CHENNAI: When the concept of biodiversity is relegated to the pages of long-forgotten Biology textbooks and to the sole custody of ‘experts’, we fail to see the wealth of it all right in front of us. For how many of you, at the mention of the word biodiversity, thought of Amazon forests and coral reefs and not Marina or the Pulicat lake? To turn your attention homeward, a group of naturalists in Chennai has taken up the mammoth task of documenting the coastal biodiversity of Chennai and its neighbouring district. This, soon, evolved into a project to map the entire coast of Tamil Nadu. The end of the first phase has resulted in a catalogue of over 300 species of fauna and flora found along the coast from Pulicat to Puducherry. And there’s much more to come, assures Yuvan Aves, naturalist and core member of the team behind this undertaking.
The project has several starting points, he begins. “One is the Save Pulicat campaign. It required us to educate and evoke coastal ecology in public awareness; so that they will have a greater feeling for the cause and stand up for it. I’ve been involved in it for the past three years. Later, the government proposed a road over the Adyar estuary. We had to create some public awareness around it. That led to walking on the shore and understanding (from various resources) what shells are there and everything. After that, we decided that we’ll document the entire coast of Tamil Nadu — its biodiversity, people and threats,” explains Yuvan, who is also a member of the Madras Naturalists Society.
The species confirmed in the first phase of the project have been catalogued on iNaturalist, with many of them bearing details of local names. “The important part of the project is to evoke interest in the fauna of beaches next to you. You don’t see it because we don’t know the name for it and so it’s not in our consciousness. After we did the iNaturalist guide, a lot of people have been sending us photos; they are seeing more. That’s some nice feedback we have been getting,” he shares.
While the core team — Yuvan, Vikas Madhav, Anooja, Aswathi Asokan, Rohith Srinivasan and Nanditha Ram; all members of the Madras Naturalists Society — has been working on the project, volunteers and friends have been offering assistance from time to time too. “Along our coast, there is extraordinary bivalve and gastropod diversity. That is not at all in our consciousness. We are interested in birds and, now, increasingly about butterflies. But, we have as much inter-tidal life. That’s something we could be more interested in to understand the changes on the beach. The habitat that is most sensitive and vulnerable to climate change is coastal habitats.
An increase in heat or salinity or pollution may affect some species on the coast and not elsewhere. For instance, we found that the ghost crab (if you’ve been to the beach, you would have seen it) is a keystone species; especially being a crucial scavenger. On the beach, microbial life is very low. If there’s dead fish or bird, it will not decompose; it’ll lie there gathering pathogens. So, the most important scavenger in this habitat is the ghost crab. If they were to vanish, our beaches would be far less hygienic,” he explains.
“Coastal biodiversity is the indicator of the region’s health. The coastal environment is a sensitive zone and there are many ways in which it can be destroyed. The local people in these areas are very aware of its importance, the changes that happen there. But, we in the city do not know about it. Documenting this biodiversity is an important step in the conversation of coastal areas,” says Aswathi, a second-year Zoology student who joined the effort about four months ago.
The project also served to highlight the importance of sand dunes in protecting groundwater. In places like Mudhaliar Kuppam and Edayanthittu where there are well-developed sand dunes, you find groundwater right next to the sea. But, in places like north Chennai, where erosion has been triggered, there’s maximum seawater intrusion, says Yuvan, adding that Anna University’s 2019 studies pegged the intrusion at 14 km inland. “Sand dunes act like this osmotic bioshield to push seawater from ingressing into our aquifers. The fisherfolk we spoke to said that they weren’t affected during the tsunami, too, when the sand dunes absorbed it all,” he recounts.
Aswath talks about how this work helped her see the incredible mutual symbiosis across marine/coastal life. She begins with the example of the hermit crab to illustrate it. “If you take the hermit crab, it will live inside the shell of a gastropod; because it has a very soft body. On its shell, you’ll find sea anemone. And you’ll find a host of tunicates (a marine invertebrate) on shells that wash ashore. The decorator worm covers itself in stone, sand and small particles; you won’t be able to see the worm itself. On this pile, you’ll find the gastropods laying eggs. So, no organism lives independently. They are all interconnected,” says Aswathi, who is also part of the Young Naturalists Network.
In the interest of taking all this knowledge to schools students, they are creating a series of learning materials on coastal biodiversity, including species posters and Beach Bingo! “We are making bilingual material for schools in Chennai. So that they will study coastal life far more keenly, which is lacking now despite Chennai being a coastal city. We are doing pocket field guides for children,” he reveals. Phase two — Cuddalore to Nagapattinam — will be launched soon after the lockdown ends, he adds.
To view the findings of phase one, visit: inaturalist.org/guides/13428
On International Day of Biological Diversity, Kannalmozhi Kabilan speaks to eco warriors about their initiative to document the coastal diversity of Tamil Nadu, its pertinence and the learnings they have had in the process
What’s going on?
While phases two, three and four are temporarily on hold, given the lockdown, there is much to do still, it seems. The team is working on a scientific paper to share the findings of the first phase of the project.