Ex-situ Conservation: Zoos, Seed Banks, Cryopreservation

Ex-situ conservation means protecting species outside their natural habitat, in places made by humans. Zoos, botanical gardens, seed banks and cryopreservation are key methods when wild habitats are unsafe or populations are too small.

This approach acts as an insurance backup. Seeds and genetic material stored today can help restore species tomorrow, and captive animals can be reintroduced when threats are controlled.

Key Concepts

Zoo keeps live animals for breeding, education and research. Botanical garden grows live plant collections with records. Seed bank stores seeds at low temperature and low moisture to keep them viable for years. Cryopreservation stores seeds, sperm, eggs or tissues at very low temperature, often in liquid nitrogen at -196 degrees Celsius. Gene bank is a broader term for stored genetic material. Viability is tested as germination percentage.

How It Works

1. Scientists collect seeds or animals from the wild following legal and ethical rules, keeping records of origin.
2. Seeds are dried to about 3 to 7 percent moisture and sealed in airtight packets.
3. Packets are stored at -18 degrees Celsius in seed banks; tissues for cryopreservation go to -196 degrees Celsius.
4. Zoos and gardens breed individuals using studbooks to avoid inbreeding and maintain genetic diversity.
5. When habitat is restored, healthy individuals are reintroduced and monitored.

Worked Example

A seed bank stores 1,000 seeds of a rare plant. Germination test on 100 seeds shows 85 sprout.

Step 1: Viability = 85 / 100 x 100 = 85 percent.

Step 2: Expected viable seeds in storage = 1,000 x 0.85 = 850.

Step 3: If managers want at least 500 plants in reintroduction and field survival is 50 percent, seeds needed = 500 / 0.50 = 1,000 viable seeds required, so more collection is needed.

This shows how simple percentages guide storage targets.

Common Misconceptions

• Zoos are only for display. Modern zoos run breeding programmes for endangered species like red panda and pygmy hog.
• Seed banks solve all plant loss. Some seeds are recalcitrant and cannot survive drying, so they need cryopreservation or live collections.
• Ex-situ replaces habitat protection. It is a complement; without wild habitat, reintroduction cannot succeed.

Real-World Applications

The National Bureau of Plant Genetic Resources in India stores crop varieties for farmers and breeders. Svalbard Global Seed Vault in Norway backs up world crops. Zoos breed and release species such as the Arabian oryx successfully. Botanical gardens cultivate medicinal plants, reducing pressure on wild populations.

To conclude, ex-situ methods secure species off site in zoos, gardens, seed banks and cryostorage, preserve genes and enable future restoration when combined with habitat protection.