The ideas
Concepts
One idea to a page, to look up whenever a guide raises one you don't know. A handful of keystone ideas do most of the work of reading the coast, so start there, then follow a thread as far as you like. If you'd rather be taught in order, take a pathway.
Keystone ideas
The few worth carrying everywhere. Each one explains a lot of the rest.
Habitat connectivity (get from patch to patch)
An isolated patch cannot replace what it loses. Corridors are how the neighbours get back in.
Keystone idea · Chapter 18Mend the conditions, not the thing
You do not glue a rainforest back together tree by tree, or vaccinate a koala back to abundance. Restoration works from the conditions up.
Keystone idea · Chapter 7The gradient rule (substrate writes the country)
Geology writes the rules, soils translate them, living things live them out, and people change them. Rainfall has less say than you would think.
Keystone idea · Chapter 4The nitrogen–phosphorus asymmetry
A soil can win nitrogen back from the air. Phosphorus comes only from rock, and the oldest sand is almost out of it.
Keystone idea · Chapter 9Why the poorest ground grows the richest flora
Starve the ground and you would expect fewer plants. On the oldest sand the opposite happens, and the reason comes in two halves.
More concepts
The wider vocabulary. Pull on whichever thread the country hands you.
Acid-sulfate soils (the buried acid)
The coastal floodplains have spent thousands of years storing fool's gold in the mud. Drainage is what wakes it.
Concept · Chapter 4Basalt fertility (why red ground grows rainforest)
Basalt is young rock. It weathers to a red clay that keeps hold of the water and nutrients sand lets run straight through.
Concept · Chapter 17Biological invasion (they don't add — they overwrite)
A native animal's defences are built against the neighbours it grew up with. The fox and the cat were not among them.
Concept · Chapter 5Blackwater and acid water (the colour of tea)
The water of the sand country runs the colour of black tea and roughly as sour as orange juice. It is also clean.
Concept · Chapter 17Coastal squeeze (nowhere to retreat)
Given room, a tidal marsh climbs inland ahead of a rising sea. Much of this coast's low country has a wall behind it instead.
Concept · Chapter 5Dune lakes (perched and window)
A lake in a heap of bottomless sand ought to drain straight through. Two quite different things stop it.
Concept · Chapter 8Estuarine zonation (the tide sorts the bands)
Seagrass, mangrove and saltmarsh lie in stripes across a tidal flat, each at the height where it can just bear the salt and the soaking.
Concept · Chapter 12Hollow dependence (the century-old apartment)
A eucalypt cannot grow a hollow. Fungi, termites, fire and rot have to excavate one, and they barely begin before the tree turns a hundred.
Concept · Chapter 8How a mangrove beats salt and mud
Seawater is poison and tidal mud holds no oxygen. A handful of unrelated trees grow there anyway.
Concept · Chapter 15Plant partnerships (the deals for poor ground)
On poor sand, hardly any plant feeds itself. It buys what it needs underground, and pays in sugar.
Concept · Chapter 4Podzolisation (how sand goes bankrupt)
Rain and rotting leaves rinse the colour out of sand and stack what they remove into a hard dark floor below.
Concept · Chapter 13Rainforest structure (the layered forest)
A rainforest is stacked in storeys, and the whole stack holds only as long as the green ceiling above it stays shut.
Concept · Chapter 4Sclerophylly (the tough-leaf economy)
Hard, stiff, waxy leaves gave a whole style of Australian bush its name. That hardness is the visible result of a nutrient the ground cannot replace.
Concept · Chapter 14Seagrass meadows (the inshore pasture and nursery)
Pasture for the dugong, nursery for the fishery, and it lives or dies by how much light gets down through the water.
Concept · Chapter 9Serotiny (banking seed for fire)
Some heath plants bank their seed for a decade or more, locked in cones or buried in the sand, until fire opens it.
Concept · Chapter 16Species dependence (a life is a bundle of needs)
Every animal carries a list of things it cannot do without. A forest can look whole and still be missing one of them.
Concept · Chapter 6The fire boundary (how flame draws the line)
The line where rainforest meets gum forest looks like a soil boundary. Right at the join, fire draws it, and redraws it.
Concept · Chapter 6The fire mosaic (no single right fire)
Burn a whole landscape at once and it all comes back the same age. The variety is in the patchwork.
Concept · Chapter 14Two oceans on one rock (the tropical–temperate overlap)
Tropical coral and cool-water sponges grow on the same headland boulder here, a few metres down. One current explains it.
Concept · Chapter 2Weathering — how rock becomes soil
Rock does not stay rock. The same weather turns basalt into rich red clay and quartz sand into a bleached, hungry podzol.
Concept · Chapter 10Wetland zonation (the swamp reads like a tide-gauge)
In a freshwater swamp, where a plant stands tells you how many days a year its feet are underwater.