Biodiversity
Biodiversity is the variability among living organisms from all sources including diversity within species, between species and of the ecosystems.
Why is biodiversity high in some regions?
- Warm Climate
- Tropical rainforest have high biodiversity.
- High solar energy rainfall
- Habitat heterogeneity e.g. in Himalayas tropical temperate and alpine all types of ecosystem are found.
- Environmental stability e.g. Amazon and Congo Basin
- Long evolutionary history e.g. Western Ghats
- Geographic isolation e.g. Madagascar
- Presence of number of ecotones
- Ecotones are transitional zones between ecosystems.
- High primary productivity
- Higher plant biomass support longer food web.
- Habitat complexity e.g. multi-layered tropical rainforest.
Genetic Diversity
Genetic diversity means variation in genes among individuals and population of same species. It produces differences in traits such as disease resistant, drought tolerance, salinity tolerance, colour, size, yield and adaptability e.g. a variety of rice could be drought resistant, flood resistant, salt tolerant, etc.
Causes of Genetic Diversity
- Mutation
- Random changes in DNA create new genetic variants.
- Recombination
- During sexual reproduction genes are reshuffled producing new combinations
- Gene Flow
- Movement of genes between population through migration and inter-breeding
- Natural selection
- Geographic isolation
- It reduces gene flow
In 2025, India's Department of Biotechnology reported the development of the Indian Chickpea Small panArray (indiCA), based on a chickpea pangenome genotyping approach. It attempts to capture the genetic repertoire across multiple varieties of a species rather than relying on only one reference genome.
Species Diversity
Species diversity refers to the variety of species present in a particular ecosystem it considered both aspects species richness i.e. number of species and species evenness i.e. relative abundance of different species. Its causes are
- Allopatric
- Physical Barrier
- Darwin Finch Birds
- Peripatric
- Peripheral population become isolated
- Parapatric
- Population remains geographically continuous but experience different environmental conditions e.g. grasses in mining areas.
- Sympatric
- New species arrives in same geographical area due to isolation
Ecosystem Diversity
Ecosystem diversity is the variety of different ecosystems, habitat and associated ecological process within a geographical area. e.g. The Himalayas contain forest, Alpine Meadows, rivers, wetlands and that's why it has high biodiversity
Measurement of Ecosystem Diversity
- Alpha Diversity
- Diversity within habitat/ecosystem.
- e.g. Sundarbans ecosystem has 40 species of plant and animals
- Beta Diversity
- It is diversity between two or more ecosystems
- e.g. forest ecosystem have species a, b, c and d and grassland ecosystem has c, d and e. The difference in the species composition between the forest and grassland represents beta diversity.
- Gamma Diversity
- Total species diversity across a large geographical area containing multiple ecosystem
- e.g. Western Ghats contain evergreen forest ecosystem, moist deciduous ecosystem, shola forest ecosystem, grassland ecosystem, wetland ecosystem, etc.
Importance of Biodiversity
- Ecosystem Stability
- Greater biodiversity creates interconnected food webs and make the system stable.
- India's seventh National Biodiversity Report 2026 highlights conservation of forest, wetland and species as central to ecosystem health.
- Provisioning Services
- Biodiversity provide food fibre, timber, medicines, genetic resources, etc.
- National Biodiversity Report 2026 has mention that India's forest ecosystem services creates about 2.5 trillion dollar annually
- Genetic Resources and Food Security
- e.g. chickpea pangenome work
- Pollination
- Diversity of bees, butterfly and pollinators.
- Pest and Diseases regulation
- Climate regulation
- As per Biodiversity Report 2026 India's forest carbon stock is 7285.5 million tons.
- Disaster risk reduction
- e.g. mangroves protect from cyclone
- Water security
- e.g. scared grooves and scared lakes
- Soil fertility and nutrient cycling
- Economic and livelihood value
- Medical and pharmaceutical value
- Cultural and spiritual value
- Scientific and educational value
- Tourism and recreation
- Evolution resilience
India's Seventh National Report to CBD 2026 has highlighted that 21.4 million hac land is under restoration
Indian forest estimated to provide 2.5 trillion dollar per annum in ecosystem service.
Devarakadus, Kodagu - It is scared community forest has illustrated the linkages between biodiversity, indigenous traditions and water security.
Threats to Biodiversity
- Natural disaster
- Assam Flood
- Periodically affect Kaziranga Wildlife
- Drought
- African savanna
- Wildfire
- Forest fire in Australia, Western Himalaya
- Natural climatic fluctuations
- These are past climatic changes which contribute to a major shift in vegetation.
- Natural disease outbreaks
- Assam Flood
- Man-made factor
- Habitat loss and degradation
- India's 7th CBD report mention that about 29.77% of India's land is undergoing degradation.
- Habitat fragmentation
- Railways, highways in the Himalayas, northeast, etc.
- Over exploitation
- Overfishing or illegal trade of pangolins
- Invasive alien species
- Water hyacinth, Lantana camara Porosophus julifera, Partenium, etc.
- India's 2026 Biodiversity Assessment reported expansion of invasive species, including a substantial increase of Cromolyn odorata, in tiger range states.
- NBA, that is, National Biodiversity Authority, constituted an expert committee on invasive alien species in March 2026 following an NGT direction.
- Pollution
- Like plastic, chemical pesticides
- Climate change
- Global warming. Example: chlorination.
- Ocean acidification
- The 2026 State of India's Environment Assessment identified ocean acidification as a measure of planetary boundary condition.
- Human-wildlife conflict
- Unsustainable agriculture monoculture
- Infrastructure development projects which affect and elephant and tiger corridors
- Poaching and illegal wildlife trade example: rhino horn, tiger parts, pangolin scales, exotic reptiles.
- Unsustainable tourism
- Habitat loss and degradation