At HL you need two things the core does not ask for: a clear line between rewilding and habitat restoration, and the ability to explain recovery using positive feedback loops. Then you need case studies detailed enough to argue with.
📚 What you need to know
Rewilding lets habitats return to their natural state, reintroduces lost species and allows ecosystems to self-regulate with minimal management.
Habitat restoration repairs and regenerates damaged ecosystems, usually through human intervention and control.
A positive feedback loop is a process where the results of an action amplify that action over time.
In conservation, some positive feedback loops drive enhanced ecosystem recovery.
Limitations: land-use conflict, unintended consequences, and economic growth being prioritised over conservation.
You need at least two named projects with both benefits and limitations — the limitations are where most marks are lost.
Rewilding is not the same as habitat restoration
They overlap, and many real projects do both, but the underlying philosophy is different. Rewilding is process-led: set the conditions and accept whatever comes. Restoration is goal-led: decide what the habitat should look like and work towards it.
A rewilding project that has to be weeded, fenced and culled forever has quietly become a restoration project. Noticing that is a strong evaluation point.
Habitat restoration in detail
Habitat restoration aims to:
Repair and regenerate damaged ecosystems, often through human intervention and control.
Bring back lost biodiversity and restore ecosystem functions.
Use strategies such as replanting native species, removing invasive species, or rehabilitating degraded landscapes such as polluted rivers or deforested areas.
Positive feedback loops in recovery
You have met positive feedback as something destabilising. Here it works in your favour: once recovery starts, it makes further recovery easier.
Definition
A positive feedback loop is a process in which the results of an action amplify that action over time.
Positive feedback is why rewilding projects often look slow for years and then change quickly. It also explains why degraded systems can be so hard to shift: the same loop runs in reverse.
The two loops the syllabus names
Enhanced biodiversity. Reintroduced predators (wolves in Yellowstone) control herbivore populations, vegetation recovers, and the recovered vegetation creates valuable habitat for other species — which supports more of the food web.
Ecosystem equilibrium. Recovery through natural processes leads to healthier, more balanced ecosystems where species interact naturally rather than being managed.
Two concrete examples of the amplification:
Increased growth and biomass. As vegetation recovers, it supports herbivores and pollinators, which in turn feed predators, which sustains the ecosystem.
Enhanced reproduction and survival. A restored habitat raises survival rates, which leads to more reproduction, which further stabilises food webs.
Examiners love the phrase “which in turn”. If your answer contains two or three of them in a row, you are almost certainly describing a feedback loop properly rather than listing outcomes.
Benefits and limitations of rewilding
Benefits
Restores biodiversity: brings back species that play important ecological roles, producing healthier environments.
Improves ecosystem services: carbon sequestration, flood prevention and water purification, all of which benefit people too.
Promotes sustainable ecotourism: rewilded areas attract wildlife enthusiasts, giving local communities an income.
Limitations
Land-use conflict: competition between food production and rewilding, especially where land is scarce and farming matters to the economy.
Unintended consequences: reintroduced species can affect local ecosystems or people in unexpected ways — predators may threaten livestock.
Economic growth vs conservation: governments may favour mining or logging, stopping large projects before they start.
Four case studies
Pick two you can write about confidently. Knepp and Gorongosa make a good pair because they sit in very different economic contexts.
Case study 1
Knepp Estate, England
One of the best-known rewilding projects in the UK, in West Sussex. Formerly an intensively farmed estate, it turned to rewilding in 2001 after the land proved unproductive for conventional agriculture.
Instead of farming, the estate let nature take over, encouraging natural processes such as free-roaming grazing.
Increased biodiversity: grazing animals including longhorn cattle, Tamworth pigs and Exmoor ponies transformed the landscape, and rare species such as nightingales, turtle doves and purple emperor butterflies returned.
Natural regeneration: with less intervention the land regenerated on its own, producing a wider variety of habitats — wetland, scrubland and woodland.
Carbon sequestration: more natural vegetation, especially woodland, has stored more carbon.
Limitation — land-use conflict: the decision to move away from farming has been questioned, given pressure to produce food in the UK.
Limitation — economic viability: the project depends on ecotourism income and government grants, raising questions about whether it could survive without external support.
Case study 2
Affric Highlands, Scotland
One of Scotland’s largest rewilding efforts, aiming to restore natural habitats across around 500 000 acres.
Focus: reviving native forests and peatlands, both important carbon sinks, and bringing back wildlife once common in the region.
Restoration of native species: reintroductions including red squirrels and wildcats, with lynx under discussion.
Ecosystem services: restored peatland and forest improve water purification, flood regulation and carbon storage.
Cultural revival: Highland communities benefit from increased tourism and ecotourism.
Limitation — rural development: some local communities worry that large-scale rewilding will squeeze out agriculture and rural livelihoods.
Limitation — reintroduction conflict: bringing back top predators such as lynx faces opposition from farmers worried about livestock.
Case study 3
Oostvaardersplassen, Netherlands
An unusual project on reclaimed land that had originally been earmarked for industrial development.
Instead it became a nature reserve, with large herbivores — red deer, Konik horses and Heck cattle — introduced so that natural grazing would shape the landscape.
Landscape restoration: the grazers created a mosaic of grassland, wetland and scrub, allowing many plant species to grow and birds such as white-tailed eagles and spoonbills to return.
Natural processes: the project showed that rewilding could mimic natural processes without active management.
Limitation — harsh winters: the hands-off approach was heavily criticised when many herbivores starved during hard winters, raising the question of whether humans should intervene in extreme conditions.
Limitation — management dilemma: with no predators to control herbivore numbers, overgrazing and population booms followed, casting doubt on whether the system can really be self-sustaining.
Oostvaardersplassen is the most useful case study in this whole page, because it is the one that went wrong. Any question asking you to evaluate rewilding is far stronger if you can point to a project where the hands-off principle collided with animal welfare and public opinion.
Case study 4
Gorongosa National Park, Mozambique
Early in the 2000s the park began a major restoration effort after decades of civil war, during which many species were driven to local extinction by hunting and habitat destruction.
Restocking key species: elephants, lions, hippos and buffalo were reintroduced, restoring the park’s ecosystem dynamics and rebuilding predator-prey interactions.
Community involvement: the restoration brought job creation, ecotourism and education programmes, and the park is now seen as a symbol of Mozambique’s recovery.
Biodiversity recovery: research shows increases in both animal and plant species; Gorongosa is becoming a biodiversity hotspot again.
Limitation — human-wildlife conflict: as large predators and herbivores return, conflict with local communities, particularly farmers, becomes an ongoing management challenge.
Limitation — funding dependency: long-term success relies on sustained funding and continued collaboration between government agencies, NGOs and international partners.
EXAM QUESTION
Explain how a positive feedback loop can enhance ecosystem recovery in a rewilding project. [4]
Define
A positive feedback loop is where the results of an action amplify that action over time.
Apply it
Vegetation recovers, which supports more herbivores and pollinators, which in turn supports predators.
Close the loop
Those animals disperse seeds and return nutrients through dung and decay, so vegetation grows further and recovery accelerates.
Named example: after wolves were reintroduced to Yellowstone, vegetation recovery created habitat that supported still more species.Definition + at least three linked steps + example
EXAM QUESTION
Evaluate the success of one named rewilding project. [7]
Choose and describe
Knepp Estate, West Sussex: intensively farmed until 2001, then given over to free-roaming grazing by longhorn cattle, Tamworth pigs and Exmoor ponies.
Evidence of success
Return of nightingales, turtle doves and purple emperor butterflies; natural regeneration of wetland, scrub and woodland; increased carbon storage.
Evidence against
Land taken out of food production in a country under pressure to feed itself; financially dependent on ecotourism and government grants.
JudgementEcologically a clear success; economically and politically contested, so its long-term viability depends on continued external support.Both sides + a judgement that answers “success for whom”
💡 Exam tip
Keep rewilding and restoration separate in your definitions, then say that most projects use both.
Write feedback loops as a chain that returns to the start. If it does not loop back, it is not a feedback loop.
Two case studies is enough — but know each one well enough to give two benefits and two limitations.
Use Oostvaardersplassen when you need a project that failed in part. It is the strongest evaluation material here.
“Success” is not a single thing. Ask success for whom: ecosystem, local farmers, national economy?
Link back to ecosystem services whenever you list benefits — it connects this topic to the rest of the course.
⚠ Common mix-up
Positive feedback does not mean “good”. It means amplifying. It can drive collapse just as easily as recovery.
Rewilding is not restoration with a nicer name. Restoration targets a chosen end state; rewilding accepts whatever emerges.
Do not say Knepp “went back to how it was”. Nobody knows what it was. It became something new.
Reintroduced herbivores without predators are a problem, not a solution. That is exactly the Oostvaardersplassen lesson.
Ecotourism income is not guaranteed. It depends on access, safety and demand, all of which can vanish.
Listing case study facts without linking them to benefits or limitations gains very little in an evaluation question.
Up next: Judging Whether Conservation Worked (HL) — a structured three-level method for assessing any conservation project, which is exactly what evaluation questions are testing.
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