Rewilding at Higher Level: The same statement as SL, with different real projects: Knepp in England, beavers in Scotland, the Elwha dams, Iberá in Argentina. At HL you also meet the law (protected species status for beavers) and the ethics of letting nature decide. HL 3.3.11 and 3.3.12 then weigh what rewilding achieves.
Practise this as you read
- Explain how each rewilding method regenerates a natural process.
- Discuss how reintroducing a species can affect an ecosystem and the people nearby.
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Helping nature heal itself: Rewilding means letting nature repair itself. Think of a trampled lawn: stop walking on it and it grows back. Natural processes in ecosystems can be regenerated by rewilding.
The points to remember
- Rewilding restores an ecosystem's natural processes, so that it can run itself again.
- The processes: predation and grazing, seed spreading, flooding and natural regrowth (succession).
- People step back: less management, control and harvesting as the ecosystem recovers.
- It works best over large, connected areas.
- The aim: a self-sustaining ecosystem with more biodiversity and resilience.
Bring back
- Knapdale, Scotland: Eurasian beavers from Norway were released in 2009.
- Beavers had been hunted out of Britain about 400 years earlier.
Join up
- The European Green Belt: a 12 500 km strip of wild land along the old Iron Curtain, linking reserves in 24 countries.
Stop
- Knepp, England: dairy and arable farming stopped in 2001 on 1400 hectares.
Step back
- Elwha River, USA: two dams were removed in 2011 to 2014; salmon swam upstream again.
Remember it as: Bring back, join up, stop, step back.
Real example: the Knepp Estate in Sussex, England, lost money on farming heavy clay soil. In 2001 its owners stopped farming and let the land rewild; it is now one of England's richest places for wildlife.
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The first method brings back the missing animals: the apex predator and the keystone species. Their effects spread through the whole food web as a trophic cascade.
How returning species regenerate processes
- An apex predator hunts grazers that nothing else controls, e.g. wolves eat and scare elk.
- Fewer, warier grazers let young trees and plants regrow: a trophic cascade down the food chain.
- A keystone species has a large effect for its numbers: beavers build dams that make ponds and wetlands.
- Returning species rebuild food webs, habitat variety and processes people cannot run by hand.
- Reintroduction brings back a native species; introducing an alien species can make it invasive.
Dams
- Beavers fell trees and dam streams in Knapdale and Tayside.
Ponds
- The water backs up into ponds and wet meadows.
Life
- Frogs, dragonflies, fish and water plants increase.
Water
- Dams slow floods and trap soil washed off the land.
Real example: beavers from Norway were released at Knapdale, Scotland, in 2009 in an official trial. Others escaped or were released illegally on the River Tay, and by 2020 Scotland had about 1000 beavers. In 2019 they became a protected species.
Show the chain: Wolves return, so elk fall and move; so young trees regrow; so birds, beavers and fish return. One step per point, each with 'so'.
The second method joins wild areas back together with wildlife corridors, so that animals and plants can spread across a whole landscape again.
The points to remember
- Many wild areas are fragments: islands of habitat cut off by farms, roads and towns.
- Wildlife corridors, green bridges over roads and underpasses join them up.
- Animals can then move to find food and mates, and shift their range as the climate changes.
- Large joined-up areas hold viable populations of wide-ranging animals, with more gene flow.
- Rewilding plans link reserves across whole landscapes, even across borders.
Real example: the Yellowstone to Yukon plan links parks along about 3200 km of the Rocky Mountains, so a wolf or grizzly bear can travel from the USA into northern Canada. The European Green Belt does the same along the old Iron Curtain.
Why size matters: A wolf pack needs hundreds of square kilometres. A small, cut-off reserve cannot hold enough wolves to breed without inbreeding.
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The third and fourth methods are about people doing less: stop using the land, then let natural succession do the work, stepping in only where nature cannot fix a problem alone.
The points to remember
- Stop farming, logging, fishing or hunting on the land (cessation of agriculture and harvesting).
- Let natural regeneration happen: seeds blow or are carried in, and succession rebuilds the vegetation.
- Remove human influence: take out fences, drains and dams, so rivers can flood and move again.
- Use ecological management only where needed: control invasive species, cull deer or goats that have no predators.
- Then step back and monitor: interfere less as the ecosystem looks after itself.
Remember it as: Stop taking, then step back.
Stopped
- Ploughing, dairy cows and fertiliser ended in 2001.
- Internal fences were taken down.
Stand-ins
- Longhorn cattle, Exmoor ponies, Tamworth pigs and deer roam free.
- They graze, trample and root like lost wild animals.
Result
- A mix of scrub, grass and trees.
- Turtle doves, nightingales, purple emperor butterflies and nesting white storks.
Real example: wild cattle and horses that once grazed England are extinct, so Knepp uses proxy animals. In 2020 white storks bred there, the first in Britain for over 600 years.
Real projects combine the methods. Most follow the same steps.
The steps of a rewilding project
- Stop the damage first: poaching, war, farming or hunting.
- Bring back the missing species, often from other parks or countries.
- Protect and join up enough land for them.
- Involve local people: jobs, health and a share of the income win their support.
- Monitor numbers, then step back as the ecosystem recovers.
What was done
- Cattle ranches were bought and made a national park (2018).
- Jaguars returned in 2021 after 70 years.
What came back
- Giant anteaters, pampas deer, red-and-green macaws.
- Otters and peccaries released too.
People
- Former hunters became guides.
- Wildlife tourism brings jobs to nearby towns.
Real example: the Iberá wetlands in Argentina lost their jaguars, giant anteaters and macaws to hunting and ranching. Tompkins Conservation and the Argentine government have brought back more than ten species since 2007. Gorongosa, in Mozambique, has done the same since 2004.
Nature and people together: Projects last when local people gain from them. Wildlife does not see borders, so countries also have to work together.
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Regenerating damaged land is not simple. A paper may give a model of land degradation and a fact file and ask for the problems.
Problems in restoring degraded land
- Cost: restoring land is expensive and labour intensive, and the longer it is left, the more it costs.
- Success falls with time: the further the land has degraded, the lower the chance of recovery.
- Unforeseen effects: a plant sown to stop erosion can turn invasive and crowd out native plants.
- Fixes can harm: herbicides pollute water; mowing or grazing the invader can expose soil to erosion.
- Nature and the wider world: a harsh climate, poor soils, or a global cause such as climate change.
Real example: at Oostvaardersplassen in the Netherlands, cattle, horses and deer were put in a fenced reserve with no predators. Numbers rose to about 5000, and in the hard winter of 2017 to 2018 about 3000 died or were shot.
Link success to time: 'It might not work' is too thin. Say why: 'the longer the land is left, the less soil and seed remain, so the lower the chance of success'.
Bringing a species back brings gains and problems. A paper may ask for one of each, for one mark each.
Reintroductions: gains and problems
- Benefits: new habitats and biodiversity (beaver ponds), ecotourism, a former ecosystem restored, food for other species, wetlands back.
- Problems: damage to property and crops, flooding when dams collapse, conflict with landowners and farmers.
- Ecological risks: upset food webs and competition, short-term change to existing habitats.
- Survival risks: animals may not adapt and die; poaching; genes unlike the original stock; no predator to limit numbers.
Gain, with its effect
- Storks at Knepp draw visitors: ecotourism.
- Lynx would eat roe deer, so young trees could regrow.
- A lost species returns to its former range.
Problem, with its effect
- Sheep farmers fear lynx attacks on lambs.
- With no predators, grazers can outgrow their food.
- Poaching is a risk where many people live.
Real example: on the River Tay, Scotland, beaver dams flooded farmland, and in 2019 more than 80 beavers were legally shot to protect crops, while others were moved to new rivers.
Two answers that do not score: 'Beavers build dams that regulate water flow' is not a benefit on its own: add the effect. And a native species brought back is not 'an alien' or 'invasive species'.
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How this comes up: Paper 1 gives a case study with a model and a fact file: problems of restoring land [4], a benefit or a problem of a reintroduction [1]. Paper 2 Section B asks you to explain or discuss rewilding with named examples [7] or [9].
The Knepp Estate in southern England stopped farming in 2001 and is now described as a rewilding project.
Explain how rewilding can regenerate natural processes in ecosystems. Refer to named examples.
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One point per paragraph: Each mark is one point. Put each in its own paragraph, so every step of the chain is easy to see.