Sunday 14 October 2012

Astonishing the Park-Keeper

So long as we regard a tree as an obvious thing, naturally and reasonably created for a giraffe to eat, we cannot properly wonder at it. It is when we consider it as a prodigious wave of the living soil sprawling up to the skies for no reason in particular that we take off our hats, to the astonishment of the park-keeper. – G.K. Chesterton

[Some gum nuts and blossoms of Western Australia] 
There is much Chestertonian astonishment to be had in Western Australia, particularly in spring. That such poor soils can send “sprawling up to the skies” such a variety and beauty of forms and flowers is truly astounding.

There’s a metaphor in there, to be sure. But leaving that and metaphysical matters to whisper from the wings, why should Western Australia’s flora be so astonishing? Isolation is one reason. Long ages of separation from other parts of Australia have given the flora of WA time and space to deal with the difficult climate and soil conditions in their own unique ways.

The age and relative stability of the land has helped too. The glaciation, tectonic movements and other earth shattering episodes of the east have largely left the west unscathed. For perhaps 250 million years the west has known the kind of stability that has allowed its plants to develop and adapt successfully to nutrient poor soils and often dry conditions.

The very richness of species – 13 000 and counting – adds its own competitive pressure. Species push to outdo each other in the race to attract the relatively low number of pollinators, be they birds, invertebrates or mammals.

[Spring in karri and marri forests, WA] 
Adaptable as it is, the west’s amazing flora is under threat from many quarters, most of them human in origin. Land clearing, salination, climate change and inappropriate fire regimes are all obvious and potent threats. A less visible but dire threat comes from a fungus-like pathogen called Phytophthora cinnamomi. Known in the west as dieback, or cinnamon fungus, it is spread in soil and through water and mud. It attacks the root systems of some species – and not others – causing death in susceptible species. In the west that’s 40% of all native species. Boots, camping gear, vehicle tyres and earth-moving equipment are some of its major means of spreading. Once established, it cannot be erradicated.

[Spring blooms in Western Australia]
As we drove through the south-west, two things were obvious. One was the incredible number of four wheel drives, seemingly more than 50% of all vehicles. While most were probably not genuine off-roaders, the potential for spreading die-back by that means alone looks frightening.

The other obvious thing was that we could not, at a glance, see the effects of dieback. But they are there: there in the displacement of the susceptible species by other species; there in the slow disappearence of susceptible species; there in the slow spread of dieback from infected areas to uninfected areas.

[More spring blooms in Western Australia] 
Thankfully we can do something to keep the threat to a minimum, bearing in mind that dieback is a menace in many parts of Australia. We can become hygience conscious with our boots, our vehicles, and our camping equipment. And we can be aware of when we are moving into or out of a dieback infected area. That way we can maintain the park-keeper’s – and our own – astonishment at these wonderful, free floral gifts.

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