuwe monsterneming toestel ontwerp (Hoofstuk 5) vir insek blom besoekers.
Monsterneming van plantegroei en by diversiteit is uitgevoer in 'n gegroepeerde steekproef ontwerp,
waar fynbos (Natuurlik) sub-terreine gegroepeer is met sub-terreine wat voorheen aangeplant was met
dennebome (Na Denneboom Verwydering Herstel; NDVH) en die twee sub-terreine is geskei deur 'n
duidelike, lineêre grens (Natuurlik / NDVH grens). Steekproefneming is gedoen langs transekte parallel tot
die grens en versprei in albei rigtings van die grens tot binne die natuurlike fynbos en in die teenoorgestelde
rigting tot binne NDVH sub-terreine. Vyf transekte is geposisioneer binne 50 m van die grens (Oorgang
sone) en drie is ver geplaas van die grens (Diep).
In Hoofstuk 2 het ek gevind dat natuurlike sub-terreine konsekwent hoër totale getal plant individue en spesierykheid as NDVH sub-terreine gehad het. Ongeveer twee derdes van plantspesies was meer volop
in natuurlike sub-terreine as in NDVH sub-terreine. Daar was geen beduidende korrelasie in spesierykheid
of totale hoeveelheid plant individue met betrekking tot afstand van die Natuurlike /NDVH grens. Sommige
genera word versigtig aangedui as met laer sukses in die restorasie terreine na denneboom aanplanting: Erica
spp., Restio spp., Hypodiscus spp. terwyl Helichrysum spp. voorlopig aangedui is as goed herstel in NDVH
sub-terreine. Grondversteuring en gepaardgaande ontwrigting van normale funksionering van die
ekosisteem, insluitend bestuiwing, word aangedui as 'n waarskynlike rede vir die ontwrigting van die herstel
van plantegroei.
In Hoofstuk 3 is vee-net metodologie getoets vir die Waarnemer Effek. 'N merkbare toename in by
besoeking frekwensie van 'n algemene plantspesie in blomtyd, Metalasia densa, is gekorreleer met langer
wagtydperke nadat ek gestop het om te beweeg, en dui dus op die teenwoordigheid van 'n Waarnemer Effek.
Dit dui daarop dat die vee-net vir bye eers gebruik moet word na 'n wagtydperk waartydens die waarnemer
bewegingloos verkeer.
In Hoofstuk 4, met behulp van 'n vlug-onderskep gewysigde pan lokval, het ek by spesierykheid en
totale by hoeveelheid vergelyk oor verskillende seisoene en in beide massa-beblomde en yler blom kolle.
Daar was geen beduidende verskil in by spesierykheid tussen natuurlike en NDVH sub-terreine. Alle by
spesies, behalwe een spesie kompleks, was meer volop in natuurlike sub-terreine. Byna twee derdes van alle
by spesies (n = 37 van 56) gevang met vee-nette en die van die gewysigde pan lokvalle is onbeskryfde
spesies. Soortgelyk aan die plantegroei, is die gevolge van grondversteuring as gevolg van dekades van
denneboom bos skadu en denneboom bos blaar afval gevolg deur 'n buitengewoon warm denneboom bos
brand as die mees waarskynlike redes vir laer by hoeveelheid in NDVH sub-terreine aangedui. Dit is as
gevolg van die probleme wat verband hou met lewensvatbare nes vestiging en geskikte stuifmeel en nektar
voer beskikbaarheid in versteurde gebiede.
In Hoofstuk 5 is die nuut ontwikkelde Pan en Vlug Onderskep Kombinasie (PEVOK) lokval
ontwerp, aanvanklike toetsing, en vergelyking met die tradisionele pan lokval bespreek. 'N Voorlopige toets
dui daarop dat die PEVOK lokval meer doeltreffend (met 'n hoër oorvloed) is as die tradisionele pan lokval.
In Hoofstuk 6 bespreek ek die implikasies van die versteuring van denneboom bosbou en ongewone
denneboom vuur met betrekking tot plant spesies en by spesies samestelling. By-bestuiwing webbe in
NDVH sub-terreine word aangedui as wesenlik eenvoudiger as dié in natuurlike areas asook verskillend in
samestelling. Die herstel van bestuiwing as 'n hoeksteen in na denneboom-aangeplante gebiede staar 'n
aansienlike uitdaging in die gesig, gegee die versteuring van grond wat dekades van denneboom aanplanting
gevolg deur denneboom bos brand kan veroorsaak. Sommige voorstelle is gemaak vir die herstel van fynbos
gebiede wat herstel van denneboom aanplanting, insluitend 'n bespreking van die aanvulling van plantegroei
hervestiging maatreëls (fynbos saadverspreiding en saailinge plant) met die metodes van die herstel van 'n
gesonde pedogenese, bogrondse geleedpotige gemeenskappe, en fynbos saadbanke.
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