Across Gold Creek from my hide, where I have been monitoring a breeding Platypus in recent years, is a Sandpaper Fig. Its notable feature is that it is old, but apart from that it is just another tree arching over one of the two large ponds of the creek.
I have taken an interest in this tree because there are long periods of waiting between sightings of the platypus, but there are many similar trees overhanging the creek.
How it got to be growing just in this position could probably be because one of the figs from further upstream was washed down the creek and was deposited in a recess in this section of the creek many years ago.
I have no idea how old the tree is, but it has clearly seen better days as it has lost many branches and shows several signs of old age including severe termite attack. It would certainly have been around in the first half of the 20th century when this section of Gold Creek was the local swimming hole. It was probably around before the land was cleared and used as a dairy farm by the Dart brothers. I can imagine it existed when members of the Turrbal or Jagera aboriginal groups populated the area. Perhaps the aboriginal children snacked on its fruits before lollies were available from the Brookfield store.
Since the cattle went, Chinese Elms have invaded the cleared areas and the swimming hole is no longer used, but the creek banks have a good cover of Sandpaper Figs and Creek Lily Pillies and other natives, so this section of Gold Creek is in good condition and supports a wide range of wildlife.
The Sandpaper Fig has many decayed limbs, and one hole is the resting place of an elderly Northern Mountain Possum. He camps here during the day when he is visiting this part of his territory. The Sandpaper Fig is interconnected with other trees along the creek by several vines. When the possum wakes up in the evening, he climbs upwards and takes off on an aerial highway that covers much of the creek.
He is joined by many other inhabitants who also use this network. Young water dragons sleep along the thinner branches during the night where they are safe from cats and other predators.
If the Water Dragons sense danger, they just plop into the water and swim to safety.
Many birds frequent the fig’s canopy. Lewin’s Honeyeaters are always present – not for nectar, but insects which form much of their diet. Whipbirds are also common, and the fig produces fruit for a range of fruit eaters including Pale-headed Rosellas, Figbirds, Satin Bowerbirds and Rose-crowned Fruit-doves. Brush Turkeys and Noisy Pittas feed on the figs that fall on the banks of the creek. Striated Pardalotes use the fig as a staging post as they excavate their many holes in the bank of the creek where they raise their young. One parent will wait impatiently in the tree with an insect in its beak while calling incessantly until the other parent leaves the hole and it is their turn to feed the hungry young.
Most of the figs fall into the water and there is always a team of Eel-tailed Catfish waiting below.
As well as fruit the Sandpaper Fig drops a considerable number of leaves throughout the year. These rot down in the water and start a food chain involving bacteria and fungi, which are eaten by worms and aquatic insects such as dragonfly, mayfly and midge larvae, which are then eaten by fish and platypus.
The creek is usually ankle deep in mulm derived from the leaves and fruit and the platypus’s bill with its electrified sensors is ideally adapted to sifting out the insects and worms contained in the debris.
When the creek floods the mulm is washed away and a new cycle develops where the whole process speeds up with the input of minerals and light. Floods undercut the banks developing suitable dens for the platypus and water rats. Here too, roots of the Sandpaper fig stabilise the bank. The underground extent of the fig is just as large as the aboveground branches and trunk and the fig produces two distinct types of roots. The structural roots support the trunk and branches and take up water. The fine roots collect the nutrients to feed the growth.
The trees along the creek are essential for the health of the creek and support an amazing amount of wildlife. Clearing to the edge of the creek destroys this habitat and leads to a breakdown of the ecology of our waterways. The work of the MCCG environmental restoration groups in revegetating our waterways is vital to maintaining Moggill and Gold Creeks in a condition that is as close to pristine as any waterway in Brisbane.
The Sandpaper Fig was snapped off by the recent flood and washed downstream to the bridge at the junction of Adavale St. and Savages Rd. The Mountain Possum hole survived but it is very exposed, and it is doubtful it will be used again. A few young branches remain but the main trunk was severed about 2 metres above the ground. The entire root system survived and held the bank well so the old tree will rise again, but it will be many years before it plays its part in supporting the animals with food and the aerial highway above the creek. In the meantime, other young trees will take advantage of the extra light and take the old fig’s place in the canopy above Gold Creek.
Words and photos by Ed Frazer