Invasive plants have a much bigger impact than we imagine

Invasive plants have a much bigger impact than we imagine

Authors Susana Clusella-Trullas physiological ecologist at the C·I·B, Stellenbosch University Raquel A Garcia Postdoctoral fellow at the CIB, Stellnbosch University, Stellenbosch University Disclosure statement Susana Clusella-Trullas receives funding from National Research Foundation, South Africa. Raquel A Garcia receives funding from the Centre of Excellence for Invasion Biology (CIB). Stellenbosch University provides support as an endorsing partner of The Conversation AFRICA. The Conversation is funded by Barclays Africa and seven universities, including the Cape Peninsula University of Technology, Rhodes University and the Universities of Cape Town, Johannesburg, Kwa-Zulu Natal, Pretoria, and South Africa. It is hosted by the Universities of the Witwatersrand and Western Cape, the African Population and Health Research Centre and the Nigerian Academy of Science. The Bill & Melinda Gates Foundation is a Strategic Partner. more Republish this articleRepublish our articles for free, online or in print, under Creative Commons licence. Invasive pine trees in the Western Cape have affected lizards causing their numbers to drop significantly. Author supplied   This article is the fifth in a series The Conversation Africa is running on invasive species. Most people would agree that invasive plants are unwanted. Invasive plants are plants that are intentionally or accidentally introduced by humans into areas outside of their natural habitat. These species can spread rapidly with negative consequences for native species. Invasive plant species have an impact on the diversity of local species, they affect water availability and damage the quality of soil nutrients. Once an alien plant has invaded a habitat, it changes the conditions of that environment. It does so by changing the light, solar radiation and temperature levels in the invaded patches. The quality and availability of food, shelter, nest sites, basking sites and perches are changed for a number of animals. They can also inflict big changes on native vegetation, altering the frequency of fires, nutrient cycling, water availability and soil erosion. For example, pine trees in the Western Cape Province of South Africa have spread beyond forestry plantations and invaded native fynbos habitat. In these invaded landscapes, the temperatures available to lizards for functioning optimally are generally cooler and the number of lizard species greatly reduced. In a few cases, some benefits of alien plants have been reported. For example, they can provide fire wood for local communities or add resources for animal species. But these benefits typically do not surpass the negative effects. Invasive plants have an impact on native species through complex interactions and processes. Unless these factors are properly understood, it is difficult to predict what sort of impact invasive plants will have. How much is known about these processes in South African habitats, where invasive alien plants are a key concern? To find the answer, we read all the studies on the impact...

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April Birthdays.

April Birthdays.

Wishing the following members a very happy birthday, may the day be filled with love and laughter. 2nd  ~  Dee Reddan 3rd   ~  Pat Mainwaring 4th  ~   Ally Clough 14th  ~  Sylvia Codita 11th  ~  Hilary Haarhoff 14th  ~  Val Williamson 16th  ~  Gudrun Cox 22nd  ~   Angela MacKey 25th  ~   Louise Lok 26th  ~ Helen Jacoby               Share this:Click to email this to a friend (Opens in new window)Click to print (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on Twitter (Opens in new window)Click to share on Reddit (Opens in new...

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How to Make Best Natural Bug Spray  

How to Make Best Natural Bug Spray  

Every garden, big or small, requires the managing of insects and other pests. Good planning, healthy plants and good combination planting are the first lines of defense against undesired pests. When you are faced with an incoming pest problem, sometimes you just need to SPRAY! Here are the best sprays and methods we know of. Pest Spraying Tips Never use spray on plants during hot sunny weather as it may cause the leaves to burn. Natural soap is tolerated by plants better than detergent (which may have other ingredients such as surfactants, enzymes and softeners added). Decide what you need to do and do no more. For example, do you want to kill the wretched caterpillars that are making a mess of your cabbages? Right, get the biggies by hand and/or make up a strong killer mix and stop them in their munchy tracks! From then on you should be able to keep an eye out and use only a mixture that deters or repels the butterflies or moths from landing to lay eggs. Always remember you want a garden teeming with life with the many insects and creatures keeping each other in check without you rocking the boat too much. Yes you want wonderful vegetables, flowers and trees to eat and enjoy; so practice diversity and don’t aim for perfection and neatness. Even when using natural sprays, do as little harm as possible and don’t try to outgun nature. Here are the best non-toxic organic garden pest control solutions: Garlic Fire Spray Garlic fire spray is the stuff of legend. There are many recipes, but they consist of some or all of the following: garlic, chilli peppers, soap, vegetable oil, kerosene and water. Don’t leave home without a concoction of this. Depending on its strength it will slay dragons and ants 2-3 garlic bulbs (about 6-10 cloves per bulb) 6 large or 12 smaller hot chilli peppers (any variety will do, or if unavailable try 1-2 tablespoon hot chilli powder) 1 tablespoon vegetable oil 3 squirts of liquid detergent (approximately 1 dessertspoonful) 7 cups water. (Use about 2-3 cups in the blender, and top up with the rest later) Put the whole lot into a blender and vitamize well, then strain through muslin, a coffee filter or similar. Pour what you need into a spray bottle for use and keep the rest in jars with lids on in a cupboard or on a shelf somewhere, well labeled. Experiment with it if necessary and check for results or any damage to young plants. If it fixes the problem and your plants are happy, you’ve got the perfect mix, but if there’s still a few biggie pests, albeit struggling, then...

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A tiny beetle and its deadly fungus is threatening South Africa’s trees.

A tiny beetle and its deadly fungus is threatening South Africa’s trees.

Calling all gardeners to watch out for this beetle. Details including photographs of the symptoms, GPS coordinates or a street address, the host tree species and the reporter’s contact details can be sent to diagnostic.clinic@fabi.up.ac.za. You can also contact your Municipality’s Environmental Department. What does it look like?  What does the damage  look like?   February 27, 2018 5.21pm SAST Author Wilhelm de Beer Associate Professor, University of Pretoria Disclosure statement Wilhelm de Beer receives funding from National Research Foundation, Tree Protection Co-operative Programme, and the DST-NRF Centre Of Excellence In Tree Health Biotechnology. University of Pretoria provides funding as a partner of The Conversation AFRICA. The Conversation is funded by Barclays Africa and seven universities, including the Cape Peninsula University of Technology, Rhodes University and the Universities of Cape Town, Johannesburg, Kwa-Zulu Natal, Pretoria, and South Africa. It is hosted by the Universities of the Witwatersrand and Western Cape, the African Population and Health Research Centre and the Nigerian Academy of Science. The Bill & Melinda Gates Foundation is a Strategic Partner. more Republish this articleRepublish our articles for free, online or in print, under Creative Commons licence. The polyphagous shothole borer is tiny – but a fungus it’s commonly associated with can be deadly for trees. Wilhelm de Beer   Sandton is Johannesburg’s economic hub – home to numerous companies’ headquarters and the Johannesburg Stock Exchange. And now it has a new, unwelcome resident: a tiny beetle that could lay waste to several tree species found in the suburb and potentially the wider Johannesburg area. This is particularly concerning, as Johannesburg is considered one of the world’s largest urban forests, with more than 10 million trees. The polyphagous shothole borer, or Euwallacea fornicatus, seems to be a newcomer to South Africa. It was discovered in the country for the first time in 2017 by Dr Trudy Paap, a postdoctoral fellow at a biotechnology institute at the University of Pretoria. During a survey for diseases in the KwaZulu-Natal Botanical Gardens in Pietermaritzburg, Paap found a lane of infested plane trees. The identity of the beetle was subsequently confirmed and the tiny beetle – they are each about 2mm long – has been found at work in gardens and roadsides in Johannesburg, about 500 km from Pietermaritzburg. The beetle isn’t alone. It carries several fungal species with it when it infests living trees. One of these, Fusarium euwallacea, seems to be a permanent associate of the beetle. This fungus can eventually kill a beetle-infested tree. The beetle and the fungus have devastated trees in California in the US as well as in Israel. Insecticides aren’t effective because the beetles bore deep into the wood. The only known method of managing the spread is to cut down infested trees and burn...

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Eco Film Fest Review: Plastic, plastic, everywhere – and not a drop to drink

Eco Film Fest Review: Plastic, plastic, everywhere – and not a drop to drink

Our May meeting will focus on the problems with plastics, how it affects the oceans and our health. Sue Swain from Biowise will highlight the plight of wildlife in our oceans,  and she will also create awareness how to recycle plastics. Below an article highlighting the problems of plastics. LIFE, ETC MARELISE VAN DER MERWE LIFE, ETC 28 MAR 2018 (SOUTH AFRICA) Journalist Craig Leeson was planning to film blue whales when he instead encountered a soupy mess of microplastics in the deep sea. What followed was the documentary A Plastic Ocean, screened at this year’s Eco Film Festival. By MARELISE VAN DER MERWE. In the same week that Australia announced a pending ban on plastic bags, Indian media reported that the Maharashtra government had imposed a ban on plastic carry bags and thermocol cutlery – the 18th state in the country to impose a similar ban. Meanwhile Health-e News has reported on the dangers of microplastics in water, saying “microplastic is everywhere – from the fish to our water supply”. Enter the documentary A Plastic Ocean. It began when Australian journalist Craig Leeson was on the lookout for blue whales. Except he didn’t find majestic creatures frolicking in pristine waters. Instead, he found a polluted soup of degrading plastics. So he and free diver/ environmental activist Tanya Streeter began investigating the extent of the problem, and what they found wasn’t pretty. “How do we call something disposable,” asks Streeter, “when it’s indestructible?” Exhibit A: a brutus whale dying slowly on a beach. When it finally breathes its last, six square metres of plastic sheeting are found in its stomach. Verdict: it couldn’t eat and slowly starved, dying a drawn-out, agonising death. Exhibit B: A sea bird is found desperately ill, one of many. After it dies, 234 shards of plastic are recovered from its stomach. This is not a record. Previously, 276 shards have been pulled from the stomach of one 90-day-old chick. An estimated 90% of seabirds have swallowed plastic. Exhibit C: A turtle is found floating strangely on the ocean surface. It is found to have so much gas due to swallowing plastic bags that it is unable to dive for food. Exhibit D: Tuvalu, which has finally begun to fill in some of its unsightly borrow pits in the interim, is so covered in waste that residents have simply begun to build over it. But their living conditions are desperate. The subtext is clear: this could be the surface of the earth one day. The film does not only make the case for saving marine life. Many will be familiar with the so-called Great Pacific Garbage Patch; what A Plastic Ocean does is lay out in bite-size chunks what happens to the...

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