Keeper of the Secret Stars

[the beautiful star-shaped flower of the sassafras tree]

[More invertebrate surprises from the Tasmanian forests]

Flowers are supposed to be obvious. After all their job is to attract pollinating insects or birds, a story as old as the birds and the bees. But sometimes the show is less about being showy, and more about being smelly.

In the case of the sassafras tree (Atherosperma moschatum), smelly is an unkind and inaccurate adjective. Find yourself among sassafras at the right time, say early spring in Tasmania’s wet forests, and you may be treated to a feast of fragrance.

The first time I caught the scent I had no clue as to its origin. It took an old time bushie to point out the source of the rich scent that had my head reeling. Sassafras flowers are found on the underside of branchlets and are often hidden by the leaves. Or at least until they fall, and spread a carpet of beautiful creamy-white, star-shaped flowers that light up the forest floor like a night sky.

Sassafras trees, which are found in rainforest from Queensland through to Tasmania, have another secret. They have an intricate and intimate relationship with a butterfly, to name names the Macleay’s swallowtail (Graphium macleayanum).

This member of the Papillon family – the only one found in Tasmania – has stunning green, black and white markings, and two distinctive black “swallow-tails” at the base of its wings. Its flight is jittery and jagged, its wings ceaseless except when briefly stopping to sip nectar. The female lays its eggs on the underside of sassafras leaves, which the resulting green, hump-backed caterpillars then eat. When the larvae pupate, the pupae are often suspended beneath the same sassafras leaves.

The close and cosy relationship turns full-circle when the butterflies emerge and feed on the nectar of the sassafras flowers. They pollinate the trees in the process, paying back their hosts for bed and board, and ensuring that the secret stars will again fall from the forest in the coming spring.

Ecosystems Unaware

[Spot the difference: a Pencil Pine needle and pencil pine moth larva - photo courtesy Tim Dyer]

[Sometimes ideas just drop into your lap!]

Most of us, I think, are gormless when it comes to noticing species other than our own. Occasionally we may swat a fly, pat a cat, spot a bird or catch a fish. But take us into the bush, or even into our backyard, and ask us to describe the lives of the creatures that share those spaces with us, and our tongues will fall flat and still.

After spending some time among pencil pines this summer, I decided to read up on these marvellous Tasmanian conifers. I have written a little about them here http://auntyscuttle.blogspot.com/2010/01/walking-with-ada-2-great-pine-tears.html

But as wonderful as the species itself is – especially en masse – my ignorance of its broader place in montaine ecosystems was demonstrated by something that literally dropped into my lap. After a sweltering day climbing to a remote campsite high above the Overland Track, I was enjoying the shade of a pencil pine tree when a small green pine needle fell onto me.

And then the “needle” curled itself and raised its head! It was a caterpillar. It bore an uncanny resemblance to the articulated, overlapping platelets of a pencil pine needle. This appearance is both a protection and a convenience, as the larva of the pencil pine moth (Dirce aesiodora) feeds exclusively on the needles it so closely resembles.

Even when it metamorphoses into moth form, it will still spend most of its life in and around pencil pines. Found at altitudes of 1000m and above, the pencil pine moth must shelter from some of Tasmania’s wildest and wettest weather. Where better than in the pine groves that are so well adapted to these conditions?

Both the tree Athrotaxis cupressoides and the moth Dirce aesiodora have been surviving such weather for a very long time. In fact both have lineages dating back to Gondwana. In a kinder world we might doff our hats in respect to these ancient wonders.

And that is just one moth species, associated with one tree species, in one small altitudinal band of one small island. To scratch the surface of our ecosystem ignorance is to uncover another multitude of questions. But how vital that we keep asking those questions, rather than dying in ignorance – and taking whole ecosystems down with us.

Back Again For the First Time

[Sun & moonrise over Mt Pelion East, Tasmania]

[Reflecting on a recent bushwalk in Tasmania's Pelion Range]

About 20 years ago I spent a week in the Pelions, a range of mountains that variously glowers, sparkles or hides itself above the centre of Tasmania’s Overland Track. In Mt Ossa (1617m) the range contains Tassie’s highest mountain, while Pelion West ranks 3rd, Thetis 13th and Pelion East 17th. It really feels like the roof of this rugged and rumpled island state.

This February I returned for another dose. For some of our party this raised some interesting philosophical questions. Is going back always a lesser experience than breaking new ground? Isn’t it “better” to see new places and find new paths?

We always seem to discuss this when trying to decide on walking destinations. On this one I tend to side with Heraclitus, who was supposed to have said

No man ever steps in the same river twice, for it is not the same river and he is not the same man.

On my first trip here, I was in my 30s. My memory of the week was that we climbed everything in sight, and that it was more exhilarating than exhausting. But don’t trust my memory as far as you can throw it! Less than a week after returning from the latest walk to the same area, exhilaration is again winning the arm wrestle with pain.

The photos don’t help. They neatly remove the aches, heat, sweat, leeches, march flies and mosquitoes from the scene. But then they also remove the bird calls; the humorous banter; the taste of the food; the magic of clean drinking water; the rasp of the rock; the whisper of the wind; and the sheer quiet calm of the evenings.

Alright – yes! It was a brilliant return to the Thetis Saddle. And as the pain falls away the joy remains firmly seated.

It makes me somewhat glad of the limitations of memory, even of the limitations of the human condition full stop. Had I recalled the agonies of the earlier walk, would I have returned equipped with my older, dodgier joints? Or more broadly would I really want to know the future? Even the trivial near-future, like how knackered I will feel after climbing steeply through scrub for a few hours?

No, sometimes being tethered to time and subject to imperfect knowledge gets you further. Does that make me like the neuronally-challenged goldfish of urban legend? (As it swims around its circular bowl, every time it passes the same rock it exclaims: “ooh, what a nice rock”.) Perhaps … but overall I think I prefer going back again for the first time. Even if it is the same mountain range, after the last walk I am certainly not the same man!