Rewilding Part 1: Defining a Target

Rewilding. A bit of a hot topic in conservation at the moment, with advocates such as George Monbiot pushing the practice into the public eye. Even this very website has had several rewilding articles of late. But, despite all of the publicity the subject has gathered, very few people have truly considered the positives and the negatives. Almost everyone I know that is aware of the concept of rewilding is in support, but most of those people have only thought about the good side of it. Over my next few articles I hope to cover several aspects of rewilding, and allow you to make up your own mind. Like all good stories, I’ll start at the beginning and try to answer the simplest question: what is it?

People use different definitions of rewilding depending on their audience. To some, the main focus of rewilding is the reintroduction of megafauna (large herbivores and carnivores) to areas within their former range, and they tend to tout this as the definition. In the UK we love the idea of wolves, bears and lynx stomping across the landscape (Scotland being most people’s preferred location for this), and we like the idea of correcting the damage of our ancestors; there is a lot of support for rewilding on that basis alone.

This isn’t, however, why scientists proposed rewilding in the first place and as a definition it is somewhat lacking. By releasing such animals, it is thought that ecological and evolutionary processes will be restored and our ecosystems will be healthier. For example, if we introduce wolves to the UK then they will (it is thought) bring down our burgeoning deer population and as a result promote forest regrowth, much as the reintroduction of wolves to Yellowstone has done (there’s a very popular Monbiot narrated Youtube video on this very subject).

So, the actual definition of rewilding can be written fairly simply as reintroductions to restore ecosystem function (or words to that effect). The specifics of the rewilding process are where it gets contentious. Firstly, we use the word reintroduction, but how long ago must a species have gone extinct in order for us to consider it a candidate for rewilding? In the UK we tend to talk about introducing wolves, lynx, beavers and bears, but these animals were wiped out hundreds of years apart. If we introduce one then do we need to introduce the others to fully restore the ecosystem or do we just aim for some sort of remnant of what we once had? If we decide to introduce all of these then we are effectively setting the clock back a millennium.

That raises more questions. What makes the extinctions of the last 100, or even 1000 years more important than those that occurred before that? Absolutely nothing. 1000 years is an arbitrary target. A target that we could achieve, yes, but there is no real reason to set it there. If the aim is to restore ecosystems untouched by humans then we have to go back far further and carry out something known as “Pleistocene Rewilding”. Here, the aim becomes to introduce animals that were present before modern Homo sapiens, animals that were around at the time of the mammoth. Clearly, some of these animals will be globally extinct and supporters of Pleistocene rewilding propose that these are replaced with proxies. So for example the mammoth can be replaced with the African elephant.

Setting a defined baseline target, as in Pleistocene rewilding, actually raises more issues than it settles. Yes, we now have a date and a hypothetical list of species (and proxies) that we could introduce, but do we introduce them all or just a few? What is our selection process? Do we introduce plants as well as animals? What if some of them are well known pests in other countries?

On top of this, Pleistocene rewilding means we’re resetting the evolutionary clock to a pre-human time. Will the introduced animals be able to survive in our new, anthropogenic world? What happens to species that we’ve embraced in the modern day but were introduced since the Pleistocene, (such as the fallow deer)? Are these species (which in some cases are considered native) actively removed or left alone? What if the species we’ve chosen to introduce went extinct naturally and not because of humans: do they also get a second chance? These questions all need answers that are, sadly, not very forthcoming.

Most followers of rewilding do not support Pleistocene rewilding because they see it as unnecessary and unfeasible. The thing is, unless we aim for pre-human rewilding, we do end up where we were 3 paragraphs ago, just arbitrarily choosing species to introduce. This isn’t such a problem for places such as the USA where they have other baselines to choose from, like the arrival of Columbus in 1492, but we in the UK have no such option. Rewilding supporters are currently lacking an answer to the “how far back” question.

Those against rewilding are loving the lack of a coherent target. Combined with the fact that the restoration of ecological function is rather theoretical and circular (you have to actually introduce the animals to find out what effect they will have once introduced), and the limited knowledge around the survival abilities of certain species, there are strong arguments against rewilding based releases.

These arguments haven’t put people off trying. There are plenty of examples of rewilding across the world. As I mentioned at the beginning, this is the first of a series of articles I’m going to publish, and next time I’m going to talk about real life cases of rewilding. I’ve touched on Yellowstone and the UK beaver introductions here, but there are several other examples that are perhaps more interesting, not least because of how they have chosen to address the problems I’ve briefly mentioned!


For more on UK rewilding, visit:

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Emilie Brignall

Emilie Brignall

Oxford biology grad, trying to find my place in the world.
Emilie Brignall

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1 Response

  1. 18th April 2016

    […] to focus on? Some ecosystems have changed dramatically over recent geological time. How far back in time should we aim to go? Do we try to bring back species that were lost in the last century… or […]

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