Rewilding

The term rewilding was coined by members of the grassroots network Earth First!, first appearing in print in 1990.^[12] It was refined and grounded in a scientific context in a paper published in 1998 by conservation biologists Michael Soulé and Reed Noss.^[13] Soulé and Noss envisaged rewilding as a conservation method based on the concept of 'cores, corridors, and carnivores'.^[14] The key components of rewilding incorporate large core protected areas, keystone species, and ecological connectivity based on the theory that large predators play regulatory roles in ecosystems.^[15] '3Cs' rewilding therefore relied on protecting 'core' areas of wild land, linked together by 'corridors' allowing passage for 'carnivores' to move around the landscape and perform their functional role.^[16] The concept was developed further in 1999^[17] and Earth First co-founder, Dave Foreman, subsequently wrote a full-length book on rewilding as a conservation strategy.^[18]

Rewilding was developed as a method to preserve functional ecosystems and reduce biodiversity loss, incorporating research in island biogeography and the ecological role of large carnivores.^[19] In 1967, The Theory of Island Biogeography by Robert H. MacArthur and Edward O. Wilson established the importance of considering the size and fragmentation of wildlife conservation areas, stating that protected species and areas remained vulnerable to extinctions if populations were small and isolated.^[20] In 1987, William D. Newmark's study of extinctions in national parks in North America added weight to the theory.^[21] The publications intensified debates on conservation approaches.^[22] With the creation of the Society for Conservation Biology in 1985, conservationists began to focus on reducing habitat loss and fragmentation.^[23]

Supporters of rewilding initiatives range from individuals, small land owners, local non-governmental organizations and authorities, to national governments and international non-governmental organizations such as the International Union for Conservation of Nature. While rewilding efforts can be well regarded, the increased popularity of rewilding has generated controversy, especially in relation to large-scale projects. These have sometimes attracted criticism from academics and practicing conservationists, as well as government officials and business people.^{[24][25][26][27]} Nonetheless, a 2021 report for the launch of the UN Decade on Ecosystem Restoration, the United Nations listed rewilding as one of several restoration methods which they state should be used for ecosystem restoration of over 1 billion hectares.^[28][29]

Since its origin, the term rewilding has been used as a signifier of particular forms of ecological restoration projects that have ranged widely in scope and geographic application. In 2021 the journal Conservation Biology published a paper^[2] by 33 coauthors from around the world. Titled, 'Guiding Principles for Rewilding'. Researchers and project leaders from North America (Canada, Mexico and the United States) joined with counterparts in Europe (Denmark, France, Hungary, The Netherlands, Switzerland, and the UK), China, and South America (Chile and Colombia) to produce a unifying description, along with a set of ten guiding principles.

The group wrote, 'Commonalities in the concept of rewilding lie in its aims, whereas differences lie in the methods used, which include land protection, connectivity conservation, removing human infrastructure, and species reintroduction or taxon replacement.' Referring to the span of project types they stated, 'Rewilding now incorporates a variety of concepts, including Pleistocene megafauna replacement, taxon replacement, species reintroductions, retrobreeding, release of captive-bred animals, land abandonment, and spontaneous rewilding.' ^[2]

Empowered by a directive from the International Union for the Conservation of Nature to produce a document on rewilding that reflected a global scale inventory of underlying goals as well as practices, the group sought a 'unifying definition', producing the following:

'Rewilding is the process of rebuilding, following major human disturbance, a natural ecosystem by restoring natural processes and the complete or near complete food web at all trophic levels as a self-sustaining and resilient ecosystem with biota that would have been present had the disturbance not occurred. This will involve a paradigm shift in the relationship between humans and nature. The ultimate goal of rewilding is the restoration of functioning native ecosystems containing the full range of species at all trophic levels while reducing human control and pressures. Rewilded ecosystems should—where possible—be self-sustaining. That is, they require no or minimal management (i.e., natura naturans [nature doing what nature does]), and it is recognized that ecosystems are dynamic.'^[2]

Ten principles were developed by the group:

1. Rewilding utilizes wildlife to restore trophic interactions.
2. Rewilding employs landscape-scale planning that considers core areas, connectivity, and co-existence.
3. Rewilding focuses on the recovery of ecological processes, interactions, and conditions based on reference ecosystems.
4. Rewilding recognizes that ecosystems are dynamic and constantly changing.
5. Rewilding should anticipate the effects of climate change and where possible act as a tool to mitigate impacts.
6. Rewilding requires local engagement and support.
7. Rewilding is informed by science, traditional ecological knowledge, and other local knowledge.
8. Rewilding is adaptive and dependent on monitoring and feedback.
9. Rewilding recognizes the intrinsic value of all species and ecosystems.
10. Rewilding requires a paradigm shift in the coexistence of humans and nature.^[2]

A paper was published in 2024 that offered a "broad study of rewilding guidelines and interventions."^[30]

Rewilding can respond to both the causes and effects of climate change and has been posited as a 'natural climate solution'. Rewilding's creation of new ecosystems and restoration of existing ones can contribute to climate change mitigation and adaptation through, inter alia, carbon capture and storage, altering the Earth's albedo, natural flood management, reduction of wildfire risk, new habitat creation, and enabling or facilitating the movement of species to new, climate safe habitats, thus protecting biodiversity and maintaining functioning, climate resilient ecosystems.^{[31][32][33][34][35][36][37]}

The functional roles animals perform in ecosystems, such as grazing, nutrient cycling and seed distribution, can influence the amount of carbon that soils and (marine and terrestrial) plants capture.^[38] The carbon cycle is altered through herbivores consuming vegetation, assimilating carbon within their own biomass, and releasing carbon by respiration and defecation after digestion.^[39][40] The most beneficial effects on biogeochemical cycling and ecosystem structure are reported through rewilding large herbivore species.^[41][42] A study in a tropical forest in Guyana found that an increase in mammal species from 5 to 35 increased tree and soil carbon storage by four to five times, compared to an increase of 3.5 to four times with an increase of tree species from 10 to 70.^[43] A separate study suggested that the loss of megafauna that eat fruits may be responsible for an up to 10% reduction in carbon storage in tropical forests.^[44] Furthermore, acceleration of nutrient cycling through browsing and grazing may increase local plant productivity and thereby maintain ecosystem productivity in grassy biomes.

It is also posited that grazing and browsing reduces the risk of wildfires (which are significant contributors of GHG emissions and whose smoke can alter the planet's albedo - the Earth's ability to reflect heat from sunlight)). For example, the loss of wildebeest from the Serengeti led to an increase in un-grazed grass, leading to more frequent and intense fires, causing the grassland to turn from a carbon sink to a carbon source. When disease management practices restored the wildebeest population, the Serengeti returned to a carbon sink state.^[38][45]

Rewilding's effect on albedo is not only through potential reduction of smoke from wildfires but also through the effects of grazing itself. By reducing woody cover through browsing and trampling, large herbivores expose more ground surface and thus increase the albedo effect, reducing local surface temperatures and creating a net surface cooling effect during spring and autumn.

Other forms of ecological restoration as part of rewilding can also assist with mitigating climate change. For example, reforestation, afforestation and peat re-wetting can all contribute to carbon sequestration. ^[46] While carbon sequestration could allow carbon offsetting and carbon trading as a way to monetize rewilding there has been concern that the highly speculative nature of carbon markets encourages 'land grabbing' (i.e., buying large areas of land) and 'greenwashing' from natural capital investors and multi-national companies.^[47]

Passive rewilding (also referred to as ecological rewilding)^[48] aims to restore natural ecosystem processes via minimal or the total withdrawal of direct human management of the landscape.^[49][50][51]

Active rewilding is an umbrella term used to describe a range of rewilding approaches all of which involve human intervention. These might include species reintroductions or translocations and/or habitat engineering and the removal of man-made structures.^[52][49][53]

Pleistocene rewilding is the (re)introduction of extant Pleistocene megafauna, or the close ecological equivalents of extinct megafauna, to restore ecosystem function. Advocates of the approach maintain that ecosystems where species evolved in response to Pleistocene megafauna but now lack large mammals may be in danger of collapse.^[54][55] Meanwhile critics argue that it is unrealistic to assume that ecological communities today are functionally similar to their state 10,000 years ago.

Trophic rewilding is an ecological restoration strategy focused on restoring trophic interactions and complexity (specifically top-down and associated trophic cascades where a top consumer/predator controls the primary consumer population) through species (re)introductions, in order to promote self-regulating, biodiverse ecosystems.^[56][57]

Ecosystem engineers are ‘organisms that demonstrably modify the structure of their habitats’. ^[58] Examples of ecosystem engineers in rewilding include beaver, elephants, bison, elk, cattle (as analogues for the extinct aurochs) and pigs (as analogues for wild boar).^{[59][60][61][62]}

A keystone species is a species that has a disproportionately large effect on its environment relative to its abundance.

Apex predators may be required in rewilding projects to ensure that browsing and grazing animals are kept from over-breeding/over-feeding thereby destroying vegetation complexity^[19] and exceeding the ecological carrying capacity of the rewilding area, as was seen in the mass-starvations which occurred at the Oostvaardersplassen rewilding project in the Netherlands.^[63] While predators play an important role in ecosystems, however, there is debate regarding the extent to which the control of prey populations is due to direct predation or a more indirect influence of predators (see Ecology of fear).^[64] For example, it is thought that wildebeest populations in the Serengeti are primarily controlled by food constraints despite the presence of many predators.^[65]

Some national governments and officials within multilateral agencies such as the United Nations, express the view that 'excessive' rewilding, such as large rigorously enforced protected areas where no extraction activities are allowed, can be too restrictive on people's ability to earn sustainable livelihoods.^[26][27] The alternative view is that increasing ecotourism can provide employment.^[66]

Rewilding has been criticized by animal rights scholars, such as Dale Jamieson, who argues that 'most cases of rewilding or reintroducing are likely to involve conflicts between the satisfaction of human preferences and the welfare of nonhuman animals'.^[67] Erica von Essen and Michael Allen, using Donaldson and Kymlicka's political animal categories framework, assert that wildness standards imposed on animals are arbitrary and inconsistent with the premise that wild animals should be granted sovereignty over the territories that they inhabit and the right to make decisions about their own lives. To resolve this, von Essen and Allen contend that rewilding needs to shift towards full alignment with mainstream conservation and welcome full sovereignty, or instead take full responsibility for the care of animals who have been reintroduced.^[68] Ole Martin Moen argues that rewilding projects should be brought to an end because they unnecessarily increase wild animal suffering and are expensive, and the funds could be better spent elsewhere.^[69]

The environmental historian Dolly Jørgensen argues that rewilding, as it currently exists, 'seeks to erase human history and involvement with the land and flora and fauna. Such an attempted split between nature and culture may prove unproductive and even harmful.' She calls for rewilding to be more inclusive to combat this.^[70] Jonathan Prior and Kim J. Ward challenge Jørgensen's criticism and provide examples of rewilding programs which 'have been developed and governed within the understanding that human and non-human world are inextricably entangled'.^[71]

Some farmers have been critical of rewilding for 'abandoning productive farmland when the world's population is growing'.^[72] Farmers have also attacked plans to reintroduce the lynx in the United Kingdom because of fears that reintroduction will lead to an increase in sheep predation.^[73]

Some conservationists have expressed concern that rewilding 'could replace the traditional protection of rare species on small nature reserves', which could potentially lead to an increase in habitat fragmentation and species loss.^[72] David Nogués-Bravo and Carsten Rahbek assert that the benefits of rewilding lack evidence and that such programs may inadvertently lead to 'de-wilding', through the extinction of local and global species. They also contend that rewilding programs may draw funding away from 'more scientifically supported conservation projects'.^[74]

Both grassroots groups and major international conservation organizations have incorporated rewilding into projects to protect and restore large-scale core wilderness areas, corridors (or connectivity) between them, and apex predators, carnivores, or keystone species. Projects include: the Yellowstone to Yukon Conservation Initiative in North America (also known as Y2Y), the European Green Belt (built along the former Iron Curtain), transboundary projects (including those in southern Africa funded by the Peace Parks Foundation), community-conservation projects (such as the wildlife conservancies of Namibia and Kenya), and projects organized around ecological restoration (including Gondwana Link, regrowing native bush in a hotspot of endemism in southwest Australia, and the Area de Conservacion Guanacaste, restoring dry tropical forest and rainforest in Costa Rica).^[75]

In North America, a major project aims to restore the prairie grasslands of the Great Plains.^[76] The American Prairie is reintroducing bison on private land in the Missouri Breaks region of north-central Montana, with the goal of creating a prairie preserve larger than Yellowstone National Park.^{[76]: 187–199}

Dam removal has led to the restoration of many river systems in the Pacific Northwest in an effort to restore salmon populations specifically but with other species in mind. As stated in an article on environmental law:

'These dam removals provide perhaps the best example of large-scale environmental remediation in the twenty-first century. [...] The result has been to put into motion ongoing rehabilitation efforts in four distinct river basins: the Elwha and White Salmon in Washington and the Sandy and Rogue in Oregon'.^[77]

In 1997, Douglas and Kris Tompkins created 'The Conservation Land Trust Argentina' with the goal of transforming the Iberá Wetlands. In 2018, thanks to a team of conservationists and scientists, and a donation of 195,094 ha (482,090 acres) of land by Kris Tompkins, an area was converted into a National Park, and jaguar (a species that had been extinct in the region for seven decades), anteaters and giant otters were reintroduced. A spin-off of the Tompkins Foundation, Rewilding Argentina, is an organization dedicated to the restoration of El Impenetrable National Park, in Chaco, Patagonia Park, in Santa Cruz, and the Patagonian coastal area in the province of Chubut, in addition to Iberá National Park.^[78]

The red-rumped agouti and the brown howler monkey were reintroduced in Tijuca National Park (Rio de Janeiro state, Brazil), between 2010 and 2017 with the goal of restoring seed dispersal.^[79] Prior to the reintroductions, the national park did not have large or intermediate -sized seed dispersers, the increased dispersal of tree seeds following the reintroductions therefore had a significant effect on forest regeneration in the park.^[79] This is significant since the Tijuca National Park is part of heavily fragmented Atlantic Forest and there is potential to restore many more seed dispersal interactions if seed dispersing mammals and birds are reintroduced to forest patches where the tree species diversity remains high.^[80]

Colonisation has had a significant impact on Australia's native flora and fauna, and the introduction of red foxes and cats has devastated many of the smaller ground-dwelling mammals. The island state of Tasmania has become an important location for rewilding efforts because, as an island, it is easier to remove feral cat populations and manage other invasive species. The reintroduction and management of the Tasmanian devil in this state, and dingoes on the mainland, is being trialed in an effort to contain introduced predators, as well as over-populations of kangaroos.^[81]

WWF-Australia runs a program called 'Rewilding Australia' whose projects include restoring the platypus in the Royal National Park, south of Sydney, eastern quolls in the Booderee National Park in Jervis Bay and at Silver Plains in Tasmania, and brush-tailed bettongs in the Marna Banggara project on the Yorke Peninsula in South Australia.^[82] Other projects around the country include:^[81]

• Barrington Wildlife Sanctuary, NSW
• Mongo Valley, NSW
• Bungador Stoney Rises Nature Reserve, Victoria
• Mount Zero-Taravale Sanctuary, Queensland
• Dirk Hartog Island National Park, Western Australia
• Marna Banggara, SA
• Clarke Island/Lungtalanana, Tasmania

In 2011, the 'Rewilding Europe' initiative was established with the aim of rewilding one million hectares of land in ten areas including the western Iberian Peninsula, Velebit, the Carpathians and the Danube delta by 2020.^[83] The project considers reintroductions of species that are still present in Europe such as the Iberian lynx, Eurasian lynx, grey wolf, European jackal, brown bear, chamois, Iberian ibex, European bison, red deer, griffon vulture, cinereous vulture, Egyptian vulture, great white pelican and horned viper, along with primitive domestic horse and cattle breeds as proxies for the extinct tarpan and aurochs (the wild ancestors of domestic cattle) respectively. Since 2012, Rewilding Europe has been heavily involved in the Tauros Programme, which seeks to create a breed of cattle that resembles the aurochs by selectively breeding existing breeds of cattle.^[84] Projects also employ domestic water buffalo as a grazing analogue for the extinct European water buffalo.^[85]

European Wildlife, established in 2008, advocates the establishment of a European Centre of Biodiversity at the German–Austrian–Czech borders, and the Chernobyl exclusion zone in Ukraine.

Der Biosphärenpark Wienerwald was created in Austria in 2003 with 37 kernzonen (core zones) covering a total of 5,400 ha designated free from human interference.^[86]

Rewilding Britain, a charity founded in 2015, aims to promote rewilding in Britain and is a leading advocate of rewilding.^[87] Rewilding Britain has laid down 'five principles of rewilding' which it expects to be followed by affiliated rewilding projects.^[88][89] These are to support people and nature together, to 'let nature lead', to create resilient local economies, to 'work at nature's scale', and to secure benefits for the long-term.

Celtic Reptile and Amphibian is a limited company established in 2020, with the aim of reintroducing extinct species of reptile and amphibian (such as the European pond turtle,^[90] moor frog, agile frog,^[91] common tree frog and pool frog)^[92][93] to Britain. Success has already been achieved with the captive breeding of the moor frog.^[94][95] A reintroduction trial of the European pond turtle to its historic, Holocene range in the East Anglian Fens, Brecks and Broads has been initiated, with support from the University of Cambridge.^[96]

In 2020, nature writer Melissa Harrison reported a significant increase in attitudes supportive of rewilding among the British public, with plans recently approved for the release of European bison, Eurasian elk, and great bustard in England, along with calls to rewild as much as 20% of the land in East Anglia, and even return apex predators such as the Eurasian lynx, brown bear, and grey wolf.^[97][98][59] More recently, academic work on rewilding in England has highlighted that support for rewilding is by no means universal. As in other countries, rewilding in England remains controversial to the extent that some of its more ambitious aims are being 'domesticated' both in a proactive attempt to make it less controversial and in reactive response to previous controversy.^[99] Projects may also refer to their activity using terminology other than 'rewilding', possibly for political and diplomatic reasons, taking account of local sentiment or possible opposition. Examples include 'Sanctuary Nature Recovery Programme' (at Broughton) and 'nature restoration project', the preferred term used by the Cambrian Wildwood project, an area aspiring to encompass 7,000 acres in Wales.^[100]

Notable rewilding sites include:

• Knepp Wildland. The 3,500 acre (1,400 hectare)^[101] Knepp Castle estate in West Sussex was the first major pioneer of rewilding in England, and started that land-management policy there in 2001^[102][103] on land formerly used as dairy farmland.^[101] Rare species including common nightingale, turtle doves, peregrine falcons and purple emperor butterflies are now breeding at Knepp and populations of more common species are increasing.^[104] In 2019 a pair of white storks built a nest in an oak tree at Knepp. The storks were part of a group imported from Poland as a result of a programme to reintroduce the species to England run by the Roy Dennis Wildlife Foundation which has overseen reintroductions of other bird species to the UK.^[105]
• Broughton Hall Estate, Yorkshire. In 2021, approximately 1,100 acres (a third of the estate)^[106] was devoted to rewilding with advice from Prof. Alastair Driver of Rewilding Britain.^[107]
• Mapperton Estate, Dorset. In 2021, a 200 acre farm (one of the five farms comprising the estate) began the process of rewilding.^[108]
• Alladale Wilderness Reserve, Sutherland, Scotland. This 23,000 acre estate hosts many wildlife species and engages in rewilding projects such as peatland and forest restoration, captive breeding of the Scottish wildcat, and reintroduction of the red squirrel. Visitors can engage in outdoor recreation and education programs.^[109]

The British radio drama series The Archers featured rewilding areas in storylines in 2019 and 2020.^[110][111]

In the 1980s, analogue species (Konik ponies, Heck cattle and red deer) were introduced to the Oostvaardersplassen nature reserve, an area covering over 56 square kilometres (22 sq mi), in order to (re)create a grassland ecology by keeping the landscape open by naturalistic grazing.^[112][113] This approach followed Vera's 'wood-pasture hypothesis' that grazing animals played a significant role in shaping European landscapes before the Neolithic period. Though not explicitly referred to as rewilding, many of the project's intentions were in line with those of rewilding. The case of the Oostvaardersplassen is considered controversial due to the lack of predators, and its management can be seen as having to contend with conflicting ideas regarding nature.^[114]

• Climate change mitigation effects of rewilding
• Environmental restoration
• Feral, a 2013 book about rewilding
• Great Green Wall (Africa)
• Involuntary park
• Natural landscape
• Permaculture
• Sea rewilding
• Species reintroduction
• Urban prairie
• Urban reforestation
• Wildlife management

• van der Land, Hans and Poortinga, Gerben (1986). Natuurbos in Nederland: een uitdaging, Instituut voor Natuurbeschermingseducatie. ISBN 90-70168-09-x (in Dutch)
• Foreman, Dave (2004). Rewilding North America: A Vision for Conservation in the 21st Century, Island Press. ISBN 978-1-55963-061-0
• Fraser, Caroline (2010). Rewilding the World: Dispatches from the Conservation Revolution, Picador. ISBN 978-0-312-65541-9
• Hawkins, Convery, Carver & Beyers, eds. (2023). Routledge Handbook of Rewilding, Routledge.
• Jepson, Paul and Blythe, Cain (2022). Rewilding: The Radical New Science of Ecological Recovery (The Illustrated Edition), The MIT Press.
• MacKinnon, James Bernard (2013). The Once and Future World: Nature As It Was, As It Is, As It Could Be, Houghton Mifflin Harcourt. ISBN 978-0-544-10305-4
• Monbiot, George (2013). Feral: Rewilding the Land, the Sea, and Human Life, Penguin. ISBN 978-0-14-197558-0
• Monbiot, George (2022). Regenesis: Feeding the World without Devouring the Planet, Penguin Books. ISBN 978-0-14-313596-8
• Louys, Julien et al. (2014). "Rewilding the tropics, and other conservation translocations strategies in the tropical Asia-Pacific region". doi:10.1002/ece3.1287
• Root-Bernstein, Meredith et al. (2017) "Rewilding South America: Ten key questions". doi:10.1016/j.pecon.2017.09.007
• Pereira, Henrique M., & Navarro, Laetitia (2015). Rewilding European Landscapes, Springer. ISBN 978-3-319-12038-6
• Pettorelli, Durant & du Troit, eds. (2019). Rewilding, Cambridge University Press.
• Tree, Isabella (2018), Wilding: The Return of Nature to a British Farm, Picador, ISBN 978-1-5098-0511-2
• Wilson, Edward Osborne (2017). Half-Earth: Our Planet's Fight for Life, Liveright (W.W. Norton). ISBN 978-1-63149-252-5
• Wright, Susan (2018). SCOTLAND: A Rewilding Journey, Wild Media Foundation. ISBN 978-0-9568423-3-6
• Thulin, Carl-Gustaf, & Röcklinsberg, Helena (2020). "Ethical Considerations for Wildlife Reintroductions and Rewilding". doi:10.3389/fvets.2020.00163

• American Prairie Reserve
• Area de Conservacion Guanacaste, Costa Rica
• European Green Belt
• European Wildlife - European Centre of Biodiversity
• Gondwana Link
• Heal Rewilding
• Highlands Rewilding
• Lewa Wildlife Conservancy
• Peace Parks Foundation
• Pleistocene Park
• Rewilding Britain
• Rewilding Europe
• Rewilding Australia
• Rewilding Institute
• Self-willed land
• Scotland: The Big Picture
• Terai Arc Landscape Project (WWF)
• Wildland Network UK
• Wildlands Network N. America (formerly Wildlands project)
• Wisentgrazing-project, Holland

• Book on experimental methods to rewild forests with grazers and dead and decaying wood
• an docu-film about the reintroduction of wild horses 15 years after
• Rewilding the World: Dispatches from the Conservation Revolution
• "Rewilding the World: A Bright Spot for Biodiversity"
• Rewilding and Biodiversity: Complementary Goals for Continental Conservation, Michael Soulé & Reed Noss, Wild Earth, Wildlands Project Fall 1998
• Stolzenburg, William (2006). "Where the Wild Things Were". Conservation in Practice. 7 (1): 28–34. doi:10.1111/j.1526-4629.2006.tb00148.x. Archived from the original on 21 November 2008. Retrieved 12 April 2010.
• "For more wonder, rewild the world", George Monbiot's July 2013 TED talk
• Bengal Tiger relocated to Sariska from Ranthambore | Times of India