Mochi Isle
Pioneer plants · Chimney VolcanoScience for kidsWhat grows first on new rock?
In short: Fresh lava has no soil, so the first living things to move in are tough pioneers such as lichens, mosses and ferns. Slowly they turn rock into a thin layer of soil, so grasses, shrubs and finally trees can follow. This is called succession.
How it works
New lava rock is hard and bare. It has no soil and holds no water, so most plants can't grow there. But the wind carries in the dust-like spores of lichens and mosses, which settle in tiny cracks. A lichen is a partnership between a fungus and an alga, and it can cling to bare rock.
Lichens give off a weak acid that slowly eats tiny pits into the rock, while frost and rain crack it too. Mosses act like little sponges, holding water and dust. When they die and rot, they mix with rock crumbs to make the first thin soil. Ferns often take root early in damp cracks.
As the soil thickens, grasses and small shrubs move in and drop leaves, making the soil deeper and richer. Eventually trees can send down deep roots and a forest grows. Going from bare rock to forest can take hundreds of years or more. This step-by-step change is called succession.
Where to see it in New Zealand
Rangitoto Island in Auckland is a great place to see pioneer plants. On its black lava, only a few hundred years old, lichens and mosses moved in first, and pōhutukawa later took root in the cracks. Today much of the island is covered in forest, while some lava fields are still almost bare.
Try it together
With an adult, look at old stone walls, steps, boulders or tree trunks for patches of grey, green, yellow or orange lichen, and for moss in the cracks. Use a magnifying glass, but don't peel them off. Which grows more: the sunny side or the shady side?
Kids also ask
What's the difference between lichen and moss?
Moss is a plant with tiny leaves and is usually soft and green. Lichen isn't a plant: it's a fungus and an alga living together, often looking like flat, crusty patches in grey, green, yellow or orange.
Why are pioneer plants so important?
Without them, bare rock would struggle to become soil. They lay the foundations by trapping water and nutrients, so other plants, and then animals, can move in after them.
In the game, “Pioneer plants” is a nature card on Chimney Volcano.
Your child finds this card by reaching the right place or meeting the right weather on the island, and lights it up by answering the question on the back. Tap the button below and the game shows your child which island it is on and how to find it. Mochi Isle is a browser learning game for ages 5 to 18; the main island and the daily lesson are free.
Find “Pioneer plants” on the island ↗ All cards from Chimney Volcano