Massive die-offs in the Kruger National Park: This park is expecting massive die-offs of animals due to one of the worst droughts in history. According to research findings published by Navashni Govender, senior chief manager of conservation in the game park, this is not mainly as a result of too little drinking water, but because of a shortage of grazing. In the short term, the drought has caused a loss of biomass, while in the long term, encroachment of wood species and a decrease in animal populations can be expected. Trees, elephants and predators survive better with a water shortage but grass eaters suffer. Currently, only half of the game park’s vegetation is available for these animals. The available biomass (grass) is 66% less than in 1992. Under normal circumstances, 4 000kg biomass per hectare is required, but only about 399kg/ha is available. While predators survive a drought better because more weakened prey is available, there is a sharp decrease of animal populations such as buffalo, hippo and buck. The current drought is much worse than the previous most serious drought (1991-92), as this drought was preceded by a much drier year (2014), and, since July 2015, the temperature had been much higher than in 1991-92. Although it did rain in March and April, it was too late, as the growing season was over. The heat and low rainfall also caused a lower water level in many of the rivers. Although anmials must travel further to reach drinking water, sufficient surface water is still available. (Hanti Otto, Beeld, 10 June 2016).
Australian mangrove die-off blamed on climate change: Some 7 000 hectares or 9% of the mangroves in the Gulf of Carpentaria, in Australia’s remote north, perished in just one month according to researchers from Australia’s James Cook University, the first time such an event has been recorded. Norm Duke, a mangrove ecologist from this university, said climate change was the likely cause: “We are experiencing an unusually long dry season. Droughts are normal, but not so severe”. The dieback occurred synchronously across 700km in one month. Some of the mangroves suffering “dieback” were defoliated, meaning they were not yet dead but had lost all their leaves, and could recover. Most will, however, not recover. Local rangers told scientists they were seeing creatures like shellfish, which need the shade of the trees, dying, and that turtles and dugongs that are dependent on the ecosystem could be starving in a few months. By all accounts, the climate is going to become more erratic in future, and these types of events are expected to become more common. (News 24, 11 July 2016).
Pecan nut terms: Pecan nut trees are hermaphrodites (androgynous), which means that the male flowers (Afr blomkatjies) and female flowers can be found apart and in different positions on the same tree. There is a time difference among different pecan nut cultivars for pollen production, so that cross-pollination can take place. This process is called diagagomy. Pecan nut trees are also heterozygous, which means that seedlings are not replicas of the mother tree. In most cases, seeds or nuts that are then planted do not perform as the mother tree did. The concept ‘biological control’ is increasingly practised by pecan nut producers, because of the resistance of certain plagues to chemical agents, pollution of the environment, poison residues on products, the increasing cost of insecticides, as well as the withdrawal of certain insecticides from the agro-chemical industry. Insect predators that feed on aphids include, amongst others, Ladybirds (Coleoptera coccinellidae), Lacewings (Neuroptera chrysopidae) and Hoverflies (Diptera syrphidae). The advantages of the larvae of these predators are, however, not so well known to producers. As the larvae increase in size, they moult, and each moulting stage is called instars. The larvae play an important role in the agro-ecosystem and provide free ‘biological control’. (SA Pecan, vol 73, Summer 2016).
Value for your money: In spite of potato prices having skyrocketed recently, a recent study have found that potatoes are the best buy as far as price and nutritional value is concerned. Although dark green vegetables contain the highest nutritional value density, researchers have found that potatoes offer more nutritional value per cent. It is one of the cheapest options for four key nutritional substances, namely, potassium, fibre, vitamin C and magnesium. One medium sized potato (150g), with the skin, contains more potassium than a banana, provides nearly half of your daily dosage of vitamin C and contains no fat, sodium or cholesterol. Potatoes are nature’s legal performance booster. It is readily available, quick and easy to prepare, delicious and natural – an excellent source of carbohydrates. Except for the fact that it boosts performance, it can also assist with the recovery process after a race or strenuous exercise. If you need fuel for a big race, get some potatoes! Visit www.potato.co.za for more information. (Sources: Health24.com, Livescience.com, BBC.CO.UK)
Did you know? The word ‘potato’ comes from the Spanish name for the tuber – patata. This is a joining together of two South American names – batata (sweet potato) and papa (potato). About 5 000 potato varieties are grown around the world. (Source: ‘International Year of the potato 2008’, United Nations Food and Agricultural Organisation).