Australia's living systems

Australia is one of the strangest and richest places for life on Earth, and much of what lives here lives nowhere else. That makes our nature globally important and also uniquely vulnerable, because when something is found only here, losing it here means losing it everywhere. This lesson is about what makes our living systems special and what protecting them looks like.

Why Australia is so unusual

The reason is time and isolation. Australia drifted apart from other land masses long ago and stayed separate for a very long time, so life here evolved down its own path. The result is that most of our mammals, reptiles and flowering plants are endemic, meaning they are found only in Australia. Kangaroos, koalas, platypus, and thousands of less famous species are ours alone. There is nowhere to import a replacement from if they vanish.

Isolation on its own does not make new species, so it is worth seeing how the two fit together. When a group of animals is cut off with no competitors arriving from elsewhere, evolution fills the empty roles with whatever raw material is already present. In Australia that material was mostly marsupials, mammals that raise their young in a pouch, and over millions of years they evolved into forms that do the jobs other mammals do elsewhere. The kangaroo grazes like a deer, the wombat digs like a badger, the sugar glider glides like a flying squirrel, the thylacine hunted like a wolf until we lost it. Same problems, different starting material, so the solutions look familiar but are built from a separate branch of the family tree, which is exactly why they exist nowhere else.

Fire, and the people who managed it

Much of Australia is shaped by fire. Many of our plants are fire adapted, meaning they do not just survive fire but need it to release seeds or trigger new growth. This is not new. Aboriginal and Torres Strait Islander peoples managed this land with fire for tens of thousands of years, using careful, cool burns to shape country, reduce dangerous fuel loads and help plants and animals thrive. This is one of the longest running land management traditions on Earth, and it is being recognised again as part of caring for country today.

It is worth being clear about how that fire management actually worked, because it is easy to picture as simply lighting fires. The skill was in the opposite of a big fire. Cool burns are lit in the right season, early, when the ground is still damp, so the fire creeps along the surface, clears the built up leaf litter and dead grass, and goes out on its own without reaching up into the canopy. Done patch by patch across the country, this leaves a mix of recently burnt and longer unburnt ground, which stops any single fire from finding enough fuel to become an unstoppable one, and gives animals unburnt patches to shelter in and fresh regrowth to feed on. When that management stopped over much of the country, the fuel built up year after year, which is part of why the fires we now get can be so large and so hard to control.

The ancient systems

• The Daintree and other tropical rainforests: among the oldest continuously surviving rainforests in the world, holding species that go back to an ancient past.
• Alpine areas: the high country, with its own specialised plants and animals living in a narrow band that warming squeezes.
• Tall eucalypt forests: home to some of the tallest flowering plants on the planet and to animals that depend on old, hollow bearing trees.

One find shows both the age and the fragility at once. In 1994 a park officer walking a remote gorge in the Blue Mountains came across a stand of trees that turned out to be a species known until then only from fossils tens of millions of years old, the Wollemi pine, still alive in a single hidden pocket and nowhere else on Earth. Fewer than a hundred wild trees were left. It is a reminder that some of these ancient survivors hang on in one valley, and that a single fire or disease in the wrong place could end a lineage older than many mountain ranges in an afternoon.

What makes these systems fragile is often the very thing that makes them special. Species that evolved in one narrow place, for one set of conditions, have nowhere to go when those conditions change or when the habitat is cleared. A specialist cannot simply move to the next valley if the next valley is a paddock or is now too warm.

A common misconception

Aren't the national parks enough? If we have set land aside, surely what is inside is safe? A park is necessary, but a line around a map is not the same as a working system. Introduced predators and weeds cross park boundaries as if they were not there, fire management does not stop at the sign, and a species locked inside a single reserve with no way to reach the next one is still a small, isolated population of the kind that winks out. Protection is less about drawing a boundary around land and more about keeping what is inside it connected, controlled and cared for, which is why the work never really ends.

What protecting them looks like

Protection is not one grand act. It is a lot of steady work: keeping habitat connected so animals can move, controlling introduced predators and weeds, bringing back good fire management, protecting old growth trees and the hollows animals nest in, and funding the people who do this on the ground. A growing part of that work is led by Indigenous rangers, who combine tens of thousands of years of knowledge with modern science to manage vast areas of country. When you picture protecting Australian nature, picture those people, not just fences and signs.

Where this is near you

This is not only a story about remote wilderness. Most towns have a patch of remnant bush, a creek line or a coastal reserve that is a genuine piece of an old system, holding local species that may live nowhere else nearby. You can learn which plants and animals in your area are native and which are introduced, plant local native species rather than exotic ones in a garden so they feed local birds and insects, keep a cat from roaming, and record what you see on a citizen science app so that the people managing these places have more eyes than their own. None of it is dramatic, but steady local care is most of what protection actually is.

That ties the whole topic together. The first lesson explained why the living world is worth keeping, the second and third told the honest story of what is being lost on land and at sea, and this lesson explains why Australia in particular has so much that exists nowhere else and so cannot be replaced. The case study that follows puts a single face on all of it, the eastern barred bandicoot, and shows what the steady, unfinished work of protection looks like when it is aimed at one species over decades.