Kerala and the Western Ghats — Biodiversity Hotspot, Silent Valley, Nilgiri Biosphere, and Kasturirangan Report

The Western Ghats is one of the world’s 36 biodiversity hotspots and a UNESCO World Heritage Site. Kerala’s entire eastern boundary runs along the Western Ghats, making this a core PSC topic.

1. Western Ghats — Overview

Parameter	Detail
Length	About 1,600 km (from Gujarat’s Tapti Valley to Kanyakumari, Tamil Nadu)
States covered	Gujarat, Maharashtra, Goa, Karnataka, Kerala, Tamil Nadu
Also known as	Sahyadri
UNESCO World Heritage Site	2012 (39 serial sites across 4 states — Kerala, Karnataka, Tamil Nadu, Maharashtra)
Biodiversity hotspot	One of the world’s 8 “hottest hotspots” (Norman Myers concept)
Average elevation	900-1,500 m; highest peaks above 2,500 m
Highest peak in Western Ghats	Anamudi (2,695 m) in Idukki, Kerala — also the highest peak in South India
Second highest peak	Doddabetta (2,637 m) in Nilgiris, Tamil Nadu
Major gaps (passes)	Thal Ghat (Mumbai-Nashik), Bhor Ghat (Mumbai-Pune), Palakkad Gap (Palakkad, Kerala — widest gap, ~30 km)

PSC Favourite: “Highest peak in the Western Ghats?” — Anamudi (2,695 m), Idukki, Kerala.

2. Biodiversity Hotspot — Why the Western Ghats Qualify

Criterion	Detail
Definition of hotspot	Region with at least 1,500 endemic vascular plant species AND has lost at least 70% of original habitat
Endemic plant species	Over 5,000 flowering plant species; about 1,700+ are endemic
Endemic fauna	325+ globally threatened species (IUCN Red List)
Age	Over 150 million years old (predating the Himalayas)
Climate role	Intercepts moisture-laden southwest monsoon winds; crucial for peninsular India’s rainfall

3. Nilgiri Biosphere Reserve (NBR)

Parameter	Detail
Established	1986 — India’s first Biosphere Reserve
UNESCO MAB recognition	2000 (Man and the Biosphere Programme)
Area	5,520 sq km
States covered	Tamil Nadu, Kerala, Karnataka
Core zone includes	Mudumalai (TN), Bandipur (Karnataka), Nagarhole (Karnataka), Wayanad (Kerala), Silent Valley (Kerala)
Major tribes	Todas, Kotas, Irulas, Kurumbas, Paniyar, Kattunaickans
Key species	Nilgiri Tahr, Lion-tailed Macaque, Nilgiri Langur, Indian Elephant, Tiger

4. Silent Valley National Park

Parameter	Detail
Location	Palakkad district, Kerala
Area	89.52 sq km (core)
Declared National Park	1984
Significance	One of the last undisturbed tracts of tropical evergreen forest in India
Famous for	Lion-tailed Macaque (Macaca silenus) — flagship species; one of the world’s most endangered primates
Silent Valley Movement	1970s-1980s: People’s movement against the proposed Kunthipuzha Hydroelectric Project (Silent Valley Dam); movement succeeded — dam was shelved by PM Indira Gandhi in 1983
River	Kunthipuzha (tributary of Bharathapuzha)
Buffer zone	Karimpuzha Wildlife Sanctuary
No tribal habitation inside	Unique feature — no permanent settlements inside the park

PSC Favourite: “Silent Valley is famous for which primate?” — Lion-tailed Macaque.

5. Kasturirangan Report (2013)

Aspect	Detail
Full name	Report of the High Level Working Group on Western Ghats Ecology
Chairman	Dr. K. Kasturirangan (former ISRO chairman)
Submitted	April 2013 (to Ministry of Environment)
Background	Followed the Gadgil Committee Report (2011) chaired by Prof. Madhav Gadgil
Key recommendation	Identified 37% of the Western Ghats as Ecologically Sensitive Area (ESA) — about 60,000 sq km
Gadgil vs Kasturirangan	Gadgil recommended the ENTIRE Western Ghats as ESA (3 zones); Kasturirangan was a more pragmatic/diluted version
ESA restrictions	Ban on mining, quarrying, and red-category industries in ESA; regulated construction
Controversy in Kerala	Widespread protests by farmers and plantation workers fearing livelihood loss; many felt ESA boundaries were too restrictive
Draft notifications	Multiple draft ESA notifications issued (2014, 2018, 2022); final notification still pending as of 2026

Gadgil vs Kasturirangan — Comparison

Feature	Gadgil Committee (2011)	Kasturirangan Report (2013)
Chairman	Prof. Madhav Gadgil	Dr. K. Kasturirangan
ESA extent	Entire Western Ghats (3 zones: ESZ 1, 2, 3)	37% of Western Ghats (~60,000 sq km)
Approach	Precautionary — maximum protection	Balanced — development + conservation
Mining	Complete ban in ESZ 1	Ban in ESA only
States’ reaction	Strongly opposed by most states	Relatively more acceptable
Implementation	Not implemented	Partially under implementation (draft notifications)

6. Protected Areas in Kerala’s Western Ghats

Protected Area	District	Area (sq km)	Key Feature
Silent Valley NP	Palakkad	89.52	Tropical evergreen; Lion-tailed Macaque
Eravikulam NP	Idukki	97	Nilgiri Tahr (largest population); Neelakurinji blooms every 12 years
Periyar Tiger Reserve	Idukki	925	Periyar Lake; elephants, tigers
Wayanad Wildlife Sanctuary	Wayanad	344.44	Part of Nilgiri Biosphere; elephants, tigers
Parambikulam Tiger Reserve	Palakkad/Thrissur	643.66	Kannimara Teak — oldest teak tree in Asia
Chinnar Wildlife Sanctuary	Idukki	90.44	Dry deciduous forest; grizzled giant squirrel
Muthanga Wildlife Sanctuary	Wayanad	Part of WLS	Elephant corridor
Aralam Wildlife Sanctuary	Kannur	55	Only wildlife sanctuary in Kannur district
Peppara Wildlife Sanctuary	Thiruvananthapuram	53	Near Ponmudi
Shendurney Wildlife Sanctuary	Kollam	100	Near Thenmala; tropical forests

7. Endemic Species of the Western Ghats (Kerala)

Endemic Mammals

Species	Key Fact
Nilgiri Tahr (Nilgiritragus hylocrius)	State animal of Tamil Nadu; Eravikulam NP has the largest population; IUCN Endangered
Lion-tailed Macaque (Macaca silenus)	Only about 4,000 in the wild; IUCN Endangered; Silent Valley flagship
Nilgiri Langur (Trachypithecus johnii)	Endemic to Western Ghats; IUCN Vulnerable
Malabar Large-spotted Civet	Extremely rare; possibly extinct; last confirmed sighting 1990
Nilgiri Marten	Only species of marten in South India
Brown Palm Civet	Endemic to Western Ghats

Endemic Birds

Species	Key Fact
Malabar Grey Hornbill	Common in Kerala’s forests
Nilgiri Flycatcher	Endemic; montane forests
Nilgiri Pipit	High-altitude grasslands of the Western Ghats
White-bellied Shortwing	Shola forests
Malabar Trogon	Colourful; evergreen forests
Malabar Parakeet	Endemic to Western Ghats
Rufous Babbler	Dense undergrowth of Western Ghats

Endemic Amphibians

Fact	Detail
Purple Frog (Nasikabatrachus sahyadrensis)	Discovered 2003; “living fossil” — closest relative in Seychelles; burrows underground
Amphibian endemism	Over 179 species of amphibians endemic to the Western Ghats

Endemic Plants

Species	Key Fact
Neelakurinji (Strobilanthes kunthiana)	Blooms once every 12 years; Eravikulam NP; last bloom: 2018; next: 2030
Vateria indica (White Dammar)	Important timber tree; endemic
Dipterocarpus species	Tropical evergreen forests
Various orchid species	Over 300 orchid species, many endemic

8. Threats to the Western Ghats in Kerala

Threat	Detail
Encroachment	Agricultural expansion into forest fringes
Quarrying and mining	Illegal quarrying of granite, laterite; contributes to landslides
Monoculture plantations	Rubber, tea, coffee plantations replaced natural forests
Human-wildlife conflict	Elephant and wild boar crop raids; retaliatory killings
Invasive species	Lantana camara, Mikania micrantha (mile-a-minute weed) — smother native plants
Climate change	Shifting rainfall patterns, increasing temperature, reducing cloud forests
Landslides	2018, 2019, 2024 Kerala floods linked to deforestation and Western Ghats degradation
Road construction	Widening of highways through forests fragments habitats

9. Previous Year PSC-Style Questions

Question	Answer
Highest peak in South India?	Anamudi (2,695 m), Idukki
First Biosphere Reserve in India?	Nilgiri Biosphere Reserve (1986)
Silent Valley is in which district?	Palakkad
Lion-tailed Macaque is the flagship species of?	Silent Valley National Park
Kasturirangan Report recommended what percentage of Western Ghats as ESA?	37%
Who chaired the Western Ghats Ecology Expert Panel (2011)?	Prof. Madhav Gadgil
Neelakurinji blooms once every?	12 years
Western Ghats UNESCO World Heritage status was given in?	2012
The Palakkad Gap is the widest gap in?	The Western Ghats
Nilgiri Tahr is found mainly in?	Eravikulam National Park
Purple Frog was discovered in?	2003
Kannimara Teak is in which tiger reserve?	Parambikulam Tiger Reserve
The river flowing through Silent Valley is?	Kunthipuzha
The Silent Valley dam project was shelved by?	PM Indira Gandhi (1983)