Thesis (MBA)--Stellenbosch University, 2014. / Unemployment and poverty are two key issues that South Africa continues to struggle with. The Expanded Public Works Programme was introduced by Government to not only address these but to half unemployment by 2014. This study assesses the Expanded Public Works Programme’s performance in terms of creating jobs within the Infrastructure Sector in the Western Cape. Since the jobs being created by the Expanded Public Work Programme are only temporary, the study explores what, if any, additional support or training is provided to beneficiaries to aid their exit into long term employment. The findings reveal that unfortunately job creation targets are not being met. Furthermore the training provided to beneficiaries are inadequate to impact their transition into the market. Consequently beneficiaries are left unemployed yet again. Some barriers that the programme encounters include: inefficient institutional arrangements caused by complex and intergovernmental structures, lack of commitment by role-players to implement labour intensive construction methods which are fundamental to the achievement of creating jobs in the infrastructure sector and the lack of delegated authorities driving the objectives of the programme.

Thesis (MscAgric (Viticulture and Oenology))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: Little scientific information regarding the effect of different geological parent materials on grapevine performance is currently available in South Africa. This aspect is of special significance for the Helderberg area, where parent material may change from granite to shale over a short distance. This results in shale- as well as granite-derived soils often occurring within the same vineyard. The objectives of this study were to (i) quantify the nutritional status and other soil properties of different parent materials (shale and granite) and overlying soils (ii) investigate the impact of geological differences in the soil on the vine nutritional status and certain vine parameters. This study was done over two seasons (2006/2007 and 2007/2008). Two Sauvignon blanc and two Cabernet Sauvignon vineyard blocks were selected at two different localities for each cultivar in the Helderberg area, South Africa. Shale- and granitederived soils were identified within each block. Kaolinite was the dominant mineral, whereas quartz and feldspar were sub-dominant. Traces of mica were also present in some shale- and granite-derived soils. Granite- contained significantly higher contents of coarse sand than shale-derived soils, whilst the opposite occurred in terms of fine sand. These differences affected the water holding capacity, in general making it higher in shale- than granite-derived soils. Shale-derived soils had higher concentrations of total K but granite-derived soils had a higher ability to release K as they contained higher concentrations of soluble K. The Q/I parameters, potential buffering capacity of K (PBCK) and equilibrium activity ratio of K (ARK) showed no consistent responses to geological differences. Potassium concentrations were higher in the leaf blades (obtained before harvest in 2007) from Sauvignon blanc grapevines on granite- than on shale-derived soils. Potassium concentrations in the Cabernet Sauvignon juice (obtained in 2007) tended higher in juice from granite- than from shale-derived soils. In 2008, K concentrations tended higher in juice from shale- than from granite-derived soils for both cultivars. The pH of the Sauvignon blanc juice (obtained in 2008) tended higher in juice from shale-than from granite-derived soils, thus corresponding with the K concentrations in the juice in this season. Nitrogen concentrations were higher in Cabernet Sauvignon juice (obtained in 2007) and Sauvignon blanc juice (obtained in 2008) from shalethan from granite-derived soils. In terms of vine water status, vines on granite-derived soils appeared more stressed than those on shale-derived soils in both seasons at one of the vineyards. In these Sauvignon blanc and Cabernet Sauvignon vineyards, the K nutritional status was not affected by geology in a consistent manner but there were some noticeable tendencies for a specific cultivar during certain seasons. On account of vines being planted on shale- and granite-derived soils within the same block, soil preparation was done similarly for both soils, and they were exposed to similar irrigation schedules, canopy management strategies and climatic conditions. Therefore, there is a high probability that all these practices may have negated the effect of geology on the K status of soils and especially on juice K concentration at the time of harvest. It was clear that seasonal differences and fertilisation affected the nutritional status of the vines more than geology. / AFRIKAANSE OPSOMMING: In Suid-Afrika is daar tans min wetenskaplike inligting oor die effek van verskillende geologiese moedermateriale op die prestasie van wingerd beskikbaar. Hierdie aspek is veral van belang in die Helderberg-area, waar moedermateriaal oor ‘n baie kort afstand van graniet na skalie kan wissel. Dit lei daartoe dat skalie-, sowel as granietgronde, dikwels binne dieselfde wingerd voorkom. Die doelwitte van die studie was om: (i) die voedingstatus en ander grondkundige eienskappe van die verskillende moedermateriale (skalie en graniet) en oorliggende gronde te kwantifiseer (ii) die impak van geologiese verskille in die grond op wingerd se voedingstatus en sekere wingerdkundige parameters, te ondersoek. Hierdie studie is oor twee seisoene (2006/2007 en 2007/2008) gedoen. Twee Sauvignon blanc en twee Cabernet Sauvignon wingerdblokke is geselekteer by twee verskillende lokaliteite vir elke kultivar in die Helderbergarea, Suid-Afrika. Beide skalie- en granietgrond is binne elke blok geïdentifiseer. Kaoliniet was die dominante mineraal, met kwarts en veldspaat sub-dominant, terwyl spore van mika ook in beide skalie- en granietgronde gevind is. Granietgronde het betekenisvol hoër hoeveelhede growwe sand bevat, terwyl skaliegronde meer fyn sand bevat het. Hierdie verskille het ‘n effek op waterhouvermoë gehad en daartoe gelei dat waterinhoude oor die algemeen hoër was vir skaliegronde. Skaliegronde het groter hoeveelhede totale K bevat, maar granietgronde se vermoë om K vry te stel was hoër, omdat hulle ‘n hoër konsentrasie oplosbare K bevat het. Die Q/I parameters, potensiële buffervermoë vir K (PBCK) en ewewig aktiwiteitsverhouding vir K (ARK), is nie op ‘n konsekwente wyse deur geologiese verskille beïnvloed nie. Vir die Sauvignon blanc wingerde was kalium konsentrasies in blaarskywe (gemonster voor oes in 2007) hoër vir graniet- as vir skaliegronde. Kalium konsentrasies in die sap vanaf Cabernet Sauvignon (gemonster in 2007) het hoër geneig vir granietgronde. In 2008 het die kalium konsentrasies, vir beide kultivars, hoër geneig in sap vanaf skaliegronde. Gedurende dié seisoen het die pH van sap ook hoër geneig vir Sauvignon blanc vanaf skaliegronde, wat dus ooreenstem met die K inhoud van die sap. Stikstof konsentrasies was hoër in sap vanaf skaliegronde vir Cabernet Sauvignon (2007) en vir Sauvignon blanc (2008). In terme van die wingerde se waterstatus, het stokke op die granietgrond, by een van die lokaliteite, geneig om gedurende beide seisoene onder groter stremming te wees op graniet as op skaliegrond. In hierdie Sauvignon blanc en Cabernet Sauvignon wingerde, is K voedingstatus nie op ‘n konsekwente wyse deur geologie geaffekteer nie, maar gedurende sommige seisoene was daar wel duidelike tendense vir ‘n spesifieke kultivar. Omdat die stokke binne dieselfde blok op skalie- en graniet gronde geplant is, was grondvoorbereiding eenders vir die twee grondtipes terwyl besproeiingskedule, lowerbestuur en klimaatstoestande ook identies was. Daar is dus ‘n hoë waarskynlikheid dat al hierdie faktore daartoe kon bygedra het dat die effek van geologie op die K status van van gronde versluier is, veral die effek op die K inhoud van sap teen oestyd. Dit was duidelik dat seisoenale klimaatsverskile en bemestingspraktyke ’n groter effek as geologie op die voedingstatus van die wingerd gehad het.

Thesis (PhD (Agric) (Conservation Ecology and Entomology))--University of Stellenbosch, 2006. / A study was performed to develop a generic pest monitoring system for sampling the main table grape pests in vineyards in the Hex River Valley, Western Cape Province of South Africa. The presence of phytophagous and predatory mites on cover crop plants was also investigated as this may contribute to biological control of the phytophagous mites in vines. Life table studies for Epichoristodes acerbella (Walker), an important phytosanitary pest, were conducted to determine whether or not this pest was sensitive to high temperatures. Information gained from the latter can also be used for breeding purposes in the possible future development of a sterile insect technique (SIT) programme to control this pest. The sampling system consisted of inspecting 20 plots of five vines per plot per one to two hectares. The top fork of each of the five vines per plot was examined for Planococcus ficus (Signoret) to a distance of within 30 cm of the stem, as well as the distal 15 cm of one cane per vine for the presence of P. ficus and damage caused by Phlyctinus callosus Boh. One bunch per vine was examined for insect damage or presence, and one leaf per vine for the presence of leaf infesting arthropods, such as Tetranychus urticae Koch, P. ficus and Frankliniella occidentalis (Pergande). Corrugated cardboard bands, tied around the stem of one vine per plot, were used to monitor activity of P. callosus. Blue sticky traps, at a density of four to five traps per one to two hectares, were used to monitor activity of F. occidentalis. Pheromone traps, at a density of one trap per one to two hectares, were used to monitor activity of P. ficus, E. acerbella and Helicoverpa armigera (Hübner). All the above-mentioned inspections were done at two-weekly intervals, except traps for E. acerbella and H. armigera, which were inspected weekly. In each of the rows in which the sample plots were situated, one leaf of each of the cover crop plant species was examined for the presence of phytophagous mites and their predators. The abundance and distribution of cover crop plants were determined using a co-ordinate sampling system. Cover crop sampling was done at monthly intervals. The current threshold for P. ficus is 2% stem infestation, which is reached when more than 65 males per pheromone trap are recorded. Counting mealybugs on the sticky pads in the pheromone traps is time consuming. However, the number of grid blocks on the sticky pad with males present can be counted. When P. ficus males are found in 27 blocks on the sticky pad, stem inspections should commence. Due to the spatial association between P. ficus bunch and stem infestation, stem infestation could give an indication of where bunch infestation could be expected. The use of blue sticky traps for predicting halo spot damage, caused by F. occidentalis, is not recommended. The presence of thrips on the vine leaves could not give an indication of where to expect bunch damage, since thrips on the leaves and halo spot damage were not spatially associated. A suitable sampling method for F. occidentalis still needs to be developed. The monitoring system described here can only provide information on the infestation status of the vineyard. For E. acerbella, H. armigera and P. callosus, the traps and cardboard bands could be used to identify vineyards where these pests are present and therefore, where phytosanitary problems may arise. The presence of P. callosus under the bands was spatially associated with P. callosus damage and could be used as an indicator of the latter. The presence of drosophilid flies in the bunches could not be used as an indicator of the presence of E. acerbella in the bunches. If 5% bunch damage is used as an economic threshold for E. acerbella and P. callosus, there will be a good chance of not under spraying if control measures are applied at 1% bunch damage. Epichoristodes acerbella favoured more moderate constant temperatures, with constant temperatures of 28°C and above being unfavourable for development. The economic threshold for Tetranychus urticae Koch is six mites per leaf, or if presence-absence sampling is used, 11 to 29% leaf infestation. Three important predatory mites, that kept T. urticae under control, were found in the Hex River Valley, namely Euseius addoensis (Van der Merwe & Ryke), Neoseiulus californicus (McGregor) and an undescribed phytoseiid in the genus Typhlodromus. Various cover crop plants served as hosts for T. urticae and predatory mites. The presence of these plants created suitable conditions for the survival of these mites and may have influenced their presence on the vine leaves. In the case of phytosanitary pests, both field and pack shed inspections can be used to conclude with a 99% degree of certainty that infestation levels in the pack shed will be 10% or less, since similar results for both methods were obtained. However, more than 20 plots will have to be inspected.

Thesis (PhD)--Stellenbosch University, 2006. / ENGLISH ABSTRACT: This thesis deals with the history of the Berlin Missionary Society (BMS) that commenced their work in 1834 in South Africa. Due to financial reasons the ZuidAfrikaansche Zendinggenootskap (SASG), which coordinated missionary work in South Africa, requested the BMS to take over their activities at the missionary station Zoar in the Little Karoo. Their missionary work ofthe BMS rapidly extended to the neighbouring Amalienstein, then Ladismith, Anhalt-Schmidt (Haarlem), Riversdale, Herbertsdale, Mossel Bay, Laingsburg and Cape Town. Culturally and ethnologically, the field of work of the missionaries of the BMS in the northern provinces differed radically from that of their colleagues in the Western Cape. By 1838 the coloured communities of the Western Cape were already well acquainted with Western culture as well as with the Christian religion. This did not prevent the missionaries from applying a strict pietistic and patriarchal approach towards the coloured people they worked amongst. As the owners of the land on which these missionary stations were established, the missionaries laid down strict rules and regulations and were able to control the spiritual and material behaviour of the members of their congregations. Their approach had two important effects: The mlSSionanes, m emphasising the important role of education, opened doors to better living conditions for the various communities on a short term basis that eventually created socio-economic empowerment. On the other hand, it led to opposition from within these communities, which in later years would have a profound influence on the political mobilisation of the coloured population of the Western Cape. Financial problems and poverty became an integral part of the history of the BMS in the Western Cape- and for that matter, in South Africa. This was especially apparent during the first half of the twentieth century, when two world wars had a devastating effect on their work. The effects during this time on the BMS and the communities they served were two-fold: Due to financial constraints, the BMS increasingly handed over spiritual and educational work to local pastors and teachers. Secondly, the missionaries came to associate themselves with the rise of Afrikaner nationalism. Their low profile in opposing the developing policy of apartheid - and even tacit approval of it - not only led to a break with the committee in Berlin, but also to the estrangement of many of their church members. In 1961, the year in which a republican form of government was established in South Africa and the Berlin Wall was erected, the German Lutheran missionary societies amalgamated to form the Evangelical Lutheran Church of South Africa (ELCSA) and the traditional missionary work of the BMS came to an end. Compared with the missionary activities of the much larger Dutch Reformed Church in the Western Cape, the role of the BMS may seem less relevant. When the impact of the work of the missionaries and their dedicated coloured church members are considered, their contribution to education and human development, is far bigger than their numbers represent. This allows them a place in the history and development of the Western Cape with its cultural diversity. / AFRIKAANSE OPSOMMING: Hierdie proefskrif handel oor die Berlynse Sendinggenootskap (BSG) wat in 1834 in Suid-Afrika begin werk het. Sendingwerk onder die gekleurde gemeenskappe van die Wes-Kaap het in 1838 toevallig begin toe die Zuid-Afrikaanse Zendinggenootskap (SASG) die BSG versoek het om weens finansiele redes die sendingbedrywighede by Zoar in die Klein Karoo oor te neem. Van hier af het die sendingaksie vinnig uitgebrei na die nabygelee Amalienstein en daama na Ladismith, Haarlem in die Langkloof, Riversdal, Herbertsdale, Mosselbaai, Laingsburg en Kaapstad. Kultureel en etnologies het die sendelinge in die Wes-Kaap se bedieningsveld radikaal verskil van die van hulle kollegas in die noordelike provinsies. Die gekleurde gemeenskappe van die Wes-Kaap was teen 1838 alreeds met die Westerse leefwyse en kultuur bekend en was ook reeds in kontak met die Christelike boodskap. Dit het die sendelinge in hierdie gebied - met hulle sterk pietistiese agtergrond - nie verhoed om 'n sterk en streng patriargale benadering ten opsigte van hulle gemeentelede te volg nie. Om woonverblyf op die sendingstasies te bekom moes lidmate van die BSG die reels en regulasies wat die sendelinge neergele het, streng navolg. Hierdeur kon die sendelinge beheer oor hulle gemeentelede se geestelike en materiele lewe uitoefen. Hierdie benadering het twee belangrike uitvloeisels onder die gekleurde gemeenskappe van die Wes-Kaap tot gevolg gehad. Eerstens het dit vir hierdie gemeenskappe opvoedkundige deure oopgemaak wat hulle lewenskwaliteite op korttermyn verbeter het en op 'n langer termyn hulle sosio-ekonomiese posisie verbeter het. Tweedens het dit egter ook tot weerstand gelei waarin die stem van hierdie gemeenskappe vir die eerste keer gehoor is en wat in later jare 'n beduidende invloed op die politieke toekoms van hierdie gemeenskappe sou he. Finansiele probleme en armoede het soos 'n goue draad deur die geskiedenis van die BSG in die Wes-Kaap geloop. Dit was veral die geval gedurende die eerste helfte van die twintigste eeu toe twee Wereldoorloe 'n verwoestende effek op die genootskap se werksaamhede gehad het. Dit het twee belangrike uitvloeisels tot gevolg gehad: Eerstens was die genootskap gedwing om geestelike en opvoedkundige werk al hoe meer aan gekleurde werkers oor te laat- wat op sigself 'n bemagtigingsproses tot gevolg gehad het. Tweedens het die sendelinge van die BSG hulle al hoe meer met opkomende Afrikaner nasionalisme - en dus die ontplooiing van apartheid - vereenselwig wat nie alleen 'n breuk met die komitee in Berlyn tot gevolg gehad het nie, maar ook met hulle gekleurde gemeentelede wat aan die ontvangkant van rassesegregasie en diskriminasie was. Teen die einde van 1961, wat saamgeval het met die oorgang na 'n republikeinse staatsvorm in Suid-Afrika en die oprigting van die Berlynse Muur, het die verskillende Duitse Lutherse sendinggenootskappe saamgesmelt om die Evangeliese Lutherse Kerk van Suid-Afrika (ELKSA) te vorm en het die tradisionele sendingwerk van die BSG in Suid-Afrika tot 'n einde gekom. Gemeet aan die omvang van die werksaamhede van 'n kerkgenootskap soos die NG Kerk in die Wes-Kaap, veral tydens die twintigste eeu, mag die rol van die BSG gering voorkom. Op die langtermyn gesien is die invloed van die Berlynse sendelinge (en hul nageslag wat hulle permanent in Suid-Afrika gevestig het), asook die bruin lidmate van die BSG, in hierdie streek buite verhouding groot; veral ten opsigte van onderwys en opvoeding. Hiermee verdien die Berlynse Sendinggenootskap 'n staanplek in die ryk skakering van die W es-Kaapse geskiedenis.

Thesis (MScConsEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2009. / Habitat loss and fragmentation are two of the most pressing threats to biodiversity. Avifaunal diversity and integrity is under immense pressure from these two processes. We have made major advances in our understanding of avifaunal responses to habitat fragmentation, but mostly focus on either fragment scale and/or landscape scale influences of fragmentation on birds. A more comprehensive approach to assessing the impacts of fragmentation was used in this study. The avifaunas of two different geographical regions and bioregions were surveyed and a multiscale analysis of avifaunal responses to fragmentation was attempted. The study sites include the West Coast and East Coast Renosterveld Bioregions in the Cape Floristic Region, South Africa. Assemblage shifts, feeding guild compositional changes, species abundance variation and species persistence were examined at the three spatial scales. Time- and distance-restricted point counts were used to document birds that were directly dependent on the habitat fragments. Forty fragments were selected in each bioregion and a once-off snapshot of the avifaunal richness and diversity was obtained. Results indicate that the avifauna of the two bioregions responded differently to habitat fragmentation. In the East Coast Renosterveld Bioregion, the assemblages, guild composition and species abundances were most accurately predicted by landscape configuration. An assemblage shift occurred at 20 ha fragment area, compared to the 50 ha fragment area threshold of the West Coast Renosterveld Bioregion’s avifauna composition. In the West Coast Renosterveld Bioregion, fragment area was the better predictor of assemblage, guild composition and species abundances. However in both bioregions, the persistence of common species was equally sensitive to area and landscape scale effects.

Thesis (MScConEcol)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Riparian ecotones, transitional areas between upland terrestrial communities and aquatic ecosystems, are very dynamic and complex ecosystems with intrinsic ecological properties differing in spatial structure, function and temporal dynamics. Riparian habitats along rivers of the Mediterranean south-western Cape are sensitive to environmental change and particularly vulnerable to invasion by invasive alien plants (IAPs), especially nitrogen-fixing Acacia spp., and yet relatively little work has focused on how riparian ecosystems in this region respond to such stressors. The important roles that intact riparian vegetation play in maintaining ecosystem integrity and services have been increasingly highlighted as we acknowledge the degradation of these habitats. While the Working for Water (WfW) programme has been shown to be very successful in eradicating IAPs in riparian zones in the short-term, the extent to which riparian ecosystems recover following alien clearing activities remains poorly understood. The results presented in this study addressed several different aspects of riparian structure and function and acts as a steppingstone for guiding future research and management in riparian zones by adding to the evaluation of the success of clearing initiatives and restoration thereof. The aim of this study was to assess plant functional type (PFT) cover, soil physical and chemical properties, and selected biogeochemical processes in natural, Acacia- invaded and cleared riparian ecotones and associated non-riparian upland fynbos. Fieldwork was performed in mountain and foothill sections of six perennial river systems within the south-western Cape. Eleven sites of three categories were chosen: four natural sites (uninvaded); four moderate to highly invaded sites (predominantly A. mearnsii); and three cleared sites (a formerly invaded site that had been cleared more than 7 years prior to the study). Within each site, four to five replicate plots were established along each of three geomorphological zones (wet bank, dry bank, and upland fynbos). Seasonal soil samples were collected for a period of one year. Results from this study showed that PFT cover and composition, soil physical and chemical properties and rates of nitrogen (N) and phosphorus (P) mineralization differed amongst invasion status, between geomorphological zones and across seasons. Regarding most soil physical and chemical properties and indices N and P cycling, river floodplains (dry banks) were very similar to terrestrial uplands. Acacia spp. changes soil properties and affects plant functional attributes by i) enriching the system with N; ii) enhancing litter inputs; iii) altering soil physical properties; iv) changing the composition and reducing the cover of PFT; and v) enhancing P mineralization rates. Although measured soil physical and chemical properties and N and P mineralization rates were reduced to levels that were similar to or resembled the situation at natural areas, available inorganic N remained two times higher after more than seven years of clearance. Furthermore, cleared areas were characterized by sparse woody cover and a high cover of alien grasses. Correlations between soil silt and clay content and several soil properties measured in this and other studies indicates important linkages between soil texture and resource availability. Clearing Acacia spp. may initiate restoration of invaded riparian ecosystems, but changes in ecosystem function (e.g. elevated soil N availability) as a result of invasion may necessitate active restoration following the removal of the alien species. Active restoration under such conditions would be required to facilitate the restoration of cleared riparian communities. However, we still lack the mechanistic understanding around fynbos riparian recovery after clearing, as the success of restoration may depend on complex interaction and feedback cycles between plants and their physical environment. A greater comprehensive understanding of fynbos riparian ecological processes will not only improve the effectiveness of restoration initiatives by integrating science and management, but also advance the field of riparian ecology. / AFRIKAANSE OPSOMMING: Rivier oewerwal-areas, oorgang gebiede tussen aangrensende terrestriële gemeenskappe en akwatiese ekosisteme, is baie dinamiese en komplekse ekosisteme met intrinsieke ekologiese eienskappe wat verskil in struktuur, funksie (bv. biogeochemie siklusse) en temporale dinamika. Oewerhabitatte langs riviere van die Mediterreense suid-wes Kaap is sensitief vir omgewingsveranderinge en kwesbaar vir indringing deur uitheemse plante (bekend as “invasive alien plants” (IAPs)), veral stikstof-fiksering Acacia spp., en relatief min werk het nog gefokus op hoe ekosisteme in die streek reageer op sulke veranderinge in die omgewing. Die belangrike rol wat gesonde oewerwal plantegroei speel in die handhawing van ekosisteemdienste- en integriteit, is al hoe meer uitgelig soos ons die agteruitgang van hierdie habitat in ag neem. Terwyl die Werk vir Water (WvW)-program al dat baie suksesvol was in die uitwissing van IAPs in oewersones in die kort termyn, is die mate waarin oewer-ekostelsels herstel na skoonmaakaksies swak verstaan. Fynbos oewerwal-areas is grootliks ingeneem deur houtagtige IAPs, veral stikstof fiksering Acacia spp. (soos Acacia mearnsii). Die resultate wat in hierdie studie aangebied is, het verskillende aspekte van oewer- struktuur en funksie aangespreek en dien as middel vir toekomstige navorsing en bestuur van oewerwal ekosisteme deur by te dra tot die evaluering van die sukses van skoonmaak inisiatiewe en die herstelproses daarvan. Die doel van hierdie projek was om die moontlikhede vir herstel van fynbos owerwal-ekostelsels te evalueer deur middel van verskeie grond- fisiese en chemiese eienskappe; plant funksionele groep dekking (genoem ‘plant functional types’ (PFT)); en geselekteerde grond biogeochemie prosesse in natuurlike, Acacia- aangetaste, en skoongemaakte rivierstelsels en nabygeleë terrestriese areas te vergelyk. Veldwerk is gedoen in bergstroom en voetheuwel rivierseksies van ses standhoudende rivierstelsels in Suid-wes Kaap, Suid Afrika. Van uit hierdie geselekteerde rivierstelsels is elf studie areas van drie kategorieë (of indringing status) gekies: vier natuurlike areas (nie aangetas); vier gematig- tot hoogs aangetaste areas (hoofsaaklik A. meanrsii); en drie skoongemaakte areas (rivieroewers wat meer as sewe jaar van te vore skoongemaak is). Binne elke studie area was vier tot vyf soortgelyke persele gevestig by elke van drie breë geomorfologiese sones: naamlik nat-, droë en hoogliggende terrestriese fynbos. Seisoenale grondmonsters vir 'n tydperk van een jaar is geneem. Resultate van hierdie studie het getoon dat PFT dekking en samestelling, grond fisiese- en chemiese eienskappe en N-mineralisasie en suur fosfatase aktiwiteit verskil tussen indringing status, geomorfologiese sones en oor seisoene. Ten opsigte van meeste grond fisiese en chemiese eienskappe en indekse van stikstof (N) en fosfor (P) siklusse kom die rivier vogregimes (droë oewersones) baie ooreen met die terrestriële gebiede. Aan die anderkant is die natbanksones gekenmerk deur grondeienskappe wat baie verskil van die ander twee geomorfologiese gebiede. Die gegewens ondersteun die hipotese dat indringing deur Acacia spp. verskeie grondeienskappe verander en plante se funksionele kenmerke beïnvloed deur i) die sisteem met voedingstowwe te verryk (veral N); ii) verhoog die toevoeging van plantmateriaal; iii) verander grond fisiese eienskappe; iv) verander die samestelling en verminder die dekking van PFT; v) en verhoog P biogeochemie. Hoewel grond fisiese -en chemiese eienskappe, en indekse van N en P mineralisasie verminder is tot vlakke wat soortgelyk aan natuurlike areas, het beskikbare anorganiese N twee keer hoër gebly by skoongemaakte gebiede. Nietemin, voorheen skoongemaakte gebiede is weer-binnegeval deur eksotiese grasse en die regenerasie of hertelling van inheemse fynbos gemeenskappe is taamlik beperk, veral houtagtige oewer struike en bome. Korrelasies tussen grond slik-en klei-inhoud en verskeie grondeienskappe gemeet in hierdie en ander studies dui op belangrike skakeling tussen die grondtekstuur en voedingstof beskikbaarheid. Die opruiming van Acacia spp. mag as aansporing dien vir die herstellingsproses van rivieroewerstelsels, maar veranderinge in die funksie van ekosisteme (bv. verhoogte grond N beskikbaarheid), as gevolg van indringing, mag aktiewe herstel noodsaak nadat die indringer spesies verwyder is. Aktiewe herstel onder sulke omstandighede sal verwag word om die herstel van skoongemaak oewer gemeenskappe te fasiliteer. Ons het wel egter nog 'n gebrek aan die meganistiese begrip in verband met die herstel van fynbos oewerwal areas na opruimings-inisiatiewe, sedert die sukses van herstel kan afhang van komplekse interaksie en terugvoer siklusse tussen die plante en hul fisiese omgewing. ʼn Meer omvattende begrip van fynbos rivieroewer ekologiese prosesse sal nie net die doeltreffendheid van opruimings-inisiatiewe deur die integrasie van wetenskaplike navorsing en bestuur verbeter nie, maar ook vooraf die gebied van rivieroewer-ekologie.

Thesis (MSc)--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: The primary aim of this study was to assess and compare the ecological integrity of the Lourens, Palmiet and Hout Bay Rivers (South Western Cape, South Africa) by examining the macroinvertebrate community structure at a series of representative sampling sites along the course of each river, using the South African Scoring System - Version 5 (SASS-5) rapid bioassessment method. Secondary aims included an examination of the effects of seasonal variability, biotope availability and site-specific environmental variables on the macroinvertebrate community structure at sampling sites, as well as the preliminary testing of the Integrated Habitat Assessment System (IHAS) for aquatic macroinvertebrates. According to results obtained, the ecological integrity of sampling sites in the Mountain Stream Zone of the three rivers was consistently good. The Hout Bay River in the upper portions of the Orange Kloof Reserve was particularly near-pristine, with this area having been identified in this study as a potential biodiversity ‘hot-spot’ for aquatic macroinvertebrates. Downstream of the Mountain Stream Zone, there was a significant deterioration in the ecological integrity of all three rivers due to a number of probable causes. Results based on recorded SASS Scores and Average Score per Taxon (ASPT) values, using ‘biological bands’ generated from reference sites in the South Western Cape, were generally similar to and supported by the corresponding multivariate analyses undertaken. From the results of the various analyses undertaken in this investigation and some of the problems encountered in interpreting the data, a number of recommendations are made regarding future bioassessment studies based on the SASS within the national River Health Programme (RHP). To test the IHAS, secondary data were obtained from reference sites in the Mpumalanga and Western Cape Provinces of South Africa. Assuming that SASS Scores at reference sites are the highest scores attainable, one would expect to find a positive relationship between SASS Scores and IHAS scores at reference sites. The assumption in this investigation was that this relationship should be linear. Non-parametric correlation analyses were undertaken between SASS-4/5 Scores and IHAS scores, using Kendall’s Rank-correlation Coefficient (τ), with separate analyses undertaken for different geomorphological zones and biotope groups. Correlations between SASS Scores and IHAS scores were generally weak (τ-values mostly < 0.3) and unsatisfactory, with no significant correlations (p < 0.05) for two-thirds of the data sets analysed and a wide degree of scatter generally observed amongst data points in respective scatter plots. The performance of the IHAS varied between geomorphological zones and biotope groups, with the Foothill: Gravel-bed Zone in Mpumalanga showing the best results, particularly when the stones-in-current biotope group was analysed separately. Further testing of the IHAS is required to confirm its relative performance in different bioregions/ecoregions, geomorphological zones and biotope groups, which should be undertaken as a priority research area within the RHP. Unsuccessful attempts to test the IHAS by means of multiple regression analyses were undertaken, suggesting that such techniques should be avoided in further testing of the IHAS. / AFRIKAANSE OPSOMMING: Die hoofdoel van hierdie studie was om die ekologiese toestand van die Lourens-, Palmiet- en Houtbaairiviere (Suidwes Kaap, Suid Afrika) te bepaal en te vergelyk deur die bestudering van die makroinvertebraatgemeenskapstruktuur by verteenwoordigende monsterpunte langs die riviere, met gebruik van die “South African Scoring System” – Weergawe 5 (SASS-5) snelle biologiese bepalingsmetode. Sekondêre doelwitte het die bepaling van die gevolge van seisoenele veranderlikheid, biotoop beskikbaarheid en ligging-bepaalde omgewingsveranderlikes op die makroinvertebraatgemeenskapstruktuur by monsterpunte ingesluit, asook die inleidende toetsing van die “Integrated Habitat Assessment System” (IHAS) vir watermakroinvertebrate. Volgens die resultate verkry, was die ekologiese toestand van monsterpunte in die Bergstroomsone van die drie riviere konsekwent goed. Die Houtbaairivier in die boonste gedeelte van die Oranjekloofreservaat was veral feitlik onversteurd en hierdie streek is in die studie as ‘n potensiaal biodiversiteit “hot-spot” vir watermakroinvertebrate geidentifiseer. Stroomafwaarts van die Bergstroomsone was daar ‘n beduidende verswakking in die ekologiese toestand van al drie riviere, as gevolg van ‘n aantal moontlike oorsake. Resultate gebaseer op bepaalde “SASS Scores” en ‘Gemiddelde Waarde per Takson’ (“Average Score per Taxon” - ASPT) waardes, met gebruik van ‘biologiese bande’ wat van verwysingsmonsterpunte in die Suidwes Kaap afgelei is, was oor die algemeen soortgelyk aan en gestaaf deur die ooreenstemmende multiveranderlikke (“multivariate”) statistiese analises wat gedoen is. Uit die resultate van die verskeie analises wat in hierdie ondersoek gedoen is en sommige van die probleme wat in die dataverklaring gevind is, is ‘n aantal aanbevelings gemaak met betrekking tot toekomende biologiese bepalingstudies vir die nasionale Riviergesondheidsprogram (“River Health Programme” - RHP) wat op die SASS gebaseer is. Om die IHAS te toets is sekondêre data van verwysingsmonsterpunte in die Mpumalanga en Wes Kaap Provinsies van Suid Afrika verkry. As aangeneem word dat die “SASS Scores” by verwysingsmonsterpunte die hoogste moontlike tellings is wat bereik kan word, sou ‘n positiewe verwantskap tussen “SASS Scores” en IHAS tellings by verwysingsmonsterpunte verwag word. Die veronderstelling in hierdie studie was dat dié verwantskap lineêr moet wees. Nie-parametriese korrelasieanalise tussen “SASS-4/5 Scores” en IHAS tellings is gemaak, deur gebruik van Kendall se Rangkorrelasiekoëffisiënt (τ), met afsonderlike analises vir verskillende geomorfologiese sones en biotoopgroepe verrig. Korrelasies tussen “SASS Scores” en IHAS tellings was algemeen swak (τ-waardes < 0.3) en onbevredigend, met geen beduidende korrelasies (“p” < 0.05) vir twee-derdes van die datastelle wat geanaliseer is nie en ‘n wye verspreiding tussen datapunte in die onderskeie “scatter plots” wat waargeneem is. Die funksionering van die IHAS was verskillend tussen geomorfologiese sones en biotoopgroepe. Die beste resultate is vir die Voorheuwel: Gruisbeddingsone in Mpumalanga verkry, veral indien die klippe-in-stroom biotoopgroep afsonderlik geanaliseer is. Verdere toetsing van die IHAS is nodig om die relatiewe funksionering in verskillende biostreke/”ecoregions”, geomorfologiese sones en biotoopgroepe te bevestig en dit behoort voorangs te geniet binne die RHP. Pogings om die IHAS deur middel van veelvoudige regressie analise te toets het misluk, wat aandui dat sulke tegnieke vermy moet word in verder toetsing van die IHAS.

Thesis (MScConsEcol(Conservation Ecology and Entomology)--University of Stellenbosch, 2007. / Riparian areas are highly complex systems with varying levels of disturbance that are highly susceptible to invasion by alien plants. Once invaded, riparian areas play a major role in the dispersal and spread of invasive alien plants (IAPs) through the river system and, in some cases, to neighbouring landscapes. Riparian areas have therefore been prioritized by many alien clearing initiatives in South Africa. Current practice for the restoration of cleared areas is minimal and relies mainly on the un-aided recovery of native species from residual individuals and soil stored seed banks. Little research, however, has been done on the effectiveness of this approach or the extent to which riparian seed banks contribute towards community restoration. This study is part of a national research initiative (Targets for Ecosystem Repair in Riparian Ecosystems in Fynbos, Grassland and Savanna Biomes) funded by Department of Water Affairs and Forestry, in collaboration with Working for Water, The Centre for Invasion Biology and the Universities of Cape Town, Stellenbosch, Rhodes and Witwatersrand. The initiative undertook to investigate different restoration techniques on various invaded sites for their cost-effectiveness, efficiency, practicality and conservation integrity. This study has three aims. The first is to determine the composition of seed banks in un-invaded riparian areas within the fynbos biome to be used as a benchmark for future research, restoration grading and other management requirements. The second aim is to determine the composition of seed banks in heavily invaded riparian areas, and thus to assess the impact of invasion on the integrity of the seed banks. The third aim is to evaluate the restoration potential of riparian seed banks following the clearing of invasive alien plants (IAPs). Study sites were selected within four river systems in the south-western part of the Western Cape Province in South Africa: the Berg, Eerste, Molenaars and Wit Rivers. Plots were selected in both invaded (>75% IAP canopy cover; considered “closed” alien stands) and un-invaded (also termed reference, with <25% IAP canopy cover) sections of the river. Replicate plots were established along varying gradients of elevation (mountain stream and foothill) and moisture regimes (dry, wet and transitional bank zones). Soil samples were collected together with above-ground vegetation surveys and comparisons were made. Results from this study confirm those of previous studies that seed banks offer little reference to current aboveground vegetation, but rather offer insight into past vegetation history as well as future vegetation assemblages. Worldwide, many of the species that characteristically form seed banks are early successional species. A community study was done for the seed bank based on the species that germinated and were identifiable at termination of the project (6 months after initiation). Three clusters of species could be identified. One group comprised 32 generalist species that occurred in both reference and invaded sections of the rivers. A second group comprised 39 species associated with invaded sites, and a third group of 40 species that was associated with reference sites. A few sub-community groups were found within both the “reference” and “invaded” community groups which were assumed to be habitat specific. Most species were “pioneer” or relatively-short lived, early-successional species which play a vital role in the initial post-disturbance vegetation cover, and facilitate establishment of later successional species. Seed banks are notoriously variable over space and time, and floristic representation is often biased as a result of differences among species in seed production, dispersal and longevity in the soil. The general consensus is that seeds have an irregular, clustered spatial distribution that is dictated by both biological and environmental factors. Within river systems, the irregular clustering can be exceptionally skewed with the influence of pockets of high sediment deposition along the bank. Environmental factors that were found to significantly skew germination results were the presence of fire, as well as the extent and intensity of invasion (duration and cover). The high level of diversity and abundance in reference Berg River mountain stream seed banks was perceived to be a direct result of a moderate fire frequency (between 8-15 years) and the relatively natural state of the vegetation (i.e. very little invasion). Also, diversity and richness of indigenous species from the Wit and Molenaars Rivers were substantially higher in the invaded samples than the reference samples, probably because both river systems have a long history of invasion and other anthropogenic disturbances which would have an effect on the samples from “reference” sections (i.e. even a 25% presence of IAPs seems adequate enough to alter the composition of the seed bank). Correspondence analyses showed that species had clear affinities towards different levels of “key” riparian environmental variables (fire, invasion and anthropogenic disturbance). Most species were associated with moderate levels of fire frequency, invasion history, and anthropogenic disturbance. Comparisons of seed bank species assemblages between the lateral and longitudinal variables of the rivers offered insights into the habitat requirements of certain fynbos and riparian species. Most significant were the results from bank zone comparisons which showed distinct species groupings along the different moisture bands. As could be expected, riparian species were best represented within the wet bank zones and fynbos species within the dry bank zone, while species characteristic of both zones occurred in the transitional zone, making this seed bank zone the richest in species. Mountain stream sections were richer and more diverse than foothill sections over both invaded and reference samples. This is hypothesised to be linked to lower levels of anthropogenic disturbance experienced in the mountain stream sections. The impact of invasion on the riparian seed bank was most clearly shown through the correspondence analyses for the 20 most frequently occurring species. The seed bank assembly patterns were clearly defined by the state of the river (reference or invaded). Interestingly, this pattern was evident at all three spatial scales; landscape (rivers), reach (mountain stream and foothill sections) and habitat (dry, wet and transitional zones). The reference seed bank assemblage was more tightly grouped, implying that the species were more closely associated with each other and less variable than those of the invaded seed bank assemblages. The species groupings within the invaded seed banks were influenced by variables such as reach and zone, whereas the reference seed bank assemblages seem relatively unaffected by these variables. This implies that the presence of invasive alien plants creates additional variation within the seed bank which alters the natural groupings. At a broad scale, the invaded seed banks were less species rich. This means that not only will the resulting seedling community be harder to predict, but it will also have fewer species. However although generally lower in species richness, the seed banks from almost all invaded rivers interestingly showed a higher diversity of indigenous species than their reference counterparts. This is very promising in terms of rehabilitation of post-cleared riparian sites, but more information is needed to understand the seed bank composition and determine how sustainable the seed banks are for rehabilitation in the long-term. All invaded sections had fewer herbaceous perennial species but more herbaceous annual species. Graminoids made up 50% or more of the seed bank regardless of state (reference or invaded), while woody species (shrubs/shrublets) were generally more prevalent in the reference samples. These results imply that following the removal of invasive alien plants, the vegetation to regenerate from the seed bank is likely to comprise of short-lived, herbaceous species that are not necessarily an accurate reflection of the indigenous riparian community. It is however important to note that this study investigated only the species that were able to germinate over the study period (6 month germination period). Many riparian species may not have been represented because they are either late germinators or may not be present in the soil seed bank at all. In order to gain a holistic understanding of riparian community recruitment, it is recommended that seed bank studies such as this one be included in a more broad scale, long term investigation which takes into account various reproductive strategies used by riparian species. Research of this nature is in its infancy worldwide and there are many challenges involved in measuring diversity and change in these systems. However, within the scope of this study, I suggest that these results shed light on previously unanswered and important questions regarding the ecology of seed banks in the riparian ecosystems of the Western Cape.

Thesis (MScAgric)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Codling moth, Cydia pomonella (L.), infested fluit were collected in a sprayed, unsprayed and an organic orchard. The time of emergence was monitored to see if there was selection for a delayed emergence caused by different treatments. Moths from fruit collected in the sprayed and unsprayed orchards in Desember 2001, had a peak emergence during January 2002 and a smaller peak during February 2002. Moths from fruit collected during February 2002 from an organic orchard, had a peak emergence during February 2002 and an extended emergence from diapause until January 2003. Moths from fluit collected during March 2002 had a peak emergence during November 2002 with an extended emergence in the sprayed orchards until January 2003. Delayed emergence from diapause was observed. Not all the moths from diapause emerged during the first flight, but overlapped with the second flight in December and January. / AFRIKAANSE OPSOMMING: Kodlingmot, Cydia pomonella (L.), geïnfesteerde vrugte is in 'n onbespuite, chemies behandelde en 'n organiese boord versamel. Die tyd van motuitkoms is gemonitor om te bepaal of verskillende behandelings dalk seleksie in die motpopulasie kan veroorsaak ten op sigte van 'n vertraagde motuitkoms. Motte uit vrugte wat in die gespuite boorde in Desember 2001 versamel is, het 'n piek uitkoms in Januarie en 'n kleiner een in Februarie 2002 gehad. Motte uit die ongespuite boord se vrugte, het ook 'n piek uitkoms in Januarie 2002 getoon. Motte uit vrugte wat in Februarie 2002 in 'n organiese boord versamel is, het 'n piek uitkoms in Februarie 2002 gehad, met 'n verlengde uitkoms vanuit diapause vanaf Oktober 2002 tot Januarie 2003. Motte uit vrugte wat in Maart 2002 versamel is, het 'n piek uitkoms in November 2002 gehad. Daar was ook 'n verlengde motuitkoms vanaf diapause by die chemies behandelde boorde tot Januarie 2003. 'n Vertraagde motuitkoms vanaf diapause is waargeneem. Die motte vanuit diapause maak nie almal deel uit van die eerste vlug nie, maar oorvleuelook met motte van die tweede vlug wat gedurende Desember en Januarie in die veld voorkom.

Thesis (MScConEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Heuweltjies are below ground termitaria found along the west coast and the south-western and -eastern Cape. They traversing different climates, soil and vegetation types within the Succulent Karoo and Fynbos biomes. From a birds eye view, heuweltjies appear as near-circular landscape features, demonstrating clear difference in vegetation structure to their surroundings. A study of aspects of the structure and function of heuweltjies, mima-like mounds of south-western South Africa was undertaken. The main aim of the study was to investigate topsoil properties and processes and vegetation structure and the ecophysiology of plants growing on these mounds, and compare it to areas off these patches. Four study sites across a rainfall gradient were chosen for soil and vegetation studies (two within the Succulent Karoo and two at the Fynbos biome). Ten sampling sites on heuweltjies and 10 off heuweltjie (interpatch) were chosen at each study site for these analyses. Soils samples from the top 10 cm were analysed for total nitrogen (N) and carbon (C) content, phosphorus (P) concentrations, particle-size distributions, pH and electrical conductivity (related to salinity). Soil biogeochemistry studies (i.e. potential N mineralization, potential soil respiration and phosphatase activity) were also done in the laboratory. In the field, the cover of soil cryptogams, selected plant growth forms and selected physical variables at each site, on and off heuweltjies, were estimated on 1m2 grids. Two of the study sites, one in the Succulent Karoo and one in Fynbos, were chosen for field measurements of stomatal conductance, predawn and midday xylem water potentials of two growth forms (deciduous and evergreen non-succulent shrubs) at selected times in the duration of the study. Leaf samples were taken to make once-off measurements of specific leaf area, C and N isotope compositions (δ13C, δ15N), and foliar N content. Furthermore, a fertilization experiment that has been running at the Tierberg Karoo Research Centre (Succulent Karoo) since 1997, where 10g m-2 of N have been added to interpatch vegetation twice annually, was included in the stomatal conductance and xylem water potential studies. The aim of including the fertilization experiment was to ascertain whether interpatch vegetation will eventually resemble heuweltjie vegetation in ecophysiology following N fertilization. Soil water probes were inserted, 10 cm deep, on one on heuweltjie and one off heuweltjie site for the long-term estimation of gravimetric water content and temperature at the Tierberg Karoo Research Centre. Heuweltjie soils were found to be hotspots for nutrients and biogeochemical activity. They had elevated levels of total % C, % N and available P (mg kg-1) compared to surrounding interpatch soils. pH and electrical conductivity (μS cm-1) of these soils were also high compared to interpatch areas. Heuweltjie soils have higher silt content and retain more water, and for a longer period following a rainstorm. Potential soil respiration, potential N mineralization and alkaline and acid phosphatase activity were generally higher on heuweltjies.Cover of the selected plant growth forms differed little between heuweltjies and the surrounding vegetation but site differences were observed. Heuweltjies differed from interpatches in the cover of soil cryptogams, with higher cover of mosses and lower cover of lichens on mounds. There was higher cover of plant litter and termite frass on the heuweltjies.There was a decrease in soil available P and increase in non-succulent shrub cover from low to high rainfall areas. On the other hand no significant differences were found in the xylem water potential of interpatch and heuweltjie plants at either of the study sites. At the Tierberg Karoo Research, stomatal conductance of interpatch plants was higher and water use efficiency (δ13C) lower compared to that of heuweltjie plants suggesting some level of water stress for heuweltjie plants at this site. Here, heuweltjie plants also had higher foliar N, lower C/N ratio values, signs of high photosynthetic potential and highly decomposable litter and higher δ15N. At Jonaskop, stomatal conductance and water use efficiency did not differ between heuweltjies and interpatch plants. There were also no differences in foliar N concentrations, C/N ratios and δ15N between heuweltjie and interpatch plants at this site. Plants growing in high N plots (the fertilizer plots) had higher xylem water potential and more variable stomatal conductance than those growing in control plots. The results of this study have shown heuweltjies to be hotspots for nutrients and biogeochemical cycling, and given enough water, will be ideal patches for plant growth. In the Succulent Karoo, high salinity (and finer textured soils) on the heuweltjies may contribute to water stress during dry periods, and together with disturbance, provide bottom-up controls on plant physiology, and ultimately, vegetation structure. In the Fynbos, plants may be limited by nutrients on heuweltjies, possibly because of increased interspecific competition, while increased rainfall may also lead to more nutrients leaching from the topsoils. The results presented are especially relevant to restoration programs, and may shed some light on restoration trajectories after overgrazing, cultivation and mining activities. / AFRIKAANSE OPSOMMING: Heuweltjies is ondergrondse termitaria wat langs die weskus, die suid-wes en oos Kaap van Suid Afrika voorkom. Hulle kom voor onder verskillende klimaatstreke, grondtipes en planttipes wat binne die Sukkulente Karoo en Fynbos biome voorkom. Vanuit die lug uitgesien, verskyn heuweltjies as sirkelvormige landskapseienskappe, wat duidelike verskille in plant struktuur en die omringende omgewing demonstreer. ʼn Studie van aspekte van struktuur enfunksie van ʼn heuweltjies, mima-agtige hope vansuidwestelike Suid-Afrikais onderneem. Die hoofdoel van die studie was om die eienskappe van oppervlakgrondeen -prosesse, plant struktuur, en die ekofisiologie van plante wat op heuweltjies groei te ondersoek, en dit te vergelyk met areas af van hierdie kolle. Vier studieareas wat oor „n reënvalgradient strek is gekies vir grond en plantegroei studies (twee binne die Sukkulente Karoo en twee binne die Fynbos biome). Tien monsterareas op heuweltjies en 10 af van heuweltjies (omringende areas) is gekies binne elke studiearea vir die bogenoemde analises. Grondmonsters van die boonste 10 cm van die grond is geneem en geanalieseer vir totale stikstof (N) en koolstof (C), fosfor (P) konsentrasies, gronddeeltjiegrootte, pH, en elektriese geleidingsvermoë, (hou verband met soutgehalte). Grond biogeochemie studies (d.i. potensiële stikstof mineralisasie, potensiële grond respirasie en fosfatase aktiwiteit) is ook in die laboratorium uitgevoer. In die veld was die dekking van grond kriptogame, geselekteerde plant groeivorms en fisiese veranderlikes by elke lokaliteit, beide op en van heuweltjies op 1m2vierkante bereken. Twee studie lokaliteite, een in die Sukkulent Karoo en een in die Fynbos, is gekies vir veld metings van huidmondjiegeleiding, voor dagbreek en middag xileem potensiale van twee groei vorms (bladwisselende en immergroen nie-sukkulente struike) op geselekteerde tye gedurende die studie. Blaarmonsters is geneem om eenmalige metings te maak van die spesifieke blaararea, C en N isotoop komposisies (δ13C, δ15N), en blaar N inhoud. Verder is „nbemestingseksperiment wat by die Tierberg Karoo Navorsing Sentrum (Sukkulente Karoo) loop sedert 1997, waar 10gm-2 van N jaarliks twee keer bygevoeg word by die plante wat tussen heuweltjies groei ingesluit in die stomata geleiding en xileem water potensiaal studies. Die doel van die bevrugting eksperiment was om vas te stel of die omliggende plante (af van heuweltjies) uiteindelik soos die van die heuweltjiessal lyk in terme van ekofisologie nadat dit met stikstof bemes is. Grondwater monitoreringsapparaat was ingesit (10cm diep) op een op heuweltjie en een lokaliteitaf van die heuweltjie vir die langtermyn bepaling van gravimetriese water inhoud (m3m-3) en temperatuur by die Tierberg Karoo Navorsing Sentrum. Daar is gevind dat grond op heuweltjies “skerpkolle” is vir voedingstowwe en biogeochemiese aktiwiteit. Hulle het ook verhoogte vlakke van totale %C, % N, en beskikbare P (mg kg-1) teenoor die omliggende areas om die heuweltjies. pH en elektriese geleidingsvermoë (μS cm-1) van hierdie gronde was ook hoër in vergelyking met die omliggende areas. Heuweltjie grond het „n hoër sout inhoud gehad en behou meer water vir ʼn langer periode na ʼn reënstorm. Potensiële grond respirasie, potensiële stikstof mineralisasie, en alkaliese en suur fosfatase aktiwiteit is oor die algemeen hoër op heuweltjies. Die voorkoms van die geselekteerde plant groeivorms verskil min tussen heuweltjies en die omliggende omgewing, maar verskille tussen studie areas is opgemerk. Heuweltjies het verskil van areas af van heuweltjies in die voorkoms van grond kriptogame, met ʼn hoër voorkoms van mosse en ʼn laer voorkoms van ligene op die heuweltjies. Daar was hoër voorkoms van plantafvalmateriaal en termiet uitwerpsel op die heuweltjies. Daar was ʼn afname in grond P (mg kg-1) en ʼn toename in nie-sukkulente struik bedekking van lae tot hoë reënval areas. Daar was geen verskil in die xileem water potensiaal van plante op die heuweltjies of af van die heuweltjies by enige van die studie lokaliteite nie. By die Tierberg Karoo Navorsing Sentrum was huidmondjie geleiding van plant in die areas tussen heuweltjies hoër en die water gebruik doeltreffendheid (δ13C) laer in vergelyking met die van die heuweltjie plante, wat op„n sekere vlak waterstres dui in heuweltjie plante by hierdie studiearea. Hier het heuweltjie plante ook hoër blaar N, laer C/N waardes, tekens van hoër fotosintetiese potensiaal en hoogs afbreekbare afvalmaterialgehad asook hoër δ15N. By Jonaskop het huidmondjie geleiding en water gebruik doeltreffendheid nie verskil tussen heuweltjie en omliggende plante nie. Daar was ook geen verskille in blaar N konsentrasies, C/N verhoudings en δ15N tussen heuweltjie en omliggende plante by hierdiestudiearea nie. Plante wat groei in hoë stikstof plotte, het hoër xileem water potensiaal (minder stres) en meer veranderlike stomatal geleiding as die plante wat in die kontrole plotte groei. Die resultate van die studie het getoon dat heuweltjies “skerpkolle” is van voedingstowwe en biogeochemiese siklusse, en gegewe genoeg grondwater, sal ideale areas wees vir die groei van plante. In die Sukkulente Karoodra hoë soutgehalte (en fyner grond teksture) op die heuweltjies by tot water stres gedurende droë tye, en saam met versteurings dra dit by tot grond tot plant kontrole op plantfisiologie, en uiteindelik plant gemeenskapsstruktuur. In die Fynbos word plante op die heuweltjies beperk deur te min voedingstowwe, moontlik omdat daar ʼn toename is in intraspesifieke kompetisie, terwyl hoër reenvalkan lei tot hoër loging van voedingstowwe vanuit die bogrond. Die resultate wat hier gerapporteer word is veral relevant vir restourasieprogramme, en mag lig werp op restourasie trajekte na oorbeweiding, aanplanting van gewasse en mynbou-aktiwiteite.