Biodiversity and Conservation

Biodiversity (Biological Diversity): • The variety and variability of life on Earth at all levels — from genes within a species to the variety of ecosystems • Term coined by Walter G. Rosen (1985); popularised by E.O. Wilson • Includes all living organisms: plants, animals, fungi, microorganisms, and their interactions • Current estimated species: ~8.7 million (described: ~1.5 million) Three levels of biodiversity: 1. Genetic Diversity: • Variation in DNA sequences among individuals of the same species • Also: variation between populations of the same species in different geographic areas • Basis for evolution — provides raw material for natural selection • Examples: – India has >50,000 genetically diverse strains of rice (Oryza sativa) – Mango has 1000+ varieties (Langra, Alphonso, Dussehri, etc.) — all Mangifera indica – Human populations show genetic diversity in blood types, HLA, disease resistance • Low genetic diversity → increased vulnerability to disease (e.g., Irish potato famine, 1845) 2. Species Diversity: • Variety of different species in a given area • Two components: (a) Species richness: Number of different species in an area (b) Species evenness: Relative abundance of individuals of each species • Measured by diversity indices (Shannon index, Simpson's index) • Examples: – Western Ghats has greater amphibian diversity than Eastern Ghats – Tropical regions have higher species diversity than temperate/polar regions – Amazon rainforest: highest species diversity 3. Ecological (Ecosystem) Diversity: • Variety of different ecosystems (habitats, communities, ecological processes) in a given area • At the landscape level — diversity of habitat types • India has: tropical rainforests, deserts, mangroves, wetlands, coral reefs, alpine meadows, grasslands • Higher ecosystem diversity → higher species diversity (more niches available) • Includes diversity of ecological processes: nutrient cycling, energy flow, succession

Biodiversity is essential for ecosystem functioning for several reasons: 1. Ecosystem productivity and biomass: • Higher species diversity → higher primary productivity (more efficient use of resources) • Different species use different resources → reduce competition, increase total ecosystem productivity • Experiment by Tilman: grassland plots with more plant species had higher total biomass 2. Stability and resilience: • More diverse communities are more stable (resistance to disturbance) • Biodiversity insurance hypothesis: Many species provide 'insurance' — if one fails, others with similar functions maintain ecosystem services • Stability increases with species richness (rivet-popper hypothesis by Ehrlich) 3. Nutrient cycling: • Diverse decomposers (fungi, bacteria) ensure complete decomposition of all types of organic matter • Multiple species performing each step of nutrient cycling ensures no bottlenecks 4. Ecosystem services provided by biodiversity: • Provisioning services: Food, fresh water, timber, medicines, fibres • Regulating services: Carbon sequestration, climate regulation, flood control, pollination, pest control • Cultural services: Aesthetic, spiritual, recreational value • Supporting services: Soil formation, photosynthesis, water cycling 5. Keystone species effect: • Some species (keystone species) have disproportionately large effects on ecosystem • Example: Sea otters eat sea urchins → prevent overgrazing of kelp forests • Loss of one keystone species can collapse the ecosystem 6. Trophic cascades: • Biodiversity across trophic levels maintains predator-prey balance • Loss of top predators → overabundance of herbivores → degradation of plant communities 7. Evolutionary potential: • Genetic diversity within populations allows adaptation to environmental change

Major causes of biodiversity loss — the 'Evil Quartet' (E.O. Wilson): 1. Habitat Loss and Fragmentation: • The most significant cause of biodiversity loss • Conversion of natural habitats to agriculture, urban areas, roads • Fragmentation: large continuous habitats broken into small isolated patches – Isolated populations → inbreeding, genetic drift, local extinction • Tropical deforestation: Amazon loses ~12,000–17,000 km² per year • Wetland draining, grassland conversion, coral reef destruction • Effect: Smaller habitat → fewer species (species-area relationship) 2. Over-exploitation: • Excessive harvesting of species faster than they can reproduce • Examples: – Passenger pigeon: billions → extinct (1914) due to hunting – Steller's sea cow (extinct 1768): hunted to extinction within 27 years of discovery – Overfishing: bluefin tuna, cod, shark populations collapsed – Illegal wildlife trade: tigers, rhinos, elephants (ivory, horn) – Poaching, bushmeat hunting in Africa 3. Invasive Alien Species: • Species introduced (intentionally or accidentally) outside their native range • No natural predators or competitors → outcompete native species • Examples: – Nile perch introduced into Lake Victoria → extinction of 200+ native cichlid fish species – Water hyacinth (Eichhornia crassipes) invasive in Indian water bodies – Lantana camara invading forest edges in India – Parthenium hysterophorus (carrot grass) in India – European rabbits decimating native plants in Australia – Brown tree snake eliminated many bird species in Guam 4. Co-extinctions: • When a species becomes extinct, other species that are obligately associated also go extinct • Examples: – Plant extinction → loss of specific pollinators dependent only on that plant – Fish extinction → loss of obligate parasite fish lice – Loss of Fig tree → loss of fig wasp (obligate mutualism) – Host-specific parasites extinct with their hosts Other causes: • Pollution: Water, air, soil pollution; chemical contamination (DDT, pesticides) • Climate change: Shifting habitats, coral bleaching, Arctic melting → species unable to adapt fast enough • Disease: Chytrid fungus killing amphibians globally

Conservation strategies are classified as in-situ (on-site) and ex-situ (off-site). In-situ Conservation ('in place'): • Conservation of species within their natural habitat • The most effective and preferred method • Protects entire ecosystems — all species and ecological processes protected simultaneously • Self-sustaining — species continue to adapt and evolve in natural conditions Types of in-situ conservation areas: • National Parks: Strictly protected; no human activity allowed (e.g., Jim Corbett NP, Kaziranga NP) • Wildlife Sanctuaries: Some human activities allowed; focus on specific species • Biosphere Reserves: Include core zone (strict), buffer zone, transition/manipulation zone – India has 18 biosphere reserves; 12 included in UNESCO list (e.g., Nilgiri, Sundarbans, Gulf of Mannar) • Sacred Groves: Traditional forest patches protected by local communities for religious reasons – Found in: Meghalaya (Khasi and Jaintia hills), Rajasthan, Western Ghats – Harbour endemic and rare species • Marine Protected Areas (MPAs), Ramsar Wetland Sites Ex-situ Conservation ('outside place'): • Conservation of species outside their natural habitat • Serves as backup when in-situ conservation is not possible • Used for critically endangered species, and for research and breeding programs Types of ex-situ conservation: • Zoological parks (zoos): Captive animals, breeding programs • Botanical gardens: Living plant collections • Gene banks / Seed banks: Seeds of crop plants and wild relatives stored at low temperature – National Bureau of Plant Genetic Resources (NBPGR), New Delhi — stores ~400,000 seed accessions – Svalbard Global Seed Vault (Norway) — largest seed bank • Cryopreservation: Long-term storage of gametes, embryos, cells at –196°C (liquid nitrogen) • In vitro fertilisation, embryo transfer: For endangered mammals (e.g., cheetah) • Tissue culture propagation: Plants propagated from cells; maintains genetic diversity Conclusion: In-situ and ex-situ conservation are complementary strategies. In-situ protects habitats and ecological processes; ex-situ provides insurance against extinction and material for reintroduction programs.

Important Biosphere Reserves of India: UNESCO recognised Biosphere Reserves (12 in UNESCO's Man and Biosphere programme): 1. Nilgiri — first BR in India; Western Ghats; tigers, elephants 2. Gulf of Mannar — marine BR; dugongs, sea turtles, coral reefs 3. Sundarban — Bengal tiger; largest mangrove forest 4. Nanda Devi — Uttarakhand; Himalayan BR 5. Nokrek — Meghalaya; wild relatives of citrus 6. Pachmarhi — Madhya Pradesh (Satpura) 7. Simlipal — Odisha; tigers, elephants 8. Great Nicobar — islands; saltwater crocodile, leatherback turtle 9. Agasthyamalai — Western Ghats; endemic species 10. Achanakmar-Amarkantak — Chhattisgarh/MP 11. Kanchenjunga — Sikkim; high altitude Himalayan 12. Cold Desert (Pin Valley) — Himachal Pradesh; snow leopard 13. Panna — Madhya Pradesh Important National Parks: 1. Jim Corbett NP — Uttarakhand; first NP in India (1936); tigers 2. Kaziranga NP — Assam; one-horned rhinoceros 3. Sundarbans NP — West Bengal; Bengal tiger 4. Keoladeo Ghana NP — Rajasthan; migratory birds 5. Gir Forest NP — Gujarat; Asiatic lion 6. Ranthambore NP — Rajasthan; tigers 7. Sariska NP — Rajasthan; tigers 8. Periyar NP — Kerala; tigers, elephants 9. Nagarhole (Rajiv Gandhi) NP — Karnataka 10. Valley of Flowers NP — Uttarakhand; alpine flowers Important Wildlife Sanctuaries: 1. Chilika Lake — Odisha; migratory birds 2. Vedanthangal — Tamil Nadu; waterbirds 3. Mudumalai — Tamil Nadu; tigers, elephants 4. Bhitarkanika — Odisha; saltwater crocodiles, mangroves 5. Dandeli-Anshi (Kali) — Karnataka; tigers 6. Ranganthittu — Karnataka; waterbirds

Biodiversity Hotspot: • A biogeographic region that is both a significant reservoir of biodiversity (species richness, endemism) AND is severely threatened with habitat destruction • Concept developed by Norman Myers (1988, 2000) • To qualify as a hotspot, an area must: 1. Contain at least 1,500 endemic vascular plant species (> 0.5% of world's total) 2. Have lost at least 70% of its original natural vegetation • Hotspots cover only ~2.3% of Earth's land surface but contain >50% of world's endemic plant species and ~43% of bird, mammal, reptile, and amphibian species • Originally 25 hotspots identified by Myers; now 36 identified globally Rationale: Prioritise conservation resources in areas of highest diversity and greatest threat Biodiversity Hotspots in India: 1. Western Ghats: • Mountain range along west coast of India (Gujarat to Kerala/Tamil Nadu) • Rich in endemic species: 5000+ plant species, 139 mammal species, 508 bird species, 179 amphibians (78% endemic!) • Major threats: Agriculture, urbanisation, dams, invasive species • Part of Western Ghats-Sri Lanka hotspot • Notable species: Nilgiri tahr, lion-tailed macaque, Malabar large spotted civet 2. Eastern Himalayas (Indo-Burma Hotspot includes NE India): • Includes parts of NE India (Assam, Arunachal Pradesh, Meghalaya, Manipur, etc.) • Extremely high biodiversity: rich in orchids, rhododendrons, ferns, birds, mammals • Red panda, snow leopard, clouded leopard, hoolock gibbon • Major threats: Jhum (shifting) cultivation, development, deforestation 3. Sundaland (includes Nicobar Islands): • The southern Nicobar Islands are part of the Sundaland hotspot • Leatherback sea turtle, Nicobar pigeon, saltwater crocodile Note: India is also a megadiversity country — one of 17 megadiverse countries in the world that together account for >70% of Earth's biodiversity.