Plum-headed Parakeet eating fruit, Delhi, India

A Guide to Ecological Restoration

Each region is unique with its unique ecosystem and requires unique ways of restoration. Sohail Madan, Centre Manager-Delhi, Bombay Natural History Society, helps us understand the biodiversity and ecosystem of the Aravalli Range around Delhi-Faridabad-Gurugram

Photographs: Bombay Natural History Society, Delhi

To understand a natural ecosystem, we need to understand that humans live in a complex and connected web with flora and fauna. If the air or water bodies in our region are highly polluted and there is a lack of biodiversity, then the survival of any life form is threatened. So, ecological balance means rich flora and fauna, and good quality of surroundings for human habitats.

The Aravallis
Landscape of Asola Bhatti Wildlife Sanctuary, Delhi, India
Landscape of Asola Bhatti Wildlife Sanctuary, Delhi, India

The Aravalli Range is considered to be the oldest fold mountain system in the world. It dates to the Proterozoic Era (2500 to 541 million years ago). This 560-km long range starts near Delhi, passes through southern Haryana and Rajasthan, and ends in Gujarat. The highest peak, Guru Shikhar at 1,722 metres (5,650 ft), is in Mount Abu, Rajasthan.

Aravalli Hill Gecko
Aravalli Hill Gecko

It has a unique biodiversity as it a semi-arid region and certain species are only found here. For instance the Aravalli Hill Gecko is only present in this region and nowhere else in the world. The common leopard also lives here. The region has been inhabited for over 4,000 years.  

If you see the Delhi-Faridabad-Gurugram area, it’s a huge metropolitan complex. And in the last 20 years, we have seen the destruction of natural habitats and ecosystems, largely due to development issues and migration to the cities leading to bursting infrastructure. The natural streams, forest areas, grasslands, have all been disappearing. So there is an urgent need to carry out ecological restoration as the degradation is faster than the natural recovery.

In fact, some studies indicate the 40% of the country needs ecological restoration. Grasslands, mangroves, forests, rivers, lakes have degraded rapidly in the last few decades.

What is biodiversity?

A biodiverse ecosystem includes a variety of native plant species, trees, grasses and shrubs, animals, birds, insects, even invisible microbes and humans. Together, they perform all the ecosystem services such as prevention of soil erosion, climate change mitigation and more. Biodiverse ecosystems are superior to monoculture ecosystems. This means that just one variety of eucalyptus or keekar will never make a forest and give the same services as a biodiverse ecosystem.  

Why is the ecosystem important for us?

A healthy, natural ecosystem includes protection of biodiversity and enhancement of ecosystem services. From a forest we can get ecosystem services like carbon sequestration, oxygen, disaster prevention, water security, climate change mitigation, raw material, so different aspects of biodiversity and ecosystem services combine to make a healthy habitat.

Covid-19 has also made us aware that a tree does not provide us with clean air only. Trees are also helpful in mitigating stress and leading a happy life. There’s a lot of research now pointing towards this direction. Just by looking at the tree, I help my mental self as well.

What is Ecological Restoration?

Ecological Restoration is a process of assisting the recovery of an ecosystem that has been degraded, damaged or destroyed. Does planting trees reverse the damage? No, this is only one activity in the restoration cycle.

Ecological restoration is a holistic process–it looks at both abiotic and biotic elements of a forest. Abiotic elements include the soil and hydrology of the forest. This is the bedrock on which a forest is built. We need to study the type of soil, the amount of rainfall it gets, the water holding capacity of the soil, water holes, moisture content.

The biotic elements are the plants and animals.  

Fungus Garden on termite mound, Aravallis, Delhi
Fungus garden on termite mound, Aravallis, Delhi
Why do we need to intervene? Doesn’t the forest recover by itself?

This is not a correct perception. In some cases, the forest might recover on its own. But in most cases, this won’t happen because we are damaging the system faster than it can naturally recover. So it needs intervention, but ecologically sound intervention and only assistive regeneration. Ecological restoration will lead to a healthy natural ecosystem.

How is ecological restoration different from other approaches such as afforestation, plantation and reforestation? Which regions need ecological restoration?

Afforestation and reforestation focus on planting trees. The focus is not on the entire ecosystem and biodiversity. They also do not focus on species integrity. However, in ecological restoration, species integrity and ecosystem integrity play an important role.

Ecological Restoration is a fairly new discipline, not more than 40 years old and well established in North America and Western Australia. It has multiple branches and specializations. We can do ecological restoration of all ecosystems—rivers, lakes, deserts, grasslands. We have to study that region and then assist in regeneration. Ecological Restoration is practiced widely across the globe. It is done in wilderness areas, urban areas and even industrial sites.

Ecological Restoration is given great importance in this century, as human activity has altered 75% of the Earth’s geography with devastating consequences. World leaders are now taking stringent actions to reverse global climate change and degradation. To name some important treaties and steps that lay down the guiding rules and regulations:

  1. On World Environment Day, June 5, 2021, United Nations declared 2021-2030 a Decade on Ecosystem Restoration.
  2. The Convention on Biological Diversity aims to conserve biological diversity, promote sustainable use of its components, and to support the fair and equitable sharing of benefits arising from the use of genetic resources. This convention opened on June 5, 1992, at the Rio Earth Summit, a conference organized by the United Nations on Environment and Development. It remained open for signature until 4 June 1993, and received 168 signatures. It officially came into force on December 29, 1993.
  3. The Bonn Challenge is a global challenge with a goal to bring 150 million hectares of degraded and deforested landscapes into restoration by 2020, and another 350 million hectares by 2030. This was launched in 2011 by the Government of Germany and IUCN (International Union for Conservation of Nature).
What caused the degradation of the Aravallis?

There have been many factors for this. To begin with, the Prosopis juliflora or vilayati keekar/baavlia that we see in this region is not a native tree. It was brought by the British from Mexico and South America when they moved the capital from Calcutta to Delhi. The keekar did thrive but it created a threat to the native species. And over time, the natural ecosystem began to degrade with invasion.  

Foreign species take the space of the native species. And when the spcies integrity is not mainitained, the relationship with the ecosystem begins to break. Eventually, all the biodiversity also begins to disappear and degradation sets in.

Which are the native species of the Aravallis?
Amaltash, native to Aravallis, Delhi
Amaltash, native to Aravallis, Delhi

This area has mostly deciduous trees. To name some trees: Palash (Butea monosperma), Amaltas (Cassia fistula), Desi Keekar (Vachellia nilotic), Ronjh or Safed Keekar (Acacia leucophloea), Peelu (Salvadora persica), Dhau (Anogeissus latifolia), Bistendu (Diospyros montana), Chamrod (Ehretia laevis), Indian Bael (Aegle marmelos), Heens (Capparis sepiaria).

Grasses such as Kash, Vertiver are also important. Shrubs found here are: Gangeti (Grewia tenax), Kareel (Capparis deciduas), Adusa (Justicia adhatoda) and Vajradanti (Barleria acanthoides).

Most of these plants/trees have medicinal uses, attract birds and butterflies. They also need less water and can grow in hardy conditions.

What is the Ecological Restoration process?

Ecological restoration follows a natural progression. We start working with the soil and hydrology of the area. This in turn helps the soil microbes and microscopic life living in the soil. This turns the soil into good soil, and eventually grass shrubs and pioneerspecies can establish themselves. Then there is a steady movement towards succession of different plants and fauna.

What are the important factors for ecological restoration of any site?
Rose-ringed Parakeet eating Bistendu fruits, Delhi, India
Rose-ringed Parakeet eating Bistendu fruits, Delhi, India

This is a scientific and rigorous process based on ecosystem integrity and species integrity. We try and keep them intact or try and improve them. When we start work on a site, we compare it to our reference site. Here in the Aravallis, we would refer to the Mangar Bani Sacred Forest, which has been left pristine for over hundreds of years. All thanks to a saint who visited this place hundreds of years back and asked the locals not to interfere with the forest. This belief has kept the ecosystem intact.

Can all ecosystems be restored in the same manner?

Our focus is biodiversity and optimal intervention. Optimal intervention means we don’t apply the same methodology to every ecosystem. We study the level of degradation that the ecosystem is suffering from, and fine tune our intervention to make it optimal. Doing too much work in a forest is counterproductive. Sometimes it results in more loss of biodiversity than any good.

The ecological resilience of a habitat is the natural ability of the ecosystem to recover on its own. So if the ecological resilience is high, there will be lots of spontaneous regeneration in the forest. And we would need very low intervention.

But if the ecosystem is highly damaged or degraded to a very bad level, then the ecological resilience, the ability of the ecosystem to recover on its own is lost. At that time, there would be low resilience, which will need active restoration, lots of work. We need to find out the resilience of the habitat to lead us to what we want to do.

The most important thing when we start ecological restoration project is to understand what we want to achieve and why we are doing what we are doing. It is not just planting trees because it’s become a craze and it will become a good social media photo opportunity, but to actually help us secure futures for our future generations.

What are the signs of a healthy, restored ecosystem?

When we restore our ecosystem, the attributes that we can see are a stable abiotic and biotic environment. If we plant trees there, then some tree dwelling birds will return to the area. If we make a pond, then some birds which need water would return to the area. If we make a big lake, then other aquatic bird species will come back. So slowly, the return of these bird species or the presence or occupancy of these bird species tells us about the resilience of the forest. And this can be replicated for butterflies, mammals, fishes. So, this return is an effective way to study the progression of ecological restoration work.

We see that the natural cycles are functioning well–air cycle, carbon cycle, nitrogen cycle. There is improved resilience and self organization of the ecosystem. We have desired species diversity and abundance. At this stage, it means that we can return the ecosystem to a place where original eminent inhabitants of the forest can come back and in good numbers. Absence of non desirable species is also very important attribute of a restored ecosystem.

The threats which cause the degradation of the forest also need to be removed or worked on, so that the forest doesn’t degrade further or after it has been restored. These could be urbanization, policy threats, or people cutting trees for firewood.  

Swarm of butterflies, Delhi, India
Swarm of butterflies, Delhi, India
How much time does it take for a region to get restored?

Ecological restoration is a long term project with some signs like regeneration during monsoons becoming intensified or increased water retention and decreased water run off being apparent quite soon. For the system to recover fully and go back to having all ecological or biological cycles restored in takes 10, sometimes 20 years. With assistive regeneration we could provide a framework and set the forest on a path of faster recovery. Time frames are dependent on level of degradation of the site and requirements of interventions to stabilize the ecosystem.

This column has been reproduced from a webinar organized by the Manav Rachna Centre for Peace and Sustainability in collaboration with the Bombay Natural History Society.

About Sohail Madan
Sohail Madan, Centre Manager-Delhi, Bombay Natural History Society

This engineer-turned-environmentalist has been instrumental in development of the largest butterfly park in North India inside Asola Bhatti Wildlife Sanctuary. He has also played a crucial role in advising the Department of Forests and Wildlife, Government of NCT of Delhi on implementing restoration projects and biodiversity surveys. He also spearheaded the conceptualization of citizen science monitoring programmes including Big Butterfly Month, Delhi Dragonfly Festival, Delhi Moth Week, various bird counts and winter raptor surveys.

He developed the Green Skill Development programme on behalf of the Ministry of Environment, Forests and Climate Change, Government of India. He has implemented the training for frontline forest staff of the Dept. of Forest, Govt of Madhya Pradesh, while he also oversees the regional education centres at Bharatpur (Rajasthan) and Indore  (Madhya Pradesh). He was awarded with Dr. B Kiowta Lifetime Achievement Award in 2019 for his work on dragonfly conservation and youth development by Indian Dragonfly Society.

E-mail:, Mob: +919717838299


13 thoughts on “A Guide to Ecological Restoration

  1. Very good post about ecological restoration process. Highly informative and nicely written. Keep up the good work.


  2. Read this before already but thought to share something on it as it was filled with rich research work. I never knew about Big butterfly or dragon fly or even Moth festival, this is news to me. While researching for my film i have extensively read and worked around Asola and the Aravalis and this came as a welcome post. Thank you.

    Nara x

    Liked by 1 person

  3. Ecological restoration is indeed the need of the hour. Our beautiful planet is being degraded at an alarmingly fast pace and needs to be healed and nurtured. This is a very insightful article that brings so much information to the table.


  4. That was a detailed and informative post on ecological restoration. Starting from various global conventions to details about native species and ways and processes of ecological restoration, you have covered a great deal of topics under one post. Thanks for enlightening us on this.

    Liked by 1 person

  5. Such a beautiful article and so very important at the moment. It is important to take care of our planet and it is so nice to learn about ecological restoration process. Thanks for this post, I really learned something new today.

    Liked by 1 person

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