Dissertations / Theses on the topic 'Drought - South Africa'

The Association for Rural Advancement (AFRA) has run a Drought Project since October 1992. The project's primary focus was to monitor drought conditions in the AFRA's operational area and to assist communities to access relief through providing them with relevant information and helping them to submit proposals to relief agencies. In attempting to do this, it became clear that the effects of drought on rural black communities was not a well understood phenomenon. We also found that relief strategies were informed more by economic, agricultural and meteorological criteria than social ones. This Special Report aims to contribute to the development of a more appropriate drought management strategy, especially with regard to rural communities. In attempting to make this contribution, the Report examines the factors involved in redefining drought and drought relief perspectives in relation to rural communities. However, the range of factors involved and the scarcity of useful information on them, dictate that this is merely an introduction. The complexities and implications arising from the introduction of these factors into drought management in South Africa should be explored on an on-going basis. Because of the scarcity of relevant information about the effects of drought on black rural communities in South Africa, this Report has relied on AFRA's limited monitoring of such communities. Some information was also gathered through Participatory Rural Appraisal (PRA) methods. There were also difficulties in getting information about relief schemes and their operations as most relief agencies were reluctant to release this information. As a result, almost all the relief related information in this Special Report was obtained from publications and reports of the National Consultative Forum on Drought.

Thesis (MScFor)--Stellenbosch University, 2013.
ENGLISH ABSTRACT: The study aims at developing models for predicting aboveground biomass for selected drought tolerant Eucalyptus (E) species (E. cladocalyx, E. gomphocephala and E. grandis x camaldulensis) from the dry west coast. Biomass models were fit for each of the species and a cross-species model was parameterised based on pooled data for all the three species. Data was based on destructive sampling of 28 eucalypt trees which were 20 years of age and additional five five-year old E. gomphocephala trees. Preliminary measurements on diameter at breast height (dbh), height (h) and crown height were recorded in the field. The sampled trees were then felled and samples of discs, branches and foliage were collected. Density of the wood discs and the bark was determined by a water displacement method and computer tomography scanning (CT-scanner). Stem biomass was reconstructed using Smalian’s formula for volume determination and the calculated densities. Upscaling of the crown was carried out by regression equations formulated by employing the sampled branches. Further assessment was carried out on a sub-sample by subjecting the samples to different drying temperatures in a series between 60 and 105ºC. Linear models were parameterised by a simultaneous regression approach based on Seemingly Unrelated Regression (SUR) using the “Systemfit” R statistical package. The predictor variables employed in the study were dbh, d2h and h in which the coefficient of determination (R2), Mean Standard Error (MSE) and Root Mean Standard Error (RMSE) were used to determine the goodness of fit for the models. Akaike Information Criteria (AIC) was also used in the selection of the best fitting model. A system of equations consisting of five models was formulated for each Eucalyptus species. The biomass prediction models had degrees of determination (R2) ranging from 0.65 to 0.98 in which dbh and d2h were the main predictor variable while h improved the model fit. The total biomass models were the best fitting models in most cases while foliage biomass had the least good fit when compared to other models. When the samples were subjected to different drying temperatures, stem wood had the largest percentage change of 6% when drying from 60ºC to 105ºC while foliage had the lowest percentage change of less than 2%.
AFRIKAANSE OPSOMMING: Die doel met hierdie studie is om modelle vir die voorspelling van die bogrondse biomassa van drie droogte-bestande Eucalyptus (E) spesies (E. cladocalyx, E. gomphocephala en E. grandis x camaldulensis), gekweek op die droë kusvlakte in Wes-Kaapland, te ontwikkel. Biomassa modelle vir elk van die spesies is gepas en ’n model gegrond op die gekombineerde data van al drie die spesies, is geparameteriseer. Verder is die biomassa variasie onder verskeie droogingstemperature vasgestel. Die data versameling is uitgevoer gegrond op die destruktiewe mostering van 28 Eucalyptus bome wat 20 jaar oud was en ’n bykomende vyf vyfjarige E. gomphocephala bome. Die aanvanklike mates, naamlik deursnee op borshoogte (dbh), boomhoogte (h) en kroonhoogte is in die veld opgemeet. Die gemonsterde bome is afgesaag en monsters van stamhout skywe, takke en die bas is versamel. Die digtheid van die skywe en die bas is deur die waterverplasing metode, en Rekenaar Tomografie skandering (“CT-scanning”) vasgestel. Stam biomassa is rekonstrukteer deur gebruik te maak van Smalian se formule vir die vasstelling van volume en berekende digtheid. Die opskaal van die kroon biomassa is gedoen met behulp van regressie vergelykings van gekose takmonsters. Submonsters is onderwerp aan ’n reeks van verskillende drogingstemperature tussen 60 en 105ºC. Lineêre modelle is deur ’n gelyktydige regressie benadering gegrond op die Seemingly Unrelated Regression (SUR) wat ’n“Systemfit” R statistiese pakket gebruik, parameteriseer. Die voorspeller veranderlikes wat in hierdie studie gebruik is, is dbh, d2h en h waarin die koëffisient van bepaling (R2), gemiddelde standaardfout (MSE) en vierkantswortel van die gemiddelde standaardfout (RMSE) gebruik is om vas te stel hoe goed die model pas. Akaike Inligting Kriteria is gebruik vir die seleksie van die gepaste model. ’n Reeks vergelykings wat bestaan uit vyf modelle is vir elke Eucalyptus spesie geformuleer. Die biomassa voorspelling model het waardes vir die koëffisiente van bepaling (R2) opgelewer wat strek van 0.65 to 0.98% en waarin dbh en d2h die hoof voorspelling veranderlikes is, terwyl h die pas van die model verbeter. Die totale biomassa model het in die meeste gevalle die beste gepas en die blaarbiomassa die swakste as dit met die ander modelle vergelyk word. Tydens droging vind die grootste persentasie verandering van 6% by stamhout plaas tussen temperature van 60ºC tot 105ºC, en die kleinste persentasie verandering van minder as 2% by blare.

This study investigated the response of the macrophytes in St Lucia Estuary, northern KwaZulu-Natal to drought. The present distribution of vegetation (2010 / 2011) was mapped and changes over time recorded from past aerial photographs. The changes in macrophyte cover in response to environmental factors (sediment and groundwater characteristics) was measured along four transects in 2010 and compared with results from previous years, in 2005 and 2006. In the current study, 1960 images were digitized to illustrate macrophyte distribution and cover of the Narrows, Makakatana and the Eastern Shores during a low rainfall period which started in 1958. The 2001 images were digitized to illustrate vegetation distribution and cover of the same area prior to the current drought which started in June/ July 2002. The 2008 images were digitized to illustrate vegetation distribution and cover of estuarine vegetation within the floodplain during the drought (after 6 years). The sites were visited in June 2011 for verification of the distribution and boundaries of each macrophyte habitat. The area covered by the water column varied over time. In 1960 during a low rainfall period the water was 32705 ha, 33320 ha in 2001 and reduced to 30443 ha in 2008. The area cover of inundated and dry reeds fluctuated with the water level. Under high water levels, low-lying areas such as Fanies Island and Selley‟s Lake were flooded and under low water levels, intertidal sand and mudflats were exposed and colonised by succulent salt marsh (Sarcocornia spp. and Salicornia meyeriana). Similar conditions were observed at Makakatana. Mangroves were observed from the mouth to the Forks. Avicennia marina was the dominant mangrove species and primary colonizer of dredge spoil. The area cover of mangroves in the vicinity of the mouth fluctuated as a result of fluctuating water levels, dredging operations, excavation of the Back Channel and Cyclone Gamede which killed intertidal vegetation. Between 2001 and 2008, mangrove expansion was faster in the Mfolozi Swamps area (± 1.4 ha yr -1) compared to the Narrows (± 0.4 ha yr -1). Long term monitoring transects were set up in 2005, at Makakatana, Charters Creek, Catalina Bay and at Listers Point to document changes in sediment conditions and vegetation cover. These were sampled in July 2005, October 2005, February 2006 and May 2010. Silt was the dominant particle size at Catalina Bay, Charters Creek and Makakatana. At Makakatana, average ground water salinity was 17.2 ± 6.6 ppt, 4.1± 4.9 ppt at Catalina Bay and 32.9 ± 19.3 ppt at Charters Creek. Drought resulted in the accumulation of salt on the surface sediment layer at Listers Point and Charters Creek due to low rainfall. Listers Point, the site with the lowest freshwater input and habitat diversity had the lowest macrophyte species richness with only three species. The dominant species at this site were Sporobolus virginicus and Chenopodium album L. which are highly salt tolerant species. Catalina Bay had the highest species richness (18 to 27); as a result of freshwater input via groundwater seepage from the sand dune aquifers on the Eastern Shores. Along the Eastern Shores, vegetation was dominated by species of Cyperaceae, Juncaceae and Juncaginaceae. Fluctuations in groundwater depth were observed at all sites, Listers Point groundwater depth in February 2006 was 80 cm and the ground water level was not reached during the May 2010 field trip. During the May 2010 field trip, the water column salinity of the St Lucia system was highly variable, Makakatana had the lowest water column salinity of 7.1 ppt, 42.1 ppt at Catalina Bay, 44 ppt at Charters Creek and Listers Point had the highest water column salinity of 95 ppt. An assessment of the changes in macrophyte cover along the transects showed that cover fluctuated in response to rainfall, water level and drought. At Listers Point, there was a continuous decline in the abundance of Sporobolus virginicus over time which was sparsely distributed in the first 40 m of the transect. Sarcocornia natalensis, a succulent and obligate halophyte, was recorded, in areas with high sediment conductivity. In May 2010, bare ground increased to an average percentage cover of 96.5% and was covered with dead organic matter and a salt crust at Listers Point. At Makakatana, there was a significant decrease in bare ground from July 2005 to May 2010 (H = 24.58, N = 197, p<0.001) as bare areas were colonized by salt marsh. Multivariate analysis showed that the abundance of Sporobolus virginicus was positively influenced by sediment moisture content and Paspalum vaginatum abundance was strongly influenced by the water column salinity. At Catalina Bay, low sediment conductivity at the groundwater seepage area resulted in terrestrial vegetation encroaching on estuarine vegetation. Sarcocornia natalensis became more abundant towards the water column. During the period of study, species richness at St Lucia ranged from 2 (Listers Point, May 2010) to 27 (Catalina Bay, February 2006). Salinity and water level fluctuation have a significant impact on the distribution of macrophytes at St Lucia during the drought. In saline areas salt marsh plants have colonized exposed shorelines and along the Eastern Shores groundwater seepage has increased macrophyte species richness. Low water levels have resulted in the exposure and desiccation of submerged macrophytes, which are replaced by macroalgae.

Includes bibliographical references.
Droughts remain a threat to grape yields in South Africa. Previous studies on the impact of climate variability on grape yield in South Africa have focussed on either the rainfall or the impact of temperature on the grape yields; meanwhile, the grape yields may be more influenced by impacts of drought (which is function of water balance) than that of rainfall or temperature. This study investigates the impact of drought on grape yields in the Western Cape. A drought index that is based on water balance (called, Standardized Precipitation Evapotranspiration Index; hereafter SPEI) was used to analyse drought events at both farm and district scale (Robertson, Olifants River and Stellenbosch districts). Correlation analysis was used to identify the association between drought and grape yield. In addition, the performance of a grape yield model (Agricultural Production Systems sIMulator, APSIM) in simulating the grape yield at farm scale and investigating the sensitivity of yields to drought, with and without irrigation was evaluated.

Thesis (MSc)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: Understanding the effects of climate change is one of the cardinal issues within the natural resource management circles. Increased droughts are part of these changes. Afrotemperate forests, as well as their drier Afromontane counterparts suffer from periodic and seasonal droughts respectively. To better understand the effect of droughts on these forests, three key species namely Olea capensis (Iron wood), Podocarpus latifolius (Common Yellow wood) and Pterocelastrus tricuspidatus (Candle wood), were analysed using dendroecologic techniques. Two sites in the Southern Cape were selected according to a West-to-East moisture gradient, with the drier site being close to George and the medium moist site at the Diepwalle estate in the vicinity of Knysna. Growth ring measurements from each of the species were used to calculate basal area and basal area increment during the lifetime of the trees. Drought years for the sites were then selected based on the Standardised Precipitation and Evapotranspiration Index (SPEI), also indicated by the growth during the drought periods. Differences in growth patterns for all three species were observed. An event analysis was then used to quantify the difference in the resistance (Rt), recovery (Rc), resilience (Rs) and relative resilience (RRs). With values standardised around one (Rt, Rc and Rs) and zero (RRs), it was seen that the Candle wood had the highest (~0.92) resistance and the Yellow wood had the highest (~1.3) recovery after the drought. Iron wood stood apart from the other two species in the sense that it only reacted negatively towards the drought one year after the event in most cases. It was concluded that each of the species were significantly different in their reactions towards drought. This specific difference in drought reaction can give way to the possibility that the species together adapted to relieve the stress of a short drought by splitting the available resources over a longer period.
AFRIKAANSE OPSOMMING: Dit is van uiterse belang vir bestuur doeleindes om die veranderende klimaat oor die wêreld te verstaan, insluitend die droogtes wat daarmee gepaard gaan. Die Afrotemperate woud-tipe, asook sy droeër teenstaander, die Afromontane, lei gereeld aan sporadiese en seisonale droogtes. Om hierdie woud-tipe se reaksie tot droogtes beter te verstaan, was drie boom spesies naamlik Ysterhout (Olea capensis), Kershout (Pterocelastrus tricuspidatus) en gewone Geelhout (Podocarpus latifolius), gekies vir die gebruik in ‘n dendro-ekologiese studie. Twee areas was gekies van ‘n wes-tot-oos droogte gradient, met die droeër blok in die George omgewing en die meer vogtige een naby aan Knysna. Die jaarring metings van elke boom was gebruik om beide die basale oppervlakte en die basale oppervlak groei per jaar aan te teken. ‘n Gestandardiseerde reenval en evapotranspirasie indeks (SPEI) was gebruik om vas te stel jare waarin matige tot sterk droogtes gebeur het. Hierdie gekose jare het aanduiding gegee dat daar wel ‘n verskil waargeneem was in die groei patrone van elke spesie gedurende die droogtes. ‘n Gebeurtenis analise is gebruik om ‘n kwantitatiewe verskil te kon sien in die weerstand (Rt), herstel (Rc), weerstandbiedendheid (Rs) en relatiewe weerstandbiedendheid (RRs). Die was waargeneem dat Kerhout die hoogste weerstand (0.92) toon, terwyl die Geelhout ‘n hoër herstel waarde (1.3) gehad het. Ysterhout het apart van die ander twee spesies gestaan in dìe dat dit eers een jaar na die droogte ‘n reaksie getoon het teenoor die droogte. Dit was dus gevind dat daar spesifieke verskil is tussen al drie van die spesies teen opsigte van stres reaksies was. Hierdie verskil kan dan wel ook moontlik aandui dat hierdie spesies en woud-tipe op so ‘n anier aangepas is dat dit die stress gedurende ‘n kort droogte versprei oor ‘n langer tydperk.

Published Article
The objective of this study was to characterize meteorological droughts in the Central Region of South Africa, Modder River Basin, C52A quaternary catchment using two popular drought indices: Standardized Precipitation Index (SPI) and Standardized Precipitation-Evapotranspiration Index (SPEI) and to compare the two indices. Drought events were characterized based on their frequency, duration, magnitude and intensity. The indices were computed for the time-scales that are important for planning and management of water resources, i.e. 3-, 6- and 12-month time-scales. The basic meteorological input data used in the computation of these indices were 57 years (1950-2007) of monthly precipitation and monthly temperature data which were recorded at The Cliff weather station in the quaternary catchment. It was found that both SPI and SPEI responded to drought events in similar fashion in all time-scales. During the analysis period, a total of 37, 26 and 17 drought events were identified in the area based on 3-, 6-, and 12-month times-scales, respectively. Considering event magnitude as severity parameter, results from both indices identified the periods 1984-1985, 1992-1993 and 2003-2005 as the severest drought periods in the area. However, when the effects of both drought duration and magnitude are considered (drought intensity), the most severest drought events were identified during the years 1982/83, 1966 and 1973 based on 3-, 6- and 12-month timescales, respectively. It was concluded that although the SPEI generally exhibits veracity over SPI by including, apart from precipitation, additional meteorological parameter, mean temperature, SPI should be adopted as an appropriate drought monitoring tool in an area, like Africa, where meteorological data are scarce.

Pastoralists in Africa have developed complex mechanisms by which they can alleviate the threat of drought. They practice mobility as one of the strategies to avoid the worst effects of natural stress and disperse grazing pressure. In the past in South Africa, the indigenous Nama people occupied large areas of land and moved around extensively to exploit seasonal differences in the availability of forage and water. With the settlement of the Europeans in the Cape the indigenous people lost most of their land to the colonists. The Nama people were, therefore, restricted to smaller rangelands and their patterns of rangeland use had to adapt to the spatial constraints. Descendants now herd livestock from semi-permanent stockposts that are scattered throughout the commons. Herders use a range of practices to manage their livestock. The aims of this study was to assess the agro-ecological knowledge of livestock keepers
assess the condition of the rangeland during drought
determine the herding strategies of herders during drought.

The Western Cape Province in South Africa recently experienced below-average rainfall during the period 2015−2017, this resulted in a three-year compound hydro-meteorological drought event in the Province. The 2015−2017 Western Cape hydro-meteorological drought was the worst drought event since 1904 and caused severe unprecedented water shortages throughout the Western Cape region, with many municipal water supply systems close to failure by the first quarter of 2018; most especially the Western Cape Water Supply System that serves Cape Town. The drought gained a lot of interest from the public, media and climate scientists alike. The main aim of this study was to assess the extent to which human influence on climate from fossil fuel emissions has changed the likelihood of a hydrometeorological drought event with the magnitude of that experienced in 2015−2017 in the SouthWestern Cape. The Pitman hydrological model was set up for the Berg River catchment in a way that enabled multiple simulations with different rainfall inputs so that attribution experiments could be undertaken. The key differences to the standard Pitman model set up included: (i) constant abstractions, return flows, and land use conditions; (ii) reservoir and dam storages were set to reflect current storage volumes; and (iii) extending the observed rainfall inputs to include the drought period. A hydrological model evaluation was then undertaken, using updated streamflow gauging station data, to assess the ability of the Pitman model to realistically simulate runoff in the Berg River catchment. The model was deemed suitable for the purposes of this study in simulating runoff. To generate the climate attribution experiments, Coupled Model Intercomparison Project Phase 5 historical simulations (1861−2010) were merged with the Representative Concentration Pathway 8.5 greenhouse gas scenario simulations (2011−2100) of rainfall from 77 simulations From 42 models to create a long-term (150 years) time series. Attribution experiments were constructed by considering the average conditions in the 31 year period centred on the years of the event, i.e. 2002−2031 to represent current climate conditions and the period 1861−1890 to represent pre-industrial climate conditions. Five 150-year long stochastic time series of rainfall for each individual simulation were then generated conditioned on observed rainfall characteristics this was done to increase the sample size of the models available. These stochastic rainfall time series were then used as input to the Pitman model to generate outputs/realisations of runoff for a pre-industrial and current world; thus generating impact attribution experiments. To determine the role of anthropogenic climate change on the 2015−2017 hydro-meteorological drought in the South-Western Cape the risk-based approach was applied to the rainfall and runoff attribution outputs. The 2015−2017 meteorological/hydrological drought event was defined in terms of three-year mean annual rainfall/runoff received in the Berg River catchment and its individual 12 quaternary catchments. This event definition was used as a rainfall/runoff threshold in the attribution analysis for the 2015−2017 meteorological/hydrological drought in the South-Western Cape. The three-year minimum averages of rainfall/runoff were identified in each of the 150-yearstochastic time series generated from the 77 simulations; resulting in 385 values for both current and pre-industrial climates for rainfall and runoff. A normal distribution was then fitted to the 385 values of the current and pre-industrial rainfall/runoff. From this distribution, the probability of the current rainfall/runoff occurring, based on the defined threshold, was identified and compared to the pre-industrial time series to calculate the risk ratios of the Berg River catchment and its 12 quaternary catchments. Results show that the risk of the meteorological drought event occurring in the Berg River catchment was increased by a factor of 28.5, 95% confidence interval: 26.0−32.4, (but ranged from 11.5−41.0 in the individual quaternary catchments) due to anthropogenic climate change. The occurrence of the hydrological drought event in the Berg River catchment was found to be increased by a factor of 12.9, 95% confidence interval: 11.3−13.5 (2.7−61.0 in the quaternary catchments) due to anthropogenic climate change. The risk ratio for runoff was higher than for rainfall in the wetter southern quaternary catchments, while it was lower than for rainfall in the drier more northern quaternary catchments. Thus, the human influence on meteorological drought appears to have been amplified in those catchments most important to the Western Cape Water Supply System.

Droughts occurred over South Africa during the summer seasons of 2014/2015 and 2015/2016. At the same time, the Pacific Ocean was warmer than normal starting in 2014 and leading to the very strong 2015/2016 El Niño. The first objective of this study is to document the ocean and climate conditions that occurred during the summer seasons 2014/2015 and 2015/2016 in southern Africa. NCEP Reanalysis data is used to compute the monthly and seasonal scale composite mean and anomalies of large-scale circulations during the summer seasons of 2014/2015 and 2015/2016. Results obtained from the study suggest that some months of 2014/2015 and 2015/2016 were canonical to the effect of El Niño over southern Africa, but not all of them during the summer seasons were dry. The wetter than normal conditions in northeast South Africa, Botswana and Zimbabwe during December 2014 are unfamiliar for a canonical summer El Niño event over southern Africa. Anomalous cooler than normal Sea Surface Temperature (SST) occurred over the west coast and south coast during December 2014 and February 2015, while it is usually warmer during El Niño. Additionally, the colder than normal SST at the south coast during February 2016 and Namibian and West Coast during March 2016 does not mimic the canonical El Niño patterns. However, this did not influence the El Niño-like warmer seasonal SST average during 2015/2016. The lower than normal pressure anomalies over the subcontinent during December 2014 and January 2015 were not portraying a canonical El Niño pattern but the other months were. The seasonal larger than normal pressure at 500 hPa over the subcontinent was more typical of El Niño during summer 2015/2016 and acted to suppress rainfall. Secondly, the study uses the Standard Precipitation Index (SPI) at different time scales (3 months duration, 5 months duration and 17 months duration) to assess the severity of 2015/2016 summer drought compared to the other droughts of the 20th and 21st century (1921 to 2016) and to analyse the relationship between droughts and ENSO. The South African Weather Service (SAWS) rainfall data shows that KwaZulu-Natal was the only region within South Africa, to have the 2015/2016 as the strongest summer drought since 1921 but 2015/2016 was still one of the worst droughts on record in South Africa, especially at the 2 consecutive seasonal scales. In general, droughts are favored by El Niño and wetter conditions by La Niña, but the second strongest El Niño of 1997/1998 led to near normal rainfall over the north-eastern region at all time-scales. The SPI has proven to be very versatile, flexible and very effective to monitor the 2015/2016 summer drought in the complex South African rainfall regime. However, there was little difference between 3 months SPI at the end of February and 5 months SPI at the end of March. For South Africa, the summer rainfall 2015/2016 season had the fifth worst drought after El Niño related drought of 1982/1983 and 1991/1992 and the non-El Niño related droughts of 1967/1968 and 1944/1945. At the 17-month scale, an index that encompasses two summer seasons 2015/2016 was the third worst drought since summer 1921/1922 due to dry conditions in 2014/2015 and 2015/2016.

Thesis (MSc (Forest and Wood Science))--University of Stellenbosch, 2011.
ENGLISH ABSTRACT: This study investigated the use of carbon isotopes as a potential measure for water availability and drought stress in Pinus radiata in the Western and Southern Cape, South Africa. An understanding of water availability and its variation in space is fundamental to the implementation of increasingly site-specific management regimes that have the potential to greatly improve productivity across sites in the region. Fifteen plantation compartments situated on water shedding sites were identified where good weather data existed and a water balance model could be run. In addition, late wood samples were analysed from four co-dominant trees in the same stand to determine the δ13C values of five tree rings, each representing a specific growth year before first thinning. Detailed water balances were constructed for each trial site and drought stress indicators (a) relative canopy conductance (after Granier et al., 2000) and (b) the ratio of actual to potential evapotranspiration (supply / demand ratio), were related to δ13C values in latewood. Maximum available soil water ranged from 52 to 313 mm across trial sites. The water balance model used adequately described soil water availability throughout each growing season and indicated that stand stress due to the lack of available soil water mainly occurred during the summer months of the study period (November to April). The supply / demand ratio for this period as well as the relative canopy conductance proved to be good measures of drought stress. The six-month supply demand ratio (calculated for the period November to April) ranged from 0.04 to nearly 1 (winter rainfall zone) and 0.35 to 1 (all-year rainfall zone) and were strongly related to δ13C values (p < 0.001; r2 = 0.7822). It appears that using δ13C values, it may be possible to classify sites into three water availability classes. This classification may assist in the implementation of intensive silvicultural operations on an increasingly site-specific basis. Where sites are enriched with water from lateral flow or upslope positions, δ13C may be the only reliable technique to quantify soil water availability.
AFRIKAANSE OPSOMMING: Hierdie studie ondersoek die gebruik van koolstof isotope as 'n moontlike maatstaf vir die beskikbaarheid van water en droogtestremming in Pinus radiata in die Wes-en Suid-Kaap, Suid-Afrika. 'n Begrip van die beskikbaarheid van water en die ruimtelike variasie daarvan is fundamenteel vir die implementering van groeiplek-spesifieke bestuur sisteem wat die potensiaal het om baie verbeterde produktiwiteit oor persele in die streek teweeg te bring. Vyftien plantasievakke, geleë op waterskeidingsterreine is geïdentifiseer waar goeie weer data bestaan en 'n water balans model uitgevoer kon word. Daarmee saam is laathout monsters vanuit vier ko-dominante bome in dieselfde kompartement geanaliseer en die δ13C waardes van laathout in vyf jaarringe bepaal wat elk 'n spesifieke jaar van groei voor die eerste dunning verteenwoordig. Gedetailleerde water balanse is vir elke proef perseel bereken en aanwysers van droogtestremming, nl.: (a) relatiewe kroon geleiding (na Granier et al., 2000) en (b) die verhouding van die werklike teenoor potensiële evapotranspirasie (vraag / aanbod verhouding) is gekorreleer met 13C waardes in laat hout. Die maksimum hoeveelheid water beskikbaar op die verskeie proefpersele wissel van 52 tot 313 mm. Die water balans model wat gebruik is beskryf die beskikbare grondwater met genoegsame akkuraatheid. vir die hele groeiseisoen. Die model dui ook aan dat die kompartemente droogtestremming as gevolg van die gebrek aan beskikbare grond water ervaar gedurende die somer maande van die studie tydperk (November tot April). Die vraag / aanbod verhouding vir hierdie tydperk, asook die relatiewe kroon geleiding is geskik om as maatstawwe van droogtestremming gebruik te word. Die vraag / aanbod verhouding (bereken vir die tydperk November tot April) het gewissel van 0,04 tot byna 1 (Winter reënval gebied) en 0,35 tot 1 (die heel jaar reënval sone) en is sterk verwant aan 13C waardes (p <0,001; r2 = 0,7822). Dit blyk dat met die gebruik van δ13C waardes, dit moontlik kan wees om kompartemente te klassifiseer in drie klasse van water beskikbaarheid. Hierdie klassifikasie kan help met die implementering van intensiewe boskultuur bedrywighede op 'n meer vak-spesifieke basis. Waar vakkeverryk is met water vanuit laterale vloei of hoër liggende posisies, mag δ13C dalk die enigste betroubare tegniek wees om die beskikbaarheid van water te kwantifiseer.

>Magister Scientiae - MSc
This work aimed at assessing the response of wetland vegetation productivity to the 2014-2017 climate-induced drought at the Soetendalsvlei wetland system in the Western Cape province of South Africa. To achieve this objective, firstly a literature review on the progress of remotely sensed data applications in assessing and monitoring wetland vegetation productivity was conducted. The review elaborates on the role of remote sensing in monitoring and assessing wetland vegetation productivity, with a detailed discussion of the climate change and variability impacts on wetland vegetation productivity. Accurate assessment results are produced when suitable processing techniques are selected as well as appropriate spatial and spectral resolution for extracting spectral information of wetland vegetation productivity. Secondly, wetland vegetation changes and productivity status was assessed using multi-temporal resolution Landsat series imagery and Normalized Difference Vegetation Index (NDVI) during the wet and dry seasons for the period between 2014 and 2018.

Magister Scientiae - MSc (Environ & Water Science)
Groundwater demand (abstraction) and use during drought continues to be a vital aspect in rural areas. However, the lack of systematic data to assess the availability, demand and use of such resource in addition to lack of having appropriate implementation plan for governing such resources at local scale especially in unmetered areas remain a problem. The argument in this study was that designing appropriate implementation plan that considers local context, informs the basis for implementing local groundwater good governance practice that would sustain utilisation and management of groundwater resources. The Ha-Lambani Village in Limpopo Province of South Africa was used as case study. The aim of this study was to assess rural domestic water demand and use that would inform a basis for designing an appropriate implementation plan for local groundwater good governance as an intervention during drought in rural unmetered areas. To achieve such an aim, i), physiographic factors that influence groundwater availability were explained to establish availability of groundwater; ii), rural domestic water demand and use were assessed to showcase the procedure of generating quantitative data on groundwater abstraction and consumption; iii), factors that determine rural domestic water demand and use were established; iv), appropriate implementation plan for local groundwater governance was designed with evaluation indicators built in. The capability, resilience and sustainable livelihoods approaches were applied as theoretical and conceptual frameworks for the study which informed better understanding of coping strategies during drought.
2019-04-30

Thesis (MBA.) -- University of Limpopo, 2018
This article investigates the effects of drought on small scale beef cattle farmers of Ba- Phalaborwa Municipality in Limpopo Province. Drought and its financial implications have caused critical problems to small scale farmers especially beef cattle farmers in the municipality. Most rural households depend on agriculture as their source of food and income. Agriculture thus plays a prominent role in the stability of rural communities. Drought is a factor that affects farmers not only during the drought season, but also the following season as the previous year’s reduced profits influence the next seasons spending. The changes in price of input commodities the season after drought also affect farmer’s decisions. The main objective of the study was to investigate the effects of drought on small scale beef cattle farmers in Ba-Phalaborwa municipality in Limpopo province. 25 Small scale livestock farmers from Lulekani A and B village in Ba-Phalaborwa municipality were randomly selected to participate in the study. The quantitative study applied a survey design and primary data were collected using open and close ended questionnaires. The findings of the study revealed that drought is a major concern for livestock farmers and the agricultural sector at large, resulting in high loss of livestock due to mortality and enforced sales. Furthermore, due to the devastating effects of drought farmers responses were characterized by the increased reliance on the Department of agriculture and rural development in the form of drought relief. It is therefore recommended that the country needs to prepare for this natural phenomenon and the key to drought preparedness and readiness is about knowing the what, how and when of the drought. To achieve this goal the scientific expertise to monitor and predict, the capability of the observation networks, information systems for drought early warning have to be improved. Furthermore, the provision of financial assistance to address long-term developmental needs (such as investment in water infrastructure and water-harvesting techniques) of the farming community, thereby improving their resilience, may prove more beneficial in the long run than short-term drought relief assistance in the form of fodder supply. Key words: Ba-Phalaborwa, drought, small scale livestock farmers,

Thesis (MA (History))--University of Stellenbosch, 2009.
Although the environment is of obvious and primary importance in agriculture, the historical relationship between agriculture and the environment has not been widely researched. A socio-environmental paradigm provides a useful, inter-disciplinary framework for writing history. It takes into account the fact that ‘natural disasters’ are not merely happening to farmers, governments and communities, subsequently disturbing economic growth-patterns and reverberating amongst policy-makers and politicians. The relationship is much more reciprocal. The environment is not perceived as a player that sometimes disrupts the historical narrative, forcing the plot in a certain direction before returning to the wings. It is rather percieved as an agent within agricultural history. The social-cultural as well as material relationships between people (in this case white farmers), state and the environment are explored as an ecosystem. The thesis focuses on a time period after the First World War to just after the Second World War (c.1920 – c.1950). It asks questions: whom and what has informed the ideas of the state with regards to agriculture and to what extent did it filtered through to the farming communities themselves? The motives behind these approaches are explored. The thesis will also look at how officials translated the policies, legislation and education into what was perceived as functional for the farmers and effective for the environment, tracing how it changed over time. The shifting perception of the farmers about the environment and themselves, and the role of the state played in ‘management’ of the environment are analysed, using press correspondence, marketing campaigns and popular texts. Two themes that garnered much debate in the agricultural sector at the state, farmer and environment interface, include the ‘disasters’ of soil erosion and locust plagues. On the level of ‘scientific agriculture,’ the shift from Europe as a point of reference to the United States is discussed. This is done against the backdrop of South Africa’s semi-arid landscape and how farmers came to grips with this ostensibly hostile environment in an era where mechanisation and urbanisation are thought to have radically altered the conceptualisation of the natural environment.

Chickpea (Cicer arietinum) is an important legume crop globally ranked third after dry bean (Phaseolus vulgaris) and field pea (Pisum sativum). It constitutes 20% of the total global pulse production and around 95% of its production and consumption takes place in developing countries. Major constraints to chickpea production in sub Saharan Africa (SSA) have broadly been related to abiotic stresses, particularly drought and heat stresses, predicted to increase due to the global climatic changes.Dueto the imperativeness of research for identifying heat tolerance markers for potential chickpea genotype selection, in chapter two of the thesis, the response of four chickpea genotypes to a natural temperature gradient in the field was assessed using chlorophyll fluorescence, non-structural carbohydrate, gas exchange and grain yield. Field experiments were carried out in two winter seasons at three locations with known differences in temperature in NE South Africa. Results showed two genotypes (Acc#3 and Acc#7) were tolerant to heat stress with an Fᵥ/Fₘ of 0.83-0.85 at the warmer site, while the two sensitive genotypes (Acc#RR-2 and Acc#8) showed lower Fᵥ/Fₘ of 0.78-0.80. Both chlorophyll fluorescence measurements: dark-adapted Fᵥ/Fₘ and Fq'/Fₘ' (where Fq' =Fₘ'–F) measured at comparable high light levels correlated positively with grain yield. The two tolerant genotypes also showed higher photosynthetic rates,starch, sucrose and grain yield than the sensitive genotypes at the warmer site. However, these parameters were consistently higher at the cooler than at the warmer sites. It was concluded that genotypes Acc#RR-3 and Acc#7 are heat tolerant and chlorophyll fluorescence and leaf carbohydrates are suitable tools for selection of heat tolerant chickpea genotypes under field conditions. The coolest site of Polokwane showed favourable conditions for chickpea production.Heat and drought stresses are two abioticfactors that often occur simultaneously and are predicted to increase, consequently hampering plant growth. Response of different species to either stresses is well documented but information on the response of the same genotypes to both stresses in chickpea is limited. We aimed to determine whether previously noted heat stress tolerant genotype (Acc#7) is drought tolerant and the heat sensitive (Acc#8) is drought sensitive, and whether intermittent moisture supply at vegetative stage would induce priming effect to later drought at flowering. At vegetative stage, plants were divided into three groups, non-stressed (watered to 75% field capacity (FC), severe water stress (moisture-withholding for 14 days) and treated to 40% FC throughout the experiment (mild-stress), with recovery for the severely stressed plants after which they were stressed (double-stress) at flowering. Drought treatments at vegetative and flowering growth stages decreased physiological parameters and biomass accumulation in both genotypesexcept low water supply at 40% FC that decreased biomass in Acc#7 but not Acc#8. Double drought stress resulted in priming effect in Acc#7, having higher biomass, chlorophyll fluorescence, stomatal conductance, net photosynthesis, and relative water content in comparison to the introduction of stress only at flowering growth stage, as well as in comparison to Acc#8. These results showed that both Acc#7 and Acc#8 are sensitive to drought whereas after priming Acc#7 is better acclimated to drought than Acc#8 associated with osmotic adjustment on leaf relative water content (RWC) and higher capacity to protect photosynthetic activity, making Acc#7 potentially ideal for areas associated with intermittent drought spells. This observation, however, disapproved the hypothesis that Acc#7 is more drought tolerant than Acc#8 but is rather better acclimated than Acc#8, because of its superiority only in primed plants and not those stressed only at either vegetative or flowering stages. The findings emphasise the importance of matching chickpea physiological performance to expected rainfall amounts and distribution in drought prone areas during genotype selection. Chapter four of the thesis was an interrogative proteome analysis of the differences in the heat tolerant and sensitive chickpea (Cicer arietinumL.; Fabaceae) genotypes along a temperature gradient under field conditions which will help in identifying the molecular mechanisms involved in the crop's tolerance. Few studies have thus far combined chickpea physiological and proteome analysis to elucidate the changes in abundance and/or activity of relevant enzymes and expression of heat responsive proteins. In this study, analyses of chlorophyll concentrations, gas exchange, flavonoids and anthocyanin concentrations from a chamber experiment, as well as proteomic parameters from field studies in both the heat tolerant and sensitive genotypes are presented. The heat tolerant genotype Acc#7 maintained unaltered physiological performance at flowering growth stage when exposed to high (35/30°C) and moderate (30/25°C) heat stress, under climate chamber conditions compared to the two heat susceptible genotypes (Acc#RR-2 and Acc#8). Results from the proteomic studies showed an up-regulation in proteins related to protein synthesis (e.g. ribulose bisphosphate carboxylase/oxygenase activase), intracellular traffic (e.g. mitochondrial dicarboxylate/tricarboxylate transporter DTC), defence (e.g. HSP70) and transport (e.g. GTP-binding protein SAR1A-like) in heat tolerant Acc#7 compared to the susceptible Acc#8. Results from KEGG analyses support the involvement of probable sucrose-phosphate synthase and sucrose-phosphate phosphatase proteins in the starch and sucrose pathway,that were up-regulated in the heat tolerant genotype Acc#7. This result was in support of our earlier report where tolerant genotype Acc#7 had higher leaf starch and sucrose concentrations in comparison to the susceptible genotype Acc#8. The presence of these differentially regulated proteins including HSP70, ribulose bisphosphate carboxylase/oxygenase activase, plastocyanin and protoporphyrinogen oxidase shows their potential role in field grown chickpea tolerance to heat stress at flowering growth stage. In conclusion, chlorophyll fluorescence (both Fᵥ/Fₘ and Fq'/Fₘ') and leaf carbohydrates were identified as selection markers that can potentially be used for chickpea phenotyping for heat stress under field conditions with the chlorophyll fluorescence parameters correlating positively with seed yield. Due to its higher biomass, chlorophyll fluorescence (Fᵥ/Fₘ), stomatal conductance, net photosynthesis and RWC, heat tolerant genotype Acc#7 was identified to have better adaptive tolerance to drought stress after priming through exposure to intermittent dry spells than Acc#8. Furthermore, under controlled climate chamber conditions, Acc#7 consistently showed characteristics of tolerance to heat stress while Acc#RR-2 and Acc#8 were heat susceptible. Higher chlorophyll fluorescence, grain yield, chlorophyll concentrations, gas exchange, flavonoids and anthocyanin concentrations for Acc#7 compared to Acc#8 in the climate chamber was further validated by the higher up-regulation of proteins involved in protein synthesis, intracellular traffic, defence and transport in Acc#7 compared to Acc#8. The incorporation of proteomics in heat and drought stress studies will potentially help further the understanding of mechanisms by which the crop responds to these stresses.

Thesis (M.Sc. (Pasture Science)) --University of Limpopo, 2014
Due to shortage of adequate pasture in large parts of South Africa, winter survival poses a problem to farmers. A shortage in winter grazing is the major problem on most farms in South Africa. Animals loose weight in winter which leads to low reproduction, production of milk, mutton and meat. The winter feed shortages counteract also the possible good performance of animals during summer. Winter supplementation contributes largely to high input costs in livestock production, which can make this enterprise uneconomically. This study was done at two different localities: Hygrotech’s experimental farm at Dewageningsdrift, Gauteng and Nooitgedacht Agricultural Development center, Mpumalunga. Five winter fodder crop cultivars (Witteberg oats, Overberg oats, LS 35 stooling rye, LS 62 stooling rye and Cloc 1 Triticale) were planted on six planting dates (05 April, 04 May, 06 June, 20 July, 20 August and 26 September). Five cutting treatments were applied on Dewageningsdrift:  First cut 8 weeks after planting and after that re-growth every six weeks (Ct 8),  First cut 10 weeks after planting and after that re-growth every six weeks (Ct 10),  First cut 12 weeks after planting and after that re-growth cut every six weeks (Ct 12),  First cut 14 weeks after planting and after that re-growth cut every six weeks (Ct 14),  First cut when more than 50% of plants were in the reproduction stage (RS). The same cultivars that were used at Dewageningsdrift were used on Nooitgedacht ADC. Only one planting date was applied here that was 02 February 2007. The cutting treatments differed also from that on Dewageningsdrift. Material was cut for the first time when it reached a grazing stage (± 50-60 cm high) and after that re-growth was measured four weeks. The main conclusions from the study were that, Witteberg oats has retained its nutritional value longer than other cultivars. LS 35 stooling rye was an early or short duration growing cultivar, if planted in February to April it will provide grazing early/Mid-winter. However it can also be planted in July to grow in spring. LS 62 stooling rye is a medium to long duration growing cultivar which optimum production period will be in late winter and spring. Witteberg oats is a medium/late producer and a long duration growing cultivar, thus if planted early (April) it can provide grazing until late winter. Overberg oats is an early/med long duration growing type, if planted in April it will produce mid-winter, planted in May to July it will produce late winter and planted in August it will provide spring grazing. Cloc 1 triticale is a long duration growing type. It will produce late winter when planted in April to July and in spring when planted in August/September.

Thesis (MSc)--Stellenbosch University, 2013.
ENGLISH ABSTRACT: In the rainfed areas of the South African sugar industry the unpredictability of rainfall is of major concern for producers. Currently, research into the drought tolerance of South African sugarcane varieties is very limited. Knowledge of varietal drought tolerance potential would allow for more informed decision making when it comes to planting a crop that stays in the ground for between five and fifteen years. The aim of this study was to ascertain the drought tolerance potential of commercial sugarcane varieties using historical field trial data by employing statistical modelling. The first step was to establish a reliable methodology of quantifying the level of drought stress, defined through a drought stress index (DSI), employing the sugarcane growth modelling software Canesim. The second step was to use the selected DSI to evaluate and rate the drought tolerance potential of commercial varieties. Of the six DSI’s calculated, the index comprising a ratio of Canesim simulated rainfed yield (representative of a water stressed environment) to Canesim simulated irrigated yield (representative of a water unstressed environment) was the best at quantifyingthe level of trial drought stress. Using three varieties with previously identified drought potential, two intermediate susceptible (IS) and one intermediate (I) variety, this was the only DSI that was able to quantify all the differences between the varieties. Using the selected DSI, two different methodologies were used to evaluate varietal drought tolerance potential: General linear regression and Residual maximum likelihood meta-analysis. The regression method proved to be a better method of varietal rating when using historical field data. The two rainfed regions, coastal and midlands were analyzed separately due to the difference in climatic conditions. Using the regression analysis, with N12 as the observed intermediate reference variety, coastal varieties were rated as being susceptible (N16, N19, N39 and NCO376) or intermediate (N27, N29, N33, N36, N41, N45, N47). Rating of the midlands varieties, with both statistical methods, were unsuccessful.
AFRIKAANSE OPSOMMING: Binne die droëland produksiegebied van die Suid-Afrikaanse suikerindustrie is die wisselvalligheid van reënval ʼn groot bron van kommer vir produsente. Navorsingsresultate aangaande die droogtetoleransie van Suid-Afrikaanse suikerrietvariëteite is baie beperk. Aangesien suikerriet aanplantings vir vyf tot vyftien jaar in produksie mag bly, is kennis aangaande droogtetoleransie noodsaaklik vir ingeligte besluite rondom variëteit keuse. Die doel van hierdie studie was om die droogtetoleransie van kommersiële variëteite met behulp van historiese veldproef resultate en statistiese modellering te bepaal. Die eerste stap was die ontwikkeling van betroubare metodiek wat die graad van droogtestremming kwantifiseer deur middel van droogtestremmingsindekse (DSI’s) wat met die suikerriet produksiemodel, Canesim, bereken is. Die tweede stap was om die DSI’s te gebruik om geselekteerde kommersiële variëteite vir droogtetoleransie te evalueer en volgens toleransie te rangskik. Van die ses DSI’s wat geëvalueer is, was die indeks wat die verhouding tussen Canesim gesimuleerde droëland opbrengs (verteenwoordigend van ʼn omgewing met droogte) en Canesim gesimuleerde besproeide opbrengs (verteenwoordigend van ʼn omgewing sonder droogte) omskryf het, die mees effektiefste om die graad van droogtestremming te kwantifiseer. Hierdie DSI was vervolgens die enigste wat verskille in droogtetoleransie tussen drie variëteite van bekende droogte toleransie kon kwantifiseer. Deur gebruik van hierdie DSI is twee verskillende metodes aangewend om die droogtetoleransie van variëteite te evalueer naamlik: Algemene Lineêre Regressie en Residuele Maksimum Aanneemlikheid. Die regressiemetode was die mees effektiefste om variëteite volgens droogtetoleransie, op grond van historiese veldproef resultate, te rangskik. Die twee droëland produksiegebiede, naamlik die kusstrook en Natalse Middellande is afsonderlik geanaliseer as gevolg van klimaatsverskille. Met behulp van die regressiemetode is die kus-variëteite as droogtesensitief of -intermediêr geklassifiseer, met N27, N29, N33, N36, N41, N45 en N47 as droogte-intermediêr en N16, N19, N39 en NCO376 as droogtesensitief. Soortgelyke klassifisering van die variëteite wat in die Natalse Middellande verbou word was nie met enige van die statistiese metodes suksesvol gewees nie.

Thesis submitted in partial fulfilment of the requirements for the degree Masters of Technology: Public Management in the Faculty of Business at the Cape Peninsula University of Technology
The focus of the study is the Eden District, George municipal area, Western Cape Province, South Africa, which was severely affected by the worst ever drought in 132 years from 2009-2011 (Bamford, 2009). The reduced rainfall impacted negatively on urban water supplies for the area. In 2009 the Member of the Executive Committee (MEC) for Local Government in the province requested that George Municipality draw up specific measures to be implemented when water resources (in dams and rivers) dropped to certain levels. Plans for possible future drought situations, periods of low rainfall, or insufficient raw water resources, have been done put in place for the needs of the residents of the focus area. The research problem of this study encompasses the assessment of the interventions put in place to address the shortage of water, particularly the implementation thereof, and the strategies and mitigations that contributed to the alleviation of the water shortage. The core objective of the research was to investigate the implementation of the water interventions (water restrictions) authorised to address the water shortages in George, in November 2009. This study employed a qualitative research approach where in-depth interviews were conducted with purposely selected individuals employed in the George Municipality Civil Engineering Services Department, and its Water Services and Disaster Department sections as they could provide first-hand information on the measures implemented to alleviate the problem and on the water shortage status. The research findings indicate that many short-term strategies provided a substantial reduction in overall water usage. The implementation of the strategies and mitigation measures were useful to the various departments in the George Municipality in tangible ways to help manage the water shortages. George Municipality should continue to market water restriction awareness to the public even though the George is no longer experiencing water shortages. The Municipality should adapt to deal with longer and more frequent periods of water shortages. Available tools (e.g. drought policy and by-laws) should be revised and adapted to establish appropriate measures under changing conditions.

Native freshwater fish are in decline worldwide due to human impacts including impoundment, changes to water quality, over-abstraction, climate change and the introduction of non-native species. South Africa's Cape Fold Ecoregion (CFE) harbours exceptionally high freshwater fish endemism, yet the majority of these species are threatened with extinction. The Clanwilliam sandfish (Labeo seeberi), an endangered cyprinid, has declined across its range in the CFE and currently exists in only a handful of tributaries of the Doring River in severely fragmented populations. The last remaining recruiting sandfish population occurs in the Oorlogskloof River, making this tributary one of critical conservation value. In this study, I analysed a six-year dataset comprising fish survey data from 38 sites along 25 km of the Oorlogskloof River to characterise spatio-temporal variation in sandfish abundance and size structure and evaluate the relative influence of different environmental factors on sandfish population trends. The environmental factors considered included other fish in the system, especially three non-native fishes (banded tilapia Tilapia sparrmanii, smallmouth bass Micropterus dolomieu and bluegill sunfish Lepomis macrochirus), temperature, precipitation, habitat characteristics and a range of physicochemical factors. The results show that sandfish have experienced a 93% decline in the sampled stretch of the Oorlogskloof River since 2013 and that the ongoing drought may be preventing recovery. They also suggest that banded tilapia do not adversely affect the Oorlogskloof River sandfish population, while predation of juveniles by smallmouth bass and/or bluegill sunfish apparently reduces the abundance of sandfish, especially of juveniles, where these non-native fish are present. Future studies should attempt to isolate the relative impacts of the different invasive fish species and examine habitat requirements of different sandfish life stages. Management of the river's sandfish population should focus on precautionary actions such as continued monitoring and landowner engagement, as well as clearing dams of non-native species high in the catchment, to prevent the further upstream invasion of smallmouth bass and bluegill sunfish. Proactive measures, such as eradicating smallmouth bass and bluegill sunfish from the Oorlogskloof River, are also necessary to restore connectivity of suitable sandfish habitat in the Doring River system.

The main objective of the study was to assess the extent to which resource-poor households in selected villages of Nkonkobe Local Municipality in the Eastern Cape Province of South Africa are vulnerable to drought by using an improvised remote sensing and Geographic Information System (GIS)-based mapping approach. The research methodology was comprised of 1) assessment of vulnerability levels and 2) the calculation of established drought assessment indices comprising the Normalized Difference Vegetation Index (NDVI) and the Normalized Difference Water Index (NDWI) from wet-season Landsat images covering a period of 29 years from 1985 to 2014 in order to objectively determine the temporal recurrence of drought in Nkonkobe Local Municipality. Vulnerability of households to drought was determined by using a multi-step GIS-based mapping approach in which 3 components comprising exposure, sensitivity and adaptive capacity were simultaneously analysed and averaged to determine the magnitude of vulnerability. Thereafter, the Analytical Hierarchy Process (AHP) was used to establish weighted contributions of these components to vulnerability. The weights applied to the AHP were obtained from the 2012 - 2017 Nkonkobe Integrated Development Plan (IDP) and perceptions that were solicited from key informants who were judged to be knowledgeable about the subject. A Kruskal-Wallis H test on demographic data for water access revealed that the demographic results are independent of choice of data acquired from different data providers (χ2(2) = 1.26, p = 0.533, with a mean ranked population scores of 7.4 for ECSECC, 6.8 for Quantec and 9.8 for StatsSA). Simple linear regression analysis revealed strong positive correlations between NDWI and NDVI ((r = 0.99609375, R2 = 1, for 1985), 1995 (r = 0.99609375, R2 = 1 for 1995), (r = 0.99609375, R2 = 1 for 2005) and (r = 0.99609375, R2 = 1 for 2014). The regression analysis proved that vegetation condition depends on surface water arising from rainfall. The results indicate that the whole of Nkonkobe Local Municipality is susceptible to drought with villages in south eastern part being most vulnerable to droughts due to high sensitivity and low adaptive capacity.

PhDH
Department of Hydrology and Water Resources
Demand for water resources has been on the increase and is compounded by population growth and related development demands. Thus, numerous sectors are affected by water scarcity and therefore effective management of drought-induced water deficit is of importance. Luvuvhu River Catchment (LRC), a tributary of the Limpopo River Basin in South Africa has witnessed an increasing frequency of drought events over the recent decades. Drought impacts negatively on communities’ livelihoods, development, economy, water resources, and agricultural yields. Drought assessment in terms of frequency and severity using Drought Indices (DI) in different parts of the world has been reported. However, the forecasting and prediction component which is significant in drought preparedness and setting up early warning systems is still inadequate in several regions of the world. This study aimed at characterising, assessing, and predicting drought conditions using DI as a drought quantifying parameter in the LRC. This was achieved through the application of hybrid statistical and machine learning models including predictions via a combination of hybrid models. Rainfall and temperature data were obtained from South African Weather Service, evapotranspiration, streamflow, and reservoir storage data were obtained from the Department of Water and Sanitation while root zone soil moisture data was derived from the NASA earth data Giovanni repository. The Standardised Precipitation Index (SPI), Standardised Precipitation Evapotranspiration Index (SPEI), Standardised Streamflow Index (SSI), and Nonlinear Aggregated Drought Index (NADI) were selected to assess and characterise drought conditions in the LRC. SPI is precipitation based, SPEI is precipitation and evapotranspiration based, SSI is based on streamflow while NADI is a multivariate index based on rainfall, potential evapotranspiration, streamflow, and storage reservoir volume. All indices detected major historical drought events that have occurred and reported over the study area, although the precipitation based indices were the only indices that categorised the 1991/1992 drought as extreme at 6- and 12- month timescales while the streamflow index and multivariate NADI underestimated the event. The most recent 2014/16 drought was also categorised to be extreme by the standardised indices. The study found that the multivariate index underestimates most historical drought events in the catchment. The indices further showed that the most prevalent drought events in the LRC were mild drought. Extreme drought events were the least found at 6.42%, 1.08%, 1.56%, and 4.4% for SPI, SPEI, SSI, and NADI, respectively. Standardised indices and NADI showed negative trends and positive upward trends, respectively. The positive trend showed by NADI depicts a decreased drought severity over the study period. Drought events were characterised based on duration, intensity, severity, and frequency of drought events for each decade of the 30 years considered in this study i.e. between 1986 – 1996, 1996 – 2006, 2006 – 2016. This was done to get finer details of how drought characteristics behaved at a 10-year interval over the study period. An increased drought duration was observed between 1986 - 1996 while the shortest duration was observed between 1996 - 2006 followed by 2006 - 2016. NADI showed an overall lowest catchment duration at 1- month timescale compared to the standardised indices. The relationship between drought severity and duration revealed a strong linear relationship across all indices at all timescales (i.e. an R2 of between 0.6353 and 0.9714, 0.6353 and 0.973, 0.2725 and 0.976 at 1-, 6- and 12- month timescales, respectively). In assessing the overall utilisation of an index, the five decision criteria (robustness, tractability, transparency, sophistication, and extendibility) were assigned a raw score of between one and five. The sum of the weighted scores (i.e. raw scores multiplied by the relative importance factor) was the total for each index. SPEI ranked the highest with a total weight score of 129 followed by the SSI with a score of 125 and then the SPI with a score of 106 while NADI scored the lowest with a weight of 84. Since SPEI ranked the highest of all the four indices evaluated, it is regarded as an index that best describes drought conditions in the LRC and was therefore used in drought prediction. Statistical (GAM-Generalised Additive Models) and machine learning (LSTM-Long Short Term Memory) based techniques were used for drought prediction. The dependent variables were decomposed using Ensemble Empirical Mode Decomposition (EEMD). Model inputs were determined using the gradient boosting, and all variables showing some relative off importance were considered to influence the target values. Rain, temperature, non-linear trend, SPEI at lag1, and 2 were found to be important in predicting SPEI and the IMFs (Intrinsic Mode Functions) at 1, 6- and 12- month timescales. Seven models were applied based on the different learning techniques using the SPEI time series at all timescales. Prediction combinations of GAM performed better at 1- and 6- month timescales while at 12- month, an undecomposed GAM outperformed the decomposition and the combination of predictions with a correlation coefficient of 0.9591. The study also found that the correlation between target values, LSTM, and LSTM-fQRA was the same at 0.9997 at 1- month and 0.9996 at 6- and 12- month timescales. Further statistical evaluations showed that LSTM-fQRA was the better model compared to an undecomposed LSTM (i.e. RMSE of 0.0199 for LSTM-fQRA over 0.0241 for LSTM). The best performing GAM and LSTM based models were used to conduct uncertainty analysis, which was based on the prediction interval. The PICP and PINAW results indicated that LSTM-fQRA was the best model to predict SPEI timeseries at all timescales. The conclusions drawn from drought predictions conducted in this study are that machine learning neural networks are better suited to predict drought conditions in the LRC, while for improved model accuracy, time series decomposition and prediction combinations are also implementable. The applied hybrid machine learning models can be used for operational drought forecasting and further be incorporated into existing early warning systems for drought risk assessment and management in the LRC for better water resources management. Keywords: Decomposition, drought, drought indices, early warning system, frequency, machine learning, prediction intervals, severity, water resources.
NRF

MENVSC
Department of Geography and Geo-Information Sciences
South Africa was badly affected by the recent 2015/16 severe drought. Water levels in dams declined drastically resulting in decimation of livestock herds and widespread crop failure. Mopani District Municipality is comprised of many agricultural activities that contribute to the economy and social development of the country. The study evaluated the nature of the drought hazard - its impacts, vulnerability and adaptation strategies employed by rural communities of Mopani District. The study used a mixed method approach with both quantitative and qualitative datasets. The district was divided into two distinct climatic areas, the eastern lowveld which includes the Greater-Giyani, Ba-Phalaborwa and Maruleng Local Municipalities and the western highveld which includes Greater- Tzaneen and Greater- Letaba Local Municipalities. Questionnaires were administered among community members whilst key informant interviews were conducted among relevant government and municipal officials. Anomalies in long term climate data were analysed to determine the frequency and intensity of drought in the district. Drought characterisation was done using a Standardised Precipitation and Evapotranspiration Index whilst vegetation anomaly maps, maize yields and dam level data were used to analyse the impacts of drought across the district. Levels of vulnerability to drought were determined using the Household Vulnerability Index. Spatially distinct patterns of drought conditions across the district were remarkable with wet conditions on the western highveld along the escarpment and harsh dry conditions towards the eastern lowveld. It was found that nearly half the time there is some form of drought or another in the district which may be linked to the remote El Nino phenomenon. Community vulnerabilities have a direct impact on human welfare and different strategies are employed to adapt to drought hazards both at community and district levels. The study showed a link between drought hazard extent and vulnerability. Community members are adapting using conservation agriculture, selling fire-wood, accessing boreholes and rearing chickens, amongst other means to survive in these harsh climatic conditions. Local government intervention strategies include supply of seeds and fertilisers, selling fodder at a cheaper price and supplying water using trucks. The findings of this study contribute to disaster risk reduction efforts in Mopani District Municipality
NRF

A research report for the partial fulfillment of Masters degree in the school of Geography and Environmental studies, Faculty of Science, University of the Witwatersrand, Johannesburg, 2007.
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Drought and its associated impacts have been causing critical problems for agriculture, vulnerable communities and overall development for many years in South Africa. Impacts of drought such as the effects on a regions’ climatology, increases in food insecurity and food prices and the integration of drought with factors such as the HIV/AIDS epidemic have led government to introduce various policies dealing, in particular, with drought risk. By means of examining government documents, journal articles and media publications the methods government has employed to reduce the impacts of drought are traced. The way government has handled drought in the recent past, such as during 1991/92 and 2003/04, with regard to maize farming and vulnerable populations, is of great importance for learning lessons in drought-risk reduction for the future. Lessons Government has learnt include shifting drought management policy and those lost from recent drought episodes include improving early warning systems and incorporating HIV/AIDS in drought strategies. The research also presents suggestions for alleviating the impacts of drought and for better managing the events. The Government, with at least a twenty year history of drought situations and drought governance, provides an interesting range of experience that can present a useful set of cases that may yield valuable insights into the future.

Summaries in English, Afrikaans and Sepedi
The Limpopo Province is a disaster-prone province, with drought being the most common natural disaster. From the year 2012 onwards, the province experienced extremely dry conditions that culminated in a severe drought in 2016. This negatively impacted the livelihoods of smallholder livestock farmers and the welfare of their livestock. The study investigated the coping strategies that were adopted by smallholder livestock farmers during drought conditions and the factors that were associated with animal loss during the drought that affected the region between 2014 and 2016. A randomly selected sample of 281 smallholder livestock farmers aged 18 years and older from the Greater Letaba Local Municipality participated in the study. Structured interviews, aided by questionnaires were used to collect the primary data. Proportions of categorical variables and the mean and standard deviation for continuous variables were computed and presented as tables and figures. A Poisson regression model was fitted to the data to identify factors that were significantly associated with loss of animals during the drought. More than half (55.50%; n=116) of the participants were made aware of the 2014–2016 drought through the agricultural extension officers, followed by 19.14% (n=40) who got to know about it through radio channels. More than half of the participants (58.29%; n=123) were aware of the impending drought. The most common support received from government agencies to help cope with the drought was in the form of animal feed (80%; n=124). Although most of the farmers (73.55%; n=114) benefitted from the support they received, slightly more than half (53.74%; n=151) did not cope well with the drought conditions. While Bellevue (B=-0.199; 95% CI: -0.380 -0.019) was negatively associated with loss of animals, Mokwakwaila (B=0.568; 95% CI: 0.405 0.731) had a strong positive association with loss of animals. Being married (B=-0.060; 95% CI: -0.305 0.183) or divorced (B= -0.035; 95% CI: -0.316 0.246) was negatively associated with loss of animals. Years of experience in farming (B=0.022; 95% CI: 0.010 0.033) and not receiving support during were strongly positively associated with loss of animals (B=0.324; 95% CI: 0.189 0.459). The low number of farmers who were aware of the impending drought and the large number of farmers who did not cope well suggests that many farmers in the area were not prepared for the drought. Groups such as widows, widowers and farmers who have many years of farming experience are high-risk groups and should be targeted for interventions in the event of a drought. More measures are needed to ensure that all agricultural centres are prepared and supported in event of a drought so as to minimise the impact of drought on local communities.
Die provinsie Limpopo is 'n rampgevoelige provinsie, met droogte as die mees algemene natuurramp. Vanaf 2012 het die provinsie uiters droë toestande beleef wat in 2016 op 'n ernstige droogte uitgeloop het. Dit het 'n negatiewe uitwerking gehad op die lewensonderhoud van kleinboere en die welstand van hul vee. Die studie het ondersoek ingestel na die hanteringstrategieë wat deur veeboere in kleinvee tydens droogtetoestande aangeneem is, en die faktore wat verband hou met diereverlies tydens die droogte wat die streek tussen 2014 en 2016 geraak het. 'N Lukraak geselekteerde steekproef van 281 kleinboere van 18 jaar en ouer van die Greater Letaba Local Munisipaliteit het aan die studie deelgeneem. Gestruktureerde onderhoude, gehelp deur vraelyste, is gebruik om die primêre data in te samel. Verhoudings van kategoriese veranderlikes en die gemiddelde en standaardafwyking vir deurlopende veranderlikes is bereken en as tabelle en figure aangebied. 'N Poisson-regressiemodel is op die data toegepas om faktore te identifiseer wat beduidend verband hou met die verlies aan diere tydens die droogte. Meer as die helfte (55,50%; n=116) van die deelnemers is bewus gemaak van die droogte 2014–2016 deur die landbouvoorligtingsbeamptes, gevolg deur 19,14% (n =40) wat dit via radiokanale leer ken het. Meer as die helfte van die deelnemers (58,29%; n=123) was bewus van die dreigende droogte. Die mees algemene steun van regeringsinstansies om die droogte die hoof te bied, was in die vorm van veevoer (80%; n=124). Alhoewel die meerderheid van die boere (73,55%; n=114) voordeel getrek het uit die steun wat hulle gekry het, het die droogtetoestande nie goed hanteer nie (53,74%; n=151). Terwyl Bellevue (B= -0.199; 95% CI -0.380 -0.019) negatief geassosieer is met verlies aan diere, is Mokwakwaila (B= 0,568; 95% CI 0,405 0,731) sterk positief geassosieer met verlies aan diere. Om getroud te wees (B= -0.060; 95% CI -0.305 0.183) of geskei (B= -0.035; 95% CI 0.316 0.246) was negatief geassosieer met verlies aan diere. Jare se ondervinding in die boerdery (B=0,022; 95% CI 0,010 0,033) en om nie ondersteuning gedurende te ontvang nie, was sterk positief geassosieer met die verlies van diere (B=0.324; 95% CI 0.189 0.459). Die lae aantal boere (ongeveer die helfte) wat bewus was van die dreigende droogte, dui daarop dat baie boere in die omgewing nie voorbereid was op die droogte nie. Groepe soos weduwees, wewenaars en boere met baie jare se boerdery-ervaring, is hoërisikogroepe en moet geteiken word vir ingrypings in die geval van 'n droogte. Meer maatreëls is nodig om te verseker dat alle landbousentrums voorberei en ondersteun word in geval van 'n droogte om die impak van droogte op plaaslike gemeenskappe te verminder.
Komelelo ke bothata bjo bogolo kudu go tsa temo/bolemi, segolothata re lebeletse balemirui ba bannyane. Limpopo province e na le kgatelelego ye kgolo kudu ka komelelo gagolo ge re lebeletse tsa bolemi. Nako le nako komelelo e tsea karolo ye kgolo moo e feleletsago e gatelela tsa temo. Tabakgolo ya rena kego lebelela ditsela le mehuta ye e fapanego yeo e shomishitshwego ke balemi go lwantshana le bothata bja komelelo gareng ga ngwaga wa 2014- 2016. Thuto ye e kgobokantshitshwe gotwsa go masepala wa motse selegae wa Greater Letaba Local Municipality, karolo ya Mopani, profenseng ya Leboa mo Afrika Borwa. Tshedimosho ye e hweditshwe ka mokgwa wa poledisano le balemi bao ba fapanego ba go lekana nomoro ya 281 ya balemi go dinaga tsa go fapanafapana. Poledisano ebile ka mokgwa wa peakanyanyo ya dopotsisho. Tshedimosho ye e kopantshitshwe le go hlathollwa ka mokgwa wa go ikgetha wa Strata Version 14. Hlathollo ya go ikgetha e berekishitshwe ka mokgwa wa ditiragalo yoya ka nako le dipalopalo tsa go kopantswa fao tahlegelo e sa tsebjego go ka lekanywa.le bokae la diperesente. Mabakakgolo ao a hlolago tahlegelo ya diruiwa a nyakishitswe ka mokgwa wa Poisson Regression Model. Bogolo bja (64.77%) go bao ba arabilego ebile banna le bogolo bja (74.38%) bja balemi ba be ba tseba ka komelelo ye e batamelago. Go feta halofo (55.50%) ya bao ba arabilegoba tsebishitshwe ka komelelo yeo e batamelang go tswa go bagakolodi, gomme gwa latela thelebisheni (8.13%) le dikuranta (1.44%). Go feta bogolo bja (58.29%) bja bao ba ikarabetsego ba laeditswe gore ba be ba tseba ka komelelo yeo e batamelago ke fao ba bego ba ikemiseditse. Bontshi bja thekgo (80%) yeo balemi ba e hweditsego ebile ka mokgwa wa dijo tsa diphoofolo, gwa latela latela thekgo yeo e filwego ka mokgwa wa meets le dithibela malwetsi go diphoofolo. Bogolo bjago makatsa (73.55%) bo laeditse gore thekgo yeo ba e hweditsego e ba tshwetsi molemo le diphoofolo tsa bona, go feta bonnyane (26.45%) bjoo bo rilego thekgo yeo ba e hweditsegobka nako ya komelelo ga se ya ba tshwela mohola goba gaya ba hola ka selo. Go ba modudi wa Bellevue (B= -0.199; 95% CI: -0.380 -0.019, p= 0.031) le Mokwakwaila (B=0.568; 95% CI: 0.405 0.731, p= 0.0001) ebile nthla ye bohlokwa go tahlegelo ya dirui. Go oketsa seo, go nyadiwa (B=0.942; 95% CI: 0.737 1.201), go hladiwa (B= 0.966 (95% CI: 0.729 1.279), le palo ya mengwaga ya botsebingo tsa temo (B=1.022; 95% CI: 1.010 1.034, p= 0.0001), le ge eba molemi ga se a hwetse thusho ka nako ya komelelo (B=0.324; 95% CI: 0.189 0.459, p= 0.0001) ebile dinhla tsa bohlokwa go tahlegelo ya dirui ka nako ya komelelo. Palo ya fase ba balemi bao ba bego bas a tsebe ka komelelo yeo e bego e batamela, e kgathile tema ye kgolo mo tabeng ya go paledisha balemi go ipeakanyela kgahlanong le komelelo yeo e bego e batamela. Ka fao seo se ba amile gampe. Mo nakong ye e tlang, matsapa a mantsi a swanetswi go tseiwa go kgonthishisha gore tsa temo ka moka di itokishetsa ka go lekana. Mmusho o swanetse go beeletsa kudu go lefapha la bagakolodi ka go oketsa palo ya mafapha a bagakolodi.
Agriculture and Environmental Sciences
M.Sc. (Agriculture)

Physiological characteristics of the response to water stress of two maize cultivars, the one drought resistant (PAN473) and the other drought sensitive (SR52), were compared. Mature plants were grown in one of two treatments, control and water stress. The drought resistant cultivar had a higher growth rate and a greater amount of roots in the lower soil levels than the drought sensitive cultivar in the water stress treatment. There was no difference between the cultivars in physiological characteristics in the control treatment, but in the water-stress treatment the drought resistant cultivar had a higher transpiration rate during the onset of water stress, and higher relative water content and levels of abscisic acid and proline throughout the period of water stress. A comparison between the cultivars in their gene expression response was done to determine if a correlation could be made with the difference in physiological response. A differential screening of water stress cDNA libraries identified nine different cDNA species which gave a signal with the water stress probe but not the control probe. Three of these cDNAs were represented by more than one cDNA clone. The cDNAs occurred in both libraries, therefore there was no difference between the cultivars in the presence or absence of the water stress responsive genes. The three genes represented by these cDNAs were named rws7, rws16 and rws5. All three genes showed increased transcription in response to water stress in whole plants, and to desiccation and osmotic stress of detached leaves. No increase in transcription was found in response to exogenously applied abscisic acid or proline. No difference between the cultivars was observed in the pattern of transcription response. Two of the three cDNA species that are represented more than once were sequenced. Rws7 had an open reading frame. A BLAST search found no homologous amino acid sequences, but the characteristics of the polypeptide suggest that it is a dehydrin. Rws 16 had a partial coding sequence. A BLAST search found two homologous amino acid sequences, and both were chloride channel proteins. The remaining seven cDNA species were sequenced at their 5' ends, and no complete homologous nucleotide sequences were found.
Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1996.

MESHWR
Department of Hydrology and Water Resources
This study dealt with the influence of climate variability on flood and drought cycles and implications on rainy season characteristics in Luvuvhu River Catchment (LRC) in Limpopo of South Africa. Extreme weather events resulting in hazards such as floods and droughts are becoming more frequent due to climate change. Extreme events affect rainy season characteristics and hence have an influence on water availability and agricultural production. Annual temperature was obtained from Water Research Commission for stations 0723485W, 0766628W and 0766898W from 1950-2013 were used to show/or confirm if there is climate variability in LRC. Daily rainfall data was obtained from SAWS for stations 0766596 9, 0766563 1, 0723485 6 and 0766715 5 were used to detect climate variability and determine the onset, duration and cessation of the rainy season. Streamflow data obtained from the Department of Water and Sanitation for stations A9H004, A9H012, and A9H001 for at least a period of 30 years for each station were used for climate variability detection and determination of flood and drought cycles. Influence of climate variability on floods and droughts and rainy season characteristic were determined in the area of study. Trends were evaluated for temperature, rainfall and streamflow data in the area of study using Mann Kendall (MK) and linear regression (LR) methods. MK and LR detected positive trends for temperature (maximum and minimum) and streamflow stations. MK and LR results of rainfall stations showed increasing trends for stations 0766596 9, and 0766563 1 whereas stations 0723485 6 and 0766715 5 showed decreasing trends. Standardized precipitation index (SPI) was used to determine floods and droughts cycles. SPI results have been classified either as moderately, severely and extremely dry or, moderately, very and extremely wet. This SPI analysis provides more details of dominance of distinctive dry or wet conditions for a rainy season at a particular station. Mean onset of rainfall varied from day 255 to 297, with 0766715 5 showing the earliest onset compared to the rest of the stations. Cessation of rainfall for most of the hydrological years was higher than the mean days of 88, 83 and 86 days in 0766596 9, 0766563 1 and 0723485 6 stations. Mean duration of rainfall varied from 102 to 128, with station 0766715 5 showing shortest duration of rainfall. The results of the study showed that the mean onset, duration and cessation were comparable for all stations except 0766715 5 which had lower values. The study also found that climate variability greatly affects onset, duration and cessation of rainfall during dry years. This led to late onset, early cessation and relatively short duration of the rainfall season. Communities within the catchment must be educated to practice activities such as conservation of indigenous plants, reduce carbon dioxide emissions.

A case study on drought coping mechanisms was conducted among small-scale farmers in the Motheo District of the Free State Province in Republic of South Africa, to determine how farmers cope with drought effects with or without external influence in terms of drought relief packages from the government and non-governmental organizations. Data was collected by administering a semi-structured questionnaire to 200 farmers. The data were captured and analysed using SPSS to obtain frequency, cross-tab, univariate ANOVA as well as logistic regression analysis. Findings of the study revealed that only 12.5 percent of the respondents were aware of drought, while a larger percentage of 87.5 of the respondents were not aware of a drought incidence before its onset, which made them more vulnerable to the drought disaster; 8.5 percent of them protected water sources for livestock while 91.5 percent of the farmers did not protect water sources for their livestock because they farm on a communal land; 42.5 percent provided supplementary feeds to livestock during the drought, but 57.5 percent did not provide supplementary feed for their animals for lack of funds. Ninety-nine (99.0) percent of the respondents shared grazing lands while only 1 per cent did not because most farmers operates on a communal system of farming; 35.5 percent changed cropping systems; 50.5 percent had alternative water sources for crops which included mini and hand irrigation systems while 49.5 percent of the respondents depended solely on streams and rivers available in the villages; 19.3 percent sold or pledged assets in order to be able to cope with drought effects while most farmers did not pledge or sell assets not because they did not want to, but because they did not have assets to sell.
Envornmental Science
Thesis (M.Sc. (Environmental Management))

This thesis seeks to explore and examine the application and use of indigenous knowledge systems (IKS) in the management of drought through a case study of Msinga village communities in the northern parts of KwaZulu-Natal Province, paying specific attention to droughts that have been recorded and that prevail in the area. Government's policy aimed at mitigating and the effect of drought on communities and its effectiveness is examined as well. The question is whether government policy measures supplement rural communities' drought management strategies. The findings demonstrated that droughts are endemic in the study area and that drought-management strategies are as intrinsic to local livelihood systems as are seasonal-adjustment strategies. The findings also indicated that communities in Msinga have knowledge of drought management. However, this knowledge contributes very little to the management of drought. The findings also demonstrated that there is poor capacity in government to deal with disasters and this has serious repercussions for poor rural communities in Msinga. Disaster management requires disaster reduction, planning, and capacity to reduce the losses borne by impoverished households. This process will be more effective if there is efficient mobilization of resources, rapid responses, and a long-term strategy to prevent drought and reduce the risks of vulnerable groups, rather than transferring risks. The new legislation, the Disaster Management Act of 2002, should ensure that any form of financial and bureaucratic bottlenecks are eliminated so that assistance reaches people more quickly and is based on developing a long-term programme targeting the reduction of risks from the drought prevailing in Msinga. It is also important that NGOs in the area are empowered and involved in disaster management and are able to play their full role.
Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2010.

South Africa is classified as a semi-arid environment with limited natural water sources. Amenity landscapes provide broad ranging benefits for society. Amenity landscapes account for between 31% - 50% of water supplied for domestic and urban use. To reduce water use and water conservation in amenity landscapes, strategies, regulations and interventions are required. Every landscape is a unique complex system with a large number of variables that differ from each other. The variability can be summarized into management/design, irrigation, climatological, edaphic and plant related aspects. Several amenity landscape water use models have been developed around the world and two in South Africa. This study developed a comprehensive South African hydrozone based plant database and an Amenity Landscape Water Use Model South Africa (ALWUMSA). This will improve hydrozoning of amaneity landscapes and ultimately also improve water conserbvation for these sites. It allows users/owners to determine water use requirements through an extensive data gathering, from aspects such as design, management, microclimate, environmental, edaphic, irrigation and plant related factors. Comparisons of results from ALWUMSA to three test sites, selected existing models and a range of scenarios produced results demonstrating that ALWUMSA consistently projected lower water requirements. The model also allows for site aspects to be changed thus encouraging end users to implement specific water saving intiatives with the amenity landscape to reduce water use. These savings will be translated into both water-use savings as well as financial savings for users of the amenity landscape water use model.
Environmental Sciences
Ph. D. (Environmental Science)

Sweetpotato (Ipomoea batatas) is a major staple food in Africa and the rest of the world where they are discovered to be a good source of carbohydrates, vitamin A, vitamin C and protein. The maximum production potential of the crop is being hampered by severe drought which ravages most parts of Africa. The main aim of this project therefore is to screen collected accessions of sweetpotatofor drought tolerance in a quick screening method with a view to identify cultivars that can perform well under water stress conditions. Fifty selected sweetpotato accessions consisting of cultivars and breeding lines collected from the ARC-VOPI gene bank were planted for drought screening in the glass house for 6 weeks during which water was withheld to induce stress. Observations were made on number of dead plants and days to wilting point, the results were analyzed and 12 best performing cultivars were selected for field trials. The field trial was carried out in Lwamondo, Thohoyandou for 6months under rain-fed conditions. The experiment was conducted in a complete randomized block design with 6 replicates.Yield data and growth parameters were collected every 8 weeks during the trial period and the data collected was analyzed using ANOVA. The best performing cultivars were Zapallo, Tacna, Ejumula, 2004-9-2 and Ndou. They were therefore recommended for further evaluation in other drought prone areas of the country.
Agriculture and  Animal Health
M. Sc. (Agriculture)

Student Number : 0414810F - MA research report - School of Social Sciences - Faculty of Humanities
The goal of this research report was to profile the coping strategies of households in Thorndale to the effects and impacts of the 2002/2003 drought. Thorndale, the study site is prone to drought and thus experiences severe drought almost every year. The rationale behind the selection of Thorndale for the study was based on this fact, in addition to the fact that the study area is relatively unstudied. The study’s major findings included inadequate agricultural extension service delivery in the community, while the drought’s impacts were economic, social, nutritional and health, food shortage, environmental and wildlife. The most significant and largest impact was water shortage. These impacts led to increased household dependency on the natural capital component of livelihoods in addition to prostitution and the community’s institutional arrangements. The main constraints households encountered in response to the drought’s impacts included the lack of employment opportunities, financial and infrastructural problems among others. It is recommended that with respect to food security, efforts should be made to ensure the trickle down effect of national level assessment of vulnerability on annual basis to rural households in South Africa’s drought-prone areas including Thorndale, in order to improve timely and practical solutions to issues of food insecurity. Furthermore, it should be ensured that the national level benefits of early warning systems trickle down to the local and community levels including Thorndale. Additionally, agricultural extension service delivery in the community needs to be improved.

Sunflower (Helianthus annuus L.) is one of the most important oil crops in South Africa and genetic improvement for grain yield and oil-content was initiated in the country in the early 1970s. Commercial production of sunflower in South Africa is done under natural rainfall conditions in areas where frequencies of drought are high hence the requirement for drought tolerant cultivars. An assessment of the genetic gains in seed and oil yield achieved since 1970, the effects of re-cycling inbred lines and strategies for developing drought tolerant sunflower cultivars has not been done for South African sunflower breeding programmes. Two data-sets were used for the genetic gain studies: side-by-side evaluation of historical and current sets of popular cultivars in the same environment under one set of trial management practices; and yield trends in commercial farmers’ fields based on annual production estimates. The estimated relative genetic gain for seed yield based on side-by-side trials was 1.5% year−1 and the relative gain in seed yield per year under commercial production was 1.9% year−1. The contribution of new cultivars to total seed yield progress in sunflower were 56.3% for the period 1970 to 1989; 23.9% from 1990 to 2009 and the mean over the four decades under consideration from 1970 to 2009 was 41.6%. Quantifying the usefulness of inbred lines in advanced cycle plant breeding was done using four base breeding populations based on: phenotypic or genetic variability; heterosis; and combining ability. Significant genetic variation was evident for seed yield and oil yield while genetic variability for oil content was low. Genetic advance (GA%), with a 10% selection intensity, was high for seed yield and oil yield for each of the four populations ranging from 36-42% and 38-43%, respectively. The GA% for oil content was low ranging from 1.3% to 5.1% indicating the need to introgress high oil content germplasm in the present breeding populations in advanced cycle pedigree breeding. Founder parent heterosis (FPH), mid-standard heterosis (MSH) and high standard heterosis (HSH) indicated that some new testcross hybrids from the advanced cycle pedigree breeding populations were performing better than their founder parents in hybrid combination as well as the standard commercial hybrid checks. From variance component analysis, general combining ability (GCA) was predominant over specific combining ability (SCA) for seed and oil yields indicating that superior hybrids can be identified based on positive and significant GCA effects of the female lines. For oil content, SCA was predominant over GCA indicating that it would be best to select for specific hybrids combinations with high oil content rather than selecting female lines with high GCA effects. Variable moisture conditions characterise the sunflower production environments in South Africa. Breeding for such environmental conditions requires a combination of strategies including use of secondary traits and developing appropriate test environments. Three secondary traits, head diameter, stem diameter and stay green canopy which are easy to measure in the field were evaluated for their appropriateness for selecting for drought tolerance under three moisture conditions: random stress environments (RSE), managed drought stress environments (MSE) and well watered nonstress environments (NSE). Type A genetic correlations indicated that stay green canopy (SG) had the potential to be used as secondary trait to indirectly improve oil yield under the three moisture conditions. The indirect selection efficiency (ISE) for SG using genetic correlations based on H2 were 0.79, 0.82 and 0.78 in the RSE, MSE and NSE, respectively, while that using genetic correlation based on h2 were 0.67, 0.98, and 0.93 in the RSE, MSE and NSE, respectively. In both cases selection in the MSE had the highest efficiency using genetic correlations based on either H2 or h2. Estimates of indirect selection based on type B genetic correlations indicated that indirect selection for oil yield (OY) in the MSE and NSE for the target RSE was as effective as direct selection of OY in the RSE based on additive genetic correlations of 0.96 obtained in both selection environments. Overall, the results from the exploratory drought tolerance study should inform the development of breeding strategies to improve drought tolerance and associated yield stability of sunflower cultivars grown in South Africa and associated environments.
Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.

Cowpea (Vigna unguiculata (L.) Walp) is an important protein-rich grain legume of major economic importance. It is widely grown by small-scale farmers in the arid and semi-arid regions of the world where it is cultivated for its leaves, fresh immature pods and dry grains. However, it is also an underutilized grain legume. In sub-Saharan Africa where most of the cowpea is produced, drought stress is one of the major factors limiting its productivity. Despite the inherent capacity to survive drought stress, several cowpea varieties are affected by mid and late season drought. Therefore, varieties with a higher tolerance to drought stress are required to obtain higher and more stable yields. The objectives of this study were: (i) to determine morphological responses of four dual-purpose cowpea landraces to water deficits during vegetative and reproductive stages (ii) to determine physiological responses of four dual-purpose cowpea landraces to water deficits and recovery during the reproductive stage (iii) to determine yield performance of cowpea landraces after recovery from water stress and how this relates to (ii) above. Four cowpea landraces namely; Lebudu, Lehlodi, Sejwaleng and Morathathane collectedfrom Kgohloane and Ga-Mphela villages, Limpopo Province, South Africa were used in the study. Pot experiments were conducted under glasshouse conditions at the Controlled Environment Facility (CEF), University of KwaZulu-Natal. The first pot experiment evaluated the morphological responses of four cowpea landraces to water stress and recovery. The study was conducted as a single factor experiment laid out in randomized complete block design (RCBD). The treatments (four cowpea landraces) were each planted in 40 pots giving a total of 160 experimental units (drained polyethylene pots with a 5 litre capacity). Each plant in each pot was treated as a replicate. Plants were well-watered until the formation of six fully expanded trifoliates, then irrigation was withheld for 28 days to simulate drought stress during the vegetative growth. The imposition of drought stress was terminated by re-watering all plants after 28 days. The cowpea plants were re-watered sufficiently and allowed to grow until the four landraces reached 50% flowering stage. Watering was withheld again at 50% flowering for a two-week period for all the four landraces to simulate drought stress during the reproductive growth. The second experiment was conducted to investigate physiological responses of the four cowpea landraces to water stress during the reproductive stage. The experiment was laid out as a 4 x 2 factorial treatment structure in randomized complete design (CRD) with the following three factors: cowpea landraces – 4 levels (Lebudu, Lehlodi, Sejwaleng and Morathathane), water regimes – 2 levels (stressed and well-watered) treatment combinations each replicated 20 times (20 pots each containing one plant) giving a total of 160 experimental units (drained polyethylene pots with a 5 litre capacity). Data on morphological responses were collected and included: number of green vs. senesced leaves, visual assessment of leaf greenness, stem, branch greenness and survival percentage. Physiological responses to water stress were determined during the reproductive stage and included: leaf water potential, relative water content, stomatal conductance, proline content, chlorophyll content, carotenoid content, chlorophyll a content, phenolics (free and membrane-bound), total antioxidant capacity and chlorophyll fluorescence parameters (Fv/Fm). Genstat 14th edition (VSN International, UK) was used to perform analyses of variance (ANOVA) and differences between means were determined by the Least Significant Differences (LSD) at the 5% probability level. Landraces showed different morphological responses during both vegetative and reproductive growth stages. Lebudu, Lehlodi and Sejwaleng displayed a strong ability to maintain stem greenness longer as compared to Morathathane during vegetative growth. Lebudu delayed leaf senescence more than other landraces; no differences in survival were observed. All landraces survived for 28 days without water and resumed growth after re-watering. During the reproductive stage, Lebudu displayed a strong ability to maintain leaf, branches and stem greenness longer and showed relatively higher tolerance to drought stress compared to other three landraces. Water stress caused a decline in leaf water potential, relative water content, carotenoid content, chlorophyll content, stomatal conductance and increased proline content, phenolics, chlorophyll a content, total antioxidant capacity and while chlorophyll fluorescence parameter, Fv/Fm, was not affected. All landraces maintained higher relative water content above a critical threshold with Sejwaleng maintaining a significantly higher RWC (69%) than Lehlodi, Lebudu and Morathathane. Morathathane developed a more negative leaf water potential at maximum stress than Lebudu, Lehlodi and Sejwaleng. Stomatal closure was observed in all cowpea landraces during water stress, but re-opened after re-watering. Chlorophyll content was considerably reduced in Morathathane as compared to Lebudu, Lehlodi and Sejwaleng. No significant differences were observed between the cowpea landraces with respect to carotenoid content at maximum stress. Chlorophyll a content increased significantly for Morathathane as compared to Lebudu, Lehlodi and Sejwaleng. High accumulation of proline was observed for Lebudu, Lehlodi and Morathathane as compared to Sejwaleng, which showed a very slow accumulation of proline. Lebudu, Lehlodi and Sejwaleng showed an increase in phenolic compounds while a decline was observed for Morathathane. Total antioxidant capacity (TAOC) was high in all cowpea landraces during water stress. Also, all chlorophyll fluorescence parameters showed that cowpea landraces had efficient photo-protection mechanisms during drought stress. After re-watering, relative water content, leaf water potential, stomatal conductance, chlorophyll content, carotenoids, chlorophyll a, proline content and TAOC recovered and reached the same level as that of well-watered plants. All four landraces were re-watered after the imposition of stress and above ground biomass, pod mass and number and seed yield determined. Although there was a reduction in the total above-ground biomass, pod mass and number in all four landraces under water stress compared to the well–watered treatment; this was not statistically significant (P > 0.05). Furthermore, no significant differences (P > 0.05) were observed between the four landraces with respect to seed yield under stressed and well-watered conditions. This study established that cowpea landraces vary with respect to the various morphological and physiological adaptive mechanisms in response to water deficits. Such adaptive mechanisms probably ensure their survival under severe water stress conditions until the next rainfall and therefore allowing them to produce reasonably relatively higher leaf and seed yield. Detailed knowledge of these mechanisms in the landraces could be useful in the genetic enhancement and breeding for drought tolerance in the existing cowpea germplasm.
Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.

Recurring drought conditions have always been an endemic feature of climate in South Africa, limiting maize development and production. However, recent projections of the future climate by the Intergovernmental Panel on Climate Change suggest that due to an increase of atmospheric greenhouse gases, the frequency and severity of droughts will increase in drought-prone areas, mostly in subtropical climates. This has raised major concern for the agricultural sector, particularly the vulnerable small-scale farmers who merely rely on rain for crop production. Farmers in the Luvuvhu River catchment are not an exception, as this area is considered economically poor, whereby a significant number of people are dependent on rain-fed farming for subsistence. This study was therefore conducted in order to improve agricultural productivity in the area and thus help in the development of measures to secure livelihoods of those vulnerable small-scale farmers. Two drought indices viz. Standardized Precipitation Evapotranspiration Index (SPEI) and Water Requirement Satisfaction Index (WRSI) were used to quantify drought. A 120-day maturing maize crop was considered and three consecutive planting dates were staggered based on the average start of the rainy season. Frequencies and probabilities during each growing stage of maize were calculated based on the results of the two indices. Temporal variations of drought severity from 1975 to 2015 were evaluated and trends were analyzed using the non-parametric Spearman’s Rank Correlation test at α (0.05) significance level. For assessing climate change impact on droughts, SPEI and WRSI were computed using an output from downscaled projections of CSIRO Mark3.5 under the SRES A2 emission scenario for the period 1980/81 – 2099/100. The frequency of drought was calculated and the difference of SPEI and WRSI means between future climate periods and the base period were assessed using the independent t-test at α (0.10) significance level in STATISTICA software. The study revealed that planting a 120-day maturing maize crop in December would pose a high risk of frequent severe-extreme droughts during the flowering to the grain-filling stage at Levubu, Lwamondo, Thohoyandou, and Tshiombo; while planting in October could place crops at a lower risk of reduced yield and even total crop failure. In contrast, stations located in the low-lying plains of the catchment (Punda Maria, Sigonde, and Pafuri) were exposed to frequent moderate droughts following planting in October, with favorable conditions noted following the December planting date. Further analysis on the performance of the crop under various drought conditions revealed that WRSI values corresponding to more intense drought conditions were detected during the December planting date for all stations. Moreover, at Punda Maria, Sigonde and Pafuri, it was observed that extreme drought (WRSI <50) occurred once in five seasons, regardless of the planting date. Temporal analysis on historical droughts in the area indicated that there had been eight agricultural seasons subjected to extreme widespread droughts resulting in total crop failure i.e. 1983/84, 1988/89, 1991/92, 1993/94, 2001/02, 2002/03, 2004/05 and 2014/15. Results of Spearman’s rank correlation test revealed weak increasing drought trends at Thohoyandou (ρ = of 0.5 for WRSI) and at Levubu and Lwamondo (ρ = of 0.4 for SPEI), with no significant trends at the other stations. The study further revealed that climate change would enhance the severity of drought across the catchment. This was statistically significant (at 10% significance level) for the near-future and intermediate-future climates, relative to the base period. Drought remains a threat to rain-fed maize production in the Luvuvhu River catchment area of South Africa. In order to mitigate the possible effects of droughts under climate change, optimal planting dates were recommended for each region. The use of seasonal forecasts during drought seasons would also be useful for local rain-fed maize growers especially in regions where moisture is available for a short period during the growing season. It was further recommended that the Government ensure proper support such as effective early warning systems and inputs to the farmers. Moreover, essential communication between scientists, decision makers, and the farmers can help in planning and decision making ahead of and during the occurrence of droughts.
Agriculture, Animal Health and Human Ecology
M. Sc. (Agriculture)

MSCAGR (Plant Production)
Department of Plant Production
Chickpea (Cicer arietinum L.) is an excellent utilizer of residual soil moisture in agricultural ecosystems. However, its seed quality and hence reproduction is constrained by water stress, seed size and storage conditions. This study was carried out at the University of KwaZulu- Natal (UKZN), Pietermaritzburg Campus. It was conducted to evaluate the performance of chickpea genotypes (Desi-K, Saina-K and ICCV-K) with different seed sizes on seedling emergence (i), seed ageing effect on seed quality and imbibition of genotypes produced under water stressed and non-stressed conditions (ii), and (iii) the effect of water stress during seed development on sugars and protein accumulation, germination and seed vigour. Pot experiments were conducted under glasshouse / tunnel conditions at the Controlled Environment Facilities (CEF). The experiment for objective 1 was laid out as a single factor in completely randomized design (CRD). Data on emergence rate, final hypocotyl and complete emergence was collected. The small seeded Desi-K showed higher and faster emergence compared to medium sized Saina-K and large seeded ICCV-K. In the experiment of the second objective, seeds of the three genotypes were first obtained by production under water stressed and non-stressed growing conditions. They were then aged for 0, 1, 3, 5, or 7 days at 41 ºC and 100% relative humidity to form a 2 x 3 x 5 (water levels x genotypes x ageing) factorial design. Data was collected on germination percentage (GP), mean germination time (MGT), electrical conductivity (EC), tetrazolium chloride test (TZ) and imbibition weight. Seed ageing caused progressive loss of seed viability and vigour in all genotypes, which resulted in lower GP, delayed MGT, reduced TZ staining, cell death and high solute leakage from the seeds produced under the two water regimes. However, the effect was more severe under water stressed conditions. In the experiment for objective 3, seeds of all three genotypes were larger when grown under non-stressed condition compared to those under water stressed condition. These larger seeds had higher seed viability and germination percentage but lower electrical conductivity and mean germination time. Stressed seeds had higher soluble sugars than non-stressed seeds. It was deduced that irrigation during seed development reduces the final sugars and protein content but increases the seed size and physiological quality parameters allied to production of chickpea. Therefore, water provision to chickpea crop is critical during seed development.
NRF

Water is a symbol of life. It affects all organisms on earth and its importance is emphasised in times of drought. The human population growth places more demands on our natural resources. As pressures on the available water increases, more measures are required to utilise water sustainably. South Africa is classified as a water stressed country with less than 1700 cubic meters of water available per person per year. Rand Water supplies water to approximately 11 million people in Gauteng. During times of drought, restrictions imposed are aimed mainly at the broader Green Industry. This research investigated international strategies, existing restrictions in Gauteng, and undertook a survey within the Green Industry to determine the most appropriate response. This research proposes a new water supply shortage response plan for Rand Water in Gauteng with a total of four levels of restrictions implemented at different stages of water stress in the system.
Environmental Sciences
M. Sc. (Environmental Management)

Climate change and variability have great impact on the hydrological cycle and consequently on the availability of water resources. Variations in temperature and precipitation trends that are occurring are a consequent of the increase in the concentrations of greenhouse gases, which are subsequently affecting the hydrological cycle. This in turn affects water quantity and quality, which is essential for agriculture, domestic and industrial uses. This study, done in Elliot Town and the surrounding areas of Sakhisizwe Municipality in the Eastern Cape Province of South Africa, evaluates how climate change and variability is affecting water availability and its quality in the town. The impact climate change and variability on agricultural production is also assessed. Remote Sensing, Geographic Information Systems (GIS), databases and some statistical packages have been used to collect, analyse and create spatial maps used to derive concrete conclusions. The methods used aided in spatially analysing the changes in temperature and rainfall along the years and make a comparative analysis. The study has shown that the spatial changes in the amount, intensity and frequency of rainfall affects the magnitude and frequency of stream flows; consequently, increasing the intensity of floods and droughts that have been recurring in the last few decades. The municipality is more affected by climate variability than change, and the resultant extreme climate events are affecting the water resources resulting in domestic water cuts, poor water quality and low agriculture productivity. This study recommends the importance of an awareness campaigns on climate change and variability and their effect directed towards the community, especially on novel water harvesting technologies. The study also highlights the importance of a robust early warning system to prepare the community in case of a climate shock, which is an area that needs further research.
Environmental Sciences

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. Johannesburg, 2016.
The drought-stricken, eastern Kalahari region of South Africa is a water stressed region that is solely dependent on groundwater for its water supply. This resource is of primary importance in supplying safe drinking water to the inhabitants of both the towns and rural areas within this region, there being no other alternative. This situation can prove precarious, as the poorly understood complexities of the nature and behaviour of groundwater in this region has often led to over utilisation of the resource in some parts. The efficient and sustainable use of groundwater is paramount to ensure the sustainable and equitable development of the region. As such, an attempt was made to contribute to the understanding of the groundwater potential of this region by examining a number of the hydrogeological factors at play. The total resource potential for the entire study area is estimated at 10,127.29 x 106 m3/a, with the Kalahari aquifer showing the greatest potential in the study area, comprising 50.67 % of the total resource. The storage capability of the Kalahari aquifer (5478.52 x 106 m3) is also impressive, estimated to be more than twice that of the dolomite (2727.99 x 106 m3). This significant storage space of the Kalahari aquifer can allow groundwater recharge to be stored for several decades or even millennia, thereby providing a vital buffer against climate variability. Despite having such great potential, the aquifer is not actively recharged and is often associated with very saline water that is not suitable for human and livestock consumption. As such, although showing the most potential for storage, exploitation of this resource is restricted. The limestones and dolomites of the Campbell Rand and Schmidtsdrif Subgroups are considered as the most prospective water bearing formations in the study area, largely owing to weathering and karstification processes that have made them prolific aquifers and have aided significantly in their resource potential estimated at approximately 1980.65 x 106 m3/a. Although this area shows potential for higher yielding boreholes (> 5 l/s), this particular aquifer does not display hydraulic continuity, with poor water exchange between compartments, resulting in variations in yield and the amount of recharge available. Unlike the Kalahari, these aquifers cannot sustain abstraction through periods of drought, there being no natural regulation to their outflow, as such, caution has to be exercised over how much of the groundwater can in fact be abstracted from this aquifer. The weathered granitic rocks of the Archaean basement within the south-central portion of the study area show favourable resource potential (1844.71 x 106 m3/a) and are typically associated with the better quality groundwater in the study area. The groundwater has moderate salinity and is not as “hard” as the water associated with the karstic and Kalahari aquifers. Unfortunately, however, it is this aquifer that is commonly exploited, particularly for intensive irrigated agriculture. Although isotopic evidence suggests the presence of recent recharge, this aquifer receives most of its recharge from the outcropping areas of the aquifer, with the remaining 70 % of the area being overlain by thick deposits (> 15 m) of Kalahari sediment, which retain a large amount of the recharge from where it is lost by evapotranspiration. As such, if this aquifer is to be utilised sustainably and its use ensured for future generations, stricter controls need to be placed on the volume of water abstracted, particularly by irrigated agriculture. Aquifers with the least potential in the study area generally comprise the fractured basement rocks of the Kraaipan - Amalia greenstone belt, with a resource potential of 26.45 x 106 m3/a, and the fractured sedimentary rocks of the Asbestos Hills Subgroup, with a resource potential of 108.33 x 106 m3/a. While these aquifers offer poor prospects of securing large volumes of groundwater, with the groundwater being primarily confined to their fracture systems, these aquifers offer some of the best recharge areas within the study area. Their isotopic signature seems to suggest that recharge is taking place from the surrounding high ground, where surface and structural controls are responsible for the regional hydraulic continuity. Under favourable conditions, these aquifers may also recharge the adjacent karstic and granitic aquifers, where local structures enable limited lateral and vertical displacement. Overall, the calculated groundwater storage and resource potential within the study area satisfies a large proportion of the water demand in the eastern Kalahari region of South Africa. If each aquifer could be sustainably utilised, a considerable volume of water could be abstracted at an assurance of supply similar to that of surface water. The emphasis, however, is placed on “sustainable exploitation”, as groundwater in this region is also vulnerable to quality degradation and over-exploitation. This often stems from the poorly understood nature of groundwater and the hydrogeological factors at play in the region. The key challenge, therefore, relates to the effective management of the resource, with all role players involved in this complex system working together to achieve the goal of maintaining the quality of the water and ensuring that it is used sustainably, protecting it for future generations.
LG2017

Droughts can have serious ecological and economic consequences and will pose an increasing challenge to rangeiand users as the global climate is changing. Finding ways to reduce ecological and economic impacts of drought should thus be a major research thrust. Resilience, defined as the amount of perturbation a social or ecological system can absorb without shifting to a qualitatively different state, has emerged as a prominent concept in ecosystem ecology and more recently as a conceptual framework for understanding and managing complex social-ecological systems. This paper discusses the application and relevance of resilience to understanding and managing ecosystem change, and enhancing the capacity of land users to adapt to droughts. Drought can trigger vegetation change and factors such as grazing management can influence the likelihood of such transitions. Drought can cause differential mortality of perennial plants and this could provide an opportunity for rangeland restoration by opening up establishment sites for desirable species. The capacity of land users to cope with drought is influenced by the resilience of their agro-ecosystems, the diversity of livelihood options, access to resources and institutional support. By these criteria, current agricultural development approaches in South Africa, particularly in communal rangelands and areas of land reform, are unlikely to enhance land users' resilience to drought and other perturbations.

MENVSC
Department of Geography and Geo-Information Sciences
Climate change has a crucial impact on livelihoods, economy, and water resources due to the occurrence of weather and climate extreme events such as floods, droughts and heat waves. Extreme weather has been increasing worldwide, hence the need to understand their nature and trends. The aim of this study was to analyse the spatial variability and long-term trends of climate extremes over the Limpopo in South Africa from 1960 to 2014. Rainfall, temperature, and circulation fields were analysed to understand the extent, nature of climate extremes over the Limpopo. Extreme value theory (EVT) is a powerful method that was also employed in this study to provide statistical models for events rarely observed. R statistical software was used for clustering analysis which has a variety of functions for cluster analysis. Any station whose value is larger than 95th for any day of the season was considered as a widespread extreme event. The results show that the study area is highly vulnerable to extreme events due to its latitudinal location and low altitude. Anomalous cut-off lows, tropical cyclones and tropical storms are the major extreme producing systems affecting the Limpopo province whilst the Botswana High becomes dominant during heat waves and drought. Extreme weather events are common in Limpopo during summertime and often coincide with mature phases of the El Nino Southern Oscillation. In this study, after the suitable model for data was chosen, the interest was in deriving return levels of extreme maximum rainfall. The computed data for return levels predicted that the 5-year return period’s return level is approximately 223.89 mm, which suggests that rainfall of 223.89 mm or more per month should occur at that station or location on the average of once every five years.
NRF
http://hdl.handle.net/11602/1485

Issues surrounding water scarcity will become topical in future as global fresh water resources become more limited thus threaten crop production. Predicted climate change and increasing population growth will place more pressure on agriculture to produce more food using less water. As such, efforts have now shifted to identifying previously neglected underutilised species (NUS) as possible crops that could be used to bridge the food gap in future. Taro (Colocasia esculenta L. Schott) and bambara groundnut (Vigna subterranea L. Verdc) currently occupy low levels of utilisation in South Africa. Both crops are cultivated using landraces with no improved varieties available. Information describing their agronomy and water–use is limited and remains a bottleneck to their promotion. The aim of this study was to determine the drought tolerance and water–use of selected landraces of taro and bambara groundnut from KwaZulu-Natal, South Africa. In order to meet the specific objectives for taro and bambara groundnut management, an approach involving conventional and modelling techniques was used. Three taro landraces [Dumbe Lomfula (DL), KwaNgwanase (KW) and Umbumbulu (UM)] were collected from the North Coast and midlands of KwaZulu-Natal, South Africa, in 2010. The UM landrace was classified as Eddoe type taro (C. esculenta var. antiquorum) characterised by a central corm and edible side cormels. The DL and KW landraces were classified as Dasheen (C. esculenta var. esculenta), characterised by a large edible main corm and smaller side cormels. A bambara groundnut landrace was collected from Jozini, KwaZulu- Natal, and characterised into three selections (‘Red’, ‘Light-brown’ and ‘Brown’) based on seed coat colour. Seed colour was hypothesised to have an effect on seed quality. Field and rainshelter experiments were conducted for both taro and bambara landraces at Roodeplaat in Pretoria and Ukulinga Research Farm in Pietermaritzburg, over two growing seasons (2010/11 and 2011/12). The objective of the field trials for taro and bambara groundnut was to determine mechanisms associated with drought tolerance in taro and bambara groundnut landraces. Experiments were laid out in a split-plot design where irrigation [fully irrigated (FI) and rainfed (RF)] was the main factor and landraces (3 landraces of either taro or bambara groundnut) were sub-factors. Treatments were arranged in a randomised complete block design (RCBD), replicated three times. Rainfed trials were established with irrigation to allow for maximum crop stand. Thereafter, irrigation was withdrawn. Whilst experimental designs and layouts for taro and bambara groundnut were similar, differences existed with regards to plot sizes and plant spacing. Trials were planted on a total land area of 500 m2 and 144 m2, for taro and bambara groundnut, respectively. Plant spacing was 1 m x 1 m for taro and 0.3 m x 0.3 m for bambara groundnut. Irrigation scheduling in the FI treatment was based on ETo and Kc and was applied using sprinkler irrigation system. Separate rainshelter experiments were conducted for taro and bambara groundnut landraces at Roodeplaat, to evaluate growth, yield and water-use of taro and bambara groundnut landraces under a range of water regimes. The experimental design was similar for both crops, a RCBD with two treatment factors: irrigation level [30, 60 and 100% crop water requirement (ETa)] and landrace (3 landraces), replicated three times. Irrigation water was applied using drip irrigation system based on ETo and Kc. Data collection in field and rainshelter trials included time to emergence, plant height, leaf number, leaf area index (LAI), stomatal conductance and chlorophyll content index (CCI). For taro field trials, vegetative growth index (VGI) was also determined. Yield and yield components (harvest index, biomass, corm number and mass) as well as water–use efficiency (WUE) were determined at harvest. Intercropping of taro and bambara groundnut was evaluated under dryland conditions using farmers’ fields at Umbumbulu, KwaZulu–Natal, South Africa. The experimental design was a RCBD replicated three times. Intercrop combinations included taro and bambara groundnut sole crops, a 1:1 (one row taro to one row bambara groundnut) and 1:2 intercrop combinations. The taro UM landrace and ‘Red’ bambara groundnut landrace selection were used in the intercropping study. Lastly, data collected from field and rainshelter experiments were used to develop crop parameters to calibrate and validate the FAO’s AquaCrop model for taro and bambara groundnut landraces. The UM landrace was used for taro while the ‘Red’ landrace selection was used for bambara groundnut. AquaCrop was calibrated using observed data from optimum (FI) experiments conducted during 2010/11. Model validation was done using observations from field and rainshelter experiments conducted during 2011/12 as well as independent data. Results showed that all taro landraces were slow to emerge (≈ 49 days after planting). Stomatal conductance declined under conditions of limited water availability (RF, 60% and 30% ETa). The UM landrace showed better stomatal regulation compared with KW and DL landraces under conditions of limited water availability. Plant growth (plant height, leaf number, LAI and CCI) of taro landraces was lower under conditions of limited water availability (RF, 60% and 30% ETa) relative to optimum conditions (FI and 100% ETa). The UM landrace showed moderate reductions in growth compared with the DL and KW landraces, suggesting greater adaptability to water limited conditions. The VGI showed a large reduction in growth under RF conditions and confirmed the UM landrace’s adaptability to limited water availability. Limited water availability (RF, 60% and 30% ETa) resulted in lower biomass, HI, and final yield in taro landraces relative to optimum conditions (FI and 100% ETa). For all trials, the DL landrace failed to produce any yield. WUE of taro landraces was consistent for the three irrigation levels (30, 60 and 100% ETa); however, on average, the UM landrace was shown to have a higher WUE than the KW landrace. Bambara groundnut landraces were slow to emerge (up to 35 days after planting). ‘Red’ and ‘Brown’ landrace selections emerged better than the ‘Light-brown’ landrace selection, confirming the effect of seed colour on early establishment performance. Plant growth (stomatal conductance, CCI, plant height, leaf number, LAI and biomass accumulation) was lower under conditions of limited water availability (RF, 60% and 30% ETa) relative to optimum conditions (FI and 100% ETa). The ‘Red’ landrace selection showed better adaptation to stress. Limited water availability resulted in early flowering and reduced flowering duration as well as early senescence and maturity of bambara groundnut landrace selections. The ‘Red’ landrace selection showed delayed leaf senescence under conditions of limited water availability. Yield reductions of up to 50% were observed under water limited conditions (RF, 60% and 30% ETa) relative to optimum conditions (FI and 100% ETa). Water use efficiency increased at 60% and 30% ETa, respectively, relative to 100% ETa, implying adaptability to limited water availability. The ‘Red’ landrace selection showed better yield stability and WUE compared with the ‘Brown’ and ‘Light-brown’ landrace selections suggesting that seed colour may be used as a selection criterion for drought tolerance in bambara groundnut landraces. The intercropping study showed that intercropping, as an alternative cropping system, had more potential than monocropping. Evaluation of growth parameters showed that taro plant height was generally unaffected by intercropping but lower leaf number was observed as compared with the sole crop. Bambara groundnut plants were taller and had more leaves under intercropping relative to the sole crop. Although not statistically significant, yield was generally lower in the intercrops compared with the sole crops. Evaluation of intercrop productivity using the land equivalent ratio (LER) showed that intercropping taro and bambara groundnut at a ratio of 1:1 was more productive (LER = 1.53) than intercropping at a ratio of 1:2 (LER = 1.23). The FAO’s AquaCrop model was then calibrated for the taro UM landrace and ‘Red’ bambara groundnut landrace selection. This was based on observations from previous experiments that suggested them to be drought tolerant and stable. Calibration results for taro and bambara groundnut landraces showed an excellent fit between predicted and observed parameters for canopy cover (CC), biomass and yield. Model validation for bambara groundnut showed good model performance under field (FI and RF) conditions. Model performance was satisfactory for rainshelters. Validation results for taro showed good model performance under all conditions (field and rainshelters), although the model over-estimated CC for the declining stage of canopy growth under RF conditions. Model verification using independent data for taro showed equally good model performance. In conclusion, the taro UM landrace and ‘Red’ bambara groundnut landrace selection were shown to be drought tolerant and adapted to low levels of water–use. The mechanisms responsible for drought tolerance in the taro UM landrace and ‘Red’ bambara groundnut landrace selection were described as drought avoidance and escape. The taro UM landrace and ‘Red’ bambara groundnut landraces avoided stress through stomatal regulation, energy dissipation (loss of chlorophyll) as well as reducing canopy size (plant height, leaf number and LAI), which translates to minimised transpirational water losses. This indicated landrace adaptability to low levels of water–use. The ‘Red’ bambara groundnut landrace selection showed phenological plasticity and escaped drought by flowering early, delaying leaf senescence, and maturing early under conditions of limited water availability. Performance of the ‘Red’ landrace selection lends credence to the use of seed coat colour as a possible selection criterion for drought tolerance in bambara groundnut, and possibly for other landraces with variegated seed. The taro UM landrace escaped drought by maturing early under conditions of limited water availability. The FAO’s AquaCrop model was successfully calibrated and validated for taro UM and ‘Red’ bambara groundnut landraces. The calibration and validation of AquaCrop for taro is the first such attempt and represents progress in the modelling of neglected underutilised crops. The calibration and validation of AquaCrop for taro requires further fine-tuning while that for bambara groundnut still needs to be tested for more diverse landraces.
Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

This research focused on evaluating and comparing the perceptions, water-use behaviour, water conservation awareness and overall water stewardship of participants residing in Hammanskraal and Atteridgeville who have experienced intermittent water supply in their domestic households – due to either water contamination incidents caused by dilapidated infrastructure or water restrictions implemented by the City of Tshwane Metropolitan Municipality during the 2016–2017 drought in the Gauteng Province. The research concluded that the municipality needs to implement proactive water conservation awareness initiatives on an ongoing basis to reduce high water demands and to create a culture of water stewardship, especially in Atteridgeville. Transparent communication is also required from the municipality to instil the necessary trust among the public. It is recommended that the municipality attends to water leaks and ongoing complaints from the public timeously to reduce the current apathy from the public against reporting water-related issues and to ultimately ensure compliance to water restrictions.
Geography
M.Sc. (Geography)

South Africa’s growing elephant populations are concentrated in relatively small enclosed protected areas resulting in the over utilisation of the available food sources. Elephants and other herbivores as well as other natural disturbances such as fires and droughts play an important role in maintaining savannah environments. When these disturbances become too concentrated in a particular area the vegetation composition may be negatively affected. Excessive damage to the vegetation would result from exceeding the capacity of a protected area to provide food resources. The effect of the 120 elephants on the vegetation of Welgevonden Private Game Reserve, is not known. The rugged terrain of this reserve makes it a difficult, time consuming and labour intensive exercise to conduct ground studies. Satellite images can be used as a monitoring tool for vegetation change and improve the quantity and quality of environmental data to be collected significantly, allowing more informed management decision-making. This study evaluated the use of satellite imagery for monitoring elephant induced vegetation change on Welgevonden Private Game Reserve. The LANDSAT Thematic Mapper multispectral images, acquired at two yearly intervals from 1993 until 2007 were used. However, no suitable images were available for the years 1997, 2001 and 2003. A series of vegetation change maps was produced and the distribution of water sources and fire occurrences mapped. The areas of change were then correlated with the spatial distribution of water points and fire occurances, with uncorrelated areas of change. This was analysed using large animal population trends, weather data and management practices. On the visual comparison of the vegetation maps, it was seen that over this time period there was some decrease and thinning of woodland, but the most notable change was the increase of open woodland and decrease in grasslands. Using only the digital change detection for the period 1993 to 2007, a general increase in vegetation cover is seen. But this generalisation is misleading, since comparing the digital change detection to the vegetation maps indicates that while vegetation cover may have increased, significant changes occurred in the vegetation types. Most of the areas of significant change that were identified showed a strong positive correlation with burnt areas. The distribution of the water sources could not be directly linked to the vegetation change although rainfall fluctuations seemed to have accelerated vegetation changes. Years with high game counts, such as 1999, also coincide with very low rainfall making it difficult to differentiate between the effects of heavy utilisation of vegetation and low rainfall. Furthermore, many of the initial vegetation changes could be the result of land use changes due to the introduction of browsers, selective grazers and elephants that allow for more natural utilisation of the vegetation. Remote sensing makes it possible to successfully track changes in vegetation and identify areas of potential elephant induced vegetation change. Vegetation changes caused by disturbances, such as fire and anthropogenic activities, can be accounted for but it is not possible to conclude with a high level of certainty that the further changes seen are solely a result of elephant damage. Further work is required to reliably isolate elephant induced vegetation changes, as well as to establish the effects these changes have on the ecosystem as a whole.
Environmental Sciences
(M. Sc. (Environmetal Sciences))