Need for several approaches to conservation of biodiversity
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Question
Define in situ conservation.
Answer
Protecting a species **within its natural habitat** (e.g. in a nature reserve or national park).
Question
Define ex situ conservation.
Answer
Protecting a species **away from its natural habitat** — e.g. in a zoo, botanic garden, seed bank or gene bank.
Question
Define rewilding.
Answer
Restoring the **natural processes** of a degraded ecosystem so it becomes **self-sustaining**, often by reintroducing a **keystone species**.
Question
Define a keystone species.
Answer
A species whose effect on its ecosystem is **far larger than its numbers** suggest (e.g. a top predator or a beaver).
Question
Give three ex situ methods.
Answer
**Captive breeding** (zoos), **botanic gardens**, and **seed / gene banks**.
Question
Define a degraded ecosystem.
Answer
An ecosystem that has been **damaged** so it works less well (e.g. a cleared forest or drained wetland).
Question
Give two examples of in situ conservation.
Answer
**Nature reserves / national parks** and **wildlife corridors** that connect them.
Question
State the main advantage of in situ conservation.
Answer
The **whole ecosystem** is conserved together, so the species keeps a large population with **high genetic diversity** and behaves naturally.
Question
What is the flagship method of rewilding?
Answer
Reintroducing a **keystone species** to restart natural processes across the ecosystem.
Question
What is captive breeding?
Answer
Breeding endangered animals **under human care** to raise their numbers, often to **reintroduce** them to the wild.
Question
What is a seed bank?
Answer
A cold, dry store of seeds from many species kept as a **long-term genetic back-up**.
Question
Name a rewilding method that is NOT a keystone reintroduction.
Answer
Restore natural **water flow** (re-flooding), re-establish natural **grazing**, let **native plants** return, or reconnect habitats with **corridors**.
Question
What is a wildlife corridor?
Answer
A protected strip of habitat that **connects two separate reserves** so animals can move between them.
Question
How does a wildlife corridor help biodiversity?
Answer
It lets animals **move, interbreed and recolonise** between reserves — keeping populations larger and genetically diverse.
Question
How does rewilding differ from ordinary conservation?
Answer
Conservation protects species and often needs **ongoing management**; rewilding restores **natural processes** so the ecosystem **manages itself**.
Question
How does ex situ help raise numbers?
Answer
Animals breed **safely** (away from predators/poachers) under expert care, so the **population grows**.
Question
Define habitat fragmentation.
Answer
The breaking up of one large habitat into **smaller, separated patches**.
Question
How do gene/seed banks help conservation?
Answer
They **preserve genetic variety** so a species can recover even if wild populations are lost.
Question
Why can reintroducing one keystone species restore a whole ecosystem?
Answer
Its activity (e.g. damming or predation) restarts a **chain** of natural processes that many other species depend on.
Question
What is the edge effect?
Answer
The **harsher conditions** (wind, light, predators, invasive species) found **near the boundary** of a habitat patch compared with its interior.
Question
Give an example of a keystone reintroduction in rewilding.
Answer
**Beavers** — they build dams that restore water flow and create wetland that supports many species.
Question
What is reintroduction?
Answer
**Releasing** captive-bred individuals back into a (protected) **natural habitat**.
Question
Give two limitations of ex situ conservation.
Answer
It is **expensive** and holds **small numbers** (inbreeding risk); it also **does not protect the habitat**.
Question
Which reserve shape protects the most species, and why?
Answer
A **large, rounded** reserve — it has **more sheltered interior** and **less exposed edge**.
Question
What does 'ecosystem restoration' mean?
Answer
Repairing a **damaged** ecosystem so its **natural processes** and **biodiversity** recover.
Question
Why can captive-bred animals struggle after release?
Answer
They may **lack survival skills** learned in the wild, so they can struggle to find food or avoid predators.
Question
How does rewilding help minimise biodiversity loss?
Answer
By restoring natural processes in a **degraded** ecosystem, it **reverses** damage so more species can return.
Question
Why is a long, thin reserve poor at protecting species?
Answer
It is **almost all edge**, so harsh edge conditions reach every part and few interior species survive.
Question
Why is ex situ called a 'back-up'?
Answer
It keeps a species alive when its **wild habitat is too damaged**, but it does not protect that habitat — so it works **best alongside in situ**.
Question
Why does in situ conservation keep genetic diversity high?
Answer
The wild population stays **large**, so a wide range of alleles is kept (unlike a small captive group).
Question
Name two natural processes rewilding tries to restore.
Answer
Any two of: **grazing**, **predation**, **flooding/water flow**, **seed dispersal**.
Question
In a 'rewilding methods other than keystone reintroduction' question, what must each method do?
Answer
Restore a **natural process** (not just add a species) — e.g. re-flooding or letting native plants return.
Question
In situ vs ex situ — one key difference?
Answer
**In situ protects the habitat** (the species stays in the wild); **ex situ does not** (the species is held off-site).
Question
Why is in situ often preferred over ex situ?
Answer
It conserves the **whole habitat/ecosystem** and lets the species **behave and evolve naturally**, not just survive in captivity.
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