Even the dingo came with Aboriginal peoples who arrived from elsewhere; it may have caused the extinction of the Thylacine (Tasmanian Tiger) from the mainland, long before Europeans discovered it in Tasmania. (www.science.unsw.edu.au)
Mark Tronson knows that Australian scientists have been in the forefront of controlling familiar and more recent introduction of pest species, and he remembers the verses in Leviticus 25:23-24 "The land is mine and you are but aliens and my tenants. Throughout the country that you hold as a possession, you must provide for the redemption of the land."
Previous use of biological control of pest species
The most effective efforts in the control of foreign, invasive species have been 'biological controls'. Deliberate introduction of another animal or microbe or plant to keep the 'pest' in environmental balance like it has at 'home' can stop it from running amok. This methodology also reduces or eliminates the need for poisonous sprays.
Sometimes, these biological controls have been 'good' - the Cactoblastus moth controlled Prickly Pear; the myxoma virus still controls rabbits (and the recent introduction of calicivirus is effective in some areas); dung beetles bury animal droppings and reduce blowfly breeding; non-fertile fruit flies keep populations low ; and horticultural integrated management practices introduce a range of 'good bugs' that attack insect pests on valuable crops. (www.goodbugs.org.au)
Sometimes they have been 'bad' - the introduction of kookaburras from the eastern states to Western Australia (where they are not natural) in an attempt to kill snakes. But kookaburras hardly ever feed on snakes, and also they have become a real pest in WA, displacing some of the native birds. It is the snakes that are a natural part of the environment, keeping other potential pests at bay. They are no real threat to us.
Sometimes, the results have been downright 'ugly' – the infamous ugly cane toad that was introduced to eat a beetle that was a pest in the sugar cane fields. We all know the result. And it didn't even control the beetles.
A case study – control of salvinia water-fern
Scientists today improve their knowledge of biological control agents by carefully monitoring natural predators from the original home of the 'pests', and checking they do no unexpected damage, BEFORE they bring them here.
One dramatic example is the control of the Salvinia water-weed. Imported from Brazil in the 1950s as an aquarium plant, this water-fern forms dense mats over large bodies of water – particularly in tropical areas such as Queensland and Papua-New Guinea. After some unsuccessful trials with different insects, a weevil, Cyrtobagous salviniae, also from Brazil, was found to gradually but effectively control this weed in the tropics during the 1980s (photos below).
In 1985 Dr Mick Julien of CSIRO showed, after a 2-year trial, that this weevil could also survive the cold winters west of Sydney. The progeny of those weevils are still on that property, controlling the weed on two farm dams.
More recently, with the NSW Department of Primary Industry having taken over the project from CSIRO, there have been successful releases of weevils to control salvinia in the Hawkesbury area north-west of Sydney. Lesley Postle, formerly of DPI, has undertaken both fundamental research and practical monitoring of the process. She has also been educating local Government environmental officers about the value of biological control.
She says: "(The Cyrtobagous weevil) is of enormous benefit in the fight against this salvinia. The adults and larvae feed on the plant, but the most damage is caused by the larvae tunnelling within the stems of the plant. This kills the salvinia; it becomes water logged and sinks."
Our bugs now travel overseas
The expertise that Australian scientists have gained from research into biological control agents now has a reverse-twist. Dr Matthew Purcell of CSIRO has been working closely with scientists from the US Department of Agriculture to provide biological control agents from Australia, to control our own plants that have become a nuisance overseas in places like Florida.
He says this has helped us to learn about many more species of insects and micro-organisms than we ever thought existed, and understand how they help to control our own Australian environment. (www.csiro.au)
In an even further twist, Dr Purcell has sent some of the descendents of the 25-yr-old salvinia weevils to the USA, where, after extensive quarantine, their genetic make-up will be compared with similarly-aged populations from other parts of the world.
Science research is international, as was illustrated on the Science Show (ABC National Radio) on May 5th and previously mentioned by Mark Tronson. Australian scientists are up there with the best, using their knowledge to solve local and global environmental problems.
Moreover he says, this is line with Genesis 1 verse 28 that mankind has been given dominion (responsibility) over the created world.
Dr Mark Tronson is a Baptist minister (retired) who served as the Australian cricket team chaplain for 17 years (2000 ret) and established Life After Cricket in 2001. He was recognised by the Olympic Ministry Medal in 2009 presented by Carl Lewis Olympian of the Century. He has written 24 books, and enjoys writing. He is married to Delma, with four adult children and grand-children.
Mark Tronson's archive of articles can be viewed at www.pressserviceinternational.org/mark-tronson.html