Biodiversity and Conservation — NEET notes

Biodiversity Concept

Biodiversity is the totality of genes, species, and ecosystems in a region. It exists at three levels — genetic diversity (within species), species diversity (between species), and ecological diversity (ecosystem variety). About 1.5 million species are described so far, but estimates range from 5 to 50 million. India alone harbors ~8.1% of global species, making it a megadiversity country.

Described species 1.5 million | Estimated total 5–50 million

Three Levels of Biodiversity

Edward Wilson popularized the term 'biodiversity'. It operates at three nested levels: genetic diversity within species, species diversity within communities, and ecological diversity across landscapes.

Biodiversity (term coined by sociobiologist Edward Wilson) is the variety and variability of life at all levels of biological organization. It's not just 'how many species' — it encompasses variation from the gene level all the way up to entire ecosystems.

• Genetic diversity — Variation in genes WITHIN a species. Example: Rauwolfia vordimia (medicinal plant) shows genetic variation in concentration of the chemical reserpine depending on the Himalayan range it grows in. Rice has 50,000+ genetic varieties in India
• Species diversity — Number and variety of DIFFERENT species in a region. Example: Western Ghats have greater amphibian species diversity than Eastern Ghats
• Ecological (Ecosystem) diversity — Variety of ecosystems (habitats, communities, ecological processes) in a region. Example: India has deserts, rainforests, mangroves, coral reefs, wetlands, alpine meadows — very high ecological diversity

How Many Species?

Only about 1.5 million species have been formally described and given scientific names. Estimates of the true total range from 5 to 50 million. Insects dominate, and most undiscovered species are in the tropics.

According to NCERT, about 1.5 million species have been formally described. Robert May's estimate puts the global total at about 7 million. The range of estimates ( 5 – 50 million) shows how little we know — especially about insects, fungi, and deep-sea organisms.

• Insects are the most species-rich group — over 70% of all recorded animal species. More than 300,000 beetle species alone (J.B.S. Haldane's famous quip: 'God has an inordinate fondness for beetles')
• Plants — ~22% of total described species; angiosperms dominate
• India has ~45,000 plant species and ~91,000 animal species — roughly 8.1% of global species on just 2.4% of land area
• Amazon rainforest alone is home to >40,000 plant species, 1,300 bird species, 3,000 fish species — single most species-rich region on Earth

IUCN Red List

The International Union for Conservation of Nature (IUCN) classifies species into threat categories ranging from Least Concern to Extinct. The Red Data Book is the global database of endangered species.

The IUCN (International Union for Conservation of Nature) maintains the Red List — a comprehensive inventory of the global conservation status of species. Each species is assessed and placed in a threat category based on population size, rate of decline, area of distribution, and extinction probability.

• Extinct (EX) — No known living individual. Example: Dodo, passenger pigeon, Steller's sea cow
• Extinct in the Wild (EW) — Survives only in captivity. Example: some orchid species
• Critically Endangered (CR) — Extremely high risk. Example: Sumatran rhinoceros, Hawksbill turtle
• Endangered (EN) — Very high risk. Example: Bengal tiger, Blue whale, Giant panda
• Vulnerable (VU) — High risk. Example: Hippopotamus, Polar bear
• Near Threatened (NT) — Likely to qualify soon. Example: Jaguar
• Least Concern (LC) — Abundant, widespread. Example: House sparrow (globally), Rat

• The Red Data Book is the document recording endangered and rare species. Different books exist for plants, animals, and other groups
• As of recent assessments, over 40,000 species are threatened with extinction globally
• 784 species have gone Extinct in the last 500 years — including 338 vertebrates, 87 invertebrates, and 359 plants
• India's critically endangered species include: Great Indian Bustard, Pygmy Hog, Gharial, Malabar Civet

India

Only 17 countries are classified as 'megadiverse'. India ranks among them with 4 biodiversity hotspots, diverse climatic zones from Himalayan alpine to tropical rainforest, and over 45,000 plant species.

India is one of the 17 megadiverse countries in the world, harboring about 8.1% of the world's recorded species on just 2.4% of the world's land area. This extraordinary richness comes from India's diverse climatic zones — from the frozen Himalayas to the tropical Western Ghats, from the Thar desert to the rain-soaked northeast.

• ~45,000 plant species and ~91,000 animal species recorded in India
• India has 4 biodiversity hotspots: Western Ghats & Sri Lanka, Himalayas, Indo-Burma, Sundaland (Nicobar Islands)
• Endemism: ~33% of India's recorded plant species are endemic (found nowhere else)
• India lies at the junction of 3 biogeographic realms: Indo-Malayan, Palearctic, and Afro-tropical — this convergence boosts diversity

Patterns of Biodiversity

Biodiversity is not uniformly distributed — it follows striking patterns. Species richness increases from poles to the equator (latitudinal gradient). The species-area relationship (log S = log C + Z log A) predicts how many species an area can hold. Alexander von Humboldt discovered the latitudinal gradient; Z values distinguish mainland (0.1–0.2) from island (0.6–1.2) patterns.

S = C + Z A

Latitudinal Gradient

Species diversity increases as you move from the poles toward the equator. This pattern holds for plants, birds, mammals, insects — almost all groups. Alexander von Humboldt first described this during his South American explorations.

The single most dramatic pattern in biodiversity: species richness increases from the poles to the equator. Colombia (near the equator) has ~1,400 bird species. India (tropical-subtropical) has ~1,300. Greenland (Arctic) has ~56. This latitudinal gradient was first documented by Alexander von Humboldt during his explorations in South America.

• Tropics (23.5°N to 23.5°S) harbor the most species — Amazon alone has >40,000 plant species, 1,300+ bird species, 427 mammal species
• The pattern holds for almost ALL taxonomic groups — plants, birds, mammals, reptiles, insects, fish. Exceptions are rare
• Amazonian forests in South America are the most biodiverse terrestrial habitats on Earth
• Tropical environments remain relatively undisturbed for millions of years — allowing speciation to accumulate diversity

Species-Area Relationship

Alexander von Humboldt observed that within a region, species richness increases with explored area — but follows a logarithmic (not linear) relationship. The equation log S = log C + Z log A quantifies this.

Alexander von Humboldt observed that as you explore a larger area, you encounter more species — but not proportionally. The relationship is logarithmic: doubling the area does NOT double the species. This is captured in the species-area relationship.

S = C + Z A

• S = Species richness (number of species)
• A = Area explored
• Z = Regression coefficient (slope of the line on log-log plot). Typical values: 0.1 to 0.2 for mainland, 0.6 to 1.2 for islands
• C = Y-intercept (depends on the taxonomic group — birds vs mammals vs plants will have different C values)

Why Are Tropics So Species-Rich?

Three main hypotheses explain tropical megadiversity: longer evolutionary time (no glaciation), greater solar energy (higher productivity), and more stable climate (allowing niche specialization).

The tropics are spectacularly diverse — but WHY? This is one of ecology's oldest questions. NCERT gives three main hypotheses, and NEET loves testing them.

• Hypothesis 1: Evolutionary time — Temperate regions were severely affected by repeated glaciations (ice ages). Each glaciation wiped out species and reset the clock. Tropics remained relatively undisturbed for millions of years → more time for speciation → more species accumulated
• Hypothesis 2: Solar energy — Tropics receive more solar energy per unit area year-round. More energy → more productivity → more resources → can support more species with more individuals
• Hypothesis 3: Environmental stability/predictability — Tropical environments are relatively constant (temperature, rainfall). This promotes niche specialization — species can afford to be specialists rather than generalists, leading to more species packed into the same space

Importance of Biodiversity

Biodiversity isn't just nice to have — it's essential for survival. Its value spans direct economic use (food, medicine, timber), indirect ecosystem services (oxygen, pollination, nutrient cycling), and ethical/aesthetic dimensions. Paul Ehrlich's Rivet Popper hypothesis argues that losing species is like removing rivets from an airplane wing — each loss weakens the system until catastrophic failure.

Rivet Popper: Species loss arrow Ecosystem weakening arrow Collapse

Direct Use Values

Humans directly consume or commercially use a huge fraction of biodiversity. 25% of drugs in Western pharma come from plant extracts. Three crops (wheat, rice, maize) feed most of humanity.

Direct use values are benefits we get by directly harvesting or consuming biological resources. These are tangible, marketable products — you can put a price tag on them.

• Food — Only 3 crops (wheat, rice, maize) provide ~60% of global food calories. Humans use ~80,000 plant species for food, but depend heavily on just 12–15 species
• Medicine — 25% of drugs in Western pharmacopoeia are derived from plant extracts. Examples: quinine (from Cinchona — antimalarial), morphine (from opium poppy — painkiller), taxol (from Taxus — anticancer), reserpine (from Rauwolfia — antihypertensive)
• Industrial products — Timber, rubber (from Hevea), resins, dyes, fibers (jute, cotton, silk)
• Genetic resources — Wild relatives of crop species are invaluable for plant breeding. Wild rice varieties carry disease-resistance genes that modern varieties lack

Indirect Use Values

Ecosystem services — oxygen production, pollination, carbon sequestration, water purification, nutrient cycling — are far more valuable than all direct uses combined. Robert Costanza estimated global ecosystem services at $33 trillion/year (1997).

Indirect use values (ecosystem services) are benefits provided by biodiversity that we don't harvest directly — but would collapse without. These invisible services sustain life on Earth and dwarf the economic value of all directly harvested products.

• Oxygen production — Amazon rainforest produces ~20% of world's oxygen through photosynthesis
• Pollination — ~75% of crop species depend on animal pollinators (bees, butterflies, bats). Economic value of pollination: $200+ billion/year globally
• Carbon sequestration — Forests absorb ~2.6 billion tonnes of CO_2 per year, buffering climate change
• Water purification — Wetlands filter pollutants naturally. New York City saved $6–8 billion by protecting its watershed instead of building a water treatment plant
• Nutrient cycling — Decomposers (fungi, bacteria) recycle dead matter into nutrients. Without them, Earth would be buried in dead organisms
• Flood and erosion control — Mangroves protect coastlines. During the 2004 Indian Ocean tsunami, areas with intact mangroves suffered far less damage

Ethical, Aesthetic & Option Values

Beyond economics, biodiversity has intrinsic ethical value (every species has a right to exist), aesthetic value (beauty, ecotourism), and option value (potential future uses we haven't discovered yet).

Not everything is about money. Biodiversity has values that transcend economics — and NCERT explicitly discusses three non-utilitarian perspectives.

• Ethical value (intrinsic value) — Every species has a right to exist regardless of its usefulness to humans. 'Every species is a unique product of millions of years of evolution.' Philosophically, we share Earth with millions of species — they're not ours to destroy
• Aesthetic value — Nature's beauty enriches human life. Ecotourism, bird-watching, nature photography are billion-dollar industries. People pay to see coral reefs, tigers, butterflies — this IS an economic argument for preservation
• Option value — Species we don't yet know how to use may prove invaluable in the future. The next cancer drug, drought-resistant crop gene, or industrial enzyme could be hiding in an undiscovered species. Extinction = permanent loss of options

Rivet Popper Hypothesis

Paul Ehrlich compared species in an ecosystem to rivets in an airplane wing. Losing a few rivets may not crash the plane, but continued loss will eventually cause catastrophic failure. Similarly, each species extinction weakens ecosystem function.

Paul Ehrlich's Rivet Popper Hypothesis uses a brilliant analogy to explain why species loss matters. Imagine an airplane wing held together by thousands of rivets. If a passenger starts removing rivets (= species going extinct), the wing seems fine at first. But eventually, one critical rivet is removed and the wing falls off mid-flight.

• Airplane = Ecosystem
• Rivets = Species in the ecosystem
• Popping rivets = Species extinction due to human activity
• Losing a few rivets (species) from non-critical areas → no visible damage (ecosystem appears stable)
• Losing rivets from a critical section (like the wing = keystone species) → catastrophic failure
• Key insight: we can't predict WHICH species loss will trigger ecosystem collapse — so every species matters

Loss of Biodiversity

We are in the middle of the 6th mass extinction — this time caused entirely by humans. The major drivers of biodiversity loss are captured in HIPPO: Habitat loss (the #1 cause), Invasive species, Pollution, Population growth, and Overexploitation. Co-extinction (when one species dies, its dependent species follow) amplifies the damage. Current extinction rates are 100–1000x the natural background rate.

HIPPO: Habitat loss + Invasive species + Pollution + Population + Overexploitation

6th Mass Extinction

Earth has witnessed 5 mass extinctions, the last wiping out dinosaurs 65 million years ago. The 6th extinction is happening now — driven not by an asteroid but by one species: Homo sapiens. Current extinction rates are 100–1000x the background rate.

Earth has experienced 5 mass extinctions in its history. The most famous: the Cretaceous extinction (65 mya) that killed the dinosaurs. Each time, 50–95% of species vanished. Now, scientists argue we're in a 6th mass extinction — but unlike previous ones caused by asteroids or volcanic eruptions, this one is caused entirely by human activities.

• The current extinction rate is estimated at 100 to 1,000 times the natural background extinction rate
• Since 1500 CE, 784 species have been documented as extinct — including the Dodo (1681), Passenger Pigeon (1914), Thylacine (1936), Steller's Sea Cow (1768)
• 27,000+ species are currently threatened with extinction on the IUCN Red List
• Amphibians are the MOST threatened vertebrate group — ~40% of species declining
• The last mass extinction (Cretaceous, 65 mya) was caused by an asteroid. This one is caused by a single species — us

HIPPO

Edward Wilson identified five major drivers of species extinction: Habitat loss (#1 cause, responsible for most extinctions), Invasive species, Pollution, Population growth, and Overexploitation. NCERT emphasizes habitat loss and fragmentation above all.

The causes of biodiversity loss are summarized by HIPPO (or the 'Evil Quartet' as per NCERT — which lists four main causes). Habitat loss and fragmentation is by far the #1 cause of extinction worldwide.

• H — Habitat loss & fragmentation — THE dominant cause. Tropical rainforests once covered 14% of Earth's land; now reduced to 6%. Amazon loses ~1 million hectares/year. When habitat is fragmented into small patches, species that need large ranges (tigers, elephants) can't survive
• I — Invasive species — Non-native species introduced (deliberately or accidentally) that outcompete, prey upon, or bring disease to native species. Example: Nile perch in Lake Victoria (East Africa) caused extinction of 200+ cichlid fish species. Water hyacinth (Eichhornia) chokes Indian water bodies
• P — Pollution — Pesticides, industrial waste, plastic, oil spills. DDT thinned eggshells of raptors (bald eagle nearly extinct). Acid rain, eutrophication destroy aquatic ecosystems
• P — Population growth (human) — More humans → more resource consumption → more habitat destruction. Human population: 1 billion (1800) → 8 billion (2023). Every additional person means more food, water, space demanded from nature
• O — Overexploitation — Harvesting species faster than they can reproduce. Examples: Steller's Sea Cow (extinct 27 years after discovery), many whale species, passenger pigeon, overfishing of cod, tuna

Co-extinction

Species don't exist in isolation. When a host species goes extinct, all its obligate parasites, pollinators, and symbionts follow. This cascade effect means actual extinction numbers are far higher than direct counts suggest.

Co-extinction occurs when a species goes extinct because the species it depended on went extinct first. This is the domino effect of extinction — and it means the true toll of biodiversity loss is far worse than the number of directly extinct species suggests.

• When a host fish species goes extinct, all its unique parasites (that are obligate = can't survive on any other host) also go extinct. These parasite extinctions are never counted in official numbers
• When a plant species goes extinct, all the insect species that co-evolved with it and depend exclusively on it for food go extinct too
• Mutualistic co-extinctions — A fig tree species and its specific pollinator wasp CANNOT survive without each other. Lose one, and you lose both
• Co-extinction is sometimes called the 'domino effect' or 'cascade of extinctions'

Conservation Strategies

Conservation operates on two fronts: in-situ (protecting species in their natural habitat — national parks, wildlife sanctuaries, biosphere reserves, sacred groves) and ex-situ (protecting species outside their habitat — zoos, botanical gardens, seed banks, cryopreservation). India has 18 biosphere reserves, 106 national parks, 567+ wildlife sanctuaries, and some of the oldest sacred groves in the world.

In-situ (in habitat) + Ex-situ (outside habitat) = Complete conservation strategy

In-Situ Conservation

The best way to conserve biodiversity is to protect the entire ecosystem in its natural state. This includes national parks (strictest protection), wildlife sanctuaries (some human activity allowed), and biosphere reserves (large multi-zone areas).

In-situ conservation means protecting species in their natural habitat — the ecosystem where they evolved. This is the most effective approach because it conserves not just individual species but the entire web of interactions (predator-prey, pollinator-plant, decomposer cycles) that keep the ecosystem functioning.

• National Parks — Strictest protection. No hunting, grazing, forestry, or habitat destruction allowed. India has 106 national parks. Examples: Jim Corbett (first in India, 1936), Kaziranga (one-horned rhino), Gir (Asiatic lion), Ranthambore (tigers)
• Wildlife Sanctuaries — Some human activities (like grazing, timber collection) allowed if they don't harm wildlife. India has 567+ wildlife sanctuaries. Example: Bharatpur Bird Sanctuary (Keoladeo), Periyar (elephants)
• Biosphere Reserves — Large areas with multiple zones: core (no disturbance), buffer (limited activity), transition (sustainable human settlement). India has 18 biosphere reserves. Example: Nilgiri (first in India, 1986), Sunderbans, Nanda Devi, Gulf of Mannar
• Reserved & Protected Forests — Managed forests where some human use is permitted under forest department supervision

Sacred Groves

Sacred groves are forest patches protected by local communities for religious or cultural reasons, often for centuries. They are repositories of rare and endemic species and represent one of humanity's oldest conservation strategies.

Sacred groves are patches of forest protected by local communities through religious beliefs and taboos. Cutting trees, hunting, and any disturbance in these groves is forbidden by community tradition — not by government law. They've been protecting biodiversity for centuries, long before modern conservation was invented.

• Found across India — Khasi and Jaintia hills (Meghalaya), Western Ghats (Karnataka, Kerala), Rajasthan, Madhya Pradesh, Maharashtra
• In Meghalaya, sacred groves are called 'Law kyntang' or 'Law lyngdoh' — protected by the Khasi tribe
• In Rajasthan, the Bishnoi community has protected blackbuck, chinkara, and khejri trees for centuries as religious duty
• Sacred groves often harbor rare and endemic species that have disappeared from surrounding unprotected areas
• India has an estimated 100,000+ sacred groves — an incredibly vast network of community-based conservation

Ex-Situ Conservation

When species are too threatened to survive in the wild, we bring them to safety outside their natural habitat — in zoos, botanical gardens, seed banks, and cryopreservation facilities. Think of it as creating backup copies of species.

Ex-situ conservation means protecting species outside their natural habitat in controlled environments. This is the emergency backup plan — used when a species is too endangered to survive in the wild, or when its habitat has been destroyed.

• Zoological parks (Zoos) — Captive breeding of endangered animals. Success stories: Pygmy hog, California condor, Arabian oryx, Giant panda. The goal is always to eventually reintroduce animals to the wild
• Botanical gardens — Living collections of rare and endangered plants. India has major ones at Kolkata (Indian Botanic Garden, oldest in Asia), Lucknow (NBRI), Ooty, Shimla
• Seed banks — Seeds of thousands of plant varieties stored under controlled temperature and humidity for decades. Global example: Svalbard Global Seed Vault (Norway) stores 1.1+ million seed samples from every country — nicknamed the 'Doomsday Vault'
• Cryopreservation — Storing gametes (sperm, eggs), embryos, and tissues at ultra-low temperatures ( -196°C in liquid nitrogen). DNA remains viable for decades
• Tissue culture — Growing entire plants from tiny tissue samples in labs. Used for rare orchids, medicinal plants, and endangered tree species

International Conventions & Indian Laws

Global conservation efforts are coordinated through international agreements like the Convention on Biological Diversity (CBD, 1992) and CITES. India protects biodiversity through the Wildlife Protection Act (1972), Forest Conservation Act (1980), and Biodiversity Act (2002).

Conservation needs legal force. International agreements set global goals, while national laws provide enforcement. India has been a signatory to most major biodiversity conventions and has enacted some of Asia's strongest wildlife protection laws.

• Convention on Biological Diversity (CBD) — Signed at the Earth Summit in Rio de Janeiro, 1992. Goals: conservation of biodiversity, sustainable use, equitable sharing of benefits from genetic resources. India ratified it in 1994
• CITES (Convention on International Trade in Endangered Species) — Regulates international trade of wild animals and plants. Species listed in Appendix I (most endangered) cannot be traded commercially at all
• World Summit on Sustainable Development (Johannesburg, 2002) — Pledged to reduce biodiversity loss significantly by 2010
• India's Wildlife Protection Act, 1972 — Legal framework for protecting wild animals and plants. Created the network of national parks and sanctuaries. Bans hunting of endangered species
• India's Biological Diversity Act, 2002 — Protects India's biological resources and traditional knowledge. Established the National Biodiversity Authority (NBA)

Biodiversity Hotspots

Biodiversity hotspots are regions with exceptionally high endemic species that are under extreme threat. To qualify, a region must have at least 1,500 endemic vascular plant species AND must have lost at least 70% of its original habitat. There are 34–36 recognized hotspots worldwide covering just 2.3% of Earth's land area but harboring ~50% of all plant species. India has 4 hotspots: Western Ghats & Sri Lanka, Himalayas, Indo-Burma, and Sundaland (Nicobar Islands).

Hotspot criteria: 1500 endemic plant species + 70 % habitat loss

Hotspot Criteria

Norman Myers (1988) coined the concept of biodiversity hotspots. A region qualifies if it has at least 1,500 endemic vascular plant species AND has lost 70% or more of its original natural vegetation. Both conditions must be met.

The concept of biodiversity hotspots was introduced by British ecologist Norman Myers in 1988. A hotspot is not just a species-rich area — it must be both exceptionally rich in endemic species AND exceptionally threatened. Two strict criteria must be met simultaneously.

• Criterion 1: Endemism — Must contain at least 1,500 species of vascular plants (>0.5% of the world's total) as endemics (found nowhere else on Earth)
• Criterion 2: Threat — Must have lost at least 70% of its original primary vegetation (habitat). This means the region is under extreme human pressure
• Both criteria must be met — A species-rich forest that's not threatened is NOT a hotspot. A heavily damaged region with few endemic species is NOT a hotspot
• Currently 34 to 36 recognized hotspots globally (the number increases as more regions are assessed)
• These hotspots cover just 2.3% of Earth's land area but harbor ~50% of all flowering plant species and ~42% of all terrestrial vertebrate species as endemics

Global Hotspots

The 34–36 biodiversity hotspots are distributed across all continents but concentrated in tropical and subtropical regions. Together they originally covered 15.7% of Earth's land but have been reduced to 2.3% through habitat destruction.

Biodiversity hotspots are scattered across the globe but are disproportionately concentrated in tropical and subtropical regions — especially mountainous areas with diverse microclimates. Together, they tell a story of extraordinary richness under extraordinary threat.

• Top hotspots globally: Tropical Andes (richest of all — 30,000 endemic plants), Sundaland (SE Asia), Madagascar, Atlantic Forest (Brazil), Western Ghats & Sri Lanka, Caribbean Islands
• Hotspots collectively held ~15.7% of Earth's land area originally, but now reduced to just ~2.3% (85% of habitat already destroyed)
• ~50% of all vascular plant species and ~42% of all vertebrate species are endemic to these hotspots
• Tropical Andes is the single richest hotspot with ~30,000 endemic plant species — more than any other region
• Madagascar has ~90% endemism in plants — nearly everything found there is found NOWHERE else

India's 4 Hotspots

India is represented in 4 of the world's 36 biodiversity hotspots. The Western Ghats & Sri Lanka hotspot and the Eastern Himalayas are the most prominent, harboring thousands of endemic species found nowhere else on Earth.

India is fortunate to have parts of 4 global biodiversity hotspots within its borders — a testament to the country's extraordinary ecological diversity spanning from the Himalayas to the tropical Western Ghats.

• Western Ghats & Sri Lanka — ~5,000 flowering plant species (~1,700 endemic). Home to Lion-tailed Macaque, Nilgiri Tahr, Malabar Giant Squirrel, hundreds of endemic amphibians. Lost ~70% of original forest. UNESCO World Heritage Site (2012)
• Himalayas — Stretches across Pakistan, India, Nepal, Bhutan, China. Contains ~10,000 plant species (~3,160 endemic). Snow leopard, Red panda, Himalayan musk deer are iconic endemic/near-endemic species
• Indo-Burma — Covers NE India, Myanmar, Thailand, Vietnam, southern China. Extremely rich in freshwater fish species. NE India is the 'orchid paradise of India' with 900+ orchid species
• Sundaland — Includes Nicobar Islands (India's share). One of the richest hotspots for plant diversity. Orangutans, Sumatran tigers, Rafflesia (world's largest flower) are found here

Endemism

Endemic species are restricted to a specific geographic region and found nowhere else. They're the first to go extinct when habitats are destroyed because they have no backup populations elsewhere. High endemism is a key criterion for hotspot designation.

A species is endemic to a region if it is naturally found only there and nowhere else on Earth. Endemic species are evolution's unique creations — shaped by the specific conditions of their home region over millions of years. They're also the most vulnerable to extinction because if their one habitat is destroyed, they have nowhere to go.

• Endemic species of India — Lion-tailed Macaque (Western Ghats), Nilgiri Tahr (Western Ghats), Indian Giant Squirrel (Western Ghats), Sangai deer (Manipur only), Kashmir Stag/Hangul (Kashmir only)
• Why islands have high endemism — Geographic isolation means species evolve independently. Madagascar: ~90% plant endemism. Australia: kangaroos, platypus, koalas. Galapagos: Darwin's finches. Hawaii: ~90% of its native birds are endemic
• India's endemism — ~33% of flowering plants and ~53% of freshwater fish species in India are endemic
• Western Ghats amphibian endemism — ~80% of amphibian species in the Western Ghats are endemic — one of the highest rates globally for any continental area