Even as they fall under increasing pressure from human activity, the restoration of natural habitats like forests, is a key component of rapid transition. Not only is it a vital defence against climate breakdown, but it also protects the web of life and is beneficial for human well-being too. This ‘rewilding’ has caught the public imagination, sometimes with trepidation where the reintroduction of certain species are concerned, but the speed of attitude change is illustrated by the television naturalist, David Attenborough, whose long-awaited embrace of climate activism has recently seen new documentaries on both the BBC and Netflix. As recently as 2016, Attenborough was hesitant about rewilding, but now he cites it as a cornerstone of combating climate change.

Almost a century after they were wiped out in Northern Europe and the USA, wolves, for example, are returning, causing awe and delight in some, and fear and controversy in others. Intense debate followed publication of the book ‘Feral’ by journalist George Monbiot, in which he argued for widespread rewilding. Wolves are just one of the 21 key species identified by the organisation Rewilding Britain for reintroduction as part rewilding, which they believe can help save landscapes, and restore biodiversity. According to a 2018 report by the Royal Society, rewilding could also be used to lower greenhouse gas emissions and store carbon; native herbivores both produce less methane than modern cattle and maintain forests by dispersing seeds in their dung. Wild creatures work quickly and for free, offering a rapid transition of our landscape that could help mitigate some of the effects of climate change.

In the UK, although there is a growing understanding of wildlife gardening and urban rewilding – leaving areas unmown, leaving dead wood and fallen leaves for wildlife to inhabit – large scale rewilding remains contentious. We are wary of truly wild wildlife, but we understand the value of trees and greenery to human well- being. In 2013, the Woodland Trust estimated that if every household in England were provided with good access to quality green space, it could save an estimated £2.1 billion in healthcare costs. The UK is currently home to two large scale rewilding projects – the 3,500 acre Knepp estate in Sussex and the 23,000 acre Alladale Highland estate near Inverness in Scotland, both privately owned and driven by each owner’s vision.

Beavers are thriving once more after being reintroduced in the UK. Credit: Rachel Knickmeyer (CC BY-NC-ND 2.0)

Charismatic animals like the Lynx, the wildcat and the wild boar are all candidates for reintroduction in the UK, but the humble beaver is currently the key species leading the way: its incredible engineering skills create a diverse range of habitats for birds, insects, fish, small mammals and plants; slowing down water flow; preventing flooding downstream; and storing water for use locally. Beavers are native to the UK but were hunted to extinction for their highly prized fur. In 1789, the last bounty was paid in Britain for a Eurasian beaver skull; today they are thriving again – some as part of highly controlled, fenced and monitored trials and some from unregulated releases.

In 2001, the Kent Wildlife Trust with the Wildwood Trust and Natural England imported two beaver families from Norway to manage a wetland nature reserve, pioneering the use of beavers as a wildlife conservation tool in the UK. In Devon, beavers appeared (ironically) on the River Otter in 2008 and more were introduced by the Devon Wildlife Trust in 2016 to increase genetic diversity. Fenced beaver sites now exist from Knapdale in Scotland to Cornwall, and from Essex to Wales. Meanwhile, a substantial wild population of 450 beavers thrives along the Scottish Tay, probably from unregulated releases – and as a result, the beaver is now protected in Scotland.

The beaver is native to the UK and made itself quickly at home; positive effects have been reported on water catchments and biodiversity in very short periods of time. Beavers are so good at water engineering, they have been proposed as a tool for implementing the EU Water Framework Directive.

Wider relevance

Rewilding proves how good nature is at bouncing back to abundance, given the opportunity to thrive without human interference. This gives us hope for a future in which human populations could live in a more diverse environment, where the balance of nature helps mitigate our more destructive tendencies. Beavers had all but died out across Europe by the 18th century, but are returning successfully to manage waterways, ponds and whole water catchment areas. Most ponds used to be made by beavers, but are now man made. In the Devon Beaver Project site, one family of beavers made over 10 ponds in just three years, benefitting a huge array of dragonflies, birds and amphibians. The 10 clumps of frogspawn laid in 2011 increased to 370 clumps by 2018.

The reintroduction of wolves into Yellowstone Park in the US in 1995 is interesting because it shows how rewilding can work on a large scale to increase biodiversity. By the end of the 1920s almost all of the United States’ wolves were killed off, predominantly by ranchers protecting their livestock. They clung on in small populations in the northern wildernesses along the border with Canada. Within a few years, however, the Yellowstone wolf packs had made favourable impacts on the whole ecosystem through their control of the herbivore elk population. They reduced overall numbers of elk, which had grown enormous without predators, taking pressure off the grazing areas and allowing more trees to grow. Along river banks, the tree growth slowed the flow of water and reduced flooding in times of heavy rainfall. It also shaded the banks, allowing fish to flourish. The wolves are also bringing in money: wolf watching is big business and brings in an estimated four times more than elk hunting.

The finances are important because rewilding is often predicted to be a costly effort, causing the loss of productive land for food and the death of livestock by large predators. However, for a fairly small amount of money and in the right place, big changes can happen that can offer enormous benefits downstream – literally. Research by the UK’s Environment Agency suggests returning England’s water bodies to a good ecological condition could generate benefits worth £21 billion over a 37-year period. Beavers could be part of this solution, restoring wetlands, boosting water reserves and slowing down flood water. Beaver dams also act as a filter capturing pollutants such as agricultural fertilisers.

Rewilding also holds great hope for carbon capture. Healthy peat soaks up carbon as it forms over centuries. Britain has 13% of the world’s peat – but 80% is damaged and needs restoration. For every hectare, peatland absorbs the equivalent of around 3.6 tonnes of carbon dioxide per year. Maintaining vital water levels in peatland is often part of the rewilding process. Reforestation is similarly beneficial; much of the land in the UK would naturally support trees that absorb carbon – but at just 13% it has some of the lowest tree cover in Europe. For every hectare, woodland can absorb an average equivalent of around 12.8 tonnes of carbon dioxide per year.

One of the important ways in which rewilding is relevant to building a sustainable future is that it enables us to forge new relationships with the wider natural world, including top predators with whom we must share the planet if we are to survive. There is no doubt that predators will take livestock, but we can mitigate losses with planning, design and compensation. For example, Germany sees much fewer losses from herds because they keep livestock enclosed, while French farmers with sheep in the mountains complain of high losses (for which they receive compensation). Using specialist dog breeds to warn off wolves has also proven highly successful. There are some surprising benefits too: the return of the wolf also brings the return of the shepherd staying with the sheep, an ancient role that had almost disappeared from our farming environment.

Rewilding demands a cultural shift and this will be closely related to the shift needed for rapid transition in other areas. Sharing space with messy, complex nature and predators with large teeth is something to which we can and must adapt. It is worth noting that there have always been thousands of wolves on the Iberian peninsular, and although they are persecuted by people, they survive alongside a human population that is accustomed to their presence. After all, most wild creatures prefer to avoid humans; wildcats survive in Scotland because they prefer woodland, watercourses and meadows, while keeping a critical distance from villages, houses and roads. Perhaps this cultural shift could include learning from people who live close to animals that threaten them or their livelihoods, such as the Masai in East Africa, who farm livestock without eradicating lions.

Context and Background

Conservation management has failed to stem the tide of biodiversity loss. We need biodiversity to enable our food to grow, to store carbon naturally, to manage water, and for our own well-being. In Britain, the 2016 State of Nature report highlighted that between 1970 and 2013, 56% of species declined, with 40% showing strong or moderate declines. Of the nearly 8,000 species assessed using modern Red List criteria, 15% are extinct or threatened with extinction from Great Britain. A new measure that assesses how intact a country’s biodiversity is, suggests that the UK has lost significantly more nature over the long term than the global average. The index suggests that we are among the most nature-depleted countries in the world. The Living Planet Index shows a 58% global decline in populations of amphibians, fish, reptiles, mammals and birds between 1970 and 2012, varying from 36 to 38% in terrestrial and marine ecosystems to 81% in freshwater habitat.

The National Ecosystem Assessment highlighted that 30% of ecosystem services – the benefits and services nature provides society and the economy, such as clean water and flood alleviation – are in decline, and many others are impoverished compared to historical baselines. Soil degradation is estimated to be costing England and Wales £1.2 billion per year. The causes include: erosion, compaction, loss of organic matter, loss of soil biodiversity and contamination. Rewilding may be the fastest, most effective way of undoing some of this damage.

Rewilding can take a ‘passive’ form (letting land go fallow and not continuing human activity – even in the corner of a garden), ‘active’ (carrying out a range of measures including allowing species to self seed and grow, using hydration and fire but not introducing species), and ‘trophic’ (ecological restoration strategy that uses species introductions to restore top-down trophic interactions and associated trophic cascades to promote self-regulating biodiverse ecosystem). Beaver re-introduction falls into this last category, as they create a local ecosystem that is self regulating and with knock on benefits for ecosystems adjacent to it and downstream. Rewilding has been highlighted as a possible management approach in the follow-up to the first National Ecosystem Assessment. It has also been discussed as a potential solution to help mitigate flooding.

Rewilding is still contentious, but attitudes can quickly change. As recently as 2016, the globally feted naturalist David Attenborough was hesitant about Rewilding; but in 2019 he released a film called Climate Change: The Facts, listing rewilding as one of the cornerstones of combating climate change. This will undoubtedly raise the profile of the concept and help to make it more mainstream. David Attenborough’s film on the impact of plastic on wildlife is widely credited with changing public perceptions and generating unprecedented action.

Enabling factors

Most of the transitions that have occurred as a result of rewilding in the UK have been brought about because individuals with the vision and land have stepped forward at a time when government resources are tight and no immediate alternatives to the biodiversity crisis are in sight. Rewilding has happened mostly in protected parks, on large private estates, on reserves owned by conservation bodies and on private farmland. This has enabled trials to happen away from the public gaze. Many of the successful beaver releases have been unplanned and unregulated – beavers are native and therefore suited to our landscape; they flourish without our help.

The 3,500 acres of the Knepp Estate in Sussex are a good example of how private wealth coupled with enlightening risk taking can facilitate change. This estate is completely devoted to a process-led rewilding project involving free-roaming herds of cattle, horses, pigs and deer as the drivers of habitat creation. The results have been spectacular. Since its inception in 2001, numerous Red Data species like lesser spotted woodpeckers, long-eared owls and ravens have returned to Knepp and populations of common species are rocketing. Knepp Wildland is now a breeding hotspot for turtle doves and purple emperor butterflies, and boasts 2% of the UK’s entire breeding population of nightingales.

In other European countries, the government has taken a more proactive role, and several large schemes are in play across the continent, including 580,000 hectares of the Danube delta, Romania’s Southern Carpathian mountains, the Velebit mountainous region in Croatia, the Central Apennines rewilding area, and the Rhodope Mountains in Bulgaria. Much of this work led by Rewilding Europe – which is a Netherlands-based independent foundation working across Europe – has been funded with EU money. Their main tactics are undoing what is there, which is largely a one-off cost with reduced ongoing management, and attractive to funders:

  • Removing dams and dykes to restore river dynamics and reflooding;
  • Restore prey base by restocking animals for carnivores and scavengers;
  • Bring in large wild herbivores to restore natural grazing;
  • Remove fences to ‘unchain’ the beauty and the free movement of wildlife; and
  • Remove tree plantations to restore natural forest.

Scope and evidence

  • Rewilding can build resilience to the extreme weather exacerbated by climate breakdown. The UK government, Defra-funded Source to Sea project at The National Trust’s Holnicote Estate in Exmoor trialled various measures to slow flows and store water that mimic beaver activity. During the unprecedented rainfall in Somerset in winter 2013, there was no flooding in villages that regularly suffered in the past.
  • In a US study, water took three-to-four hours to travel 2.6km where there were no beaver dams. When a single, leaky beaver dam, 1.5m high, was established, it took 11 days to cover the same distance.
  • According to the Carbon Brief website, the loss of living herbivores, such as American tapirs and African and Asian forest elephants, could cause the world’s tropical forests to lose between 2% and 12% of their stored carbon.
  • Research released in 2017 estimated that, over the past 1,000 years, the replacement of wildlife with cattle in Africa has caused methane emissions to more than double from 3.4m tonnes a year to 8.9m tonnes a year.
  • George Monbiot in his book “Feral” rates the following species as suitable for rewilding projects in the UK: Beaver, Bison, Blue stag beetle, Lynx, Wild boar, Wild cat, Wolf, Capercaillie, Common crane, Dalmatian pelican, Eagle owl, Goshawk, Great bustard, Night heron, Osprey, Spoonbill, White stork, White-tailed eagle, Grey whale, European sturgeon.
  • Studies of the Pontbren Project in mid-Wales showed that shelter belts of trees kept up to 60 times the amount of water in the soil compared to pasture. The tree roots appear to create channels for water flow, allowing the soil to act as a sponge.
  • Beavers can alter the structure of the flow of water systems, create a rich resource of deadwood, create ponds that are beneficial to amphibians, alleviate downstream flooding, improve water quality and attract tourists.Plans to re-introduce the Lynx to Britain are being suggested by the Lynx UK Trust.
  • Wild boar have re-established themselves in Britain after an approximate 400-year absence. Wild boar can create tens of square metres of bare ground per week. By grubbing in the woodland floor, they increase the diversity of the plants that can grow there. They dig up bracken rhizomes, allowing tree seedlings to rise through what would otherwise be an impenetrable mat. Their wallows are a useful habitat for water-loving plants, insects and amphibians.
  • Wolf reintroduction to Scotland would save Highland estates the cost of culling the deer herd.