Fire and managing the damage

back burn

Nurturing Fire

Bushfire may be the most extreme ecological change we can witness, it is destructive,  it is inevitable, and it is necessary. Fire is essential to the ecology of most plant communities in the Royal National Park. Our flora is largely adapted to fire with strategies to regrow and reproduce after a fire event. Many plants depend on this fire response to complete the life cycle. Some marsupial reproduction may also be geared to take advantage of the green pick that flourishes after fire. In past millennia under aboriginal care there have been seasonal fires lit with the purpose of increasing accessibility and the productivity of the country. There is good reason to assume that our notion of an ideal natural environment should include more fire, but there are limits:

Damaging Fires

  1. Too hot. Fire that escapes into the canopy of the trees will kill a range of plants and the animals that take refuge in treetops. When the landscape is renewed there will be a suite of plant and animal species missing, diversity will suffer.
  2. Too extensive. Fire that is uncontrolled will burn longer and further, the sheer scale of destruction will produce additional destructive effects.  Where fires are controlled and restricted to a small scale there is a mosaic pattern of burnt and unburnt land, this allows for movement of animals between different areas and recolonisation after fire. Likewise, plant species that are burnt in smaller patches will be more likely to re-establish after fire. In a parcel of bushland surrounded by a cleared landscape there can be little re-colonisation from the surrounding area.
  3. Too frequent. The re-establishment of life after the fire takes time. Plants that regrow from seed take time to mature and set new seed, animals also take time to recolonise after the plant life rebounds. The fire alters the physical landscape too, soil and rocks are baked, beds of ash cover the hills and move into the creek beds, all this takes time to return to stasis.Curramoors fireCurra Moors 6hrs

Fire management

Controlled ecological burns do take place in the Royal under the National Park and Wildlife Services. These fires are infrequent and subject to limited staff numbers and equipment, by comparison the Rural Fire Service is well resourced. The RFS is given the responsibility to conduct hazard reduction burns to protect housing adjoining bushland. When fire in the park is out of control command is given over to the RFS and while the NPWS will continue to assist, the task of managing risk and taking  strategic decisions rest with the RFS. The priority of the RFS is to protect human life, of the public and of the firefighters, then to protect property. Risking life to protect the bush is perhaps a low priority. Putting out the fire is the objective and this should be done safely and as easily as possible. Ecological objectives are not forgotten but they are weighed up somewhere in the mix. There are a raft of issues that create a tension between good ecological management and effective fire control, remembering that poor fire control can lead to disastrous ecological outcomes:

  1. Back burning. One way to stop a fire is to remove fuel in its path. If there is sufficient time, and the wind feeding the fire is favourable, and if there is good access, it is then easy to set a line of controlled fire that will advance towards the oncoming wildfire. When the two fires meet they will subside having burnt everything on the fire ground. The back burn will usually  be set where there is vehicular access to allow for water tankers to protect the fire fighters and guard against the possibility that the back burn will itself go out of control. This strategy means that a large area of land may be burnt  between the back burn and the wildfire and fleeing wildlife will be trapped between the two fires. The back burn may be set on land that would not necessarily burn if left alone. Perhaps a gully with moist vegetation that would not necessarily set fire by normal ember attack, and this artificial fire will be burn with greater speed, uphill rather than down, again trapping escaping wildlife. Again the cost of doing nothing must be weighed against the cost of taking practical action. There may be alternative strategies, like proceeding into the bush away from the protection of the tankers, but this carries greater risk, again an exercise in balancing costs. backburn 2Lady Carrington drive
  2. Water. Another way to put out a fire is to douse it with water, if that water comes from the ocean it will contain salt that will stay in the soil and prevent plants from growing. The bare landscape will then be open to erosion and soil will be lost and watercourses will be choked with increased sediment. The tankers refill from fresh water sources, weirs and hydrants, but the choppers are able to scoop water from the beaches, and where the ocean is close it may save valuable flying time. saltwater scaring1An Erickson skycrane was filmed taking seawater from Garrie beach for the Curra Moors fire and there was some minority social media comment made about the damage to the environment. The public appetite seemed to be extinguish at any cost, but it was reassuring  that RFS Sutherland fire control were quick to post other clips and shots of choppers taking water from freshwater sources. Using saltwater is a known problem and should be an option of last resort. It may be that the RFS fire control is more open to ecological concerns than the general public. When it comes to the fear of fire the bush becomes an enemy and those who are concerned for the bush become caught in an ideological war where lives and houses are seen to trump all other concerns, no matter how distant the fire threat may be. chopper waterhole
  3. Fire retardant. The most expensive way to deal with fire is to use a chemical retardant. In this fire retardant was spread by use of a Very Large Air Tanker, a modified DC8, with a reputed cost of $40000 per drop of bright pink retardant. While not as damaging as salt water the retardant does contain high levels of ammonia which will alter the growing conditions for plants, especially in or near the waterways. Here are some extracts from an RFS factsheet on fire retardants:

    The NSW RFS drops fire suppressant retardants and gels such as Phos-Check®, Blazetamer and Thermo-Gel from aircraft during firefighting operations to help slow the spread of a fire.

    Long-term fire suppressants such as retardants are essentially fertilisers (ammonium and diammonium sulphate and ammonium phosphate), with thickeners (guar gum) and corrosion inhibitors (for aircraft safety).

    Sometimes a red coloured pigment, made from iron oxide, is added so that those spraying can see where they have released the fire retardant. Examples are Phos-Chek MVP-fx and Phos-Chek 259-F.

    Short-term fire suppressant foams are made of a combination of wetting agents and foaming chemicals, mixed with water. This allows the water to penetrate surfaces more easily. Their usefulness is limited against high-intensity fires, where long-term retardants have proven more successful. Examples are Angus ForExpan S, and Phos-Chek WD-881.

    retardentVLAT

  4. Containment. When the fire is surrounded by burnt out land the fire will subside and eventually die out. After the flames die there will be trees and logs that continue to smoulder and gusty winds can restart new fires.  This protracted period of danger can be shortened if all land within the containment lines is burnt out quickly. The burning can be accelerated by the use of aerial incendiaries. This need to bring the fire to a quick end may run counter to good ecological management, it may be better if the fire ground retained patchy areas of burnt and unburnt vegetation.

Clean Up. After the fire there is further work to be done that may have environmental consequences. Burnt trees are sometimes unstable and may represent a risk to the public if they were to fall on the roadway; black tree, black road – an accident waiting to happen. These burnt trees also have habitat value for wildlife, many birds, bats and possums nest or roost inside the shelter created by the sculpting effect of fire. Many species are entirely dependent on these hollows to reproduce. It would be good if tree felling after the fire was sensitive to these ecological values.

Contaminants will arise from the destruction of infrastructure. There was a time when all the “hardware” in the park was made of timber or steel, but now the use of plastics has gained a foothold. Roadside markers are now made of plastic and these wilt in the radiant heat, but more worrying are the kilometres of fibreglass footpaths that turn into fine filaments that will remain as permanent detritus in the park. The walk to Wedding Cake rock was unaffected by this fire but the section of new track north of Garrie beach has been burnt out. Clean up will involve careful raking and removal of all affected topsoil.

walkway

 

Deer

deer elvis

Meet Elvis the deer in his prime, antlers aloft, coat shiny and sleek. This photo was taken back in the winter breeding season when good looks are important. In the heat of summer the antlers have been shed and the fur is looking mangy. Deer herds are now congregating under the shade of safe houses where they have easy access to water and a daily feed of vegetable scraps and treats. Older males and younger bucks seem to get along at this time of year. When the sun goes down the deer are up and about trimming the grassy lawns down to a perfect stubble. The urban deer will take refuge in the bush if they are threatened, but it seems they have reached an arrangement in Maianbar of live and let live. Of course they are an ecological nightmare, but that’s another story.

jingle bells

Red Flag

Trigger warning, a few pictures of a dead animal follow, also some material of a sexual nature, but be assured no cruelty or misadventure is indicated.

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Out on my daily walk I came across a little dead mammal on a bush track. Strange. Dead animals are not usually left animals alone for long making a handy meal for the many scavengers of the bush; rats, monitors, owls, foxes. I bent down and had a sniff, it smelt a little, maybe it and been dead for a day or two. The eyes were receding. I noticed it had a pointy snout and little serrated teeth like a steak knife. It was an Antichinus, a small carnivorous marsupial “mouse”. I took a couple of photos in the fading light and wandered on thinking about how and why the animal came to be lying there. Dead as a doornail.

For the sake of comparison here below are two skulls, a Brown Antechinus (a) on the left and a mouse on the right (b). Notice the large protruding incisors of the rodent compared to the long row of teeth in the antechinus. Note also the pointed arrangement of toes on the feet of the antechinus and the toes of the antechinus are separated while they are fused in the mouse.

Skulls

Some way down the track I stopped and turned back to check for testicles. Sure enough, bold as brass, a huge scrotal sac, indicating a dead male antechinus. The cause of death now obvious, over-exertion during breeding season. Facts furnished here by the Australian Museum “Males live for approximately 11 months and have a short breeding cycle of about 2 weeks in winter, after which they die as a result of stress and exhaustion. Females give birth to undeveloped naked young that latch onto teats in the pouch for up to 50 days. The pouch is an open slit found on the belly.”

Brown antechinus fact sheet

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Going out on a limb

In identifying a plant one is often making a guess. An educated guess is still a guess and sometimes there is no correct answer. Many of the banksias belong to groups known as complexes. Members of the complex are seen as separate species but they can also hybridise – meaning that they may have intermediate forms. Any one plant may have a variety of different features, sometimes typical, sometimes weirdly different. Sometimes the scientific name serves to obscure the identity of a plant, take Banksia oblogifolia, it is supposed to have oblong shaped leaves, where the tip is blunt and the base of the leaf is relatively broad. As it happens the leaf shape is variable, and the most reliable identifying feature is a rusty coloured felt that covers the midrib and young branches. The scientific name may endure even if it is misleading because the history of the name is seen as important. The type specimens of banksia oblongifolia may have had particularly oblong leaves, but specimens from further afield may not fit in the box.

banksia oblongifolia

Bus Stop banksias

Behind the artfully decorated Maianbar bus stop there are half a dozen species of banksia within a short walk. To identify them it is handy to learn their names. The information within the name will jog the memory each time you try to identify a plant. Plants may have a common name and a scientific name, both names can be useful. The common name is least reliable, it will vary from place to place and can be pretty vague. The scientific name will slot the plant into the taxonomic hierarchy which will tell you much about the structure of the plant and how it relates to others. The scientific name can change when academics get busy, but it will lead back to the first scientific description of the plant. The scientific name is a double-barrelled binomial usually composed of latin or greek roots or a nod to a dignitary, explorer or a botanist. All of this is useful information.

In the photo below is Banksia spinulosa, the hairpin banksia. The old fashioned hairpin is now an uncommon object and so the common name is possibly not very useful. The generic name Banksia was conjured up in 1782 by Carl Linnaeus the younger, son of daddy Carl Linnaeus the swedish naturalist who invented the taxonomic system. The first half of the binomial honours Joseph Banks who collected the original type specimen in 1770 on Cooks “voyage of discovery”. The second part of the name refers to spines on the leaf tip.

 

Banksia spinulosa
Am liking the common name now that I see what an old fashioned hairpin from 1850 looks like. It has points on the end that would give you a little jab like little spines, whereas the modern bobby pin is not nearly so fearsome. But all jabbing aside the rounded end of either style of pin resembles the bent anthers of the rows of flowers.

 

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Bashing the big Banksias

Bansia ericafolia

May 15 2017
Tis the time of year when Banksia ericafolia is in full bloom. This shrub is common up on the heathland (the name erica refers to South African heath, which has a similar leaf shape). Other Banksias flower at different times providing honeyeaters with a reliable supply of food, but B, ericifolia is the most bountiful. Early settlers were shown how it was a source of bush tucker for aboriginal people. You can run your hand over the cone and lick off nectar or soak them in water for a sweet drink. So abundant is the nectar that you can see droplets glistening on the flowers and dripping from the branches, on the ground below there may be ants feeding. In the photo notice the damp patch at the base of the flower cone and droplets among the flowers.

 

Scientific literature (yawn…)

Unlike social media the scientific literature does not repay the urge for instant gratification, the gems are buried deep.

Scan this text and follow the final link for a series of scientific papers on the natural history of the Royal National Park.

“The Linnean Society was founded in 1788 by botanist Sir James Edward Smith. The society derives its name from the Swedish naturalist Carolus Linnaeus, the ‘father of taxonomy’, who systematised biological classification through his binomial nomenclature. He was known as Carl von Linné after his ennoblement, hence the spelling ‘Linnean’, rather than ‘Linnaean’. The society had a number of minor name variations before it gained its Royal Charter on 26 March 1802, when the name became fixed as “The Linnean Society of London”. In 1802, as a newly incorporated society, it comprised 228 fellows. It is the oldest extant natural history society in the world. Throughout its history the society has been a non-political and non-sectarian institution, existing solely for the furtherance of natural history” Gage A.T. and Stearn W.T. (1988) A Bicentenary History of the Linnean Society of London, Linnean Society of London, p. 148

The Linnean Society of NSW

FOUNDED 1874. INCORPORATED 1884. ‘NATURAL HISTORY IN ALL ITS BRANCHES.’

Natural History of the First National Park

A Symposium presented by the Linnean Society of NSW and National Parks & Wildlife Service was held in the Auditorium of the Visitor Centre, Kamay Botany Bay National Park 29 September – 1 October 2011.

For a list of talks and posters presented:

http://linneansocietynsw.org.au/symposia/First%20National%20Park/First_National_Park.html

For pdf files of the published proceedings:

https://openjournals.library.sydney.edu.au/index.php/LIN/issue/view/470

I can promise you maps and pictures of roadkill.