Permanence is a temporary state on the coast. Despite having attained some reasonable geological age the Bluff is slowly retreating from a relentless ocean tide. And while the landscape appears green, indigenous plants are retreating from a relentless tide of weeds and Lake Murtnagurt is retreating from a relentless tide of development.

I really admire those creatures that regularly attempt to colonise the basalt shelves below the Bluff at 28W.When exposed, these platforms display a dreamtime antiquity, cleaved with sarcophagal eeriness and drenched with micro-algal slime. Tiny, tiny periwinkles, mussels and limpets begin to cluster in the scars, pocks and runnels of this ancient eroding rock. But with one violent shift in the weather the aspirations of another glorious mollusc civilisation is buried under several tonnes of impermanence only to reappear several lunar cycles late to start the whole process again.

The Environment Protection and Biodiversity Conservation (1999) is the legislative instrument that declares which noxious things are major environmental threats to be dealt with severely. To date the official list includes foxes, rabbits, goats, cats, cane toads, long-line fishing and even climate change. However it is disturbing to learn that not one foreign plant has managed to be listed under the act - not one weed. Apart from the four billion dollar annual cost to the economy, weeds insidiously take a permanent community and change it into something else.

Dr Rachel McFadyan, a woman outstanding in the field of weeds, recently told the 2007 Biodiversity Extinction Crisis Conference that; "We are up against a prevailing misinformed mindset that sees all green plants as essentially the same – as passive, friendly and just a part of nature." While nothing is forever the extinction of coastal vegetation would seem to be permanent. Somehow I prefer fairy orchids to freesias, clematis to bridal creeper and any of the 20 native grasses to couch grass.

National park rangers in Chile recently lost a lake. The unnamed 2 hectare lake isolated deep in the glacier riddled (and oddly named) Bernardo O’Higgins National Park in the south of Chile was there in March. But when rangers returned in June they discovered a 30 metre deep crater with a few chunks of ice in the bottom. According to disappearing lake experts, (yes disappearing lake experts!) one theory is seismic activity opened up a fissure that swallowed the lake. The theory that holds more water is that the unstable moraine holding the lake collapsed due to the influx of water as a result of rapid glacier melt. The lake wasn’t there 30 years ago either. It was merely the temporary creation of eons of glacial activity. If it wasn’t such a natural occurrence it may be deemed careless to lose a lake.

(Barnardo Higgins was the illegitimate son of an aristocratic Chilean daughter and an Irish engineer who went on to be a revolutionary, an exiled revolutionary, a returned revolutionary and finally the liberator and supreme director of Chile in 1817. His rallying cry of "Live with honour or die with glory" seems to be a win-win prescription for any budding martyr.)

So permanence is as intangible as swamp gas. The environment does change naturally; any other change is simply irresponsible.

Our next working bee to make weeds temporary is on Sunday August 19^th at 10:00am. Meet at the Bluff car park, B.Y.O gloves.