What is Rewilding? A Helpful Guide
Learning from nature to create self-healing ecosystems.
Rewilding is the restoration of natural processes across a connected landscape to create self-willed ecosystems which can heal themselves, creating benefits for both people and nature.
What is Rewilding?
It’s worth splitting the definition of rewilding up into two parts – people and nature. The ‘nature’ is how and why the ecosystem restoration works. The ‘people’ is how humans are an integral part of rewilding projects. Both parts are equally important.
The Origins of Rewilding
’Rewilding’ started off in the USA – it was a movement founded in huge open landscapes with little human activity. A discovery was made – reintroducing wolves had a knock-on effect on other organisms within the food web. This effect was called a ‘trophic cascade’, and this concept is important in rewilding.
Connecting up fragmented habitats across a landscape with wildlife corridors is an idea you’re probably familiar with. It sits at the heart of the American definition of rewilding – the ‘3 Cs’ model.
The 3 Cs are: Cores (protecting large areas of wild habitat), corridors (creating wildlife corridors to connect the ‘cores’) and carnivores (reintroducing missing predators). Obviously, this model isn’t as relevant in the British setting (or even most of Europe), where ‘core’ wilderness habitats are extremely degraded, and large carnivores may not be feasible to release (due to road fatalities and human development).
European Rewilding is Different
European rewilding projects typically focused on restoring landscapes with the reintroduction of large herbivores like Bison, Wild Boar (or their agricultural equivalent, the Pig), Aurochs (or functional equivalents like Water Buffalo), Beavers (and similar species like Water Voles) and wild or semi-wild Horses.
Instead of trophic cascades created by predators, in Europe, the herbivores were restoring ecosystems, making wallows and burrows, eating small trees or damming up waterways. Each of these activities created new habitats like ponds, meadows and coppices, where a whole range of biodiversity flourished.
By the late 2010s, it was becoming clear that the American definition of rewilding was increasingly irrelevant. So a team of researchers (Perino et al) published a new paper in the acclaimed journal Science, to set out a new definition for European rewilding. Their 2019 paper is one of the most highly cited journal articles in rewilding – within just a few years, it has become a touchstone for rewilders.
The only trouble is, Perino et al (2019) missed a trick. Rather than creating a catchy hook like the ‘3 Cs’, they split rewilding into ‘trophic complexity’, ‘stochastic disturbances’ and ‘dispersal’.
Yikes. So, when it comes to explaining rewilding, I take the Perino et al (2019) definition, and give it a little reimagining – a bit of spice – after all, if you want something to be widely used, you need a simple way to remember it!
The 3D’s of Rewilding – A Scientific Definition
Rewilding is defined by three principles, or ‘dimensions’, called the ‘3 Ds’.
Ecosystems are deeply-interwoven webs of diversity, and some species are more connected than others. When these species are lost, the impact on the ecosystem is a ‘trophic cascade’ – the abundance and health of connected species will be affected, which, in turn affects species linked to them, and so on. A richly-connected food web with many organisms is more stable, as it is more likely to survive the loss of any one species.
Example: Removal of Pine tree species from a landscape damages Curlew breeding success. Curlew nests are predated by Crows, which in turn are predated by Goshawks, which prefer Pine trees as nesting sites. Planting Pine trees can kick off a trophic cascade which leads to a higher Curlew population.
Rewilders like to restore food web structure by replacing missing species – i.e. reintroductions. The purpose behind any reintroduction is to restore a species (or function) lost from a habitat or area in the past. If Pine trees weren’t historically present in the landscape, then this intervention wouldn’t be considered. The ‘baseline’ used for modern rewilding is typically pre-human arrival, post-Ice Age, although this is a matter of some debate.
Sometimes, livestock are used as functional equivalents of a missing species, as they can be farmed profitably, or at least bred and managed more easily (e.g. Aurochs have a dangerous reputation, so docile cattle are used instead).
Structural diversity is also important in most landscapes – this is the variety of height and density of vegetation, the topology (variation in land height) and presence of water. Rewilders generally seek to maximise structural diversity, creating a ‘mosaic’ landscape with lots of edge habitat, which recreates natural systems – edges are usually the most biodiverse parts of an ecosystem. Some natural systems, such as peatland and saltmarsh, have low structural diversity, but rewilders elsewhere typically try to recreate our past ‘wood pasture’ landscape in which isolated trees, grassland and patches of forest are all mixed together.
Tl;dr: Food webs are complex and some species are more connected than others – reintroducing lost organisms helps restore that complexity, causing a trophic cascade which affects even distantly-connected species.
Watch our video to find out why UK rewilding is missing elephants (or read Are Humans a Keystone Species below)
Just like the American model’s ‘corridors’, we have ‘dispersal’ – the connectedness of a landscape, both in terms of contiguity – i.e. physical contact between habitats – and proximity – i.e. distance between blocks of the same habitat. Not only animals, but also plants rely on connected landscapes, as seeds are dispersed on and in the bodies of animals – ‘ectozoochory’ and ‘endozoochory’ (you don’t really need to know these terms, but they’re worth memorising to impress your mum/neighbour/cat).
Example: A Beaver may disperse along a waterway (i.e. a wildlife corridor) for a much longer distance than across open countryside. In their fur, they could be carrying the seeds of a riparian (river edge) tree like an Alder, which is deposited when they reach a new, vacant territory. When the Beavers’ parents are later killed by a Lynx, its offspring move back upriver to take their place in this newly-vacant territory, replacing their functional role as keystone ecosystem engineers.
Like diversity, dispersal increases the resilience of an ecosystem, allowing missing species to recolonise from connected habitats elsewhere. Genetic diversity is also improved by connecting habitats, and this can improve animal health and increase the likelihood of a species evolving new adaptations to survive changing environmental conditions, such as climate change. Bear in mind, too, that not all creatures walk from A to B, so habitats act more like stepping stones for airborne animals and seeds (‘proximity’ is key!).
Removal of barriers is a key principle in rewilding land management – this includes not only the removal of fences, but also of obstacles like large blocks of non-native vegetation. Non-native forestry and fields can be a barrier to movement for many species which have co-evolved with our native flora. These habitats, and human equivalents like roads and industry, also provide very little cover, which can create a psychological ‘barrier’ to movement (which is why wildlife bridges and underpasses are recommended by rewilders).
Tl;dr: Connect fragmented habitats with contiguous wildlife corridors or restore ecosystems within close proximity to similar habitats nearby – neighbouring flora and fauna will quickly move in.
Wild ecosystems are constantly changing – and many of them change quite dramatically over time, but conservationists traditionally worked to hold back change and maintain existing systems (what Benedict MacDonald refers to as ‘conservation gardening’). Rewilders embrace nature’s dynamism and use these processes to boost biodiversity and ecosystem health – a constantly-changing landscape has many more niches.
‘Ecotones’ are a key principle in rewilding – they’re the gradual shift in plant life (and associated animals etc) which you find at the edge of a habitat. A pond edge is a good example – some plants spend their whole lives underwater, while others only tolerate wet roots. If pond levels change over time (which they do in dynamic systems) and new ponds are created (think pig wallows), then ecotones are shifting and forming constantly. This is the same at the edge of habitats like woodland, which advance and recede over time. In rewilding, this movement is not only natural – it is to be encouraged – we celebrate the value it has for biodiversity, creating many new environmental niches.
Humans have, generally, reduced ‘stochastic disturbances’ – that is, unpredictable events which can cause ecosystems to be reshaped, like flooding and fire. These events are part of a healthy habitat, alongside natural processes like rivers wiggling over time, ponds silting up and trees dying. On an ideal rewilding project, natural processes are allowed to run more freely – animal carcasses are left to rot down (creating food for scavengers), rivers flood their floodplain (if this poses little danger to humans) and tree limbs rot down where they fall (returning nutrients to their roots).
Example: Pigs (or their wild relative, the Wild Boar) are a keystone agent of disturbance on rewilding projects – in fact, the most effective advice to give a new rewilder is to introduce pigs on their land, at low stocking density. They turn over the soil, killing living plants and encouraging new seeds to grow. Their wallows turn into ponds over time, they spread seeds in their trotters and dung, and this same dung is left in random patterns across the landscape, creating tiny nutrient spikes which can promote denser clumps of vegetation. Their activity is also random and seasonal, which creates a mosaic-like habitat, with varied patterns of disturbance.
Tl;dr: Wild landscapes are constantly changing, and the edge habitats or ‘ecotones’ are highest in biodiversity. Enable natural processes like tree death and river wiggling, to maximise the amount of environmental niches. Introduce pigs.
People in Rewilding Projects
People are at the heart of rewilding – a rewilded landscape is one which works for both people AND nature, not one or the other. After all, for a habitat to be protected over time, it needs to be valued by the local community, so it must serve a function. That function may be economic, recreational, aesthetic, cultural, spiritual – it really doesn’t matter which, as long as the land creates value for the local community and the landowner.
When it comes to people’s approach to rewilding, there are many different schools of thought, but one concept which I find helpful in understanding rewilding is that it is ‘open-ended’. That is, rewilders are not focused on delivering a specific habitat, or protecting it for a specific animal, but on creating a dynamic landscape which is structurally diverse, highly connected to surrounding habitats and follows natural regimes of disturbance. Another way of thinking about this is that traditional conservationists are goal-driven, focused on the destination, whereas rewilders are process-driven, focusing on the journey.
What is the Problem with Rewilding?
In the past, rewilders earned a poor reputation for excluding people from natural spaces – some projects were designed without the community in mind, or even a thought for the economics. But those projects had such a negative impact on the public perception of rewilding (a term which is still toxic in certain cultures) that modern rewilders have, understandably, put people at the heart of project design and rewilding principles. After all, a project’s success is a matter of public opinion, so it’s crucial to keep the public in mind when you’re designing a project.
The Highland Clearances were a period of time in Britain’s past when large numbers of Scottish tenant farmers were evicted, allowing their rich landlords to take control of vast swathes of the country. A similar period occurred in England – the Enclosures – in which ‘common land’ was taken out of community ownership and enclosed (typically with hedgerows), as commoners were evicted from their homes. Some critics of rewilding compare it to the Clearances, which still holds strong cultural resonance in Scotland. It is important, therefore, to address such criticisms by identifying opportunities to reverse rural depopulation, by creating jobs during the design phase of major rewilding projects – and to effectively communicate this to the local community.
People Are the Heart of Rewilding Projects
Community engagement is not just an add-on to a rewilding project – it should be at the heart of the management plan. A successful project will have community support, which will help not only with planning, logistics and local politics, but also in job creation, volunteering and economic opportunities. The most successful projects act as flywheels for rural economies; creating new jobs, attracting tourists, building political interest in the region and giving locals a sense of pride and hope in their recovering landscape.
But rewilding is more than just focusing on local communities, and, when it comes to people, there are quite a lot of different ideas about what ‘rewilding’ really means. In fact, Rewilding Europe lists a somewhat astonishing 11 different principles which they describe as the foundations of rewilding. Many of these focus on people, from ‘providing hope and purpose’ to ‘building nature-based economies’ and ‘working together’.
I prefer the more stripped-back, functional approach to integrating people and rewilding, recently suggested by Dr Paul Jepson – it’s not intended as an alternative (it’s more of a roadmap for rewilding policy), but it does concern people, and there are only 5 concepts, so it’s worth taking a look at:
- Adopt and embed a hopeful narrative of recovery
- Create nature recovery innovation zones
- Develop functional classifications of nature
- Create markets for ecosystem recovery
- Retrain officials in government agencies and NGOs
You can see how the economy is really intrinsically linked to rewilding – assigning a monetary value to nature and using this value to incentivise its protection is also right at the cutting edge of rewilding policy. This inherently leads to job creation – valuing nature allows us to create so many more jobs by bringing more money into rewilding projects. This can include anything from paying into a grant scheme when habitats are destroyed (e.g. Great Crested Newt pond grants) to putting a specific price on a ‘unit of biodiversity’, then selling the potential uplift in biodiversity generated by a rewilding project, like you would with a carbon credit (e.g. CreditNature).
This might all seem a little offputting if you are a purist – after all, as many people say – we are nature. So perhaps it is best to end, as Paul suggests, on a hopeful, holistic note – by looking at our own role in ecosystems.
Are Humans a Keystone Species?
This section concerns not just nature or just people, but a combination of the two, as any good rewilding project should. And it involves stepping back into the past, when biodiversity was so much higher than it is today. But humans still walked this island – in fact, humans could effectively be described as keystone ecosystem engineers, just like Beavers or Elephants. And we did, in fact, replace an elephant.
Straight-tusked elephants were the keystone ecosystem engineers of Britain’s past – they knocked down trees and created a Serengeti-like habitat across much of the island, now described as ‘wood pasture’. After they were wiped out, forest swept back in to dominate our landscapes, causing the biodiversity associated with wood pasture habitats to be knocked back. But eventually, humans began to manage ecosystems in a very similar way to elephants (Source: Sandom et al 2014).
We grew trees in small groves, cut down forests for firewood, opening up areas of grassland once again. We coppiced woodland, creating variable habitats with grassy meadows, bushy scrub and higher canopy forest. We also cultivated Hazel for its nuts, shoots and timber (it is excellent for charcoal production), and spread the seeds of fruit trees wherever we roamed. Our small scale agriculture created mosaics of activity across a wider, less-managed landscape, where we managed numbers of game animals by hunting for food. These activities show that humans have been, for many thousands of years, an integral part of our ecosystems.
So, humans still are a crucial part of the rewilded landscape – not just because we need community support for projects to be successful – but also because we ourselves are agents of ecosystem engineering, and we need to continue this role in the absence of the creatures we have replaced.
In most areas of the country, there are too many roads and people for Lynx to be reintroduced, so deer hunting is not just important, but an absolute necessity to bring populations down to natural levels. The same is true for forestry – in the absence of elephants, there is no ‘reset’ button on afforestation, so ecosystems will continue to get more and more wooded unless we ourselves intervene and cut down trees – natural disturbance, recreating our functional role from the past.
A Technical Point: ‘Landscape-Scale’ Rewilding
Not everyone precisely agrees on the definition of rewilding, but, thankfully, most people agree on some aspects of it. Here is one thing which didn’t make it into our definition above:
‘Landscape-scale’ – many people believe that rewilding is a landscape-scale process. But not everyone. For example, in 2022, Rewilding Britain’s ‘rewilded garden’ at the Chelsea Flower Show won ‘Best in Show’, which was the biggest rewilding news story of the year, changing the narrative around what is rewilding and what isn’t. I believe that rewilding is, to a large extent, what most people believe it is, so it’s important to take note of public sentiment.
The problem with the term ‘landscape-scale’ is that it’s impossible to define, as any definition is inherently flawed (e.g. if 500ha is rewilding, then how can 499ha not be?). Instead, the ‘dispersal’ aspect of the 3 Ds implies that a project is connected to, and set in, the context of the wider landscape and I prefer the term ‘a connected landscape’ to ‘landscape scale’. The former term embraces smaller projects, which can still benefit from rewilding principles and have an effect at a larger scale by being sensitive to their ecological context.
A year ago, I naively wrote a definition of rewilding – it was just about the first thing I wrote for howtorewild.co.uk. “How easy!” I thought, not realising how complex and controversial the subject would turn out to be. Now, a year in, I thought it was time for another go. I’ll be honest – not everyone will agree with this definition, but at least it is now grounded in a year of professional experience in the rewilding sector.
I hope that, if anyone actually reaches this far down in the article, they will finally be feeling a sense of clarity, rather than ‘I wish I’d never asked’!
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