Biodiversity Notes for UPSC: Ecology and Conservation
Comprehensive Biodiversity notes for UPSC Environment and Ecology. Understand genetic diversity, species distribution, hotspots, ecotones, and conservation.
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
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
Olive ridley turtle, Odisha Dugong, Tamil Nadu and Andaman and Nicobar Islands Saltwater crocodile, Sunderban delta Irrawaddy dolphin, West Bengal Horseshoe crab
Biosphere Reserves in India
Biosphere Reserve is a large protected ecosystem and landscape designated to conserve biodiversity while allowing sustainable use of natural resources and supporting the livelihood and development needs of local communities. It's a simple idea:
Conservation
Protection of landscape, ecosystems, species, and genetic diversity.
Development
promotion of sustainable economic and human development
Logistic Support
Monitoring, environmental agitation training and knowledge exchange.
Zonation of Biosphere Reserves
There are three interconnected zones
Core Zone
Most strictly protected area.
Represents the natural ecosystem.
Human activity are highly restricted.
Primarily meant for long term conservation, research and monitoring.
Buffer Zone
Surrounds the core.
In this activities compatible with conservation are permitted e.g. research, education, ecological tourism, training, sustainable resource use, etc.
Transition Zone
Outermost zone
Human settlements and economic activities are permitted
Emphasis is on sustainable development and participation of local communities.
Agriculture, forestry, fisheries and other livelihood activities can occur using sustainable practices.
Objectives of Biosphere Reserve
Protection of important habitat and landscape.
Ecosystem diversity.
Species diversity.
Genetic diversity.
Biosphere Reserves in India
Biosphere Reserves, Year
State/UT
Fauna
Nilgiri, 1986
Kerala, Tamil Nadu, Karnataka
Nilgiri tahr Lion-tailed macaque Nilgiri langur Asian elephant Tiger Gaur
Tiger Leopard Wild dog Sloth bear Gaur Four-horned antelope
Rann of Kutch, 2008
Gujarat
Wild ass Chinkara Desert fox Flamingo Indian wolf
Cold Desert, 2009
Himachal Pradesh
Snow leopard Himalayan ibex Blue sheep Tibetan wolf Himalayan marmot
Seshachalam, 2010
Andhra Pradesh, Eastern Ghats
Golden gecko Slender loris Indian giant squirrel Leopard Sambar
Panna, 2011
Madhya Pradesh
Tiger Leopard Sloth bear Chinkara Gharial Vulture
Biosphere Reserves on MAB
There are thirteen biosphere reserves in the MAB. These include:
Nilgiri
Gulf of Mannar
Sundarban
Nanda Devi
Nokrek
Similipal
Pachmarhi
Achanakmar-Amarkanta
Great Nicobar
Agasthyamalai
2001–2016 (MAB)
Khangchendzonga
2018
Panna
2011–2020
Cold Desert
2009–2035
National Parks of India
National parks find their legal basis from Section 35-38 of the Wildlife Protection Act, 1972. Its parameters are
an area can be declared as national park when the state government considered that an area because of its ecological, faunal, floral, geological or zoological association or importance need to be constituted as national park for protecting and propagating wildlife or its environment.
For it
no prescribed minimum area in the area
Selection is based on ecological and wildlife significance.
Boundaries can not ordinarily realtered expect by the resolution of the state legislature
National park receives as higher degree of protection than wildlife sanctuaries.
Activities which are Prohibited
Grazing
Livestock movement
Removal or exploitation of wildlife forest produce
Destruction or diversion of habitat
Commercial exploitation
Only such activities are done which are allowed under act
Wildlife Sanctuaries
It gets its legal basis from Section 18-33 of Wildlife Protection Act, 1972. Its parameters are
a state government may declare an area as a wildlife sanctuary when it considered that area has adequate ecological, faunal, floral, geomorphological, natural or zoological significance for the purpose of protecting wildlife or its environment. It has
No fixed minimum area prescribed in the act.
State government can alter the boundaries subject to statutory requirement.
Certain rights and regulated human activities can continue.
Important National Parks and Wildlife Sanctuaries in News 2025-26
Kuno National Park
Sheopur district, Madhya Pradesh
News for Project Cheetah
The first cheetahs arrived from Namibia in September 2022.
Cheetahs from South Africa arrived in 2023.
Nine cheetahs from Botswana arrived in February 2026.
The cheetah population in India is now 48, including 28 India-born cubs.
The expansion of Project Cheetah has recently been made to Gandhi Sagar Wildlife Sanctuary, which is adjacent to Kuno National Park. It lies in the Chambal region.
Madhav National Park
Shivpuri district, Madhya Pradesh
In March 2025, Madhav National Park became India's 58th Tiger Reserve. It is the 9th Tiger Reserve of Madhya Pradesh.
This makes the Kuno-Madhav landscape a large area for the protection and conservation of large carnivores.
Kaziranga National Park
It is in the news because of Assam floods.
Key species include the one-horned rhinoceros, tiger, Asian elephant, wild water buffalo, and swamp deer.
It has around 70% of the world's one-horned rhinoceros population.
Jaldapara National Park
It is in Alipurduar, West Bengal.
It was issued the final Eco-Sensitive Zone notification by the Centre in January 2026.
It is an important habitat for rhinoceros and elephants.
It also has important elephant corridors in North Bengal.
Kanha National Park
Kanha is known for the hard-ground barasingha.
It is in the news as an important example of species recovery through habitat management.
Dudhwa National Park
Uttar Pradesh
Key species include tiger, one-horned rhinoceros, swamp deer, and elephant.
Manas National Park
Assam
It is a Biosphere Reserve, Tiger Reserve, National Park, and UNESCO World Heritage Site.
Ranthambore National Park
Rajasthan
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