The burning of bushland by Aboriginal people probably diminished the size of rainforest patches. When the first European settlers arrived, rainforests were largely restricted to many small refuges where favourable conditions existed. Isolated patches occurred from Tasmania, through southern and eastern Victoria, eastern New South Wales and Queensland, and across northern Australia to the Kimberley region.
During the past two centuries, many rainforests have been destroyed or modified, yet within them is found a large proportion of the country’s plants, animals and fungi. Some species have become rare or extinct.
All rainforests in Australia, including the small remnants, are of great value to science. From a purely economic viewpoint, there is unknown potential for life-saving medicines and other valuable resources.
A large proportion of the Robertson Rainforest has been removed since the 1860s, when land was being taken up and cleared for farming. Few remnants retain the floristic or structural integrity of the original rainforest. This is not to say that regrowth areas are not valuable; in the majority of cases this is all we have left. Stands of this rainforest in near-original condition occur in the Robertson Nature Reserve, Budderoo National Park at Knights Hill and in a few places on privately owned land.
There has been an increase in interest in rainforests in Australia recently, but much remains to be learned. The Robertson Rainforest is no exception; detailed studies of its nature are yet to be completed. Only a few sites are adequately protected and some species are inadequately conserved such as Pinkwood. The original forests were far from uniform. More of the remnants should become reserves or placed under covenants to ensure that they survive for future study.
The Robertson Rainforest is home to native animals that depend on it for food and shelter. There is much more to learn about invertebrates, other small rainforest animals and fungi. It would be unfortunate if extinctions occurred as a result of neglect or bad management.
Soil erosion is a problem on steep land during heavy rains. Not only is soil lost, but dams are affected. The Nepean Dam is largely supplied from Robertson and it has lately suffered from siltation. Increasing tree cover is a possible remedy. The fate of the Yarrawa Brush rests largely in the hands of Commonwealth, State and Local Government agencies, through funding and incentive schemes in partnership with private landholders and the community. If you have Robertson Rainforest on your land, contact your local council or the Robertson Environment Protection Society to find out how you can help save this critically endangered vegetation community.
Rainforest and fire
Rainforests are moist or wet vegetation communities that rarely get burnt by fire. It is not surprising to learn that rainforests do not cope well with fire. If fire burns a rainforest too frequently or too severely such a fire regime will most likely change the plant species composition to one that favours sclerophyll plant species, which cope better with fire. Thus, the sclerophyll species will “invade” and take over, outcompeting the rainforest species. Robertson Rainforest is no exception and is very sensitive to fire, particularly wildfire (unplanned burning), fire hazard reduction (planned burning) or pile burning. It can take many years or even many decades for the rainforest to recover from just one fire and the vegetation community could be permanently changed by just one hot wildfire. As a result, fire of any kind, particularly wildfire, is regarded as a “key threatening process” to rainforests and the animals that live in these plant communities. Excluding fire from Robertson Rainforest patches should be a priority. Fire is not the only threatening process to Robertson Rainforest patches; clearing, grazing, trampling, “under scrubbing”, weed invasion and feral animals are other threatening processes. Inappropriate application of fire can exacerbate these impacts and threats. Climate change poses a long-term threat to Robertson Rainforest by changing the amount and timing of rainfall, especially increased periods of very low rainfall. Wind, storms and increased temperatures can also change the vegetation composition of rainforest communities.