Fire and its Effects on Wildlife

by Dan Carter, Redland Shire Council

Fire is a major part of the Australian environment. The sources have varied from lightning strikes, aboriginal burning to the present day fire management regimes. The flora of Australia throughout this long association has adapted features that allow some species to thrive or take advantage of the effects of fire to ensure better success. This could also be said for Australia's wildlife.

Obvious are the effects of high intensity fires (ie canopy fires) on populations through being burnt, loss of habitat and food source. Without bushland corridors or linkages the implications of such a fire can be devastating as recruitment of wildlife may not occur therefore effecting the wildlife diversity. This is a threat to our suburban bushlands if we do not provide an adequate system of corridors to facilitate the movement of Fauna during these times.

The following case examples show the importance of maintaining linkages between bushland areas. Fauna diversity and population levels will often not be able to re-establish giving feral species and/or other more aggressive and advantageous native species the opportunity to move in to the vacated habitat.

The effects of low to medium intensity fires on the wildlife can be advantageous to some species whilst being rather detrimental to others. A scientific study carried out by Peta Noris and Brian Conroy at two reserves (Yengo National Park and Parr State Recreation Area) found a moderate intensity fire left the site with no ground or leaf litter invertebrates after 3 months. When they returned after 6 months had passed there was a greater diversity of ground and leaf litter invertebrates then prior to the fire and this diversity was maintained after 12 months.

Bird populations were studied after the Victorian fires in 1983 in which a major wildfire that burnt out some 228,400ha of bushland that consisted of rainforest, heath and drier eucalypt forests. They found dramatic declines in bird population of 60% with this recovering in 3 years. Honey eaters and species that rely on the flowers of the area dramatically decreased after the fire while the insectivorous spp practically stayed at the same level (Loyn, 1999). It must be noted that the nectar feeding species were not killed by the fire but rather moved out of the area in search of food.

As these types of fires are less frequent within the Redland's it would be better to identify the effects of over frequent fires. The results of such fires and the effects on the wildlife may not be as obvious but the effect in the long term could be just as detrimental. Redland's wildfire season commences from September School holidays and tends to quiet down after the Easter holidays. Almost all of our fires are started with people playing with matches. A number of Councils conservation reserves have a fire regime of at least one per year.

This is concerning in relation to the Eucalypt regrowth that is killed in the following years. In reserves like R250 (Glider Reserve), Judy Holt Park, and McMillan Rd there are sections where there appears to be a lack of successive trees to replace the mature Eucalyptus trees which provide important habitat to the numerous species of fauna in these areas. The existing larger trees are also showing the signs of excessive fires with many of the trees having their bases being burnt out. This can weaken the tree and make it more susceptible to being blown over during high winds. The frequency of fires will also see slight changes in the flora of the area as species that can take advantage of the fire flourish. There are several flora species which are very useful in helping to identify areas which have been subjected to an excessive or too frequent fire regime. This is obvious at Birkdale Bushland where Molasses and Blady grasses are becoming dominant throughout the area. Other plants are useful for indicating areas that have not been burnt for a long time, eg Rainforest species. An experienced eye can quickly identify if fire is or has been an issue in your local bushland area.

Throughout the time that I have been fighting fires or doing prescribed burns I am constantly surprised by the resilience of our native wildlife and how they survive during and after a fire event. I had the privilege of watching a cockatoo use its wings to block off the entrance to its hollow by expanding its wings and reducing the volume of smoke entering its hollow. Skinks, frogs and wallabies can been seen scampering away from the fire. The bird life attracted to a fire is quite spectacular with many of the raptor species taking advantage of the animals running from the fire. Crows and magpies become prolific as they search through the burnt out area for any cooked morsel. Just recently after a fire at Pt Halloran Conservation reserve what I believe to have been White-throated Needle-tails which were picking off insects as they were flying out of a burning area.

At a recent fire management conference it was obvious that Queensland is a long way behind many of the other States who are starting to develop a good understanding of the effects of fire. There are still many questions to be asked about the effects of fire on our bushland environments in the Brisbane and Redland's region. What is the optimum burning regime for the different vegetation communities throughout the shire? Is the fauna diversity changing through the yearly burning of our reserves? How do we manage the bushland to reduce the effects of over frequent fires? How do we prioritise our actions if a fire will help species A but be detrimental to species B.

Anyone who lights a fire in bushland is deciding which species can and will be able to continue to survive in that immediate area.