Tamil Nadu's 3 Biosphere Reserves: Nilgiri (1986), Gulf of Mannar (1989), Agasthyamala (2001)

3 November 2026 · English Environment & Ecology

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Topics: Environment · 3 November 2026 Current Affairs (UPSC / TNPSC / SSC / RRB)

News

3 November is the International Day for Biosphere Reserves. It turns the spotlight on Tamil Nadu's three biosphere reserves: (1) the Nilgiri Biosphere Reserve (1 Sept 1986) – about 5,520 sq km at the trijunction of Tamil Nadu, Kerala and Karnataka; (2) the Gulf of Mannar Biosphere Reserve (notified 4 April 1989) – about 10,500 sq km from Rameswaram to Kanyakumari, with the 21-island Marine National Park (1986) as its core; (3) the Agasthyamala Biosphere Reserve (2001) – 3,500.36 sq km shared by Tamil Nadu and Kerala, added to UNESCO's World Network in 2016.

Key facts

Nilgiri	1986; ~5,520 sq km; TN–Kerala–Karnataka; where the Western and Eastern Ghats meet
Nilgiri – protected areas	Mudumalai, Mukurthi, Silent Valley, Wayanad, Bandipur, Nagarhole, Siruvani hills, Nilambur slopes
Gulf of Mannar	Biosphere Reserve 1989 (~10,500 sq km); Marine National Park 1986 (G.O. 962; 560 sq km)
21 islands – 4 groups	Mandapam (7), Keelakarai (7), Vembar (3), Tuticorin (4); a chain about 160 km long
Agasthyamala	2001; UNESCO network 2016; Kerala 1,828 + TN 1,672.36 sq km
Agasthyamala – areas	Neyyar, Peppara, Shendurney sanctuaries (Kerala) + Kalakad–Mundanthurai Tiger Reserve (TN)

Background

• What is a biosphere reserve: a large land or marine area that conserves biodiversity while supporting the livelihoods of people living there. It is divided into three zones – core, buffer and transition.
• Geography – Nilgiri: it lies where the Western Ghats meet the Eastern Ghats. Mudumalai and Mukurthi (Tamil Nadu), Silent Valley and Wayanad (Kerala), and Bandipur and Nagarhole (Karnataka) are part of it.
• Marine ecology – Gulf of Mannar: 21 uninhabited islands lie 2–10 km off the coast, from Mandapam to Tuticorin. It has over 4,000 species, including 117 coral and 14 seagrass species.
• Agasthyamala & the Kani tribe: the Kani (Kanikkar) are its ancient tribal people. From 'Arogyapacha' (Trichopus zeylanicus), a plant they used, TBGRI, Thiruvananthapuram, developed the drug 'Jeevani' (1995); 50% of the licence fee and royalty went to the Kanis – a model of benefit sharing for traditional knowledge.

Tamil Nadu link: all three biosphere reserves include Tamil Nadu territory – Nilgiri (hills), Gulf of Mannar (sea) and Agasthyamala (Tirunelveli and Kanyakumari districts). The Tamil Nadu government declared the Gulf of Mannar Marine National Park by G.O. No. 962 on 10 Sept 1986.

Source: Ramanathapuram District website (ramanathapuram.nic.in); Nilgiri Natural History Society (nnhs.in); Down To Earth (Kani, Jeevani); CBD (cbd.int) TBGRI benefit-sharing case study; Wikipedia (Agasthyamala)

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