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Item Embargo Role of bats as natural pest control agents of moth pests (false codling moth and carob moth) on citrus orchard(2024-09-06) Khavheli, Thivhileli; Swanepoel, L. H.; Foord,S. H.Over the years, the change in farming practices has caused a tremendous decline in the diversity of flora and fauna within agricultural landscapes through intensification of land use. An increase in agricultural intensification has resulted in increased farm sizes and reduced landscape heterogeneity. In the past two decades, the interest in services that insectivorous bats provide within agricultural landscapes through insect pest suppression has gained recognition globally. Multiple studies have thoroughly examined the vital role played by insectivorous bats within agricultural landscapes as biological control of insect pests for crops such as rice, cotton, pecan, corn, and macadamia. However, little to none is known about the impact insectivorous bats have within citrus landscapes. This study specifically focuses on how insectivorous bats inhabiting different landscapes respond to insect pest outbreaks, especially that of false codling moth (FCM) and carob moth (CM), important pests of citrus. The study first gives a general introduction of the importance of landscape heterogeneity within agricultural landscapes, beneficial effects that insectivorous bats have in agricultural areas, and the use of advanced molecular methods to analyze the diet of insectivorous bats. Secondly, we investigated the influence of land use heterogeneity, temperature, and insect pest activity on bat species richness and different foraging groups. Our results demonstrate higher bat activity in natural areas (wet riparian zones and orchard edges) compared to orchards, and further illustrate that bat species richness and activity were highly influenced by temperature. Lastly, we investigate the moth pest consumption by different bat species of different foraging groups. We found that all bat foraging groups, open-air and clutter-edge foragers, had a high consumption rate of agricultural pests including FCM and CM. The results of this study emphasize how crucial it is to preserve natural habitats and bat populations in citrus landscapes. Including bats in integrated pest management (IPM) programs can benefit both agriculture and biodiversity.Item Embargo Ecology and phenology of Melia Azedarach Linn.on and off the Riverine Areas(2024-09-06) Masia, Khathutshelo Victor; Ligavha-Mbelengwa, M. H.; Mokganya, M. G.Noteworthy, Melia azedarach Linn. is an indispensable tree species that is utilised in various forms. It can be used in craft industries as a substitute for teak wood when the supply is reduced. Simultaneously, its leaves, roots, bark, and flowers are used as medicines and natural pesticides. Melia azedarach Linn. is traditionally used as medicine to treat astringents and furthermore can be used against intestinal worms, skin diseases, stomachaches, uterine illnesses, and as a diuretic and febrifuge. In addition, it has been reported to possess anticancer, antimalarial, analgesic, and anti-inflammatory, antifungal, antibacterial and antioxidant activities. This tree can adapt to different environmental conditions so that it can grow well in extensive areas. Melia azedarach Linn. is a plant that grows both on and off the riparian zones. Communities in South Africa see less value attached to it to the extent that in many places where these trees are found growing, the majority are cut for no good reason. Sometimes, the plant species is cut for the construction of fences, kraals, or firewood. The main reason for this practice is that much is not known about the plant; it could be found de-vegetated anytime. The study was conducted at Ha-Tshikonelo, Thulamela Local Municipality, Limpopo Province, South Africa. Plant phenology and distribution have gained increased interest because climatic change is sensitive to phenological traits and their consequences for ecosystem function. It is made possible to gather information on spatial and ecological scales because of new technologies innovative technologies. Temperature, photoperiod, and winter chilling are examples of plant phenology drivers, and competition is included. A smartphone ( Huawei Nova Y60) camera was used to take pictures of phenological changes when visiting the on and off riparian zones from August 2019 to December 2021. The research aimed to determine the different phenophases and distribution patterns of Melia azedarach in riparian zones. The Nearest-neighbour method of sampling individuals within a population of plants was used for data collection. The collected data was then analysed using Analysis of Variance (ANOVA). It was found that Melia azedarach Linn. is regularly distributed for both on and off-riparian areas. Phenophase occurring off riparian zones was found to be occurring earlier than in riparian zones. It was found that Melia azedarach Linn. is surviving and flourishing in both off and on the riparian zones. On riparian zone individuals were growing bigger than those found off the riparian zones because of the abundant supply of resources such as water and nutrients.Item Embargo An analysis of exposure and slope gradient impact on tree layer profile of Maroelakop vegetation in Nylsvley Nature Reserve, Limpopo Province, South Africa(2024-09-06) Mavhila, Tendani; Tshisikhawe, M. P.; Magwede, K.Since the 1850s, plant ecologists have been eager to investigate challenges in vegetation communities that are related to slope. The aspect of the slope is crucial in terms of the diversity and distribution of plants. This research was conducted on Maroelakop Mountain within Nylsvley Nature Reserve located in Mookgopong, Limpopo Province. The investigation aimed to assess and contrast the vegetation composition on the north-facing slope with that of the south-facing slope. The specific goals included ascertaining the density and frequency of dominant tree species on each slope, calculating the importance value indices of trees on both slope gradients and analyzing the population structure of the slope gradient. Point Centred Quarter (PCQ) was used in data collection. Shannon-Weiner diversity index, Simpson diversity index, and Evenness index were used to measure plant species diversity. In this study, a total of 600 trees were discovered and identified by their botanical names. The data represented 21 plant species in 17 genera and 12 families. The tree layer of the north-facing slope was dominated by Diplorhynchus condylocarpon, whereas that on the south-facing slope was dominated by Burkea africana. Both tree species had high-importance value indices. Shannon diversity index of 2.20 was obtained for the North-facing downslope, whereas the South-facing downslope had 1.74. The average Simpson diversity index for the North-facing slope was 0.82 and South-facing slope 0.77. The average Evenness index for the North-facing slope was 0.93 and, on the South-facing slope 0.81. This study concluded that Diplorhynchus condylocarpon is the most prevalent species within Maroelakop Mountain in the Nylsvley Nature Reserve.Item Embargo Effects of anthropogenic factors on the population structure of Pterocarpus angolensis DC in a communal area of Khalavha Village in Vhembe Biosphere(2024-09-06) Ndou, Tshihumbudzo; Tshisikhawe, M. P.; Mashile, S. P.Pterocarpus angolensis DC. is an indigenous species of value across Africa. The species have been identified as having a high utilization rate for different purposes. The purpose of the study was to analyze the population structure of P. angolensis, a species in high demand. Ethnobotanical information was collected with an aid of a questionnaire from fifty-three informants. The informants identified two plant parts preferred by the community. The only preferred parts are stem (67%) and bark (33%). The study identified a lack of indigenous knowledge of the species amongst the youth. Some of the uses reported on P. angolensis were firewood (n=33), medicine (n=43), craftwork (n=35), protection (n=16), and timber (n=4). The transect sampling technique was used to document ecological data on the species to analyze its population structure. Fifty-three transects of 100m x 10m were constructed within the population. Ecological parameters recorded included stem diameter, height, and crown health status. Basal stem diameter data recorded on P. angolensis sampling were grouped into seven size classes and displayed an inverse J-shaped curve when analysed. The study showed that the population had more individuals (n=60) within the seedlings size class (0-5cm) when compared to the bigger size classes (20.1-25cm, 25.1-30cm, and >30.1cm). The majority (37%) of P. angolensis individuals had light crown damage which depicts on average an aspect of healthy crowns. Only 1% of sampled individuals had dead crowns. Monitoring of the P. angolensis population will assist in making sure that it stays healthy and viable.Item Embargo Fruit bat diet, foraging ecology and seed dispersal in the Vhembe Biosphere Reserve.(2024-09-06) Mphethe, Vusani; Swanepoel, L. H.; Taylor, P. J.; Parker, D.; Weiner, S.Agricultural intensification, and a rapid human population growth have resulted in increased human wildlife contact. In the case of fruit bats, conflict with commercial fruit farmers has been a leading contributor to a decline of bat species populations, despite the vital ecosystem service of seed dispersal provided by fruit bats. Conflict between fruit bats and fruit farmers often stems from perceived or actual damage to their crops, especially during the harvest season. Such conflict often leads to the persecution of fruit bats, either legally or illegally. Therefore, a proactive assessment of bats diet in agroecosystems is important. South Africa is one of the major producers of litchi and its litchi industry is well established and continues to grow. This study provides insight into the diet, foraging behavior, and ecosystem service of seed dispersal of fruit bat species in litchi orchards and natural habitats to advise on management strategies on how to reduce crop damage. It also assesses crop raiding by fruit bats and other crop raider animals, and their activity patterns in response to litchi abundance during the harvest season using camera traps. This study also used a vertebrate exclusion experiment to quantify the effect of excluding crop raiders on yield, as well as a questionnaire survey to quantify the perceived damage in litchi orchards. The study was conducted in the subtropical fruit growing area of Levubu and the natural habitats of the Soutpansberg, Limpopo province, South Africa. An introduction to the order Chiroptera and important fruit bats ecosystem service of seed dispersal as well as the disservice of crop depredation in agroecosystems is provided in Chapter One. Chapter Two, bats were captured with mist nest in both agricultural and natural habitats during the litchi pre-harvest and harvest seasons. We sampled the litchi orchards as well as natural habitats from February 2018 to November 2020 and used GIS and R (ggplot2, iNEXT, lme4) to analyse fruit bats diet, their effect on seeds germination and habitat use with respect to litchi fruit abundance. Results show that fruit bat diet was dominated by wild fruit species (95%) during the litchi harvest season (December) when fruit bats are perceived to be feeding on litchi fruits. Ficus (Ficus spp.) seeds collected as fruit bats spit-out seeds had significantly lower germination rates than regular seeds, but a significantly lower germination latency, and a similar pattern was also observed for quinine tree (Rauvolfia caffra). Our results suggested that fruit bats inhabiting litchi orchards and surrounding natural vegetation feed primarily on wild fruits due to the high percentage of natural vegetation in our study area, which support the importance of natural orchard edges in mitigating crop raiding. Chapter Three, we mounted 10 camera traps (from October 2019 to December 2020) on two litchi orchards for assessing fruit bats and other crop raider animal species richness and activity patterns in response to litchi abundance during litchi harvest season. Six time-triggered canopy camera traps were mounted (6m above the ground) to monitor the animals visiting litchi tree canopies during litchi pre-harvest (October/November) and harvest sessions (December). Additionally, four motion-triggered camera traps were mounted 30 cm above the ground to monitor animals visiting the litchi trees at the ground level. We used Digikam software to tag images and R (ggplot2, iNEXT, lme4, overlap, RSQLite) to analyse species richness, Relative abundance Index (RAI), and crop raider activity patterns. We recorded a significantly higher species richness index during the harvest season (December) compared to litchi pre-harvest season (October/November). Crop raider species richness was lower compared to incidentally observed species during the litchi harvest season. Fruit bats (which could not be assigned to either Epomophorus or Rousettus genus) recorded lower activity (RAI (of 2.49) compared to Dark-capped Bulbul (Pycnonotus tricolor; RAI (43.44)). Lastly, fruit bats did not show/exhibit any change in seasonal activity between the litchi pre-ripe and ripe seasons. As reported in Chapter Four, we collected the litchi yield data on both vertebrate exclusion trees (caged) and paired open control trees during the December/January harvest season between 2019 and 2020, to quantify the effect of excluding crop raider vertebrates, weather, and insect damage on yield. We constructed a total of six vertebrate exclusion cages on two litchi orchards, each enclosing one litchi tree and paired them with open control trees marked with a tapper. Additionally, a questionnaire survey was conducted in Chapter Four from both commercial and small-scale litchi farmers to quantify the perceived damage caused by crop raiders and later compared the results to the total yield for trees inside the exclusion cages and paired open control trees. Our litchi yield results show that open control trees produced significantly higher yield than caged trees, which is contrary to our hypothesis. There was also a weak but non-significant trend towards higher vertebrate damage on control trees compared to caged trees. Questionnaire survey results revealed that weather (sun/rain) and monkeys were the main cause of damage in litchi orchards, when compared to fruit bats, and there was a strong agreement among farmers that the damage varied by vertebrate groups. Farm type (commercial versus small-scale) also show statistically significant difference in the perceived damage caused by bats, birds, insects, monkeys, weather and wild pigs. The results of our study also show lower crop raiding incidence were reported for fruit bats. In summary, Chapter Five concludes that fruit bats prefer to feed on wild fruits over commercially cultivated fruits such as litchi, and potentially provide ecosystem service of seed dispersal, and that remnant natural vegetation at the orchard edges are important food sources, and assist in mitigating crop raiding, and need to be maintained or restored. The study also shows that fruit bats are not crop raiders of litchi fruits, and do not change their seasonal foraging activity in respond to litchi abundance during the litchi harvest season, as believed by farmers. However, further research on fruit bats crop raiding must be conducted in an area with known abundance of colonial species like Rousettus aegyptiacus, a known global pest of litchi crop. Additionally, the use of radio tracking should be considered, and could provide insight into fruit bats habitat use. Our study further revealed that vertebrate exclusions did not increase litchi yield, and that weather and monkeys were the main cause of damage when compared fruit bats. As a result, this study provides information to farmers on fruit bat`s important ecosystem service of seed dispersal and the benefit of maintaining natural orchard edges.Item Embargo The physiology of sprouting and its ecological implications for Savanna woodland and dynamics in the Nylsvley Nature Reserve, Limpopo Province, South Africa(2024-09-06) Ligavha-Mbelengwa, Maanda Hadzhi; Ogola, J. B. Ochanda; Tshisikhawe, M. P.Disturbance in its various forms is an integral component of any ecosystem, and it contributes significantly to the patterning of the vegetation. Many savanna plant species survive disturbance, such as cutting or clipping, through resprouting. Sprouting is important, particularly in situations where chances for the establishment of seedlings is rare. High disturbance intensity suppresses plant recovery, while low disturbance intensity stimulates plant regrowth. Disturbing plants frequently depletes stored carbohydrate reserves which are indispensable for regrowth, while disturbing plants less frequently allows plants space to accumulate root carbohydrate reserves. Savanna plants in game reserves are usually exposed to disturbance in the form of grazing, browsing, accidental fires, and competition. It is necessary to comprehend how savanna plant species respond to the disturbance for the sustenance of the life of the game in those ecosystems. This study assessed how savanna plants (i) respond to cutting, (ii) relate to bark thickness, stem diameter, and fire, and (iii) respond to release from competition. Chapter 3 of the current thesis experimented on juveniles of the two savanna plant species, namely Dichrostachys cinerea (D. cinerea) and Terminalia sericea (T. sericea), and Chapter 4 experimented on seedlings and juveniles of the same two savanna plant species referred to in chapter 3. Juvenile individuals that were utilized for experimentation in chapter 3 were not the same as those utilized in Chapter 4. Dichrostachys cinerea (D. cinerea) and Terminalia sericea (T. sericea), were subjected to clipping. In one instance, a group of juvenile plants per species was cut seasonally during the first year of experimentation for the whole experimental period, while in another instance, seedlings and juveniles were cut; the responses of plants were monitored and compared in both instances. Clipping of individual plant species monthly in the year simulated how seasons differentially affect plants' responses to cutting. The study was carried out for two and half years. The heights of cut plants were compared to establish how the plants responded to clipping. The heights of the plants were measured in both instances only towards the conclusion of the experiments. The bark thickness, and stem diameter of plants of different age groups were measured using Vernier callipers and diameter tapes, respectively. Gaps created between grass plants were measured pre- and post-removal of their potential competitors. All the individual plant species that were clipped anyhow survived clipping throughout the experimental period. Winter-clipped plant species generally outgrew plants that were clipped in other seasons, probably due to ample carbohydrate root reserves during this season of the year. Juveniles grew faster than seedlings in terms of height when both were cut at the same time of the day, presumptively due to more carbohydrates in their roots than in those of the seedlings. More seedlings died than juveniles when both were exposed to the same fire intensity. We found root reserves affected differentially between seasons of the year. The bark thickness increased with plant age and height to about 50 cm in trunk circumference; thereafter, the relationship was inconsistent. Openings that resulted when grass plants competed for resources such as moisture became readily available for invasion by new plant species, mainly alien plants. Managed disturbance is thus important and necessary to maintain ecosystems in balance. Communities should thus be educated on how savanna ecosystems respond to disturbances at different seasons of the year to mitigate situations where our savanna ecosystems could be converted into ecosystems that are not suitable for savanna games.Item Open Access The phenological study of Securidaca longepedunculata, in the Nylsvley Nature Reserve, Limpopo Province, South Africa(2023-10-05) Mukhithi, Aluwani Godfrey; Ligavha-Mbelengwa, M. H.; Magwede, K.Phenological observations were conducted through analysis of phenological phases and stages of 200 sampled S. longepedunculata plant individuals in the sandy soil areas of Nylsvley Nature Reserve, Limpopo Province, South Africa. Phenological stages comprised of onset, peak development and decline; while phenological phase is time spent by those stages for example leaf yellowing (Ruml and Vulic, 2005). Phenological phases patterns were analysed by focussing on vegetative and reproductive phenophases. Vegetative phenophase considered the presence of budding and developmental stages of leaves until they are shed. Reproductive phenophase considered the presence of flowering and developmental stages of fruits until they are shed. Phenological data was mainly collected through direct ground based observation. The results showed that budding, leaf greening and flowering were observed from mid spring in September in response to upcoming summer which is warmer and rainy. Ripe seeds and leaf yellowing were predominantly visible in autumn and winter respectively, as they are in their annual maturity stage. Leaf and seed shedding were observed at their peak development from late winter in June to early spring in August, probably due to the effect of windy conditions on site. Changes in the phenology of S. longepedunculata plant individuals caused by environmental changes resulted in changes at the community level. This shows that thorough phenological pattern monitoring is essential in order to forecast plant species behaviour. Also, it is necessary to provide knowledge on proper management of the reserve and protection of the plant species.Item Open Access Thermal biology of the two-spotted stink bug, Bathycoelia distincta (Hemiptera: Pentatomidae) a major pest of macadamia(2023-10-05) Muluvhahothe, Mulalo Meriam; Foord, S. H.; Joubert, E.The physiological functions of insects are mainly dictated by temperature because they rely on the external environment to regulate their body temperatures. This temperature dependence drives their performance, with profound implications on abundance and distribution. Daily environmental temperature fluctuations may outpace an insect’s thermal tolerance capacity, which requires physiological plastic mechanisms to survive. In the context of global warming, insects may be vulnerable to temperature variations, and may ultimately determine their population dynamics. The two-spotted stink bug, Bathycoelia distincta (Distant) (Hemiptera: Pentatomidae) is an important pest of macadamia in South Africa. It causes damage by direct feeding on the kernel and comprises more than 80 % of the shield bugs in the orchards. Increased crop losses due to stink bug damage threaten macadamia nut production. Modern pest management practices require an understanding of the biology of pests and ecology. An important question to pose is, how does an organism's thermal plastic traits affect its ecological population dynamics? First, this study aimed to quantify the effects of temperature on biological parameters of B. distincta life stages, such as the development rate, development duration, survival, adult longevity, pre-oviposition period, oviposition period, and life table parameters, to determine its thermal requirements and population growth at constant temperatures ranging from 19 to 29 °C. In addition, the effect of diet (macadamia nut and sweetcorn) on development, survival, and sex ratio was investigated at 25 °C (Chapter 2). Second, to quantify the phenotypic plasticity of B. distincta life stages. Two thermal tolerance indices were explored: rapid hardening (rapid heat hardening: RHH and cold hardening: RCH) and acclimation (critical thermal maximum: CTmax and minimum: CTmin). RHH and RCH were determined by exposing B. distincta life stages to extreme temperatures of 41 and -8 °C, respectively. Acclimation effects on CTmax and CTmin were quantified by exposing B. distincta life stages to 48 h at 20, 25, and 30 °C. Temperature was ramped up and down at a rate of 0.2 min-1 to score survival at high (CTmax) and low (CTmin) critical temperature points (Chapter 3). Thirdly, the development rate was monitored (on the host plant) at temperatures ranging from 18 to 40 °C to acquire the total heat required to complete development (degree-days) and thermal requirements of each life stage of B. distincta. iv Lastly, the physiological traits, degree-days, and thermal requirements were used to predict seasonal generation turn-over, heat and cold thermal stress, thermal safety margin (TSM), and relative fitness in macadamia orchards along an elevational gradient (705 - 1493 m a.s.l.) to determine the effects of climatic zones (Cwa climate zone: Monsoon-influenced humid subtropical climate, Cwb: Subtropical highland climate or Monsoon-influenced temperate oceanic climate, and Bsh: Hot semi-arid steppe climate) (Chapter 4). B. distincta developed at a wide range of temperatures on sweetcorn (18 to 29 °C) and macadamia nut (18 to 35 °C). The survival rate was high (51 to 100 %) between temperatures with a monotonic increase of population growth from 19 to 29 °C. The total number of heat units required to complete development was 783 DD. All life stages of B. distincta displayed thermal plasticity, but instar 2 was the most plastic stage except in response to cold acclimation. Response to extremes varied more at low extreme temperatures compared to high extremes. As expected, the number of generations decreased with increasing elevations from the Cwa (Arbor: 2.4 generations) to the Cwb climate zone (Highfield: 1.1 generations). None of the life stages experienced thermal stress. TSM and relative fitness were highest at the Cwb climate zone of the highest elevation. These findings suggest that B. distincta will potentially cause more damage in response to global warming because of its estimated population growth rate at elevated temperatures. Although relative fitness was highest in the Cwb climate zone, damage could be expected in the Cwa zone due to increased number of generations. This study can also help identify macadamia orchards in climate zones vulnerable to climate-related consequences such as outbreaks. Climatic data combined with the DD model can be used to predict the phenology of B. distincta and timing of chemical applications. The impacts of global warming on crop losses due to insect pests are evident worldwide, and this study has shown that macadamia orchards in certain climatic zones (e.g., Cwa climate zone) could be at risk of increased abundance of B. distincta. Thus, integrated pest management strategies should be of priority to macadamia farmers for effective management of B. distincta. Given that South Africa is the largest producer of macadamia globally and its major pest is thermal plastic, linking the physiological traits of B. distincta life stages to climatic conditions of all macadamia growing regions in South Africa will help understand its distribution limits.Item Open Access An inventory, nutritional analysis and biological evaluation of underutilized indigenous vegetables used to manage non-communicable diseases in Thulamela local municipality, Vhembe District Municipality, South Africa(2022-11-10) Phaswane, Mukhethwa Concila; Masevhe, N. A.; Amoo, S. O.Non-communicable diseases have emerged as a serious public health concern around the world, with a high death rate. The study aim was to document and evaluate the biological activities of underutilized indigenous vegetables used by local people in Thulamela Local Municipality to manage non-communicable diseases. An open structured interview was used to conduct an ethnobotanical survey, and 25 underutilized indigenous vegetables belonging to 13 families were documented. Cucurbitaceae was the dominant family, constituting 21% of the documented species, followed by Urticaceae with 13% of the species. Six of the documented species, which are Citrullus colocynthis, Cleome gynandra, Cucumis africanus, Oxygonum dregeanum, Pouzolzia mixta, and Sonchus oleraceus, were selected and evaluated using standard laboratory procedures for quantifying nutritional, phytochemical constituents, antioxidant, and anti-diabetic activities. The above-mentioned six vegetables contained a considerable amount of important nutrients. Cucumis africanus has the highest levels of ascorbic acid, Ca, Fe, and Mg. In comparison to other vegetables studied, Citrullus colocynthis had the highest levels of total phenolics, total flavonoids, and condensed tannins. The free radical-scavenging activity of all the plant extracts was moderate compared to the positive control (ascorbic acid). On the other hand, dichloromethane and acetone extracts exhibited high antioxidant activity in the beta-carotene-linoleic acid antioxidant system. Most dichloromethane, acetone and distilled water extracts showed low alpha-glucosidase inhibition compared to the positive control (acarbose). However, the dichloromethane extract of Citrullus colocynthis and acetone extract of Cucumis africanus exhibited significantly high alpha-glucosidase inhibitory activity than acarbose. According to the information gathered, people in Thulamela Local Municipality rely on indigenous vegetables for medicine to treat non-communicable diseases. The quantified nutritional and phytochemical contents and the antioxidant and alpha-glucosidase inhibitory activities exhibited by the selected underutilized indigenous vegetables confirm their traditional uses as food and medicine to manage diabetes and other non-communicable diseases. To obtain precise data that can be used to verify these findings, in vivo methods should be used.Item Open Access Genomic mechanisms underpinning phenotypic diversity in the spiral-horned antelopes (Genus: Tragelaphus)(2022-11-10) Rambuda, Thabelo; Moodley, Yoshan; Rakotoarivelo, AndrinajoroThe world is old, full of diversity, and the history of all organisms that once lived on Earth is recorded in the DNA of its descendants. The genomes of living organisms contain ancestral information that, if analyzed, reveals the underlying mechanisms to explain an organism’s evolutionary history. Therefore, it is crucial to study the whole genomes of highly diverse and specialized groups of organisms that could help our understanding of the speciation process. The continent of Africa is home to phenotypically diverse spiral-horned antelopes (genus Tragelaphus) which have gone through a recent adaptive radiation. Previous studies on Tragelaphus have argued that they comprise either nine or ten species based on mtDNA and nuclear DNA respectively/chromosomal number difference. With the same mentioned molecular data, there is discordance in their previously reconstructed species tree, placing species in different clades with different markers. At the mtDNA level, the nyala (T. angasi) is sister to the bushbuck (T. scriptus) making the mtDNA diversity polyphyletic within the bushbuck complex. The two bushbuck species and other phenotypically similar non-sister Tragelaphus lineages lead to the suggestion by scientists that some phenotypes evolved through convergent evolution. In this study, one whole genome of each Tragelaphus lineage was sampled with the aim to analyze the genome-wide relationship of these species by reconstructing their phylogenetic species tree. The study also aims to assess the genome-wide levels of diversity and to assess whether there has been gene flow between species which could have led to phylogenetic discordance among traditional markers. The relationship was analyzed with non-model based PCA and biological model-based IBS and maximum likelihood. All the methods used for structure analysis revealed the same genomic structure and confirmed other studies showing that morphologically similar Tragelaphus species were not most closely related at the genome level. The reconstructed genome-wide species tree was used for the assessment of introgression between species. Most of the observed gene flow was ancestral, the alleles of which are randomly kept in some lineages and passed from generation to generation but lost in others. Therefore, I propose that some phenotypic similarities between unrelated species could be due to high ancestral gene flow between these non-sister lineages. To confirm this would require further investigation using more samples for each species.Item Open Access Ethnoecological investigation of Spirostachys africana Sond. population at Ha-Matsa Village, Limpopo Province, South Africa(2022-11-24) Phalanndwa, Mashudu Victor; Tshisikhawe, M. P.; Magwede, K.Availability of natural resources for the generations to come depends on the current state of harvesting as well as use patterns. Such anthropogenic activities impact on the species survival and functioning of ecosystems. Harvesting of plant species that exudates gum, resins and/or latex like Spirostachys africana Sond. dates as far back as the Middle Stone Age (MSA) period. The demand for ethnobotanical use of plant material particularly tree is continuously increasing particularly in developing countries. This leads to unsustainable and uncontrolled extraction of plant material, involving excessive debarking, felling of the entire trees, root harvesting, and other activities that are currently threatening plant species and indigenous forests. These unfavourable practices mostly lead to most species being threatened. This study investigated ethnobotanical use of S. africana by the Vhavenda at Ha-Matsa village in Vhembe district, Limpopo province, South Africa. This was achieved through interviewing informants using a semi-structure questionnaire. The study further investigated population structure of S. africana and how harvesting is affecting the population of this species. The ethnobotanical data collected showed that various parts of S. africana (mainly branches, bark and stem) are harvested for various uses by Vhavenda of Ha-Matsa village. The study further revealed that the S. africana population at Ha-Matsa village is mainly represented by high number of sub-adults and that this population is failing to recruit seedlings. Lack of seedlings was ascribed to high percentage of crown harvesting and other anthropogenic activities such as manmade fires observed in this study. Furthermore, the basal stem diameter exhibited a bell-shaped distribution curve suggesting that the S. africana population at Ha-Matsa village is unstable.Item Open Access The effects of root severance in savanna trees in Nylsvley Nature Reserve, Limpopo Province, South Africa(2022-11-10) Mulaudzi, Thilivhali Adelaide; Ligavha-Mbelengwa, M. H.; Tshisikhawe, M. P.Root severance has effect on Terminalia sericea and Burkea africana. Burkea africana is a deciduous tree belonging to the family Fabaceae (Caesalpinioideae) while Terminalia sericea is a deciduous tree of the family Combretaceae. Savanna trees respond to root severance in different ways including producing root suckers. Root suckering take place commonly following disturbance events such as fire, and root severance. The root suckers originate from primordia which are formed from meristematic cells in the cork cambium of the roots during secondary growth. The suckering of roots allows individuals spreading from the original establishment site, thereby promoting new sites colonization. Root suckering is affected by light, soil temperature, soil aeration, growth regulators, hormones, and root carbohydrates reserve. The study site was located subjectively in an area dominated by the species under study. Twenty juvenile and adult trees of the two species were selected where one lateral root was cut. The data collected in each selected species are basal stem diameter of trees, tree crown, and tree height; direction of root cut; number of root suckers produced; root sucker diameter and height of the trees. The result shows that root severance by producing root suckers as observed in Burkea africana and Terminalia sericea. More distal root suckers were produced than proximal root suckers. The health of the plant is not affected by either severing root or development of root suckers. The growth or vigour of root suckers depends on the parent root system, where they are initiated, micro environmental conditions such as soil temperature and herbivory. Juvenile plants produced more root suckers compared to adult plants of Burkea africana. Burkea africana responded quickly but Terminalia sericea needs more time to develop root suckers. Therefore, the knowledge of root sucker and root severance of the two species (i.e. Terminalia sericea and Burkea africana) in this study may contribute to the conservation and management recommendation of the population of the species.Item Open Access Genomic diversity and structure among South and East Asian human populations(2022-11-10) Ngoveni, Maria Dunisani; Moodley, Yoshan; Rakotoarivelo, AndrinajoroGenetic variability is a complex concept that is affected by many factors. Studying the genetic variability within the human population provides a better understanding of how populations evolve. The genetic variability within modern humans resulted from different conditions experienced in different routes used by out of Africa migrations to other parts of the world. These events included mating with other human species (Neanderthals and Denisovans) and the development of cultural practices as they arrived in other parts of the world. Asia is more diverse in terms of physical geography, cultures, and languages, which makes it an interesting region to study human population genetic diversity and population structure. From animal studies, colonization of islands is often associated with loss of genetic diversity resulting in isolation. Although humans can easily move around, various aspects could result in isolation between populations. To test the concept of low genetic variability in island populations, I used 1000 genomes project variant calls datasets (autosomal, X-chromosome, Y-chromosome, and mitochondrial data), which include 983 individuals from ten Asian populations. I estimated the genetic diversity from autosomal dataset of South and East Asian populations to compare the genetic affinities between mainland and island populations. Reduced levels of genetic diversity were observed in Japan suggesting a possible genetic bottleneck during the initial colonization of the island. Despite the diverse cultural practices and South Asia being colonized early the populations are not more internally structured nor more genetically diverse compared to East Asia. Most East Asian populations had higher heterozygosity compared to South Asian populations. It is clear from the results that physical geography plays a crucial role in shaping the genetic diversity between populations. Significant levels of gene flow were observed between populations that are at close geographical distance compared to populations at distant proximity.Item Open Access The value of Mopane worms: quantifying ecosystem services in terms of nutrient cycling in semi-arid regions of Limpopo(2022-07-15) Netshanzhe, Mutali Winnie; Swanepoel, L.; Swanepoel, C.; Foord, S.Mopane worms are the late-instar stage caterpillars of the mopane moth, Imbrasia belina/ Gonimbrasia belina, found in southern Africa virtually following their hosts' trees, Colophospermum mopane, Terminalia seriscea, and Sclerocarya birrea, among others. The caterpillars are harvested for consumption and sale, thus crucial for rural livelihoods. Due to their importance to the livelihood of people and the rise in the human population, coupled with poverty, there is growing concern about harvest rates which might pose a risk to their sustainability. It is thus essential that research focused on aspects related to sustainable harvest rates is done alongside research focusing on the general species ecology. This study has two parts; firstly, the study aimed to do a systematic review to determine the current state of knowledge and research on mopane caterpillars in southern Africa. Secondly, the study aimed to assess the contribution of mopane caterpillars’ frass to nutrient cycling by determining the nitrogen mineralization rates of frass compared to that of mopane leaves. We used search engines such as African Journals Online (AJOL), Google Scholar, and Web of Knowledge. The online databases were searched using the following keywords, 'mopane worms', 'mopane caterpillar', 'Imbrasia belina', 'Imbrasia belina caterpillars', and 'Gonimbrasia belina'. All the publications were compiled and evaluated based on title, keywords, and abstract to select only studies focusing directly on mopane caterpillars. Only peer-reviewed publications were included and did not include grey literature, such as reports, presentations, dissertations, or book chapters. A total of 104 publications were found that fit the assessment criteria. The temporal distribution showed that studies on mopane caterpillars began in the 1960s, and there was a steady increase from 1991 onwards. The spatial distribution of publications closely followed the mopane caterpillars distribution in southern Africa. Two main themes emerged from the papers: resource use and ecology. Most papers (79 papers; 76%) focused on resource use, while only 25 papers (24%) focused on the species' ecology. Furthermore, spatially there was a lack of studies in many countries where mopane caterpillars occur, highlighting the spatial bias in studies. The review highlighted that research on mopane caterpillars is biased to resource use, with little attention toward the ecological role the species play in the ecosystem. We conducted an incubation experiment to measure mineralization rates between mopane caterpillars’ frass and mopane leaves. The results showed that frass had high mineralizable N due to the high NH4⁺ and NO3⁻ concentration compared to the whole and fine (ground) leaves. Overall, frass released more inorganic N than leaves; thus, it seems that mopane caterpillars’ frass has high mineralization potential and is essential in aiding nutrient cycling in the ecosystem. From this, we recommend more field and lab studies to establish the mineralization potential of mopane caterpillar frass and the rate at which the frass release nutrients. We also recommend more studies that will focus on consumption of leaves and the release of frass by mopane caterpillars to determine the biomass consumed and consequently returned to the ecosystem by mopane caterpillars.Item Open Access The potential of bats as bioindicators for areas currently transformed by opencast mining within the Vhembe Biosphere Reserve, Limpopo Province, South Africa.(2022-07-15) Cory-Toussaint, Dawn; Taylor, Peter J.; Barnhoorn, Irene E. J.Bats are the second most diverse order of mammals and provide crucial ecosystem services from insect control (including significant crop pest species), to pollination of plants and seed dispersal. Bats are known to be sensitive to alterations in their environment. Globally, bat populations and communities are under pressure due to anthropogenic activities that alter their natural habitats creating unfavourable habitats for some bat species and favourable conditions for others. Anthropogenic activities, impose a multitude of impacts on bats such as artificial lighting throughout nocturnal periods and excessive noise during both diurnal and nocturnal periods. These alterations of habitats affect bat roosting and emergence behaviour, disrupt commuting routes to foraging grounds and alter interspecific competition. Additionally, bats are exposed to and suffer physiological issues relating to contaminants such as heavy metals and trace elements of which their liberation is exacerbated by human activities. African bat conservation is already under considerable pressure from the development occurring throughout the continent. A looming development of significant concern is the proposed African Mining Vision to develop mining and transport networks throughout sub-Saharan Africa. The fate of bat conservation in Africa is dependent on bat taxonomy (with new species regularly described), an understanding of African bat ecology and the responses of bat species to changes in their environment. Research covering these aspects are greatly needed in order to propose environmental mitigation and remediation strategies. Bats have the potential as bioindicators to provide information concerning ecosystem health pre-, during and post- large scale developments such as mining. My study focused on how a bat community in northern Limpopo Province was impacted by the de Beers Venetia opencast diamond mining operation. I investigated which bat species have the potential to be bioindicators based on the impact of habitat degradation (Chapter 2). The impact of artificial light and anthropogenic noise was explored (Chapter 3) and the use of bat fur and blood as biomarkers of bat exposure to heavy metals and trace elements (Chapter 4). Bats have the potential to be good bioindicators as they are easy to monitor in areas like mines that are often a challenge to access and or have high safety risks due to heavy machinery movement and human exposure to possible environmental contaminants. By using passive acoustic recording techniques, the composition and activity of the bat community was determined on the Venetia diamond mine and over the natural areas neighbouring the mine. Six bat detectors were deployed for a full summer and winter season to determine what factors (both anthropogenic and natural) influenced total bat activity as well as species richness and diversity. The effect of habitat type (natural habitats Musina Mopane Bushveld and Limpopo Ridge Bushveld vs altered landscapes of the wastewater dam and opencast pit), season, minimum temperature (Tmin) and moon phase were investigated. Habitat type and season were shown by the best-fit models to be the main factors affecting bat activity, which was lower during winter and consistently lower over the heavily disturbed opencast mining pit. It was evident from the passive acoustic recordings of echolocation calls that the Venetia diamond mine was an important resource for numerous bat species, particularly at the wastewater dam, boasting ~18 out of 22 species/species groups. The wastewater dam provided a sought after resource for foraging and possibly drinking by bats. The infrastructure of the mine was also observed to be used by molossid bats as roosting opportunities. Based on the clear-cut response of three species/species groups to habitat type, Laephotis capensis/Pipistrellus (Vansonia) rueppellii, Afronycteris nana and Pipistrellus rusticus/Neoromicia anchietae were proposed as bioindicators on the Venetia diamond mine. All three species/species groups could be environmental indicators which means that they respond to physical changes in the environment, in this case, changes in preferred habitat. Laephotis. capensis/P. rueppellii generally avoided the mining footprint and were abundant in the natural areas whereas A. nana and P. rusticus/N. anchietae were prolific over the wastewater dam, particularly during winter. The response of A. nana and P. rusticus/N. anchietae may be a reflection of changes in insect species composition over the wastewater dam in relation to potential changes in water quality and as such, have also been suggested as ecological indicators as they may be reflecting the change in another taxon or group (invertebrates). Further research in this regard is required. Bat species were characterised as exploiters and adapters to resources provided by the mine such as new artificial roosting opportunities in infrastructure and resource creation, particularly artificial water sources that would otherwise be scarce for bats in the semi-arid environment. Examples of these exploiter and adapter species were Chaerephon pumilus/Mops condylurus that exploited resources provided by the mine from roosting in buildings to using the wastewater dam, and P. hesperidus as an adapter that used the wastewater dam as an important resource particularly during winter and was only recorded in natural areas during summer but is not known to roost in the infrastructure of the mine. Even though the mining activities provided resources, bats were exposed to continuous anthropogenic noise and artificial light during their night-time foraging period. To investigate the impacts of anthropogenic noise and artificial lighting, a transect was installed on the Venetia diamond mine using six SM4BAT acoustic recorders (bat detectors) (Wildlife acoustics, Inc.) to passively record bat species and their associated activity. The transect began in a brightly lit area near some workshops and a conveyor belt system and extended past the well-lit and noisy processing plant, into an open-air laydown storage area and terminated in natural vegetation. Surprisingly, according to mixed-effects models, in general, anthropogenic noise did not have a significant impact on bat activity or species richness. Artificial light only negatively impacted foraging activity and there was little evidence of bats foraging under the floodlights near the workshop and processing plant. Artificial light may possibly impact total bat activity and searching/commuting behaviour. In support of the data concerning the lowest bat activity and species richness over the habitat devoid pit of the mine, the percentage of natural vegetation cover was the most important factor influencing all bat activity and species richness. With significant bat activity recorded over the mine wastewater dam, there is potential for bats to be exposed to high concentrations of contaminants, particularly heavy metals and trace elements that would otherwise be naturally occurring at lower concentrations in the environment. Therefore, I investigated the potential bioaccumulation of elements in molossid bats from the mining footprint and in a control area adjacent to the mine. There is great interest in using bats as bioindicators of environmental contaminants and with a focus on non-lethal and less invasive methodologies, the fur and blood of several Tadarida aegyptiaca and C. pumilus/M. condylurus was tested for 23 elements. Fur is a good indicator of exposure to elements over an extended period and blood provides insight into more recent exposure. Fifteen of the 22 elements (barium excluded as it was predominantly below detection limits), were higher in the fur that in the blood samples. Concentrations of boron (B), potassium (K), rubidium (Rb) and cadmium (Cd) in fur and zinc (Zn), and mercury (Hg) in blood were significantly higher in samples from the opencast diamond mine compared with the control site. Manganese (Mn) was higher in the blood of bats from the control site than from the mine. Although weak, the only significant correlations between fur and blood element concentrations were found for Hg and strontium (Sb). Comparative data with other bat species is scant in the literature and there are currently no toxicological thresholds for elements in bats, thus the low concentrations of most elements, except aluminium (Al), iron (Fe) and Zn, may reflect background values. These data are the first presented to compare blood and fur elemental concentrations of South African bats the implications of which are currently unknown. 3 These data presented in my thesis has great potential to add to the environmental monitoring of the Venetia diamond mine by providing insight into trends in the bat population (including species richness) that utilise the mine associated (drinking and foraging areas over the waste water dams, and roosting opportunities in mine infrastructure). These data can be used as a baseline to monitor the current and future environmental impacts of the mine as production continues and, can be used to monitor and assist rehabilitation efforts soon to be underway.Item Open Access Evolutionary Genomics of the Trans-Atlantic Slave Trade(2022-07-15) Ndou, Maanda; Rakotoarivelo, Andrinajoro; Moodley, YoshanThe Trans-Atlantic Slave Trade is a remarkable large-scale migration in the human history. On several occasions between the 16th and 19th century, millions of African men, women, and children were purchased from African traders and some abducted for slavery by the Europeans, for forced labour in the European colonies established in the American continent. The barbarous nature of the slavery left significant genetic modifications in the ancestry of modern-day descendants of former slaves (African Americans in United States and in Barbados). This research uses differently inherited high coverage Whole Genome Sequences (WGS) from autosomal, X, Y, and low coverage mitochondrial chromosomes collectively to present a detailed genetic point of view of the African Americans, their genetic relations to Africans and their interactions with America’s other residents: Europeans and Native Americans. The results show that African slaves were abducted from West Africa (dominantly from Nigerian populations). Gene flow patterns were observed among former African slaves, their European slave masters, and Native American populations, resulting in genetic diversity among modern-day African Americans that is greater than any other population currently inhabiting the Americas and even higher than their source populations in Africa. The gene flow pattern was unidirectional from Europeans to African Americans and Native Americans, but bidirectional between the African Americans and Native Americans.Item Open Access Seasonal use and mortalities of mammals along the Phalaborwa – Hoedspruit railway line in Balule Nature Reserve, South Africa.(2022-07-15) Thela, Siboniso Khulekane; Swanepoel, L. H.; Bhardway, M.; Collison-Jonker, W. J.Railways are essential transportation corridors that facilitate the movement of goods and people with important environmental and economic benefits. Despite these benefits, railways and trains can negatively affect wildlife through mortalities, barrier effects, disturbances, and habitat loss. There is growing evidence that human activity negatively affects the spatial distribution of wildlife in relation to the distance from the infrastructure and wildlife also adjust their spatiotemporal activity to avoid or minimize encounters of human activity. Moreover, wildlife mortalities due to collision with trains are a major conservation concern which can jeopardize the persistence of wildlife populations as wildlife-train collisions are non-specific with regard the species, age and sex of the animal affected. In this study, I assessed the activity patterns of six medium-large sized mammals (≥ 10 kg) and monitored the mortalities of wildlife from four different taxonomic groups on the landscape bisected by the railway line in Balule Nature Reserve. Impala and giraffe occurrences on the railway line is mostly diurnal. Meanwhile, lion occurrence on the railway line is mostly nocturnal. Four of my focal species moderately overlapped with train activity, with no seasonal differences in their degree of activity overlap. African buffalo and elephant activity decreased with increasing distance from the railway line. Giraffe, impala, and lions are less active around the railway line in the wet season than the dry season. Spotted hyaena are more active around the railway in both open grassland and woodland compared to mixed shrubland habitat intersecting the railway. I recorded a total of 99 rail-kills from a total of 450 km surveyed over a 90-day period. Of these rail-kills, mammals were recorded more often (29.29%), followed by birds (26.26%), reptiles (26.26%) and amphibians (18.18%). There was no significant difference in the frequency of mortalities on the railway line between seasons (U = 286.5, n = 49, p = 0.421). The rail mortalities of diurnal did not differ significantly from nocturnal species (x² = 0.55, df = 1, p = 0.458). However, there were significantly more mortalities of diurnal species than nocturnal species on the railway line during the dry season (p < 0.05). Most encountered deaths on the railway line occurred in a mixed shrubland section but there was no significant association in the frequency of rail mortalities and rail-side habitat type (H = 0.84, df = 2, p = 0.657).Item Open Access Frass from black soldier flies as a valuable fertilizer and biopesticide for crops(2022-07-15) Kubayi, Consol; Foord, S. H.; Madala, N. E.; Swanepoel, C. M.Recently, insect farming has gained recognition globally. This is particularly true for the black soldier fly, Hermetia illucens. However, the byproduct of insect feeding, a combination of food residue and frass left by the insects after harvesting, has not been given much attention and even fewer studies focus on the use of frass as a bio-fertilizer. In sub-Saharan Africa, human populations are expected to double by 2050, expensive fertilizers and increased food prices will exacerbate conditions further. This study is divided into three data chapters. Firstly, we conducted a systematic review of published literature on BSF (black soldier fly) larvae frass. In this review we collected literature from across the world, and we compared the research done in Africa with that of the rest of the world. The results show that more studies have been done in developed countries (82 %) as compared to developing countries (18 %). Topics explored around BSF frass included waste disposal, organic fertilizer, bioconversion, chemical composition, and economics. The results from all these studies show that frass can be used as a complementary organic fertilizer or independently. However, none of the papers have explored all the benefits of frass and the impact of different waste streams on frass quality. A better understanding of pH and electrical conductivity (EC) impact on frass as fertilizer are required. Secondly, the data chapter presents the results from a greenhouse pot trial where we assessed the effectiveness of frass as a potential biofertilizer to improve plant growth. Frass was compared to commercial fertilizer and a control in a greenhouse at the University of Venda. Amaranthus hybridus was used in the pot trial, and growth parameters that were measured included number of leaves, plant height, dry biomass, and chlorophyll. The results indicated that dry biomass is highest in the NPK (Nitrogen, Phosphorus, and Potassium) treatment, with the control treatment being the lowest. Frass application at the lowest level did not significantly differ from the control, however, the biomass increased with in response to increased BSFL (black soldier fly larvae) frass addition and commercial fertilizer. The addition of 20g of frass improved all the parameters, and they performed similarly with commercial fertilizers. Frass maturity was performed through phytotoxicity test, and further evaluated the efficiency of frass tea as a biopesticide for crop pests through foliar spray technique. The results further revealed that frass used in the study was not matured enough iii as the relative root growth rate was below 50 %, hence it was phytotoxic. Less leaf damage was observed in brewed frass tea compared to boiled frass tea as it was utilized as a foliar spray. Lastly, ultra-high-performance liquid chromatography- quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) and some chemometric software including XC-MS and R-Software were utilized to characterize different metabolites found in Amaranthus hybridus. A total of 30 metabolites have been identified including derivatives of coumaric acid, caffeic acid, ferulic acid, and flavonoids. These metabolites serve different functions in plants including plant defence against pests and cardiovascular diseases in humans. Different frass treatment levels affected the distribution of metabolites. In conclusion, frass remains a promising option to substitute inorganic fertilizers, thus reducing global warming challenges and alleviating poverty in developing countries.Item Open Access An investigation of the genetic integrity of Oreochromis species and incurring in Nandoni and Albasini Dams using the control region of mitochondrial DNA(2020-02) Mboweni, Vusi Besil; Moodley, Y.; Barnhoorn, I. E. J.The genus Oreochromis represents a radiation of mouth-breeding Tilapiine fish inhabiting lakes and rivers throughout Africa. Due to incomplete reproductive isolation, most of the 31 species within this radiation can interbreed giving rise to fertile F1 hybrids. Oreochromis mossambicus is endemic to southern Africa but is now coming under threat throughout much of the sub-region because of the introduction of invasive Oreochromis species, which typically inhibit other parts of Africa. Due to their exceptional growth rates, invasive species were brought to South Africa for the aquaculture industry, and it is feared that they may have hybridized with or displaced O. mossambicus. This study aims to determine, using genetics, the extent of invasion of non-native Oreochromis species into Nandoni and Albasini dams of the upper Levubu in Limpopo South Africa. It is suspected that O. niloticus entered the River after the creation of Albasini Dam, which is upstream of Nandoni Dam. Therefore, it is predicted that typically O. niloticus mtDNA haplotypes will be observable in Nandoni, but that their frequency should be much lower upstream in Albasini Dam. I collected 141 samples from both dams, amplified and sequenced the control region of mitochondrial DNA. I then reconstructed networks and phylogenies with our samples combined with the downloaded samples from which I was able to determine the magnitude of Oreochromis invasion into the upper Levubu. Surprisingly, not one of the sequenced samples possessed a haplotype that clustered with O. mossambicus reference samples. However, I was able to identify two invasive species within the upper Levubu: O. andersonii in both Albasini and Nandoni dams and O. niloticus in Nandoni Dam. Oreochromis andersonii has high genetic diversity and with evidence of demographic expansion based on results from its mismatch distribution and Bayesian skyline plot. These results provide insights into the events that led to the invasion of foreign Oreochromis species to the Levubu system. A genetic signal for a demographic xi expansion might have been caused by O. andersonii haplotypes being in the system before the “big flood” in the year 2000, with a re-introduction into Nandoni after the flood from a different source. This could explain why some haplotypes of O. andersonii are present in both dams and some are only present in Nandoni Dam. Oreochromis niloticus on the other hand, has low genetic diversity in Nandoni Dam compared to downloaded samples, and was probably introduced only once, and may have undergone a demographic bottleneck. From these results, it is clear that O. mossambicus has been all but replaced by non-native Oreochromis in the upper Levubu. Hybridization or total replacement of O. mossambicus may have also occurred in another river system across its native range. O. mossambicus is better adapted to poorer eutrophic conditions and, most importantly it is well adapted to high salinity. Therefore, a strategy conserving genetically diverse O. mossambicus population in the lower reach of the river system, where there is higher salinity, like the lower Changane river, could be most appropriate for this species. The estuarine swamps could then become a refuge for O. mossambicus within its native range.Item Open Access An inventory of woody and herbaceous invasive alien plants in Thohoyandou Botanical Garden, Limpopo Province, South Africa(2021-10-07) Neluonde, Mboneni; Ligavha-Mbelengwa, M. H.; Tshisikhawe, M. P.Species migration out of their local range into new zones by people has brought about the rise of biological invasions. Exotic or non-native species need to conquer various boundaries to establish, naturalize, produce localized self-supporting populations, and in the end spread naturally before they are considered as invasive. These invasive alien species are currently perceived as key drivers of human’s instigated global change as they have negative impacts on biodiversity, ecosystem services and human prosperity which makes the investigations on invasive species imperative to direct approach plan and management important. This study was motivated by the need to control invasive alien plants in protected areas and this inventory of invasive alien plants (IAP) marks the first step in creating baseline data for managing invasive alien plants in the garden. Protected areas are threatened by the impacts of invasive alien plants that invade them and Thohoyandou Botanical Garden is no exception. Invasive alien plants are the second greatest threat to biodiversity worldwide and estimates suggest that invasive alien species cost the country over R 6.5 billion per year. The study aimed to document the woody and herbaceous invasive alien plant species in Thohoyandou Botanical Garden in the Vhembe District. Three belts of 100 m x 500 m were constructed and within them quadrats of 10 m x 10 m were randomly constructed. All the invasive alien plant species were identified and grouped as per their growth forms. Their impacts on the adjacent native species were investigated and their health status identified using a sliding scale of 1 – 5, where 5 is healthy and 1 is unhealthy. All the data were stored in Microsoft Excel and later analyzed using One-way analysis of variance(ANOVA) was also used to compare mean frequency count and mean height between invasive and native species. Data was analysed through the Microsoft Excel programme. This study has shown that invasive species have the potential to reduce native species at a rate of 2.92 species per every 40 invasive species, on average. Thus, for every 40 invasive species that are found in any chosen area within Thohoyandou Botanical Garden, an average of 3 native species will be lost as a result. These results have a very strong implication in that they can guide management and control strategies aimed at ensuring that the impact of invasive species on the growth and survival of native is kept to minimal levels.