The aim of this research is to examine the contextual environment in which farmers operate so as to improve our understanding of the factors shaping vulnerability to climate risk. A key focus is on the livelihoods of sugarcane farmers, using a case study of small-, medium-scale (emerging) and large-scale sugarcane farmers in the KwaZulu-Natal Midlands area of Eston and its surrounds. A social vulnerability assessment was undertaken under the Sustainable Livelihoods Framework (SLF) to test the hypothesis that climate risk is considered a major contributing factor to the vulnerability of commercial farmers in KwaZulu-Natal and needs to be effectively managed. This involved an investigation into the multiple stresses (both external and internal, on-farm and off-farm, climatic and non climatic) acting on the system. It is clear that climate change risk and variability is a major, but not the sole contributing factor to the vulnerability of commercial farmers in this part of KwaZulu-Natal. Climate change does need to be effectively managed but it will be best done in conjunction with the management of the other multiple and interacting threats and stresses identified in this study. Climate change and vulnerability, as well as the other multiple stresses, are acting on an already vulnerable system, exacerbating and compounding present risks. This research also explored a number of coping and response strategies that commercial farmers have adopted in response to the threats and stresses and investigated particularly, what elements enhance or restrict these strategies (both on-farm and off-farm). These strategies posses potential as possible future adaptation options. It was found that the issues of access to livelihood assets (social, financial, natural/environmental, physical, human, knowledge assets and capital under the SLF) are key to the adaptive capacity and the adaptation strategies that farmers employ. Institutions (both formal and informal) play a pivotal role in this access to livelihood assets both enabling and restricting access. In conclusion, this work determined that a focus on only one element, such as climate change, will not significantly reduce the vulnerability of commercial farmers. There is an interactive, dynamic and multifaceted network present with a number of factors acting within and from outside the system. Political, biophysical, social and economic factors interact and combine to compound vulnerability, requiring more integrative and multiple response strategies.

This study investigates the process of index construction as a means of measuring a hypothetical construct that can typically not be measured by a single question or item in a survey study and applying it as a method of market segmentation. The availability of incidental secondary data that were gathered during 2009 provides a relevant quantitative basis to illustrate this process by constructing a commercial farming sophistication index for South Africa. A multi-step approach was followed for the construction of the commercial farming sophistication index, namely: (1) Selection of items and definition of variables that are most likely to be indicators of commercial farming sophistication; (2) combining of variables into an index; and (3) segmentation and index validation. Following the investigation and illustration of the process of index construction as a method of market segmentation, it was evident that this approach offers an appropriate and useful means of segmenting a market. Several factors contribute to the appeal of this approach. Amongst other, it contributes towards addressing important priorities in the area of future segmentation research, namely that of investigating the application of new base variables into segmentation models, as well as investigating new segmentation strategies. The approach also applies a creative process of combining several base variables into a single measure, namely that of an index variable. By offering classification rules based on characteristics that can easily be observed or elicited by asking a few key questions, new or potential buyers can be grouped by buying behaviour segment. Furthermore, the multi-step process that was employed has pragmatic appeal for researcher, and provides a systematic and structured multivariate approach to segmentation. It also facilitates replication of the process when conducting future studies. By using an index, it takes advantage of any intensity structure that may exist among attributes. This has the advantage that it places members of the market on a continuum that can lead to tracking members’ development paths as they progress towards higher levels on the index. Furthermore, illustration of the process has significant application value in other business-to-business markets, locally and internationally, where index variables can be constructed from both primary and secondary sources and used as a method of segmentation following a similar multi-step approach proposed in this study. Lastly, the outcome of this type of segmentation method offers researchers and marketing practitioners a procedure, in the form of an equation, to calculate index scores and provide rules to segment the market based on predefined intervals. Hence, the challenge to replicate segment formation across independent future studies is addressed. This process is considered an advantage over employing a technique such as cluster analysis, where the use of new data or changes to the clustering algorithm often leads to different segment solutions. / Thesis (PhD)--University of Pretoria, 2012. / Marketing Management / PhD / Unrestricted

Commercial farming of mud crab Scylla serrata is a significant industry throughout South East Asia. The limited scientific knowledge of mud crab nutritional requirements and digestive processes, however, is recognised as a major constraint to the future growth of this industry. To better understand the mechanisms of digestion in the mud crab we have analysed the diversity of digestive enzymes from the hepatopancreas. Significant protease, amylase,cellulase and xylanase activities were detected in soluble extracts from this organ. Temperature profiles for all enzymes were basically similar with optimal activities observed at 500C. Examination of pH tolerance revealed optimal activities for protease and amylase at pH 7.0 while optimal activities for cellulase and xylanase were observed at pH 5.5. Under optimum conditions,protease and amylase activities were approximately two orders of magnitude greater than those seen for either cellulase or xylanase. Interestingly, hepatopancreatic extracts were able to liberate glucose from either starch or carboxymethyl (CM)-cellulose suggesting that a range of carbohydrates may be utilised as energy sources. The effects of dietary carbohydrates on feed digestibility, digestive enzyme levels and growth were also studied by inclusion of additional starch or CM-cellulose at the expense of casein in formulated diets. It was shown that amylase, cellulase and xylanase activities in extracts from the hepatopancreas were highest in mud crabs fed diets containing 47% carbohydrate. Based on the findings, we suggest that the ability of the mud crab to modulate digestive enzyme activities may represent a mechanism to maximise access to essential nutrients when the dietary profile changes.

Magister Artium - MA / Climate has been changing significantly around the globe; hence climate variability is of great interest to researchers. The changes in climate have caused variances in rainfall and temperature, both elements of paramount importance in farming, whether commercial or communal farming. As these fluctuations in temperature and rainfall occur, they cause direct impacts on different livelihoods, fauna and flora. The aim of this thesis is to investigate the human management responses of farmers in two different contexts of communal farming (Makolokwe) and commercial farming (Touws River valley), with a focus investigation on the adaptation and coping strategies of the farmers, as well as spatial analysis of the vegetation and rainfall variability. Farmers were asked to discuss climate and adaptation based on the rainfall data available as well as far as they could remember the occurrence of changes. Rainfall data was available between 1988 and 2017 for Touws River, while the data utilised for Makolokwe was available between 1928 and 2016. The link between the local knowledge of the farmers and scientific knowledge is an important aspect of this research. The Normalised Difference Vegetation Index (NDVI) was used to analyse the vegetation changes on a temporal and spatial scale in the context of Makolokwe and Touws River valley respectively. The differing variations in climate variability and change experienced by the two farming communities are placed alongside an exploration of the adaptation and coping measures which are put in place by farmers as a response to the changes evident in climate, as it allows for better and thorough understanding of the occurring changes in the two communities. The study found that perceptions about climate variability vary in the two communities although there are some common factors. Farmers’ perceptions about climate variability are drawn from their own observations at a local level as well as knowledge from the media regarding terms such as El Niño and drought. Farmers in both communities indicated that they experienced insufficient rain in the winter months which had an impact on the grazing areas and the management of the livestock. These months also threatened livelihoods, especially for farmers who depend on their livestock for their livelihood, in particular communal farmers. Perceptions of factors such as decreasing grazing and vegetation in their environments have led to the adoption of adaptation and coping strategies on the part of farmers. Commercial farmers have more choices in this regard than communal farmers, such as converting to game farming. Common coping strategies include: (1) farmers have had to subsidise and use alternative food sources for the livestock, (2) livestock numbers have been reduced in order to adapt to climate variability, with an impact on livelihoods (3) farmers have had to rely on their hope and faith that things will get better. Planning for climate variability is challenging for land managers. Knowledge and access to resources is therefore essential in ensuring that farmers are kept on track with the changing environment.