Biodiversity and its Conservation

The One Thing

Biodiversity encompasses variation at genetic, species, and ecosystem levels, and it supports ecosystem functioning and human well-being. Its conservation requires protection of habitats and ecological processes, sustainable resource use, legal regulation, community participation, and both in situ and ex situ methods.

Reactions, Processes and Experiments

Key Terms

• Biodiversity: The variety and variability of living organisms and the ecological complexes in which they occur.
• Genetic diversity: Variation in genes within a species or population, helping organisms adapt to changing conditions.
• Species diversity: The variety of species in a region, including both the number of species and their relative abundance.
• Ecosystem diversity: The variety of habitats, biological communities, and ecological processes in a geographical area.
• Species richness: The total number of species present in a particular area.
• Species evenness: The relative abundance of different species in a community.
• Latitudinal gradient: The general pattern in which species diversity increases from the poles towards the equator.
• Species-area relationship: The relationship in which the number of species increases with the area explored, represented by S = C A^Z.
• Species-area curve: A graph showing the increase in the number of species as the area of a habitat increases.
• Endemic species: A species naturally found only in a particular geographical region.
• Biodiversity hotspot: A region with exceptionally high species richness and endemism that is under significant threat.
• Keystone species: A species whose effect on ecosystem structure and functioning is much greater than expected from its abundance.
• Ecosystem services: Benefits provided by ecosystems, such as pollination, climate regulation, soil formation, nutrient cycling, and water purification.
• Extinction: The permanent disappearance of a species from Earth.
• Co-extinction: The extinction of one species following the disappearance of another species with which it is closely associated.
• In situ conservation: Conservation of species within their natural habitats, such as in national parks, wildlife sanctuaries, and biosphere reserves.
• Ex situ conservation: Conservation of species outside their natural habitats, such as in zoos, botanical gardens, seed banks, gene banks, and cryopreservation facilities.
• National park: A protected area managed mainly to conserve ecosystems, wildlife, and natural features, with human activities strictly regulated.
• Wildlife sanctuary: A protected area established mainly for the protection of wild animals, where some regulated human activities may be permitted.
• Biosphere reserve: A large protected area designed to conserve biodiversity while allowing compatible research, education, and sustainable development.
• Red Data Book: A record of threatened species and information about their conservation status.
• IUCN Red List: A global system that assesses the extinction risk of species using categories such as Critically Endangered, Endangered, Vulnerable, and Least Concern.
• Evil quartet: The four major forms of biodiversity loss consisting of habitat loss and fragmentation, overexploitation, alien species invasions, and co-extinctions.
• Megadiverse country: A country containing exceptionally high diversity of ecosystems, species, and genetic resources; India is recognised as one.
• Biodiversity hotspot in India: The Himalaya, Indo-Burma region, Western Ghats-Sri Lanka region, and Sundaland, represented in India by the Nicobar Islands.

Easily Confused

• Species richness vs species evenness: Species richness is the total number of species; species evenness is the relative abundance of those species.
• In situ vs ex situ conservation: In situ conservation protects species in their natural habitats, whereas ex situ conservation maintains them outside those habitats.
• National park vs wildlife sanctuary: National parks generally impose stricter regulation of human activities, whereas wildlife sanctuaries may permit some regulated activities.
• National park vs biosphere reserve: A national park primarily protects ecosystems, wildlife, and natural features, whereas a biosphere reserve combines biodiversity conservation with compatible research, education, and sustainable development.
• Extinction vs co-extinction: Extinction is the disappearance of a species; co-extinction is the disappearance of one species following the loss of a closely associated species.
• Species-area relationship vs species-area curve: The species-area relationship is expressed by S = C A^Z, while the species-area curve is the graph representing that relationship.
• Red Data Book vs IUCN Red List: The Red Data Book records threatened species and conservation information, whereas the IUCN Red List assesses extinction risk using defined categories.
• Endemic species vs biodiversity hotspot: An endemic species is restricted to one geographical region, whereas a biodiversity hotspot is a threatened region with high species richness and endemism.
• Habitat loss vs overexploitation: Habitat loss removes or fragments living space, whereas overexploitation removes organisms faster than they can reproduce.
• Conservation of habitats vs conservation of isolated species: Habitat protection preserves communities, ecological interactions, and evolutionary processes, whereas isolated-species protection does not necessarily preserve these wider systems.

What Gets Asked

• Questions may require the three levels of biodiversity—genetic diversity, species diversity, and ecosystem diversity—to be identified and distinguished. A common error is to confuse species richness, which measures the number of species, with species evenness, which measures their relative abundance.
• Questions may require use of the species-area equations S = C A^Z and log S = log C + Z log A, including identification of S, A, C, and Z. The typical values of Z must be distinguished: about 0.1 to 0.2 for small areas and approximately 0.6 to 1.2 for very large areas such as continents.
• Questions may ask why tropical regions have greater species richness. The required factors are long-term climatic stability, greater solar energy, higher productivity, and more varied habitats; merely stating that the tropics are warmer is incomplete.
• Questions may ask for the major causes of biodiversity loss or the “evil quartet.” The complete list is habitat loss and fragmentation, overexploitation, alien species invasions, and co-extinctions; pollution and climate change are also major threats but are not components of the named quartet.
• Questions may require examples of invasive species in India. The named examples are water hyacinth, Lantana camara, and Parthenium hysterophorus; these should not be replaced by unspecified examples.
• Questions may compare conservation approaches or protected areas. Answers should distinguish in situ from ex situ conservation and national parks from wildlife sanctuaries and biosphere reserves, including the different degrees and purposes of regulated human activity.
• Questions may ask about conservation legislation and international agreements. The relevant details are the Wildlife Protection Act of India (1972), CITES (1973), and the Convention on Biological Diversity (1992), including their respective purposes.