viii, 21 p. : ill. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / To determine the relative effects of rapid climate change on selection and drift in small populations, nine northern populations of the pitcher-plant mosquito, Wyeomyia smithii, were exposed to directional selection equivalent to 180 years of climate change, while control populations were maintained in their native climate. After three years, fitness had declined in the selected but not the control populations, indicating an adverse effect of climate change. When both selected and control populations were then reared in the selected climate, they showed no difference in fitness, indicating no genetic response to selection. Importantly, however, fitness was negatively correlated with accumulated inbreeding in both control and selected populations, pointing out that the effects of inbreeding and drift exceeded those of selection imposed by rapid climate change. Therefore, small northern populations at expanding edges of species' distributions should be most vulnerable to continued climate change. / Committee in Charge: Dr. William Bradshaw, Chair; Dr. Christina Holzapfel; Dr. Nathan Tublitz

AFRIKAANS: Daar word vasgestel dat Eskom 'n probleem met die spitsverbruik van elektristeit deur die stedelike huishoudelike sektor ondervind en dat die bewoners nie binnenshuise termiese gemak in hul huise ervaar nie. Albei hierdie probleme kan moontlik verminder word deur gebruik te maak van passiewe sonenergieontwerpbeginsels by die ontwerp van huise. Suid-Afrika het 12 klimaatstreke, elk met 'n eie termiese gemaksone waarbinne die bewoners gerieflik kan wees. Die vraag ontstaan of die huise in hierdie streke ontwerp word sodat toestande binne die termiese gemaksone gehou word. Die ontwerpnorme wat deur argitekte in die verskillende klimaatstreke gebruik word, word met die toepaslike Iiteratuur vergelyk en daar word vasgestel dat argitekte nie klimaatstreke en seisoene in ag neem wanneer huise ontwerp word nie. Volgens die argitekte ervaar die bewoners wel binnenshuise termiese gemak. 'n Geografiese Inligtinstelsel word gebruik om die gewenste dT-waardes en maksimum toelaatbare amplitudeverhoudings vir elke klimaatstreek vir somer- en wintertoestande te bepaal. Die bogenoemde twee faktore kan nie onafhanklik van mekaar beskou word wanneer hulle gebruik word vir die aanbeveling van ontwerpnorme vir huise in die verskillende kJimaatstreke nie. ENGLISH: It has been identified that Eskom experiences a problem with urban households' peak hour electricity consumption and that residents do not experience indoor thermal comfort. Both problems could possibly be mitigated by the use of solar passive design principles for houses. South Africa has 12 climatic regions each with its own thermal comfort zone within which indoor thermal comfort can be experienced by residents. The question that is raised is, whether South African houses are designed in order to achieve thermal comfort. During the study the design standards used by architects are compared with those proposed in the relevant literature to obtain thermal comfort. It is determined that architects do not take climatic regions and seasons into consideration when designing houses but according to the architects residents do experience indoor thermal comfort. A Geographical Information System is used to determine the strictest dT values and amplitude ratios for every climatic region in summer and winter. The abovementioned factors can not be used independently when suggesting standards for the design of houses. / Dissertation (MSc (Applied Science))--University of Pretoria, 2007. / Architecture / unrestricted

Ecophysiology studies are needed to predict plant responses in relation to climate change. Variations in salinity and inundation are expected to influence the survival and distribution of salt marsh. The following species were chosen to study as they occur in most South African salt marshes and are representative of different tidal ranges; namely Triglochin buchenaui (lower intertidal), Bassia diffusa (upper intertidal succulent) and Limonium linifolium (upper intertidal non-succulent). To simulate climate change conditions as predicted for South Africa, a 3 x 5 controlled experiment of three inundation levels (tidal, submerged and drought) and five salinity levels (0, 8, 18, 35, 45 ppt) was conducted for each species. This resulted in 15 treatments per species. Plant responses were measured over a three month period. Triglochin buchenaui showed significant variation in height (7.57 ± 0.5 to 29 ± 1.55 cm, p < 0.005, DF = 55) with optimum growth at 0 ppt under tidal conditions; leaf area increments and relative growth rates which decreased with increasing salinity under all inundation states. There was almost a cessation of growth under submergence which reduces the plant’s regeneration potential under these conditions. Proline accumulation (1.84 ± 0.23 to 3.36 ± 0.38 mg l-1), response of photosynthetic pigments and electrolyte leakage (8.17 ± 0.80 to 38.36 ± 7.42 percent) were fundamental to osmotic and membrane response regulation. Plants survived in all inundation states at salinity up to 45 ppt, but the optimum range was 0 to 18 ppt, and best water state was the tidal condition. Viable rhizomes were produced under drought conditions. Bassia diffusa (Thunb.) Kuntze plants under submergence died within one month, irrespective of the salinity. Optimum growth occurred in plants of the tidal treatment at 18 ppt, and reduced with increased salinity and drought conditions. Plants in the tidal treatments were more succulent than the drought-treated plants. There was reduced leaf mass and high anthocyanin concentrations in drought-treated plants and these effects increased with salinity. Soil and leaf water potential were positively correlated with anthocyanin concentration in leaves and stems, suggesting anthocyanin accumulated in response to drought and could be an adaptation to lower the plant’s water potential under drought conditions. A shift of anthocyanin from leaves to stems was found in drought-treated plants, and this possibly enables the maximization of photosynthesis in leaves, to complement its role in osmotic balance and photo-protection. Growth of Limonium linifolium showed that the plant was tolerant to a wide range of salinity under both tidal and drought conditions, but was susceptible to complete submergence, with high membrane damage even in tidal-treated plants. Plants died within 2 weeks of complete submergence. Results further indicated that L. linifolium tolerates extreme drought by accumulating large quantities of proline and oxalic acid, which consequently lowers its water potential for uptake of soil water of high salinity. Excess salts were excreted through salt glands. This is an important adaptation for a plant that thrives in a highly variable saline habitat Further investigation of submergence effects on upper intertidal species using B. diffusa showed three key stages in the response. A drop in chlorophyll a+b within 6 hours (4.2 ± 0.2 to 2.4 ± 0.3 mg l-1) with a corresponding increase in carotenoid concentration (0.6 ± 0.1 mg l-1) indicated an immediate response to submergence. Oxalic acid concentration was highest on Day 4 (13.6 mM) as opposed to control levels, indicative of its role in submergence tolerance, thus Day 4 may be the peak of positive acclimation. The third phase was marked by a sharp increase in electrolyte leakage to 47.5 ± 2.6 percent on Day 10, from 9.4 ± 1.4 percent on Day 7, with a corresponding decrease in total dissolved solutes between Days 7 and 10. Results suggest that oxalic acid accumulates under submergence possibly as a stabilizing osmolyte. The threshold for tolerance of the species under submergence is 7 days with membrane damage thereafter. Bassia diffusa would not survive prolonged submergence (> 7 days) but could survive submergence of short duration (< 7 days) through continuous underwater photosynthesis, accumulation of osmolytes such as oxalic acid and carotenoid, and maintenance of relative water content and succulence within control levels. When considered together, results showed that the two upper intertidal species were sensitive to waterlogging and would not survive complete submergence, whereas the lower intertidal species could in addition to its natural range, thrive in conditions typical of the upper intertidal range, namely prolonged dry conditions and high sediment salinity. These results have important implications for the future management of salt marshes under predicted climate change conditions. In permanently open South African estuaries, a landward migration of salt marsh will be possible if coastal squeeze is limited and the rate of landward recruitment is on par with sea level rise. In this case salt marsh species would retain their current zonation while shifting inland. Increased sea storms and saltwater intrusion could lead to high salinity concentration in the sediment and significantly reduce growth of salt-sensitive plants. In estuaries that are temporarily open to the sea, reduced freshwater inflow will result in an increase in mouth closure, high water levels, prolonged submergence, and consequently die back of salt marsh vegetation. On the other hand increased abstraction and drought would result in low water levels and high sediment salinity which would decrease growth and survival of salt marsh. This research has provided new knowledge on the ecophysiology of salt marsh plants which can be used to predict the responses of plants to climate change.

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Thesis (MSc)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: The development time, survival and fecundity of Trichogrammatoidea cryptophlebiae Nagaraj a, an egg parasitoid of false codling moth, Cryptophlebia leucotreta Meyr., on . citrus were determined at 15,20,25 and 30°C. Using these values the intrinsic rate of increase (rm), mean generation time (T) and net replacement rate (Ra) were estimated at the respective temperatures. In addition, the data were used to estimate the minimum temperature required for development. The rmincreased from 15 (0,042) to 20°C (0,088) and then gradually decreased from 25 (0,069) to 30°C (0,012). The Ra was highest at 20°C (3,116 females/female), followed by 15°C (2,607 females/female), 25°C (1,894 females/female) and 30°C (1,092 females/female). T decreased as temperature increased from 7 days at 30°C to 22,79 days at 15°C. The estimated minimum temperature for development was 7,65°C which implies that this wasp should be able to survive and reproduce under normal winter conditions in the Western Cape. / AFRIKAANSE OPSOMMING: Die ontwikkelingstyd, oorlewing en vrugbaarheid van Trichogrammatoidea cryptophlebiae Nagaraj a, 'n eierparasitoied van valskodlingmot, Cryptophlebia leucotreta Meyr., op sitrus is bepaal by 15, 20, 25 en 30oe. Hierdie waardes is gebruik om die intrinsieke tempo van vermeerdering (rm), die gemiddelde generasietyd (T) en die netto vervangingstempo (Ro) te bepaal by die betrokke temperature. Die data is verder gebruik om die minimum temperatuur vir ontwikkeling te bepaal. Die rm waarde het toegeneem van 15°e (0,042) tot by 200e (0,088) en afgeneem van 25°e (0,069) tot 300e (0,012). Die Ro was die hoogste by 200e (3,116 wyfies/wyfie), gevolg deur 15°e (2,607 wyfies/wyfie), 25°e (1,894 wyfies/wyfie) en 300e (1,092 wyfies/wyfie). T het afgeneem met 'n toename in temperatuur en was 7 dae by 300e en 22,79 dae by 15°e. Die beraamde minimum temperatuur vir ontwikkeling was 7,65°e wat aandui dat hierdie wespe kan oorleef en voortplant by normale wintertoestande in die Wes-Kaap.

About the Book: This selected series of international studies is aimed at achieving a balance between the house and the desert, assuming an energy-conscious future. In the book experimental houses and examples from the world's deserts are discussed, documented and illustrated. The studies were sponsored by the Arid Lands Natural Resources Committee of the University of Arizona.

Thesis (MSc)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Most South African peach and nectarine production areas lack in adequate winter chilling. To address these issues, a conventional breeding programme was started, to develop new and improved stone fruit cultivars with special emphasis on climatic adaptation and pomological attributes. This study was conducted to test the accuracy of the scientific method called the phenological method of classification, currently used by the breeding programme to classify the selections in the second phase of evaluation according to chilling requirement. During April 2000 and May 2001 and continuing until the next spring, 20 oneyear- old shoots of 30 peach and nectarine selections were harvested fortnightly from an evaluation orchard on Bien Donné Experiment Farm, Simondium, Western Cape (34° S). All selections were previously categorised as high (>800 Utah chilling units [CU]), medium (400-800 CU) or _low «400 CU) chilling requirement based on phenologic observations. According to the preliminary classification of the selections included in this study, six selections were classified as high, three as medium and 21 as low chilling requirement. Two replicate bundles of shoots of each selection were prepared and forced at 25° C with continuous illumination until no further changes in bud burst occurred for a period of five days after which the shoots were then discarded. CU in the orchard were calculated according to the Utah and Infruitec models. The hours below 12° C and 7° C were also calculated. For each selection the number of days until 20% vegetative and reproductive bud break was plotted over day of year, Utah CU, Infruitec CU, hours below 12° C, and hours below 7° C, and expressed as a parabolic function. Similarly, the inverse of the number of days until 20% bud break or the rate of bud growth was also plotted against all the above variables. The area under these parabolas was statistically analysed using the CANDISC procedure of SAS Release 8.1. The groupings of the CANDISC procedure were more or less consistent with the preliminary groupings obtained with the phenoligical classification method. On 16 May 2000 and 15 May 2001, 100 one-year-old shoots of the same peach and nectarine selections were harvested from the evaluation orchard on Bien Donné Experiment Farm, covered in wet paper towelling and black plastic bags and placed in a cold room kept at a temperature range between 4° C and 7° C. Two replicate bundles of 10 shoots of each selection were prepared fortnightly and forced at 25° C with continuous illumination until no further changes in bud burst occurred for a period of five days after which the shoots were then discarded. CU accumulated in the cold room at each transferral date was calculated according to the Utah model. For each selection the number of days until 20% vegetative bud break was plotted over Utah CU, and expressed as a parabolic function. Similarly, the inverse of the number of days until 20% bud break or the rate of bud growth was also plotted against the above variables. The area under these parabolas was statistically analysed using the CANDISC procedure of SAS Release 8.1. Once again, the groupings of the CANDISC procedure were more or less consistent with the preliminary groupings obtained with the phenoligical classification method. Due to the nature of the scientific method used in this study, there is room for a certain margin of experimental error to occur, which could account for the misclassifications by the CANDISC procedure, when performed on the 2001 season's data. It can be concluded that the phenological method of classifying the selections, as currently used in the breeding programme, is consistent with the results of the scientific method described here. Therefore, it is recommended that the phenological method be used in future to classify the selections according to chilling requirement (CR), as this method is less time consuming and less costly to perform. Finally the outcome of the analysis of one season's data was used as calibration data against which the other season's data was tested and the consistency of the results, using one set of discriminant functions, was tested. It can be concluded that a unique set of discriminant functions is necessary for each winter season to accurately classify selections according to CR with the CANDISC procedure. / AFRIKAANSE OPSOMMING: 'n Studie van dormansie en koue behoefte van perskes en nektariens Gebrekkige winterkoue is 'n gegewe in die meeste Suid-Afrikaanse perske en nektarien-produksie-streke. Om die gevolge hiervan aan te spreek, is 'n konvensionele teelprogram tot stand gebring om verbeterde steenvrug cultivars te ontwikkel met voortreflike pomologiese eienskappe en wat aangepas is by die plaaslike klimaatstoestande. Hierdie studie is geloods om die akkuraatheid van die wetenskaplike metode, genoem die fenologiese klassifikasie metode, soos tans deur die teelprogram gebruik, waarvolgens seleksies volgens kouebehoefte geklassifiseer word, te toets. Vanaf April 2000 en Mei 2001 tot en met die daaropvolgende lente, is 20 eenjaar-oue lote van 30 perske en nektatrien seleksies twee weekliks in 'n fase 2 evaluasie boord op Bien Donné Proefplaas, te Simondium in die Wes- Kaap (34° S) versamel. AI die seleksies was vooraf op grond van fenologiese waarnemings geklassifiseer in kategorieë van hoog (>800 Utah koue-eenhede [CU]), medium (400-800 CU) of laag «400CU) ten op sigte van kouebehoefte. Hiervolgens val ses van die seleksies wat in die studie ingesluit is in die hoë-, drie in die medium- en 21 in die lae kategorie. Lote van elke seleksie is voorberei en in twee herhalings gebondel, waarna dit geforseer is teen 25° C met deurlopende beligting totdat geen verdere knopbreek vir 'n periode van vyf dae voorgekom het nie, waarna die lote verwyder is. CU in die boord is volgens die Utah en Infruitec modelle bereken. Die aantal uur onder 12° C en onder 7° C is ook bereken. Die aantal dae wat dit elke seleksie geneem het om 20% vegetatiewe en 20% reproduktiewe knopbreek te bereik is bereken en geplot teenoor die dag van die jaar, Utah CU, Infruitec CU, aantal uur onder 12° C en aantal uur onder 7° C en uitgedruk as 'n paraboliese funksie. Die inverse van die aantal dae tot 20% knopbreek, of die tempo van knopbreek, is op soortgelyke wyse geplot teenoor al bogenoemde veranderlikes. Die oppervlakte onder die parabole is statisties ontleed met behulp van die CANDISC prosedure van die SAS program (Vrystelling 8.1). Die groeperings wat met die CANDISC prosedure verkry is het grootliks ooreengestem met die groeperings volgens die fenologiese klassifikasie metode. Op 16 Mei 2000 en 15 Mei 2001, is 100 eenjaar-oue lote van dieselfde perske en nektarien seleksies in die evaluasie boord op Bien Donné versamel, toegedraai in klam handdoekpapier, in swart plastiek sakke geplaas en in 'n koelkamer geplaas waarvan die temperatuur konstant gehou is tussen die grense van 4° C en T" C. Twee herhalings van 10 lote elk, van elke seleksie, is twee weekliks voorberei en geforseer by 25° C met deurlopende beligting totdat geen verdere knopbreek vir 'n periode van vyf dae plaasgevind het nie, waarna die lote verwyder is. Op elke oordragdatum is die aantal CU, wat in die koelkamer geakkumuleer het, volgens die Utah model bereken. Die aantal dae wat dit elke seleksie geneem het om 20% vegetatiewe knopbreek te bereik is bereken en geplot teenoor die Utah CU en uitgedruk as 'n paraboliese funksie. Die inverse van die aantal dae tot 20% knopbreek , dus die tempo van groei, is op soortgelyke wyse bererken en geplot teenoor bogenoemde veranderlikes. Die oppervlak onder die paraboliese funksies is statisties ontleed met behulp van die CANDISC procedure. Die groeperings van die CANDISC prosedure het weereens grootliks ooreengestem met die groeperings wat met die fenologiese metode van klassifikasie verkry is. Weens die aard van die wetenskaplike metode wat tydens hierdie studie gebruik is, kom daar 'n sekere mate van eksperimentele fout voor, wat moontlik die misklassifikasies van die CANDISC prosedure kan verklaar, wanneer dit op die 2001 seisoen se data uitgevoer word. Die gevolgtrekking kan gemaak word dat die resultate van die fenologiese metode, soos dit tans deur die teelprogram gebruik word, ooreenstem met die resultate wat deur die wetenskaplike metode, wat hier beskryf word, verkry is. Dus word daar aanbeveel dat die fenologiese metode in die toekoms gebruik word om die seleksies te klassifiseer volgens koue behoefte (CR), aangesien hierdie metode minder tyd in beslag neem en goedkoper is om uit te voer. Laastens is die resultaat van die analise van een seisoen se data gebruik as kalibrasiedata waarteen die data van die ander seisoen getoets is om so ooreenstemmendheid van die resultate te toets as slegs een stel diskriminant funksies gebruik word. Die slotsom was dat 'n unieke stel diskriminantfunksies nodig is vir elke winter seisoen om die seleksies akkuraat met behulp van die CANDISC prosedure volgens koue-behoefte te klassifiseer.

Please read the abstract in the 00front part of this document / Dissertation (MSc (Environmental Economics))--University of Pretoria, 2007. / Agricultural Economics, Extension and Rural Development / unrestricted