The big idea: Ex situ conservation means protecting a species away from its natural habitat — for example in a zoo, a botanic garden or a seed bank.
("Ex situ" is Latin for off-site. The opposite, in situ, means protecting a species in its own habitat, such as in a nature reserve.)
It is a back-up plan: it keeps a species alive when its wild habitat is too damaged, too small or too dangerous for it to survive there right now.
- Ex situ conservation
- Protecting a species OUTSIDE its natural habitat — e.g. in a zoo, botanic garden, captive-breeding centre, seed bank or gene bank.
- In situ conservation
- Protecting a species INSIDE its natural habitat — e.g. by setting up a nature reserve or national park.
- Captive breeding
- Breeding endangered animals under human care to raise their numbers, often aiming to release them back into the wild.
- Seed bank
- A store where seeds from many plant species are kept cold and dry so they stay alive for decades as a back-up.
Two words to keep straight: In situ = IN the habitat (in the wild).
Ex situ = EX-ternal to the habitat (off-site, e.g. a zoo).
If the protected animals or seeds are not in the wild, the method is ex situ.
The two approaches side by side. In situ (left) protects the species in its natural habitat — a nature reserve — keeping the whole ecosystem and natural behaviour. Ex situ (right) protects it off-site in a zoo, seed bank or gene bank as a back-up. The reintroduction arrow shows ex situ feeding individuals back to the wild — the two work best together.
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Ex situ conservation does not just store a species — it actively tries to increase its numbers and keep its genes safe so the species can one day return to the wild.
It does this in a few main ways:
| Method | What it does | Example use |
|---|---|---|
| Captive breeding (zoos) | Breeds animals safely, away from predators and poachers, to raise numbers | Building up a small population of a rare big cat |
| Botanic gardens | Grow and protect rare plants, and study how to germinate them | Keeping rare orchids alive and propagating them |
| Seed banks | Store many seeds, cold and dry, as a long-term genetic back-up | Saving thousands of crop and wild-plant varieties |
| Gene / tissue banks | Freeze cells, sperm or eggs to preserve a species' genetic variety | Keeping frozen samples of a critically endangered frog |
Why this helps an endangered species
- Animals breed safely — away from predators, poachers and disease
- Numbers can be raised quickly under expert care, then individuals reintroduced to the wild
- Genetic variety is preserved (studbooks and gene banks avoid too much inbreeding)
- It is a safety net: the species survives even if its wild habitat is destroyed
- Captive populations support research and public education, raising funds and support
Why it is only a back-up: Ex situ conservation has real limits.
It is expensive and can only hold small numbers, so genetic variety may still be lost over time (inbreeding).
Animals raised in captivity may struggle to survive when released, and — crucially — the species' natural habitat is not protected. So ex situ work is best used alongside in situ conservation, not instead of it.
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How this is tested: This sub-topic is examined as a short Explain or Discuss question.
A common task is to explain how ex situ conservation helps preserve an endangered species — so you need to give clear reasons (breed safely, raise numbers, save genes, reintroduce, act as a back-up), not just a list of places.
Mark schemes credit one mark per distinct reason, so aim for as many separate points as the marks allow.
IB-style question — explain ex situ conservation
A species of forest parrot has fewer than 60 birds left in the wild, and its forest is still being cleared. Conservationists set up a captive-breeding centre for the parrot. Explain how this ex situ programme helps preserve the species. [4]
How to build a 4-mark answer
- Make a point about safety. In the centre the parrots breed away from predators, poachers and habitat clearance, so more chicks survive.
- Make a point about numbers. Under expert care the population can be raised quickly, building a larger, safer back-up population.
- Make a point about genes. A studbook / gene bank keeps track of breeding so genetic variety is preserved and inbreeding is reduced.
- Answer the command term — say HOW it preserves the species. Once numbers and habitat allow, captive-bred parrots can be reintroduced to the wild, so the species is preserved even though its wild habitat is still threatened.
Final answer
Ex situ breeding lets the parrots breed safely away from predators/poachers/clearance, raises their numbers under expert care, preserves genetic variety through managed breeding, and provides birds to reintroduce — so the species survives even while its wild habitat is at risk.
What scored the marks: Four separate reasons, each a different idea: safe breeding, raised numbers, genetic variety preserved, and a back-up for reintroduction.
Listing places ("zoo, seed bank, botanic garden") with no reasons would not score on an Explain question.