Paul Jepson - Rewilding: The Radical New Science of Ecological Recovery

This century is witnessing a fundamental reassessment of the science and practice of nature conservation. An exciting and unsettling body of new thinking is emerging, inspired by the realisation that we have internalised ecological impoverishment in our science, culture and institutions. This impoverishment is a consequence of the syndrome of shifting baselines, where each generation assumes the nature they experienced in their youth to be normal and unwittingly accepts the declines and damage of the generations before.

A generation ago, at the time of the 1992 Rio Earth summit, ecologists and conservation biologists succeeded in raising the fate of biodiversity to the top of the environmental policy agenda. Their science was rooted in the comparative traditions of natural history and the ecology of communities of species and strongly influenced by the protectionist worldviews of 1970s environmentalism. A focus on the components of nature species, sites and habitats translated into clear and powerful law and policy aimed at protecting nature from the wounding ways of humanity. Framing nature as units or components enabled biodiversity targets to be set, and the development of an empirical and international conservation science.

The science of biodiversity, and the institutions it spawned, assumed that the ecosystems that were present at the beginning of the industrial era represented the natural baselines that should be conserved. Indeed, at this time it was considered appropriate that such baselines provided the foundations upon which biodiversity was to be protected and measured. This made intuitive sense as, after all, the tropical rainforests, African savannas and pastoral landscapes of Europe all supported diverse and flourishing natures that were disappearing fast in a globalising world, characterised by increasing population and resource demands.

By the turn of the millennium, biodiversity science had become accomplished and influential. But, like progressive rock in the 1970s, it has also become a little self-serving and out of touch with trends in science and wider society. In particular, the relentless telling of stories of biodiversity decline and an impending sixth-extinction crisis, combined with newer anxieties over climate change, has led to a growing sense of despondency within the conservation movement. Many have started to lose hope and question whether they still want to devote their lives and careers to lessening harm and fruitlessly cataloguing the end of nature.

Then in 2005 and 2006 the prestigious journals Science and The American Naturalist published papers proposing audacious new agendas for conservation science. In the first, titled Pleistocene Park: return of the mammoths ecosystem, Sergey Zimov pointed out that up until 10,000 years ago, much of the Arctic was covered by steppe grasslands, created and maintained by vast herds of mega-herbivores. He argued that their disappearance could be attributed to human hunting pressure, and that the mammoth steppe ecosystem can and should be restored as a strategy to reduce carbon emissions from the thawing yedoma (permafrost) soils. The second paper, authored by a group of US conservation scientists led by Josh Donlan, was Pleistocene Rewilding: an optimistic agenda for twenty-first century conservation. This group pointed out that assemblies of large vertebrates produce complex food webs, and that continental-scale declines of megafauna over the millennia have resulted in downgrading of nature. They outlined an agenda to restore ecological functions through the reassembly of the remaining large herbivore guilds, such as elk, bison, and feral horses and even introduced species from different faunal regions, such as camels. The belief was that such surviving wild herbivores could do the ecological job of lost species and that this rewilding was a better alternative than doing nothing or relying on the ageing and failing protectionist approach of the 1970s.

To continue the music analogy, it was as if punk rock had hit the conservation science scene. The agendas introduced in these papers were brash, energising, novel and controversial. They signified a desire to shake up the present but also expressed an ambition to shape a new and inspiring future. The Pleistocene rewilding concept was robustly criticised by some in the conservation establishment, who accused the authors of opening a Pandoras box and proposing the creation of Frankenstein ecosystems. Yet, the arguments in both papers gave new expression to a scientific riff called functionalism which has subsequently become the scientific basis of rewilding practice.