Federal Politics


Our unique environment is nearing the point of no return

National identity and our way of life are at risk if the warning signs continue to be ignored, warns BILL LAURANCE

Most Australians cherish strong feelings for their continent, its wild, untamed landscapes and many unique plants and animals. It is an elemental part of how we regard ourselves as individuals. It lies at the heart of our national identity.

What a tragedy it would be, then, if we were to permit those landscapes to disintegrate so that future Australians never see, enjoy, or learn to identify with them.

This could happen if the Australia they inherit is impoverished of native species, ravaged by destructive fires and athirst from failing water resources - with landscapes more closely resembling those of South America, Africa or Asia due to invasions of plant and animal pests.

That there is real risk of this happening is established in a report by 26 of the nation's leading ecologists from the Innovative Research Universities. ''The 10 Australian ecosystems most vulnerable to tipping points'' explores the drivers of profound ecosystem changes that scientists are now observing across the entire continent.

A tipping point, simply put, is a point of no return. In ecological terms, it is a threshold beyond which major change becomes inevitable.

This can happen when a rainforest dries out and is consumed by fire, when damaged coral reefs are smothered in seaweed, or savannas are invaded by exotic weeds. The move from one ecosystem state to another can occur with shocking suddenness. Very often the ecological balance is so disrupted that the original plants and animals cannot regain a foothold - even with our assistance. We have long read the warning signs. Among all the world's continents, ours has suffered the greatest extinction of its native mammals over the past century. Many small marsupials are now clinging desperately to survival. Creatures once plentiful across the continent linger only in sanctuaries, on offshore islands and in dwindling cloud forests on mountaintops.


Many Australians assume the sparsely inhabited savannas that span a third of our continent are pristine, or at least OK. Not so.

Ecologists are seeing these vast lands engulfed by introduced grasses which bring fires so fierce and frequent that even fire-loving Australian plants and animals cannot withstand them. The transformation of these landscapes is largely happening out of sight, out of mind. In our tipping-points study we looked at what drives all this - a vital first step in formulating a national plan to protect and preserve as much of the quintessential Australia as we can. We identified factors that make an ecosystem inherently vulnerable - like a reliance on specific physical environments or a few critical species - and we assessed the threats that imperil them.

These include global impacts, such as rising temperatures, acidifying oceans, extreme weather events and rising sea levels - and more local effects such as the loss and fragmentation of native vegetation, invasions of noxious weeds and feral animals, poor management of fire and water, rising salinity and pollution.

Our 10 most vulnerable ecosystems are, in order of criticality: cool mountaintops, tropical savannas, coastal wetlands (such as mangroves), coral reefs, drier rainforests, the Murray-Darling Basin, the south-west forests and sandplains, offshore islands, temperate eucalypt woodlands and forests, and river estuaries and their wetlands.

To limit the global impacts on these wounded ecosystems there is only one solution: to slow and then to reverse man-made climate change by reducing our emissions of carbon and other greenhouse gases.

If we are to avoid devastating tipping points, however, we must also reduce the cumulative impacts of local, as well as global, threats.

The vital principle in saving as much as possible of the Australia we know and love is this: act early, act local. There is a great deal that can be done locally - by governments, by industries, by companies, by NGOs, by communities and by dedicated individuals - that will help to prevent these vulnerable environments from reaching their tipping points.

Key countermeasures include reconnecting fragmented environments such as isolated patches of bush, forest and floodplains, and wiser management of fire and water in the landscape. Equally vital is combating the spread of invasive plants and animals and stopping new invaders before they can become established.

Avoiding unwise development and preserving highly threatened species are also essential.

All these goals are achievable, and in most cases they are affordable too. Indeed, many people are already doing great work through groups such as Landcare, Greening Australia and the like.

These efforts now require a stronger nationwide focus, one guided by a modern understanding of ecosystem vulnerability.

As with a hospital emergency ward, we can see which patients are in most urgent need of attention.

What is needed to save them is concerted national action.

This is a great and urgent cause for all who care about the future of this country, its unique natural heritage - and the identity as Australians which it bestows on us.

Bill Laurance is Professor of Conservation Biology at James Cook University and lead author of ''The 10 Australian ecosystems most vulnerable to tipping points'', Biological Conservation, vol. 144, Elsevier, 2011.