Ecology, Biodiversity and Conservation

Ecology basics

• An ecosystem has biotic parts (producers, consumers, decomposers) and abiotic parts (light, water, soil, temperature).
• Food chain and food web: for example, grass → deer → tiger. Food webs are more stable than single chains.
• Energy flow: energy flows one way. Only about 10% passes to each higher trophic level (Lindeman's law). The pyramid of energy is always upright. The pyramid of biomass is inverted in aquatic systems.
• Biogeochemical cycles: carbon, nitrogen (fixation by Rhizobium, and by lightning), phosphorus (a sedimentary cycle) and water.
• Ecological succession: primary succession (on bare rock, starting with lichens) and secondary succession, ending in a climax community.
• Biomagnification: toxins such as DDT and mercury concentrate up the food chain. Eutrophication happens when excess nutrients cause algal blooms.
• Key terms:
  • Ecotone: a transition zone, often rich in species (the "edge effect").
  • Niche: a species' role.
  • Keystone species: for example, the tiger and the fig tree.
  • Flagship species.
  • Indicator species: for example, lichens show air quality.

Biodiversity

• Three levels: genetic, species and ecosystem diversity.
• India has about 2.4% of the world's land but 7–8% of recorded species. It is one of the 17 megadiverse countries.
• Hotspots (Norman Myers, 1988; Conservation International): 36 worldwide. India has parts of 4: the Himalaya, Indo-Burma, the Western Ghats–Sri Lanka and Sundaland (the Nicobar Islands).
• Threats ("HIPPO"): Habitat loss, Invasive species (e.g. Lantana, water hyacinth), Pollution, human Population and Overexploitation, plus climate change.

Conservation

In situ (in the natural habitat)

Type	Law / basis	Notes
National parks	WPA 1972	No human activity; 100+ in India
Wildlife sanctuaries	WPA 1972	Some activities allowed; 550+
Conservation and community reserves	WPA amendment 2002	Community participation
Tiger reserves	Project Tiger 1973; NTCA (2006)	58 reserves (2025)
Elephant reserves	Project Elephant 1992	33
Biosphere reserves	UNESCO MAB (1971)	18 in India; 13 in the world network (Nilgiri was first, 2000)
Ramsar wetlands	Ramsar Convention 1971 (Iran)	India has 90+ sites (2025); Tamil Nadu has the most
Sacred groves	Community	Sarna groves in Jharkhand; devrai in Maharashtra

Ex situ (outside the natural habitat): zoos, botanical gardens, seed and gene banks (NBPGR, New Delhi) and cryopreservation.

Bihar and Jharkhand protected areas

• Bihar:
  • Valmiki Tiger Reserve (West Champaran);
  • Vikramshila Gangetic Dolphin Sanctuary (Bhagalpur);
  • Bhimbandh (Munger), Kaimur, Rajgir and Gautam Buddha (Gaya) sanctuaries;
  • Kanwar Lake (Ramsar, 2020);
  • the Nagi and Nakti dams (Ramsar, 2024).
• Jharkhand:
  • Betla National Park and Palamau Tiger Reserve (one of the original nine in 1973);
  • Dalma (elephants);
  • Hazaribagh, Koderma, Mahuadanr (wolves), Topchanchi, Udhwa Lake bird sanctuary (Ramsar, 2025) and Parasnath.

Laws and policies

• Wildlife (Protection) Act 1972: the 2022 amendment reduced the Schedules to four and gave effect to CITES.
• Forest (Conservation) Act 1980: the 2023 amendment renamed it Van (Sanrakshan Evam Samvardhan) Adhiniyam and has been controversial over the definition of "forest".
• Environment (Protection) Act 1986: an umbrella law passed after Bhopal.
• Biological Diversity Act 2002, amended in 2023: the National Biodiversity Authority (Chennai), State Biodiversity Boards and People's Biodiversity Registers.
• Forest Rights Act 2006.
• Compensatory afforestation: the CAMPA Act 2016.

IUCN Red List categories: Least Concern, Near Threatened, Vulnerable, Endangered, Critically Endangered, Extinct in the Wild, Extinct.

Critically endangered in India: the Great Indian Bustard, gharial, pygmy hog and Malabar large-spotted civet. The Gangetic dolphin is classed as Endangered.

Species projects

• Project Tiger (1973). The 2022 estimate was 3,682 tigers, about 75% of the world's wild tigers.
• Project Elephant (1992).
• Project Cheetah (2022, at Kuno, MP), which brought cheetahs from Namibia and South Africa.
• Project Dolphin (2020).
• Project Snow Leopard.
• The Great Indian Bustard recovery programme.
• Vulture action plans: diclofenac is banned for veterinary use.

Community conservation:

• Chipko (1973, Uttarakhand; Gaura Devi and Sunderlal Bahuguna);
• Appiko (Karnataka);
• the Bishnois (Khejarli, 1730, Amrita Devi);
• Joint Forest Management (1990);
• Silent Valley.

Environmental Impact Assessment

• EIA was made mandatory under the EIA Notification 1994, replaced by the 2006 notification. The categories are A (Centre) and B (state).
• Steps: screening, scoping, public consultation, appraisal.
• Criticisms:
  • post-facto (ex post facto) clearances, on which the Supreme Court's rulings shifted during 2025, so check the current position;
  • poor quality of consultants' reports;
  • weak public hearings.
• The National Green Tribunal (2010) handles environmental disputes.

Exam tip: Prelims asks for protected areas by state, so make one map per state. BPSC and JPSC almost always ask about Valmiki, Vikramshila, Kanwar Lake, Betla/Palamau and Dalma.