CHENNAI: Though climate change and pollution are putting tremendous pressure on the State’s coastline, biodiversity in these areas continue to thrive, finds a study by Madras Naturalist Society (MNS).For the study, five hotspots were selected in North Tamil Nadu coast – Pulicat Lagoon, Adyar Estuary, Kovalam-Muttukadu Backwaters, Odiyur-Mudhaliyarkuppam Lagoon, and Kaliveli Lake.
These locations were selected for their ecological importance. Out of these, Pulicat Lagoon, Kovalam-Muttukadu Backwaters and Kaliveli Lake are designated as Important Coastal and Marine Biodiversity Areas (ICMBAs).MNS’ honourary secretary G Vijay Kumar said: “Out of 913 species from eight classes that were recorded previously from these hotspots, our team were able to spot 709.” The study is the first detailed documentation of the biodiversity of Adyar estuary. Also, though there were studies on the vertebrate diversity of Kaliveli Lake, which is connected to the Bay of Bengal through the Yedaiyanthittu estuary, no study on the crustacean and molluscan diversity has been conducted.
“Thus, the findings of the current study serve as a baseline for this estuary,” he said. Out of the five hotspots studied, Adyar Estuary, Kovalam-Muttukadu Backwaters and Odiyur-Mudhaliyarkuppam Lagoon have little literature on their ecology and biodiversity even though they are rich ecosystems. Adyar Estuary and Odiyur-Mudhaliyarkuppam Lagoon qualify to be declared as ICMBAs based on the findings of this study. The data and discussions aim to serve as a baseline for further studies on these landscapes.
M Yuvan, a member of the study team, said all the five hotspots have recorded rich diversity, but lack adequate protection. For instance, though Kovalam estuary was an identified ICMBA and contains oyster beds and rich biodiversity, it is classified as Coastal Regulation Zone-3 (CRZ-3), instead of CRZ-1A (no development zone). “When it is identified as ICMBA, it must be protected by law,” he said. A total of 34 globally threatened species listed by the International Union for Conservation of Nature (IUCN) are documented from these five hotspots especially from Kaliveli. These species include Indian Skimmer, Great Knot, and the Indian Pangolin.
Also, 25 species of birds endemic to the Indian subcontinent are sighted. Two species of seagrass were recorded in the study area. Large seagrass patches were documented at Pulicat lake, Odiyur lagoon and Kaliveli lake. Areas with seagrass have been designated as CRZ-I(A) zones by the CRZ notification 2019.
The report says the study team has conducted regular field surveys from September 2020 to assess the threats faced by these hotspots.