Lava Fields Are Colonised From The Air

Fresh lava is one of the few surfaces that begins with nothing at all. No soil, no seeds and no organisms, which makes it a rare record of how ground becomes habitat.

The starting condition is genuinely blank

Most bare ground carries a legacy. A cleared field holds a seed bank, a landslide scar holds soil and fragments of root, and both recover partly from what survived.

Lava has none of that. Everything present must arrive from outside, and the surface offers no water retention, no nutrients and extreme temperature swings.

Because eruptions are dated, the age of each surface is known exactly. Comparing flows of different ages gives a sequence rather than an inference.

The first arrivals travel light

Lichens and mosses establish first, because their spores are small enough to be carried long distances on the wind and they tolerate surfaces that hold almost no water.

Lichens also work chemically on the rock, releasing acids that free minerals and begin the slow production of fine material in cracks and hollows.

Mosses then trap wind-blown dust and their own dead tissue, and the shallow organic layer that accumulates is the first thing a rooted plant can use.

Surface texture decides the pattern

Colonisation is patchy rather than even. Rough, broken flows offer crevices that shelter seedlings, hold moisture and collect drifting material.

Smooth, unbroken surfaces stay bare far longer, since there is nowhere for dust to lodge and nothing to shade a germinating plant from the surface heat.

Islands of older ground surrounded by a flow accelerate everything nearby, acting as a local seed source while everything else waits on the wind.

Animals arrive before the vegetation supports them

Bare flows carry a scavenging community from an early stage, living on insects blown in and deposited by wind rather than on anything growing locally.

Spiders and ground beetles are typical of this phase, and they are among the first animals recorded on new ground because the food supply is imported.

Seabirds contribute in coastal settings, bringing nutrients from the sea and depositing them where they roost, which produces green patches long before the rest greens.

Introduced species alter the sequence

Because the starting point is empty, whatever arrives first has an outsized influence, and an introduced plant can occupy new ground before native colonists reach it.

Grazing animals have a similar effect, removing slow-growing pioneers that took decades to establish and preventing the organic layer from accumulating.

Trampling matters for the same reason. A lichen crust broken by boots on a young flow represents many years of growth and will not be replaced quickly.