NCERT grounding
This subtopic sits inside section 13.2.2 of the NCERT Class 12 chapter Biodiversity and Conservation, under the discussion of in-situ conservation. Faced with the conflict between development and conservation, many nations find it economically unrealistic to conserve all their biological wealth — the number of species waiting to be saved far exceeds the conservation resources available. To address this on a global scale, eminent conservationists identified, for maximum protection, certain biodiversity hotspots: regions with very high levels of species richness and a high degree of endemism, that is, species confined to that region and not found anywhere else.
The NCERT text records the precise numbers a NEET aspirant must memorise. Initially 25 biodiversity hotspots were identified; subsequently nine more were added, bringing the total number of biodiversity hotspots in the world to 34. The chapter also notes that India's history of religious and cultural traditions emphasised protection of nature, leading to sacred groves — tracts of forest set aside, with all trees and wildlife within venerated and given total protection.
"Although all the biodiversity hotspots put together cover less than 2 per cent of the earth's land area, the number of species they collectively harbour is extremely high."
NCERT Class 12 Biology · Section 13.2.2
Biodiversity hotspots in depth
The concept of biodiversity hotspots was given by the ecologist Norman Myers. It is a strategic answer to a practical problem: conservation budgets and trained manpower are limited, yet the threat to species is global and accelerating. Rather than spread thin protection uniformly across all of Earth's land, hotspot theory directs intensive effort to the small set of regions where the conservation return on investment is greatest. A hotspot is, in effect, a triage category for the planet's biodiversity.
A region qualifies as a hotspot only when it satisfies a strict combination of conditions. It must show very high species richness — a large absolute number of species in the area. It must also show a high degree of endemism: a large proportion of those species must be endemic, meaning confined to that region and found nowhere else on Earth. Endemism is the decisive criterion, because endemic species cannot be conserved anywhere else — if their single home is destroyed, they are lost globally. Finally, a hotspot must be a region of accelerated habitat loss, so it is under serious and immediate threat. Richness and endemism describe what is at stake; threat describes why action cannot wait.
Three defining conditions. All three must hold together — a region rich in species but with no endemics, or rich and endemic but not threatened, does not qualify as a hotspot.
Species richness
A very high absolute number of plant and animal species packed into the region.
High endemism
A large share of the species are endemic — confined to that region and found nowhere else.
Accelerated threat
The region is undergoing rapid habitat loss, so protection is urgent.
The number of recognised hotspots has changed over time, and NEET examiners exploit this. Initially, 25 biodiversity hotspots were identified in the world. This number was subsequently raised: nine more regions were added, bringing the total to 34 biodiversity hotspots. The NCERT Class 12 text uses the figure 34, and that is the value expected in current exams. The older NIOS material still cites the original 25 — a discrepancy worth noting, but for NEET the answer is 34.
Of Earth's land area
All 34 hotspots together cover less than 2 per cent of the Earth's land surface, yet the number of species they collectively harbour is extremely high. Strict protection of these hotspots could reduce the ongoing mass extinctions by almost 30 per cent.
That pairing of numbers is the single most powerful argument for the hotspot strategy. Because endemic species are geographically concentrated, safeguarding a small area shields an outsized fraction of global biodiversity. This is why hotspots have become a central tool of in-situ conservation, and why the chapter places the discussion under in-situ conservation. Note also that hotspots are not simply the regions of highest species count — the Amazon rainforest holds the greatest biodiversity on Earth, yet a hotspot specifically combines richness with endemism and threat. The label is about prioritising rescue, not ranking abundance.
Figure 1. Hotspots cover under 2 per cent of land, yet their strict protection could cut ongoing mass extinctions by nearly 30 per cent — the disproportion that justifies the strategy.
The three Indian hotspots
Of the 34 global hotspots, three cover India's exceptionally high biodiversity regions, totally or partially. NEET frequently asks students to name or count these, so the trio must be memorised exactly: the Western Ghats and Sri Lanka, the Indo-Burma region, and the Himalaya. Each is also a region of accelerated habitat loss, which is precisely what makes it a hotspot rather than merely a biodiversity-rich area.
Three for India. Western Ghats and Sri Lanka, Indo-Burma, and Himalaya — these cover India's biodiversity-rich regions totally or partially.
Western Ghats & Sri Lanka
The Western Ghats run along peninsular India's west coast and hold high amphibian diversity; the hotspot extends to Sri Lanka.
Indo-Burma
Spanning north-eastern India and neighbouring regions, an area exceptionally rich in flowering plants and fauna.
Himalaya
The mountain belt with deep valleys rich in endemic plants, covering India's northern high-altitude biodiversity.
India's significance extends beyond hotspots. Although India has only 2.4 per cent of the world's land area, its share of global species diversity is 8.1 per cent, making it one of the 12 mega-diversity countries of the world. The three Indian hotspots concentrate much of this wealth. A common exam point is the distinction between a mega-diversity country — a national-level descriptor — and a hotspot, a defined region with richness, endemism and threat.
Sacred groves of India
India's conservation story is not only institutional; it is also cultural. The chapter records that India has a long history of religious and cultural traditions that emphasised protection of nature. In many cultures, tracts of forest were set aside, and all the trees and wildlife within were venerated and given total protection. These protected forest tracts are called sacred groves. They are forests preserved on religious and cultural grounds rather than by law alone — cutting trees, hunting and other interference are prohibited because the grove and its life are held sacred.
Sacred groves are a textbook example of traditional, community-based in-situ conservation. Because the whole forest tract is protected within its natural habitat, the biodiversity it contains is conserved on site — exactly the principle of in-situ conservation. They also demonstrate community participation in conservation: protection comes from the beliefs and practices of local people, not from a government enclosure. This is why sacred groves are classified as in-situ, never ex-situ.
Sacred grove locations in India
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Region 1
Khasi & Jaintia Hills
In Meghalaya — here the sacred groves are the last refuges for many rare and threatened plants.
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Region 2
Aravalli Hills
In Rajasthan — sacred forest tracts protected by local tradition.
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Region 3
Western Ghat regions
In Karnataka and Maharashtra — groves within the biodiversity-rich Ghats.
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Region 4
Sarguja, Chanda & Bastar
In Madhya Pradesh — traditionally venerated and protected forest patches.
The conservation value of sacred groves is considerable. In Meghalaya, the sacred groves are the last refuges for a large number of rare and threatened plants — species that may have disappeared elsewhere survive within these venerated tracts. Sacred groves thus function as small, undisturbed sanctuaries embedded in heavily used landscapes, protecting the whole assemblage of forest wildlife along with the trees.
Figure 2. The four sacred grove regions named by NCERT — protected by religious and cultural tradition, with the Meghalaya groves serving as the last refuge for many rare and threatened plants.
Worked examples
Why does the protection of biodiversity hotspots give a disproportionately large conservation benefit relative to their land area?
Hotspots are defined by high endemism — a large share of their species are confined to that region and found nowhere else. Endemic species are geographically concentrated, so a small protected area can shelter a very large fraction of global biodiversity. The 34 hotspots together cover less than 2 per cent of Earth's land, yet their strict protection could reduce the ongoing mass extinctions by almost 30 per cent. The disproportion arises directly from endemism: protecting the one place a species lives saves it everywhere.
Sacred groves are sometimes wrongly grouped with botanical gardens. Explain why sacred groves belong to in-situ conservation.
In-situ conservation protects organisms within their natural habitat by conserving the whole ecosystem. A sacred grove is a tract of natural forest set aside on religious and cultural grounds, with all its trees and wildlife venerated and protected on site. Because the entire forest and its biodiversity remain in place, sacred groves are in-situ conservation. Botanical gardens and zoological parks, by contrast, keep species outside their natural habitat in a managed setting, so they are ex-situ. Sacred groves are also a fine example of community participation in in-situ conservation.
How many biodiversity hotspots are currently recognised worldwide, and how did this number change?
Initially 25 biodiversity hotspots were identified in the world. Subsequently nine more were added, raising the total to 34 biodiversity hotspots. For NEET, the current and expected answer is 34, the figure used by the NCERT Class 12 text. Three of these — the Western Ghats and Sri Lanka, the Indo-Burma region and the Himalaya — cover India's biodiversity-rich regions.
Common confusion & NEET traps
Most errors on this subtopic come from confusing two pairs of ideas: hotspots versus regions of highest biodiversity, and sacred groves versus ex-situ methods. The numbers also trip students — examiners deliberately offer 25 as a distractor when the expected answer is 34, and vice versa, depending on which source they cite.
In-situ conservation
On-site, whole ecosystem protected
- Biosphere reserves, national parks, wildlife sanctuaries
- Sacred groves — community-based, religious protection
- Biodiversity hotspots are a global in-situ strategy
- Species protected in their natural habitat
Ex-situ conservation
Off-site, away from natural habitat
- Zoological parks, botanical gardens, wildlife safari parks
- Seed banks, cryopreservation, in-vitro fertilisation
- Tissue culture propagation of plants
- Species protected in a special managed setting