KovsieScholar Repository
KovsieScholar is a digital service that collects, preserves, and distributes digital material. Repositories are important tools for preserving an organization's legacy; they facilitate digital preservation and scholarly communication.
Communities in DSpace
Select a community to browse its collections.
Recent Submissions
Evaluating the impacts of local dumping site pollution on arthropods and a quest for novel soil fungal species with potential plastic bioremediation capabilities in the Eastern region of Free State, South Africa
(University of the Free State, 2024) Kheswa, Nozipho; Dube, Nontembeko; Gokul, Arun
Most municipal solid waste (MSW) landfills in South Africa fail to meet regulatory standards due to resource constraints in municipalities and the increasing volume of waste generated by households and local industries. Landfills are designed to contain waste and prevent leachate from contaminating the surrounding environment; however, poor management can lead to severe environmental damage and public health risks. Studies in the Free State province indicate
that most landfills are non-compliant with regulations, contributing significantly to environmental pollution. The Maluti-a-Phofung municipality, for example, faces substantial waste management challenges, with only 25% of households receiving regular refuse collection services, leading to illegal dumping and unmanaged waste sites near residential areas, heightening environmental and health risks.
Leachate from landfills contaminates soil and water, adversely affecting ecosystems and human health, and improper compaction and containment of waste is a major operational shortcoming. Ecotoxicologists assess the heavy metal concentrations to evaluate potential ecological risks in terrestrial environments and assess the impact when these concentrations are concerning. Furthermore, plastic waste, which is more resistant to degradation compared to organic matter, poses significant threats to terrestrial and aquatic life. Despite the urgency of these challenges, the environmental and health hazards of poorly managed landfills remain under-researched in South Africa. This study aimed to evaluate the toxicity of landfills by measuring heavy metal concentrations in soil samples from an active landfill site in Harrismith (H-landfill) and a dormant landfill site in Phuthaditjhaba (P-landfill); assess the toxicity impact of landfill soils on ground-dwelling organisms such as earthworms and collembolans through ecotoxicological tests. Both sites are in close proximity to households and are unregulated. This study also examined how these landfills impact arthropod assemblages during wet and dry seasons, as arthropods are vital bioindicators for assessing the effects of anthropogenic activities. Furthermore, the potential for bioremediation using local fungal isolates was explored.
Results showed that heavy metals, including copper (Cu), lead (Pb), cadmium (Cd), manganese (Mn), and chromium (Cr), exceeded permissible limits for soil, irrigation, and agricultural use. The study revealed that lead (Pb), a highly toxic element with no biological function, had concentrations above allowable limits. Ecotoxicological tests revealed that 65% of earthworms exhibited avoidance behaviour at the Harrismith landfill, indicating higher toxicity at this site,
while 80% did not avoid the Phuthaditjhaba landfill, likely due to lower heavy metal concentrations. Collembolan reproductive rates did not show significant differences between landfill and control soils, suggesting low sensitivity to sublethal toxicity. These findings underscore the environmental hazards associated with landfill contamination, particularly the presence of toxic heavy metals above permissible limits and highlight the need for restoration
efforts following landfill closure to prevent ecological and public health risks.
Arthropods were collected using pitfall traps during wet and dry seasons. Eleven arthropod taxa were recorded in landfills compared to nine in control sites, with significant representation from the orders Diptera, Hymenoptera, Coleoptera, and Araneae. A total of 10 547 arthropods was recorded from Harrismith and Phuthaditjhaba landfills. Arthropod abundance and diversity were notably higher in landfill sites, especially during the wet season, with 9354 individuals recorded compared to 3684 in control sites. In contrast, the dry season yielded fewer individuals, with 1193 in landfills versus 788 in control sites. Dipteran families such as Muscidae, Simulidae, and Calliphoridae were more abundant in landfill sites and are known for their medical importance, indicating potential public health risks. These findings demonstrate that landfills attract arthropod families that may affect human health and suggest that waste and
pollution in landfills support diverse arthropod communities, particularly detritivores, which were less common in control sites. This study is the first to report arthropod assemblages in the landfill sites in the country. The high insect populations and the prevalence of dipteran families point to poor waste management practices and indicate the dual impact of these species as potential disease vectors and decomposers.
Eighteen fungal isolates were identified, nine of which demonstrated the ability to degrade polyethylene (PE) plastic, a common environmental pollutant. The most effective strains, viz., 𝘗𝘦𝘯𝘪𝘤𝘪𝘭𝘭𝘪𝘶𝘮 𝘤𝘩𝘳𝘺𝘴𝘰𝘨𝘦𝘯𝘶𝘮 SP17MK, 𝘈𝘴𝘱𝘦𝘳𝘨𝘪𝘭𝘭𝘶𝘴 𝘤𝘳𝘦𝘣𝘦𝘳 SP6MK, and 𝘌𝘯𝘨𝘺𝘥𝘰𝘯𝘵𝘪𝘶𝘮 𝘢𝘭𝘣𝘶𝘮 SP3MK, caused over 20% weight loss in PE plastic. FTIR analysis revealed significant changes in the plastic's chemical structure, with reductions in absorption peaks at 719 and 1472 cm⁻¹, indicating degradation. Additionally, 𝘋𝘪𝘥𝘺𝘮𝘰𝘴𝘱𝘩𝘢𝘦𝘳𝘪𝘢 𝘷𝘢𝘳𝘪𝘢𝘣𝘪𝘭𝘦 SP11INT and 𝘓𝘦𝘤𝘢𝘯𝘪𝘤𝘪𝘭𝘭𝘪𝘶𝘮 𝘤𝘰𝘱𝘳𝘰𝘱𝘩𝘪𝘭𝘶𝘮 SP7MK were discovered for the first time as potential plastic-degrading fungi. These findings suggest that local fungal species can be utilized in waste management strategies to mitigate plastic pollution in landfill sites. Use of fungal isolates for plastic bioremediation now has a record in South Africa. The identification of fungal isolates with plastic-degrading potential offers a promising avenue for bioremediation and highlights the importance of exploring local microorganisms as part of sustainable solutions to plastic pollution. Further research is needed to optimise these fungal species for large-scale environmental applications and waste management strategies.
Invasive status of pampas grass in South Africa
(University of the Free State, 2024) Mbele, Thembelihle Joyce; Canavan, K.; Steenhuisen, S.
Two 𝘊𝘰𝘳𝘵𝘢𝘥𝘦𝘳𝘪𝘢 species, 𝘊. 𝘫𝘶𝘣𝘢𝘵𝘢 and 𝘊. 𝘴𝘦𝘭𝘭𝘰𝘢𝘯𝘢 have become invasive outside their native range, including in South Africa. They were introduced to South Africa for ornamental use, erosion control and stabilising mine-dumps. They have long escaped containment and spread throughout the country, invading grasslands, roadsides, wastelands, rivers and seasonally wet habitats. Little is known regarding their distribution, seed viability and whether accurate identifications have been made of the 𝘊𝘰𝘳𝘵𝘢𝘥𝘦𝘳𝘪𝘢 species in South Africa, which may hinder effective management. Although the national regulations forbid the trade of pampas grass, the continuing popularity of their inflorescences for home décor and special events is of concern. While nurseries have stopped the sale of the plants, inflorescences are still being sold through retail and informal trade. This study aimed to assess the invasion risk posed by pampas grass in South Africa and distinguish between the different species across their invaded range using molecular techniques. Leaf and seed samples were collected from 79 populations across South Africa.
Eight microsatellite primers were used to assess the genetic variation across 𝘊𝘰𝘳𝘵𝘢𝘥𝘦𝘳𝘪𝘢a populations. Seed viability and germination success were assessed for seeds from 28 naturalised and 13 traded inflorescences using a triphenyl tetrazolium stain, and germination trials in a growth chamber and greenhouse. Impacts and risks of 𝘊. 𝘫𝘶𝘣𝘢𝘵𝘢 and 𝘊. 𝘴𝘦𝘭𝘭𝘰𝘢𝘯𝘢 in South Africa were assessed using version 1.2 Risk Analysis for Alien Taxa (RAAT) framework. Microsatellite confirmed the presence of 𝘊. 𝘫𝘶𝘣𝘢𝘵𝘢 and 𝘊. 𝘴𝘦𝘭𝘭𝘰𝘢𝘯𝘢 in South Africa and that 𝘊. 𝘴𝘦𝘭𝘭𝘰𝘢𝘯𝘢 populations have higher genetic diversity compared to 𝘊𝘰𝘳𝘵𝘢𝘥𝘦𝘳𝘪𝘢 from other invaded regions. Tetrazolium tests found that 𝘊. 𝘴𝘦𝘭𝘭𝘰𝘢𝘯𝘢 (71.66 %) had higher seed viability than 𝘊. 𝘫𝘶𝘣𝘢𝘵𝘢 (54.28 %). Assessments of germination trials in a growth chamber revealed that 𝘊. 𝘫𝘶𝘣𝘢𝘵𝘢 (68.89%) had a higher proportion of seeds germinate compared to 𝘊. 𝘫𝘶𝘣𝘢𝘵𝘢 (52.62 %) but this difference was not statistically significant. Seed germination under greenhouse experiments also found 𝘊. 𝘴𝘦𝘭𝘭𝘰𝘢𝘯𝘢 (79.15 %) to have higher germination success compared to 𝘊. 𝘫𝘶𝘣𝘢𝘵𝘢 (62.54 %). Seed viability of cultivated and naturalised 𝘊𝘰𝘳𝘵𝘢𝘥𝘦𝘳𝘪𝘢 inflorescences differed significantly to formally traded inflorescences but not significant to informally traded inflorescences. Seeds from naturalised populations of both 𝘊𝘰𝘳𝘵𝘢𝘥𝘦𝘳𝘪𝘢 species had significantly higher germination success (65.69 %, 74.35 %) than the formally (25.00 %, 5.33 %) and informally traded populations (28.75 %, 35.56 %) under growth chamber and greenhouse experiments, respectively. Viability and germination success of seeds from cultivated 𝘊𝘰𝘳𝘵𝘢𝘥𝘦𝘳𝘪𝘢 inflorescences were statistically similar to naturalised inflorescences while those from formally traded inflorescences performed statistically similar to seeds from informally traded inflorescences across triphenyl tetrazolium stain, growth chamber and greenhouse experiments.
The risk analysis assessments determined that both 𝘊. 𝘫𝘶𝘣𝘢𝘵𝘢 and 𝘊. 𝘴𝘦𝘭𝘭𝘰𝘢𝘯𝘢 have major impacts and a high risk of invasion in South Africa with medium ease of management. Determining the invasion risk posed by pampas grass in South Africa has provided important information on managing these species. Biological control is species-specific; therefore, this study has provided information that will guide the biological control programme of pampas grass in South Africa and future research can focus on finding potential biocontrol agents. Seed viability and germination experiments established that when seeds are present on flowers, most of them are viable and that traded inflorescences’ seeds are not sterile and can thus be promoting invasion and further spread of 𝘊𝘰𝘳𝘵𝘢𝘥𝘦𝘳𝘪𝘢 species. Effective management of 𝘊𝘰𝘳𝘵𝘢𝘥𝘦𝘳𝘪𝘢 species must focus on enforcing legislation to stop this pathway of spread.
Demographics of alien willows in the Grassland Biome of South Africa
(University of the Free State, 2024) Mashamba, Tapiwanashe; Steenhuisen, Sandy-Lynn; Martin, Grant; Payne, Stephanie
Invasive alien species present a critical threat to biodiversity, ecosystem services, and agricultural productivity worldwide. This study examines the distribution, demographic dynamics, and ecological impacts of 𝘚𝘢𝘭𝘪𝘹 𝘣𝘢𝘣𝘺𝘭𝘰𝘯𝘪𝘤𝘢 L. (weeping willow) and 𝘚𝘢𝘭𝘪𝘹 𝘧𝘳𝘢𝘨𝘪𝘭𝘪𝘴 L. (crack willow) within the Grassland biome of the Eastern Free State, South Africa. These invasive species, introduced for ornamental and functional purposes, have shown extensive colonization, particularly in riparian zones, where they outcompete native vegetation and alter hydrological processes.
The research combines historical and contemporary data sources to evaluate changes in the population structure and spatial distribution of these species over time. Using aerial photographs from 1984 and 2023, supplemented with roadside surveys and Google Street View (GSV) analysis, the study provides an assessment of the species’ demographics. Additionally, field-based verification of GSV-derived data validates its utility as a cost-effective tool for mapping and monitoring invasive alien plants.
The study confirms that 𝘚. 𝘣𝘢𝘣𝘺𝘭𝘰𝘯𝘪𝘤𝘢 and 𝘚. 𝘧𝘳𝘢𝘨𝘪𝘭𝘪𝘴 remain prevalent along watercourses, roadsides, and disturbed areas, with 𝘚. 𝘣𝘢𝘣𝘺𝘭𝘰𝘯𝘪𝘤𝘢 exhibiting a broader distribution along roadsides with approximately 50% of the sites having a population size of 1-5 trees. Although 𝘚. 𝘧𝘳𝘢𝘨𝘪𝘭𝘪𝘴 is not as widely distributed as 𝘚. 𝘣𝘢𝘣𝘺𝘭𝘰𝘯𝘪𝘤𝘢 it dominates the areas in which it is found, forming pure stands; 56% of the sites surveyed consisted of 6 or more trees. Gender analyses of 𝘚. 𝘣𝘢𝘣𝘺𝘭𝘰𝘯𝘪𝘤𝘢 populations reveal a predominance of female trees which suggests that its propagation is mainly asexual.
The demographic study done through road surveys and GSV reveals limited recruitment of 𝘚. 𝘣𝘢𝘣𝘺𝘭𝘰𝘯𝘪𝘤𝘢 in recent decades, suggesting a potential decline in its invasive potential with almost 80% of the population consisting of adult or dying trees. In contrast, 𝘚. 𝘧𝘳𝘢𝘨𝘪𝘭𝘪𝘴 populations display a continuous expansion with healthy recruitment, with 44% of the trees recorded as seedlings, young trees, or mature trees. This expansion indicates that 𝘚. 𝘧𝘳𝘢𝘨𝘪𝘭𝘪𝘴 is now more invasive than 𝘚. 𝘣𝘢𝘣𝘺𝘭𝘰𝘯𝘪𝘤𝘢, which increases the need for a tailored management strategy to address this invasive species.
The research also investigates interactions between invasive willows and invertebrate communities. Surveys at selected sites document the presence of 348 individual insects and one arachnid, representing 21 families, with 14 species associated with both willow species. Another finding was the presence of crown galls on 27.5% on the 𝘚. 𝘣𝘢𝘣𝘺𝘭𝘰𝘯𝘪𝘤𝘢 population surveyed. Invasive willows provide habitat and resources for certain insect populations. Some of these insects, specifically 𝘗𝘭𝘢𝘨𝘪𝘰𝘴𝘵𝘦𝘳𝘯𝘢 𝘥𝘪𝘴𝘤𝘰𝘭𝘰𝘳, 𝘛𝘶𝘣𝘦𝘳𝘰𝘭𝘢𝘤𝘩𝘯𝘶𝘴 𝘴𝘢𝘭𝘪𝘨𝘯𝘶𝘴 𝘢𝘯𝘥 𝘏𝘦𝘭𝘪𝘰𝘯𝘪𝘥𝘪𝘢 𝘲𝘶𝘢𝘥𝘳𝘪𝘮𝘢𝘤𝘶𝘭𝘢𝘵𝘢, along with gall-inducing bacteria (potentially 𝘈𝘨𝘳𝘰𝘣𝘢𝘤𝘵𝘦𝘳𝘪𝘶𝘮 𝘵𝘶𝘮𝘦𝘧𝘢𝘤𝘪𝘦𝘯𝘴), recorded within the 𝘚. 𝘣𝘢𝘣𝘺𝘭𝘰𝘯𝘪𝘤𝘢 populations could be resulting in the decline of this invasive species.
This study explored the use of ArcGIS and GSV, to assess invasive tree distributions and potential of these tools to monitor the spread of invasive trees over time. The comparison of historical and current data reveals significant efficiency of GSV as a monitoring tool, offering a cheap and quick approach to invasive species management in resource-limited settings.
Policy implications of the findings are discussed with reference to South African legislation, including the Conservation of Agricultural Resources Act (CARA) of 1983 and the National Environmental Management: Biodiversity Act (NEMBA). 𝘚𝘢𝘭𝘪𝘹 𝘣𝘢𝘣𝘺𝘭𝘰𝘯𝘪𝘤𝘢 and 𝘚. 𝘧𝘳𝘢𝘨𝘪𝘭𝘪𝘴 have been classified as Category 2 invaders under CARA but are not found under the NEMBA Act. This may result in challenges in effectively controlling 𝘚. 𝘣𝘢𝘣𝘺𝘭𝘰𝘯𝘪𝘤𝘢 and 𝘚. 𝘧𝘳𝘢𝘨𝘪𝘭𝘪𝘴.
This dissertation contributes to the field of biological invasions by providing an updated assessment of invasive willows in the Grassland biome, thereby offering insights for land managers, conservationists, and policymakers. The study concludes by emphasizing the importance of integrating historical data and modern geospatial tools, as an informative approach to develop effective management solutions for invasive alien plants. The methodological framework and findings presented herein offer valuable lessons for addressing invasive species challenges in similar ecological contexts globally.
The effect of milk replacers containing fermented plant protein and a higher carbohydrate content on the growth performance and profitability of Holstein bull calves
(University of the Free State, 2025) Kriel, Elsa Ena; Einkamerer, Ockert Bernard; van Zyl, Johannes Hendrik Combrink
𝑬𝒏𝒈𝒍𝒊𝒔𝒉
The objective of this study was to evaluate the biological and economic viability of alternative milk replacers for Holstein bull calves, focusing on high-carbohydrate and fermented plant protein-based formulations. The primary goals were to assess the impact of these alternatives on calf growth, health, and profitability by identify the most cost-effective options for farmers.
𝗖𝗵𝗮𝗽𝘁𝗲𝗿 𝟯 investigate the effects of fermented plant protein (FP) and increased carbohydrate (HC) levels in milk replacers on calf growth performance. Four different milk replacers were formulated: a
conventional replacer (A), one with 20% fermented plant protein (B), a high-carbohydrate replacer (C), and a high-carbohydrate replacer with 20% fermented protein (D). These milk replacers were tested in a 77-day trial (TP, total phase) involving 32 Holstein bull calves, which were randomly assigned to four treatments (n = 8). The trial was divided into two phases: Phase 1 (P1, days 0–63), where milk replacers were fed, and Phase 2 (P2, a two-week post-weaning period), designed to evaluate weaning shock. Milk replacer intake was controlled, while starter meal intake was offered 𝘢𝘥 𝘭𝘪𝘣𝘪𝘵𝘶𝘮. Growth performance metrics such as weight gain, dry matter intake (DMI), average daily gain (ADG), DMI as a percentage of body weight (DMI/BW%), and feed conversion ratio (FCR) were analysed using a factorial ANOVA. An interaction was observed for TP FCR (P = 0.036). Except for controlled milk replacer intake and P2 DMI/BW% and P2 FCR, milk replacers containing FP generally resulted in poorer performance (P < 0.05) compared to milk replacers containing standard protein (SP). The lower performance was attributed to the higher levels of trypsin inhibitors present in the FP, which negatively impacted calf growth. High-carbohydrate milk replacers promoted greater starter meal intake during all phases (P < 0.05) and is recommended. Fermented protein should only be considered when the fermentation process is improved to reduce trypsin inhibitor levels to below 4 mg/g of protein.
𝗖𝗵𝗮𝗽𝘁𝗲𝗿 𝟰 shifts focus to the financial analysis, comparing the cost-effectiveness of the different milk replacers (A, B, C and D). Financial parameters such as total cost, average daily cost (ADC), cost per weight gain (Cost/WD), and income from the sale of calves were assessed. In terms of overall cost and ADC, treatment D was the most economical, with a total feeding cost of R2739.40 per calf for TP. However, when factoring in feed conversion ratio (FCR), treatment C was the most costeffective, with the highest income and lowest cost per unit weight gain (R58.83), although not significantly different when compared to Treatments A and D.
𝗖𝗵𝗮𝗽𝘁𝗲𝗿 𝟱 extends the financial analysis by exploring the use of girth circumference weight estimation tapes as an alternative to expensive electronic scales. This method is valuable for calf
management, as weight is crucial for feed management and medication protocols. The study found that while the specific tape used in the trial overestimated calf weights, it holds potential as a lowcost alternative, with further refinement needed. The data collected can contribute to the development of a larger database to improve future weight prediction tools.
𝗜𝗻 𝗰𝗼𝗻𝗰𝗹𝘂𝘀𝗶𝗼𝗻, this study demonstrates that high-carbohydrate milk replacers are a viable and costeffective alternative to conventional formulations, offering potential cost savings without sacrificing calf growth performance. While fermented plant protein showed promise as a cost-effective protein source, its effectiveness in this trial was reduced by the presence of trypsin inhibitors, which could be addressed through improved processing methods. Additionally, Chapter 5's exploration of girth circumference measurement as a cost-effective weight estimation tool further supports the economic viability of alternative approaches to calf rearing. The findings highlight the need for ongoing research to optimize these alternatives and improve profitability in the dairy industry.
___________________________________________________________________
Pilot-scale wastewater surveillance for pathogenic yeasts in Mangaung, South Africa
(University of the Free State, 2025) Baker, Tyla; Pohl-Albertyn, C. H.; Albertyn, J.; Musoke, J.
Considering the emerging concern posed by invasive fungal infections, it is important to study the dissemination and proliferation of pathogenic fungal species in the environment. It is crucial to identify major vectors that aid in the spread or act as a hub for pathogenic yeasts in order to prevent infections in susceptible individuals, which mainly include individuals who are immunocompromised or immunosuppressed. 𝘊𝘢𝘯𝘥𝘪𝘥𝘢, 𝘊𝘳𝘺𝘱𝘵𝘰𝘤𝘰𝘤𝘤𝘶𝘴 𝘢𝘯𝘥 𝘙𝘩𝘰𝘥𝘰𝘵𝘰𝘳𝘶𝘭𝘢 species are commonly found in a variety of water sources with which humans are in frequent contact through daily activities like bathing, washing clothes and cooking. The World Health Organisation has recently published a list of priority pathogens in which fungi are classified into critical, high and medium-priority groups. 𝘊𝘢𝘯𝘥𝘪𝘥𝘢 species are found in all three levels and 𝘊𝘳𝘺𝘱𝘵𝘰𝘤𝘰𝘤𝘤𝘶𝘴 species are in critical and medium groups. This further warrants the investigation into the possibility that infections may occur through contact with yeastcontaminated water. In addition, the close association between antifungal pollutants and yeast in water may induce antifungal resistance development, further complicating the effective treatment of these infections. Thus, it is important to investigate the presence and antifungal susceptibility of yeast found in water as well as to identify ways to monitor potential fungal outbreaks, including through wastewater surveillance. This review deals with the occurrence and infection risks posed by pathogenic yeasts in water as well as the possibility of these yeasts acquiring antifungal resistance due to the simultaneous presence of antifungal compounds from medical and agricultural runoff.
Survival, behavioural changes and geotaxis response of 𝘊𝘶𝘭𝘦𝘹 SP. Larvae (CULICIDAE) after exposure to carbaryl and pymetrozine
(University of the Free State, 2024) Radebe, Nonhlahla; Otomo, Patricks Voua; Obame-Nkoghe, Judicaël; Mnkandla, Sanele Michelle
Pesticides play a crucial role in agriculture and are extensively used in developing countries to ensure food security and economic prosperity. However, as the climate is changing (rise in temperature and precipitation), the efficacy of pesticides is reduced leading to more frequent application and extensive use of pesticides causing greater adverse effects on aquatic systems. South Africa is not spared from this pesticide pollution. To mitigate the environmental effects of pesticides in South Africa, (particularly QwaQwa where many farms are situated), the least toxic pesticides such as pymetrozine (a selective “Environmental Protection Agency Reduced Risk pesticide”) should be preferably used and recommended for Integrated Pesticides Management (IPM) whereas highly toxic ones such as carbaryl should be phased out to reduce pesticide pollution and unintended death of non-target aquatic organisms. The present comparative study aimed to evaluate the effects of carbaryl and pymetrozine on the behaviour of mosquito larvae (𝘊𝘶𝘭𝘦𝘹 sp.). Mortality experiments showed that carbaryl (0, 12.50, 25, 50 and 100 µg/L) caused more mortality than pymetrozine (0, 6.25, 12. 50, 25 and 50 mg/L), and exposure to both insecticides altered the breathing, swimming and resting behaviours of the mosquito larvae. There was mortality in all tested concentrations, except for distilled water (control). The highest mortality was recorded in 100 µg/L of carbaryl. Carbaryl had an LC₅₀ of 0.028 mg/L, whereas pymetrozine generated a lethal concentration 50 (LC₅₀ of 181.950 mg/L, this proves the high toxicity of carbaryl as the LC₅₀ of carbaryl is more than 100 times smaller than that of pymetrozine. The larvae spent more time breathing in the absence of these insecticides, more time swimming in the presence of carbaryl and more time resting in the presence of pymetrozine. Moreover, these toxicants altered the geotaxis of these organisms thus compromising their fitness. The larvae predominantly displayed negative geotaxis (spent more time breathing) when exposed to both these insecticides. From these findings, it can be noted that pymetrozine was the least toxic of the two pesticides. Hence, pymetrozine can be recommended for IPM. This was supported by a systematic review of 24 years of carbaryl effects on insect behaviour. The overall results revealed that carbaryl should be phased out in favour of less toxic yet effective insecticides like pymetrozine.
Genomic evaluation in different environments in the South African holstein breed
(University of the Free State, 2024) van Niekerk, Michiel; Neser, F. W. C.; Ducrocq, V.
Fixed regression model (FRM) analyses that consider only fixed, non-genetic effects to vary over the lactation are currently used for genetic evaluation of production traits in South African Holstein. With random regression models (RRM), the random animal and permanent environmental effects are allowed to also vary over the lactation. Hence, RRM can account for an individual component representing changes during the lactation i.e., its persistency (PERS), enabling selection for more persistent cows. Also, test-day (TD) records used for genetic evaluations come from cows in contrasted production systems. The main ones rely on full pasture (PAST) or a total mixed ration (TMR), a choice often depending on local average rainfall where herds are situated. TD records from herds were divided into two datasets based on the production system (PAST or TMR). REML was used to analyse production for each of the first three lactations under different multiple-lactation models for milk, fat and protein production, as well as fat and protein percentage. Various FRM were compared to the current FRM officially used for genetic evaluation in South Africa (saFRM).
A FRM that cumulates different curves over the lactation for different fixed effects was retained based on results in the PAST dataset and was also applied to the TMR dataset. This model was then broadened to an alternative RRM (aRRM) combining for each lactation an average production and a PERS effect, after which it was compared to the current saFRM under both production systems. The aRRM for both PAST and TMR had a better goodness of fit than the current saFRM for all traits except protein percentage. The mean squared error of aRRM was lower for all traits. Generally, aRRM heritability estimates were higher than with the saFRM at the beginning and end of lactation for most traits in PAST while being mostly higher during late lactation in TMR. Overall, the h² in PAST were mostly higher than in TMR for all traits. Estimates of between-lactations genetic correlations for average production from the aRRM were generally higher. Within-lactations genetic correlations between average production and PERS for TMR from the aRRM were negative and stronger than for PAST. The extra source of information from the aRRM enables a genetic prediction of PERS and is expected to increase accuracy of genetic predictions. Different genetic parameters between the two production systems may denote a genotype x environment interaction.
Dairy cattle in South Africa (SA) must produce in varying environments which can roughly be separated as total mixed ration (TMR) and pasture (PAST) production systems according to the level of rainfall in the herd area. Previous studies aimed to determine a possible genotype x environment interaction (GxE) using 305-day lactation records, finding no interaction, but different heritabilities. An alternative random regression model (aRRM) was developed using SA Holstein test-day records of herds with known production system used (TMR or PAST, analysed independently). The aRRM separates the animal genetic (additive) effect into an average-production (level) and -persistency (slope) effect and shows clear differences in the genetic variances and heritability estimates over the lactation between TMR and PAST. The aim of this study was to further investigate the existence of a possible GxE interaction, using the same dataset, methods and aRRM to differentiate each trait (milk, fat and protein production for the first three3 lactations) separately for the two production systems (TMR or PAST). The possible reranking of sires on resulting estimated breeding values from the analysis between TMR and PAST were also investigated. Genetic correlations (0.81 to 0.94) of the genetic-average-production effect between TMR and PAST were strong, while corresponding correlations of the genetic-average-persistency effect were weak (Lactation 1, 0.22 to 0.27) to moderate (Lactations 2 and 3, 0.55 to 0.68) for all traits. Minor reranking of sires between TMR and PAST are predicted for genetic-average-production, but with moderate to major reranking for genetic-average-persistency. Analyzing TMR and PAST separately using a reduced rank model fits the data significantly better, adds additional information and allows for more accurate predictions to improve genetic persistency, more so than using within-PAST estimates. The recording of TD records as TMR or PAST should be seriously contemplated as the genetic component of persistency has a significant impact on total production.
Genetic improvement for persistency of milk production in South African Holstein cattle in a total mixed ration or pasture production system will be impeded because of the existence of genotype by environment interaction between the production systems. Previous studies where herds’ production system was known (unlike reality) showed that rainfall level indicates the production system preferred by producers. The study aimed to determine the effect of including average rainfall in a random regression model as a possible proxy for production system used. The animal-additive-genetic effect due to annual rainfall (class) was added to the existing additive-genetic-average-production and -persistency effect. Heritability estimates of rainfall class 1 (‘low’ rainfall) coincided with total mixed ration estimates while rainfall class 5 (‘high’ rainfall) coincided with pasture estimates in later lactations. Results suggest that genetic background responsible for average production level and persistency over the lactations are not consistent over different rainfall areas.
Genomic evaluations for dairy cattle have become standard practice in 23 developed countries according to Interbull at the end of 2024. The development and use of many (tens to hundreds of thousands) single nucleotide markers (SNPs) spread over the whole genome opened new doors for improved genetic predictions. Together with the relatively newly developed single-step (ss) method that blends phenotypic, pedigree and genotypes (indicated by the SNPs of key animals) a new evaluation encompassing all this information in a single genetic analysis. Such a ss, genomic evaluation has been shown to enhance accuracy of prediction for various traits. SA Holsteins do not employ such genomic evaluations due to the relatively high cost of genotyping animals playing a significant role. Some 1221 SA Holstein animals (1143 cows) were, however, genotyped. The production system under which 535 of these cows were recorded for milk production was known. Because of the significant genotype x environment interaction between the two production systems, cumulative 295-days milk production for lactation 1 and 2 in TMR and PAST were analysed as different traits (i.e., four-trait analyses). Two-trait analyses (lactation 1 and 2, irrespective of production system used) were also carried out. Using REML, two multi-trait (MT) i.e., four-trait analyses (MT4) were done. In the first analysis (MT4) genomic information was not implemented and yielded estimated breeding values (EBVs) and their accuracies (ACC). The second analysis was the same as the first (MT4) one, except that the single-step method (ssMT4) was used, which incorporated the genomic information and yielded genomically enhanced EBVs (ssGEBVs) and their ACCs. The two-trait analyses were carried out in the same way; a MT2 and ssMT2 analysis. Heritabilities between the ssMT4 vs the MT4 analyses were similar (TMR lactation 1 estimates of 0.23 vs 0.24, respectively; TMR lactation 2 estimates of 0.16, respectively; PAST lactation 1 estimates of 0.31, respectively; PAST lactation 2 estimates of 0.27, respectively).
Heritabilities for the ssMT2 vs the MT2 analyses were also similar (0.25, respectively for lactation 1, and 0.17 vs 0.18, respectively for lactation 2). Genetic correlations from the ssMT4 between TMR and PAST for lactation 1 and 2 were 0.81 and 0.70, respectively. Hence, minor to moderate reranking of animals on ssGEBVs between the two production systems might take place for lactation 1 and 2, respectively. On average, the largest and significant increase in ssGEBV vs EBV ACCs were for cows with records (0.17; no progeny in the pedigree) and especially for the corresponding cows with the lowest EBV ACCs (increases of ~0.11 to ~0.40). Dams with records (and progeny in the pedigree) had on average the second largest increase in ssGEBVs (0.06), also with the largest increases in dams with the lowest EBV ACCs (increases of ~0.12 to ~0.33). Results for dams without records followed the same tendency. In this regard, results of the ssGEBV vs EBV ACCs for the ss- and MT2 analyses followed a similar trend. These preliminary results are promising for increasing ACC of genetic prediction using ss genomic evaluations. However, more animals need to be genotyped, especially highly influential sires with genetic merits that represent the whole population. Validation of genomic predictions need to be part of future research in the SA Holstein population.
Heritability and expression of grain yield and nutritional characteristics of cowpea
(University of the Free State, 2024) Masemola, Bogaleng Milcah; Mbuma, N. W.; Labuschagne, M. T.; Gerrano, A. S.; Minnaar-Ontong, A.
Cowpea (𝘝𝘪𝘨𝘯𝘢 𝘶𝘯𝘨𝘶𝘪𝘤𝘶𝘭𝘢𝘵𝘢 L. Walp) is an autogamous diploid legume crop. It is highly self-pollinating, yielding high levels of homozygosity and contributing to a narrow genetic base. Improving cowpea depends on identifying and selecting parental genotypes based on commercial characteristics of interest, followed by hybridisation and selection to develop new elite lines that can be evaluated in several environments for performance. A study on the combining ability of selected parental genotypes is expected to provide insight into the selection of potential parental genotypes, gene action and heritability for grain yield and nutritional characteristics. The objective of this study was to determine general combining ability (GCA) and specific combining ability (SCA) effect and heritability of economic traits in selected parental genotypes identify the best parents, and new F1 progenies. A half diallel mating design was used to generate 45 F1 progenies, after which the 55 genotypes (the 45 F1 progenies and 10 parental genotypes) were evaluated for grain yield, yield components and nutritional characteristics at two locations for two seasons using a randomised complete block design with three replications.
The results indicated significant genotype, genotype by environment, GCA by environment and SCA by environment interaction effects for all measured characteristics except for GCA and SCA for iron (Fe) and zinc (Zn) contents. Both additive and non-additive gene effects were important for the expression of the grain yield and nutritional characteristics measured. However, non-additive gene effects were predominant for most of the yield characteristics, implying potential for hybrid breeding. The low to medium narrow-sense heritability observed for all measured characteristics indicated the predominance of non-additive genetic effects, which suggests that selection would be effective for some of the characteristics, but not for those with low heritability. The parental genotypes TVU13953 and IT96D-602 were the best general combiners for grain yield and most yield components. Glenda, IT93K-129-4, TVU7778 and 98K-5301 were the best general combiners for amylose content. Kisumi-mix and 98K-5301 were the best general combiners for protein content, IT845-2246 and TVU-14196 for Fe, and Glenda and ITOOK-1060 for Zn content. Six hybrid progenies (Glenda x TVU13953, 98K-5301 x TVU13953, IT96D-602 x 98K-5301, IT96D-602 x TVU13953, IT96D-602 x Glenda and IT845-2246 x TVU13953) had superior performance for grain yield. TVU7778 x Kisumi-mix, IT845-2246 x 98K-5301, Kisumi-mix x IT93K-129-4, and Kisumi-mix x ITOOK-1060 had the highest SCA (≥ 2.80) effects for protein content.
TVU-14196 x TVU13953 and TVU-14196 x IT845-2246 exhibited noteworthy positive SCA effects for Fe content. Significantly positive SCA effects were observed for Zn in four hybrids: ITOOK-1060 x Glenda, Kisumi-mix x ITOOK-1060, IT96D-602 x ITOOK-1060, and IT96D-602 x IT93K-129-4. The crosses had increased genetic variability, indicating that hybridisation and selection can be used to improve grain yield, yield components, and nutritional characteristics in cowpea. The F1 progenies expressed heterosis, indicating the possibility of hybrid breeding in cowpea. The best general combiners could be used as parental genotypes for future cowpea breeding programmes.
Entrepreneurship resilience and vulnerability reduction in the Afromontane region: analysing the livelihood strategies of female entrepreneurs in Qwaqwa
(University of the Free State, 2024) Dube, Jerit; Magaiza, Grey
Resilience in female entrepreneurship appears as a significant component that critically influences the achievement and capacity to overcome vulnerabilities inherent in the development and management of businesses. Up to now, various scholars in the field of entrepreneurship have understood resilience as a response to adversity extreme events, or disasters. However, this study understands resilience as the ability to bounce back after exposure to vulnerabilities. Concerning female entrepreneurship, this study understands entrepreneurship resilience as the ability of female entrepreneurs to bounce back and reduce their vulnerabilities. To understand entrepreneurship resilience and vulnerability reduction of female entrepreneurs, this study conducted a systematic literature review which indicated that there is an existing gap in the literature on entrepreneurship resilience and vulnerability reduction of female entrepreneurs in marginalised regions like the Afromontane. Thus, due to this existing literature gap, less is known about the vulnerabilities encountered by female entrepreneurs in the Afromontane regions. In the Afromontane regions like QwaQwa for instance, female entrepreneurs are exposed to multidimensional vulnerabilities due to weak resilience capacity. Furthermore, due to a lack of empirical research and a gap in the literature on entrepreneurship resilience and vulnerability reduction, there is less knowledge on the resilience-building strategies that female entrepreneurs in this region can use to reduce their vulnerability exposure. To address the issue of vulnerability and resilience of female entrepreneurs and close this existing gap in literature and knowledge, this study explored entrepreneurship resilience and vulnerability reduction of female entrepreneurs in the Afromontane. It particularly analysed the livelihood strategies of female entrepreneurs in QwaQwa to understand the vulnerabilities they are exposed to, their vulnerability reduction, and entrepreneurship resilience capacity.
This study followed a multi-theoretical framework to understand the multidimensional vulnerabilities encountered by female entrepreneurs in QwaQwa as well as their resilience to these vulnerabilities. In line with the research objectives, a qualitative approach was followed to understand the experiences and perceptions of female entrepreneurs in QwaQwa. Through a participatory approach, a total of 27 female entrepreneurs in QwaQwa were involved in this study. These participants were selected through snowball sampling. Data was collected through in-depth interviews, focus group discussions, life history narratives, transect walks, and entrepreneurship hotspot analysis. Data was thematically analysed using ATLAS ti 22 version. The findings of the study indicate that female entrepreneurs in QwaQwa are exposed to multidimensional vulnerabilities. To reduce their vulnerabilities and strengthen their resilience, the female entrepreneurs in QwaQwa rely on various types of capital. However, though they rely on capital, their vulnerability exposure remains high while their resilience capacity remains low. They have a higher vulnerability exposure and low resilience capacity. The scientific evidence brought by this study indicates that there is a lack of research on female entrepreneurs, resilience, and vulnerability reduction in the QwaQwa region, precisely in QwaQwa. Given this gap in research and literature, female entrepreneurs in this region continue to experience multidimensional vulnerabilities. In an attempt to contribute to the body of knowledge of entrepreneurship resilience and vulnerability reduction, this study developed a vulnerability reduction and entrepreneurship resilience model from the study findings and multi-theoretical framework.
This study hopes that female entrepreneurs in the future will apply the developed model to reduce their vulnerabilities and enhance their entrepreneurship resilience capacity.
Recommendations for policy development and future research emerged and have been provided by this study.
Environmental consciousness among students
(University of the Free State, 2025) Mahlatsi, Bonolo Esther; Pelser, A. J.; Matebesi, S.
Determining individuals’ levels of environmental consciousness is essential in research. Concern about the environment is growing because of the increasing environmental degradation caused by human activities. Environmental consciousness is a term that has become more popular in recent years as environmental problems, largely caused by human activities, have accelerated. Environmental consciousness is a multifaceted concept with four dimensions, including environmental attitude, knowledge, value, and motivation. Environmental consciousness also entails socio-economic and psychological factors relating to an individual’s propensity to engage in pro-environmental behaviour. It focuses on people’s understanding of the environment, its problems, and processes.
The relationship between humans and the environment has been one-sided for centuries, which has resulted in overwhelming and irreparable damage to the environment and ecosystems. This damage is largely due to human consumption causing the vulnerability of social systems. Since environmental problems have escalated to a global agenda, society is starting to question its environmental attitudes and behaviours; there seems to be an attitude-behaviour gap that exists in society. Human consumption and the extinction of species are not considered to be pressing environmental issues, which is problematic. Therefore, engaging people about their environmental behaviour and attitudes towards the environment is essential. Previous studies on environmental consciousness have focused more on consumer behaviour rather than on students’ attitudes and awareness of environmental issues. Therefore, there is a gap in the literature about young people’s attitudes to the environment, their awareness of environmental issues, and their perceptions of environmental sustainability.
This gap in the literature is especially true in the South African context. The scant research is evidence that students’ perceptions of environmental problems are not well-known. Furthermore, how students learn about the environment is not integrated into their primary or secondary schooling or even into higher education curricula. Indeed, understanding the environmental attitudes and behaviour of university students has become a salient topic at South African universities because environmental attitudes and behaviour play a key role in shaping students’ perceptions of the environment at large. Furthermore, many environmental actions taken today are not actually based on protecting the environment from the influence of human activity and consumption. Rather, protecting the environment is a key social and political issue. Therefore, this study aims to explore what South African students’ perceptions of the environment are and what their level of environmental consciousness is. The study also intends to investigate whether students are indifferent or ambivalent towards the environment and environmental issues and, if so, what the reasons behind this attitude are.
The study employed a mixed methods approach embedded in a cross-sectional study. The researcher embedded methodological triangulation to cross-validate the findings of the study to provide a comprehensive analysis. The target population consisted of both undergraduate and postgraduate students. The population also consisted of students from all genders, ages, ethnic groups, and faculties. The random sample size consisted of 380 respondents (at a 95% confidence level and 5% confidence interval). To allow for an estimated sample mortality of 35%, a total sample size of 585 was decided upon. The sampling design was determined with the Simple Random Size calculator.
There were two data collection phases. Phase one (the quantitative component embedded in an exploratory survey design) entailed the dissemination of an online survey. The online survey was administered to a sample of registered students at all three campuses of the University of the Free State (the Bloemfontein, South, and QwaQwa campuses). Phase two (the qualitative component involved inviting the respondents who had completed the online survey to participate in mini groups. A sequential explanatory approach was embedded in the data-gathering processes of both phases. The study adopted a six-step reflexive thematic analysis to examine the participants’ experiences and perceptions of environmental issues.
Factor analysis was conducted to reduce the large dataset into a smaller one made up of fewer factors. Exploratory factor analysis was used in the early stages of the data analysis to explore the interrelationships between the set of variables contained in the study’s five scales. Furthermore, Cronbach’s alpha coefficients were measured to determine the reliability and validity of the items contained in the scales; only highly dependable coefficients with values between 0.80 and 1.00 were reported. There were 416 respondents who completed the online survey and nine participants who participated in the mini groups. The findings revealed that students had both anthropogenic and ecologically-minded worldviews; they also had mixed reactions to the environment and environmental issues and were either exemptionalists or ecologically-minded. The participants were aware of environmental issues and of their behaviour towards the environment, despite some limitations. The respondents were, for example, unwilling to engage in public demonstrations to protect the environment, despite their strong involvement in the fallist movements of 2015/16 at South African universities. There is, therefore, a need to change their perceptions about the environment, especially with regard to protecting the environment. The results of the study do, however, show that there is potential to grow the environmentalism movement among students.
Environmental problems have a significant impact on humans in the same way that other social problems, such as crime, unemployment, and poverty do. The study revealed that some social issues such as crime, unemployment and poverty are considered more important than environmental issues, despite the intersecting nature of social issues with environmental issues; environmental awareness should thus be afforded the same level of recognition and importance. The findings also revealed that education plays a role in determining an individual’s level of environmental consciousness. Overall, the research confirmed some of the findings from previous similar studies. The findings confirm that the participants often do not understand the human-nature relationship. Environmental issues seem to be a low-level concern for most people, while social issues, such as unemployment, crime, and gender-based violence, are considered more worthy of governmental intervention. However, environmental issues need to be treated with the same level of urgency as other social issues, and young people should start to act as the voices of the environment.