Botany & Zoology
Welcome to Stellenbosch University



More than 600 degrees in the natural sciences awarded at SU’s December graduation than 600 degrees in the natural sciences awarded at SU’s December graduationWiida Fourie-Basson<p>​​​Dressed in traditional Zulu-attire, Maties student Menzi Ngcamphalalala today proudly walked across the stage to receive his MSc degree in Mathematics. He was one of the more than 600 graduate and postgraduate students in the natural sciences who received their degrees during Stellenbosch University's fifth graduation ceremony on 11 December 2019.<br></p><p>Amongst these were a whopping nine PhDs in Chemistry and Polymer Science, while another 29 students received their MSc-degrees in Mathematics as part of the African Institute for Mathematical Sciences' (AIMS) programme. All in all, the Faculty of Science awarded 390 BSc, 145 BScHons, 55 MSc and 29 PhD degrees. <br></p><p>Another MSc student in Mathematics, <a href="/english/Lists/news/DispForm.aspx?ID=7007">Sarah Selkirk​</a>, was also awarded the prestigous S2A3 medal (bronze) of the Southern African Association for the Advancement of Science (SAAAS) for the best MSc student at Stellenbosch University across the natural, engineering and medical sciences.<br></p><p>Prof Louise Warnich, Dean of SU's Faculty of Science, says she is grateful for the hard work put in by lecturers, study leaders and students, despite the many challenges faced by higher education institutions in South Africa. Since 2015, the Faculty of Science has consistently produced more than 300 postgraduate students per year, and it seems the year 2019 will be no exception.</p><p>“Our graduandi continue to make important contributions to the private and public sectors in South Africa, many of them as leaders and entrepreneurs. I am confident that the class of 2019 will follow in their footsteps and apply their hard-earned, high-level skills for the advantage and development of our society."</p><p>Some of the highlights from this year's graduandi include a PhD in Biochemistry awarded to <a href="/english/Lists/news/DispForm.aspx?ID=7005">Dr Collins Jana</a>, currently a lecturer at the University of Malawi's College of Medicine. Back in 2014, when he embarked on a career focusing on research into the development of new drugs to fight infectious diseases, there were no higher education institutions in Malawi offering postgraduate options in biochemistry. That was the start of a ten-year long journey as a postgraduate student in the research group of Prof Erick Strauss in SU's Department of Biochemistry.</p><p>Another highlight is the achievement of Dr Upenyu Lucky Muza, who not only earned a PhD in Chemistry under the supervision of Prof Harald Pasch, but in August this year he was one of only five postgraduate students nation-wide to receive the <a href="">SASOL Postgraduate Medal</a> from the South African Chemical Institute (SACI), awarded to postgraduate students who are innovative, entrepreneurial and independent. Formerly from Zimbabwe, he is off to Europe next year for a postdoctoral fellowship.<br></p><p>Another highlight is a PhD in Computer Science awarded to Dr Arnu Pretorius, who entered the field of machine learning and deep neural networks with a background in statistical mathematics. While many regard algorithms more as an art than a science, he developed a more principled design process in which decision are guided by theoretical developments. <a href="/english/Lists/news/DispForm.aspx?ID=7006">Read more​</a> about his work with study leader Dr Steve Kroon from the Computer Science Division in the Faculty of Science.</p><p>The Department of Botany and Zoology also made their mark this year, with five PhD-students graduating. Dr Luyanda Ndlela isolated and characterized three predatory bacteria that may one day become pivotal in finding natural treatments for toxic algal blooms; Dr Olivier Pasnin, a research scientist at the Mauritius Oceanography Institute, did the first phylogenetic analysis of sponges in the Western Ocean, thereby contributing to improved marine conservation practices. Other PhD graduates looked at the evolutionary history and taxonomy of parasitoid wasps, the drivers of Prosopis invasions in Eastern Africa, and the role of marine predators in regulating invasions.</p><p>Another three PhDs were awarded in Physics, three in Mathematical Science, two in Physiological Sciences and one each in Applied Mathematics and Microbiology</p><p><em>Photos: Stefan Els</em></p>
Shark Safe Barrier™ tested at popular beach resort on La Réunion Island Safe Barrier™ tested at popular beach resort on La Réunion IslandWiida Fourie-Basson<p>​Shark-deterrent technology developed by a team from Stellenbosch University is now being tested of the coast of La Réunion Island in the Indian Ocean.<br></p><p>The <a href="">Shark Safe Barrier™</a> is the most advanced shark-specific deterrent technology currently available that do not injure or kill sharks and other marine animals, while keeping surfers and swimmers safe.<br></p><div class="ms-rtestate-read ms-rte-embedcode ms-rte-embedil ms-rtestate-notify"><iframe width="560" height="315" src="" frameborder="0"></iframe> </div><p><br></p><p>For mobile users <a href="">click here</a>.<br></p><p>The technology has been in development for the past seven years by SU's <a href="">Dr Sara Andreotti and Professor Conrad Matthee</a>, in collaboration with well-known conservationist Michael Rutzen, Dr Craig O'Connel from the USA and South African coastal engineer Laurie Barwell. The team combined two well-known aspects of shark biology, their natural dislike of dense kelp-forests and their sensitivity to magnetic fields, to come up with a barrier that will physically separate sharks and people from each other.</p><p>In practice it consists of several rows of staggered high-density polyethylene pipes that are positioned one meter apart on the sea bed in order to imitate a dense kelp forest. The ocean-facing row contains large ceramic magnets, creating a strong magnetic field to further deter the sharks from entering.</p><p>The concept has been piloted and tested in the stormy waters of Gansbaai, regarded as the mecca of great white sharks in South Africa. During the two years of trials not a single shark have entered an artificially-created kelp barrier of 169 square meters, even though tempted with fish bait and chum.</p><p><strong>Invention to be tested outside South African waters for the first time</strong></p><p>In 2014 the Shark Safe Barrier™ was commercialized with the help of SU's technology transfer company, Innovus.</p><p>Now its chief operating officer, Dr Andreotti was approached in 2017 by <a href="">La Réunion's Shark Risk Management Centre to test their invention's effectiveness with bull sharks in the Indian Ocean</a>.</p><p>“During January and February 2019 we installed a 100 square meter barrier of the coast of Saint-Paul. Twice a week, chum and fish bait are released in the middle of the square by Reunion researchers to lure sharks. The structure has already formed an artificial reef and has become a refuge for local fish, but so far, no sharks has approached the enclosure," she says.</p><p>The field test will be completed after the Réunion team has recorded interactions with at least 20 bull sharks.</p><p>Between 2007 and 2016, this surfers' paradise has seen seven fatal and 14 non-fatal shark incidents, with a subsequent drop in tourist bookings of 40% after each of these unfortunate events.</p><p>“In 2014 tourists totaled almost half of the population on the island. But today the authorities warn residents and tourists to stay out of the water" says Andreotti.</p><p>If successful, the installation of the Shark Safe Barrier™ along this popular coastline could mean a turn-around for the island's ailing tourism industry. </p><p>But, more importantly, it could also mean a turn-around for the <a href="">oceans' threatened shark populations</a>.</p><p>“Between 2011 and 2016, there have been 491 registered shark attacks worldwide, of which 43 proved fatal. Meanwhile, thousands of sea creatures have been killed by getting entangled in shark nets, or fished by drumlines," Andreotti says.</p><p><strong>Crowdfunding for one more test</strong></p><p>The team is currently working on improving the robustness of the Shark Safe Barrier™ technology by adapting the anchorage system to better secure the pipes on sandy sea beds. It then needs to be exposed to real sea condition for one more time.</p><p>For this exercise, the team plans to raise $24 000 through the crowdfunding platform <a href="">Thundafund</a> at <span style="font-size:12pt;font-family:"times new roman", serif;"><a href="" target="_blank"></a></span><br></p><p>If this last test is successful, the Shark Safe Barrier invention is one step closer to be rolled-out to beaches all over the world, to the benefit of both humans and the oceans' marine animals, Andreotti concludes.<br></p><p><strong>Media enquiries</strong></p><p>Dr Sara Andreotti</p><p>E-mail:</p><p>Cell: 27(0)72 321 9198<br></p><p><br></p><p><br></p>
Quantum dots used to capture act of speciation dots used to capture act of speciationWiida Fourie-Basson<p>​​Using quantum dots as a tool to trace the pollen of the long-tubed iris, <em>Lapeirousia anceps</em>, evolutionary ecologists from Stellenbosch University have succeeded in capturing a snapshot of a plant in the process of speciation.</p><p><a href="/english/faculty/science/botany-zoology/research">Professor Bruce Anderson</a>, an evolutionary ecologist in the <a href="/english/faculty/science/botany-zoology">Department of Botany and Zoology</a> at SU, says this is only the third time in his research career where he has found a contact zone where speciation appears to be happening right in front of our eyes.<br></p><p>​“Contact zones of entities in the process of diverging may actually be quite common, but they are hard to find because you really need to know what to look for," he postulates.<br></p><p>For the  past 15 years Anderson and his associates have been visiting a patch of West Coast sand-plain fynbos just outside the small town of Mamre on South Africa's West Coast, a 45 minute drive from Cape Time along the N7 highway.</p><div class="ms-rtestate-read ms-rte-embedcode ms-rte-embedil ms-rtestate-notify"><iframe width="560" height="315" src="" frameborder="0"></iframe> </div><p>​This is one of the prime spots where the long-tubed iris, <em>Lapeirousia anceps</em> can be found, as well as its pollinator, the long-tongue fly, <em>Moegistorhynchus longirostris</em>.</p><p>“Think of the famous example of the Madagascar star orchid with its 30cm nectar tube and <a href="">Darwin's moth</a> with an almost equally long tongue," Anderson explains, “where the orchid and moth have coevolved in an escalating race scenario." </p><p>The same evolutionary mechanism behind matching of pollinator tongues and floral tubes is true for <em>Lapeirousia</em>.<br></p><p>In 2009 a fellow researcher, <a href="">Professor Anton Pauw</a>, found that <em>Lapeirousia</em> has tube lengths which have coevolved with the tongue lengths of its fly pollinator, <em>Moegistorhynchus longirostris, </em>where tongues and tubes can vary from 43-86mm, depending on the study site. In other words, the tube-lengths of the plants match perfectly with the tongue-length of the pollinators, depending on the geographical location of the different populations. </p><p>But in 2003 Anderson stumbled upon a strange population of <em>Lapeirousia anceps</em> in the Mamre area: “Some plants had short floral tubes and others had long tubes, and very few plants had tubes of intermediate length. Yet this population of plants was visited by only a single species of the long-tongued fly, <em>Moegistorhynchus longirostris</em>."</p><p>For the next 15 years, Anderson and his colleagues studied this population and found that there was little gene flow between the two plants forms, which explained why they had remained as two separate entities for so long.</p><p>“In other countries with fewer plant species, biologists would have been sorely tempted to call these forms different species, but we have so many species already that we can afford to be a little more circumspect!" he laughs.</p><p>Anderson was much more interested in finding the mechanisms that prevented the two forms from mixing in the first place.</p><p>On one of the many photographs from his field work, he noticed a long-tongued fly from that area with pollen on the top of its head and then another clump of pollen halfway down its tongue. But because these plants are so recently diverged, they couldn't tell the pollen apart.</p><p>“I was sure that the pollen on the head was from the long-tubed flowers and the other pollen from the short-tubed flowers, but I had no way of showing this."</p><p><strong>Quantum physics to the rescue</strong></p><p>When Corneile Minnaar joined the group as a PhD student in 2015, he decided to try and find a reliable method to label and track pollen in order to answer this question. By the end of his first year, he succeeded in <a href="/english/Lists/news/DispForm.aspx?ID=6231">using quantum dots to label pollen grains</a>, thereby breaking new ground in a field of research that has been hampered by the lack of a universal method to track pollen for over a century.</p><p>During November 2015 and 2016, the team set off to Mamre to test the newly-designed method in the field, and, more importantly, to test Anderson's hypothesis.</p><p>In the case of <em>Lapeirousia</em> and the long-tongued fly, Minnaar and Anderson were now able to show conclusively that long- and short-tubed flowers place and receive pollen on different parts of the fly's long tongue: short tubed flowers mostly midway and long-tubed flowers on or near the head. </p><p>Consequently, pollen seldom moves between long and short tubed individuals, indicating a barrier to the flow of genes.</p><p>Professor Andersons says it looks as if they have captured these plants in the very act of speciation: “This is quite unusual, because normally when you see plants they have diverged long ago and it is very difficult to tell the processes by which they diverged. This is different. We've managed to capture these plants in the act of speciation and we were able to identify the process and mechanisms by which it is taking place."</p><p>He says it is hard to predict whether these two forms of <em>Lapeirousia</em> will remain separate forever or eventually unify. But what he does know is that this patch of land needs to be protected.</p><p>“It is severely threatened, heavily grazed and invaded by acacias and grasses," he warns. “There is a very real possibility for this unique patch of sand-plain fynbos to disappear in the not too distant future."</p><p>The article “<a href="">Intraspecific divergence in floral-tube length promotes asymmetric pollen movement and reproductive isolation</a>" was published in the journal <em>New Phytologist</em> this month, with authors Dr Corneille Minnaar, Dr Marinus de Jager and Professor Bruce Anderson.</p><p><strong>Media enquiries</strong></p><p>Prof Bruce Anderson<br> Department of Botany and Zoology, University of Stellenbosch<br> Tel: (021) 808 3586<br> Cell:  072 113 6948</p><p>E-mail:<br> <a href=""></a></p><p><strong>Captions</strong></p><p>With a tongue up to 7 cm in length, the long-tongue fly <em>Moegistorhynchus longirostris</em> often battle to fly, especially in the wind. The fly must fully insert its proboscis into the flower to obtain a tiny droplet of nectar at the bottom of the tube, and in the process pollen is placed on or removed from its head by the long-tubed iris, <em>Lapeirousia anceps</em>.<strong> </strong><em>Photo: Bruce Anderson</em></p><p><br></p>
From zero to hero for South Africa’s common wood sorrel zero to hero for South Africa’s common wood sorrelWiida Fourie-Basson<p>Over the past 15 million years South Africa's common wood sorrel has developed an arsenal of the most unique and extreme germination strategies in the Cape Flora.<br></p><p>Yet the same strategies that have allowed these delicate little plants to grow and survive in the most uninhabitable places thinkable – think of the <a href="">Richtersveld</a>, <a href="">Knersvlakte</a>, <a href="">Oorlogskloof </a>and Gifberg – may now be to its detriment under a fast changing climate.</p><p>In a study published in the <a href=""><em>American Journal of Botany</em></a> recently, Dr Michelle Jooste from the Department of Botany and Zoology at Stellenbosch University describes a continuum of germination states for 64 species of <em>Oxalis</em>: from germinating within 24 hours (called recalcitrant seeds) to lying dormant for several years, while waiting for the ideal environmental conditions to germinate (called orthodox seeds).</p><p><a href="/english/Lists/news/DispForm.aspx?ID=4468">Prof Léanne Dreyer</a>, one of the co-authors and a leading expert on southern African <em>Oxalis</em>, says the wood sorrel's germination strategies are nothing short of weird, extreme and unique in the plant kingdom.</p><p><em>“Oxalis</em> had to adapt to a Mediterranean climate subjected to long hot and dry summers alternating with a very predictable wet winter rainfall season. Dealing with these two extremes, which have remained stable for the past 15 million years, enabled <em>Oxalis</em> to take germination strategies to a whole new level," she explains.</p><p>Even more unique is the incidence of inverse germination in some <em>Oxalis</em> species, where the seed leaves and the first foliar leaf develop rapidly and appear to sustain rapid growth of the seedling before the radicle and root hairs subsequently emerge.</p><p>“This is a remarkable phenomenon," says Dreyer, “and it is happening at the speed of light, as the plant needs to have enough time and produce sufficient resources within a single growing season to also form a bulb in order to survive underground during the hot, dry summer months."<br></p><p><img src="/english/faculty/science/PublishingImages/News%20items/Oxalis%20germination_Facebook.png" class="ms-rtePosition-4" alt="" style="margin:5px;width:497px;" /><br>​But it doesn't end here. The researchers have noticed that some of the recalcitrant species produce large amounts of a thick gluey substance (called mucilage) upon germination. They are now investigating the presence of bacteria in the mucilage, which appear to be symbiotically associated with these seeds – a symbiosis is when two or more organisms live together in a close mutually beneficial association.<br></p><p>Even more extreme are those <em>Oxalis</em> species of which the seeds are capable of either rapid germination or staying dormant: “These seeds have the benefit of immediate germination if environmental conditions are favorable, or to delay germination until conditions become more favorable," Dreyer explains.</p><p>These types of seeds are extremely rare. In the case of <em>Oxalis</em>, only 19% of the 64 species studied – selected to be as representative as possible of the nearly 230 known southern African <em>Oxalis</em> species – displayed intermediate germination.</p><p>Intermediate and recalcitrant species (56%) are almost exclusively restricted to the winter rainfall areas of the Cape, while orthodox species (24%) are present in both summer and winter rainfall areas.</p><p>Dreyer says they regard the orthodox strategy as the ancestral state among <em>Oxalis</em> species. The big question now is whether <em>Oxalis</em> has one more survival strategy in its arsenal to deal with drier conditions and a less predictable winter rainfall in the Cape Floristic Region as predicted by models of future climate change.</p><p>“If not, we stand to lose more than 50% of Cape <em>Oxalis</em> species – that is more than 115 species!" she concludes.</p><ul><li>The article “<a href=""><em>Oxalis</em> seeds from the Cape Flora have a spectrum of germination strategies</a>" was published in the <em>American Journal of Botany.</em> The authors are Dr Michelle Jooste, Professor Guy Midgley and Professor Léanne Dreyer from Stellenbosch University, and Dr Kenneth Oberlander from the University of Pretoria. <br></li></ul><div><br></div><div><strong>On the photo above</strong>, within 24 hours, a day-old seedling of <em>Oxalis gracilis</em> with opened seed leaves between which the first foliar leaf is starting to develop. Note that the radicle is still completely underdeveloped, and the seedling is imbedded in a mucilage. <em>Image: Léanne Dreyer</em><br></div><div><em><br></em></div><div><p><strong>Media enquiries</strong></p><p>Prof Léanne Dreyer</p><p>Department of Botany and Zoology, Stellenbosch University</p><p>Tel: +27 _21 808 3070</p><p>E-mail: <a href=""></a><br></p></div><p><br></p>
Genetic blueprint for extraordinary wood-munching fungus from the Northern Cape blueprint for extraordinary wood-munching fungus from the Northern CapeWiida Fourie-Basson<p>A relatively unknown fungus, accidentally found growing on an Acacia tree in the Northern Cape, has emerged as a voracious wood-munching organism with enormous potential in industries based on renewable resources.<br></p><p>The first time someone took note of <a href=""><em>Coniochaeta pulveracea</em></a> was more than two hundred years ago, when the South African-born mycologist Dr <a href="">Christiaan Hendrik Persoon</a> mentioned it in his 1797 book on the classification of fungi.</p><p>Now <em>C. pulveracea</em> has had its whole genome sequenced by microbiologists at Stellenbosch University (SU) in South Africa, and henceforth made its debut in cyberspace with a few <a href="">tweets</a> and a hashtag. All because this relatively unknown fungus has an extraordinary ability to degrade wood – hence the descriptor “<em>pulveracea"</em>, meaning powdery.<img src="/english/PublishingImages/Lists/dualnews/My%20Items%20View/cpulveracea%20small.jpg" alt="cpulveracea small.jpg" class="ms-rtePosition-2" style="margin:5px;" /><br></p><p>In the age of biotechnology, biofuels and the usage of renewable raw materials, this is an important fungus to take note of, says <a href="/english/faculty/science/microbiology/research/a-botha">Prof Alf Botha</a>, a microbiologist in the <a href="/english/faculty/science/microbiology">Department of Microbiology</a> at SU.</p><p>Over the past 25 years, there has been a number of reports on the ability of species in the <em>Coniochaeta</em> genus to rapidly degrade lignocellulose into fermentable simple sugars. But thus far Prof Botha's lab is the only one to be working on <em>C. pulveracea</em>.</p><p>The work started in 2011, when he quite randomly snapped a brittle twig, covered in lichen, from a decaying Acacia tree. At the time, he was holidaying with family on a farm in the Northern Cape. “At the time we were looking for fungi and yeasts that can break down wood, so I knew this was something special when I decided to keep the twig," he explains. But to date, despite numerous attempts, they have not been able to find it again.</p><p>However, back in the lab there was great excitement when they observed that this species in the <em>Coniochaeta</em> genus was literally munching its way through birchwood toothpicks. Even more astounding was its ability to change form between a filamentous fungus and a yeast, depending on the environment.</p><p>“This is highly unusual for a fungus. We'd typically expect this kind of behavior from some fungal pathogens," explains Botha.</p><p>Over the past decade Botha and his postgraduate students focused on unraveling this yeast-like fungus' behavior. In 2011 Dr Andrea van Heerden found that it produced enzymes that degraded the complex structures of wood into simple sugars, feeding a community of surrounding fungi that do not have the ability to degrade wood. In 2016, she published the results of her investigation into its ability to switch to a yeast-like growth. Understanding this process would be important to the potential use of this fungi in industrial processes.</p><p>In the latest study, MSc student CJ Borstlap worked with <a href="/english/faculty/science/microbiology/research/h-volschenk">Dr Heinrich Volschenk</a> , an expert molecular biologist, and Dr Riaan de Witt from the <a href="/english/faculty/science/sci-bioinformatics">Centre for Bioinformatics and Computational Biology</a> at SU, to produce the first draft genome sequence of <em>C. pulveracea</em>. With a genome size of 30 million nucleotides and over 10 000 genes, this was no easy task. In the process he picked up the necessary coding skills to identify and name all 10 053 genes, and to identify those responsible for the wood-degrading character of the fungus.</p><p>Dr Volschenk says the next step is to understand the fungus' mechanism of breaking down wood and producing sugars on a molecular level: “With the genetic blueprint now available, we can study the network of genes and proteins the fungus employs to convert wood and other similar renewable resources into more valuable products," he explains.</p><p>The sequence data for <em>C. pulveracea</em> have been deposited at the DNA Data Bank of Japan (DDBJ), the European Nucleotide Archive (ENA) at Cambridge, and GenBank in the United States of America, under the accession number QVQW00000000 and is freely available to all researchers in this field.</p><p>The article “Draft Genome Sequence of the Lignocellulose-Degrading Ascomycete <em>Coniochaeta pulveracea</em> CAB 683" was published in the American Society for Microbiology's journal <em>Microbiology Resource Announcements</em> on 3 January 2019 and is available online at <a href=""></a></p><p><strong>On the photos above:</strong></p><p>Cells of the wood-eating fungus, <em>Coniochaeta pulveracea</em>, exhibit both yeast- and fungus-type characteristics while breaking down twigs from an Acacia tree. Image: Heinrich Volschenk</p><p>Microbiologists from Stellenbosch University produced the first whole genome sequence of the wood-eating fungus, <em>C. pulveracea</em>. This relatively unknown and hard-to-find fungus has emerged as a voracious wood-munching organism with enormous potential in industries based on renewable resources. They are, from left to right, Prof Alf Botha, MSc-student CJ Borstlap, Dr Heinrich Volschenk and Dr Riaan de Witt. Photo: Stellenbosch University</p><p><strong><br></strong></p><p><strong>Media enquiries</strong></p><p>Prof Alf Botha</p><p>Department of Microbiology, Stellenbosch University</p><p>Tel: +27 021 808 5856</p><p>E-mail. <a href=""></a></p><p> <br></p><p>Dr Heinrich Volschenk</p><p>Department of Microbiology, Stellenbosch University</p><p>Tel: +27 021 808 5851</p><p>E-mail: <a href=""></a></p><p> </p><p>Mr CJ Borstlap</p><p>Mobile: 0784122262</p><p>E-mail: <a href=""></a><br><br></p>
Quantum dots used to track flowers’ pollen dots used to track flowers’ pollenWiida Fourie-Basson​A pollination biologist from <a href="/english/">Stellenbosch University</a> is using quantum dots to track the fate of individual pollen grains. This is breaking new ground in a field of research that has been hampered by the lack of a universal method to track pollen for over a century.<p>In an article published in the journal <a href=""><em>Methods in Ecology and Evolution</em></a> this week, <a href="">Dr Corneile Minnaar</a> describes this novel method, which will enable pollination biologists to track the whole pollination process from the first visit by a pollinator to its endpoint – either successfully transferred to another flower's stigma or lost along the way.<br></p><div class="ms-rtestate-read ms-rte-embedcode ms-rte-embedil ms-rtestate-notify"><iframe width="560" height="315" src="" frameborder="0"></iframe> </div><p>(<a href="">Mobile users click here</a> for video)<br></p><p>Despite over two hundred years of detailed research on pollination, Minnaar says, researchers do not know for sure where most of the microscopically tiny pollen grains actually land up once they leave flowers: “Plants produce massive amounts of pollen, but it looks like more than 90% of it never reaches stigmas. For the tiny fraction of pollen grains that make their way to stigmas, the journey is often unclear—which pollinators transferred the grains and from where?"</p><p>Starting in 2015, Minnaar decided to tread where many others have thus far failed, and took up the challenge through his PhD research in the Department of Botany and Zoology at Stellenbosch University (SU).</p><p>"Most plant species on earth are reliant on insects for pollination, including more than 30% of the food crops we eat. With insects facing rapid global decline, it is crucial that we understand which insects are important pollinators of different plants—this starts with tracking pollen," he explains.</p><p>He came upon the idea for a pollen-tracking method after reading an article on the use of quantum dots to track cancer cells in rats (<a href=""></a>). Quantum dots are semiconductor nanocrystals that are so small, they behave like artificial atoms. When exposed to UV light, they emit extremely bright light in a range of possible colours. In the case of pollen grains, he figured out that quantum dots with “fat-loving" (lipophilic) ligands would theoretically stick to the fatty outer layer of pollen grains, called pollenkitt, and the glowing colours of the quantum dots can then be used to uniquely "label" pollen grains to see where they end up.</p><p>The next step was to find a cost-effective way to view the fluorescing pollen grains under a field dissection microscope. At that stage Minnaar was still using a toy pen from a family restaurant with a little UV LED light that he borrowed from one of his professors.</p><p>“I decided to design a fluorescence box that can fit under a dissection microscope. And, because I wanted people to use this method, I designed a box that can easily be 3D-printed at a cost of about R5,000, including the required electronic components."</p><p>So far, the method and excitation box have proven itself as an easy and relatively inexpensive method to track individual pollen grains: “I've done studies where I caught the insects after they have visited the plant with quantum-dot labelled anthers, and you can see where the pollen is placed, and which insects actually carry more or less pollen."</p><p>But the post-labelling part of the work still requires hours and hours of painstaking counting and checking: “I think I've probably counted more than a hundred thousand pollen grains these last three years," he laughs.</p><p>As a postdoctoral fellow in the research group of <a href="">Prof Bruce Anderson</a> in the <a href="/english/faculty/science/botany-zoology/Pages/default.aspx">Department of Botany and Zoology</a> at Stellenbosch University, <a href="">Minnaar </a>will continue to use the method to investigate the many unanswered questions in this field.</p><p>The article, “Using quantum dots as pollen labels to track the fate of individual pollen grains" was published on Wednesday, 13 February 2019, in the journal <em>Methods in Ecology and Evolution</em> and is available online at <a href=""></a> (an earlier non-peer reviewed version of the article is available for free on bioRxiv: <a href=""></a>)<br></p><p><em>On the photo above (left), </em><em>Dr Corneile Minnaar, a pollination biologist in the Department of Botany and Zoology at Stellenbosch University, developed a technique which uses quantum dots to track individual pollen grains, thereby breaking new ground in a field of research that has been hampered by lack of a universal method to track pollen for over a century. </em><em>Photo: Stefan Els</em><br></p><p><i>On the photo (right), Pollen grains, labelled with green, yellow, and red quantum dots, on a stigma and viewed viewed here inside the excitation box. Files for 3D-printing the box can be found online at <a href=""></a>. <em>Photo: Corneile Minnaar</em></i></p><p>​​ </p><p><strong>Media enquiries</strong></p><p>Dr Corneile Minnaar</p><p>Department of Botany and Zoology, Stellenbosch University</p><p>Tel: 082 313 0725</p><p>E-mail:</p><p style="text-align:center;"><em>Media release issued by Wiida Fourie-Basson, Media: Faculty of Science, Stellenbosch University, South Africa</em></p><p style="text-align:center;"><em>+27 021 808 2684</em><em>        </em><a href=""><em></em></a><em>           </em><em>@scienceSUN​</em></p>
African Union recognises SU world leader in invasion biology Union recognises SU world leader in invasion biologyMedia & Communication, Faculty of Science<p>Prof Dave Richardson from the <a href="">DST-NRF Centre of Excellence for Invasion Biology</a> (CIB) at Stellenbosch University (SU) and a world leading scientist in the field of invasion biology, is the recipient of the 2018 <a href="">Kwame Nkrumah Award for Scientific Excellence</a>.<img src="/english/PublishingImages/Lists/dualnews/My%20Items%20View/David%20Richardson-15_small.jpg" alt="David Richardson-15_small.jpg" class="ms-rtePosition-2" style="margin:5px;width:281px;" /><br></p><p>This continental award is one of three awards made annually by the <a href="">Commission of the African Union</a> to recognise outstanding African scientists for their achievements, discoveries and innovations. Established in 2008 in memory of the well-known Pan-Africanist leader Dr Kwame Nkrumah, the continental award includes a monetary award of US$100 000.</p><p><a href="">Prof Richardson</a> is a distinguished professor in the Department of Botany and Zoology at SU, James Marsh Professor-at-Large at the University of Vermont in the United States of America, and director of the CIB, one of the most productive and influential research groups working in the field of biological invasions in the world. Biological invasions are a rapidly growing threat to biodiversity and ecosystem functioning in Africa and many parts of the world.<br></p><p>Prof Richardson says he is extremely honoured to receive this award: “I hope that it will help to spread awareness of the massive problems with invasive species worldwide, and the urgent need for innovative solutions to prevent the escalation of impacts on biodiversity and human livelihoods."</p><p>He also commended South Africa's Department of Science and Technology and Stellenbosch University for their substantial investments in this field through their funding of the CIB: “The Centre has created a critical mass of knowledge and expertise across disciplines to address diverse issues pertaining to biological invasions in Africa."<br></p><p>Prof Louise Warnich, Dean of the Faculty of Science, says the award is yet another well-deserved recognition of Prof Richardson's significant contributions to the field of invasion biology: “The awards confirms his status as an influential international leader in this field. The CIB has continued to blossom under his leadership and he is an excellent role model for young researchers."</p><p>The Award Ceremony will be held at the AU Conference Center on 10 February 2019 during the Assembly of the AU Heads of States (The Summit) in Addis Ababa, Ethiopia.</p><p><strong>More about Prof Richardson</strong></p><p>Prof Richardson is regarded as one of the most influential authors globally in the field of invasion science. His research focusses on biological invasions, and in particular the dynamics of plant invasions, specifically trees and shrubs. He has worked predominantly on invasive species in South Africa, mainly in the fynbos and savanna biomes, but has also published widely on invasive species in other parts of Africa and the world, on global patterns and trends in biological invasions, and on developing a sound theoretical basis for invasion science.</p><p>One of his major contributions to invasion science has been the thorough development and exploitation of new model systems for the elucidation of all the diverse perspectives that need to be considered to understand and manage invasive species. His contributions on the ecology of pines and Australian acacias are widely recognised as foundation studies in invasion science.</p><p>Prof Richardson has also contributed substantially to the formulation of practical guidelines for the improved management of invasions. He is frequently consulted by conservation agencies and government departments, and serves on various committees related to environmental management in South Africa and abroad.</p><p>He is currently one of only a handful of African scientists rated as a “Highly Cited Researcher" by Clarivate Analytics – these are scientists who rank in the top 1% by citations for their field in the Web of Science and are making an impact in solving some of the world's biggest challenges. He has received numerous awards, including the Hans Sigrist Prize (2006), the John F.W. Herschel Medal from the Royal Society of South Africa (2012), and the Havenga Prize for Life Sciences from the South African Academy for Science and Arts (2013). In 2019 he received a third successive A1 rating from the National Research Foundation, reflecting his status as a world leader in invasion science.<br></p><p><em>On the photo, Prof Dave Richardson. Photographer: Anton Jordaan</em></p>
New crab species discovered in Eastern Cape ‘forgotten’ forests crab species discovered in Eastern Cape ‘forgotten’ forestsDane McDonald<p>​A new 'pearl white' freshwater crab species has been discovered in the 'forgotten' Eastern Cape forests of South Africa.<br></p><p>Prof Savel Daniels, a molecular taxonomist at Stellenbosch University, says crabs are relatively well studied in South Africa but for some reason forests have been neglected in sampling efforts.</p><p>“Nobody has ever intensively sampled the forests in the Eastern Cape where we (incidentally) found the species at Mbotyi," he told the FBIP.</p><p>The study formed part of the Eastern Cape Forest project, one of the Large Integrated Projects funded by the Foundational Biodiversity Information Programme (FBIP).</p><p>Mbotyi is a picturesque forested region northeast of Port St Johns and adjacent to the East Coast of South Africa.</p><p><strong>'Sympatry'</strong></p><p>The crab, which shimmers in the presence of light, was collected from under stones found in small streams which flow towards the coast.</p><p>In a case of what phylogeographers call 'sympatry' the pearl white crab lives alongside a known rust brown species belonging to the African freshwater crab genus <em>Potamonautes.</em></p><p><em><img class="ms-rtePosition-2" src="/english/faculty/science/PublishingImages/News%20items/Crabfigure5.jpg" alt="" style="margin:5px;width:300px;" /></em> </p><p>Like a divorced couple who still share the same house, the two related [but genetically distinct] populations are sympatric because they exist in the same geographic area and thus frequently encounter one another without breeding.</p><p>In a sense Daniels was lucky to have discovered the specimen with its striking colour difference compared to its counterpart, <em>P. sidneyi</em>. </p><p>In recent times and particularly with invertebrates, such discoveries, where the scientist has a clear morphological difference as a 'lead' for identifying a potential new species, are rare.</p><p><strong>'Colour morphs'</strong></p><p>In Daniels' line of work he often encounters 'cryptic species' where animals which are similar to the human eye are genetically very different. In other cases animals look different but show no significant genetic differences – different 'morphs'.</p><p>Daniels set out to answer whether the two crabs were indeed different species, or less spectacularly, two superficial 'colour morphs' with the one being pearl white and the other rust brown.</p><p>Back in the laboratory at the Stellenbosch University Evolutionary Genomics Facility samples from both groups of animals were subjected to DNA sequencing, looking at three genes known by geneticists as 'COI, 12S rRNA, and 16S rRNA'.</p><p><strong>DNA sequence divergence</strong></p><p>The DNA sequence divergence (i.e. the genetic difference) for the COI gene, usually a primary marker in animal genetic studies, was striking at 13.42%. </p><p>To gain a better perspective on divergence values molecular taxonomists need to look at which values from prior studies were used to designate something as sufficiently different to be called a 'new species'. </p><p>Daniels' paper, published in the <em>Journal of Crustacean Biology</em>, cited two prior studies with values ranging from 2.8% to 14.7% in the one, and 7.9% between two species in the other.</p><p>There could be no doubt that the shimmering pearl white specimen from Mbotyi was a new species to science.</p><p>Daniels found no morphological characteristics with which to distinguish <em>P. sidneyi</em> from the new Mbotyi species except for the striking colour difference. The latter was inspiration for the naming of the new species, one of the few opportunities for creativity in describing a new species.</p><p>As a tribute to the Xhosa people of the Mbotyi region Daniels decided to give the newly discovered crab the species epithet of <em>mhlophe</em>, meaning 'white' in isiXhosa.</p><p>He says the discovery is important as it highlights the biodiversity of the area, and further establishes the region as a 'biodiversity hotspot', a tourism draw card.</p><p>“Tourism in the region creates a lot of sustainable job opportunities," he says.</p><p>The Foundational Biodiversity Information Programme (FBIP) is a long-term programme to generate, manage and disseminate foundational biodiversity information and knowledge to improve decision-making, service delivery and create new economic opportunities.</p><ul><li>FBIP on Facebook and Twitter<br></li></ul><p>For more details contact:</p><p>Contact:             Dane McDonald  </p><p>Designation:     Science communicator</p><p>Cell:                 +27 (0) 72 1299 649</p><p>Email Address:</p><p>Website:                 <br></p><p><br> </p>
Invasive pines fueled Knysna fires pines fueled Knysna firesWiida Fourie-Basson<p>​​The replacement of natural fynbos vegetation with pine plantations in the southern Cape, and the subsequent invasion of surrounding land by invasive pine trees, significantly increased the severity of the <a href="">2017 Knysna wildfires</a>.</p><p>This is one of the findings of a study published in the journal <a href=""><em>Fire Ecology</em></a> by a research team from the <a href="">DST-NRF Centre of Excellence for Invasion Biology</a> (CIB) at Stellenbosch University, Nelson Mandela University, SANParks, and the CSIR. The aim of the study was to assess the climatic, weather and fuel factors that contributed to one of the region's worst fires ever recorded. </p><p>Over four days in June 2017, the Knysna fires burnt 15000 hectares, claiming the lives of seven people and destroying more than 5000 hectares of commercial pine plantations and over 800 buildings. </p><p>The researchers used satellite imagery to compare the landscape before and after the fire, including the type of vegetation covering the different areas. This information enabled them to estimate the amount of biomass consumed by the 2017 fire. </p><p>One of the main findings is that the severity of the fire was significantly higher in plantations of invasive alien trees and in fynbos invaded by alien trees, than in uninvaded fynbos. And while the weather conditions were extreme, they were not unprecedented, as similar conditions occurred in the past at a rate of approximately one day every three years. The severity of the 18-24 month drought that preceded the fires, on the other hand, was higher than ever recorded in the historical weather record, and this contributed significantly to the impact of the fire.</p><p>Prof. Brian van Wilgen, a fire ecologist with the CIB and one of the co-authors, says large tracts of natural vegetation in the southern Cape have been systematically replaced with plantations of <em>Pinus</em> and <em>Eucalyptus</em> species, increasing above-ground biomass from about four to 20 tonnes per hectare: “Given that more than two-thirds of the area that burned was in one of these altered conditions, our findings demonstrate clearly that fuel loads have substantially increased compared to earlier situations when the landscape would have been dominated by regularly burned uninvaded natural vegetation."</p><p>It is estimated that pine trees have invaded more than 90% of the Garden Route National Park's fynbos vegetation at various densities. Additional invasions by Australian <em>Acacia</em> and <em>Eucalyptus</em> species cover a further 29% and 14% respectively: “By increasing the amount of fuel available to burn, the fires become more intense and more difficult to control," he explains.</p><p>Van Wilgen warns, however, that events of this nature can become more frequent as the climate of the southern Cape becomes more hot and dry, and as the extent of invasions increases.</p><p>“The conditions that exacerbated the severity of the 2017 Knysna fires will occur again. People need to stay vigilant and implement fire-wise practices, and, more importantly, steer away from placing developments in high-risk areas in the long inter-fire periods.</p><p>“Our study underscores the need to implement effective programs to control the spread of invasive alien plants, and to re-examine the economic and ecological sustainability of commercial planting of invasive alien trees in fire-prone areas." </p><p>Some of the other finding include:</p><ul><li>The Knysna fires burned 14 958 hectares, of which one third comprised natural vegetation.</li><li>Of the land in the altered category, most (78%) was either commercial plantations of invasive alien trees (52%), or other land invaded by alien plants (26%).</li><li>A relatively small proportion of the burned area was natural forests (4%), or thicket (2%).</li></ul><ul><li>A policy of regular prescribed burning, practiced by the Department of Forestry in the 1970s and 1980s with the dual goals of rejuvenating the fire-dependent vegetation and reducing fuel loads, were halted in the late 1980s. Fire management then shifted to a focus on fire suppression to protect forestry plantations and residential developments, resulting in substantial fuel build-ups in natural vegetation. Leaving fynbos unburnt for long periods can treble the fuel loads, as has been shown in studies elsewhere. In addition, invasion of these areas can further increase fuel loads by 50 to 60%.</li><li>The Knysna's population grew by over 70% over the past 20 years, from 43 000 people to 74 000 people in 2018.</li></ul><p>The paper “An assessment of climate, weather, and fuel factors influencing a large, destructive wildfire in the Knysna region, South Africa" was published in <em>Fire Ecology</em> in August 2018 and is available online at <a href=""></a></p><p>The authors are Dr Tineke Kraaij, Nelson Mandela University, Mr Johan Baard, SANParks, Mr Jacob Arndt, University of Minnesota Twin Cities, Mr Lufuno Vhengani, Meraka Institute, CSIR, and Prof. Brian van Wilgen, DST-NRF Centre of Excellence for Invasion Biology, Stellenbosch University.</p><p><strong>Captions</strong></p><p>A burned-out plantation near Harkerville, shortly after the 2017 Knysna wildfire. Photo: Johan Baard</p><p>Orderly plantations of pine trees in the background, and invasion by escaped pines on the <a href="">Garcia Pass</a> in the southern Cape. These invasions can substantially increase fuel loads, leading to more intense and damaging wildfires. <em>Photo: Brian van Wilgen</em></p><p><strong>Media interviews</strong></p><p>Prof. Brian van Wilgen</p><p>Tel: 021 808-2835; Cell: 082 454 9726</p><p><br> </p>
Launch of the Digital Marloth Collection of the Digital Marloth CollectionWiida Fourie-Basson<p>A precious collection of the original botanical illustrations prepared for printing between 1912 and 1932 in Rudolf Marloth's <em>Flora of South Africa</em>, has now been digitalised by the Stellenbosch University Library.</p><p>The collection of 176 plates contains the original illustrations by botanical artists such as Ethel May Dixie (1876-1973), Esther Smith (1878-1954), Florence Amy Thwaits and Peter McManus, with handwritten notes and instructions for the printers by Marloth. </p><p>Marloth (1855-1931) is regarded as one of South Africa's greatest early botanists. He was a chemist and pharmacist who emigrated from Germany to the Cape of Good Hope in 1883. It is said that on the very first day of arriving in the Cape, he climbed Table Mountain and started collecting plants. Marloth's association with Stellenbosch University started in 1888, when he was appointed as lecturer in Chemistry and Experimental Physics at the then Victoria College, the forerunner of Stellenbosch University today. In 1922 Stellenbosch University awarded him with an Honorary Doctorate in recognition of his contribution to the understanding and knowledge of the Cape Floral Kingdom.</p><p>Over the years, the Marloth family donated several of the original illustrations and plates to the Stellenbosch University Library. This collection has now been taken up in the SUNDigital Collections of the library. The Special Collections Division of the library also hosts many of his personal documents, correspondence and photographs.</p><p>Ms Ellen Tise, senior director of the SU Library, says the preservation of and access to these materials will contribute to future research, not only at Stellenbosch University but worldwide.</p><p>The formal launch of the Marloth Digital Collection will take place on Tuesday 31 July in the Africana Room, Stellenbosch University Library. During this occasion, the botanist Dr Piet Vorster, botanical artist Vicki Thomas and evolutionary ecologist Professor Anton Pauw will talk about the value of botanical collections such as this one from a scientific and artistic perspective.</p><p> <em>On the photos above, Rudolf Marloth, one of the South Africa's greatest early botanists, did much to introduce the rest of the world to the beauty of the Cape Floral Kingdom. </em><em>Photo: Stellenbosch University Library</em></p><p><em>Marloth was the first botanist to describe the pollinator of the Red Disa – the butterfly Meneris tulbaghia, better known as the Pride of Table Mountain. This is also the Western Cape's official flower. Image: </em><em>Marloth Digital Collection, Stellenbosch University Library.</em></p><p><strong>Media enquiries</strong></p><p>Marié Theron</p><p>Information librarian: Natural Sciences, Stellenbosch University Library</p><p>Tel. 021 808 4430</p><p>E-mail:<br></p>