With all the discussion on rewilding it is worth posing the question ‘what is rewilding?’ It means different things to different people, not least as it can refer to landscapes and to people. This article concentrates on rewilding landscapes.

Google ‘rewilding’, and we are given the definition “restore (an area of land) to its natural uncultivated state (used especially with reference to the reintroduction of species of wild animal that have been driven out or exterminated)”.  This fits well with my own thoughts: that rewilding means restoring natural habitats and restoring native species, by reintroductions or natural colonisation. This does of course raise a bunch of questions. For example, what is the natural state of any particular piece of land, what is our reference point? And do we need to go all the way, make the land completely wild with all the native animals present, before we consider an activity rewilding?

I will come back to these questions, but first I want to look at a couple of other definitions. The Rewilding Institute in North America uses the idea of the ‘Three Cs’, that is Cores, Corridors and Carnivores. Large predators are seen as driving ecosystems by their interactions with other species, and the way their effects cascade through the whole ecosystem – the so-called ‘trophic cascade’. For example in Yellowstone, the return of the wolf has changed the behaviour of deer and elk in several ways. One of these is that the herbivores spend much less time at watering places. This has allowed tree regeneration to occur along river banks, along with increased flowers, insects and birds. Beavers have then returned, creating conditions for more fish, benefiting otters, and many other mammals, reptiles and amphibians. The wolves also compete with coyote, and this impact on coyote has led to an increase in rodent populations, which in turn has benefited birds of prey, weasels, foxes and badgers. And the carrion left by wolves has provided more food for ravens and eagles. And most interestingly, the bear population has increased as the bears benefit from the hunting skills of the wolves, and from the increase in berries growing with the reduced herbivore browsing.

That’s one example. The other two Cs follow on from the value of the large carnivores: in order to form viable populations, they require large core areas of wilderness, and they need safe corridors connecting these core areas so they can migrate safely without coming into conflict with humans. Here in Britain, we are some way from making space for large carnivores, but the principles of core areas and corridors are important concepts we can apply. The need for large predators is evident from an ecological standpoint when you look at deer populations in some areas, though the social realities make this an awkward proposition currently.

The definition in Wikipedia introduces another important element of rewilding. It states that “rewilding is large-scale conservation aimed at restoring and protecting natural processes and core wilderness areas, providing connectivity between such areas, and protecting or reintroducing apex predators and keystone species”.

The restoration of natural processes, mentioned here, is generally considered to be a crucial element of rewilding. Wilderness areas flourish without the human management input associated with agriculture, forestry and nature conservation as generally practiced in Britain: in conventional nature conservation, an area is managed intensively to favour a particular species or habitat, using some form of farming or forestry practice, for example ‘conservation grazing’ with livestock. Restoring an area to a wild state therefore includes restoring the natural processes – with dynamics such as the relationship between large predators, wild herbivores and the vegetation structure left to their own devices.

With natural processes dominating, you would think that the question raised earlier – what is the natural state of a particular landscape? – doesn’t need to be answered. All we do is leave the area unmanaged, and it will develop into its natural state. But this ignores the effect of the starting point for the land. If it is a sitka spruce plantation or infested with rhododendron or Japanese knotweed, none of which are native plants and all of which spread readily, the land is unlikely to develop into anything remotely like a natural area, nor be the sort of habitat favourable to wild animals.

Similar questions arise even without such plants in the landscape. An open landscape remote from native woodland cover might eventually become woodland, but it could take centuries and its development will be influenced by what is happening on neighbouring land. Also, since large herbivores are a natural part of the landscape, we cannot claim that natural processes are operating without wild grazing animals, and for that matter without other animals such as beaver who play such an integral role in the dynamics of rivers. And if we have herbivores, their impact on the landscape will not be natural without the presence of large predators.

These factors all imply some initial habitat restoration could be required, along with the reintroduction of large herbivores and other animals, and ongoing management of herbivores while the carnivores are absent. And these in turn imply making decisions on what are the natural components and state of the landscape. In this context, some discussion centres on two specific questions about what counts as rewilding: the habitat restoration method, for example whether woodland is established through natural colonisation or planting; and the intensity of grazing and whether the herbivores are wild or domestic.

With regards to grazing, there are strong arguments against using domestic livestock as proxies for wild herbivores. Regulations around welfare and health demand regular interventions. As well as the extra costs involved, there are some ecological consequences. For example, welfare concerns might require winter feeding which in turn provides an unnatural boost to the herbivore population with consequent impacts on the vegetation. On the other hand, cattle and horses graze differently to deer and are proxies to the now extinct aurochs and tarpan – without these, the fauna is incomplete.

There is also debate on whether the tarpan was native to Britain in the current interglacial period; and whether the Exmoor pony might be near enough a direct descendent of the tarpan. In Europe, cattle have been ‘back-bred’ to produce primitive aurochs type breeds. Of course, there are debates about how close to the aurochs these are. And there are issues around having the cattle recognised as wild animals: currently they are not, and are subject to EU regulations on domestic livestock.

With regards to habitat restoration through tree planting, some commentators argue that tree planting does not count as rewilding. The main argument is that the decisions on species and structure of a planted woodland are necessarily too prescriptive, too much like landscape design, and therefore against the principles of letting natural processes drive the development of the landscape. On the other hand, a decision to not plant an area is just as much a management decision. In my view, thorough research on the natural vegetation cover of an area achievable through pollen records in soil cores – for most places in Britain this is some form of woodland – provides the best guidance on establishing the initial conditions for then letting natural processes take over. In many instances, natural regeneration will be the most suitable way to restore woodland cover. But where the land is remote from native trees as seed sources, planting will be desirable.

The two themes running through the definitions of rewilding are ‘restoration’ and ‘natural processes’. Although different people emphasise one or the other of these, they are both important and predominate at different stages along the rewilding time-line. I suggest that the dominance of natural processes, without any human intervention, can be seen as a kind of holy grail. And that rewilding is the journey to that holy grail, it is the process of restoring land so that natural processes can dominate. How far we can proceed on the journey might be limited by biological or social factors. Today in Britain, for example, the reintroduction of wolf is biologically feasible, but from a social perspective there are some obstacles to seeing this happen for a while.

In one example, on part of the Knepp Estate in the well-wooded county of Sussex, the initial restoration activity following the last arable harvest was simply to introduce some feral herbivores. From then on, natural processes have been allowed to take over, with an ongoing intervention of removing a proportion of herbivores each year. In contrast, at Carrifran, a remote and treeless upland site, the removal of sheep and goats from the landscape was followed by tree planting and deer culling to establish an ecologically restored area where natural processes can now dominate.

I don’t think the debates will ever subside, and I will continue to find them fascinating. I also believe it’s a good thing if ‘rewilding’ or ‘wildland’ escape from any formal definition. What we need is more of it, whatever it is, happening on the ground, using a variety of methodologies. We need more facts and experience to inform the debates. More importantly, we need some wild nature to repair the damage humans have wrought on this planet over the last few hundred years and for our own spirits to be enriched by living with the wild.

I will conclude with another definition of rewilding that seems to cover the landscape and people, which will provide a nice link to the theme of another article about rewilding ourselves: “to return to a more wild or self-willed state; the process of undoing domestication”.