Showing papers in "Transactions of The Royal Society of South Africa in 2016"
TL;DR: It is concluded that those responsible for the conservation of these ecosystems will face many challenges in the 21st century, including finding ways for effectively managing invasive alien plants and fires, as foreseen by the Wicht Committee.
Abstract: In 1945, the Royal Society of South Africa published a wide-ranging report, prepared by a committee led by Dr C.L. Wicht, dealing with the preservation of the globally unique and highly diverse vegetation of the south-western Cape. The publication of the Wicht Committee’s report signalled the initiation of a research programme aimed at understanding, and ultimately protecting, the unique and diverse ecosystems of the Cape Floristic Region. This programme has continued for over 70 years, and it constitutes the longest history of concerted scientific endeavour aimed at the conservation of an entire region and its constituent biota. This monograph has been prepared to mark the 70th anniversary of the Wicht Committee report. It provides a detailed overview of the circumstances that led up to the Wicht Committee’s report, and the historical context within which it was written. It traces the development of new and substantial scientific understanding over the past 70 years, particularly with regard to catchment...
58 citations
TL;DR: This comprehensive book deals with phytophagous (plant-feeding) insects that damage field crops, deciduous, tropical and other fruits, vegetables, plantation trees, ornamental plants, turf grasses as well as natural pastures.
Abstract: This comprehensive book deals with phytophagous (plant-feeding) insects that damage field crops, deciduous, tropical and other fruits, vegetables, plantation trees, ornamental plants, turf grasses as well as natural pastures. A total of 75 cultivated plants, or groups of plants, are covered. There are 416 full accounts of the most important pests, with an additional 277 insects of lesser importance being listed. Each insect pest account gives its scientific and common names (in English and Afrikaans, and, where available, in Portuguese), its origin and distribution, identification (eggs, immature stages and adults), its host plants with an indication of the plant parts that the pest feeds on or damages, life history, its natural enemies and management, and with key references to literature for further reading. There are 860 full-colour, high quality photographs to aid in the identification of adults, eggs, immature stages and damage symptoms. An extensive glossary of entomological terms is also provided to facilitate the use of the book. The index includes scientific and common names of insect pests and of host plants.
54 citations
TL;DR: Resilience acknowledges that systems are dynamic - 'nothing is constant except change'; that unexpected and nonlinear change can occur when thresholds are crossed; that complex interactions exist between social, political and ecological elements of the system with multiple feedbacks across scales.
Abstract: Stimulated by the global financial crisis, threats to world security and the inevitability of climate change, resilience has shown a marked increase in academic literature since the mid-1980s. Resilience is not quite the same as sustainability. It acknowledges that systems are dynamic - 'nothing is constant except change'; that unexpected and nonlinear change can occur when thresholds are crossed; that complex interactions exist between social, political and ecological elements of the system with multiple feedbacks across scales; and that stressors and drivers of the system can act together, often synergistically, to create surprise.
51 citations
TL;DR: The present study enhances knowledge of distribution patterns for these larger mammal species in a large part of the southern African sub-region during the early historical period and provides a first attempt to describe the sub-regional scale, historical, distribution patterns within the context of the broad biogeographical characteristics of the area in question.
Abstract: Distribution data form the basis of the study of zoo-geography, which has applications in, inter alia, ecology and conservation. Written records were used to estimate the distribution patterns of some of the medium- to large-sized terrestrial mammals in central, southern and western South Africa, and neighbouring Lesotho, during the early historical period (late 1400 s to the 1920s). The sources of these records comprise mainly published or unpublished letters, journals, diaries or books written by literate pioneers – notably various missionaries, explorers, travellers, naturalists, military personnel, big game hunters and agro-pastoralists. The classification (according to record type) of the written records in key publications was standardised, and records overlooked by them are taken into account. Interpretation of the spatial patterns provided by the written records was aided by reference to supporting information, in the form of qualifying palaeontological, zoo-archaeological and museum records. Writ...
51 citations
TL;DR: In this paper, the authors explore the link between exports, scientific use, and invasive populations and chytrid outbreaks and show a lag between exports of Xenopus laevis and a rise in invasive populations of around 15 years.
Abstract: Trade in live animals has been associated with populations of invasive species as well as the spread of disease. The African clawed frog, Xenopus laevis, was exported from its native region of southern Africa for use in pregnancy testing, and later for laboratory use as the model amphibian. We use historical export figures and publication records to detail the size and extent of the global trade. In addition, we explore the link between exports, scientific use, and invasive populations and chytrid outbreaks. Exports reached 400 000 animals in the first 30 years from 1940, but only 86 000 were sent outside Africa. Exports out of Africa peaked in the 1950s, while scientific publications using Xenopus laevis grew in the 1970s, coinciding with a rise in invasive populations and chytrid outbreaks. We show a lag between exports of Xenopus laevis and a rise in invasive populations of around 15 years. Our data demonstrate the global reach of the exports of Xenopus laevis from South Africa, and a later, much wider...
39 citations
TL;DR: The landfall of Tropical Storm Dando resulted in a severe flood event in the Lowveld region of the Limpopo Province in South Africa from 17 to 19 January 2012, with over 500mm of rainfall recorded over a 24-hour period as discussed by the authors.
Abstract: The landfall of Tropical Storm Dando resulted in a severe flood event in the Lowveld region of the Limpopo Province in South Africa from 17 to 19 January 2012, with over 500 mm of rainfall recorded over a 24-hour period. The Mopani District Municipality declared a local state of disaster following these floods. Interviews conducted with 24 lodges and conservation establishments indicate a total direct cost of R58.92 million, ‘costs’ of loss of business of R4.230 million, and an increase in long-term expenses, including insurance, adaptation and mitigation, of R458 600. Due to the low response rate, the economic damage to the tourism sector exceeds that of the 42 farms and 11 local businesses interviewed. Damage ranged from the loss of household contents to the complete destruction of all buildings on the property. The capacity for tourism establishments to recover from the floods depended primarily on the type and value of their insurance. Additional strain was placed on tourism establishments through the...
35 citations
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TL;DR: In this paper, the authors define peaks and consider various parameters relating to peaks and find the generating functions that count these parameters and then find the mean for each statistic, and compute the asymptotics of these means as the length of the semi-perimeter of the bargraph tends to infinity.
Abstract: Bargraphs are specific polyominoes or lattice paths in . They start at the origin and end on the -axis. The allowed steps are the up step , the down step and the horizontal step . There are a few restrictions: the first step has to be an up step and the horizontal steps must all lie above the -axis. An up step cannot follow a down step and vice versa. In this paper, we define peaks and consider various parameters relating to peaks. We find the generating functions that count these parameters and then find the mean for each statistic. We also compute the asymptotics of these means as the length of the semi-perimeter of the bargraph tends to infinity, where the semi-perimeter is the sum of all the up and horizontal steps.
27 citations
TL;DR: In this paper, the authors investigated wetland utilisation patterns as well as the status of benefits derived by surrounding communities in Runde, Tongogara and Vungu rural districts of Zimbabwe.
Abstract: Wetlands are among the most threatened natural ecosystems in developing countries. Loss of wetlands is attributed to, among other factors, inadequacy in information on the resource's value to rural communities. This paper investigates wetland utilisation patterns as well as the status of benefits derived by surrounding communities in Runde, Tongogara and Vungu rural districts of Zimbabwe. Two sets of questionnaires were used to gather data from 123 household heads and 60 teenagers. Snowball sampling was used to select 14 elderly people for semi-structured interviews. Land cover changes were established through analysis of the 2013 RapidEye imagery and aerial photographs (1985 and 1996). The results of land cover change analysis indicate an increase in spatial extent of cultivated area, water and bare land, and a decrease in the area covered by sparse and dense vegetation. Meanwhile, the majority of households revealed that there is no change in wetland utilisation patterns as cultivation continues to domi...
22 citations
TL;DR: Three possible scenarios that may apply to a new hominin species of unknown geological age are outlined, exploring the implications of geological age for understanding its role in human evolution.
Abstract: We have recently described a new hominin species, Homo naledi, of unknown geological age. This provides a unique opportunity to present evolutionary hypotheses that will be tested when a date becomes available. We outline three possible scenarios that may apply to this species, exploring the implications of geological age for understanding its role in human evolution. The phylogenetic placement of H. naledi does not depend upon its geological age, but other aspects of the hominin record do.
14 citations
TL;DR: The results proved the hepatoprotective potential of ALEG versus CCl4-induced oxidative stress and extensive liver damage characterised by vacuolar as well as severe necrosis with cytoplasmic degeneration in the hepatotoxic and pre-treatment groups, however, such liver damages were not observed in the ALEG-treated groups.
Abstract: Gazania krebsiana (Less.), a member of Asteraceae family, is locally used in the treatment of various ailments mostly among the Basotho tribe of eastern Free State Province, South Africa. The study examines the antioxidant and hepatoprotective potentials of the plant extract on feed and water intake, biochemical parameters such as alanine transaminase (ALT), aspartate transaminase (AST), catalase (CAT), glutathione peroxidase (GP), lipid peroxidation and organ histology. Various concentrations (1.56–25 µg/ml) of aqueous leaf extract of G. krebsiana (ALEG) were tested in in vitro assays. Hepatic injury was induced in the rats by administering 1 ml/kg body weight (BW) CCl4 in olive oil except in the control group. The effects of treatment with 125, 250 and 500 mg/kg ALEG was investigated in vivo during the 15-day study. Water extract exhibited the best activity against four of the six tested free radicals with an IC50 of 3.32 ± 0.06, 5.00 ± 0.06, 0.60 ± 0.04 and 0.70 ± 0.10 µg/ml in 1,1-diphenyl-2-picryl hy...
11 citations
TL;DR: Analysis of rumen-contents to quantify the use of C. mopane and other plants browsed by the greater kudu in the dry season shows that C.mopane contributed the most (47%) to the diet of the greaterKudu during the drySeason.
Abstract: Colophospermum mopane, commonly known as mopane, provides essential browse to the greater kudu (Tragelaphus strepsiceros), especially during the dry season. This study uses analysis of rumen-contents to quantify the use of C. mopane and other plants browsed by the greater kudu in the dry season. The study was conducted at the Sandown Game Farm, Musina Local Municipality, Limpopo Province of South Africa. Rumen samples were collected from three male and two female greater kudu culled in June 2014 and statistically analysed using t-Test: Paired Two Sample for Means and Pearson Correlation Coefficient analysis. Findings show that C. mopane contributed the most (47%) to the diet of the greater kudu during the dry season. Other important browse plants were Dichrostachys cineria (30%), Commiphora edulis (12%), Grewia bicolor (6%) and Combretum apiculatum (5%), with the contribution of T. prunioides and G. flava to the diet being insignificant. The plant parts mostly browsed were leaves, which contributed 75% to...
TL;DR: It is suggested that ethanol leaf extract of L. cyanescens possessed hypoglycaemic effect, and that one of the mechanisms by which this extract elicited its hyp glucosecaemic property may be through the inhibition of diabetes-related enzymes (pancreatic α-amylase and intestinal α-glucosidase) activities.
Abstract: This study evaluated the in vitro inhibitory effects of different extracts of L. cyanescens leaf on the activities of diabetes-related enzymes (α-amylase and α-glucosidase) and the effect of its ethanol extract on postprandial hyperglycaemia in starch-loaded rats. Results of this study revealed ethanol extract as the most potent inhibitor of α-amylase (IC50: 3.69 mg/ml) and α-glucosidase (IC50: 0.13 mg/ml). Lineweaver–Burk plots of the enzyme kinetics showed that the mode of inhibition of α-amylase by the ethanol extract of L. cyanescens is competitive, while it inhibited α-glucosidase non-competitively. Administration of ethanol extract of L. cyanescens leaf to starch-loaded Wistar rats significantly (p < 0.05) reduced the postprandial blood glucose level of the rats within two hours compared to the control animals. This study suggests that ethanol leaf extract of L. cyanescens possessed hypoglycaemic effect, and that one of the mechanisms by which this extract elicited its hypoglycaemic property may be ...
TL;DR: In this paper, the utility of remote sensing technologies for extracting critical information on dam water levels for uMzingwane dam, in the south western part of Zimbabwe, for the years 2007, 2009, 2011 and 2013 was assessed.
Abstract: Accurate, reliable and continuous monitoring of water reservoirs is critical for sustainable water harvesting as well as planning by different water resources management authorities, especially in semi-arid environments. This study thus assessed the utility of remote sensing technologies for extracting critical information on dam water levels for uMzingwane dam, in the south western part of Zimbabwe, for the years 2007, 2009, 2011 and 2013. The Normalised Difference Wetness Index (NDWI), computed from multi-Landsat ETM+ and Landsat 8 images, was applied to extract the dam water levels. Our results indicate that the dam water levels varied significantly (α = 0.05) from 2007 to 2013. It was further observed that dam water levels increased with the increase in rainfall patterns, within uMzingwane catchment between the year 2007 and 2013. The findings of this research therefore demonstrate the importance of remote sensing techniques in assessing water resources in data scarce areas.
TL;DR: Autonomy and justice were the two main ethical principles identified and their conflicting issues with regards to renal replacement therapy (RRT) and they could be considered to cause more harm to patients than benefits and limited patient engagement resulting in non-adherence to management among CKD patients.
Abstract: The objective of this review was to highlight the ethical, legal and cultural implications in the management of chronic kidney disease (CKD) patients.Articles were identified from online databases, namely Medline, PubMed, google scholar and grey literature. A comprehensive search was done to identify articles which highlight the cultural, ethical and legal implications regarding the management of CKD patients and 42 of them were identified.Autonomy and justice were the two main ethical principles identified and their conflicting issues with regards to renal replacement therapy (RRT). Supply and demand with kidney donation and transplantation has led to numerous ethical and moral issues among CKD patients. Although there have been developments in the legal and ethical frameworks to follow, RRT remains a controversial issue.The conflict between justice and autonomy is critical to analyse when looking at the existence of RRT for CKD patients around the world. Conflicting ethical principles could be considere...
TL;DR: The Birders of Africa as mentioned in this paper is an account of the Greater Honey guide and its long association with man in Africa, which sets the scene for a new historical approach to how ornithology with its northern hemisphere traditions has interacted with information provided by African people.
Abstract: Opening with an account of the Greater Honey guide and its long association with man in Africa, this book sets the scene for a new historical approach to how ornithology with its northern hemisphere traditions has interacted with information provided by African people. The title Birders of Africa suggests a wider readership than the academic target audience. 'Birder' in current popular usage implies recreational birders, who often focus on cataloguing and collecting experiences and photographs, rather than physical specimens in the tradition of many characters in this book. Readers who might categorise themselves as 'birders' would likely be discouraged by an introduction with quotations from theories relating to the asymmetries of knowledge, though they could find much of interest elsewhere in the text. The introduction needs to be read with close attention, since Nancy Jacobs sets out clearly her choice of terminology and the aims of her approach to the subject.
TL;DR: Hydro-ethanol extract of D. burgessiae possessed antioxidant as well as antidiabetic potential, and one of its mechanisms of antidi diabetic action is the inhibition of diabetes-related enzymes.
Abstract: This study evaluated the in vitro antioxidant and antidiabetic potential of different extracts of Dombeya burgessiae leaf. Different concentrations (3.13–100 µg/ml) of aqueous, ethanol and hydro-ethanol extracts of D. burgessiae were subjected to standard in vitro antioxidant tests, namely 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl and superoxide radical scavenging abilities as well as iron chelating potential. The antidiabetic study was done by assessing the inhibitory effects of these extracts on the activities of diabetes-related enzymes (α-amylase, α-glucosidase, maltase and sucrase). Ethanol extract of D. burgessiae exhibited the best DPPH radical (EC50: 68.45 µg/ml) scavenging ability while hydro-ethanol extract displayed the most potent hydroxyl (EC50: 30.71 µg/ml) and superoxide (EC50: 27.09 µg/ml) radical scavenging, as well as iron chelating (EC50: 38.09 µg/ml) ability. Hydro-ethanol extract also exhibited the best inhibition of α-amylase (IC50: 43.99), α-glucosidase (IC50: 10.94 µg/ml) and ...
TL;DR: In order to reduce the energy losses resulting from the thickness of large burning glasses, the French naturalist the Comte de Buffon proposed that such lenses should consist of a relatively small central lens surrounded by a series of stepped annular glass rings, all ground to direct light to the same focal point as mentioned in this paper.
Abstract: In order to reduce the energy losses resulting from the thickness of large burning glasses, the French naturalist the Comte de Buffon proposed that such lenses should consist of a relatively small central lens surrounded by a series of stepped annular glass rings, all ground to direct light to the same focal point. In order to simplify the problems associated with manufacturing such rings, the Scottish physicist Sir David Brewster suggested in 1822 that it would be simpler if each annular ring consisted of a number of separate close-fitting segments. Convinced of the importance for scientific research in Britain of the availability of a burning glass larger than could be afforded by any single institution, he proposed the construction of a ‘National Burning Apparatus,’ “to the construction of which all the scientific institutions in the kingdom might contribute” – a remarkably prescient vision of the need for and value of national research facilities. He also outlined some of the important research that m...
TL;DR: In this article, the authors examined the application of remotely sensed derived landscape metrics to understand the changes and dynamics in the form and morphology of forested areas in rural parts of Zimbabwe from 2002 to 2011.
Abstract: This study examines the application of remotely sensed derived landscape metrics to understand the changes and dynamics in the form and morphology of forested areas in rural parts of Zimbabwe from 2002 to 2011. Specifically, the study determines the spatial and temporal changes in forest areas due to human activities, such as crop production, using landscape metrics derived from classified Landsat remote sensing images. The results from this study have shown that landscape metrics derived from the 30-m Landsat dataset have a great potential for understanding the patterns of change in forested areas in the developing world. For instance, in the year 2002, the majority of the land was occupied by forests, whereas in 2011, it was shown that non-forested areas became more dominant and scattered, and forested areas showed a decrease in spatial extent. Moreover, statistical results have shown that in 2002, the number of forest patches was higher and significantly different when compared to non-forested patches....
TL;DR: The story of a boy who grew up to become a naturalist, fish behaviourist and science educator is described in this article, with a life and career almost seamlessly intertwined with the discovery of the coelacanth.
Abstract: Most scientists are passionate about their research subjects,and almost all have fascinating stories to tell. However, a minority seems to have a natural inclination to share their scientific experiences and findings beyond scholarly communities, and fewer still are gifted public communicators (although much can apparently be achieved through practice). For Mike Bruton, science communication was a natural extension of scientific research. Even as a young field researcher he made an effort to communicate his science and findings to local communities. In later years, much of his professional focus was driven by a strong conviction that "scientists need to communicate with the public in a less formal and more entertaining way" (p. 271). For the author, decades of practising this principle has honed an exceptional skill to share the wonders of science in a most captivating and lucid way. Bruton's memoir is the story of a boy who grew up to become a naturalist, fish behaviourist and science educator; a life and career almost seamlessly (and inevitably so) intertwined with the discovery of the coelacanth.
TL;DR: Microvascular patterns found closely resembled those described in mammals, especially around the intraduodenal portion of the choledocho-pancreatic duct at the level of the intestinal lamina propria.
Abstract: The microvascular anatomy of the extrahepatic bile ducts, extrapancreatic ducts and choledocho-pancreatic duct of the adult African Clawed Toad, Xenopus laevis (Daudin) was studied by scanning electron microscopy (SEM) of vascular corrosion casts (VCCs) and light microscopy of paraffin-embedded tissue sections. Branches of the hepatic artery supplied the vascular bed of the extrahepatic bile ducts with arteries running along the serosal surface of ducts. Oblique side branches gradually invaded the bile duct walls. Terminal arterioles capillarised first in the muscular layer and finally formed a dense subepithelial capillary network. Postcapillary venules from the subepithelial capillary bed merged with those from the external layers of the duct walls and formed subserosal venous plexuses. Duct veins drained into nearby veins. The choledocho-pancreatic duct opened at the crest of a duodenal fold which at this site formed a papilla. A ring-like venule was found at the apex of this papilla. A ring-like venou...
TL;DR: In this paper, the authors present a series of commonly asked questions in small bite-sized segments to assist the reader in getting to grips with the fundamentals and uncertainties of climate change in the southern African context.
Abstract: Climate change - what is it, what will it do to our planet and what should we be doing about it? Are cows the culprits...? Coming 'hot' off the hottest two years (2014 and 2015) in recorded history (since 1880), this timely and fascinating book expertly unpacks a series of commonly asked questions in small bite-sized segments to assist the reader in getting to grips with the fundamentals and uncertainties of climate change in the southern African context. The authors start by making it abundantly clear that people are responsible for current climate change and that people should be doing something about it. The book is divided into four sections that address: (1) the processes that underlie climate change; (2) the consequences for the South African environment; (3) the consequences for local society; and (4) the methods of adapting to and mitigating climate change. Within each section, the authors pose and answer a number of relevant questions in what they call 'briefings'. The questions/briefings refer back to one another and lead from one to the next, but can equally easily be read on their own. The small digestible chunks make the book very easy to pick up,put down and pick up again. It's like a question and answer session with an expert panel.
Journal Article•
TL;DR: Maggie Campbell Pedersen's Ivory as mentioned in this paper is a remarkable book full of general and specific knowledge about the numerous ivories that have been highly valued by humans over many centuries and contains an abundance of interesting and little known details about all aspects of conserving ivory-bearing species and the trade in ivory, on working and testing ivory, and about the history of its attraction for items of art and utility around the world.
Abstract: With its very simple title, Maggie Campbell Pedersen's Ivory is a remarkable book. It is brim-full of general and specific knowledge about the numerous ivories that have been highly valued by humans over many centuries. It contains an abundance of interesting and little known details about all aspects of conserving ivory-bearing species and the trade in ivory, on working and testing ivory, and about the history of its attraction for items of art and utility around the world. Appendices explain how to identify different ivories and a dichotomous key of the diverse ivories and their imitations is provided. A long and helpful glossary is included as is an extensive bibliography.
TL;DR: The current Ebola epidemic in West Africa is the largest and most complex outbreak of the disease to date, and there are fears that it could develop into a major pandemic, but certain measures can be taken to combat the virus and prevent it from spreading in South Africa.
Abstract: The current Ebola epidemic in West Africa is the largest and most complex outbreak of the disease to date. First discovered in 1976 following an outbreak in the Democratic Republic of the Congo (DRC) and Sudan, the virus is thought to be transmitted to humans from bushmeat. It is spread through direct contact of broken skin or mucous membranes with bodily fluids such as blood, sweat, semen and other secretions, or with surfaces like bedding and clothing that have been infected with these substances. The current outbreak is caused by the deadliest species of the Ebolavirus (the Zaire strain) and has a 50% fatality rate. Unlike previous instances, the disease has not remained contained within remote rural villages, but has spread to urban areas since the first case was reported in Guinea in March 2014. This has only sped up its transmission to other countries, and it now seriously affects Liberia and Sierra Leone. There are fears that it could develop into a major pandemic, but certain measures can be taken to combat the virus and prevent it from spreading in South Africa.
TL;DR: The present results support the notion of the possible involvement of apoptosis in normal ovarian growth, but do not appear to be restricted to the period prior to and during juvenile testicular ontogenesis, as well as indicating that some forms of non-apoptotic DNA fragmentation were labelled by the TUNEL assay.
Abstract: Gonad development in zebrafish is not well understood. Primordial germ cells, undifferentiated and bi-potential, differentiate into oogonia during early larval development. Thereafter, testicular ontogenesis is initiated through the development of immature oocytes. The primary signal of testicular differentiation remains a mystery. The aim of the research reported in this article was to identify biomarkers for the detection of impending sex inversion in zebrafish. The terminal deoxynucleotidyl transferase mediated dUTP nick end labelling (TUNEL) technique was used to predict impending juvenile sex inversion. Results indicate the presence of TUNEL-positive cells in juvenile and adult ovaries. In juvenile ovaries, ‘growing’ areas revealed intense positive labelling, while in adult ovaries, positive signals were restricted to the nuclei of epithelial/thecal cells, post-pachytene and pre-vitellogenic oocytes. Further, the present research indicated that some forms of non-apoptotic DNA fragmentation were label...