Introduction
Biodiversity — the variety of life on Earth at all levels, from genes to ecosystems — forms the biological foundation upon which human civilization is built. For the OPSC aspirant, this subtopic sits at the intersection of physical geography, environmental science, and sustainable development policy. It is not merely a static list of species and protected areas; it is a dynamic field that examines how life distributes itself across the planet, why certain regions harbour extraordinary concentrations of unique species, and how human activity threatens or preserves this natural heritage.
The official OPSC syllabus explicitly lists "Biodiversity — hotspots, conservation, endemic species" as a core component of the Geography paper. However, a careful analysis of the 11 previous year questions (PYQs) provided reveals a fascinating pattern: OPSC has tested this subtopic in a layered manner. Some questions directly address biodiversity concepts — such as the statement-based question on Biosphere Reserves in OPSC 2025 — while others approach biodiversity tangentially through related themes like climatic classification (OPSC 2022), ocean currents (OPSC 2019), demographic transitions and subsistence farming (OPSC 2020), and even historical cultural absorption (OPSC 2024). This tells us that OPSC expects candidates to understand biodiversity not as an isolated topic but as an integrated dimension of geography that connects climate, vegetation, human settlement patterns, and conservation policy.
The difficulty level of these questions ranges from straightforward factual recall (e.g., highest peak of the Appalachians in OPSC 2021) to analytical matching (Köppen's classification in OPSC 2022) to conceptual understanding (denudation controlled by plants in OPSC 2019). The 2025 question on Biosphere Reserves represents the most direct engagement with the core syllabus point, requiring nuanced knowledge of India's conservation network. This suggests that future examinations will likely deepen this direct testing while maintaining the integrative approach.
In this chapter, you will learn: what biodiversity means at genetic, species, and ecosystem levels; why certain regions qualify as biodiversity hotspots and how many exist in India; the distinction between endemic, exotic, and keystone species; the legal and institutional framework for conservation in India including the Wildlife Protection Act of 1972, Project Tiger, and Biosphere Reserves; the specific biodiversity wealth of Odisha including its Eastern Ghats, coastal ecosystems, and wildlife sanctuaries; and how to connect these concepts to broader geographical themes like climate, soils, and agriculture. By the end, you will be equipped to answer not just the questions that have been asked, but those that are likely to appear in future OPSC examinations.
Core Concepts & Foundations
Before diving into the specifics of hotspots and conservation strategies, we must establish a rigorous conceptual foundation. Biodiversity is a term that is often used loosely in public discourse, but for the OPSC examination, precision is essential.
Biodiversity: The variety of living organisms from all sources, including terrestrial, marine, and other aquatic ecosystems, and the ecological complexes of which they are part. It encompasses diversity within species (genetic diversity), between species (species diversity), and of ecosystems (ecosystem diversity). The Convention on Biological Diversity (CBD) of 1992 formally defined biodiversity as "the variability among living organisms from all sources."
Genetic Diversity: The variation of genes within a species. This is the raw material for evolution and adaptation. For example, the thousands of rice varieties in India — from the aromatic Basmati to the flood-tolerant Swarna — represent genetic diversity within a single crop species. Loss of genetic diversity reduces a species' ability to adapt to environmental changes.
Species Diversity: The variety of species within a habitat or region. This is the most commonly measured level of biodiversity, often quantified through species richness (the number of species) and species evenness (the relative abundance of each species). India is home to approximately 8% of the world's recorded species despite having only 2.4% of the global land area.
Ecosystem Diversity: The variety of habitats, communities, and ecological processes within a geographic area. India's ecosystem diversity ranges from the cold deserts of Ladakh to the tropical rainforests of the Western Ghats, from the coral reefs of the Andaman and Nicobar Islands to the mangroves of the Sundarbans.
Endemic Species: Species that are native to a particular geographic area and are found nowhere else on Earth. Endemism is a key criterion for identifying biodiversity hotspots. For example, the Lion-tailed Macaque is endemic to the Western Ghats, and the Gharial is endemic to the Indian subcontinent's river systems.
Biodiversity Hotspot: A biogeographic region that is both a significant reservoir of biodiversity and is threatened with destruction. To qualify as a hotspot, a region must contain at least 1,500 species of vascular plants as endemics (0.5% of the world's total) and must have lost at least 70% of its original primary vegetation. The concept was developed by Norman Myers in 1988 and later adopted by Conservation International.
Keystone Species: A species whose impact on its ecosystem is disproportionately large relative to its abundance. The removal of a keystone species can cause a cascade of extinctions. The Tiger is a classic keystone species — as an apex predator, it regulates prey populations, which in turn affects vegetation structure.
Flagship Species: A charismatic species that serves as a symbol for conservation efforts. The Bengal Tiger is India's flagship species, and conservation efforts for the tiger have protected entire ecosystems that benefit countless other species.
Umbrella Species: A species whose conservation confers protection to a large number of other species sharing its habitat. The Asian Elephant is an umbrella species — protecting elephant corridors protects the entire forest ecosystem.
Ex-situ Conservation: The conservation of components of biological diversity outside their natural habitats. Examples include zoos, botanical gardens, gene banks, and seed banks. The National Bureau of Plant Genetic Resources (NBPGR) in New Delhi maintains India's ex-situ collection of crop genetic resources.
In-situ Conservation: The conservation of ecosystems and natural habitats and the maintenance and recovery of viable populations of species in their natural surroundings. This is achieved through a network of protected areas including National Parks, Wildlife Sanctuaries, Conservation Reserves, Community Reserves, and Biosphere Reserves.
Biosphere Reserve: A large protected area designated under UNESCO's Man and Biosphere (MAB) Programme that aims to reconcile conservation of biodiversity with its sustainable use. Biosphere Reserves have three zones: a core zone (strictly protected), a buffer zone (limited human activity), and a transition zone (sustainable resource use). India has 18 Biosphere Reserves as of 2024.
Endangered Species: A species that is at high risk of extinction in the wild. The International Union for Conservation of Nature (IUCN) Red List categorizes species into nine groups: Extinct, Extinct in the Wild, Critically Endangered, Endangered, Vulnerable, Near Threatened, Least Concern, Data Deficient, and Not Evaluated.
Critically Endangered Species: A species facing an extremely high risk of extinction in the wild. India has several critically endangered species including the Great Indian Bustard, Gharial, Pygmy Hog, and Javan Rhinoceros (now extinct in India).
Now, let us understand how these concepts interconnect. Biodiversity is not a static inventory; it is a dynamic system shaped by evolutionary processes, geological history, climate, and increasingly, human activity. The theory of island biogeography by Robert MacArthur and E.O. Wilson explains why certain regions have higher biodiversity: larger areas and closer proximity to source populations support more species. This theory has profound implications for conservation — it tells us that fragmented habitats (like forest patches surrounded by agriculture) will lose species over time, a process called faunal relaxation.
India's high biodiversity is a product of its unique geography. The country spans multiple biogeographic zones: the Trans-Himalayan cold deserts, the Himalayan mountains, the Desert of Rajasthan, the Semi-Arid zone, the Western Ghats rainforests, the Deccan Peninsula forests, the Gangetic Plains, the North-East region, the Coastal areas, and the Islands. Each zone has distinct species assemblages shaped by climate, soil, and geological history.
The concept of endemism is particularly important for OPSC. Endemic species are often concentrated in areas that have been geographically isolated for long periods — islands, mountain ranges, and peninsulas. India's Western Ghats and Eastern Himalayas are centres of endemism because they served as refugia during past climatic changes. The Eastern Ghats of Odisha, while less studied than the Western Ghats, also harbour significant endemism, particularly in the Mahendragiri and Similipal regions.