Levels of Biodiversity and Why They Matter

Prerequisites

• Biodiversity (Geography): the CBD definition, α/β/γ diversity, biogeographic zones and threats. This page builds on it.
• Ecosystems: food chains and energy flow, needed to understand keystone species
• Biology and Health: genes and cells, the basis of genetic diversity

The Hook: 20,000 Kinds of Rice in One Building

Why it matters: Prelims asks you to classify examples by level and to match terms (keystone, flagship, endemic). Mains GS-II asks why biodiversity matters and how its loss affects people, where the levels give your answer a ready structure.

The Three Levels at a Glance

The Convention on Biological Diversity (CBD), 1992, Article 2 defines biological diversity as the variability among living organisms from all sources, which includes diversity within species, between species and of ecosystems. These are the three levels.

graph TD
    B["Biodiversity (जैव विविधता)"] --> G["Genetic diversity: within a species"]
    B --> S["Species diversity: between species"]
    B --> E["Ecosystem diversity: between habitats"]
    G --> G1["Rice landraces, wild vs domestic buffalo"]
    S --> S1["Species of Kanger Valley NP"]
    E --> E1["Sal forest, grassland, river, reservoir"]

Genetic diversity: the level most often forgotten

• Genetic diversity is measured as the variation in alleles (forms of a gene) within a population. Small, isolated populations lose it through inbreeding and genetic drift.
• Example of genetic dilution: the wild buffalo in Chhattisgarh breeds with domestic buffaloes grazing in the forest. The hybrids dilute the wild gene pool. This is why “a few dozen animals” is a worse situation than the number alone suggests.
• Agro-biodiversity (कृषि जैव विविधता): traditional crop varieties (landraces) and livestock breeds. Chhattisgarh’s rice landraces and indigenous cattle and poultry breeds belong here.
• Genetic erosion: the loss of genetic variety, mostly when many local varieties are replaced by a few uniform high-yielding ones. Uniform crops are vulnerable: a single new pest or disease can hit all of them at once.

Species diversity: richness and evenness

• Species richness is the number of species in an area.
• Species evenness is how equally individuals are spread among those species. A forest with 50 species but 95% of trees of one species is rich but not even.
• Ecologists combine both in diversity indices (for example the Shannon and Simpson indices). For the exam, remember only that diversity depends on both richness and evenness.

Ecosystem diversity

• Covers the variety of ecosystems in a region and the processes inside them: nutrient cycling, succession and energy flow.
• India’s range runs from cold deserts and alpine meadows to mangroves and coral reefs. Within Chhattisgarh, the plateau forests of Bastar, the sal belt of the north and the rice plains of the centre are different ecosystem settings.
• The related measures α (within a community), β (between communities) and γ (whole region) diversity are explained in Biodiversity (Geography).

Special Roles Species Play: the Vocabulary of Conservation

Conservation money and attention are limited, so planners pick species that do the most work. These terms appear often in MCQs.

Why Conserve? The Values of Biodiversity

Ecosystem services are often grouped (as in the UN Millennium Ecosystem Assessment, 2005) into provisioning (food, water, timber), regulating (climate, floods, disease), cultural (recreation, spiritual) and supporting (soil formation, nutrient cycling).

Analysis for Mains: Conservation Must Work at All Three Levels

1. Saving species without saving genes fails. A population of a few dozen wild buffaloes may survive for a time but lose genetic health. Conservation needs enough animals and gene flow between populations, which means corridors and sometimes translocation.
2. Saving species without saving ecosystems fails. A tiger cannot survive without prey, and prey cannot survive without grassland and water. This is the logic of landscape-level conservation (for example the Guru Ghasidas-Tamor Pingla and Sanjay-Dubri landscape).
3. Agro-biodiversity is food security. Gene banks (ex-situ) and farmers who keep growing landraces (in-situ, on-farm) are both needed; see Ex-situ Conservation.
4. Biodiversity is livelihood in Chhattisgarh. Minor forest produce supports large numbers of tribal households, so loss of forest diversity is a welfare issue, not only an ecological one. See Minor Forest Produce.

Memory Tricks

Don’t Confuse

Common Mistakes

Practice

All questions below are original practice questions written in CGPSC style. They are not previous-year questions.

Level 1: Foundation

1. Variation among the thousands of rice landraces of Chhattisgarh is an example of ________ diversity.
2. A species whose protection automatically protects many others because it needs a large area is called an ________ species.
3. The four groups of ecosystem services are provisioning, regulating, cultural and ________.

Level 2: Prelims MCQs

Q1. Consider the following statements:

1. Variation among traditional varieties of rice is an example of species diversity.
2. A keystone species always has the largest population in its ecosystem.
3. The Convention on Biological Diversity defines biodiversity to include diversity within species, between species and of ecosystems.

Which of the statements given above is/are correct?

• (a) 1 and 2 only
• (b) 3 only
• (c) 2 and 3 only
• (d) 1, 2 and 3

Q2. Match List I (Term) with List II (Best example):

• (a) A-2, B-1, C-4, D-3
• (b) A-1, B-2, C-4, D-3
• (c) A-2, B-1, C-3, D-4
• (d) A-3, B-1, C-4, D-2

Q3. Which one of the following best describes “genetic erosion”?

• (a) Loss of topsoil that reduces crop genetic potential
• (b) Loss of genetic variety when many local varieties are replaced by a few uniform ones
• (c) Mutation of genes due to radiation
• (d) Transfer of genes between unrelated species by genetic engineering

Q4. Pollination of crops by wild bees is an example of which value of biodiversity?

• (a) Direct consumptive value
• (b) Option value
• (c) Indirect value (ecosystem service)
• (d) Existence value

Q5. Hybridisation of wild water buffaloes with domestic buffaloes in Chhattisgarh’s forests is a threat mainly at which level of biodiversity?

• (a) Ecosystem diversity
• (b) Genetic diversity
• (c) Species richness
• (d) Beta diversity

Level 3: Mains Answer Writing

Q1. (60 words) Distinguish between keystone, flagship and umbrella species with one Indian example each.

Q2. (150–200 words) “Conservation of species alone is not enough; genetic and ecosystem diversity must also be conserved.” Discuss with examples from Chhattisgarh.

Quick Revision Table

Key Takeaways

What’s Next

• Biodiversity Hotspots and Megadiversity: where biodiversity is richest and most threatened
• In-situ Conservation: protecting species where they live
• Agricultural Science: crop varieties, breeding and seeds
• Forests and Wildlife of Chhattisgarh: the state’s forests and protected areas