Conserving Biodiversity: Quick Revision

A brief note on Conserving Biodiversity. Read it before a test. Try each question at the end before you open its answer.

In situ and ex situ

• In situ: on site, in the habitat. It is the best way.
• Ex situ: off site. Zoological parks, botanical gardens, wildlife safari parks, seed banks, cryopreservation of gametes, tissue culture.

In situ methods

• Hotspots: very high species richness and high endemism. 25 first, 34 in NCERT. Less than 2 per cent of the land. Almost 30 per cent fewer extinctions. Western Ghats and Sri Lanka, Indo-Burma, Himalaya.
• India (NCERT): 14 biosphere reserves, 90 national parks, 448 wildlife sanctuaries.
• Zones of a biosphere reserve: core with no human activity, buffer with limited use, transition with farms and villages.
• Sacred groves: Khasi and Jaintia Hills, Aravalli Hills, Western Ghats, Sarguja, Chanda and Bastar.

Red Data Book

• IUCN Red List categories, from the highest risk: Extinct, Extinct in the Wild, Critically Endangered, Endangered, Vulnerable, Near Threatened, Least Concern.
• Threatened: Critically Endangered, Endangered and Vulnerable.
• International (not in the NEET syllabus): Earth Summit at Rio de Janeiro, 1992. Johannesburg, 2002, 190 countries, target year 2010.

A worked example

A model region is expected to lose 400 species. Protection could cut the loss by almost 30 per cent. How many species are saved?

1. Take 30 per cent of the loss.
2. $0.30 \times 400 = 120$ species.

Practice with new numbers

A program to try

The program works out the hotspot area and the extinctions avoided.

Mistakes to avoid

• Calling a zoo or a seed bank in situ. They are ex situ.
• Mixing up the two figures of the hotspots. 2 per cent is the land. 30 per cent is the cut in the extinctions.
• Putting Near Threatened among the threatened.
• Mixing up the two summits. Rio de Janeiro was 1992. Johannesburg was 2002.

Check yourself

1. What are the two features of a hotspot?

2. Name three ex situ methods.

3. Which categories of the Red List are called threatened?

4. What is found in the core zone of a biosphere reserve?

Sources

• NCERT (2023). Biology, Textbook for Class XII, chapter 13.
• IUCN (2012). IUCN Red List Categories and Criteria, version 3.1, second edition.
• OpenStax Biology 2e (2018), chapter 47, Conservation Biology and Biodiversity.