Biodiversity conservation: in situ, ex situ and hotspots
Biodiversity is conserved in situ (in natural habitats, such as hotspots and protected areas) and ex situ (outside them, such as zoos, seed banks and cryopreservation).
In situ vs ex situ conservation
Conserving a whole forest in situ saves not just the tiger but every species in it. Ex situ is the back-up for species that cannot survive in the wild for now.
Biodiversity hotspots
To save the most species at the least cost, conservationists picked out biodiversity hotspots: regions with very high species richness and a high degree of endemism. Endemic species are those confined to one region and found nowhere else. At first 25 hotspots were identified; nine more were added, making 34 in your textbook. Three of them cover India's richest regions: Western Ghats and Sri Lanka, Indo-Burma and Himalaya. (Extra reading, not in your textbook: later lists count 36 hotspots, and some add Sundaland, which includes the Nicobar Islands, as a fourth touching India.) All hotspots together cover less than 2 per cent of Earth's land, yet they hold a very large share of its species. Strict protection of hotspots could reduce the ongoing mass extinctions by almost 30 per cent.
Ex situ conservation methods
- Zoological parks, botanical gardens and wildlife safari parks: many animals that are extinct in the wild survive here.
- Captive breeding: threatened animals are bred in captivity and, where possible, released back into the wild.
- Cryopreservation: gametes of threatened species are stored in a viable and fertile state for long periods, usually in liquid nitrogen at −196 °C.
- In vitro fertilisation: stored eggs can be fertilised in the laboratory.
- Tissue culture: plants can be multiplied from small pieces of tissue.
- Seed banks: seeds of different genetic strains of commercially important plants are kept alive for long periods.
International efforts
Biodiversity knows no political borders, so conservation is a shared job. The historic Convention on Biological Diversity at the Earth Summit in Rio de Janeiro (1992) called on all nations to conserve biodiversity and use its benefits sustainably. A follow-up meeting was the World Summit on Sustainable Development in Johannesburg, South Africa (2002). There, 190 countries pledged a significant reduction in the rate of biodiversity loss by 2010.
The National Bureau of Plant Genetic Resources in New Delhi keeps the seeds of thousands of crop varieties in its gene bank, an ex situ store for India's farmers. The Western Ghats, one of India's hotspots, feed rivers that water much of South India.
2 marks: “Distinguish between in situ and ex situ conservation with one example each.” In situ: conservation in the natural habitat, e.g. national parks, biosphere reserves, sacred groves. Ex situ: conservation outside the natural habitat, e.g. zoos, botanical gardens, seed banks, cryopreservation.
2 marks: “What are biodiversity hotspots? Name the hotspots that cover India's biodiversity-rich regions.” Regions with very high species richness and a high degree of endemism. Western Ghats and Sri Lanka, Indo-Burma, and Himalaya.
5 marks: “Explain how biodiversity is conserved. Describe in situ and ex situ methods with examples.” In situ: hotspots (34 in the textbook, less than 2% of land, could cut extinctions by almost 30%); protected areas; sacred groves. Ex situ: zoos, botanical gardens, safari parks; cryopreservation of gametes; IVF; tissue culture; seed banks. International: Rio 1992, Johannesburg 2002.
In situ: in the home. Ex situ: exit the home, into zoos, gardens and seed banks.