RewildingSpec D4.2.11
In short
Rewilding is the restoration of natural processes in ecosystems so that they become self-sustaining. Methods include reintroduction of apex predators and other keystone species, re-establishment of connectivity of habitats over large areas, and minimisation of human impact, including by ecological management. At Hinewai Reserve in New Zealand, native forest is regenerating through gorse.
Rewilding aims to restore natural processes so that an ecosystem can sustain itself with as little human management as possible.
- Reintroduction of apex predators and other keystone species: grey wolves were returned to Yellowstone National Park, USA, in 1995. Studies reported less browsing by elk and regrowth of willow and aspen in some areas, although the size of the effect is still debated.
- Re-establishment of connectivity of habitats over large areas: wildlife corridors link fragments so populations can move, find mates and exchange alleles.
- Minimisation of human impact, including by ecological management: removing livestock, controlling invasive species, then stepping back.
Hinewai Reserve, New Zealand
Hinewai Reserve on Banks Peninsula, South Island, is former sheep farmland that had become covered by gorse, an introduced shrub. Since 1987 it has been managed with minimal interference. Grazing animals were kept out, and the gorse was not burned or sprayed. Gorse acts as a nursery: native tree seedlings grow up through it, then overtop and shade it out. Native forest is now regenerating over more than 1 000 hectares.
Linking question: what is the distinction between artificial and natural processes? Rewilding uses a human decision to let natural processes take over again.
Quick check
Name the four requirements for ecosystem stability.
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Supply of energy, recycling of nutrients, genetic diversity, climatic variables within tolerance levels.
When is harvesting sustainable?
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When the rate of harvesting is lower than the rate of replacement.
What does BOD stand for?
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Biochemical oxygen demand.
Why are sealed glass vessels preferred for mesocosms?
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Matter cannot enter or leave, but energy transfer is still possible.
Written and checked against the IB Biology SL specification · Updated October 2026