There is a world of difference between collecting seeds and salvaging them. Diana Corbyn, Lecturer in Conservation and Land Management at Challenge TAFE, enthralled us with her presentation on the power of seeds, at The Hub in Mundaring, in July 2007. Her simple illustrations and easy language helped us appreciate their variety from the simple to the complex and the wonders of plant reproduction.
From the fleshy fruits we love to eat to those with their hard, seed bearing cases (like Banksia) that we scarcely regard as “fruit”, Diana demonstrated how a seed is “a baby plant with a raincoat, a sandwich, and a very small drink of water”. It was fascinating to gently peel away the outside skin of a broad bean (its “raincoat”) and split it into two. You could clearly see the radicle that develops into the primary root and the cotyledon, which will develop with the plumule to bear the first leaves. Their power to grow is awesome when you regard them at such close quarters.
She showed us spores that drift on the wind; cones that let their seeds fly free like little helicopters when they sense smoke from a fire is sufficiently cool for the seeds to be safely released; seedpods that forcibly eject their genetic code in the natural process of reproduction. Diana held us spellbound while we learnt the difference between collecting seed (with the right license and not more than 20% from any plant) and salvaging seed, with permission for all seed to be collected if an area is to be cleared.
Eastern Hills (Mundaring Shire) has the best structures and outcomes from volunteers for bush and wetlands rehabilitation in Australia and the local schoolchildren are a regular part of those volunteer groups.
Teaching them to understand their local biodiversity also means ensuring they have the highest regard for protecting the bush against the spread of dieback. Preventing dieback is everyone’s responsibility. We can all do something to help reduce the spread of this devastating plant disease.
Dieback is not a natural part of our local bush. Phytophthora cinnomomi is a root-rotting fungus that was inadvertently brought to Australia sometime in the early stages of European settlement. It spread to native forests and woodlands and it causes ‘Dieback’. It spreads because the soil attaches to your car wheels, your horse’s hooves, your truck wheels, your four-wheel-drive wheels, your bike tyres and your shoes or when you take home plants, rocks or soil. Especially in wet weather. So far, it has been impossible to eradicate and prevention methods have been to close parts of the jarrah forest and wash down vehicles that may have been in infected areas. Everyone who travels in and out of dieback-infested areas must wash their cars, especially the wheels, and their shoes when they leave. This is especially important information for you, if you are a tourist.
Don’t bring plants, rocks and soil from the bush into your garden, because you could introduce dieback and it will kill your garden plants including roses, azaleas and fruit trees. From Eneabba to Cape Arid, east of Esperance, its arrival has had catastrophic consequences for the biota of a number of ecosystems. In small areas that are dieback-free, a chemical called phosphate that is not toxic to plants or animals can be applied to flora and vegetation by spraying or injection. This is done where there is risk of new infestation or to prevent the spread of an existing infestation.
Dr. Ralf Cord-Ruwisch (Murdoch) found that some different compost processes could completely inhibit the growth of phytophthora in the laboratory. The ORT biogas/compost system (patented as DiCom) produced a compost with very good inhibitory effect of the fungus. “There is therefore potential to create a biological dieback control agent from solid waste, as well as a renewable source of biogas,” he said. (2002)
In the field, in the mid eighties a resistance gene was identified when it was noticed that some jarrah trees were thriving while others around them were ravaged by dieback. More than twenty years of collaboration between Murdoch University, CALM, Alcoa and ECU allowed Associate Professor Jen McComb (Murdoch University) and Dr Ian Bennett (Murdoch University, now at Edith Cowan University) to develop techniques to clone and propagate the highly resistant plants. In July 2001, the dieback resistant seed orchard was planted at Manjimup.
Seeds collected from this orchard in 2006 grew into viable seedlings at Alcoa’s Marrinup Nursery. For the first time, these dieback resistant seedlings are on offer to local community landcare groups. On July 8th, 2007 Alcoa launched this programme and at that event, visitors learnt about the history of the Dieback Resistant Jarrah. They toured Alcoa’s Marrinup Nursery and the Dieback Resistant Jarrah seed orchard at Alcoa’s Huntly Mine and it was great fun to find out how local community landcare groups can become involved in this project in the future.
Helping to control the spread of dieback is the responsibility of all in the community and its negative impact on native vegetation cannot be understated.
