What Happened
- A new study employed ensemble species distribution models to assess current and future climatic niches for 29 endemic bird species of the Western Ghats.
- Results indicate substantial loss of climatic niche for most species under projected climate change scenarios, with certain species facing more than 70% decline in suitable habitat.
- Four laughingthrush species emerged as exceptionally vulnerable — potentially losing up to 99% of their suitable climatic niche.
- The Nilgiri Wood Pigeon's habitat is projected to see slight increases at lower mountain altitudes by 2021–2040, but sharp decline and fragmentation by 2081–2100 under high-emission scenarios.
- Mid-altitude regions with wet evergreen forest cover are identified as potential climate-change refugia for endemic species.
- Accurate range mapping is identified as critical for conservation planning — inaccurate IUCN range maps have previously left endemic species underprotected.
Static Topic Bridges
Western Ghats: Biodiversity Significance and UNESCO Status
The Western Ghats are a UNESCO World Heritage Site (inscribed 2012) and one of the world's eight "hottest" biodiversity hotspots identified by Conservation International. The range runs approximately 1,600 km along India's western coast from Gujarat to Kerala.
- Flora: ~650 tree species, of which 352 (54%) are endemic.
- Fauna: Amphibians — 179 species, 65% endemic; Reptiles — 157 species, 62% endemic; Fishes — 219 species, 53% endemic.
- At least 325 globally threatened species (IUCN Red List) occur in the Western Ghats — 51 Critically Endangered, 145 Endangered, 129 Vulnerable.
- Flagship mammals: Asian Elephant, Gaur, Tiger, Lion-Tailed Macaque, Nilgiri Tahr, Nilgiri Langur.
- The Western Ghats contain 2 biosphere reserves, 13 national parks, and numerous wildlife sanctuaries.
- The Gadgil Committee (2011) and Kasturirangan Committee (2013) both recommended enhanced ecological protection for the Ghats, though their recommendations remain only partially implemented.
Connection to this news: The Western Ghats' extraordinary endemism means climate-driven habitat contraction does not merely shift species ranges — it eliminates entire populations with no alternative suitable habitat elsewhere on Earth.
Climate Change and Species Distribution: Mechanisms of Habitat Restriction
Climate change alters species' geographical ranges through shifts in temperature and precipitation patterns, affecting the availability of ecologically suitable habitat.
- Species distribution models (SDMs) use bioclimatic variables (temperature, precipitation seasonality, etc.) to project suitable habitats under different emission scenarios (IPCC RCPs/SSPs).
- Range shift patterns: many species are moving poleward and to higher altitudes as climatic zones migrate.
- "Elevational squeeze" — highland species in mountain ranges like the Western Ghats face habitat compression as lower-altitude species move upward, with no new suitable habitat above the summit.
- Ensemble modelling combines multiple SDM algorithms (MaxEnt, BIOCLIM, GLM, etc.) to reduce projection uncertainty.
- IPCC AR6 (2021) finds that 3–14% of species assessed face very high risk of extinction at 1.5°C of global warming, rising sharply at higher temperatures.
Connection to this news: Laughingthrushes and other high-altitude endemics of the Western Ghats are classic elevational squeeze cases — projected losses of up to 99% of climatic niche reflect not just warming but the absence of upward range expansion space.
Biodiversity Hotspots: Conservation Framework
The biodiversity hotspot concept, developed by Norman Myers (1988) and refined by Conservation International, identifies regions with exceptional biodiversity and high levels of habitat destruction as priority areas for conservation investment.
- Criteria for hotspot designation: (1) at least 1,500 endemic vascular plant species and (2) loss of at least 70% of original habitat.
- There are 36 biodiversity hotspots globally, covering about 2.3% of Earth's land surface but containing over 50% of the world's plant species and 42% of terrestrial vertebrates as endemics.
- India has 4 biodiversity hotspots: Western Ghats + Sri Lanka, Indo-Burma, Himalaya, Sundaland (Andaman & Nicobar).
- Convention on Biological Diversity (CBD): India is a signatory; CBD's Kunming-Montreal Global Biodiversity Framework (2022) targets 30x30 — protecting 30% of land and oceans by 2030.
- India's Biological Diversity Act (2002) and National Biodiversity Authority (NBA) govern access and benefit sharing.
Connection to this news: The projected loss of endemic bird habitats in the Western Ghats directly undermines the 30x30 target and India's CBD commitments — especially since the Ghats hotspot is already classified as severely degraded.
Migratory Birds and Climate Change: India's Obligations
While the studied species are resident endemics (not migratory), India's broader bird conservation framework is relevant context.
- India is a signatory to the Convention on Migratory Species (CMS) and the Central Asian Flyway initiative.
- India has 5 Ramsar Wetlands of International Importance in or adjacent to the Western Ghats region.
- The State of India's Birds (SoIB) 2023 report found that 60% of Indian bird species with sufficient data showed population declines.
- High-altitude specialist birds are among the most vulnerable to climate change globally, as confirmed by IPCC and BirdLife International data.
- The Wildlife Protection Act (WPA), 1972 provides Schedule I (highest protection) to several Western Ghats endemic birds including the Nilgiri Laughingthrush.
Connection to this news: The study reinforces the SoIB 2023 finding that high-altitude specialist birds in the Western Ghats are in rapid decline, necessitating climate-adaptive conservation planning beyond current static protected area boundaries.
Key Facts & Data
- Study modelled climatic niches of 29 Western Ghats endemic bird species.
- Laughingthrush species: up to 99% projected loss of suitable climatic niche.
- Western Ghats: UNESCO World Heritage Site (2012); one of 36 global biodiversity hotspots.
- 325 IUCN Red List threatened species in Western Ghats (51 CR, 145 EN, 129 VU).
- Amphibian endemism in Western Ghats: 65% of 179 species.
- India's 4 biodiversity hotspots: Western Ghats+Sri Lanka, Indo-Burma, Himalaya, Sundaland.
- Kunming-Montreal Global Biodiversity Framework (2022): 30x30 target.
- SoIB 2023: 60% of sufficiently-monitored Indian bird species in population decline.
- Nilgiri Laughingthrush: Schedule I protection under Wildlife Protection Act, 1972.