Chapter 14 — Biodiversity and Conservation

Biodiversity is the number and variety of organisms found within a specified geographic region. It refers to varieties of plants, animals, and micro-organisms, the genes they contain, and the ecosystems they form — essentially the variability among living organisms within and between species and ecosystems.

The three levels are: (i) Genetic diversity — variation of genes within species; (ii) Species diversity — variety and number of species in a defined area; (iii) Ecosystem diversity — broad differences between ecosystem types and the diversity of habitats and ecological processes within each.

Biodiversity is not evenly distributed. It is consistently richer in tropical regions. As one moves toward the polar regions, populations of fewer and fewer species are found. Tropical forests alone contain about 50 per cent of the species on earth.

Species capture and store energy, produce and decompose organic materials, cycle water and nutrients, fix atmospheric gases, and help regulate the climate. A more diverse ecosystem has better chances of surviving adversities and is more productive and stable.

Major causes include rapid human population growth leading to overexploitation and deforestation, natural calamities such as floods and earthquakes, pesticides and toxic pollutants that destroy sensitive species, introduction of exotic species, and illegal poaching of animals like tigers, elephants, and rhinoceros.

The IUCN classifies threatened species into three categories: (i) Endangered — species in immediate danger of extinction (listed in the Red List); (ii) Vulnerable — species likely to become endangered if threatening factors continue; (iii) Rare — species with very small populations confined to limited areas.

The Convention on Biodiversity was signed at the Earth Summit held in Rio de Janeiro, Brazil in June 1992. India, along with 155 other nations, signed this convention. It led to steps such as preserving endangered species, protecting wild relatives of food crops, and regulating international trade in wild plants and animals.

Biodiversity hotspots are areas identified by the IUCN as most vulnerable and concentrated in species richness. They are defined according to their vegetation, since plants determine the primary productivity of an ecosystem. Madagascar, for example, has about 85 per cent of its plants and animals found nowhere else in the world.

Mega diversity centres are countries in tropical regions that possess a large number of the world's species diversity. There are 12 such countries: Mexico, Colombia, Ecuador, Peru, Brazil, Democratic Republic of Congo, Madagascar, China, India, Malaysia, Indonesia, and Australia.

India passed the Wild Life (Protection) Act, 1972, under which national parks and sanctuaries were established and biosphere reserves were declared to protect, preserve, and propagate the variety of species within natural boundaries.

Each species provides clues about how life evolved and continues to evolve. Biodiversity helps in understanding how life functions and the role of each species in sustaining ecosystems. It is also ethically important, as every species has an intrinsic right to exist.

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