How Rewilding Works

First published in Sanctuary Asia, Vol. 43 No. 10, October 2023

By Magnus Sylvén and Karl Wagner

To restore stability to our planet, we must restore its biodiversity, the very thing that we’ve removed. It’s the only way out of this crisis we’ve created – we must rewild the world.
Sir David Attenborough, ‘A Life on Our Planet’

Ancient forests that stretch across whole continents. Rivers teeming with fish, so dense that you cannot see the bottom. Herds of several million wildebeest that blanket the horizon. Flocks of birds, so large they block out the sun for hours. These visions of nature seem like something out of a fantasy novel, but they describe sights that would have been readily visible only a few hundred years ago. Since the onset of the Industrial Revolution, the scale of natural destruction by humans has been nearly unfathomable. If this continues unabated, the future of the natural world, as we know it, and with it the future of human civilisation, is at stake.

Overfishing continues to be a key threat for northern bluefin tuna Thunnus orientalis populations. Photo: Solvin Zankl/Wild Wonders of Europe.

Why Do We Need Nature?

Almost every day we learn about new challenges: loss of tropical forests and coral reefs, newly-designated endangered species, declining wildlife populations, and, especially, how climate change is wreaking havoc on land and in the sea. Hurricanes, flooding, wildfires, extreme temperatures, and droughts, often with very serious, negative impacts on people and their livelihoods, especially in the less affluent parts of the world, are becoming regular sights in the news.

The loss of ecosystem functionality (often referred to as ‘ecological integrity’), is the degradation of the web of life once species are lost or decline in numbers. The level that we are witnessing is staggering and should be setting off all alarm bells. Studies show that only around three per cent of land and sea (97 per cent of the ocean is impacted by ‘some kind of fishing’) could be seen as still ecologically functional.

Humans tend to forget how much their life, health, well-being and economic prosperity depend on what nature provides. Agriculture is made possible through a stable climate and without native pollinators, harvests would shrink and maybe entirely falter. Functioning ecosystems provide surface and groundwater, and are the best protection from floods and droughts. These are but a few services that functioning ecosystems provide. Despite this, there is
a tendency to only understand and value them once they are diminished or have disappeared entirely.

If we treat nature as a partner and let it flourish by giving it enough peace and space from human exploitation, then it becomes our most important ally for the survival and well-being of urban and rural communities, and human civilisation as a whole.

Rewilding is the philosophy of treating nature as a partner and ally. It is about allowing the restoration of intact, functional nature and restoring the natural safety nets human communities depend on in their daily life. It is about giving nature the space it needs; letting nature take care of itself; enabling natural processes to shape land and sea; repairing damaged ecosystems; and restoring degraded landscapes and seascapes. Often, rewilding requires that the comeback of missing key species, such as bison, elephants, tigers, sea otters, and salmon, is promoted and facilitated. These species, often referred to as ‘keystone species’, play a critical role in how the ecosystems in which they act function and determine the presence of many other species as well. Ecosystems function as a complex web of life, with the actions of one species creating a cascading effect across the food web, that all manner of other species rely on to survive.

A key tool to rebuild marine life is to establish no-take – or ‘replenishment’ – fishing zones. Photo: Srikanth Mannepuri/Sanctuary Photolibrary.
The Power of No-Take Fishing Zones
Ecological extinction caused by overfishing precedes all other pervasive human disturbance to marine ecosystems, including pollution, degradation of water quality, and – until now – anthropogenic climate change. A key tool to rebuild marine life, including fish populations, is to establish no-take – or ‘replenishment’ – fishing zones. No-take marine reserves are the most effective way of protecting the ocean: the biomass of whole fish assemblages in marine reserves is, on average, 670 per cent larger than in adjacent unprotected areas, and the density and individual size of all taxa (not only fish) are higher: 166 per cent and 28 per cent, respectively. Cascading effects within no-take zones also promote natural processes (for example, natural grazing or recruitment rates) responsible for maintaining resistance or resilience to various natural and human threats and stresses.
In numerous examples, the increase in target predatory species results in decreases of grazing species, which are often their prey. The reduction in grazers, in turn, affects in a positive way the benthic (the bottom-most region of a water body) community structure.
Through spill-over effects and enhanced recruitment of fish and other commercially valuable species, no-take zones have been shown to produce numerous social and economic benefits for local communities, supporting sustainable, local fish yields as well as profits in the surrounding areas. No-take zones can also generate or enhance alternative livelihoods, such as through tourism revenues.
It has been concluded that “no-take zones may be one of the only tools at our disposal to alleviate the effects of climate change on coral reefs and other marine ecosystems”. The comeback of marine fish populations will also have a tremendously positive impact on climate change, facilitating the capture of huge amounts of excess carbon dioxide through trophic rewilding and Animating the Carbon Cycle

Turning Theory into Practice

Although rewilding as a concept is relatively new in theory and practice, proof of the potential positive impacts are already starting to accumulate. There are numerous examples of the success of rebuilding populations of key animal species across Asia, Africa, Australia, Europe, and the Americas. However, it takes longer to evaluate the positive impacts on overall nature and climate. For that reason, we present two examples of conservation action – one in the marine environment and the second on land – that are not referred to as ‘rewilding’, but in practice are.

Since rewilding is about “shaping new opportunities for local livelihoods and the wider economy anchored in a more secure future with healthy nature and much higher climate resilience”, we also must understand why the voices of local and Indigenous communities must be heard and their needs and concerns addressed.

The Global Rewilding Alliance
Anchored in the Global Charter for Rewilding the Earth: Advancing nature-based solutions to the extinction and climate crises, the Global Rewilding Alliance (GRA) was founded by The Wild Foundation and Re:wild in 2020. We base our work on 12 guiding principles outlined in the Charter.
The network of currently 140+ organisations works across Africa, Asia, Australia, Europe, Latin America, North America and globally to rewild more than 160 million hectares of land and sea in over 90 countries. As of today, we have 17 members in India. In addition to the Sanctuary Nature Foundation, the list of organisations includes the Wildlife Conservation Trust, Wildlife Trust of India, Dusty Foot Foundation, River Otter Conservancy, India Climate Collaborative, Tata Trusts, Balipara Foundation, iamgurgaon, and Walk for Water.
Our goal for 2030 is to ensure rewilding becomes mainstream in science, policy and practice, and is recognised globally as being credible, practical, and inspiring: a key approach for people, nature, and climate.
The Global Rewilding Alliance recognises and works actively to strengthen the importance of Indigenous communities as stewards of their traditional homelands, and as key partners to protect, restore, and rewild our Earth.
If you as an organisation are interested in joining the GRA, please contact Alister Scott,

The Human Face Of Rewilding

Rewilding goes with the grain of local communities and economies; social participation and entrepreneurship cut across all our work. The human dimension of rewilding has been described in the Global Charter for Rewilding the Earth: Advancing Nature-based Solutions to the Extinction and Climate Crises. The human dimension is further elaborated on in the 12 ‘principles of rewilding’ of the Charter.

Since local communities play a critical role as guardians of global diversity, they are actively involved in many rewilding activities undertaken by the GRA membership on all continents, such as the restoration of the prairies in USA, rewilding and restoration of forests and rivers in northern Sweden, and work with Aboriginal communities across Australia. In the unique Enonkishu Conservancy in Kenya, the Maasai community has set aside part of their land for rewilding in parallel to introducing sustainable rangeland management and implementing a tourism model where all guests are a part of the rewilding journey.

Rewilding directly supports human wellbeing through ecosystem services, connecting humans to nature, and creating new, local, and sustainable economies. Rewilding thus directly creates the foundation of many of the UN’s 17 Sustainable Development Goals (SDGs), especially #13 (climate change), #14 (life below water) and #15 (life on land), but also #3 (good health) and #6 (clean water and sanitation). Income from ecological services has the potential to reduce poverty (#1), inequality (#10) and raise living standards of local communities (#8). Peace Parks Foundation’s holistic, community driven ‘Herding 4 Health’ initiative and a family-planning project are promising efforts addressing the three last SDGs plus SDG #3 and #6 in the context of rewilding. Peace Park’s ‘Rewilding Southern Africa’ also addresses the root causes of the COVID-19 pandemic by reducing social inequalities and ecosystem degradation, and transforming the way we relate to the environment in which we live – as expressed by the WHO COVID-19 Manifesto. A Disease Surveillance Project of the Wildlife Conservation Trust in India is also set up to avert future epidemics.

The restored wildebeest population on the Serengeti means there are almost no wildfire outbreaks at all, while the rejuvenated grasslands now capture carbon. Photo: Public domain/Daniel Rosengren.
Restoring Wildebeest Populations in Serengeti, Tanzania
Involving the movement of over one million animals, the annual wildebeest migration across East Africa’s vast Serengeti grassland is one of the world’s most awe-inspiring natural spectacles. It’s hard to imagine such a herbivorous horde disappearing from the landscape. But this nearly happened in the first half of the 20th Century, when poaching and disease (the rinderpest virus) saw wildebeest numbers plummet to around 300,000.
The consequences of this collapse were profound. Much of the 25,000 sq. km. Serengeti ecosystem was left ungrazed. The dead and dried grass that accumulated as a result became fuel for massive wildfires, which annually ravaged up to 80 per cent of the area, making Kenya and Tanzania a significant regional source of CO2 emissions. Over many years, this state also led to the loss of organic carbon from soil carbon stocks, as the entire Serengeti ecosystem became a net carbon source.
The situation changed in the late 1950s when a rinderpest vaccine eventually became available, leading to the effective eradication of the disease. This, combined with anti-poaching measures, saw the wildebeest population gradually recover to natural levels. More animals meant more grazing, which saw carbon shifted from above-ground combustible biomass to the soil via dung, thereby promoting carbon storage and reducing the incidence of wildfire. Every time the wildebeest population increased by 100,000 animals, the area being burned reduced by around 10 per cent. More trees grew, storing more carbon.
Today, the impact of the restored wildebeest population on the Serengeti landscape means there are almost no wildfire outbreaks at all, while the rejuvenated grasslands now capture carbon up to the equivalent of the annual anthropogenic CO2 emissions of Kenya and Tanzania combined. The Serengeti has become a carbon sink once again.
The case of the wildebeest in the Serengeti is just one example of how animals, and their presence or absence in a particular ecosystem, can impact the capacity of that ecosystem to store carbon. It also shows how the loss of just a single species can have far-reaching implications for ecosystems and climate. By being an integral part of a larger food chain – as wildebeest are – the presence or absence of such species may trigger knock-on effects that grow through the chain to drive significant amounts of carbon into long-term storage on land or in the ocean, or release it into the atmosphere.
Source: Animating the Carbon Cycle: Supercharging Ecosystem Carbon Sinks to Meet the 1.5°C Climate Target, by Daniel Allen, GRA Publication Series 2022/01.

Rewilding In Action

Rewilding is the most powerful action we can take to protect human society and communities around the world. By helping nature to heal itself it can:

* Tackle the climate emergency. We must stay below a 1.5°C rise in average global temperature. Rewilding provides the most powerful, long-term, nature-based climate solution that removes surplus carbon generated by humans from the atmosphere. It rebuilds natural resilience against floods, droughts, wildfires, and other threats.

* Repair broken ecological systems and, by doing so, promote survival of species and reduce the threat of the sixth mass extinction.

* Reduce the risks of zoonotic pandemics.

While rewilding may appear to be the luxury of developed countries who can afford it, in reality it is about undoing the mistakes of our past. Rewilding is about rebuilding our connections – rural and urban – with nature and understanding that when our natural ecosystems are healthy, our soil, water, climate, economies and we are healthier too.

The different overviews on the following pages from Australia, Europe, South America, Sri Lanka and Africa and preceding pages from India provide some detailed examples of ‘rewilding’ in action.

Animal ecologist (Ph.D.) by training, Magnus was formerly Head of the Conservation Unit at WWF Sweden and Head of the Europe/Middle East Programme at WWF International. As Co-Director of GRA, he is engaged in the integration of nature, climate and sustainable food production. Karl is a scientist by training and an environmental campaigner. Formerly, he worked for many years both at WWF International on global and EU campaigns and for the Club of Rome. For the last 10 years he has contributed frequently to the global campaigns conducted at the WILD Foundation and is Co-Director, GRA.

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