Megafauna Rewilding: Addressing Amnesia and Myopia in Biodiversity Law and Policy

Abstract

Large mammals (megafauna) are disproportionately important for ecosystem functioning and biodiversity, but have been lost to disproportionate degrees, mostly in prehistoric times. Against the background of scientific knowledge regarding the state of ecosystems before a man-made wave of extinctions significantly reduced the numbers and diversity of megafauna on most continents, this article examines how (inter)national law and policy relate to efforts to restore large herbivores, omnivores and carnivores to terrestrial ecosystems around the world. Such megafauna rewilding, involving the (re)introduction of vanished species or proxies thereof, poses significant challenges to current laws and policies at national and domestic levels. These tend to have institutionalised a collective amnesia and myopia regarding what is ‘natural’ and ‘indigenous’. The success of future megafauna restoration efforts will partly depend on an understanding of what it takes to navigate, adjust or redesign applicable legal frameworks, and the article tables a research agenda to that end.

1. INTRODUCTION

To reverse the deepening global biodiversity crisis, the period 2021–30 has been proclaimed the United Nations (UN) Decade of Ecosystem Restoration.¹ As various high-profile scientific reports are sounding the alarm over the biosphere’s deteriorating state and call for massive recovery efforts,² ecosystem restoration is making its way onto (inter)governmental agendas around the world. For instance, the new EU Biodiversity Strategy states the headline ambition to ‘ensure that by 2050 all of the world’s ecosystems are restored, resilient, and adequately protected’,³ and the adoption of ambitious global targets to restore degraded ecosystems is expected at the next Conference of the Parties (COP)⁴ of the Convention on Biological Diversity (CBD).⁵ A recent UN Environment Programme (UNEP) report summarises the scientific evidence on the rationale of ecological restoration as follows: ‘Ecosystem restoration is a cost-effective way of achieving multiple benefits’ as it can inter alia ‘simultaneously mitigate climate change, slow and reverse biodiversity decline and increase the benefits that people get from nature.’⁶

A common definition of ecological restoration is ‘the process of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed’.⁷ But to what condition should any given area be restored, and how? Is active intervention required—such as the removal of man-made dams from rivers or reintroduction of missing species—or stepping back, or some combination? These are key questions addressed in the context of a rising paradigm in restoration science and practice called ‘rewilding’—the planned practice of restoring food webs (‘trophic rewilding’) and natural dynamics to set ecosystems on trajectories towards more biodiverse states and independent functioning.⁸

For most terrestrial ecosystems, restoration requires boosting the numbers and diversity of large mammals, also termed ‘megafauna’,⁹ including ‘large herbivores from deer and gazelles to horses, camels, and bison to elephants and rhinos as well as large carnivores and omnivores such as wolves, big cats, and bears’.¹⁰ A growing body of research shows that when compared with smaller species, large mammals are (1) disproportionately important for ecosystem functioning, yet (2) have been lost to disproportionate degrees, mostly in prehistoric times.¹¹ However, large species are also (3) disproportionately challenging to re-establish, given spatial requirements and human–wildlife conflict potential.¹² Megafauna restoration is increasingly proposed, and has already occurred in various places, at mostly modest scales.¹³ It can be pursued by enabling spontaneous (re)establishment of species where possible, and by actively translocating—ie (re)introducing—lost megafauna species or proxies thereof.¹⁴ Even the reintegration of globally extinct species, or at least very similar animals, appears possible, through back-breeding with domesticated descendants or through cloning or genome editing.¹⁵

Megafauna rewilding, particularly where it requires active ecological or biological engineering, raises numerous practical, societal and ethical issues, and is increasingly generating scientific research and debate.¹⁶ It also raises significant and complex legal issues, and rewilding researchers and practitioners have raised the question how compatible the novel paradigm is with traditional legal frameworks, which tend to be premised on recent, historic ecological baselines.¹⁷ However, despite a growing number of fruitful analyses by legal researchers of certain aspects of this question within selected jurisdictions and areas of law,¹⁸ the legal perspective remains underexplored. With the possible exception of de-extinction, attention amongst legal scholars still lags behind other disciplines and, more importantly, does not match the key influence that national and international legal frameworks can exercise on megafauna rewilding possibilities.¹⁹

The present article adopts a giraffe’s-eye view of the topic. It aims in broad terms (1) to ascertain and appraise the consequences of the emerging scientific insights on megafauna for biodiversity law and policy, (2) to similarly evaluate the influence of law on megafauna rewilding possibilities, and (3) to outline the legal research agenda waiting to be addressed further in this area. In the process, it aspires to fan the interest of legal researchers in the topic, and to help competent authorities, rewilding practitioners and researchers from other disciplines appreciate the relevance of law, and the kinds of legal questions that arise. The article explores the scientific literature on megafauna rewilding through a legal lens, so as to identify the most significant categories of legal questions likely to be faced by future rewilding initiatives, and potential ways of addressing them. The rationale of an augmented focus on megafauna rewilding in law and policy is explored next. This is followed by an appraisal of the role of law regarding a variety of distinct megafauna rewilding scenarios. The article’s scope is global, but limited to terrestrial megafauna.²⁰

2. REASONS TO FOCUS ON MEGAFAUNA REWILDING IN LAW AND POLICY

The importance of large herbivores, omnivores and carnivores for ecosystem integrity is well documented in the scientific literature, which indicates that ‘complex megafaunas with well-developed large-herbivore assemblages promote landscape-scale biodiversity’²¹ through various mechanisms.²² These mechanisms include (1) the generation of a varied vegetation structure through browsing, grazing and physical disturbance, (2) the dispersal of nutrients and seeds, (3) provisioning of predators, scavengers and parasites and (4) various other subtle ways in which megafauna create and maintain niches for other species of fauna and flora.²³ For example, removing large grazing animals from the landscape can lead to encroachment by woody plants, reduced vegetation heterogeneity and ‘widespread declines in plants and insects adapted for open and semi-open conditions’.²⁴

Megafauna-rich terrestrial ecosystems—dynamic combinations of grassland, savanna and forest teeming with large and small wildlife—are now largely limited to sub-Saharan Africa and Southeast Asia,²⁵ but were the norm across the globe for many millions of years.²⁶ For instance, a variety of elephant(-like) species—elephants, mammoths, mastodons, gomphotheres and stegodonts—inhabited every continent except Australia and Antarctica.²⁷ Indeed, the ‘natural’ state of the world is ‘to have elephants virtually everywhere’.²⁸

2.1 A Prehistoric, Man-Made Megafauna Extinction Wave

And then, within one brief period, largely within the last 50,000 years, one megafauna species after the other disappeared.²⁹ These extinctions which, ‘geologically speaking, happened almost yesterday’,³⁰ were pondered in 1876 by Alfred Russel Wallace, co-inventor of evolutionary theory alongside Darwin, in these famous words:

[W]e are now in an altogether exceptional period of the earth’s history. We live in a zoologically impoverished world, from which all the hugest, and fiercest, and strangest forms have recently disappeared. … Yet it is surely a marvelous fact, and one that has hardly been sufficiently dwelt upon, this sudden dying out of so many large mammalia, not in one place only but over half the surface of the globe.³¹

The riddle of what produced these prehistoric extinctions has since been largely solved. According to the scientific evidence now available, accumulated thanks to radiocarbon dating and other evolving techniques, the demise of the megafauna was caused primarily by our ancestors as they spread across the globe³²—confirming the hunch expressed by Wallace himself in 1911 that the extinctions were mainly ‘due to man’s agency’.³³ Most large mammals in Africa and many in southern Asia escaped extinction, presumably because they co-evolved with humans and developed appropriate behavioural defences. When people began to venture elsewhere, however, one continent and one island after another experienced the ‘ecological shock of human arrival’.³⁴ Paul Martin was one of the first scientists to point out that the ‘sweep of extinctions’ of megafauna began ‘gradually and inconspicuously in Africa over two million years ago, intensified in Europe beginning … 50,000 years ago, hit hard in Australia 40,000–50,000 years ago, and exploded in the Americas around 13,000 years ago’, and then visited oceanic islands, one by one, in the order that humans discovered them.³⁵ A pattern emerges: ‘People turn up and megafauna disappear.’³⁶ As JB MacKinnon tells the story:

Go to any corner of the planet, and the moment that Homo sapiens first shows up in that place will be roughly the time that many of its largest species begin to fall toward the void of extinction. … Fifty thousand years ago, humans reach Australia and twenty-one entire genera (groupings of species with similar characteristics) disappear over the following millennia; every land-based species with an average weight above one hundred kilograms is wiped out. Thirty thousand years ago, modern humans settle in Europe, and nine genera vanish. North America loses thirty-three, with the Americas as a whole shedding 75 percent of their big beasts. Most compelling is the fact that the die-offs taking place on continental mainlands were often postponed on offshore islands, for the simple reason that humans had not arrived on them yet. … Despite being Australia’s neighbor, New Zealand didn’t lose its large fauna – eleven species of flightless moa – until just eight hundred years ago, with the arrival of the Maori culture.³⁷

A common theme in human (pre)history thus seems to be: ‘we came, we saw, we left a deep scar.’³⁸ Climate change may have been a contributing factor in the demise of some species, but would probably not have caused any of the recent extinctions by itself.³⁹ Before the arrival of people, the animals involved had survived the coming and going of multiple ice ages, so even ‘when we say that both climate and people drove the animals to extinction, we really mean we did it’.⁴⁰ Thus, what has been dubbed ‘one of the greatest discoveries in the history of paleontology’ is this: ‘Long before the dawn of written history, human impacts were responsible for a fantastically destructive wave of extinctions around the globe.’⁴¹

The wave’s dimensions have gradually become clearer. According to one comprehensive review, between 130,000 and 1,000 years ago humans caused or contributed to the global or continental extinction of no less than 177 mammal species weighing over 10 kg—Africa lost 18 such species, Europe 19, Australasia 26, Asia 38, North America 43 and South America 62.⁴² Of course, since then, intensifying human impacts have caused further declines, range contractions and extinctions of remaining megafauna (sub)species.⁴³ All of this amounts to a disruption of a ‘multi-million-year-old pattern’ the significance of which is hard to overestimate: ‘For at least 250 million years and through every variation in global climate, life on earth was not so empty of large and fierce beasts as it is today except during periods of cataclysmic mass extinction.’⁴⁴ Humans are clearly in the cataclysmic category.⁴⁵

Adding some mental images to the statistics may be welcome at this stage to aid the reader’s grasp of the prehistoric losses involved and the questions they pose for ecosystem restoration today:

North America lost mastodons, gomphotheres, and four species of mammoths; ground sloths, a glyptodont, and giant armadillos; giant beavers and giant peccaries; stag moose and dwarf antelopes; brush oxen and woodland musk oxen; native camels and horses; short-faced bears, dire wolves, saber-toothed and dirk-toothed cats, and an American subspecies of the king of beasts, the lion. … The survivors of the big wipeout are those large animals familiar to us now, such as bison, brown (grizzly) bears, cougars (mountain lions), deer, elk (wapiti), moose, musk oxen, and pronghorns. Most people regard these as defining ‘wild America.’ They do not. To give so little attention to the dozens of big animals we have lost so recently simply sells North America short. Before extinction of our native big mammals, the New World had much more in common with an African game park than most of us realize.⁴⁶

Likewise, without human interference, Western Europe would in all probability have been home today to straight-tusked elephants (Palaeoloxodon antiquus), Merck’s rhinoceroses (Stephanorhinus kirchbergensis), wild horses (Equus ferus ferus), aurochs (Bos primigenius), cave bears (Ursus spelaeus), Eurasian sabre-toothed cats (Homotherium latidens), lions (Panthera leo), leopards (Panthera pardus) and spotted hyenas (Crocuta crocuta), to name a few.⁴⁷ Similar examples could be given for the diminished faunas of South America, Australia, Madagascar and so forth.

2.2 Rediscovering the Big Picture and Redrawing Baselines

The disappearance of large mammal species and numbers from most of the world’s landscapes, even if virtually instantaneous on geological and evolutionary scales, has still been a gradual development from a human perspective.⁴⁸ The process of defaunation,⁴⁹ like environmental degradation at large, is subject to what fisheries biologist Daniel Pauly has labelled the ‘shifting baseline syndrome’—the ‘gradual accommodation of the creeping disappearance’⁵⁰ of wildlife that results when each generation of humans assumes the state of nature it grew up with as normal and ‘unwittingly accepts’⁵¹ the declines caused by previous generations. A related term is ‘double disappearance’, coined by Ray Rogers to denote the two-step process whereby the disappearance of a species tends to be followed sooner or later by the extinction of people’s knowledge that the species once roamed their country or continent, or ever existed.⁵² As Chris Thomas observes: ‘Despite its brains, Homo sapiens forgets far more than it remembers’.⁵³ As a result, ‘present-day Europeans are generally oblivious to the absence of rhinoceros and lions in their vineyards’ and ‘most North American hikers fail to wonder why four-tonne mastodon elephants are missing from the shores of the Great Lakes’.⁵⁴

A quiet look at this big picture makes clear that any baseline drawn after the prehistoric megafauna extinctions is essentially arbitrary. The Americas that Columbus ‘discovered’ in 1492 were already very far from pristine, and the same is true of the Australia that Willem Janszoon encountered in 1606. Instead, answering the question what a flourishing, well-functioning and resilient biosphere looks like requires looking beyond pre-industrial and pre-colonial baselines, travelling back in time at least 10,000–50,000 years, depending on the location. Only when looking into this deeper (but geologically still very recent) past does it become apparent how great the deviation from normality is that many have begun to call the Anthropocene.

Even so, exactly replicating the Late Pleistocene would not seem a realistic goal for ecosystem restoration.⁵⁵ There are practical obstacles to turning back the ecological clock, given that many megafauna species are globally extinct; that in many ecosystems the complete removal of alien species (introduced by people) appears unfeasible; and that the human world population now runs in the billions. That said, the pre-megafauna-extinction Late Pleistocene does present a standard to be approached as closely as possible within current conditions in the 30–50% of the planet’s terrestrial surface area that will be earmarked for nature in the near future if the growing scientific and (inter)governmental consensus on ecological restoration is put into practice. Notably, prioritising nature conservation and restoration in approximately 50% of each ecoregion appears to be practically and economically feasible while still adequately sustaining the human world population.⁵⁶ Time will tell whether the ‘transformative changes’⁵⁷ that are necessary to implement this vision will also turn out to be politically feasible. Prevailing attitudes in societies across the globe have opposed change on many occasions, but have adjusted quickly and radically on others. An apt example is the history of wolves (Canis lupus) in Europe—subject to active and government-sponsored persecution for centuries, but now protected and making a spectacular comeback.⁵⁸ The charismatic appeal of many megafauna species should be noted in this connection, which may act to ameliorate public resistance to their return.⁵⁹ In any event, this article departs from the optimistic but not unreasonable working assumption in international law and policy that governments may in principle be expected to honour their commitments.

2.3 Reasons for Megafauna Rewilding

As highlighted above, restoring ecological integrity is a principal reason for re-establishing ‘functionally diverse faunas of large-bodied animals’⁶⁰—whether involving native animals or proxies for lost species. In the words of a leading expert on trophic rewilding, ‘megafauna restoration should play a central role’ in current ecological recovery agendas if only because the return of autonomously functioning ecosystems with rebuilt food webs ‘reinstates the only proven effective long-term mechanism for generating and maintaining biodiversity’.⁶¹

A second reason for megafauna (re)introductions is that they can contribute to species survival, as many of the species involved are threatened in their current range due to unsustainable killing, habitat loss and/or climate change.⁶² For example, Asiatic black bears (Ursus thibetanus, moon bears) are under pressure in their current Asian range, and listed as ‘vulnerable’ on the Red List of the International Union for the Conservation of Nature (IUCN).⁶³ Reintroducing the species to Europe, where fossil bones have been found as far west as Germany and France,⁶⁴ could thus improve its prospects. Likewise, introducing Asian elephants (Elephas maximus) to South America would not only provide a surrogate to begin refilling the ecological vacuum left by extinct American proboscideans, but also increase the chances of long-term survival of the species itself, currently red-listed as ‘endangered’.⁶⁵ Similar considerations apply, to provide a final example, to the introduction of African cheetahs (Acinonyx jubatus) to North America as proxy for the extinct American cheetah (Micracinonyx trumani), not only taking up the latter’s ecological role vis-à-vis the pronghorn antelope (Antilocapra americana) and other wildlife, but again also helping ensure cheetah survival per se.⁶⁶

A third set of reasons is that ecosystems with restored megafauna can deliver ‘nature-based solutions’ in the field of climate change mitigation and adaptation—including flood management, carbon storage⁶⁷ and wildfire control⁶⁸—and other co-benefits such as zoonotic disease prevention,⁶⁹ control of invasive species,⁷⁰ soil health and ecotourism opportunities.⁷¹

Last but not least, there is a notable normative undercurrent to megafauna rewilding, involving notions of righting past wrongs and equitable burden-sharing. In fact, the most important reason of all may quite simply be that ‘as the species responsible for the extinction of so many taxa, humans have a corresponding responsibility to attempt their restoration when feasible.’⁷² Equally, the burden of co-existing with potentially harmful and dangerous large mammals is at present very disproportionately borne by some of the world’s poorest human populations.⁷³ Megafauna restoration in the Americas, Europe and Australia can help rectify this skewed situation.

In sum, there seems to be no lack of compelling reasons for biodiversity policies and legislation around the world to promote and enable megafauna rewilding.

3. CHARTING, NAVIGATING AND ENHANCING THE ROLE OF LAW IN MEGAFAUNA REWILDING

But how conducive are law and policy to ecological and biological engineering efforts to return to (a modern version of) the ‘natural’ situation where large mammals play their customary role in the earth’s ecosystems? What legal obstacles exist, and how can these be overcome? These are questions that invite further investigation by legal scholars—building on the work already done⁷⁴—in tandem with researchers from other relevant disciplines, in national jurisdictions around the globe, and also with regard to international legal frameworks. In particular, this would involve addressing the following interrelated questions: (1) in what ways and to what degrees does (inter)national law influence current and prospective megafauna rewilding; (2) how can megafauna rewilding be conducted successfully under present legal frameworks; and (3) what can be done to optimise the law’s role in this regard?

Below, these questions are unpacked in some more detail, and some beginnings of answers offered. Before proceeding, certain basic observations are in order. Law, whether domestic or international, is a potentially strong tool for megafauna conservation and restoration.⁷⁵ Yet, the role played by law in this context can be restrictive as well as supportive. On the one hand, legislation can support or require ecosystem restoration, including by promoting the comeback or (re)introduction of certain species. On the other hand, legislation can impose restrictions or conditions on rewilding possibilities. These may follow from rules on indigenous species protection, area protection, non-indigenous species (especially ‘invasive alien species’), disease, biotechnology and genetically modified organisms, trade, animal welfare and several further areas (from property to tort law). Such restrictions will hamper megafauna rewilding efforts especially to the extent that they institutionalise ‘amnesia’ regarding appropriate ecological baseline conditions. Environmental law standards that fail to account for past impacts can ‘perpetuate’ shifted baselines and ‘blind decision-makers to the magnitude’ of prior losses.⁷⁶

3.1 Megafauna Rewilding and General Obligations to Restore

General obligations to restore ecosystems and biodiversity flow from many international legal instruments.⁷⁷ For instance, the CBD requires its parties ‘as far as possible and as appropriate’ to ‘[r]ehabilitate and restore degraded ecosystems and promote the recovery of threatened species’.⁷⁸ The Central American Biodiversity Convention sets out a similarly phrased requirement at the regional level.⁷⁹ Despite their general and qualified formulations, these commitments are not utterly discretionary.⁸⁰ (Re)introducing extinct megafauna or proxies thereof seems compatible with these obligations, but to what extent such actions are actually required will be a matter of interpretation in each concrete instance.

An especially interesting example is the Protocol on Biodiversity to the Carpathian Convention (Carpathian Biodiversity Protocol).⁸¹ Each party ‘shall develop and implement policies and strategies in its national territory aiming at the conservation, restoration and sustainable use of biological … diversity of the Carpathians’⁸² and ‘take measures in its national territory with the objective to ensure the long-term conservation, restoration and sustainable use of natural habitats in the Carpathians’.⁸³ Significantly, the term ‘restoration’ is defined as the ‘return of an ecosystem or habitat to its original structure, natural composition of species, and natural functions’.⁸⁴ Ongoing efforts for the range expansion and reintroduction of European bison (Bison bonasus) populations in the Carpathians appear good examples of these obligations’ implementation.⁸⁵ Moreover, a good argument can apparently be made that a textual and teleological⁸⁶ interpretation of the word ‘original’ entails a baseline drawn before the Late Pleistocene megafauna extinctions, and that the scope of the aforementioned provisions therefore also encompasses leopards, lions, Asiatic wild asses (Equus hemionus, onager, khulan) and several other extirpated species, and even proxies for the aurochs, rhinoceroses, elephants and other globally extinct species that used to roam the Carpathian region.⁸⁷ This interpretation appears compatible with the recent call on parties by the Carpathian Convention COP, in connection with the UN Decade on Ecosystem Restoration, to ‘make strong commitments to achieve transformational ecosystem restoration’.⁸⁸

3.2 Spontaneous Range Expansions Within and Beyond Indigenous Range

The least controversial mode of megafauna (re)establishment is promoting or at least allowing a locally disappeared but indubitably indigenous species to resettle its former range by itself. One of many available examples is the natural recolonisation by mountain lions (Puma concolor) of parts of their former American distribution area.⁸⁹ A prime European example is the recent natural comeback of wolves, under cover of protective legislation, to various countries from which they had been extirpated.⁹⁰ The protected status that wolves receive under EU law travels along with them across international borders, and Member States where wolves reappear after a long absence are basically expected to receive them with open arms, and focus on enabling renewed coexistence with people.⁹¹

The spontaneous arrival of formerly non-indigenous species raises more questions. Coyotes (Canis latrans), for instance, have been expanding deep into Central America and appear poised to colonise South America, a continent without prior records of the species.⁹² Meanwhile, in Europe, golden jackals (Canis aureus) are expanding across the continent, again to places where the species appears to be an ecological novelty.⁹³ A first question is whether in newly colonised areas these canids qualify as ‘alien species’ whose settlement is to be discouraged. The answer appears to be no. Both carnivores explore terra incognita on their own four feet, which means that a core ingredient from alien species definitions is missing, namely, introduction by man.⁹⁴ For example, according to the CBD COP, an ‘alien species’ is a species ‘introduced outside its natural past or present distribution’, with ‘introduction’ understood as involving ‘movement by human agency’.⁹⁵ Equally, the EU Invasive Alien Species Regulation⁹⁶ applies to ‘all invasive alien species’,⁹⁷ and not to ‘species changing their natural range without human intervention, in response to changing ecological conditions and climate change’.⁹⁸

A second question is whether ‘natural range’ and similar concepts should be viewed as rigid or malleable. In the cases of the EU Habitats Directive⁹⁹ and the Convention on Migratory Species (CMS)¹⁰⁰ at least, the answer is the latter.¹⁰¹ The Habitats Directive confers various degrees of protection on the species listed in its annexes—including the golden jackal—in their ‘natural range’.¹⁰² As the European Commission puts it, ‘when a species spreads on its own to a new area/territory’, this area ‘has to be considered part of the natural range’ for the purposes of the Directive.¹⁰³ Furthermore, the EU Court of Justice recently confirmed that wild animals straying into human settlements must also still be regarded as being within their ‘natural range’.¹⁰⁴ The term ‘range’ as employed in the CMS is similarly flexible, comprising ‘all the areas of land …that a migratory species inhabits, stays in temporarily, [or] crosses’.¹⁰⁵ The term ‘historic coverage’, part of the Convention’s understanding of a ‘favourable conservation status’,¹⁰⁶ is potentially more problematic (especially in light of climate change) but has also been subject to a flexible and pragmatic interpretation by the CMS COP:

Whereas there is a continued need to undertake conservation action within the historic range of migratory species, such action will increasingly also need to be taken beyond the historic range of species in order to ensure a favourable conservation status, particularly with a view to climate-induced range shifts.¹⁰⁷

3.3 Translocating Indigenous Megafauna: Reintroduction and Reinforcement

The question of species’ status as either ‘indigenous’ (‘native’) or ‘alien’ (‘non-native’) becomes acute when physical wildlife translocations by people—by truck, plane or otherwise—are involved. From a law and policy perspective, this is a major divide. For the former category, the CBD requires parties to ‘promote the recovery of threatened species, inter alia, through the development and implementation of plans or other management strategies’,¹⁰⁸ and to ‘[a]dopt measures for the recovery and rehabilitation of threatened species and for their reintroduction into their natural habitats under appropriate conditions’.¹⁰⁹ In contrast, the latter category of species is the focus of an obligation in the same Convention to ‘[p]revent the introduction of, control or eradicate those alien species which threaten ecosystems, habitats or species’.¹¹⁰

It is helpful here to reproduce the categories of translocations for conservation purposes as defined in an authoritative IUCN guidance document:

Population restoration—within ‘indigenous range’:

• Reinforcement: ‘the intentional movement and release of an organism into an existing population of conspecifics’

• Reintroduction: ‘the intentional movement and release of an organism inside its indigenous range from which it has disappeared’

Conservation introduction—outside ‘indigenous range’:

• Assisted colonisation: ‘the intentional movement and release of an organism outside its indigenous range to avoid extinction of populations of the focal species’

• Ecological replacement: ‘the intentional movement and release of an organism outside its indigenous range to perform a specific ecological function’¹¹¹

These distinctions can be legally significant. It is also important to realise that the meaning of key terms, such as ‘indigenous’, ‘native’, ‘alien’, ‘invasive’, ‘historic’ and ‘natural’ can vary from one legal regime to the next, and that definitions used by natural scientists can differ from those employed in law. Moreover, in practice, these concepts may not always be used in an entirely consistent manner by governmental actors, whether an authority granting or refusing a translocation permit, or a court reviewing such a decision.¹¹²

Various legal instruments besides the CBD expressly call for reintroduction in the sense of the IUCN guidelines,¹¹³ including the CMS,¹¹⁴ the Convention on European Wildlife and Habitats (Bern Convention)¹¹⁵ and the Carpathian Biodiversity Protocol.¹¹⁶ Examples of past large mammal reintroductions include European bison¹¹⁷ and Eurasian lynx (Lynx lynx)¹¹⁸ reintroductions in various countries; reintroduction of Przewalski’s horse to Mongolia;¹¹⁹ reintroductions of various gazelle and oryx species in northern Africa and western Asia;¹²⁰ the return of several rhinoceros species to places in Africa and Asia where they were extirpated;¹²¹ collared peccary (Pecari tajacu) reintroduction in Argentina;¹²² and the famous wolf reintroduction in Yellowstone National Park.¹²³ An example of a megafauna reinforcement operation is the restocking of the feeble brown bear (Ursus arctos) population in the French Pyrenees with bears from Slovenia.¹²⁴ Notably, legal obligations to reinforce or reintroduce may also arise from failures to conserve. For example, when a protected area has been designated for a certain species under the Habitats Directive and the species subsequently disappears from the site due to anthropogenic causes such as poaching, then the EU Member State involved is required to restore the species to the area—a topical example being the recently extinct wolf population of Spain’s Sierra Morena region.¹²⁵

The IUCN guidelines rightly draw attention to the fact that conservation translocation proponents may need to meet ‘regulatory requirements at any or all of international, national, regional or sub-regional levels’.¹²⁶ These requirements can pertain to a plethora of issues, including invasive alien species, protected areas, indigenous species protection, international wildlife trade, the translocation’s scientific basis, stakeholder participation, disease prevention and other veterinary standards, animal welfare, access to land, the keeping of dangerous animals and other public safety issues.¹²⁷ In most cases, one or more permits for the capture, keeping, transport and/or release of the animals in question will be required under the domestic legislation of the source, transit and destination countries involved.¹²⁸ Compliance with the substantive criteria set out in the IUCN conservation translocation guidelines themselves—which require inter alia that the original causes of extinction of the species concerned have been removed or significantly reduced and that its habitat requirements are satisfied—tends to be helpful and can be mandatory for the acquisition of such permits.¹²⁹ What legal requirements apply exactly will depend on the species, sites and countries involved, and acquiring a good understanding of applicable law at all levels is an essential element of any given megafauna rewilding project—and can determine success or failure.¹³⁰

A problem regarding species that disappeared thousands or tens of thousands of years ago is that they simply tend to be lacking from the radar of current (inter)national law and policy frameworks on restoration and reintroduction. Even if laws on wildlife conservation (and invasive species) typically ‘seek to promote the preservation or restoration of past historic conditions’,¹³¹ baselines are often drawn in the recent past—a few decades (eg from a legal instrument’s entry into force) to at most a few centuries ago.¹³² Continentally extinct species are usually absent from lists of protected species or target species for protected areas. Generally, as institutionalised representations of the shifting baseline syndrome, biodiversity law and policy are geared more towards maintaining the status quo or mimicking the recent past than to welcoming species from the distant past—even if on a longer timescale the latter may be extremely archetypal in ecological terms.

The Bern Convention and Habitats Directive are fairly representative. Their appendices feature ibex (Capra ibex) and European bison but not hippopotamus (Hippopotamus amphibius), and they list wolf and brown bear but not lion or spotted hyena (Hyaena hyaena), even if all of these species roamed the European continent together not that long ago.¹³³ The Habitats Directive’s objective of a ‘favourable conservation status’, and the associated obligations of Member States to monitor, protect and restore, apply only to species now present in the EU, especially those listed in the Directive’s annexes.¹³⁴ The most recent EU-wide conservation status reporting exercise¹³⁵ is thus useful as a ‘health check’¹³⁶ for the species and habitat types currently covered, but not for ecosystem health more broadly, as it utterly disregards many extinct and extirpated (megafauna) species. Likewise, the scope of the Directive’s provision on reintroduction is confined to species already included in its Annex IV.¹³⁷ What is more, (re)introducing an unlisted species within or near a site that is part of the Natura 2000 protected area network may, in principle, only be done if it is ‘directly connected with or necessary to the management of the site’, or after the authorities involved have made certain—beyond a ‘reasonable scientific doubt’¹³⁸—that the project will not have significant adverse impacts on the species or habitat types for which the site was designated.¹³⁹ In combination with the Directive’s blind spot for lost megafauna, this evidentiary bar (which has otherwise proven extremely important for the protection of current species and habitats) could pose a formidable obstacle to megafauna rewilding efforts in or near Natura 2000 sites.¹⁴⁰

The Bern Convention is to some extent an interesting exception, and its myopia a little less severe than the Directive’s. Firstly, the scope of the Convention’s reintroduction obligation is not limited to listed species:

Each Contracting Party undertakes … to encourage the reintroduction of native species of wild flora and fauna where this would contribute to the conservation of an endangered species, provided that a study is first made … to establish that such reintroduction would be effective and acceptable.¹⁴¹

Secondly, the aforementioned strict evidentiary requirement of the Habitats Directive for plans or projects potentially threatening protected areas is absent from the Bern Convention.¹⁴² Thirdly, amongst the strictly protected species included in Appendix II of the Convention are the dhole (Cuon alpinus, Asiatic wild dog) and the leopard—both of which were once full European residents—and even the tiger (Panthera tigris).¹⁴³ Especially for these species, the Bern Convention provides a potentially interesting legal springboard for future European reintroduction projects, as their listing can be taken to support a presumption of indigenous status in (parts of) Europe.

The CMS, for the many large mammals in its appendices, aspires to situations where the ‘distribution and abundance’ of these species ‘approach historic coverage and levels to the extent that potentially suitable ecosystems exist and to the extent consistent with wise wildlife management’.¹⁴⁴ Parties are also expressly called on, ‘where it appears desirable’, to arrange for ‘reintroduction’ of Appendix II species ‘into favourable habitats’, and for the ‘provision of new habitats favourable to the migratory species’.¹⁴⁵ The question arises to what extent the Convention thus provides support for reintroductions of species extirpated in the remote past. Given the Convention’s objective of migratory species conservation and the flexible and pragmatic way its terms have been interpreted by parties in the past, the CMS can be expected to further rather than hinder such reintroductions.¹⁴⁶

3.4 Translocating Non-Indigenous Megafauna: Assisted Colonisation and Ecological Replacement

Initiatives to introduce non-indigenous species are likely to face additional hurdles, including legal ones. This can also apply at the subspecies level, as illustrated by a proposed translocation of African cheetahs (Acinonyx jubatus jubatus) from Namibia to India, to replace the Asiatic cheetah subspecies (A. j. venaticus) that was extirpated in India in the previous century.¹⁴⁷ In 2012, the Supreme Court of India outlawed such a translocation, partly because of incompatibility with a previous version of the IUCN translocation guidelines.¹⁴⁸ In 2020, the same court considered the legality of a renewed proposal to translocate the species on an experimental basis, finding inter alia that:

the word ‘re-introduce’ has been erroneously applied since it is an admitted fact that the African Cheetahs never inhabited in [sic] India. Therefore, if an attempt is made to relocate the African Cheetah within the territory of India, it will amount to an ‘introduction’ … and not a ‘re-introduction’.¹⁴⁹

Still, on this occasion, the Court eventually approved the operation.

As the IUCN guidelines emphasise, translocations beyond indigenous range are considered as ‘especially high risk given the numerous examples of species released outside their indigenous ranges subsequently becoming invasive, often with massively adverse impacts’.¹⁵⁰ Hence, when a megafauna introduction involves a (putatively) non-indigenous species, potentially significant obstacles can emerge from (inter)national legislation on invasive alien species. To illustrate, the aforementioned CBD obligation to deal with such species has been elaborated in COP guidance,¹⁵¹ which recommends the following approach:

An appropriate risk analysis … should be carried out as part of the evaluation process before coming to a decision on whether or not to authorize a proposed introduction … . States should make all efforts to permit only those species that are unlikely to threaten biological diversity. The burden of proof that a proposed introduction is unlikely to threaten biological diversity should be with the proposer of the introduction or be assigned as appropriate by the recipient State.¹⁵²

Many regional agreements and national laws reflect similar requirements.¹⁵³

Sometimes it is beyond dispute that the species involved in an envisaged translocation is non-indigenous in the destination area. Introducing any of the extant elephant species to the New World would be an example, as these are evidently distinct from all extinct American proboscideans, even if they may be close functional proxies in ecological terms.¹⁵⁴ An even plainer scenario is the introduction of elephants or rhinoceroses to Australia—whether for reasons of ecological replacement, species survival or both¹⁵⁵—as neither of these species groups were ever native to the Australian continent. In all such cases, the species will likely be considered ‘alien’ before the law, so that the focus will come to rest on proving and ensuring that it will not become ‘invasive’, ie a threat to local biodiversity¹⁵⁶—which may not be easy.¹⁵⁷

In other cases, the matter may be debatable. To revisit the example of returning Asiatic black bears to Europe, would this be considered an introduction or a reintroduction? The law and policy of the target country or countries involved may well consider these bears non-indigenous, given their millennia-long absence. The current IUCN translocation guidelines, however, open the door to a more generous interpretation of the term ‘indigenous’, as based not only on written or oral historical sources but on fossil evidence as well. The guidelines employ the term ‘indigenous range’ instead of ‘historical range’, and the term’s definition appears to give the species involved the benefit of any remaining doubt:

The indigenous range of a species is the known or inferred distribution generated from historical (written or verbal) records, or physical evidence of the species’ occurrence. Where direct evidence is inadequate to confirm previous occupancy, the existence of suitable habitat within ecologically appropriate proximity to proven range may be taken as adequate evidence of previous occupation.¹⁵⁸

This is a departure from a more narrow—and problematic¹⁵⁹—approach taken in predecessors of the IUCN guidelines. A 1987 position statement defined ‘introduction’ as the ‘intentional or accidental dispersal by human agency of a living organism outside its historically known native range’, while defining ‘re-introduction’ as the ‘intentional movement of an organism into a part of its native range from which it has disappeared or become extirpated in historic times’.¹⁶⁰ In slightly more general terms, reintroduction guidelines adopted in 1998 defined ‘re-introduction’ as an attempt to establish a species ‘in an area which was once part of its historical range’.¹⁶¹ The ‘historical’ element is not only absent from the present (2013) IUCN translocation guidelines, but also from IUCN guidelines on invasive alien species from 2000, according to which a ‘native’ or ‘indigenous’ species means a ‘species, subspecies, or lower taxon, occurring within its natural range (past or present) and dispersal potential’.¹⁶² The evolution of these IUCN documents is significant, given their influence as ‘best practice’ guidelines on the application of national legislation, including decisions on (re)introduction permit applications.

It is important to note, in any case, that assisted colonisation and ecological replacement operations can often be based on, and sometimes be required by, international legal obligations on species conservation and ecosystem restoration¹⁶³—even if they are not yet nearly as firmly anchored in law as reintroduction.¹⁶⁴ Depending on the circumstances, and as illustrated above, certain megafauna rewilding translocations might do ‘double duty’ and qualify simultaneously as ecological replacement and assisted colonisation.

3.5 Other Legal Questions Affecting Megafauna Rewilding

Many further (legal) issues affect megafauna rewilding possibilities. Because of space limitations, only some of these are touched upon here.

Rewilding projects using certain (de-domesticated) cattle or horse breeds as ecological stand-in for extinct counterparts, or indeed back-bred animals that are considered ‘de-extinct’ versions of the ancestors themselves (aurochs, wild horse), may face obstacles arising from the continued applicability of veterinary, husbandry and public liability rules designed for domesticated animals.¹⁶⁵ Incidentally, veterinary legislation may also hamper reintroductions of non-domesticated animals, such as European and American bison (Bison bison), which can carry livestock diseases.¹⁶⁶

‘De-extinction’¹⁶⁷ through cloning and genome editing gives rise to a particularly impressive battery of legal questions, under wildlife law but also in areas such as biotechnology and intellectual property. Understandably, the possibility of (partial) resurrection through such methods of woolly mammoths (Mammuthus primigenius), thylacines (Thylacinus cynocephalus) and other species has captured the imagination of legal scholars like no other aspect of megafauna rewilding,¹⁶⁸ and much has already been written on the subject, from the patentability of the (re)created animals¹⁶⁹ to their legal status under (inter)national biodiversity legislation.¹⁷⁰ Many open questions remain. For instance, when would an engineered ‘de-extinct’ animal count as ‘wild’ in terms of applicable legal instruments?¹⁷¹ For present purposes, it is important to note, in the words of Alejandro Camacho, that even a ‘de-extinct’ species ‘whose introduction might be expected to bring substantial ecological benefits would nevertheless be proscribed in many jurisdictions’.¹⁷² The 2016 IUCN guidelines on the creation of proxies of extinct species, which can be expected to exercise certain influence on the application and evolution of relevant national legislation, focus solely on ecological justifications for de-extinction, stating that ‘the legitimate objective for the creation of a proxy of an extinct species is the production of a functional equivalent able to restore ecological functions or processes that might have been lost as a result of the extinction of the original species.’¹⁷³

Another interesting phenomenon—still waiting for substantial legal research attention—is what might be called de facto rewilding, comprising historic introductions of non-indigenous (sub)species for purposes other than conservation (eg hunting) and the accidental establishment of non-indigenous animal populations following escape from captivity.¹⁷⁴ Examples of the former include African oryx (Oryx gazelle, gemsbok) in the USA,¹⁷⁵ and aoudad (Ammotragus lervia, Barbary sheep) in Spain.¹⁷⁶ A high-profile example of the latter is the small hippopotamus population in Colombia, founded by escapees from Pablo Escobar’s ranch.¹⁷⁷ One study found that 22 of the largest herbivore species (≥100 kg) have introduced populations outside their ‘native’ range.¹⁷⁸ These are evidently of significant interest from a megafauna rewilding perspective, as the species involved may carry out functions of extinct megafauna, and contribute to species survival, even if concerns may also arise regarding adverse impacts on local ecosystems.¹⁷⁹ The aoudad, for instance, is not doing well in its native North African range and red-listed as ‘vulnerable’, so that the Spanish populations, and others in Mexico and the USA, give the species a firmer lease on the future.¹⁸⁰ Regarding its ecological role, it seems the aoudad’s presence in its non-indigenous range can be both beneficial and harmful, depending on the circumstances.¹⁸¹ A prime example of a historic introduction that has become a conservation success story concerns the banteng (Bos javanicus).¹⁸² This large bovid is red-listed in its native range in Southeast Asia as ‘endangered’ due to hunting, habitat loss and hybridisation,¹⁸³ but its prospects have been boosted by its inadvertent establishment in the wild in Australia in the 19th century.¹⁸⁴ Indeed, the Australian population now appears to be larger, and genetically purer, than the native Asian population.¹⁸⁵ As one study concludes:

The successful establishment of Australian banteng was largely accidental, but it does provide a real-world example of how successful introductions of threatened, large-bodied species outside their native range can be achieved.¹⁸⁶

These and other cases of de facto rewilding are also interesting from a legal perspective, and can potentially provide precedents and lessons learnt for future megafauna introductions. It appears worthwhile to study past experiences with such species from the perspective of applicable legal frameworks, and to explore to what extent such species have, or could, eventually become ‘naturalised’ to indigenous status before the law.¹⁸⁷

Law also has a role to play in preventing, mitigating and resolving human–wildlife conflict associated with megafauna restoration.¹⁸⁸ Furthermore, rewilding efforts can be catalysed or hindered by tax regulations and subsidy schemes.¹⁸⁹ As hinted at previously, a wide array of further rules in other areas than biodiversity conservation can rigorously curtail the possibilities for meaningful megafauna rewilding. For instance, scavenging opportunities may be restricted by biohazard legislation requiring the removal of cattle and horse carcasses from the landscape, and the process of predation itself may be precluded in smaller fenced areas if these happen to fall within the scope of rules designed for zoo facilities—requiring separate lodging of predator and prey species.¹⁹⁰

And then there is the important perspective of rights. As the case may be, individual rights and those of indigenous and other communities can provide either an impetus or obstacle for megafauna restoration. To illustrate, private rights such as property rights over land and wildlife, and grazing rights on public lands, have greatly influenced megafauna rewilding potential in countries such as South Africa¹⁹¹ and the USA.¹⁹² Moreover, from the perspective of wildlife itself, there is ample scope for scholars to grapple with the ‘rights of nature’ approaches gaining traction worldwide.¹⁹³ For example, if one were to entertain the possibility of wild animals having something like a right to an adequate habitat or property rights over habitat,¹⁹⁴ or the right not to be exterminated as a species,¹⁹⁵ then how about restorative justice, and how about (pre)historic rights?

4. CONCLUDING OBSERVATIONS

4.1 Findings

At least three things are clear from the above analysis. Firstly, there are compelling reasons to accord megafauna a prominent role in the ambitious and urgent ecosystem restoration efforts to which countries around the world are increasingly committing themselves, and to harness biodiversity law and policy to that end.¹⁹⁶

Secondly, however, the actual pursuit of meaningful megafauna rehabilitation appears to pose significant challenges to current law and policy frameworks at national and international levels. Existing wildlife laws and policies tend to be products of a ‘long-term pattern of amnesia’¹⁹⁷ going hand in hand with progressively myopic perceptions of what is ‘natural’. In some settings, re-interpretations may result in the law enabling, promoting or even requiring megafauna rewilding. In other cases, it may be necessary to amend the law itself. The success of future megafauna rewilding efforts will partly depend on a solid understanding of what it takes to navigate, adjust or redesign applicable legal frameworks.

Thirdly, then, there is ample scope and need for further legal research—the identification, interpretive analysis, comparison and application to factual circumstances of relevant legal instruments, associated policy instruments and case law, building on existing literature—combined with analyses of natural and social science literature on the ecological, practical, socio-economic and ethical aspects of megafauna rewilding. This multi-disciplinary research agenda calls for horizontal analyses of relevant global, regional, national and local legal frameworks, as well as vertical, bottom-up analyses of relevant law and policy in specific jurisdictions from the angle of any of the wide range of concrete rewilding scenarios introduced above. Such research is likely to render valuable insights regarding gaps and obstacles in the law, and what it takes to bridge them. Megafauna rewilding ‘requires innovation in science, policy and practice’¹⁹⁸—and clearly also in law.

4.2 Perspective

In sum, the implications of the recent scientific insights reviewed above for biodiversity law and policy are significant, even radical, and the ensuing research agenda is important and attractive. In many cases those implications will also be rather controversial, as rewilding can ‘conflict with prevalent and powerful institutions and cultural norms’.¹⁹⁹ At present, the need for megafauna restoration is scarcely in the public eye, and concrete initiatives—like most proposed changes to the status quo—may receive more opposition than support. To illustrate, as one commentator observed, the ‘clamour for the lion’s reintroduction to Britain has, so far, been muted’.²⁰⁰ Indeed, wildlife reintroduction proposals, especially when involving potentially dangerous large animals, would appear to be ‘easy material for those wanting to generate populist outrage’.²⁰¹ Controversy can also arise over changes in treatment of very familiar megafauna, eg when active population management (through hunting) of ungulates is abandoned, or animals previously known only as livestock are de-domesticated. For instance, the internationally famous, pioneering rewilding project in the Dutch Oostvaardersplassen was recently severely curtailed by a provincial government succumbing to mounting public pressure over (arguably misplaced) animal welfare concerns regarding the unmanaged populations of red deer (Cervus elaphus) and rewilded horses and cattle involved.²⁰²

Presently, the awareness that elephants roaming virtually all continents is the natural state of the world, let alone something to aspire to, is ‘hardly the norm’.²⁰³ Yet, if widely endorsed notions of intra-generational equity and North–South solidarity are to be taken seriously, perhaps it should be.²⁰⁴ As Tim Flannery puts it:

Many people find the prospect of elephants wandering the forests of Europe ridiculous, or even dangerous. Yet they accept that Africans must share their homes with the ponderous creatures. I think that we should take the long view and share the burden of conservation more equally.²⁰⁵

It is worth fleshing out this illustration a little. Tanzania has a human population density of 67 people/km² and a GDP of just over 60 billion USD. It is also home to significant numbers of elephants, hippopotamuses, lions, crocodiles and other potentially dangerous and conflict-prone wildlife.²⁰⁶ Norway has 15 people/km² and a 400 billion dollar GDP. Yet, its society has been struggling for decades over the return of wolves to the country, and its government has adopted a national maximum of just six wolf packs, tolerated only in a zone covering a few percent of Norwegian territory.²⁰⁷ Now imagine, for the sake of the argument, a hypothetical scenario in which Tanzania were to announce, at a CBD COP, that as part of its national biodiversity strategy it intends to set a national maximum of six elephant family units, six lion prides and so on, and cull the ‘surplus’ thousands of animals. Would Norway, and the Norwegian public, be indifferent? And how would the reaction be from the UK—once home to impressive megafauna, including a rich guild of large carnivores, all of which have subsequently been extirpated and none of which has yet been reintroduced?

It has gradually become apparent from the preceding exploration that enabling megafauna rewilding fundamentally requires addressing various manifestations of collective and institutionalised amnesia and myopia, and broadening perceptions of what is ‘natural’ and ‘indigenous’. To illustrate, someone who views the comeback of wolves to western Europe as a ‘natural’ process might at the same time dismiss a proposed reintroduction of leopards as ‘artificial’—whereas such a reintroduction would really end the highly artificial situation of not having leopards around. Likewise, the relative willingness of European publics to entertain reintroduction proposals for lynx or brown bears, and the expected opposition to similar proposals for dholes or hyenas, manifest a marked tendency to consider only the most recent past and the nearest topography. As exemplified here, perspective and awareness are key—evoking the well-known and presently rather apt image of the elephant and the blind men.

It is the experience of at least some people²⁰⁸ that once one has acquired a basic knowledge regarding the extirpated large mammal species and the ecological importance of abundant and diverse megafauna—ie once one has a rough idea what a ‘natural’ ecosystem is wont to look like—then this awareness simply becomes hard to ignore.²⁰⁹ It then becomes difficult not to view currently prevailing concepts of nature as ‘historically shortsighted and far too tame’, to borrow Martin’s words.²¹⁰ Obviously, knowing what truly ‘natural’ baseline situations are like is not the same as saying that restoration to something resembling it can or should be achieved overnight, or that doing so would be unproblematic. But these baseline situations do present horizons towards which to guide ecosystem restoration efforts where possible, one step at a time.²¹¹

In the mid-19th century, Henry David Thoreau recorded these reflections on ‘primitive nature’ in his journal:

I take infinite pains to know all the phenomena of the spring … thinking that I have here the entire poem, and then, to my chagrin, I hear that it is but an imperfect copy that I possess and have read, that my ancestors have torn out many of the first leaves and grandest passages, and mutilated it in many places. I should not like to think that some demigod had come before me and picked out some of the best of the stars. I wish to know an entire heaven and an entire earth.²¹²

Thoreau had little idea how incomplete the poem before him really was.²¹³ Since he wrote these words, scientists have been discovering in ever more detail how much is actually missing. Whereas melancholy and chagrin are never far when biodiversity loss is contemplated, a distinctly optimistic streak also runs through the literature on megafauna rewilding, caused by the apparently well-founded belief that it is still possible to piece together at least a modern version of Thoreau’s original poem, based on the old theme, and restore ecosystems to something approaching their former glory.²¹⁴ It is fitting to end with a line by George Monbiot, which captures these two contrasting dimensions particularly well: ‘We live in a shadowland, a dim, flattened relic of what there once was, of what there could be again.’²¹⁵

Footnotes

1

UN General Assembly Resolution 73/284 on the United Nations Decade on Ecosystem Restoration, A/RES/73/284 (2019).

2

Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), Summary for Policymakers of the Global Assessment Report on Biodiversity and Ecosystem Services of the IPBES, IPBES/7/10/Add.1 (2019); WWF, Living Planet Report 2020–Bending the Curve of Biodiversity Loss (WWF 2020); Secretariat of the Convention on Biological Diversity, Global Biodiversity Outlook 5 (CBD Secretariat 2020).

3

European Commission, ‘EU Biodiversity Strategy for 2030’ COM (2020) 380 final, 3.

4

Update of the Zero Draft of the Post-2020 Global Biodiversity Framework, CBD/POST2020/PREP/2/1 (2020).

5

Convention on Biological Diversity (1992) 1760 UNTS 79.

6

UNEP, Making Peace with Nature: A Scientific Blueprint to Tackle the Climate, Biodiversity and Pollution Emergencies (NEP 2021) 113.

7

George D Gann and others, ‘International Principles and Standards for the Practice of Ecological Restoration – Second Edition’ (2019) 27 Restoration Ecology S1, S7.

8

Christopher Sandom and others, ‘Rewilding’ in David W Macdonald and Katherine J Willis (eds), Key Topics in Conservation Biology (Wiley-Blackwell 2013) vol 2, 430; Philip J Seddon and others, ‘Reversing Defaunation: Restoring Species in a Changing World’ (2014) 345 Science 406; Jamie Lorimer and others, ‘Rewilding: Science, Practice and Politics’ (2015) 40 Annual Review of Environment and Resources 39; Jens-Christian Svenning and others, ‘Science for a Wilder Anthropocene: Synthesis and Future Directions for Trophic Rewilding Research’ (2016) 113 Proceedings of the National Academy of Sciences of the USA 898; Richard T Corlett, ‘Restoration, Reintroduction, and Rewilding in a Changing World’ (2016) 31 Trends in Ecology & Evolution 453; Christopher Wolf and William J Ripple, ‘Rewilding the World’s Large Carnivores’ (2018) 5 Royal Society Open Science 172235; Andrea Perino and others, ‘Rewilding Complex Ecosystems’ (2019) 364 Science eaav5570; Nathalie Pettorelli, Sarah M Durant and Johan T du Toit (eds), Rewilding (CUP 2019); Paul Jepson and Cain Blythe, Rewilding: The Radical New Science of Ecological Recovery (Icon Books 2020); Jens-Christian Svenning, ‘Rewilding Should Be Central to Global Restoration Efforts’ (2020) 3 One Earth 657.

9

As summarised in Marcos Moleón and others, ‘Rethinking Megafauna’ (2020) 287 Proceedings of the Royal Society B 20192643, many studies using the term ‘megafauna’ do not define it, whereas others have employed various minimum sizes or weights, eg all terrestrial mammals with an average weight of ≥45 kg, or terrestrial herbivores of ≥40 or 100 kg and carnivores of ≥15 kg. Although the present study considers all the above as encompassed by the term ‘megafauna’, it does not adopt a minimum threshold, agreeing that ‘the concept of megafauna is far from simple, and, probably, it should not be simplified either’ (Moleón and others, 7). Incidentally, the term ‘megaherbivores’ generally denotes the very largest species, weighing ≥1,000 kg, whose bulk makes them largely immune from non-human predators; eg R Norman Owen-Smith, Megaherbivores: The Influence of Very Large Body Size on Ecology (CUP 1988).

10

Svenning (n 8) 657.

11

See s 2.

12

David W Macdonald and others, ‘Conserving Large Mammals: Are They a Special Case?’ in Macdonald and Willis (n 8) 277; William J Ripple and others, ‘Status and Ecological Effects of the World’s Largest Carnivores’ (2014) 343 Science 1241484; William J Ripple and others, ‘Collapse of the World’s Largest Herbivores’ (2015) 1 Science Advances e1400103; Michael J Noonan and others, ‘Effects of Body Size on Estimation of Mammalian Area Requirements’ (2020) 34 Conservation Biology 1017.

13

See all sources in (n 8) and, eg also Josh Donlan, ‘Re-Wilding North America’ (2005) 436 Nature 913; Josh Donlan and others, ‘Pleistocene Rewilding: An Optimistic Agenda for Twenty-First Century Conservation’ (2006) 168 The American Naturalist 660.

14

Philip J Seddon, W Maartin Strauss and John Innes, ‘Animal Translocations: What Are They and Why Do We Do Them?’ in John G Ewen and others (eds), Reintroduction Biology: Integrating Science and Management (Wiley-Blackwell 2012) 1; IUCN Species Survival Commission, Guidelines for Reintroductions and Other Conservation Translocations – Version 1.0 (IUCN SSC 2013); Philip J Seddon and Doug P Armstrong, ‘The Role of Translocation in Rewilding’ in Pettorelli and others (n 8) 303.

15

Erik Stokstad, ‘Bringing Back the Aurochs’ (2015) 350 Science 1144; Beth Shapiro, How to Clone a Mammoth: The Science of De-Extinction (Princeton University Press 2015); Jacob S Sherkow and Henry T Greely, ‘What If Extinction Is Not Forever?’ (2013) 340 Science 32; Philip J Seddon, Axel Moehrenschlager and John Ewen, ‘Reintroducing Resurrected Species: Selecting De-Extinction Candidates’ (2014) 29 Trends in Ecology and Evolution 140; Douglas J Richmond, Mikkel-Holger S Sinding and M Thomas P Gilbert, ‘The Potential and Pitfalls of De-Extinction’ (2016) 45 Zoologica Scripta 22; IUCN Species Survival Commission, IUCN SSC Guiding Principles on Creating Proxies of Extinct Species for Conservation Benefit – Version 1.0 (IUCN SSC 2016); Ben J Novak, ‘De-Extinction’ (2018) 9 Genes 548.

16

See the sources in (n 8) and (n 15), and also eg David Nogués-Bravo and others, ‘Rewilding is the New Pandora’s Box in Conservation’ (2016) 26 Current Biology 87; Matt W Hayward and others, ‘Reintroducing Rewilding to Restoration – Rejecting the Search for Novelty’ (2019) 233 Biological Conservation 255.

17

For example, Lorimer and others (n 8); Jepson and Blythe (n 8); Shapiro (n 15); Paul Jepson, ‘A Rewilding Agenda for Europe: Creating a Network of Experimental Reserves’ (2016) 39 Ecography 117; Paul Jepson and Frans Schepers, ‘Making Space for Rewilding: Creating an Enabling Policy Environment’ (2016) Policy Brief, doi 10.13140/RG.2.1.1783.1287; Nathalie Pettorelli and others, ‘Making Rewilding Fit for Policy’ (2018) 55 Journal of Applied Ecology 1114.

18

Corey A Salsberg, ‘Resurrecting the Woolly Mammoth: Science, Law, Ethics, Politics, and Religion’ (2000) 1 Stanford Technology Law Review 1; Paul A Rees, ‘Is There a Legal Obligation to Reintroduce Animal Species into Their Former Habitats?’ (2001) 35 Oryx 216; Alejandro E Camacho, ‘Assisted Migration: Redefining Nature and Natural Resource Law’ (2010) 27 Yale Journal on Regulation 171; Arie Trouwborst, ‘Managing the Carnivore Comeback: International and EU Species Protection Law and the Return of Lynx, Wolf and Bear to Western Europe’ (2010) 22 Journal of Environmental Law 347; Arie Trouwborst, ‘Transboundary Wildlife Conservation in a Changing Climate: Adaptation of the Bonn Convention on Migratory Species and its Daughter Instruments to Climate Change’ (2012) 4 Diversity 258; Aylwin Pilai and Danny Heptinstall, ‘Twenty Years of the Habitats Directive: A Case Study on Species Reintroduction, Protection and Management’ (2013) 15 Environmental Law Review 27; Norman F Carlin, Ilan Wurman and Tamara Zakim (2013) ‘How to Permit Your Mammoth: Some Legal Implications of “De-Extinction”’ (2013) 33 Stanford Environmental Law Journal 3; Alejandro E Camacho, ‘Going the Way of the Dodo: De-Extinction, Dualisms, and Reframing Conservation’ (2015) 92 Washington University Law Review 849; Arie Trouwborst, Miha Krofel and John DC Linnell, ‘Legal Implications of Range Expansions in a Terrestrial Carnivore: The Case of the Golden Jackal (Canis aureus) in Europe’ (2015) 24 Biodiversity and Conservation 2593; Miriam R Swedlow, ‘The Woolly Mammoth in the Room: The Patentability of Animals Brought Back from Extinction through Cloning and Genetic Engineering’ (2015) 11 Washington Journal of Law, Technology & Arts 183; Arie Trouwborst, ‘Law and Conservation Conflicts’ in Stephen M Redpath and others (eds), Conflicts in Conservation: Navigating towards Solutions (CUP 2015) 108; Jamie Lorimer, ‘Probiotic Legalities: De-Domestication and Rewilding before the Law’ in Irus Braverman (ed) Animals, Biopolitics, Law: Lively Legalities (Routledge 2016) 39; Kees Bastmeijer, ‘Ecological Restoration in International Biodiversity Law: A Promising Strategy to Address Our Failure to Prevent?’ in Michael JS Bowman, Peter Davies and Edward J Goodwin (eds), Research Handbook on Biodiversity and Law (Edward Elgar 2016) 387; SA Jeanetta Selier and others, ‘The Legal Challenges of Transboundary Wildlife Management at the Population Level: The Case of a Trilateral Elephant Population in Southern Africa’ (2016) 19 Journal of International Wildlife Law and Policy 101; Benjamin J Richardson, ‘The Emerging Age of Ecological Restoration Law’ (2016) 25 Review of European, Comparative and International Environmental Law 277; Erin Okuno, ‘Frankenstein’s Mammoth: Anticipating the Global Legal Framework for De-Extinction’ (2016) 43 Ecology Law Quarterly 581; Anastasia Telesetsky, An Cliquet and Afshin Akhtar-Khavari, Ecological Restoration in International Environmental Law (Routledge 2017); Norman Wagner and others, ‘De-Extinction, Nomenclature, and the Law’ (2017) 356 Science 1016; Phillipa C McCormack, ‘Conservation Introductions for Biodiversity Adaptation under Climate Change’ (2018) 7 Transnational Environmental Law 323; Andrew Blackmore and Arie Trouwborst, ‘Who Owns and Is Responsible for the Elephant in the Room? Management Plans for Free-Roaming Elephant in South Africa’ (2018) 48 Bothalia–African Biodiversity and Conservation a2271; Hendrik Schoukens, ‘Towards a Legally Enforceable Duty to Restore Endangered Species under EU Nature Conservation Law–On Wild Hamsters, the Rule of Law and Species Extinction’ in Jerzy Jendroska and Magdalena Bar (eds), Procedural Environmental Rights: Principle X in Theory and Practice (Intersentia 2018) 287; José V López-Bao and others, ‘Legal Obligations Regarding Species on the Verge of Extinction in Europe: Conservation, Restoration, Recolonization, Reintroduction’ (2018) 227 Biological Conservation 319; An Cliquet, ‘Ecological Restoration as a Legal Duty in the Anthropocene’ in Michelle Lim (ed), Charting Environmental Law Futures in the Anthropocene (Springer Nature 2019) 59; Aisling McMahon and David Doyle, ‘Patentability and De-Extinct Animals in Europe: The Patented Woolly Mammoth?’ (2020) 7 Journal of Law and the Biosciences lsaa017; Han Somsen and Arie Trouwborst, ‘Are Pioneering Coyotes, Jackals and Foxes Alien Species? Canid Colonists in the Changing Conservation Landscape of the Anthropocene’ (2020) 54 Oryx 235; Jessica Allen and others, ‘De-extinction, Regulation and Nature Conservation’ (2020) 32 Journal of Environmental Law 309; Arie Trouwborst and Andrew Blackmore, ‘Hot Dogs, Hungry Bears and Wolves Running Out of Mountain – International Wildlife Law and the Effects of Climate Change on Large Carnivores’ (2020) 23 Journal of International Wildlife Law and Policy 212; Arie Trouwborst and others, ‘Conservation Translocations and the Law’ in Martin Gaywood and others (eds), Conservation Translocations (CUP 2021, in press).

19

See s 3.

20

Megafauna extinctions have been much more numerous on land than at sea, and the marine environment has legal questions and frameworks of its own. Marine mammals are therefore beyond the present article’s scope. Parts of the analysis below may nevertheless be relevant to marine megafauna restoration efforts.

21

Svenning (n 8) 658.

22

Svenning and others (n 8); Perino and others (n 8); Pettorelli and others (n 8); Jepson and Blythe (n 8); MacDonald and others (n 12); Ripple and others 2014 (n 12); Ripple and others 2015 (n 12); Donlan and others (n 13); Richard T Corlett, ‘The Shifted Baseline: Prehistoric Defaunation in the Tropics and its Consequences for Biodiversity Conservation’ (2013) 163 Biological Conservation 13–21; Christopher J Sandom and others, ‘High Herbivore Density Associated with Vegetation Diversity in Interglacial Ecosystems’ (2014) 111 Proceedings of the National Academy of Sciences 4162; Yadvinder Malhi and others ‘Megafauna and Ecosystem Function from the Pleistocene to the Anthropocene’ (2016) 113 Proceedings of the National Academy of Sciences 838; Elisabeth S Bakker and others, ‘Combining Paleo-Data and Modern Exclosure Experiments to Assess the Impact of Megafauna Extinctions on Woody Vegetation’ (2016) 113 Proceedings of the National Academy of Sciences 847; Blaire van Valkenburgh and others, ‘The Impact of Large Terrestrial Carnivores on Pleistocene Ecosystems’ (2016) 113 Proceedings of the National Academy of Sciences 862; Christopher E Doughty and others, ‘Global Nutrient Transport in a World of Giants’ (2016) 113 Proceedings of the National Academy of Sciences 868; Felisa A Smith and others ‘Megafauna in the Earth System’ (2016) 39 Ecography 99; Christopher E Doughty, Søren Faurby and Jens-Christian Svenning, ‘The Impact of the Megafauna Extinctions on Savannah Woody Cover in South America’ (2016) 39 Ecography 213; Mauro Galetti and others ‘Ecological and Evolutionary Legacy of Megafauna Extinctions’ (2018) 93 Biological Reviews 845; Erick J Lundgren and others, ‘Introduced Herbivores Restore Late Pleistocene Ecological Functions’ (2020) 117 Proceedings of the National Academy of Sciences 7871; Erick J Lundgren and others, ‘Functional Traits of the World’s Late Quaternary Large-Bodied Avian and Mammalian Herbivores’ (2021) 8 Scientific Data 17.

23

ibid.

24

Svenning (n 8) 658.

25

Ripple and others 2014 (n 12); Ripple and others 2015 (n 12); Søren Faurby and Jens-Christian Svenning, ‘Historic and Prehistoric Human-Driven Extinctions Have Reshaped Global Mammal Diversity Patterns’ (2015) 21 Diversity and Distributions 1155; William J Ripple and others, ‘Saving the World’s Terrestrial Megafauna’ (2016) 66 BioScience 807.

26

Björn Kurtén, Pleistocene Mammals of Europe (Routledge 1968/2017); Paul S Martin, Twilight of the Mammoths: Ice Age Extinctions and Rewilding America (University of California Press 2005); Felisa A Smith and others, ‘The evolution of maximum body size of terrestrial mammals’ (2010) 330 Science 1216; Faurby and Svenning (n 25); Ross DE MacPhee, End of the Megafauna: The Fate of the World’s Hugest, Fiercest, and Strangest Animals (Norton & Company 2019).

27

Jeheskel Shoshani, ‘Understanding Proboscidean Evolution: A Formidable Task’ (1998) 13 Trends in Ecology and Evolution 480.

28

Chris D Thomas, Inheritors of the Earth: How Nature is Thriving in an Age of Extinction (Penguin 2018) 36.

29

MacPhee (n 26) offers an accessible overview of these extinctions and illustrated descriptions of species involved.

30

ibid xii.

31

Alfred R Wallace, The Geographical Distribution of Animals (Harper and Brothers 1876) 150.

32

Malhi and others (n 22); Smith and others (n 22); Martin (n 26); MacPhee (n 26); Faurby and Svenning (n 25); Anthony D Barnosky and others, ‘Assessing the Causes of Late Pleistocene Extinctions on the Continents’ (2004) 306 Science 70; David A Burney and Timothy F Flannery, ‘Fifty Millennia of Catastrophic Extinctions After Human Contact’ (2005) 20 Trends in Ecology and Evolution 395; Christopher Sandom and others, ‘Global Late Quaternary Megafauna Extinctions Linked to Humans, Not Climate Change’ (2014) 281 Proceedings of the Royal Society B 20133254; Rodolfo Dirzo and others, ‘Defaunation in the Anthropocene’ (2014) 345 Science 401; Anthony J Stuart, ‘Late Quaternary Megafaunal Extinctions on the Continents: A Short Review’ (2015) 50 Geological Journal 338; Sara Varela and others, ‘Differential Effects of Temperature Change and Human Impact on European Late Quaternary Mammalian Extinctions’ (2015) 21 Global Change Biology 1475; Bernardo BA Araujo and others, ‘Bigger Kill than Chill: The Uneven Roles of Humans and Climate on Late Quaternary Megafaunal Extinctions’ (2017) 431(B) Quaternary International 216.

33

Alfred R Wallace, The World of Life: A Manifestation of Creative Power, Directive Mind and Ultimate Purpose (Chapman and Hall 1911) 246; and at 249: ‘It is therefore certain, that, so soon as man possessed weapons and the use of fire, his power of intelligent combination would have rendered him fully able to kill or capture any animal that has ever lived upon the earth; and as the flesh, bones, hair, horns, or skins would have been of use to him, he would certainly have done so even had he not the additional incentive that in many cases the animals were destructive to his crops or dangerous to his children or to himself. The numbers he would be able to destroy, especially of the young, would be an important factor in the extermination of many of the larger species.’

34

Richard G. Klein, The Human Career: Human Biological and Cultural Origins (2nd edn, University of Chicago Press 1999) 564.

35

Martin (n 26) 50.

36

Ross Barnett, The Missing Lynx: The Past and Future of Britain’s Lost Mammals (Bloomsbury Wildlife 2019) 27.

37

James B MacKinnon, The Once and Future World: Nature As It Was, As It Is, As It Could Be (Vintage Canada 2014) 65–6.

38

ibid 178.

39

See the sources mentioned in (n 32).

40

MacKinnon (n 37) 90 (emphasis in original).

41

John Alroy, ‘Putting North America’s End-Pleistocene Megafaunal Extinction in Context’ in Ross DE MacPhee (ed) Extinctions in Near Time (Springer 1999) 105.

42

Sandom and others (n 32).

43

MacDonald and others (n 12); Ripple and others 2014 (n 12); Ripple and others 2015 (n 12); Dirzo and others (n 32); Arian D Wallach and others, ‘Invisible Megafauna’ (2018) 32 Conservation Biology 962.

44

MacKinnon (n 37) 62.

45

‘Us and killer asteroids.’ ibid 63.

46

Martin (n 26) 1–2.

47

For example, Kurtén (n 26).

48

MacKinnon (n 37) 141.

49

Dirzo and others (n 32).

50

Daniel Pauly, ‘Anecdotes and the Shifting Baseline Syndrome of Fisheries’ (1995) 10 Trends in Ecology & Evolution 430; see also Sarah Papworth and others, ‘Evidence for Shifting Baseline Syndrome in Conservation’ (2009) 2 Conservation Letters 93; Frans Vera, ‘The Shifting Baseline Syndrome in Restoration Ecology’ in Marcus Hall (ed) Restoration and History: The Search for a Usable Environmental Past (Routledge 2010) 98.

51

Jepson and Blythe (n 8) 1.

52

Raymond A Rogers, Nature and the Crisis of Modernity: A Critique of Contemporary Discourse on Managing the Earth (Black Rose Books 1994).

53

Thomas (n 28) 39.

54

ibid 40.

55

Richard J Hobbs, Eric Higgs and James A Harris, ‘Novel Ecosystems: Implications for Conservation and Restoration’ (2009) 24 Trends in Ecology & Evolution 599; Thomas (n 28).

56

Edward O Wilson, Half-Earth: Our Planet’s Fight for Life (Liveright Publishing 2016); Eric Dinerstein and others, ‘An Ecoregion-Based Approach to Protecting Half the Terrestrial Realm’ (2017) 67 BioScience 534; Jonathan Baillie and Ya-Ping Zhang, ‘Space for Nature’ (2018) 361 Science 1051; Heather M Tallis and others, ‘An Attainable Global Vision for Conservation and Human Well-Being’ (2018) 16 Frontiers in Ecology and the Environment 563; Eric Dinerstein and others, ‘A Global Deal for Nature: Guiding Principles, Milestones, and Targets’ (2019) 5 Science Advances eaaw2869; Anthony Waldron and others, Protecting 30% of the Planet for Nature: Costs, Benefits and Economic Implications: Working Paper Analysing the Economic Implications of the Proposed 30% Target for Areal Protection in the Draft Post-2020 Global Biodiversity Framework (Campaign for Nature 2020); David Leclère and others, ‘Bending the Curve of Terrestrial Biodiversity Needs an Integrated Strategy’ (2020) 585 Nature 551; UNEP (n 6) 113.

57

IPBES (n 2) 33; Sandra Díaz and others, ‘Pervasive Human-Driven Decline of Life on Earth Points to the Need for Transformative Change’ (2019) 366 Science 1327.

58

Guillaume Chapron and others, ‘Recovery of Large Carnivores in Europe’s Modern Human-Dominated Landscapes’ (2014) 346 Science 1517.

59

For example, Céline Albert, Gloria M Luqe and Franck Courchamp, ‘The Twenty Most Charismatic Species’ (2018) 13 PLoS One e0199149.

60

Svenning (n 8) 657.

61

ibid.

62

MacDonald and others (n 12); Ripple and others 2014 (n 12); Ripple and others 2015 (n 12); Dirzo and others (n 32); Wallach and others (n 43).

63

David Garshelis and Robert Steinmetz, ‘Ursus thibetanus (Amended Version of 2016 Assessment)’, The IUCN Red List of Threatened Species (2020) e.T22824A166528664.

64

For example, Evelyne Crégut-Bonnoure, ‘The Saalian Ursus thibetanus from France and Italy’ (1997) 30 Geobios 285.

65

Paul S Martin and David A Burney, ‘Bring Back the Elephants!’ (1999) 9 Wild Earth 57; Martin (n 26) 208–11; Christy Williams and others, ‘Elephas maximus’, The IUCN Red List of Threatened Species (2020) e.T7140A45818198; see also David Bowman, ‘Bring Elephants to Australia?’ (2012) 482 Nature 30.

66

Donlan and others (n 13) 662, 669; cheetahs are listed as ‘vulnerable’: Sarah Durant and others, ‘Acinonyx jubatus’, The IUCN Red List of Threatened Species (2015) e.T219A50649567.

67

Joris PGM Cromsigt and others, ‘Trophic Rewilding as a Climate Change Mitigation Strategy?’ (2018) 373 Philosophical Transactions of the Royal Society B 20170440; Fabio Berzaghi and others, ‘Carbon Stocks in Central African Forests Enhanced by Elephant Disturbance’ (2019) 12 Nature Geoscience 725; Christopher J Sandom and others, ‘Trophic Rewilding Presents Regionally Specific Opportunities for Mitigating Climate Change’ (2020) 375 Philosophical Transactions of the Royal Society B 20190125.

68

Cromsigt and others (n 67); Sandom and others (ibid); Christopher N Johnson and others, ‘Can Trophic Rewilding Reduce the Impact of Fire in a More Flammable World?’ (2018) 373 Philosophical Transactions of the Royal Society B 20170443.

69

Christopher E Doughty (2020) ‘Megafauna Decline Have Reduced Pathogen Dispersal Which May Have Increased Emergent Infectious Diseases’ (2020) 43 Ecography 1107.

70

Tristan T Derham and others, ‘Hope and Caution: Rewilding to Mitigate the Impacts of Biological Invasions’ (2018) 373 Philosophical Transactions of the Royal Society B 20180127.

71

Jepson and Blythe (n 8).

72

Martin (n 26) 202.

73

Peter A Lindsey and others, ‘Relative Efforts of Countries to Conserve World’s Megafauna’ (2017) 10 Global Ecology and Conservation 243; see also s 4.2.

74

See the sources in (n 18); also Benjamin J Richardson, Time and Environmental Law: Telling Nature’s Time (CUP 2017).

75

Ripple and others (n 25); Arie Trouwborst and others, ‘International Wildlife Law: Understanding and Enhancing Its Role in Conservation’ (2017) 67 BioScience 784; Arie Trouwborst, ‘Global Large Carnivore Conservation and International Law’ (2015) 24 Biodiversity and Conservation 1567; Arie Trouwborst, ‘Global Large Herbivore Conservation and International Law’ (2019) 28 Biodiversity and Conservation 3891.

76

Benjamin J Richardson, ‘Reclaiming Nature: Eco-Restoration of Liminal Spaces’ (2016) 2 Australian Journal of Environmental Law 1, 2.

77

Bastmeijer (n 18); Telesetsky and others (n 18); Schoukens (n 18); Cliquet (n 18); Royal C Gardner, ‘Rehabilitating Nature: A Comparative Review of Legal Mechanisms that Encourage Wetland Restoration Efforts’ (2003) 52 Catholic University Law Review 573.

78

CBD (n 5) art 8(f).

79

Convention for the Conservation of the Biodiversity and the Protection of Priority Wilderness Areas in Central America (1992) art 24.

80

Han Somsen and Arie Trouwborst, ‘Loss of Biosphere Integrity (Biodiversity Loss and Extinctions)’ in Duncan French and Louis Kotzé (eds), Research Handbook on Law, Governance and Planetary Boundaries (Edward Elgar 2021) 221.

81

Protocol on Conservation and Sustainable Use of Biological and Landscape Diversity to the Framework Convention on the Protection and Sustainable Development of the Carpathians (2003).

82

ibid art 4 (emphasis added).

83

ibid art 8(2) (emphasis added).

84

ibid art 3(r).

85

Kajetan Perzanowski and Wanda Olech, ‘A Future for European Bison Bison bonasus in the Carpathian Ecoregion?’ (2007) 13 Wildlife Biology 108; Tobias Kuemmerle and others, ‘European Bison Habitat in the Carpathian Mountains’ (2010) 143 Biological Conservation 908; Rewilding Europe, ‘Largest Ever Bison Reintroduction in Southern Carpathians Boosts Population by 23 Animals’ (2018) <https://rewildingeurope.com/news/largest-ever-bison-reintroduction-in-southern-carpathians-boosts-population-by-23-animals/> accessed 22 July 2021.

86

The Protocol’s stated objective is ‘to enhance the conservation, restoration and sustainable use of biological and landscape diversity of the Carpathians’ (art 1(1)).

87

See eg, Kurtén (n 26); Stuart (n 32); and also Attila Németh and others, ‘Holocene Mammal Extinctions in the Carpathian Basin: A Review’ (2016) 47 Mammal Review 38.

88

Carpathian Convention COP Decision COP6/5 (2020) para 6 (emphasis added).

89

For example, Daniel J Thompson and Jonathan A Jenks, ‘Dispersal Movements of Subadult Cougars from the Black Hills: The Notions of Range Expansion and Recolonization’ (2010) 1 Ecosphere 1.

90

Trouwborst 2010 (n 18); Chapron and others (n 58). The wolf comeback is still controversial—but the point is that its active reintroduction would have been more so, let alone introducing it beyond its native range, eg in Australia or South America.

91

Trouwborst ibid; Arie Trouwborst, ‘Living with Success – and with Wolves: Addressing the Legal Issues Raised by the Unexpected Homecoming of a Controversial Carnivore’ (2014) 23 European Energy and Environmental Law Review 89.

92

James W Hody and Roland Kays, ‘Mapping the Expansion of Coyotes (Canis latrans) across North and Central America’ (2018) 759 ZooKeys 81.

93

Trouwborst and others 2015 (n 18); Robert Rutkowski and others, ‘A European Concern? Genetic Structure and Expansion of Golden Jackals (Canis aureus) in Europe and the Caucasus’ (2015) 10 PLoS One e0141236.

94

Trouwborst and others ibid; Somsen and Trouwborst (n 18); Trouwborst and Blackmore (n 18).

95

CBD COP Decision VI/23 (2002) Annex.

96

Regulation No 1143/2014 of 22 October 2014 on the Prevention and Management of the Introduction and Spread of Invasive Alien Species [2014] OJ L317/35.

97

ibid art 2(1); art 3(1) defines an ‘alien species’ as a specimen ‘introduced outside its natural range’; art 3(7) clarifies that ‘introduction’ is understood as ‘movement, as a consequence of human intervention’.

98

ibid art 2(2)(a).

99

Council Directive 92/43/EEC of 21 May 1992 on the Conservation of Natural Habitats and of Wild Fauna and Flora [1992] OJ L206/7.

100

Convention on the Conservation of Migratory Species of Wild Animals (1979) 1651 UNTS 333.

101

See also Trouwborst 2012 (n 18); Trouwborst and others 2015 (n 18); Trouwborst and Blackmore (n 18).

102

Habitats Directive (n 99) arts 12–6.

103

European Commission, ‘Guidance Document on the Strict Protection of Animal Species of Community Interest under the Habitats Directive 92/43/EEC’ (2007) para 19.

104

CJEU Case C-88/19 Asociatia ‘Alianta pentru combaterea abuzurilor’ [2020] OJ C 271/12.

105

CMS (n 100) art I(1)(f).

106

ibid art I(1)(c)(4).

107

CMS COP Resolution 12.21 (2017) para 9; see also Trouwborst 2012 (n 18); Trouwborst and Blackmore (n 18).

108

CBD (n 5).

109

ibid art 9(c).

110

ibid art 8(h).

111

IUCN (n 14) 2–3; assisted colonisation is also known as ‘assisted migration’, ‘managed relocation’ and ‘benign introduction’.

112

Trouwborst and others 2021 (n 18).

113

Rees (n 18); Trouwborst and others 2021 (n 18).

114

CMS (n 100) art V(5)(g).

115

Convention on the Conservation of European Wildlife and Natural Habitats (1979) ETS 104, art 11(2)(a).

116

Carpathian Biodiversity Protocol (n 81) art 12(3).

117

See (n 83).

118

For example, John DC Linnell and others, ‘Recovery of Eurasian Lynx in Europe: What Part has Reintroduction Played?’ in Matt W Hayward and Michael J Somers (eds), Reintroduction of Top-Order Predators (Blackwell 2009) 72.

119

For example, Chris Walzer and others, ‘Przewalski’s Horse Reintroduction to Mongolia: Status and Outlook’ (2012) 13 WAZA Magazine 3.

120

For example, Mark R Stanley Price, ‘Reintroduction as an Antelope Conservation Solution’ in Jakob Bro-Jørgensen and David P Mallon (eds), Antelope Conservation: From Diagnosis to Action (John Wiley & Sons 2016) 217.

121

For example, John B Sale and Samar Singh, ‘Reintroduction of Greater Indian Rhinoceros into Dudhwa National Park’ (1987) 21 Oryx 81; Wayne L Linklater, ‘Guidelines for Large Herbivore Translocation Simplified: Black Rhinoceros Case Study’ (2011) 48 Journal of Applied Ecology 493.

122

Cindy M Hurtado and others, ‘Spatial Patterns of the First Groups of Collared Peccaries (Pecari tajacu) Reintroduced in South America’ (2020) 61 Tropical Ecology 400.

123

For example, Robert L Beschta and William J Ripple, ‘Riparian Vegetation Recovery in Yellowstone: The First Two Decades after Wolf Reintroduction’ (2016) 198 Biological Conservation 93.

124

Pierre-Yves Quenette and others, ‘Preliminary Results of the First Transplantation of Brown Bears in the French Pyrenees’ (2001) 12 Ursus 115.

125

López-Bao and others (n 18); Arie Trouwborst ‘The EU Habitats Directive and Wolf Conservation and Management on the Iberian Peninsula: A Legal Perspective’ (2014) 26 Galemys: Spanish Journal of Mammalogy 15.

126

IUCN (n 14) 13.

127

ibid 13–14; for an overview and discussion see Trouwborst and others 2021 (n 18).

128

ibid.

129

ibid.

130

ibid.

131

Camacho 2010 (n 18) 244.

132

Pettorelli and others (n 17) 1121.

133

Kurtén (n 26).

134

Habitats Directive (n 99) arts 2(2) and 1(g).

135

European Environment Agency, State of Nature in the EU: Results from Reporting under the Nature Directives 2013–2018 (Publications Office of the European Union 2020).

136

Words used in the European Environment Agency’s press release of the report, ‘State of Nature in Europe – A Health Check’, 23 November 2020 <https://www.eea.europa.eu/themes/biodiversity/state-of-nature-in-the-eu> accessed 22 July 2021.

137

Habitats Directive (n 99) art 22(a).

138

CJEU Case C-127/02 Waddenvereniging and Vogelbescherming [2004] ECR I-7405 para 61.

139

Habitats Directive (n 99) art 6(3).

140

On tensions between rewilding and the Habitats Directive see also Jepson and Schepers (n 17).

141

Bern Convention (n 115) art 11(2)(a).

142

ibid art 4; see also Arie Trouwborst, Obligations of Bern Convention Parties regarding the Conservation of Candidate and Adopted Emerald Network Sites: A Legal Analysis, Bern Convention Doc T-PVS/PA (2020) 7.

143

Tigers disappeared from Turkey and the Caucasus only in the first half of the 20th century; on the prospects of a return to such erstwhile range, see eg Igor E Chestin and others, ‘Tiger Re-Establishment Potential to Former Caspian Tiger (Panthera tigris virgata) Range in Central Asia’ (2017) 205 Biological Conservation 42. It can be argued that Asiatic black bears are also within the scope of Appendix II, which lists ‘all species’ of Ursidae.

144

CMS (n 100) art 1(c)(4).

145

ibid art V(5)(g).

146

See also Trouwborst 2012 (n 18).

147

Mayank Aggarwal, ‘India Considers Bringing Back the Cheetah, Even as Lions and Other Species Wait for Conservation Attention’ (2020) Mongabay <https://india.mongabay.com/2020/01/india-considers-bringing-back-the-cheetah-even-as-lions-and-other-species-wait-for-conservation-attention/> accessed 22 July 2021; Esha Roy, ‘70 Years after Big Cat’s Extinction, India Prepares to Welcome Cheetahs from Africa’, Indian Express, 21 March 2021 <https://indianexpress.com/article/india/india-imports-african-cheetahs-big-cat-locally-extinction-7237807/> accessed 22 July 2021.

148

Supreme Court of India, Centre for Environmental Law, WWF v Union of India et al, 15 April 2013.

149

ibid 28 January 2020.

150

IUCN (n 14) viii.

151

CBD COP (n 95).

152

ibid Guiding Principle 10.

153

For example, (Revised) African Convention on the Conservation of Nature and Natural Resources (2003) art IX(2)(h): ‘strictly control the intentional … introduction, in any area, of species which are not native to that area’; Protocol to the Nairobi Convention Concerning Protected Areas and Wild Fauna and Flora in the Eastern African Region (1985) art 7: ‘take all appropriate measures to prohibit the intentional or accidental introduction of alien or new species which may cause significant or harmful changes to the Eastern African region’; Bern Convention (n 115) art 11(2)(b): ‘strictly control the introduction of non-native species’; Protocol on the Implementation of the Alpine Convention of 1991 Relating to Nature Protection and Landscape Conservation (1994) art 17: ‘assure that no wild animal or plant species are introduced into a region that were not previously present naturally for a verifiable historic period’.

154

Donlan and others (n 13); Martin (n 26).

155

Bowman (n 65); William F Laurence, ‘The Case for Introducing Rhinos to Australia’ (2018) The Conversation, https://theconversation.com/the-case-for-introducing-rhinos-to-australia-99585.

156

CBD COP (n 95).

157

McCormack (n 18).

158

IUCN (n 14) 2.

159

Stephen T Jackson and Richard J Hobbs, ‘Ecological Restoration in the Light of Ecological History’ (2009) 325 Science 567; Philip J Seddon, ‘From Reintroduction to Assisted Colonization: Moving Along the Conservation Translocation Spectrum’ (2010) 18 Restoration Ecology 796; Dolly Jørgensen, ‘What’s History Got to Do with It? A Response to Seddon’s Definition of Reintroduction’ (2011) 19 Restoration Ecology 705; Sarah E Dalrymple and Axel Moehrenschlager, ‘“Words Matter.” A Response to Jørgensen’s Treatment of Historic Range and Definitions of Reintroduction’ (2013) 21 Restoration Ecology 156.

160

IUCN Species Survival Commission in collaboration with the Commission on Ecology, and the Commission on Environmental Policy, Law and Administration, The IUCN Position Statement on Translocation of Living Organisms (IUCN 1987) 1 (emphasis added).

161

IUCN/SSC Re-Introduction Specialist Group, Guidelines for Re-Introductions (IUCN 1998) 6 (emphasis added).

162

IUCN SSC Invasive Species Specialist Group, IUCN Guidelines for the Prevention of Biodiversity Loss Caused by Alien Invasive Species (IUCN 2000) (emphasis added).

163

See s 3.1; see also Trouwborst and Blackmore (n 18); Arie Trouwborst, ‘The Habitats Directive and Climate Change: Is the Law Climate-Proof?’ in Charles-Hubert Born and others (eds), The Habitats Directive in its EU Environmental Law Context (Routledge 2015) 303.

164

Jedediah F Brodie and others, ‘Global Policy for Assisted Colonization of Species’ (2021) 372 Science 456; Trouwborst and others 2021 (n 18).

165

Jepson (n 17) 120–21; Jepson and Schepers (n 17) 5; Lorimer (n 18).

166

Jepson and Blythe (n 8) 140–41.

167

The IUCN guidelines on this issue (IUCN (n 15) 1) stress that this term is ‘misleading in its implication that extinct species, species for which no viable members remain, can be resurrected in their genetic, behavoural and physiological entirety’—hence, the guidelines prefer the term ‘proxies for de-extinct species’.

168

See the majority of the sources in (n 18); also Han Somsen, ‘Towards a Law of the Mammoth? Climate Enhancement in EU Environmental Law’ (2016) 7 European Journal of Risk Regulation 109.

169

Carlin and others (n 18); Swedlow (n 18); McMahon and Doyle (n 18).

170

Camacho 2015 (n 18); Okuno (n 18); Wagner and others (n 18); Allen and others (n 18); Somsen (n 168).

171

For example, Okuno (n 18) 598–99; Markku Oksanen and Timo Vuorisalo, ‘De-Extinct Species as Wildlife’ (2017) 3 Trace: Finnish Journal for Human-Animal Studies 4.

172

Camacho 2015 (n 18) 890.

173

IUCN (n 15) 1.

174

Naturally, such escapes tend to be viewed initially through the legal prism of tortious or criminal liability and alien species regulations rather than being considered a potential conservation gain.

175

Martin (n 26) 198.

176

See eg Jorge Cassinello and others, ‘Range Expansion of an Exotic Ungulate (Ammotragus lervia) in Southern Spain: Ecological and Conservation Concerns’ (2004) 13 Biodiversity and Conservation 851.

177

Amanda L Subalusky and others, ‘Potential Ecological and Socio-Economic Effects of a Novel Megaherbivore Introduction: The Hippopotamus in Colombia’ (2019) 55 Oryx 105.

178

Erick J Lundgren and others, ‘Introduced Megafauna are Rewilding the Anthropocene’ (2018) 41 Ecography 857.

179

ibid; Subalusky and others (n 177); Lundgren and others 2020 (n 22).

180

Jorge Cassinello and others, ‘Ammotragus lervia’, The IUCN Red List of Threatened Species (2008) e.T1151A3288917.

181

For example, Cassinello and others (n 176); Mariana Fernández-Olalla and others, ‘Threat or Opportunity? Browsing Preferences and Potential Impact of Ammotragus lervia on Woody Plants of a Mediterranean Protected Area’ (2016) 129 Journal of Arid Environments 9.

182

Corey JA Bradshaw and others, ‘Conservation Value of Non-Native Banteng in Northern Australia’ (2006) 20 Conservation Biology 1306.

183

Penny Gardner and others, ‘Bos javanicus’, The IUCN Red List of Threatened Species (2016) e.T2888A46362970.

184

Bradshaw and others (n 182).

185

ibid.

186

ibid 1309–10.

187

See also Wallach and others (n 43).

188

Trouwborst 2015 (n 18).

189

For example, Thomas Merckx and Henrique M Pereira, ‘Reshaping Agri-Environmental Subsidies: From Marginal Farming to Large-Scale Rewilding’ (2015) 16 Basic and Applied Ecology 95.

190

Jepson (n 17) 121.

191

See eg Dhoya Snijders, ‘Shifting Species in South Africa: Wildlife Policy, Rural Consequences’ (PhD thesis, Vrije Universiteit Amsterdam 2015).

192

As Pettorelli and others (n 17) 1122 observe, megafauna rewilding projects on US public lands may face ‘conflict with private ranchers holding grazing permits, who can hold strongly negative attitudes towards any wildlife species they perceive as predators of livestock or competitors for grazing resources’.

193

Guillaume Chapron, Yaffa Epstein and José Vicente López-Bao, ‘A Rights Revolution for Nature’ (2019) 363 Science 1392.

194

John Hadley, Animal Property Rights: A Theory of Habitat Rights for Wild Animals (Lexington 2016); Karen Bradshaw, Wildlife as Property Owners: A New Conception of Animal Rights (University of Chicago Press 2020).

195

Somsen and Trouwborst (n 80).

196

For readers wishing to explore in greater depth how compelling the arguments involved really are—or who are simply curious to know more—the footnotes offer plenty pointers to further reading.

197

MacKinnon (n 37) 19.

198

Jepson and Blythe (n 8) 148.

199

Lorimer and others (n 8) 55.

200

George Monbiot, Feral: Rewilding the Land, Sea and Human Life (Penguin 2013) 127.

201

Elizabeth Fisher, ‘Environmental Law and Populism’ (2019) 31 JEL 386.

202

For example, Hugh AH Jansman, ‘Animal Conservation in the Twenty-First Century’ in Bernice Bovenkerk and Jozef Keulartz (eds), Animals in Our Midst: The Challenges of Co-existing with Animals in the Anthropocene (Springer 2021) 27, 36–40; Jepson and Blythe (n 8) 119; also Lorimer (n 18).

203

Martin (n 26) 184.

204

Sophie Monsarrat and Jens-Christian Svenning, ‘Using Recent Baselines as Benchmarks for Megafauna Restoration Places an Unfair Burden on the Global South’ (13 March 2021) bioRxiv. doi:10.1101/2021.03.13.435233 (preprint).

205

Tim Flannery, Europe: The First 100 Million Years (Penguin 2019) 195.

206

For vivid descriptions and statistics of what coexistence with such animals can entail, see James Clarke, Save Me from the Lion’s Mouth: Exposing Human-Wildlife Conflict in Africa (Struik Nature 2012).

207

See eg Arie Trouwborst, Floor M Fleurke and John DC Linnell, ‘Norway’s Wolf Policy and the Bern Convention on European Wildlife: Avoiding the “Manifestly Absurd”’ (2017) 20 Journal of International Wildlife Law and Policy 155.

208

Including the present author.

209

MacKinnon (n 37) 20–21 cites biologist Loren McClenachan as saying she no longer looks with the same eyes: ‘It’s like there’s all these ghosts lurking around’; also Richardson (n 74) 187–91.

210

Martin (n 26) 200.

211

Jepson and Blythe (n 8).

212

Henry D Thoreau, The Journal, 1837-1861 (NYRB Classics 2011) 373.

213

Also Martin (n 26) 56–57.

214

For example, Donlan and others (n 13).

215

Monbiot (n 200) 89.

ACKNOWLEDGEMENTS

Helpful suggestions for improvement from two anonymous reviewers are gratefully acknowledged.

Conflict of interest statement. The author has no conflict of interest to declare.