Introduction

The term ‘rewilding’ is gaining ground in discussions about nature conservation and the future of agricultural landscapes. Rewilding is based on the idea that as human societies have developed and expanded geographically, ‘wild’ landscapes have become fragmented and domesticated. The ambition of rewilding is to turn the tide: it aims to give land back to nature and change the management of ecosystems for them to become more resilient and autonomous. Ultimately, rewilders argue, this will contribute to the restoration of global biodiversity, may strengthen other ecosystem functions such as flood protection and carbon sequestration, and changes how humans can experience nature. In fostering these goals, rewilders often draw inspiration from the species and ecological processes that landscapes have lost throughout human history.

The concept of rewilding emerged in the 1990s from the field of conservation biology but has gained wider resonance in recent years, now finding support from a diverse group of stakeholders, including environmental activists, philanthropists, journalists, corporations, farmers, policy makers and private foundations, who sometimes interpret the term differently. Influenced by these actors, debate about rewilding has evolved from a focus on the reintroduction of extinct species or their relatives in large nature reserves to a wider discussion about the future of nature, agriculture and rural landscapes in the Anthropocene.

This explainer introduces the concept of rewilding. It compares different rewilding strategies, explores their relationship with agriculture, and discusses major areas of contestation.

1. What is rewilding?

1.1 Origin and meaning

Although rewilding has only recently captured public attention, the concept is several decades old. The term was introduced in the early 1990s by a group of North American conservation biologists including Michael Soulé and Reed Noss who developed the first rewilding strategy (the 3C approach, see box 1)1. This early work on rewilding presented some of the core principles and ideas that still resonate within the rewilding community. It also sparked controversy and some of the critiques that were raised then are still central to the rewilding debate today. It is important to note that rewilding is a heterogeneous and evolving movement. While rewilding is often criticised for views that are present in the work of its early champions, rewilders today do not always see their own approaches reflected in these discussions.

Soulé and Noss introduce rewilding as an idea in contrast with mainstream biodiversity conservation. Reflecting on past decades of biodiversity conservation in North America, they conclude that the conservation movement has both failed to confront the root causes of biodiversity loss and lost sight of the ‘intrinsic’ and ‘spiritual’ value of ‘wilderness’ (note that wilderness is a loaded and contested term – see section 1.3). Biodiversity loss in North America, they point out, has a long history that started with the arrival of the first humans at the end of the Pleistocene; North America has gradually lost most of its ‘wilderness’ and with it many of the species that made biodiversity thrive. To break this trend, they argue, it would be necessary for large segments of land in North America to be ‘rewilded’.

Central to Soulé and Noss’ rewilding vision is the principle of reintroducing species such as the wolf, which went extinct in large parts of North America. The idea here is that the loss of so-called ‘keystone species’ (see box 1) can have a large impact on the overall functioning of the ecosystem and result in substantial biodiversity losses. Their reintroduction, on the other hand, could lead biodiversity to self-restore. Soulé and Noss refer here to the case of Yellowstone National Park where the reintroduction of wolves is thought to have made the park more biodiverse1. Their ultimate ambition, however, is to reintroduce a wider range of large mammals that would help biodiversity regain the complexity it had during the Pleistocene.

The principle of reintroducing species has become a main characteristic of rewilding initiatives and builds upon a particular perspective on conservation that was pioneered by Soulé and Noss. Mainstream biodiversity conservation, they argue, follows a compositionalist model of first mapping an area’s species composition and then protecting a set of smaller ‘hotspots’ that together represent this biodiversity1^,7. This approach reduces ‘wilderness’ to a set of target species and habitats that require protection. However, it overlooks the conditions and processes that need to be in place to sustain biodiversity in the long run. Rewilding, instead, embodies a functionalist approach to ecosystems7. It views them as dynamically evolving sets of interacting species that cover all kinds of functions such as grazing, predating and scavenging1^,2^,7,8. The (re)introduction of species with particular functions in this complex may change how the ecosystem functions and set it on a pathway of increased species richness, more resilience and reduced dependence on human management9.

Rewilding covers an increasingly diverse range of context-specific strategies (section 2) that are characterised by this functionalist approach. Most of them combine intentional reintroductions of a few species with a subsequent hands-off attitude to the ecosystem. Many rewilders today, however, are critical of Soulé and Noss’ focus on the Pleistocene as an ideal for today’s landscapes. Their focus tends to be less on re-creating any particular historical baseline and more on how the functional complexity of current ecosystems could be enhanced to foster biodiversity as well as ecosystem services such as carbon sequestration or flood protection10^,11.

1.2 Controversy

Rewilding has sparked controversy, in particular over the idea of reintroducing large mammals and over its implications for rural and indigenous communities. In a 2005 article12, several US conservation biologists (including Soulé) argued for the introduction of cheetahs, elephants and lions in North American landscapes on the grounds that they would act as functional analogues for similar species that went extinct at the end of the Pleistocene. Some advocates of species reintroductions go a step further, hoping to introduce not just functional analogues but – one day – the extinct species themselves. Ecologists at the Pleistocene Park in Siberia, for instance, aim to bring a genetically engineered version of the mammoth ‘back’ to today’s tundra landscapes (see box 2).

Critics argue that reintroduction plans rely on oversimplified views of how such species will interact with their environment6^,15^,16. Reintroducing large mammals that went (locally) extinct millennia ago can cause human-wildlife conflicts (see box 3) and impact on ecosystems in very similar ways as so-called invasive species: they may wreak havoc and devastate existing populations of native species. For some rewilders these ecosystem-changing effects are precisely why they think the species should be reintroduced1^,17. Other rewilders however are critical of reintroducing large carnivores and functional analogues of extinct species or else call for a careful assessment of the potential implications for ecosystem functioning.

Another main critique of rewilding is that it is predicated on the view that ‘wilderness’ is a place devoid of humans. Some critics see rewilding as continuing a long history of eco-imperialist and colonialist conservation activities. Triggered by conceptions of wilderness that exclude people, these often went hand-in-hand with the denigration and displacement of rural and indigenous communities. Others point out that even if rewilding would not give rise to new displacements, it might still be used to legitimise existing inequalities and undermines conservation agendas that centre on both social and ecological justice.

Critics here tend to refer to rewilding’s preoccupation with historical baselines: a posited time point in the past that marks an ecosystem’s ‘original state’. Attempts at restoring nature to its original, ‘pristine’ state, they point out, generally ignore the fact that very few, if any, landscapes are unshaped by human presence. This includes those landscapes that are categorised as ‘wild’ today, many of which have gained their ‘wild’ character – at least in part – from how they have been managed by indigenous peoples.

Some rewilding initiatives have abandoned the notion of a historical baseline (because of their possible societal or ecological implications – see section 2.1.2). Various of these explicitly state that they view people as part of nature and seek to develop approaches that work for both nature and local communities34^,35.

1.3 Rewilding our imagination

For many in the rewilding movement, rewilding encompasses much more than just biodiversity conservation. Some argue that the concept is underpinned by a belief that humanity has gone too far in regulating nature and domesticating the planet. The desire to discipline and control our world, they point out, has not only caused landscapes to become predictable (the British writer and activist George Monbiot for instance speaks of ‘ecological boredom’36) but extends its influence into how we live, think, feel and experience the world around us.

An important distinction here is that between ‘wilderness’ and ‘wildness’. Rewilders such as Soulé and Noss define rewilding as being first and foremost about the protection of wilderness. Others, however, place more emphasis on an idea of wildness. Whereas wilderness is a physical state of a landscape (uninhabited, not affected by human interventions), wildness indicates a quality (someone or something being undisciplined and/or resisting control). The spiritual goal of returning ‘wildness’ to life is not limited to how we manage landscapes but extends into other domains37 (it can for example be seen in the increasing popularity of microadventures, wild swimming and wild fermentation). Rewilders who centre on wildness rather than wilderness also tend to have less hardline views about the need for rewilded areas to be protected from human presence.

More generally, the value rewilders attach to wildness is evident in their emphasis on nature’s power and its resilience to restore itself when humans stop trying to subject it to their wishes. They tend to be critical of mainstream conservation for assuming nature to be first and foremost vulnerable and in need of human protection because this, in so doing, risks creating a self-fulfilling prophecy: by constraining species and habitats to protect what is currently there, it undermines nature’s power to restore itself.

2. Rewilding today

Rewilding has evolved beyond the 3C approach into a family of strategies7^,38 that vary by geographical context. The majority of current rewilding projects are in North America and Europe, but attention to rewilding has also recently spread to other parts of the world including South Africa39^,40 and China41,42 (see box 4).

Commonly used concepts include Pleistocene rewilding, Holocene rewilding, trophic rewilding and passive rewilding. These are different, but overlapping, perspectives that have evolved over time. The former two (section 2.1) refer to different historical baseline scenarios that some rewilders aim to restore. Trophic and passive rewilding (2.2) do not indicate such an end goal but refer to mechanisms through which rewilding, as an open-ended process, could take place.

2.1 A question of baselines

The historical baseline concept plays an important role in the rewilding debate. A major difference between rewilding strategies lies in how they address the baseline question. While this might seem a purely theoretical matter for conservation ecologists, it gives rise to different ways of managing the landscape, and this in turn to very different species and a different relationship to other land uses including farming.

At around the time Pleistocene rewilding emerged in North America in the 1990s, conservation biologists in Europe developed similar ideas but focused on the Holocene (2.2.1). In recent years, some rewilders have abandoned explicit historical baselines in favour of more future-oriented approaches (2.1.2 and 2.2.2). The discussion about these baselines shows how rewilding can radically challenge but also align with existing priorities for both biodiversity conservation and rural development.

At a fundamental level, rewilding foregrounds the question of baselines in conservation: it challenges conventional conservation’s preoccupation with protecting what biodiversity is currently there (1.1) and instead shifts the baseline either back to a distant past (2.1.1) or forward to the Anthropocene (2.1.2)43.

2.1.1 Pleistocene and Holocene baselines

The geographical origins of Pleistocene and Holocene rewilding (see box 5) explain some of the differences between them. Perhaps the most pronounced difference is that Pleistocene rewilding (emerged in North America) revolves around the reintroduction of large predators whereas Holocene rewilding (developed in Europe) focuses on the reintroduction of large herbivores.

Box 5: Pleistocene and Holocene rewilding              Pleistocene and Holocene rewilding are two models that aspire to restore landscapes and their biodiversity to different points in time: the Pleistocene – the period lasting from 2.5 million years ago until about 11,700 years before today – or the Holocene – lasting from the end of the Pleistocene till today. Pleistocene rewilding refers to perspectives that adopt the Pleistocene as the reference point for the rewilding of today’s landscapes. Projects generally assume a large scale (say >100,000 ha) or aim to expand to this scale and are generally intended for geographical contexts with low population densities and little competition with agricultural land use (e.g. Siberia and parts of the US).   YouTube video 1: Pleistocene Park: Born to rewild. Currently covering around 2000 ha of land, the Pleistocene Park in Siberia aims to recreate the steppes of the Pleistocene in large parts of the Arctic by introducing large herbivores. This approach would limit the release of carbon dioxide and methane from thawing permafrost (which is contested). The project is also controversial for its ambition to reintroduce the mammoth by genetic engineering. Holocene rewilding takes as its baseline the period after the last ice age when agriculture started to take off and, as a result, the human population grew rapidly. It is heavily influenced by the ideas of the Dutch conservation biologist Frans Vera who argues44 that in the absence of large-scale, intensive land uses, European lowlands would not, as often thought, develop into a dense, closed-canopy forest, but rather into an open, park-like landscape maintained by large populations of herbivores. While this perspective is contested45, it has influenced several rewilding projects including the Knepp Wildland project in the UK and the Oostvaardersplassen in the Netherlands (see figure 1). Holocene rewilding projects typically cover a relatively small amount of land (~1,000-10,000 ha) and revolve around the introduction of large herbivores such as the Konik horse (a primitive horse species) and Heck cattle. Image Figure 1 – Two examples of Holocene rewilding. On the left: Longhorn cattle at the Knepp Wildland estate (image by Tomline43 via Flickr). On the right: Heck cattle in the Oostvaardersplassen (image by Peter Galvin via Flickr).

A notable difference between these two contexts is that the average European landscape has – and has had for a long time – a much higher population density than the average North American landscape. Large predators have been extinct for centuries in most of Europe and their reintroduction can be difficult, for example because typical conservation areas are much smaller than the territories required by such animals, resulting in a higher risk of human-wildlife conflicts than in North America.

In addition, most landscapes in Europe have long been intensively cultivated. Understandings of what European landscapes should look like and which species should be conserved are strongly influenced by how these landscapes have evolved under human influence. For instance, there is a long history in Europe of farmland bird conservation, mainly based on preventing human-made landscapes, such as extensively managed pastures and heathland, from either turning into forests or being lost to more intensive land uses. European rewilders’ focus on large grazers aligns to a great extent with ambitions to preserve these human-made landscapes and associated species46^,47. North American rewilders, on the other hand, call for large predator reintroductions in contexts where large herbivores are sometimes considered to inhibit tree growth and thereby habitat diversification1^,48.

2.1.2 Anthropocene rewilding

Various recent rewilding perspectives consider how humans and wildlife could live together in new ways and in new landscapes during the Anthropocene49. These ‘Anthropocene rewilding’ perspectives criticise conservation for its ‘backward looking’ attitude and see rewilding as, first and foremost, a future-oriented endeavour. Their criticisms consist of two main areas:

First, critics raise ecological and historical questions: Which period counts as ‘original’ and why? How do we know what nature looked like before humans arrived? Does it matter that any act of ‘restoration’ is itself a human intervention? The US-based science writer Emma Marris, for example, points out that attempts at restoring ecosystems to a past state often ruin new forms of nature that can be valuable in their own right50. Marris, who has written critically about rewilding but whose books are also a source of inspiration for today’s rewilding community, emphasises that ideas about what a landscape ‘originally’ looked like tend to go hand-in-hand with strong, dogmatic views about which species, ecosystems or landscape features are worth preserving and which are not. This is for example visible in the common tendency to classify species as desirable ‘native species’ and inferior ‘invasive species’ (with the latter often being weeded out to prevent them from ‘crowding out’ the former)50.

Second, critics of historical baselines in rewilding mention the socio-political implications of restoring nature to a pre-human baseline. The desire to restore such baselines, they argue, tends to be predicated on the flawed and romanticised ideal of ‘pristine wilderness’. Ostensibly ‘pristine’ landscapes, however, have generally been managed by local communities for centuries or longer. Historically, the objective of preserving wilderness has led to evictions and the erasure of (indigenous) peoples’ histories from their ancestral lands51​​​​​​​. The concern here is that rewilding (or at least its pre-human baseline variants) revives the exact principles and assumptions that the conservation movement needs to renounce to confront its history of elitism, colonialism and eco-imperialism7​​​​​​​^,51​​​​​​​^,52​​​​​​​^,53.

The critique on baselines has caused the vocabulary of the rewilding debate to change: Pleistocene and Holocene rewilding have now by and large made place for concepts such as trophic and passive rewilding (2.2) that do not prescribe a desired baseline scenario. There are, however, important differences between future-oriented Anthropocene rewilding initiatives: some of them endorse a ‘people inclusive’ perspective that seeks, in the words of their proponents, pragmatic win-wins for nature and local communities54​​​​​​​^,55​​​​​​​. This part of the rewilding movement tends to advocate for a patchwork approach where rewilding principles are applied in different ways and at different scales depending on the context. Others, however, see ecological merit in the creation of ‘novel ecosystems’43​​​​​​​^,56 but stick to the goal of establishing large areas that are (largely) inaccessible to humans. Finally, while Anthropocene rewilding abandons the ideal of a baseline scenario, this does not mean that it disregards ‘history’ altogether. Initiatives may, for example, be found to restore the course of a river or to reintroduce a species that went locally extinct but without the overarching objective of resurrecting ecosystems of the past.

2.2 Trophic and passive rewilding: two different perspectives

Two main approaches to rewilding today are trophic rewilding and passive rewilding:

Trophic rewilding draws heavily on the original 3C approach but does not target a particular historical baseline2​​​​​​​^,57​​​​​​​^,58​​​​​​​ and is silent on the question of scale. Fundamentally, it is defined by the principle of restoring trophic interactions. North American rewilding strategies tend to focus on top-down trophic interactions (i.e. the influence of large carnivores cascading through the food chain), whereas European strategies generally adopt a bottom-up perspective (i.e. nutrient availability at lower trophic levels such as that of plants influencing population sizes at the level of herbivores and above)43​​​​​​​. While the North American focus on large carnivores and European focus on large herbivores might seem contradictory, both are predicated on the restoration of trophic interactions and can be seen as synergetic43. In focusing on restoring ecosystems’ trophic complexity, trophic rewilding encompasses all forms of rewilding that involve reintroductions (including Pleistocene and Holocene rewilding)8​​​​​​​^,59.

Reintroductions are a deliberate human intervention, often with lasting impacts on the ecosystem. In trophic rewilding, reintroductions tend to be accompanied by other interventions such as fencing, which, although controversial, are in some cases a legal requirement8​​​​​​​^,60​​​​​​​^,61​​​​​​​^,62. So far, most trophic rewilding initiatives are based in Europe where, typically, they take place within a patchwork of other land uses and in regions with a high population density. Fencing here reduces the risk of road kills and human-wildlife conflicts60​​​​​​​^,63​​​​​​​. These sites are generally small (1,000-10,000 ha) compared to the original 3C approach’s vision of interconnected cores. Some rewilding projects such as the Oostvaardersplassen in the Netherlands have been criticised on animal welfare grounds for ‘trapping’ large herbivore populations in a small area where natural feed is scarce64​​​​​​​. Other commentators of the Oostvaardersplassen approach, however, point out that the ethical questions here are complex as the reintroduced grazers blur the boundaries between ‘wild’ and ‘domesticated’ animals65​​​​​​​. Opponents express little concern over the fate of ‘wild animals’ (who often live under a welfare-limiting regime of ‘proactive culling’), but seem to impose welfare standards for livestock and companion animals to the de-domesticated/semi-wild animals in the Oostvaardersplassen65.

Sometimes trophic rewilding happens without active reintroductions59. Examples of this include the spontaneous comeback of the beaver in the US and of the wolf in Europe. There is some overlap here between trophic rewilding and passive rewilding.

Passive rewilding is the spontaneous rewilding of ecosystems when land is left to its own devices57​​​​​​​^,66​​. It can be applied intentionally, but the concept also includes cases when (agricultural) land is abandoned. Arguably, as a result of farmland abandonment in Eastern Europe and some other world regions67​​​​​​​^,68​​​​​​​^,69​​​​​​​, unintentional passive rewilding currently covers far more land than do other forms of rewilding. Passive rewilding involves no or very little human intervention (e.g. sometimes fences are removed rather than installed) and does not specify an explicitly desired historical baseline scenario to which the landscape should revert or include deliberate reintroductions of keystone species. Intentional passive rewilding typically revolves around the understanding that processes such as globalisation, trade, climate change and land use change have altered ecosystems irreversibly. Rather than eradicating ‘invasive species’, passive rewilders tend to view that their place in these ‘novel ecosystems’ should be accepted and valued43.

3. How does all this relate to agriculture?

Rewilding projects tend to take place either on farmland or on land dedicated to forestry or nature conservation. If rewilding were to scale up, much of its increased land cover may come from (abandoned) farmland. Agriculture is the greatest user of land in the world: to rewild these lands, whether by seeking to restore them to some past state or to allow them to evolve into some new state of wildness, would require a significant share of agricultural land being taken out of production or at least be used in a very different way (see figure 2).

Figure 2: Global land use since 10,000 BC. Figure by Our World in Data based on data from Ellis, E.C., Beusen, AH., & Goldewijk, K.K. (2020)70.

There is strong opposition to the idea of rewilding from some farming communities, based on the assumption that rewilding requires a substantial area of agricultural land to be taken out of production. However, this is not what all rewilders argue for.

Two differing perspectives seem to be emerging within the rewilding movement: The first is a more radical form of rewilding that aims to create a large network of protected areas isolated from society and which tends to find itself in tension with current agricultural landscapes. The second is more conciliatory and seeks to foster rewilding goals wherever possible and in balance with other socio-economic priorities including farming.

The radical form particularly resonates with (Pleistocene) rewilding strategies that call for the reintroduction of large predators and the creation of large ‘core’ areas for nature that are inaccessible for humans. From an overall land use perspective, this form of rewilding goes hand-in-hand with the principle of land sparing (see figure 3 and our explainer on the land sparing-sharing continuum). The idea here is to free up a maximum amount of land for nature by shrinking food production’s land use through intensifying agricultural production.

Image

Figure 3: A schematic representation of what land sparing and land sharing approaches to rewilding could look like. Figure by TABLE using icons from the Noun Project.

The second perspective calls for a mosaic of approaches. In some areas, it encourages the creation of larger core areas including the reintroduction of large carnivores. Proponents of this approach have for example advocated for the return of diverse woodlands on deer hunting estates in Scotland, combined with the reintroduction of the lynx and a (partial) transition from livestock production on marginal lands to arable production on a smaller area of land (see YouTube video 2). However, they also tend to emphasise the need for such initiatives to find the support of local communities71. In more densely populated areas or existing arable farming landscapes, rewilding principles might be applied at much smaller scales and in synergy with farming. An example is the Knepp Wildland project in the UK: An arable farm turned into a nature conservation project that still produces some (albeit very limited) agricultural output through the culling of the hardy cattle that were introduced to manage the landscape.

YouTube video 2: A video by Rewilding Britain showing what the rewilding of an upland valley in the UK could look like and which shows a transition from sheep farming to arable farming at a smaller scale.

These conciliatory approaches have found support among some farmer groups. They tend to promote the view that farmers can be both producers of food and caretakers of the natural environment. This in essence aligns with a land sharing model for landscapes based on the principle of integrating agricultural production and nature conservation on the same piece of land (see figure 3).

This part of the rewilding movement finds itself aligned with the regenerative farming and agroecology movements (see our interactive visual which explores the similarities and differences between the agroecology and regenerative movement). This is not only the result of their synergistic approach to farming and rewilding, but also because of more fundamental similarities between rewilding (both its conciliatory and radical flavours) and these movements. First, rewilding shares the prefix ‘re’ with regenerative farming (as well as with ‘reforestation’ and ‘ecological restoration’). Both contain the aspiration to return some of the species, ecological processes, or landscape features that were lost in the development of intensive (agricultural) land uses. Second, rewilding’s principle of ecosystem restoration resonates with agroecology and regenerative agriculture’s emphasis on ‘healthy’ soils and of ‘working with’ nature. Each of these movements promotes the idea that certain functions of soil, or ecosystems can and should be restored by changing our management of the land from merely constraining species to ‘using life to manage life’37​​​​​​​. This vision is visible both in rewilding’s focus on keystone species and agroecology and regenerative agriculture’s emphasis on soil microbes, fungi and root systems72​​​​​​​^,73​​​​​​​^,74​​​​​​​^,75. Those approaches are distinct from ones that aim to control ecosystems through repression alone (e.g. by culling deer or chemical pest control). A further similarity between regenerative agriculture and some versions of rewilding lies in the role they see for large herbivores in managing the landscape76.

Whether rewilding requires an existing landscape to change significantly does not necessarily follow from how radical the chosen strategy is. For example, the implementation of a radical strategy may require very little to change in the case of an existing ‘fortress conservation’ project (a project built on the belief that the protection of nature needs to happen in isolation of people). On the other hand, the implementation of a conciliatory strategy could lead a landscape that is dominated by agricultural monocultures to change drastically. Depending on the strategy adopted, rewilding can accordingly be found to both challenge or align with many actors’ pre-existing interests. Partly as a result of this capacity to encompass a range of (sometimes conflicting) viewpoints, rewilding has found support from a diverse set of actors.

Most rewilding visions are positioned somewhere between the radical and conciliatory end points. Various of the more radical projects, for example, seek some involvement of local people (e.g. by hiring them as park managers or tourist guides). Some of the relatively conciliatory versions, on the other hand, call for integrated approaches to farming and rewilding in one place but for strong reductions in human presence and farming elsewhere. Monbiot, for instance, argues for a patchwork rewilding of 10% of Britain’s terrestrial land, for an important part by removing sheep and deer from marginal lands in the uplands and by further reducing agricultural land use through farm-free production systems such as cellular agriculture36​​​​​​​^,77​​​​​​​^36,77. This approach would have major implications for the UK’s agricultural production, trade, diets and consumption. For Monbiot (and others), rewilding goes hand-in-hand with policies aimed at achieving substantial population-level dietary changes, especially major reductions in meat and dairy consumption36​​​​​​​^,78.

4. Nature needs half

The radical perspective on rewilding finds strong support among some environmentalists and rich landowners who aim to create large refuges for threatened species. A leading and controversial example is the Nature Needs Half campaign, which argues that to preserve 85% of the world’s remaining biodiversity, a large network of protected areas should cover at least half of the Earth’s surface by 203079​​​​​​​^,80​​​​​​​. Introduced in 2016 by Edward Wilson79​​​​​​​ (one of the pioneers of the island biodiversity theory) and championed by leading conservation biologists from the US including Noss81, this half Earth perspective essentially applies the 3C approach globally.

Critics of the half Earth perspective have interpreted it as a proposal for separating society from nature on a global level. This, they point out, will have widespread negative consequences for people and in particular for the poorest, most exploited and most disenfranchised communities. They call instead for conservation approaches that see ‘people as part of nature’ and that foster ‘socio-ecological justice’82​​​​​​​^,83​​​​​​​. In addition to concerns that rewilding might provide a rationale for new displacements of rural and indigenous peoples, critics also fear that rewilding’s relative ‘blindness’ to socio-political issues renders it incapable of identifying, challenging and ultimately reversing existing power dynamics. A case in point here is the current interest of rich elites in rewilding their private estates (in Scotland this process has been dubbed the ‘rise of the Green Lairds’84​​​​​​​ – see also billionaire-funded initiatives elsewhere such as Rewilding Argentina)85. Local communities may have no say in such processes and positive narratives about rewilding’s implications for nature might ‘greenwash’ the structural inequalities underlying land ownership models83​​​​​​​. That said, the half Earth movement is heterogeneous and many of its members hold the view that actions to safeguard the world’s biodiversity can and should pursue social justice at the same time (see e.g. the half-Earth project’s statement on justice and inclusion).

Underlying this discussion are different analyses of issues and root causes. Coming as they do from a background in conservation biology, some rewilders and half Earth advocates understand the problem to be a loss of ‘wilderness’ and the species it sustains, which is fundamentally driven by the expansion of human societies and their demands. Critics coming from a social justice perspective see the ecological crisis as inextricably linked to the social problems we face as a species, since both ultimately originate from structural inequalities and an economy predicated on perpetual growth. The debate between these two groups should nevertheless not be reduced to a mere ‘population growth versus overconsumption’ debate. Both groups emphasize the importance of reducing resource-intensive lifestyles, but the latter group has a stronger and more explicit awareness of the unequal global power dynamics that underlie the issue and takes a more explicitly political approach. For example, parts of both groups are aligned in their view that global reductions in intensive livestock production and associated consumption of animal-based foods could help free up substantial areas of land for nature.

It is unlikely that the critique that rewilding reinforces existing power relations applies equally across all strategies and projects. Some of the more ‘human-inclusive’ rewilding initiatives explicitly aim for a more democratic approach. The Court Farm initiative in Dorset, for example, was enabled by a loan from a philanthropist but is operated by a local conservation charity that involves local communities in the decision making. More generally, versions of rewilding that lie at the land-sharing end of the spectrum find themselves aligned with agroecological approaches that emphasise the importance of social and ecological justice.

5. Different futures for nature

The premise of rewilding is that it will free up land for nature and that its overall impact on biodiversity will be positive. Very little research has studied this claim empirically – in part because there are still few practical examples of rewilding8. While rewilding is likely to mean ‘more space for more species’, the various strategies and visions for agriculture they relate to can result in different futures for nature and biodiversity.

The application of more radical or conciliatory rewilding approaches can have important implications for what a landscape will look like and the species that will inhabit it. Such differences include the possible presence of agriculture (or other land uses) in the landscape, the elimination of ‘invasive species’ (likely in, say, Holocene or Pleistocene rewilding but unlikely in passive rewilding) and the extent to which large herbivore populations, which affect tree growth, are present.

The rewilding movement encompasses a diversity of views on the future for landscapes. Perspectives here are not only influenced by ecological considerations but also by a combination of current land use patterns and pre-existing ideal conceptions of nature, rooted in culture and history. Finding their origins in Pleistocene rewilding, the more radical rewilding perspectives tend to echo the ideal of sublime, desolate wilderness that has influenced US culture through the work of writers such as Henry David Thoreau and John Muir86​​​​​​​^,87​​​​​​​. These perspectives have found the support of a range of wealthy elites both in North America and elsewhere (e.g. South Africa, Argentina or Scotland) that aim to rewild their private estates with limited involvement of local communities. Conciliatory rewilding perspectives which seek synergies with agroecological and regenerative farming approaches resonate with visions of pastoral Arcadia and the Biblical garden of Eden, in which humans and nature harmoniously coexist86​​​​​​​^,87​​​​​​​^,88​​​​​​​^,89. These approaches have predominantly appeared in more densely populated contexts in Europe where rewilding takes place at a smaller scale and amidst competing land uses.

In terms of rewilding’s ecological merits, the premise is that keystone species reintroductions will lead to more diverse habitats and species. Many rewilders, however, agree that this requires a context-specific approach where species are not introduced blindly but instead, their influence on the landscape, habitat formation and populations of current and potentially new species is considered9​​​​​​​. In some cases, rewilding initiatives can lead to a loss of particular species in the landscape (and are met with opposition from conservationists who want to protect such species). In existing conservation areas, rewilding might result in increases in some species and reductions in others. For example, a few studies have found that introducing large herbivores to a nature reserve increases plant diversity but reduces arthropod diversity90​​​​​​​^,91​​​​​​​. Another possibility is that a rewilding project’s initial biodiversity successes (e.g. the return of some target bird species) may be temporary92​​​​​​​⁹². For example, a build-up of phosphorus fertiliser in abandoned farmland can cause the landscape to become gradually dominated by a few plant species (e.g. juncus effusus)93​​​​​​​^,94​​​​​​​^,95​​​​​​​^,96.

On a landscape level, the extent to which rewilding takes place amidst human land uses may influence which species will flourish. Research on the effects of land-sparing and land-sharing approaches on biodiversity has shown that land-sparing landscapes generally support a greater diversity of specialist species, which can thrive only in specific habitats, whereas land-sharing landscapes tend to support mostly generalist species that can live in many habitat types97​​​​​​​^,98​​​​​​​. This finding is important because most of the world’s threatened species are specialists (see our explainer about the land sparing-sharing continuum). A caveat here is that agricultural lands, depending on how they are managed, can constitute an important habitat area for some specialist species. Wetland species such as the Black-tailed Godwit, for example, have a preference for semi-flooded, herb-rich grasslands that are minimally grazed during their nesting season99​​​​​​​^,100.

If rewilding were to be applied globally, which strategy dominates and the extent to which rewilding leans towards land sparing or sharing could have real consequences for the kinds of biodiversity that will flourish and for which species the world may lose.

6. Conclusions

Rewilding encompasses a range of strategies that share the goals of creating more space for nature and allowing it to restore ‘autonomously’. Most of them centre on the notion of ‘keystone species’, whose reintroduction would return a full range of ecological functions to the landscape.

In recent years, rewilding has drawn the interest and support of diverse stakeholders, particularly from North America and Europe. While rewilding has evolved differently in these regions, the global rewilding movement is united in its goal to stop global biodiversity loss and kickstart its restoration. Shared among them is also a desire to create a ‘wilder’ Earth where humans will be able to experience nature – and more diverse natures – more frequently and in new, more diverse ways.

If rewilding were to scale up, this would have major implications for how rural landscapes develop. The exact consequences for nature, agriculture and rural populations would, however, differ according to which of the various rewilding strategies dominates within a given context.

Rewilding strategies differ in their position on agriculture. Radical perspectives (including Pleistocene rewilding) broadly align with principles of land sparing and associated agricultural intensification. They find themselves in partial tension with agroecology and regenerative farming agendas. Strategies that are more accommodating of human presence find themselves aligned with agroecological and regenerative farming practices.

Originating as it does in the field of conservation biology, rewilding has hitherto lacked a clear socio-economic focus or agenda. Critics question rewilding’s implications for rural populations and indigenous peoples, given some rewilders’ preoccupation with ‘pristine wilderness’. Pleistocene rewilding and the half-Earth perspective are, in particular, criticised for advocating a separation between nature and human land uses. These more radical approaches to rewilding have found most support among wealthy landowners who operate large nature reserves in relatively sparsely populated areas (e.g. North America, South Africa, Argentina or parts of Scotland). More pragmatic forms of rewilding have emerged in more densely populated areas in Europe. These tend to seek synergies between rewilding and rural development and find themselves largely aligned with the agroecology and regenerative farming movements. These latter strategies can give rise to landscapes that contain more generalist species and provide less habitat to the world’s most fragile species.

Definitions of rewilding

Rewilding is a broad concept that emerged in the 1990s in the field of conservation biology and which has evolved in recent years to encompass a range of visions on nature and the management of ecosystems. Rewilding revolves around the understanding that ‘nature’ has become marginalised throughout human history. The ambition of rewilding is to turn the tide: it aims to give land back to nature and change the management of ecosystems for them to become more resilient and autonomous. In doing so, rewilding aims to kickstart the restoration of global biodiversity and strengthen ecosystem functions such as flood protection and carbon sequestration. An important underlying objective for many rewilders is to create a ‘wilder’ Earth where humans will be able to experience nature more frequently and in new, more diverse ways. Common rewilding strategies include trophic rewilding (the restoration of complex trophic interactions between species kickstarted by the reintroduction of keystone species such as large carnivores or large herbivores) and passive rewilding (the spontaneous rewilding of ecosystems when land is left to its own devices). Rewilding is a contested term. Debate centers on the implications of rewilding for food production and for rural and indigenous communities. An important topic of discussion concerns the extent to which rewilding is compatible with farming and whether its large-scale adoption would require a substantial downscaling of agricultural land use. Further topics of debate include the goal of some rewilders to restore landscapes to a pre-human baseline (see Pleistocene and Holocene rewilding) and various proposals to reintroduce large carnivores (e.g. wolves and tigers) in places where these went extinct. While rewilders today do not always see their own approaches reflected in these discussions, critics of rewilding are in favour of alternative visions that seek to restore nature and biodiversity through approaches that they see to be more clearly based on the principle of social justice.

Holocene rewilding is a rewilding strategy that takes the early to late Holocene (after the emergence of agriculture and before the industrial revolution) as its historical baseline for ecosystems. Whereas Pleistocene rewilding is associated primarily with the reintroduction of large carnivores, Holocene rewilding emphasises the role of large herbivores such as (ancient) cattle and horse species in managing the landscape. Holocene rewilding revolves around the wood-pasture hypothesis by the Dutch conservation biologist Frans Vera, which states that after the last ice age, European lowlands will have developed into semi-open pastures dotted with large solitary trees and small patches of trees and shrubs, kept open by large herbivores. This hypothesis is contested.

Passive rewilding refers to the spontaneous rewilding of ecosystems when land is left to its own devices. It can be applied intentionally, but the concept also includes cases when (agricultural) land is abandoned. Arguably, as a result of farmland abandonment in Eastern Europe and some other world regions, unintentional passive rewilding currently covers far more land than do other forms of rewilding. Passive rewilding involves no or very little human intervention and does not specify an explicitly desired historical baseline scenario to which the landscape should revert, or include deliberate reintroductions of keystone species.

Pleistocene rewilding is a rewilding strategy that takes the Pleistocene (the period from roughly 2.5 million years ago until about 11,700 years ago) as its historical baseline for ecosystems. While Pleistocene rewilders draw inspiration from the species and functional complexity of ecosystems during the Pleistocene, they do not necessarily aim to recreate the exact same ecosystems as existed during this period. Pleistocene rewilding is associated with the reintroduction of large carnivores such as the wolf. It has mainly been promoted in North America and has its origins in the 3C-approach: an approach to rewilding that calls for the establishment of large cores (nature conservation areas where human interference is minimised), corridors that allow wildlife to travel between core areas, and the reintroduction of large carnivores. Pleistocene rewilding is contested as – depending on the context – it could give rise to human-wildlife conflicts and has been criticised for being based on views and principles that could lead to the marginalisation and displacement of rural and indigenous communities.

Trophic rewilding is defined by the principle of restoring trophic interactions. These include predator-prey relationships in the food chain but also other processes such as scavenging or decaying that constitute nutrient flows in the ecosystem. Trophic rewilding aims for the diversification and increasing complexity of the web of such interactions. As such trophic rewilding is a broad concept that encompasses other rewilding strategies such as Pleistocene and Holocene rewilding. However, unlike these more specific strategies trophic rewilding does not seek to restore nature to a particular historical baseline and is silent on questions about scale.

Related concepts

Conservation biology is often described as a mission-driven discipline and is a field of study concerned with the protection and maintenance of the earth’s biodiversity. Research in conservation biology draws on other disciplines including ecology, biology and the social sciences and humanities.

De-extinction refers to the use of back breeding, cloning or genetic engineering to bring an extinct species ‘back to life’ or develop a species that is similar to it in terms of, for example, appearance and behaviour. The ambition of de-extinction initiatives is often for these species to be reintroduced and for them to contribute to the rewilding of landscapes.

Ecological restoration refers to the principle of restoring something, for example a landscape or an ecosystem, based on ecological principles, processes or methods. An example of this can be the restoration of an deforested area by allowing forest to re-emerge through various forest succession stages rather than planting a mixture of the plant species that used to be present before the area was deforested. Ecological restoration can take place as part of a rewilding strategy. Rewilding strategies, however, tend to come with more specific ideas about which species should be present or (re)introduced and a clear overall vision about particular processes in the ecosystem that should be encouraged.

Ecosystem restoration refers to the process of restoring aspects of an ecosystem that have been lost through for example the reintroduction of species or management practices to regain lost landscape features. The restoration of an ecosystem can be an outcome of rewilding. Not all rewilding strategies, however, aim to restore (aspects of) ecosystems that have been lost. Some rewilding strategies are more future oriented.

Fortress conservation is an approach to conservation that is based on the belief that goals for nature conservation are best achieved by the establishment of (large) nature reserves that are (largely) inaccessible to humans. Fortress conservation is controversial both for its assumption that the protection of biodiversity would be best served by creating isolated conservation areas and because it can go hand-in-hand with – and has historically done so – harms to rural and indigenous communities (e.g. displacements or even ethnic cleansing) who inhabit areas that are or were turned into fortress conservation projects.

Keystone species are species that have a disproportionate influence on the functioning of an ecosystem relative to their numerical abundance and in comparison with other species such that their loss or (re)introduction in an ecosystem can affect the ecosystem’s overall functioning. Species such as the wolf, elephant or beaver are often considered to be keystone species but keystone species are not necessarily mammals. For example, woodpeckers or particular starfish species are sometimes included in this category.

Novel ecosystems are ecosystems that as a result of human influences have changed to the extent that the biotic elements (living things such as animals, plants or bacteria) and abiotic elements (non-living things such as water, rocks and air) are almost entirely different from what they have been in a historical state of the ecosystem. Novel ecosystems are defined relative to a past state of the ecosystem and the role humans have had in changing it. While this means that what does and does not count as a novel ecosystem is context dependent and subject to interpretation, the concept is generally used to refer to ecosystems that have experienced substantial human-induced changes in recent history (say the past two centuries). Examples of ecosystems that are often considered as ‘novel’ are deforested primary forests and areas that have a very different species composition due to the introduction and spread of non-native species resulting from human activity such as intercontinental trade.

Reforestation refers to the spontaneous or intentional return of trees in an area that has lost its forest cover either as a result of deforestation by humans or in other ways such as wildfire or drought.

Please navigate to the glossary for more definitions and related content.

Suggested citation

Fraanje, W., & Garnett, T. (2022). Rewilding and its implications for agriculture. TABLE Explainer Series. TABLE, University of Oxford, Swedish University of Agricultural Sciences and Wageningen University and Research.

Written by

• Walter Fraanje, TABLE, Wageningen University and Research
• Tara Garnett, TABLE director, University of Oxford

This piece benefited from edits and comments from various TABLE team members including Helen Breewood, Trish Fisher and Wendy Jenkins.

Reviewed by

• Professor Emeritus Jozef Keulartz, Philosophy Group, Wageningen University and Research
• Professor Emeritus Kris van Koppen, Environmental Policy Group, Wageningen University and Research  
• Professor Jamie Lorimer, School of Geography and the Environment, University of Oxford
• Rebecca Wrigley, Chief Executive, Rewilding Britain

We also had exchanges with another reviewer whose comments were very useful, but who wishes to remain anonymous.

Note that reviewing and advising do not constitute an endorsement, and the named reviewers should not be understood to agree with everything in the piece. Final editorial decisions, including any remaining inaccuracies and errors, are the sole responsibility of TABLE.

Funded by

• The Oxford Martin School
• The Swedish University of Agricultural Sciences
• Wageningen University and Research
• The Wellcome Trust through the Livestock, Environment and People (LEAP) project (grant number 205212/Z/16/Z)
• The Quadrature Climate Foundation