What impact have Europeans had on the Australian environment?
Australia has been settled now for over 200 years, during which time the environment has changed in many ways, particularly its flora and fauna. There are of course many reasons for this, but a major one, and one rarely mentioned, is fire management, or at least indigenous fire management.
Most people think a fire is a fire is a fire, full stop, but this is not the case, as I hope to illustrate. Europeans use fire very differently from Indigenous People, their entire attitude toward it is different. In fact, as different as their cultures.
Europeans are sedentary farmers, they use fire to clear land and reduce the danger of being burnt out. Native vegetation to most farmers (even today) is a damn nuisance, something you have to clear before you can sow a crop or graze livestock and so make an income.
Now compare the above with the Australian Aborigine; they were nomadic and hunter-gatherers. Some people say they burnt the land to open it up and to provide green pick for kangaroos and other game. However, this is a very simplistic European view! Where there was a need to burn (not everywhere in Australia was traditionally burnt), aborigines were 'looking after country.' They knew that without a periodic burn, their country would die and so would they!
Aborigines were the original ecologists; they understood the value of various flora and fauna and the interdependency of one upon another. They understood that many plant species need a fire to clear the larger dominant vegetation and permit smaller plants and the animals that existed upon them to have their day. By contrast, today with little to no burning, many of these small species are becoming extremely rare and their pollinators gradually going extinct.
In my surveys, I have encountered plant species presumed extinct (not seen for over 50 years), occurring in their millions a season after a bushfire has passed through. The landscape had been transformed once the dominating larger species had been temporarily removed (they regenerate from rootstock and/or seed, but this takes a few years before they can again dominate the environment) and replaced by a completely new suite of plants
This enrichment of the environment provided the aborigines with a more diverse range of food in both flora and fauna, plus it encouraged the growth of medicinal and narcotic plants. It also provided improved habitat for kangaroos and opened up the country for them, but these were only part of the equation, not all by a very long way. It was as I have said, 'looking after country.'
So straight away it can be seen there is a very different attitude towards native species. For one a damn nuisance and the other their livelihood and prosperity.
Different types of Fire Management
European
Both these photos were of an uncontrolled bushfire in an area that had not been burnt for over 30 years. Fuel loads were excessively high and the flames fanned by strong winds.
Europeans even today, want the bush to do its own thing with minimum input from them. So what is common practice regarding fire management, the answer; nothing! You just leave it be, with the result the smaller species are replaced by the larger, which in turn mature and gradually die. There is very little new growth and what there is, is usually rank and worthless for wildlife. The vigour and vitality of larger plant species is reduced to the tips of branches, providing sustenance for only a few birds and insects. The diversity is consequently greatly reduced of both flora and fauna and this remnant of native vegetation is now only good for providing a hiding place for a few hardy species.
So you now have a largely unproductive area, where fuel loads are excessively high and just waiting for a spark. Whether that spark comes from lightning, campfire or a controlled burn, the outcome is usually the same. Total burnout! Excessive fuel loads mean the fire will be large and hot, this will often kill any large trees within the fire zone. It also means the regrowth is mostly the same age, but thanks to the seedbank contained in the soil, it will initially produce most of the vegetation indigenous to that area, however because of the time lapse between flowerings, the insects, mammals and other animals necessary for pollination and reproduction are often no longer there.
The animals that do survive the intense heat of these fires, are then faced by the lack of food in the aftermath, therefore the most likely survivors are those that could out-fly the flames, out-run the flames, or find a deep hole in which to crawl and hope the fire did not draw out all the oxygen. Consequently, these intense fires are devastating for the wildlife, with few survivors.
The aftermath of the fire, not a green leaf remained and even the sandy soil baked hard.
The fire that burnt these Grasstrees was so hot and prolonged, that the resin which binds the trunk together melted and flowed freely.
So with European Fire Management, there is a gradual downward spiral of biodiversity, first the fauna from lack of access to the vegetation they need, and secondly, diminishing flora, as species are no longer pollinated and consequently produce little or no seed and perish after gradually exhausting the soil seedbank.
Aboriginal Fire Management
Most aboriginal clans set aside a period each year for the purpose of 'looking after country.' These periods (around 4-6 weeks) are named and as such mean more to the people than something they ought to do. But something they must do! It was part of their spiritual and cultural lives. This fire season period differed between peoples and was dependent on factors such as vegetation type and naturally occurring climatic conditions that would aid fire control and/or successful regeneration. In central Australia (Spinifex country), burning was a more casual affair and would take place throughout the year and often used to signal other groups. However most burning off was done in anticipation of rain.
In rainforest areas there was no organised burning activity, for a start there was little need because dead vegetation would soon be recycled by micro-organisms in the damp humid environment, therefore there was less of a problem from high combustible fuel loads. These naturally damp conditions and the less combustible plants in rainforests would also reduce and extinguish fire. However, neighbouring areas of savanna, dry woodland and heath would have been burnt by indigenous people and in the prescribed manner.
So what is different? Simply everything! Let us take an area of fire prone bushland. The European would burn it all in one go, leaving it to revegetate as a largely single aged ecosystem. Then after say 20 or so years, the local fire brigade (may) burn it again, creating yet another single aged flora cover.
The aborigine faced with the same bushland in the same condition would through necessity also burn it and due to high fuel loads, it too would burn completely. But methods change from there on. The following year they would return to burn more of it, but unless there was dry annual grass, nothing would! But in the second year after the fire, patches would burn, these would mainly be short-lived plant species that have died, dried out and become easily combustible, however their fires would be small and not travel far. Bear in mind the aborigine used fire sticks to light their fires, not the European mixture of Kerosene and Methylated Spirits that literally drip fire. So their method in comparison was less efficient and getting plants to ignite and to stay alight would have been more difficult and consequently this too would aid the gradual development of burnt and unburnt vegetation.
In the third year there would much more vegetation that would ignite and the flames would slowly run. These fires travel slowly on a light breeze, but seldom spread sideways unless a pocket of more inflammable material is encountered, so the area of bushland begins to be broken up into interconnecting strips of burnt vegetation and many islands of unburnt vegetation.
The fourth year the vegetation will burn even more strongly, but it is stopped by the interconnecting strips of vegetation that was burnt in the previous two years. At this stage, the areas of burnt, partially burnt and regenerating vegetation is becoming quite complex and unless the aborigines went to a great deal of trouble and visited every unburnt island, the larger area would now not burn. So in the fifth year some pockets of 5 year old vegetation, plus bits of other neighbouring aged will also be burnt, but still many islands, both large and small remain where slower growing plant species can grow to maturity, flower, seed and reproduce.
So a highly complex web of different aged vegetation begins working together, not only to protect themselves against bushfire, but also permitting all plant species to exploit their different requirement. This in turn will attract a greater diversity of animals, who can also seek protection from predators in the denser unburnt sections, plus have a good chance of escaping any fires.
The big difference is not in High-Tech equipment, nor in the planning, but it is in the dedication of a regular fire management practice, plus an interest in the long-term health of the ecosystem. The thing I think is of greatest interest, is with this simple annual fire-stick practice, the system becomes increasingly easier to control and manage. The danger of wildfire is greatly reduced, but biodiversity is greatly increased. If we are inclined, we can still learn from the aborigine of how to manage this land, because they did have a win, win situation when looking after country!
These orchids are examples of small plants that are advantaged by Aboriginal Fire Management.
I have through necessity had to simplify this post, with the consequence that many factors have been omitted. So if anyone has questions, please ask in the comments section below and I shall try to answer them.
Quacking Frog, Crinia georgiana
