The 17th Wimmera Biodiversity Seminar was held on Thursday the 4th of September in Pomonal. This year’s theme was “Fired Up” – looking at all things to do with fire and biodiversity in our landscape. Quite a few of local FOGG members were able to attend and it was a really excellent day. Unfortunately we do not have space to do justice to all the speakers had to offer.
Speakers this year included:
Bill Gammage – adjunct professor at the Australian National University (ANU) and author of The Biggest Estate on Earth: How Aborigines made Australia. The book describes how Aboriginal Australians were actively using fire to cultivate the Australian landscape prior to European settlement. Bill expanded on his further research and learning, discussing the importance of the totem bond between people and animals, the fact that there were so many different words for “fire” – a different word for each stage of a fire and recovery, and different words for different kinds of fires. He described the burning practices as “planned, precise, local, universal, predictable and frequent.” Fire was an ally, “a scalpel rather than a sword.” “You see the fire in your mind before you light it – where it will go, where and when it will end”.
It was a hard act to follow but Dave Roberts our Grampians Ranger in Charge came next. He spoke of the challenge of balancing the risk to communities and the protection of landscapes, noting that we live in an environment much changed from that of 1778, with memories of Black Saturday and the impacts of climate change. He described the experiments with winter small patch burning in the Wannon area.
Darcy Prior of DEPI introduced us to the Phoenix Fire behaviour computer simulation model which is being developed to assist in predicting where and when a fire will spread.
Next Alan York who leads the Fire and Biodiversity Research Program within the Department of Forest and Ecosystem Science at the University of Melbourne. His research group investigates the interactions between fire, landscape pattern and biodiversity. Alan talked about the research into fire in the buloke forests which support the endangered red-tailed black cockatoos. In order to evaluate the balance between targeting the needs of this iconic bird and the needs of the rest of the plants and animals in the area his team focused on the insects there, in particular the ants, which are so important to the plants (their nests in the soil, their diet of leaves and seeds, their role in fertilisation). They collected 23,000 individual ants from 68 species! Their conclusion was that the needs of plants, insects, small mammals, and birds vary quite widely, but that the focus on this particular bird is not adversely affecting the rest of the environment in this location, but it could well in others. In the forest studied the best balance would appear to be 45% between 11 and 34 years between fires, 18% younger than this, 22% old to very old.
Natasha Schedvin of DEPI next spoke on research by La Trobe and Deakin Universities into fire in the Mallee, looking at the 5% target; the last four years of burning has burnt as much as in the previous 20 yrs. The Mallee was selected because of its biodiversity values and the readily flammable nature of the vegetation leading to typically high intensity fires – thereby presenting considerable risk to species if inappropriate fire regimes are applied. Similarly to the Buloke study they found that different elements (birds, insects, plants) have different fire regime requirements. They also looked at rainfall records to compare wet and dry years, Translating research into action plans for management is difficult but they think that looking at growth stages of plants is probably the best general method of deciding on burns.
Kristin Campbell of Deakin University spoke on her research into small mammal recovery post-fire in a time of climatic extremes. Her study surveyed 36 sites in the park over the last seven years. So three large fire events and one massive rain event. The trapping figures (13 species caught) showed just what a boom and bust cycle small mammals have. There were dramatic shifts in species composition and numbers over the years. Time since fire, prior productivity and rainfall are such important factors. This is why it is so essential to have longitudinal studies. She highlighted the importance of refuge areas especially sheltered damp places for recovery, which is important in a time of climate change.
Samantha Barron of Federation University spoke on her research into Sallow wattle. (I hadn’t realised before that it is a worldwide threat to ecosystems). She looked at sallow wattle in differing densities: from none to low, medium, heavy, collecting soil, looking at seedling emergence, collecting and sorting seeds in the soil. Sallow wattle follows creek lines mainly, it produces a huge seedbank, changes the ecosystem creating a positive feedback for itself, thus perpetuating the invasion process. The greater the infestation, the greater the impact on other vegetation. It was hard to assess what effect it has on the seedbank in the soil of other species. There’s a definite need for more research.
After all those speakers it was time to go out and look at the Park with Dave Handscombe. He showed us where the fire was particularly hot, where the back burns had been during the fire fighting, and where a recent planned burn had not stopped the fire, but had provided a less damaged patch. We also looked at an area of long unburnt forest which is where the newly discovered squirrel gliders were found. Plus he took us to an area covered in young sallow wattle seedlings.