Masters Degrees (Ecology)

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Community diversity and composition of ground-dwelling arthropods in major habitat types of the KwaZulu-Natal Sandstone Sourveld.
(2023) Mhlongo, Nokukhanya.; Tsvuura, Zivanai.; Munyai, Thinandavha Caswell.
Grasslands constitute over 25% of the global land surface and close to one-third of southern Africa. Natural and semi-natural grasslands are recognized globally for their high biodiversity value and their important contribution to the provision of ecosystem services, including provisioning services such as carbon sequestration, water catchments, and grazing for livestock and wildlife. Nonetheless, grasslands are consistently reduced and threatened by anthropogenic activities and invasive alien plants. Invasive alien plants may hinder the growth of natural vegetation by overconsumption of resources. The impact of invasive alien plants on natural vegetation may indirectly affect plant-to-animal interactions such as specialized pollination and seed dispersal syndromes which may ultimately disturb ecosystem processes. The Sandstone Sourveld in KwaZulu-Natal province of South Africa is a threatened grassland ecosystem as a result of various anthropogenic disturbances. Knowledge of arthropod response to differences in habitat types may be essential for an improved understanding of the structure and functioning of ecosystems, which is relevant for informing conservation practice. The aim of this study was to investigate the composition and diversity patterns of ground-dwelling arthropods (ants, beetles, Orthopterans, and spiders) in three habitat types (forest, intact grassland, and disturbed grassland) at Springside and Tanglewood Nature Reserves, which occur in the KwaZulu-Natal Sandstone Sourveld (KZNSS). The objectives were: (i) to document the response of the ground-dwelling arthropod community in different habitat types, (ii) to determine the impacts of seasonal change on the abundance and richness of ground-dwelling arthropods at the two sites, and (iii) to determine the correlation between the distribution of ground-dwelling arthropods and soil characteristics in the KZNSS. Ground-dwelling arthropods were sampled in Springside and Tanglewood Nature Reserves using pitfall traps in each habitat type. Soil parameters in the habitats were also assessed. Analysis of variance was used to test for differences in arthropod morphospecies richness and abundance across the habitat types and between seasons. The Shannon-Weiner diversity index was computed and used to compare the diversity of ground-dwelling arthropods between the two sites and among habitat types. Ground-dwelling arthropods showed varying patterns in response to habitat characteristics and the disturbance gradient at Springside and Tanglewood. Intact grassland was the most diverse habitat in both Springside and Tanglewood. In Tanglewood, the abundance of ants was greater in disturbed grassland which consisted of a variety of alien invasive shrubs, the high abundance was explained by the “intermediate disturbance hypothesis”. However, alien invasion showed more negative than positive impacts on the abundance and composition of ground-dwelling arthropods when there was a significant decrease in the abundance and composition of ants, beetles and spiders. Species richness of ants and beetles was higher in the wet than dry season whereas Orthopterans and spiders showed no significant difference between seasons. In all arthropod groups, a greater number of species were correlated to soil potassium, soil pH, and soil bulk density. Overall, the intact grassland had the highest species richness and abundance followed by the forest and lastly the disturbed grassland. The greater abundance of ants, beetles, and spiders in the pristine grasslands of KZNSS shows that there is still a need to conserve the remnants of the KZNSS vegetation. Therefore, the conservancy management is urged to consider the eradication of alien invasive plants. Future studies are recommended to consider the volant and vegetation canopy arthropods as they are all interdependent with ground-dwelling arthropods to form a whole community of arthropods in an ecosystem.
Importance of freshwater systems and eels in the uMngeni and uThukela catchments, KwaZulu-Natal, South Africa: community perspectives.
(2023) Nkomo, Mxolisi Nhlakanipho.; Downs, Colleen Thelma.
Globally, the conservation status of inland fishery resources and freshwater systems is vulnerable, threatening communities' livelihoods dependent on freshwater harvested species. Few studies have reported on the economic and cultural contributions of catadromous eels (Anguilla spp.) in southern Africa, particularly in South Africa. Beyond using freshwater systems for domestic purposes and meeting basic needs, people use rivers for socio-cultural purposes such as; cultural (cleansing), spirituality (healing), and religion (baptism). This study was undertaken to determine if human activities impact the African anguillids eel populations in the local communities of uThukela and uMngeni catchments and management areas in KwaZulu-Natal. A systematic review was conducted on global studies, with an emphasis on southern Africa, that report on the human perspective on the value of anguillid eels when in freshwater systems. In the southern African region, the available literature focused on the distribution of anguillid eels, habitat loss, and a report on the drastic decline of anguillid eels in KwaZulu-Natal's freshwaters where the Anguilla marmorata, A. mossambica, A. bengalensis, and A. bicolor occur. The studies from the northern hemisphere were rich in reports of eel harvesting (wild catches) and export, which was lacking in the southern African region. The systematic review showed a scarcity of knowledge regarding anguillid eels’ association with spirituality, spirituality, culture, and subsistence in South Africa. Secondly, people’s perceptions of the importance of eel species in freshwater fisheries were assessed using a questionnaire along water courses in the uMngeni and uThukela catchments and ecological management areas, KwaZulu-Natal. A total of 154 people were interviewed (66% males, 34% females); the majority of these participants were isiZulu-speaking, which contextualises the findings to the area of KwaZulu-Natal, uThukela and uMngeni management areas in particular. The fishing of eels was found in both catchments, with 74% (of the n = 102) being subsistence fishers (with only one female fisher), and 41% of these subsistence fishers specifically targeted eels. All the fishers that targeted eels depended on freshwater eel catches for income because of the relatively high demand and value. Some fishers caught and sold eels to traditional healers who used their products of medicinal products for different uses. Thirdly, the use of freshwater eels (Anguilla spp.) was assessed beyond harvesting them to sell or consume. In particular, using a questionnaire, the spiritual and cultural values of African freshwater eels and their associated freshwater environment in the uMngeni and uThukela catchments were investigated. A total of 154 people from different communities were interviewed along these river systems during 2021 and 2022. In the different communities within catchments, participants reported a number of different beliefs associated with eels and rivers. The responses showed that people valued clean rivers for various cultural, religious, and recreational activities. Some valued eels as they were associated with their beliefs. People who use freshwater for their respective cultural and spiritual, fishing, and domestic purposes voiced a considerable challenge in using freshwater systems, water pollution and water contamination from industrial waste or eutrophication from agricultural waste. Without community participation, there is no guaranteed sustainability of the water resources for the spiritual and cultural values of freshwater eels and freshwater systems. Community leaders and water management bodies must engage with communities in identifying important river uses (domestic, fisheries), and their contribution to spiritual and cultural practices. This will ensure long-term sustainable use and protection of inland water and fisheries resources associated with cultural and spiritual beliefs in KwaZulu-Natal. Freshwater eels hold a crucial aspect in the lives of traditional healers, some local fishers, and the general public, those that have knowledge of the use of these species. The study has shown that these species are still under-studied in KwaZulu-Natal, and most people have little understanding of the economic and cultural values, leading to less appreciation of these species by most people, mostly nonfishers.
Monitoring the efficacy of a lowland instream barrier on the lower uThukela River and the importance of river connectivity.
(2023) Van Zyl, Bradley Bruce.; Downs, Colleen Thelma.
Freshwater is the key to life on earth, with rivers being the pathway that allows it to run from mountains to the ocean, performing many important functions along its way. Humans rely on the many ecosystem services that freshwater provides, such as water quantity provision for domestic, industrial, and agricultural processes, food supply, water purification, and recreation and tourism, to name a few. Water-scarce countries, such as South Africa, are particularly vulnerable to water shortage issues and require many water supply solutions, like dams, weirs, and transfer schemes, to harvest the available rainfall. The uThukela River in KwaZulu-Natal is not only an important resource within its catchment but also to external catchments through inter-basin water transfer schemes, including that of the Thukela-Vaal transfer, which feeds the economically important hub of South Africa, the Gauteng Province. The lower uThukela River is a highly stressed system, with synergistic effects from multiple stressors relating to water quality, water quantity, habitat alterations, and wildlife disturbance affecting it. Additionally, the Lower Thukela Bulk Water Supply Scheme (LTBWSS) weir was recently constructed in its lower reaches, approximately 20 km upstream of the uThukela Mouth to the Indian Ocean, to provide bulk water to surrounding local municipalities. Due to the rich diversity of fish species in the region, particularly those with marine, estuarine, and freshwater migratory patterns, a fishway was incorporated into the design of the weir to facilitate fish movements over the weir. This study evaluated the impact that the LTBWSS weir has on fish community structures in the region and additionally assessed the efficacy of the fishway in allowing fish movements through it. Various sites were selected upstream, downstream, and on the tributary Mandeni Stream to assess environmental variables driving fish community structures, with passive and active sampling methods used to assess the fishway's functionality. Fish collection occurred at three sites upstream of the LTBWSS weir, four sites downstream of it on the uThukela River, and two sites on the Mandeni Stream. Abiotic variables relating to water quality, velocity, depth, and habitat were collected along with fish to determine which environmental variables were driving the fish communities at these sites. Multivariate analyses indicated that available substrate and cover, the average depth, and temperature were drivers of the fish communities in the study. Upstream sites showed lower species richness compared with downstream sites, with fish communities largely made of freshwater species and few euryhaline species. Additionally, individual species showed different responses to different environmental variables. Furthermore, since the construction of the LTBWSS, the loss of previously highly abundant cichlid species has occurred in the region. This is likely because of the synergistic effects of stressors created by it, such as the disruption of fine sediment transport, water abstraction, and pollution. Passive assessment of the fishway's efficacy in catering for migratory species used PIT telemetry. Budget constraints only allowed the installation of a single PIT antenna at the upstream entrance of the fishway, which was able to assess the upstream migration of fish from downstream. The results found that only eight individuals representing three species managed to navigate the fishway during the study successfully. This included Oreochromis mossambicus, Labeo molybdinus, and Clarias gariepinus. Active sampling involved electrofishing three key locations in the fishway on a monthly basis. Results showed that small-size classes of fish largely dominated the fishway and that the downstream entrance had the highest abundances and species richness. Further research on the role of the fishway in maintaining river connectivity is recommended. The outcomes of this study showed the importance that water resource managers have in maintaining the resource for humans and the environment. Knowing individual species' responses to environmental variables allows their populations to be better managed. Additionally, the outcomes of this study showed the importance of river connectivity past a barrier and highlighted the need for effective fish passage solutions in South Africa. It emphasised the need to better understand the migratory requirements of local fish to build better fish passage structures. Major stressors to be addressed include the impacts caused by barriers relating to flow releases, migration blocks, and habitat alteration upstream and downstream of them. Furthermore, the proper management of fish passage structures is essential to their functionality, which includes regular monitoring of the fishway for issues such as debris blockages and swiftly finding solutions to them to ensure that no undue delays or stress may occur for migratory fish.
Aardvark and people: can a shy species be widely known in a localised area?
(2022) Makwati, Nolutho.; Kraai, Manqhai.; Tsvuura, Zivanai.
The increase in human populations has led to humans sharing space with wild animals even in the natural habitats of the animals. Conflicts may arise when people and wildlife attempt to fulfill their needs which can be detrimental to one or both parties, and this type of conflict is called human-wildlife conflict (HWC). The human needs include people hunting wild animals for consumption of the animal and trading in animal body parts.Hunting is one of the factors that decreases populations of numerous animal species, and it occurs in many parts of the world e.g. in Africa, Asia and South America, where it contributes to extinction of species. The conservation and management of burrowing animals is a major challenge due to their elusive and nocturnal behaviour. The aardvark is an African medium-sized, burrowing mammal whose conservation status has not been updated recently due to the difficulties associated with studying nocturnal animals. Aardvarks may play a significant ecological role in the ecosystems in which they occur, such as by changing the landscape through their digging activities, or through affecting the dispersal of seeds. Therefore, the aim of this study was to explore the influence of humans on population trends and activity patterns of aardvarks outside protected areas, and to determine people’s perceptions about the animal. The study was conducted in Ncunjane village in Msinga Local Municipality, KwaZulu-Natal Province of South Africa. To understand people’s perceptions about aardvark in their community, I used a semistructured questionnaire survey. I asked personal information of the participants (sex, level of education and age), and questions related to people’s perceptions about the aardvark, such as people’s knowledge, myths, and their uses of the animal or its body parts. To determine activity patterns of the animal, I focused on aardvark foraging activities in a semi- arid savanna ecosystem that is also used as a communal rangeland over eight months between 2020 and 2021. I measured and quantified aardvark foraging holes using 53 50 m × 10 m transects where there was evidence of aardvark activity. In addition, I quantified aardvark burrowing of dens in the dry, wet and early dry seasons using walking transects guided by a research assistant who knows the area. I found that people have different perspectives about aardvark with the majority (78%) of respondents having strongly positive perceptions. The positive perceptions arise from aardvark not causing physical harm to people, and fleeing away upon sighting people. I found that aardvarks were mainly hunted for meat while some animal body parts were sold to traditional healers for traditional medicine. All seasons consisted of a greater number (> 51%) of old than new and very old foraging holes.The surface area of new, old, very old holes differed significantly with season (P < 0.0001) and the depth of new, old and very old holes also varied with season (P < 0.0001). In addition, the contents of foraging holes varied with age of the hole and season in that new holes lacked evidence of plant life across seasons. Aardvark dens were used by other animals such as spiders, wild cats, Cape porcupines and snakes. Hence, an increase in aardvark holes can be associated with significant landscape heterogeneity for vegetation and animal life. Aardvarks in Ncunjane fed close to their dens presumablyto mitigate against human predation through hunting threats, which may directly affect the extent of aardvark digging activities. These results show that aardvarks may be categorised as ecosystem engineers as the burrows provide shelter for other animals, also, their effects on other animals are disproportionate to their abundance. These results highlight that aardvarks are threatened by human uses and may decline in abundance in the area. Finally, aardvarks remain poorly studied in landscapes shared with humans. Further studies to assess aardvark numbers in human-dominated landscapes are required which can raise awareness and play a significant role in conservation of aardvarks.
The prevalence and implications of non-native wild boar Sus scrofa in KwaZulu-Natal, South Africa.
(2023) James, Claudette Njabulo.; Downs, Colleen Thelma.
Humans’ introduction of species into areas where they do not naturally occur has led to ecological and economic havoc. Introduced species can become invasive, exerting negative pressures on native species and the environment. Wild boar (Sus scrofa) is distributed worldwide except for Antarctica. The species is highly destructive and has been regarded as an invasive alien species in many parts of the world. Researchers have done many studies on wild boar investigating various aspects of the species, such as its biology, biochemistry, ecology, epidemiology, genetics, and archaeology. Invasive animals' effects on the environment and ecological systems were explored and focused on the impacts of exotic mammals, with wild boar as the species of interest. The potential for invasive spread by the European wild boar in South Africa was assessed by determining potentially suitable habitats using bioclimatic variables and the maximum entropy model, and then related to the present distribution records of the species in the country. Wild boars were found to have great potential to extend their invasive distribution range in South Africa. The prevalence of feral wild boar in KwaZulu-Natal (KZN) Province, South Africa, was investigated using camera trap surveys. The camera trap surveys revealed that there were no feral wild boar populations in the Midlands of KZN, but in other parts of KZN. The selling of wild boar in relation to the present legislation on wild boar in South Africa is illegal. The selling of wild boar contributes to the spread of the species in the country, as determined in this study. We recommend that the sale of wild boar should be monitored in South Africa by conservation authorities and the animals confiscated from the offenders and euthanised to prevent the further uncontrolled spread of the species. Moreover, we recommend the revision of the legislation regulating wild boar in South Africa to prevent the uncontrolled spread of the species in the country.
Assessing the trade of reptile species in the South African pet trade.
(2021) Mantintsilili, Asekho.; Downs, Colleen Thelma.; Shivambu, Tinyiko Cavin.; Shivambu, Ndivhuwo.
Despite the negative impacts that the pet trade has on the native and non-native biodiversity, economy and human health, the research suggests that the demand for pets and the extent of trade in live animals as pets has increased dramatically over the years. As a result, many species, including reptiles, have been translocated and introduced into new or non-native environments. Some of these have established feral populations, become invasive and are causing significant environmental and socio-economic impacts on non-native environments. Reptiles are among the most popular groups of animals in the pet trade industry globally. Trade in pet reptiles in South Africa is large and one of the major pathways through which non-native species, including invasive species, are introduced into the country. Despite this, little is known about the dynamics of the wildlife trade in pet reptiles globally. To understand the dynamics of the global trade in pet reptiles, we carried out a comprehensive literature search to gather relevant information from reptile pet trade-based publications. We further compiled a list of traded pet reptiles from all South African physical pet stores and online advertising websites to determine which species are traded, pose an invasion risk and have potential environmental and socio-economic impacts. We found a total of 39 publications based on the reptile pet trade from 1994 – 2021 worldwide. Our analyses revealed that the research effort was not uniform globally, with the majority (63.6%) of all relevant studies originating from three continents (Asia, Europe, and North America). Moreover, the United States of America (North America) and Indonesia (Asia) produced the greatest research outputs (12.1% each) compared with other countries across the world. We found at least 1140 reptile species belonging to 60 families involved in the global pet trade, with invasive red-eared slider Trachemys scripta elegans being the most frequently studied species (number of studies = 23/39). Of the recorded species, at least 79 are invasive, 46 endangered, 29 critically endangered, while only 546 are CITES-listed. In terms of reptile species sold in South Africa, we recorded a total of 2771 individuals representing 88 unique reptiles, 69 from physical pet stores and 18 from online advertising websites. KwaZulu-Natal, Gauteng and Western Cape Provinces had the highest number of pet stores and online advertising websites; therefore, they subsequently recorded the highest number of pet reptiles compared with other provinces. Physical pet stores were found to have the highest number of species compared to online trade. Of the recorded species, 76 are nonnative, and 15 of these are invasive to South Africa. Moreover, only 32 pet reptiles are listed under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). For current distributions, red-eared slider Trachemys scripta elegans, P. guttatus, and Western diamondback rattlesnake Crotalus atrox had the largest predicted climatic suitability. The future predictions for the latter two species were predicted to increase, while red-eared slider suitability shifted. Some species, such as Burmese pythons Python bivittatus, showed low invasion risk based on climatic suitability. However, given their large body size, history of invasion and their popularity in the pet trade, they are most likely to escape or be released from captivity and become invasive. A total of 76 reptile species were assessed for environmental and socio-economic impacts using the Generic Impact Scoring System (GISS), Environmental Impact Classification for Alien Taxa (EICAT), and Socio-Economic Impact Classification for Alien Taxa (SEICAT). Using GISS, we found that 13 species had environmental impacts (E_GISS), while 11 species had socio-economic impacts (SE_GISS). For EICAT and SEICAT, 13 species had environmental impacts, and eight had socio-economic impacts, respectively. The most popular pet species, red-tailed boa Boa constrictor, green iguana Iguana iguana, P. bivittatus, T. elegans, and central bearded dragon Pogona vitticeps had impacts in all the three scoring schemes. The later species and corn snake (Pantherophis guttatus) scored the highest for all impact schemes. Species sold in high numbers, with large climatically suitability and potential impacts, are more likely to establish feral populations and become invasive should they escape or be released from captivity. We, therefore, recommended that the trade in pet reptiles should be constantly monitored to avoid new introductions and the implications that the pet trade may have to the country.
Development and application of novel ornithological survey methods for the detection of cryptic avian indicator species that predict grassland health.
(2021) Beaumont, Stuart Nicholas.; Downs, Colleen Thelma.
The anthropogenic pressure on South African grasslands to meet the needs of the burgeoning human population has exposed them to extensive permanent transformation and degradation. Indicator species may identify changes in the grassland ecosystem. One such indicator species for natural sourveld grassland condition in South Africa is the red-winged francolin (Scleroptila levaillantii), whose population density is negatively correlated to grazing intensity and annual burning. Pointing dogs (Canis lupus familiaris) have been used extensively to aid ecologists in detecting these and other cryptic gamebirds to establish abundance. Here, a reliable method was developed to count cryptic gamebirds in the Greater uMgeni Vlei Expansion Area, KwaZulu-Natal Midlands, South Africa, where the route through a survey site was flexible. A variation to the existing distance sampling technique was proposed where the dog global positioning system (GPS) track was the transect line. The study investigated the effect of varying environmental conditions on the distance from which a pointing dog could reliably and consistently detect a bird and allow calculating a detection distance based on influential environmental variables. Between March – October 2021, using pointing dogs fitted with GPS devices, controlled and uncontrolled trials were conducted on Japanese quail (Coturnix japonica) and red-winged francolin in their natural habitat, respectively, to establish the environmental conditions that affect detectability and the detection distance from which a dog can detect a bird of known location. A total of 21 surveys were conducted (August 2020 – October 2021), on four survey sites by one or two pointer dogs fitted with GPS devices, to establish the population densities and territory of red-winged francolin. Individual area of search, established from the detection distance based on nominal wind speed and GPS track, was calculated. The redundancy in area of search enabled the evaluation of relative proficiency of detection of red-winged francolin. Of the environmental variables monitored, only nominal wind speed significantly influenced detection distance, where an increase of one-knot wind strength resulted in an increase in detection distance by 0.64 m. This enabled an area of search, considerate of influential environmental conditions, to be derived and the probability of detection within that search area = 1. Results showed significantly better precision and accuracy when surveying with two dogs when compared with one dog. The calculation of detection distance, where the probability of detecting a bird at this distance = 1, addresses the bias of varying scenting conditions. The established area of search, where the probability of detecting a bird within this area = 1, addresses the situation where known coveys in an area of known size remain undetected. Since the area of search is independent of time spent searching and normalised for redundancy, the bias introduced by varying physical aptitude is mitigated. Consideration for the application of this method should be given to the environmental conditions under which the surveying is planned since the detection distance function is derived for conditions at the present study sites. These techniques, based on a variable survey route through the survey site, may be used by citizen scientists to assist land managers, conservationists, and ecologists in establishing the abundance of red-winged francolin, contributing to burning and grazing regime management to enhance conservation efforts for the species.
Interactive effects of fire history and elevated 2 temperature on aboveground productivity in a high 3 altitude mesic grassland in South Africa.
(2021) Mvelase, Thembeka Ayanda.; Tedder, Michelle Jennifer.; te Beest, Mariska.
Abstract available in PDF.
Role and effects of wild southern African ungulates on seed dispersal of selected alien invasive plants.
(2021) Msweli, Lindelwa Sibongakonke.; Downs, Colleen Thelma.; Zungu, Manqoba Moses.
Abstract available in PDF.
Ant community responses to fertiliser application and disturbance in a mistbelt grassland, KwaZulu-Natal.
(2021) Khoza, Lindiwe Rebecca.; Munyai, Thinandavha Caswell.; Andersen, Alan N.
Abstract available in PDF.
The contribution of goats to household food security in selected communities of KwaZulu-Natal, South Africa.
(2021) Khowa, Anele Aurelia.; Kraai, Manqhai.; Tsvuura, Zivanai.
The growth of the human population in the world has been occurring at a rapid rate. This presents a challenge of how the world food demands will be met. These challenges are always felt the most in developing countries, and result in a lot of people in developing countries turning to alternative sources of income other than employment to manage their food situation. One of the alternatives includes a reliance on animal husbandry in order to meet and improve their livelihoods particularly with respect to food. Furthermore, small-scale farming of animals such as goats, sheep, pigs and chickens has also been an income source when the animals are sold. In developing countries, pastoralism and agro-pastoralism frequently occur among disadvantaged communities, who are often found in arid or semi-arid regions. As a result, goats have been shown to be an important type of livestock that can be kept in such conditions without financially stressing their owner by requiring constant care of supplementary feeds and medication. Goats are known for their resilience which allows them to cope with stressful conditions while being able to reproduce. This resilience and productivity of goats allows their owners to be able to liquidate them for cash if there is a need and also be able to slaughter them for their household consumption. Here, I investigated the contribution of small-scale goat farming to household food security in rural and peri-urban areas in KwaZulu-Natal (KZN), South Africa. The study was carried out in rural and peri-urban areas of Msinga, Kokstad, Howick and Pietermaritzburg in KZN. I used structured questionnaire surveys to determine the contribution of goats to household food security from the farmers’ responses. The questions asked related to the sale of goats (number, sex, age and sale value of the animal) and how the money generated from goat sales was spent. The study also determined goat sales from 27 households in three villages occurring in Msinga over a 2- year period of 2017 to 2018. I also assessed the participation of small-scale farmers in two livestock auctions, which took place in 2019 and 2020 by recording the age, sex, and coat-colour of the animals taken to auctions. The results obtained from the study showed that goats played a role in household food security as a source of cash as well as consumption in strenuous times. These findings of the study highlight that smallscale goat farming provides an alternative food source and income source for disadvantaged farmers. These findings were more prevalent in the rural areas, which kept more goats than those found in the peri-urban areas. Goats in rural areas ranged from 5 to 150 goats in a herd, and 5 to 50 goats in a herd while in periurban areas. Goats were a source of cash in numerous ways including sale of skins after slaughter that are used to craft household items such as stools that can be sold for cash. Adult goats were sold more at the farmers’ homesteads than auctions where buyers opted for younger goats. My results also showed that small-scale farmers use all possible avenues to sell their goats, as they sold a high number of animals from home and did not depend on infrequent livestock auction events. However, there were benefits derived from participating in auctions in terms of the relatively higher prices obtained there. For example, female and male goats sold for R2 177 and R1 268, respectively at auctions. The price was similar for females (R1 083) and males (R1 065) in homesteads. At auctions, female and male goats sold for R2 177 and R1 268, respectively. From homesteads, female and male goats sold for R1 083 and R1 065, respectively. Colour of goats proved to be an important trait at auctions as light-coloured goats were in higher demand than black goats. Homestead sales also remain a useful practice as farmers generate income to assist in day-to-day household expenses instead of waiting for infrequent auction events. Furthermore, small-scale farmers who plan to participate in auctions should pay attention to the characteristics (age, colour, and sex) of their animals when populating their herds. Sub-adult, light-coloured and female goats were the animals that were highly sought after at auctions.
Protected area management and planning challenges: sustainability and integrity – a cursory investigation of the role of the management plan.
(2021) Goosen, Magda.; Downs, Colleen Thelma.
Formally established protected areas in South Africa date back to the turn of the 19th century, yet requirements for protected area management plans only became mandatory approximately a century later. Before the promulgation of the Environment Conservation Act No. 73 of 1989 and subsequently the World Heritage Convention Act in 1999 and the National Environmental Management: Protected Areas Act 57 in 2003, requirements for management plans were voluntary, and guidance to its content was fragmented across various international, national and provincial policy instruments. There has been little academic debate on the relevance and content of protected area management plans to date and how such a long-term planning document can respond to emerging threats and opportunities. An improved understanding of these plans, and the role they play in biodiversity conservation, is required. The aims of this investigation were two-fold. The first was to gain insight into the challenges of effective management of protected areas, the long-term protection and sustainability of these areas, and, notably, the management plan’s role in addressing these challenges. The second was to evaluate the contribution and legislative weight that the management plan has in the efficient management, sustainable and ethical use, and long-term sustainability of protected areas within South Africa. Given that the above aims cover a potential insatiable field of research, this thesis was focused on the legal and policy framework for management plans and the management plans role in effectively managing these areas. Within this context, the following questions were addressed: ▪ What is the role of management plans in the effective management of protected areas? ▪ How does the legal and policy framework ensure that the derived plan is relevant and achievable and ultimately accomplishes the protected area purpose? ▪ What decision-making principles should be considered to facilitate sustainable and ethical use of protected areas, and what role does protected area management plans play in ensuring justifiable use of protected areas? ▪ What are the consequences when a long-term public-interest decision potentially isolates it from its transfrontier context, and what is the legislative weight of the management plan in mitigating such consequences? ▪ What role does the management plan, a long-term planning document, play in mitigating the impacts of or responding to immediate emerging threats and opportunities? It was found that despite being the principal legislative framework for management plans, the World Heritage Convention Act and the National Environmental Management: Protected Areas Act did not consolidate the plethora of management plan requirements for protected areas. As a consequence, the legislative provisions for protected area management plans were, in several instances, fragmented, conflicting and ambiguous. A consolidation of relevant provisions in these two statutes together with emerging best practice is, therefore, recommended. This consolidation may also provide greater clarity on the contemporary understanding of the contribution of protected areas to conservation and people’s well-being, i.e. it may entail a refurbishment of the ‘purpose’ of protected areas. Furthermore, the parallel evolution of the management of protected areas, the recreational use of these areas, and protected area management plans over the last century have brought about a complex relationship between these three aspects. Because of the fragmentation of legal and policy frameworks relating to these aspects, a need for a consolidated decision-making framework that provides for the basis for ethical and transparent decision-making could exclude inconsistent interpretations of legislation and policies. Incorporating such a decision-making framework in the protected area management plan can enhance transparency and accountability by the State or management authority to fulfil its fiduciary duty. Understanding of the above aspects was enhanced through a literature review and a case study of a development application in the area bordering the Tembe Elephant Park. The case study highlighted some of the potential consequences of a long-term public-interest decision that isolates a protected area from its transfrontier context and the role of an adaptive management plan in responding to these impacts and other current emerging threats and opportunities. A robust management plan remains the most relevant planning tool to address the complexities around protected area management and the fragmented legislative and policy frameworks for the effective management of protected areas in South Africa. Whereas management plans cannot be expected to cover explicitly every emerging circumstance – the principles included in such plans should provide the necessary guidance to decision-makers for unique circumstances and decision making.
Influences of bush encroachment and intensity on small mammals in a mesic savanna, Pretoria, South Africa.
(2021) Zwane, Thabile Jane.; Kraai, Manqhai.; Tsvuura, Zivanai.; Tjelele, Julius Tlou.
Abstract available in pdf.
Aspects of the urban ecology of the Spotted Thick-knee (Burhinus capensis)
(2021) Josiah, Kyrone Kent.; Downs, Colleen Thelma.
Abstract available in PDF.
Ecology of the South African giraffe (Giraffa camelopardalis giraffa) across a land-use gradient in central KwaZulu-Natal, South Africa.
(2020) Nyathi, Memeli Jefrey Jethro.; Downs, Colleen Thelma.; Calverley, Peter Markham.
Abstract available in pdf.
Parthenium hysterophorus distribution and efficacy of control in Hluhluwe-Imfolozi Park, northern KwaZulu-Natal.
(2020) Mbatha, Sethabile Khwezi.; Tedder, Michele Jennifer.; Carbutt, Clinton.; Mutanga, Onisimo.
Abstract available in pdf.
Impacts of foraging behavior [sic] by Cape porcupines and their effects on nutrient cycling in mesic savannas.
(2021) Kraai, Unathi Masiobi.; Tsvuura, Zivanai.; Kraai, Manqhai.; Mkhize, Nthuthuko Raphael.; Mgqatsa, Nokubonga.; Tjelele, Julius Tlou.
Through feeding and associated activities, herbivores play a major role in determining the structure of savannas. The Cape porcupine (Hystrix africaeaustralis) is a semi-fossorial, large (ca. 12 kg) herbivorous rodent with a generalist foraging strategy that feeds on plant parts occurring above- and below ground. Subterranean foraging by porcupine may influence biotic and abiotic processes in that area. The extent of soil and vegetation perturbation may be pervasive on the landscape so that these animals may be considered as ecosystem engineers. The digging activities of ecosystem engineers are significant as they influence soil properties (e.g. nutrient cycling) including germination of trapped seeds and establishment of seedlings. These changes may occur at small and large scale on a landscape. The utilisation of woody vegetation and ecosystem engineering by such animals, particularly by shy and nocturnal species, is understudied in African savannas. The study was aimed at: (1) quantifying the extent of herbivory by the porcupines on target trees during the wet and dry season in three mesic savanna sites, and (2) evaluating the effects of Cape porcupines’ digging on nutrient cycling (total carbon and total nitrogen) and quantify establishment of vegetation on the mounds. Sampling was undertaken at three mesic savanna sites in South Africa: (i) Roodeplaat Farm in Gauteng Province; (ii) Goss Game Farm; and (iii) Bisley Valley Nature Reserve, both in KwaZulu-Natal Province. I used 30 m × 30 m plots to quantify porcupine foraging holes and bark damage on adult trees at Roodeplaat and Goss while 10 m × 10 m plots were used at Bisley where porcupines foraged on seedlings and saplings of woody plants. I also collected porcupine dung samples over the dry and wet season for micromorphological examination of porcupine diet. I collected soil samples from the mound soil of foraging holes and from adjacent locations within 0.5 m of the hole for analysis of amounts of total carbon and total nitrogen. Measurements of foraging holes comprised of two perpendicular diameters on the soil surface and the maximum depth. Porcupines utilised different tree species of various sizes at the three sites while targeting specific parts of these trees. At Roodeplaat, porcupines targeted Vachellia robusta on which they consumed the trunk part immediately below ground, whereas at Bisley, roots and the lower trunk of V. nilotica seedlings and saplings were utilised, also through digging holes while the bark of the lower trunk (up to 0.7 m) of Spirostachys africana trees was stripped off at Goss. I found that 70% of young V. nilotica trees in or adjacent to holes in Bisley were scarred or destroyed as a result of porcupine feeding on them, while 16% of S. africana trees were wounded at Goss. Only 7% of V. robusta trees were damaged at Roodeplaat. In Bisley, I found that grasses and forbs established faster on the mound than on the surrounds, i.e. seedlings germinated first on the mound than the adjacent not disturbed soil. I also found that foraging holes provide shelter to other animals especially those from the arthropod group e.g. spiders. Amounts of total carbon and total nitrogen were similar between the mounds and undug soil. These findings are discussed in terms of nutrient cycling through digging, breaking down of plant parts and herbivore-induced mortality of main tree species. I argue that tree thinning from ringbarking by porcupine through their foraging activities ameliorates woody plant encroachment in mesic savannas.
Effects of increased temperature on growth and nutritional value of mesic grasslands, with or without woody legume seedling competition.
(2020) Gili, Nikilita.; Tedder, Michelle Jennifer.; Scogings, Peter Frank.; Mkhize, Nthuthuko Raphael.
Mesic grasslands are complex ecosystems covered in grasses and other graminoid vegetation. The species composition varies due to variation in rainfall and temperature; these grasslands are climatically supported. They also vary in nutritive value and grasslands with high species richness have low nutritive value because grasses differ genetically. Grasses’ response to high temperature and competition is species dependent. Grasslands are ideal for ecological experiments because grasses grow fast and their response to environmental changes is noticeable. Therefore, an experiment of induced warming with legume seedlings interaction was conducted at the University of KwaZulu-Natal, using open top chambers and Vachellia sieberiana var. woodii. This was done to determine the effect of increased temperature on the biomass, growth, morphology and nutritive value of Themeda triandra and Aristida junciformis. These species were chosen because they occur naturally and dominate in the Ukulinga farm, where the experiment was conducted. They also have contrasting palatability, T. triandra is highly palatable and A. junciformis is less palatable. Vachellia sieberiana seedlings were grown from seed and transplanted after two months to the field to interact with grasses for four months. The results suggest that the interaction of warming and woody seedlings reduces the biomass of the investigated species. This implies that warming reduces grass biomass. Plant traits such as grass height, leaf area, tiller width and tuft diameter responded differently to the treatments. The fibre (neutral detergent fibre) of T. triandra was increased by warming. The interaction of warming and woody seedlings had no effect on the regrowth fibre content. The interaction of warming and woody seedlings increased the protein content of A. junciformis. Warming and woody seedlings independently increased the protein content of T. triandra. The response of plants to increased warming will help ecologists understand the effects of global warming. To provide more insight into these findings, further research on specific species with longer experimental duration and high woody seedling neighbour density is of importance.
Fleshy-fruited invasive plant species in KwaZulu-Natal, South Africa: native avian seed dispersal and impact assessment.
(2019) Bitani, Nasiphi.; Downs, Colleen Thelma.
Globally, alien plant species have been recognised as a major threat to biodiversity. The increased global trade and travel have resulted in the increased introduction of new species. Direct or indirect introductions of alien invasive plant species result in altered ecosystem functioning, negatively affect economies, human health and wellbeing. In forest systems, habitat fragmentation has major impacts on biodiversity including the facilitation of alien invasions. Habitat alteration creates disturbance zones that are associated with increased invasion success. South Africa, like other parts of the world, is severely affected by alien plant species. Fleshy-fruited invasive species are amongst the most damaging invasive species with major environmental, social and economic impacts. Fleshy-fruited invasive plant species integrate into local seed dispersal networks and form mutual relationships with local avian seed dispersers leading to increased invasion potential. The success of avian mediated seed dispersal is influenced by the functional traits of both the plant and avian seed dispersers. Considering the negative impacts of fleshy-fruited alien invasive species it is important to understand ecological processes leading to their successful spread and if high priority species are being targeted for management to guide policy and conservation. Understanding avian mediated dispersal is important as it gives insights into the species that could promote alien plant invasion. The aim of the present study was to assess avian seed dispersal, and ecological and socio-economic impacts of fleshy-fruited alien invasive plant species. The objectives were to (1) predict avian seed dispersers of fleshy-fruited alien invasive plant species; (2) determine the assemblage of native avian species potentially dispersing the seeds of Lantana camara; and (3) determine the socio-economic and ecological impacts of fleshy-fruited alien invasive plant species. Firstly, we predicted the avian seed dispersers of fleshy-fruited invasive plant species in the Indian Coastal Belt Forest of KwaZulu-Natal Province, South Africa using functional traits of avian species (body mass, gape width, bill length, degree of frugivory, foraging strategy, abundance and habitat specificity) and fleshy-fruited invasive plants (crop size, fruit size, seed size, number of seeds, plant height, plant habitat, fruiting period and derived invasiveness score). The results showed that small, abundant forest generalist avian species were potentially effective dispersers of fleshy-fruited invasive species. Fleshy-fruited invasive plant species that were more likely to persist in the disturbed Indian Coastal Belt Forest through avian-mediated seed dispersal were small-seeded, open habitat plants with relatively longer fruiting duration. Secondly, we assessed the role of native avian species in the potential dispersal of a highly invasive shrub Lantana camara of the family Verbenaceae in Pietermatzburg, KwaZulu-Natal, South Africa. Avian species visiting L. camara were observed and potential dispersal distances estimated. The results showed that native avian species were potential seed dispersers of L. camara were mostly relatively small, moderately frugivorous avian species. The dark-capped bulbul (Pycnonotus tricolor) showed relatively high visitation frequencies to L. camara and was more likely the main effective dispersers of the plant. Potential seed dispersal distances were shown to range from 9 to 45 km and long distance seed dispersal distances were shown to be rare and only limited by rarely large avian frugivores. Lastly, we assessed the ecological and socio-economic impacts of fleshy-fruited invasive species using the generic impact scoring system. The results showed that fleshy-fruited invasive plant species have both socio-economic and environmental impacts. The highest environmental impacts were shown to be on ecosystem and vegetation, or plant and the highest socioeconomic impacts were on agriculture, forest production and human health. The results presented in this thesis provide essential insights into the importance of avian mediated seed dispersal in the invasion of fleshy-fruited invasive plant species. The findings of the study also highlight the importance of predictive approaches in informing the management of invasions and showed fleshy-fruited invasive plant species with high socio-economic and ecological impacts. Knowledge of species with high impacts will help in guiding resource allocation and preventing the introduction of high-risk species. Also, ecologists and other decision-makers should consider ecological processes that are leading to the spread of invasive plant species in management practices or plans.
Assessment of the current ecological integrity of the uMngeni River, KwaZulu-Natal, South Africa, using fish community structures and attributes of the Labeobarbus natalensis (Castelnau, 1861) populations.
(2019) Dlamini, Pumla Vanessa.; Downs, Colleen Thelma.; O'Brien, Gordon Craig.
Rivers are the main source of freshwater water for human communities and provide people with numerous ecosystem services such as water purification, transportation, power generation, food supply, and water for domestic, agricultural and industrial use. Water resources, and the ecosystem services they provide, are particularly important in developing countries, such as South Africa. The uMngeni River, is a strategic resource that provides water to two of the largest cities in KwaZulu-Natal Province (the uMgungundlovu and eThekwini municipalities), with more than four million people, making it socio-economically important. As such, to maintain sustainability the protection of the river is important. However, in South Africa and KwaZulu-Natal, the impact of anthropogenic activities has made riverine ecosystems one of the most threatened types of ecosystems in the world. The use of fish as key indicators of the ecological state of aquatic ecosystems is well established as their vulnerability to environmental change, mobility, longevity and relative ease of species identification make them good indicators. This study evaluated the current ecological integrity of the uMngeni River in KwaZulu-Natal using multiple lines of evidence including fish communities and the state of Labeobarbus natalensis (the KwaZulu-Natal yellowfish) populations, and environmental variables. The research was undertaken in the major man-made lakes (dams) in the uMngeni River (namely Midmar, Albert Falls, Nagle and Inanda Dams) and in the rivers of the uMngeni Catchment. Abiotic lines of evidence investigated included water quality and habitat, while the biotic lines of evidence included fish community structures and attributes of the population of L. natalensis. Fish community structures at eight selected River Eco-status Monitoring Programme (REMP) sites in the uMngeni catchment were considered. This included consideration of how the fish communities responded to changes in a range of environmental variables and alien fishes using the Fish Response Assessment Index (FRAI), we were able to determine that the ecological integrity of the uMngeni River decreases in a downstream gradient from the upper reaches of the catchment to lower reaches, due the synergistic effect of multiple anthropogenic stressors. The multivariate analyses indicated that the anthropogenic impacts responsible for shifts in fish community structures, and the associated ecological integrity of the river were related to changes in instream habitats and water quality stressors primarily. Most of the environmental changes identified can be linked to flow modifications and land use activities throughout the uMngeni catchment. Assessments of attributes of the L. natalensis populations from large instream impoundments in the uMngeni River (namely Midmar, Albert Falls, Nagle and Inanda Dam) resulted in diminishing wellbeing of the populations of this endemic migratory fish progressively both in abundance and structure, down the length of the catchment. The quality and quantity of water diminished down the catchment gradient with this gradient and the effect of the barriers themselves can partially be attributed to the impaired state of the populations. Impoundments are not preferred by juvenile and young L. natalensis that prefer shallow riffle habitats that are lacking in dams, the occurrence of many predatory alien fishes in the dam can also be attributed to the absence of small yellowfish in the dams. The outcomes of this study can contribute to the sustainable management and development of conservation plans for the rivers and dams in the uMngeni catchment. Major stressors that should be mitigated include the barrier effect and operation or flow releases from the large dams and smaller weirs etc. that cause river fragmentation in the catchment. It is recommended that management plans for the conservation of the fishes in the catchment should be developed which is achievable as the current supply of resources in the catchment is balanced with the demand for use. Fish passages should be established in all of the dams in the uMngeni River to allow migratory fish free passage along the river and to re-establish river connectivity processes. Additionally, the removal of redundant weirs or partial man-made barriers is recommended to alleviate the effects of fragmentation particularly on the yellowfish in the catchment. More research is required to understand the migratory requirements of fishes in the catchments and the cost-benefit of mitigating river fragmentation to achieve a sustainable balance between the use and protection of resources in the catchment. Finally, the study has identified water quality and flow stressors that are negatively affecting the wellbeing of the fish communities in the catchment. The water quality stressors derived from land-based activities and associated management of flows in the catchment must be improved to attain a sustainable balance between the use and protection of the resources of the uMngeni Catchment.

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