Tigers of The Tide, Breathing Roots et al. The Sundarbans with Dr Radhika Bhargava.

Heart of Conservation Podcast Ep#31 Show Notes (Edited)


Hi, I am Lalitha Krishnan and you’re listening to Ep# 31 of Heart of Conservation. I bring you stories from the wild that keep us all connected to our natural world. You can listen to Heart of Conservation on several platforms and also read the transcript right here on my blog Earthy Matters.

Today’s episode is about the Sundarbans. I recently made a trip there and I have to tell I am so spell bound by the immensity and biodiversity of the world’s largest delta which we share with Bangladesh. To be honest, I didn’t know about these 2 facts earlier.  Almost everything I saw was unique somehow, something I had never seen before. I knew I had to find an expert to learn more about the Sundarbans ecosystem. As luck would have it, I came across a social media account @onesundarban which belongs to Dr Radhika Bhargava, my guest here on episode # 31.

In her own words, Dr Radhika wears multiple hats as a coastal geographer, geospatial analyst, and a National Geographic Explorer. She is a Research Fellow at the NUS Centre for Nature-based Climate Solutions working with wetland conservation in Asia. She recently completed her PhD at the National University of Singapore. We will discuss her research some more but for now, Radhika, welcome and congratulations on your PhD. I feel so privileged to have you share your knowledge and experiences with us.

Radhika Bhargava: Hi Lalitha, thank you so much for having me on your podcast. I am so excited and I am so happy that you recently visited the Sundarbans. I am really looking forward to your questions and interacting with you on Sundarbans. 

Lalitha Krishnan: Lovely. So, let us start. Radhika, what made you, first, focus on the mangroves for your research and why must we be watching the mangroves to check on the health of our planet? 

Radhika Bhargava: I started working on mangroves during my Masters actually. I was part of a project where they were looking for someone to do coding or use coding /computer languages to identify mangroves of South East Asia. So, you use satellite images and you have to interpret where the mangroves are. There were many other forest classes that I was interested in studying but somebody had taken up those classes or somebody had taken up those forest areas to study using satellite imagery. They were only left with mangroves and then, I joined the lab. Nobody was willing to take up this project because there was a lot of computer coding required. And, coming from ecology, biology or management backgrounds, we were not trained in it. I saw this gap and even I didn’t know any computer programming at that time. But then, looking at this desperate need that nobody is doing, I said, “Sure, why not? I will give it a try.” I started learning coding from scratch and then my focus was mangroves. So, that is how I learnt a lot about mangroves. I became so curious that through the two years of my Masters which was at University of San Francisco, the focus was Environmental Management. I ended up with all my class projects or side projects related to mangroves. That’s how I came across the Sundarbans.


You asked me, “why must we be watching the mangroves to check on the health of our planet?” There are many reasons. Especially that mangroves are coastal protectors. They protect the sea from storms and cyclones. Their roots help in purifying water but specially they store or remove carbon dioxide which causes global warming. They store it within themselves and keep it there for millions and millions of years. They have such characteristics that can tell about the health of the planet and actually help in improving the health.


Lalitha Krishnan:  That’s quite amazing. I love the part about you learning coding from scratch. Look where it has taken you.  Radhika, I’m curious about your social media handle. Why its called ‘One Sundarban? There must be something to it. There must be a good reason why you have called it so?


Radhika Bhargava: So glad you asked me this question because initially, people thought that maybe I did not get the handle “Sundarbans’ and that it why I went with ‘One Sundarbans’. Also, I think, I have had that account for maybe two years. I only joined social media because I felt the urge to share about the Sundarbans. When I realised that a storm can come, a cyclone can come in that area and nobody would even know that somethings happening…  So, I felt that I am at a place that I can share so I should take that initiative. So, I only joined social media to share about Sundarbans.

And why ‘One Sundarban’?

Sundarbans is across India and Bangladesh. It is one ecosystem. As a researcher, it really annoyed me initially when I would come across studies or management plans or government records that focused on just one side-either India or Bangladesh. So, for me, ‘One Sundarban’ is one ecosystem so hence ‘One Sundarban’ but after I pondered about it a bit more, about the terminology, I realised that “sundar” is in Hindi, In Bangla and in many local Indian languages, “sundar” is beautiful and “ban” or “van” is forest. So, it is just one beautiful forest. If I branch out of onesundarban, this name still holds.

-Radhika Bhargava


Lalitha Krishnan: Right. That is a beautiful thought and it makes so much sense because you cannot save it in part. It is half the story then. Radhika, how much ground did you cover during your research and what techniques did you employ to cover this vast area?


Radhika Bhargava: Right. So, I worked across India and Bangladesh. So, Sundarbans, for those who are not familiar, is 10,000 sq. kilometres of just mangrove forests. It is made up of many small islands-I do not even know the exact count-but, adding both India and Bangladesh, it is going to be more than 200 islands. My initial idea was to capture the ecosystem. Since I use geo-spatial analysis, which means using satellite maps and satellite data to understand what is happening on the ground, I was able to understand that from one aspect, right? Since satellite images can help you cover that vast area but when I went into the field, I still intended to go from the easternmost to the westernmost and northernmost to the southernmost island. For that, I first recorded shorelines from on top of a boat. I installed a Go Pro camera on a boat and then we would go parallel across shorelines and then I would be doing a commentary on those videos. Later on, I converted those videos into multiple images, and so from the observations in those images and my commentary, I collected some data.


So, we covered around 240 kilometres just of observation. The travelling kilometres were much more. And then, I went to around 16 villages to conduct interviews with the communities to understand their part of the story of the work I was doing.


Lalitha Krishnan: That is very extensive. You must have learnt a lot. That is quite amazing Radhika.


Radhika Bhargava: Thank you so much. If not for COVID, I had another few methods I wanted to try out too which would have made me go into the forest to collect some  forest bio-physical  measurements  within the forests but because of COVID, I had a shorter amount of time and PhD scholarship and all restricted me. So, there was still more that I wanted to do.


Lalitha Krishnan: But you must have amassed quite a lot of information.


Radhika Bhargava: It took a long time to process it. I think I would still go back to that data set although I have written my thesis on it, there is still so much more to get from it. I hope I get a chance to do that in the future.


Lalitha Krishnan: I am sure (you will). These things never go to waste – what you’ve observed, what you’ve learnt and what you have surveyed. You know, even though I have lived by the sea, I never bothered to familiarize myself with mangroves. It was in the Sundarbans, that too on a boat that I witnessed up close, the diversity of mangroves species.  They are quite different from each other apart from the fact that they seem to be thriving in this cocktail of river and sea. Could you talk about some of these mangroves species and how unique they are? The snake roots, breathing roots for e.g. or the way some species propagate themselves with seed balls that float till they find a suitable location? It is all so fascinating.

10: 34

Radhika Bhargava: In just a few lines you actually explained how one comes across and becomes fixated with mangroves. Initially you lived by the sea, I come from a land-locked place. So, I had not even heard the word ‘mangroves’. So even today when I tell people I am doing research on mangroves, they assume I am researching mangoes. The word is so unfamiliar.

Lalitha Krishnan: There’s somebody worse than me that means.


Radhika Bhargava: I was worse than you. Despite visiting coastal areas with my parents, I never processed why there are trees on the beach or why there are trees on the water. Especially in Bombay. Goa, Gujarat side of India. So, I also learnt about it through books and through reading research papers until I went to the Caribbeans to do some project on coral reefs. So, we had a small project where we were snorkelling and looking at fish nurseries around mangrove roots. So, I thought that was cool. But I did not realise that there’s this amazing ecosystem like Sundarbans  or Bhitarkanika in Odisha, where in sediment-rich mangroves you can’t even see what’s happening under water. So, I also came to mangroves in a similar way; I said “what are these crazy roots?” A lot of people whom I have talked to say mangroves for them are like some sci-fi movie, when they come to the Sundarbans.


It is mainly because of the roots like you said. Mangroves have this crazy kind of roots, especially to adapt to the extreme environment they grow in. By extreme environment, I mean they grow at the interface of land and water. So, they are often flooded with salt water although they receive some fresh water from rivers as well. They get flooded twice a day during high tide. They are exposed to extreme waves. When I am explaining this, I like people to imagine that these mangroves are humans. Or to become mangroves themselves. So, if you’re standing at such a place or if you are to stay there for so long, you would develop some kind of adaptation that would help you first, stand there steadily. That the hold of the roots… the snake roots or the prop roots as it is called. that helps them stay aground. There are four to five kinds of mangroves roots. Basically, the first role they play is help them stay in that silty, flooded land. The second thing specially in the Sundarbans or Bhitarkanika, where there is a lot of sediment that these mangroves are standing on, the second thing they need to do is to be able to breathe. But the soil and the water mix are so poor in oxygen content that they have to grow their roots up or their roots have to come from their branches and then go into the ground, unlike other plants which grow roots hidden in the ground. So the roots that are propping up from the ground-there’s a type of root called pencil roots- which look like if you’ve stuck pencils in the soil, they look like that. Or buttress roots… All of these roots apart from giving them stability, they also help them get oxygen from the air. So, many plants get oxygen from the atmosphere directly and through their leaves and through their stems but mangrove roots also get oxygen content from the air to support breathing for the plants. So, these are some adaptations that mangroves must bring in to stand tall in that extreme environment.

Source: Nature Picture Library

You also asked about propogation of species. How mangroves grow mangrove babies, right? So, if you are a mangrove and you’ve figured out how you are going to stand and how to breathe in this fragile, dynamic ecosystem then the next thing is to figure out how are we going to reproduce? Unlike many trees which produce seeds–those seeds get propagated by wind or by animals or by water–some of the mangrove trees do produce fruits. And then within these fruits, there are seeds which finally find a ground and grow. But, it’s also common in certain kinds of mangrove species to not produce seeds but produce a mangrove propagule. That propagule is just a mangrove baby that’s growing on top of its mom. You might have come across these green sticks hanging from the tree, they are mangrove propagules. They hang from the tree and until they are ready to go- the weather conditions, the time of year, the tidal conditions etc are good-the mom drops them in the water. Now they are floating in the water but these are not seeds ready to be germinated. These are germinated plants which function like any other plant and it keeps floating until it finds the right elevation, the right tidal conditions, the right slope, and the right area to settle in. So, that stick or propagule has that much sense to find the right place for its survival.  It floats horizontally. Once it finds the right place, it becomes vertical, the centre of mass changes and it automatically goes into the soil. Which is just mind-blowing for me. In a way, they are like mammals. In mammals…humans, babies grown within the mum until they are ready to come out. I find equal similarities.


Lalitha Krishnan: It sounds like they have an intelligence of their own. There is so much we do not know.

17: 25

Radhika Bhargava: There are things people who study these processes are still finding out. Things we know have been published but there is so much more, so much unknown when it comes to mangroves.


Lalitha Krishnan: Thank you so much for explaining that. Talking of species, the animals that exist in the Sundarbans also seem to have adapted to this unique environment. We saw the rare Mangrove pitta, the Fishing cat we didn’t see but I know it’s there and the swimming Bengal tiger, which is the only tiger that lives in a mangrove system. How cool is that? What makes them so different or what can you tell us about them?


Radhika Bhargava: If we are talking about Sundarbans, how can not (talk) about the tiger? The Royal Bengal tiger is found in many places in India or in the South Asian subcontinent. However, the subspecies of the Royal Bengal tiger—I’m not sure if sub-species is the correct word—but the evolution of the Royal Bengal tiger that found in the Sundarbans is quite different from the other Royal Bengal tigers that are found, in say, Central India, where I come from.


The main difference in their adaptation to living in the Sundarban Delta. In those mangroves, in that flooded ecosystem. Just like I was explaining earlier how mangroves adapted to this soil, sediment, flooding conditions, the tigers of the Sundarbans also have to.


If you are a tiger, you would need sweet water or fresh water, as they say, to survive. But the tigers of the Sundarbans are living in a delta filled with salt water. Their houses or their land or their habitat, gets flooded twice a day which tigers of Central India do not experience.

They go to a fresh water pond within their forest to get water but then they can go back to their caves to chill. But there are no such structures that are dry all year around for the tigers of the Sundarbans. And if they want to go from one place to another, there are huge rivers and streams in between which they have to traverse. So, tigers and other kinds of cats can swim naturally but the tigers of the Sundarbans use swimming as their means of transportation. When their islands get completely flooded because of high tide they climb on to a tree and stay on the tree twice a day during high tide conditions. Hunting also, for  for these animals is very different. Now you don’t have a grassland to run and catch deer but you have to very strategically traverse the silty, quick-sand type or quick-mud type of terrain where you cannot run a lot because of the roots–that I just explained about earlier—would stop you from running far distances.


So, it so amazing how the Royal Bengal tigers of the Sundarbans have adapted to live in these conditions. However, these extreme conditions- lack of habitat these days, lack of availability of sweet-water ponds and extreme environmental and anthropogenic pressures are affecting these tigers in a way that now, they are more exposed to the local villages. A lot of human and tiger negative interactions have started to take place. There are a lot of theories of why some of these tigers are also maneaters. These theories that make sense to me are related to the extreme environment and increasing environmental and anthropogenic pressures that are making them encounter humans in a negative aspect.


Lalitha Krishnan: Right. I imagine tigers or for that matter any other animal there having to climb a tree twice a day to escape drowning if they cannot swim. I never would have even thought that far.  Thank you for explaining that.  It is quite a hard life even for a tiger. I was thinking of the deer…


Radhika Bhargava: Did you see any tiger?


Lalitha Krishnan: No, we did not see any tiger and we did not expect toeither. They told us not to expect to see a tiger. But we did see paw prints. What is fascinating is that—I have seen scratch marks of tigers on trees but here, we actually saw scratch marks on the mud. We had such an excellent forest guide. Mud looks like mud; it was all wet but he manged to point that out to us. It was quite distinct. That was fascinating.


Coming back to the Sundarbans and the ravages of nature, Cyclone Bulbul in 2019, Cyclone Amphan in 2020, Cyclone Yaas and Jawad in 2021 have all struck and affected these low-lying islands.  What makes them so defenceless? What were the losses incurred with every cyclone-hit?


Radhika Bhargava: The “defenceless” word here is something I should talk about. It’s Yes and No. Mangroves are known to protect inland areas from the impacts of storms and cyclones. So, in a way they are not defenceless. They have those defences. And, even the all the cyclones that you named just now; Kolkata was the least impacted if we are speaking from India’s perspective or Khulna or Dacca if we are speaking from Bangladesh’s perspective. They were impacted but the impact was so small compared to what it could have been if the Sundarbans was not there. So, Sundarbans is still holding ground, defending inland areas.

However, because of ongoing anthropogenic pressures; to name a few: the shipping channel that has been formed within the Sundarbans which is a protected area. It should not be converted into a water highway.

Or a coal plant coming into Sundarbans or other aspects, the extreme erosion of land; the loss of land which was the focus of my research, causing mangroves to degrade and get lost is causing them to reduce the amount of defence they could have provided.


When you are talking of defence I would also talk about the people. The people of the Sundarbans, I feel are resilient especially in terms of how they manage when these reoccurring cyclones, with the frequency of three to four times a year, impact them. However, with reduced options of livelihood, with reduced preparedness because they are managing a lot of land, and cyclones, lack of livelihoods, lack of protection altogether, their resiliency is also getting reduced.

So, although the people are not defenceless to start with, the conditions are making them such. So, if you hear, I just made a parallel between the resiliency of the mangroves and the resiliency of the people; yet both their resiliencies are getting reduced or impacted. Which on a side note is the conclusion of PhD thesis.


Lalitha Krishnan: Good. So, during my visit to the Sundarbans, I noticed that the embankment to my resort was half washed away. I was told it was the cyclone which is a recurring factor there. Is there more to it?


Radhika Bhargava: Great observation Lalitha. I am so glad that you didn’t buy into just the story that a cyclone comes and destroys the structure. So, to give a bit more context to our audience, the soil in the Sundarbans , the sub-sediment in the Sundarbans is silty;  it’s clayish. So, if you want to understand this, clay that a potter uses to mold clay into, it is that kind of clay, on which if you put a step, just as a 55kg human, the soil is going to get compressed and you’re going to slip away.

Imagine putting concrete slab on this silty and soft soil? It’s like creating a hard line in a very dynamic system. That concrete is going to eventually collapse. I’ll explain very quickly how. So, there’s a concrete slab but underneath, is a soft silty soil. And underneath, there are waves that are coming in and out throughout the day, So the waves are going to take some of that soil with them. Or that soil which may be a bit harder during low tide is going to get mixed with water and become soft. So, the concrete slab on top is eventually and slowly and slowly going to collapse. And, then, it’s going to be like the embankment that you saw during your visit.

So, when a cyclone comes, all of this just gets exaggerated. But these processes are happening on a daily basis, causing these embankments to fall and collapse. Yet, when these embankments fall, another embankment of such poor design is built maybe 200 mts. away from the current shoreline. This keeps on repeating to the point where the place you stayed, you saw the 5th embankment collapse in the past 40 years or so. This is something I also worked on during my PhD to understand why this poorly designed embankments are still around and how are they impacting the local people. So, what I explained earlier about the reduced preparedness or resiliency of the people, that lack of preparedness, that lack of having other options make them rely on these quick yet poor solutions. So, the demand also increases for these. One thing collapses, yet the second time, they want the same thing to be built so that they can get some short-term benefits of prevention of flood or some people start living in tents- who have also lost houses because of all of this, start living around the embankment. So, it becomes like a vicious cycle of land loss, poorly designed embankments come in, poorly designed embankments cause more land loss yet more of these embankments come in and the cycle continues.


Lalitha Krishnan: Again, I never thought of it. I am learning so much from you Radhika.  Finally, my last question for you. Could you share a word that was perhaps part of your research or significant to you in some way? Something new for all of us.


Radhika Bhargava: So, the word I want to use, building off of what I just explained about embankments, is a word called ‘maladaptation’. It is very relevant because in the last IPCC report, it was used to highlight a pressing issue in our fight against climate change. I will explain it in pieces. Adaptation means any form of project, idea or implementation that comes in to reduce impact or anything. But in climate change context, climate change adaptation is an adaptation such as building a sea wall, or other things that help you reduce the impact of climate change. So one impact could be flooding, sea-levels rising and so on. Maladaptation to climate change means when that adaptation which is built to reduce the impact of climate change fails but not only does it fail but it causes other negative impacts to the local community or the global community.


So, when an adaptation fails and causes more negative impact it turns into a maladaptation. This is a word that I realise through the work I have done in the Sundarbans, or through my research in the Sundarbans, and I am hoping that I can contribute more to the growing literature of maladaptation.


Lalitha Krishnan: You have increased our vocabulary. Thank you so much Radhika, we have covered a lot and learnt a lot from you. It’s been a real pleasure talking to you.

Radhika Bhargava: Thank you so much Lalitha. I love talking about the Sundarbans and sharing about it from a place where I did not know and then I had the privilege to go and learn about it. So, I feel that it’s my responsibility in a way to share about it in any medium and form I can. So, thank you so much for giving me this platform to talk more about Sundarbans and the issues people and the forests are facing over there.


Lalitha Krishnan: Thank you Radhika, I feel the same way. I feel there’s so much we don’t know and I want to share. I am luck I found you.


Radhika Bhargava: One quick thing to add for our listeners. So, you learnt a lot about Sundarbans, and mangroves. So, one takeaway you can do for me and Lalitha would be if you can go and tell more people in your social circles about how cool and awesome mangroves are and how amazing Sundarbans is. Thank you.

Lalitha Krishnan: I hope you enjoyed listening to episode #31 and Dr Radhika as much as I did. If you know somebody who is doing incredible work and his/her story needs to be shared do write to me at earthymatters013@gmail.com Watch out for my next episode. Till then, take care. Bye.

Birdsong by hillside resident, the collared owlet.

Cover photo: courtesy Dr Radhika Bhargava. Podcast cover artwork by Lalitha Krishnan

Disclaimer: Views, thoughts, and opinions expressed in the podcast and show notes belong solely to the guest featured in the episode, and not necessarily to the host of this podcast/blog or the guest’s employer, organization, committee or other group or individual.

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