Chapter 13: Biodiversity and Conservation

Introduction

Overview

• Earth hosts vast life diversity: 20,000+ ant species, 300,000+ beetles, 28,000 fishes, 20,000 orchids.

Memory Aids

• Remember: "Millions of species, millions of forms".

Quick Checkpoints

• What is the scale of species diversity on Earth?

Biodiversity

Definition and Levels

• Biodiversity: Variety of ecosystems, species, biotypes, and genes with interactions.
• Term coined by Walter G. Rosen (1985), popularised by Edward Wilson (1992).
• Varies by environment and species tolerance.
• Over 1.5 million species described; many more undiscovered, especially in tropics.
• Three levels: Genetic diversity, Species diversity, Ecological diversity.

Memory Aids

• Genetic = genes variation; Species = number & variety; Ecological = ecosystem variety.
• Alpha = within habitat; Beta = between habitats; Gamma = across regions.

Quick Checkpoints

• What are the three hierarchical levels of biodiversity?
• Who coined and popularised the term biodiversity?

Global Species Diversity

Key Facts

• Estimated 7 million species globally (Robert May).
• Animals: 70% of species; Plants: 22% including algae, fungi, bryophytes, gymnosperms, angiosperms.
• Insects are 70% of animal species; 7 out of 10 animals are insects.
• Fungi species outnumber combined fishes, amphibians, reptiles, mammals.

Memory Aids

• Remember: "7 million species, 70% animals, 70% insects among animals".

Quick Checkpoints

• What percentage of global species are animals?
• Which animal group is most species-rich?

Biodiversity in India

Highlights

• India has 2.4% of world land but 8.1% of global species diversity.
• One of 12 mega-diversity countries.
• Divided into 10 biogeographical regions including Himalayas, Western Ghats, Deccan Peninsula, etc.
• Recorded: 45,000 plant species, twice as many animal species.
• Estimated undiscovered: 100,000+ plants, 300,000+ animals.
• Endemic species confined to regions, e.g., Western Ghats amphibians.

Memory Aids

• India: "Small land, big diversity".

Quick Checkpoints

• What percent of global species diversity does India hold?
• What are endemic species?

Patterns of Biodiversity

Latitudinal Gradients

• Species diversity decreases from equator to poles.
• Tropics (23.5°N to 23.5°S) have highest species richness.
• Examples: Colombia (1400 bird species), New York (105), Greenland (56).
• Amazon rainforest: richest biodiversity with 40,000+ plants, 125,000+ invertebrates.
• Reasons for tropical richness: long speciation time, stable environment, more solar energy.

Species Area Relationship

• Species richness increases with area but up to a limit.
• Relationship follows log scale: log S = log C + Z log A.
• Z value usually 0.1-0.2; higher for continents.

Memory Aids

• Latitudinal: "More species near equator".
• Species-area: "Bigger area, more species".

Quick Checkpoints

• How does species diversity change with latitude?
• What is the species-area relationship?

Importance of Species Diversity

Benefits to Ecosystem

• Ecological stability: Diverse ecosystems resist stress and alien species invasion.
• Higher productivity in ecosystems with more biodiversity.
• Maintains ecosystem health via checks, feedbacks, keystone species.
• Rivet popper hypothesis: Loss of species weakens ecosystem like rivets in a plane.

Memory Aids

• Think: "More species = stronger ecosystem".

Quick Checkpoints

• Why is species diversity important for ecosystem stability?
• Explain the rivet popper hypothesis.

Loss of Biodiversity

Causes and Effects

• Rapid decline due to human activities.
• IUCN Red List (2004): 784 species extinct in last 500 years.
• 15,500+ species currently threatened worldwide.
• Extinction rates 100-1000 times faster than pre-human times.
• Five mass extinctions in history; current trend may wipe out half species in 100 years.

Memory Aids

• Extinction types: Natural (slow), Mass (catastrophic), Anthropogenic (human-caused).

Quick Checkpoints

• What are the types of extinction?
• How fast is current extinction compared to natural rates?

Causes of Biodiversity Loss

Main Causes

• "Evil Quartet": Habitat loss & fragmentation, over-exploitation, alien species invasion, co-extinction.
• Habitat loss: Deforestation, wetland filling, urbanization reduce species habitats.
• Fragmentation disrupts species interactions, affects large-territory animals.
• Over-exploitation: Excessive hunting/fishing reduces populations, risks extinction.
• Alien species: Non-native invasives outcompete natives, e.g., Water hyacinth, Nile Perch.
• Co-extinction: Extinction of one species causes dependent species to vanish.

Other Causes

• Disturbance & degradation: Fires, pests, human clearing.
• Pollution: Pesticides cause biomagnification; heavy metals and oil spills harm species.
• Intensive agriculture: Habitat loss and reduced genetic diversity.
• Forestry: Pure tree plantations reduce forest biodiversity.

Memory Aids

• Remember "Evil Quartet" for main causes.

Quick Checkpoints

• What are the main causes of biodiversity loss?
• How do alien species affect native biodiversity?

Red List Categories

Extinction Risk Levels

• Extinct: Species completely gone, e.g., Dodo.
• Critically Endangered: Very high risk, e.g., Pigmy Hog.
• Endangered: High risk, e.g., Lion-tailed Macaque.
• Vulnerable: Population declining, risk in medium term, e.g., Clouded Leopard.
• Extinct in Wild: Absent in natural habitat.
• Lower Risk: Threatened but stable.
• Data Deficient: Insufficient data for assessment.
• Rare Species: Naturally small populations, always at risk.
• Not Evaluated: No assessment done.
• Indeterminate: Risk present but cause unknown.

Memory Aids

• Order: Extinct < Critically Endangered < Endangered < Vulnerable < Lower Risk.

Quick Checkpoints

• What does 'Critically Endangered' mean?
• Which category means species is extinct in the wild?

Biodiversity Conservation

Concept and Importance

• Protection and scientific management of biodiversity to maintain optimum levels.
• Ensures sustainable benefits for present and future generations.
• Reasons to conserve biodiversity:
  • Narrowly utilitarian: Direct economic benefits like food, medicine, industrial products.
  • Broadly utilitarian: Ecosystem services like oxygen production, pollination, aesthetic value.
  • Ethical: Every species has intrinsic value beyond economic use.
• Red List purpose:
  • Raise awareness of biodiversity threats.
  • Provide global index of biodiversity decline.
  • Identify species at high risk of extinction.
  • Set conservation priorities and actions.
  • Inform about international agreements like CBD and CITES.

Memory Aids

• "Narrow" = direct benefits (food, medicine).
• "Broad" = ecosystem services (oxygen, pollination).
• Ethical = intrinsic value of all species.
• Red List = awareness + action + global index.

Quick Checkpoints

• What are the three main reasons to conserve biodiversity?
• What is the purpose of the Red List?
• How does biodiversity benefit humans economically?

Conservation Strategies

Types and Methods

• Two main types: In-situ and Ex-situ conservation.
• In-situ: Protect species in natural habitats (hotspots, protected areas).
• Ex-situ: Protect species outside natural habitats (seed banks, gene banks, botanical gardens, zoos).

Memory Aids

• In-situ = "in place" protection.
• Ex-situ = "out of place" protection.
• Hotspots and protected areas are natural refuges.
• Gene banks and seed banks preserve genetic material.

Quick Checkpoints

• What are the two main conservation strategies?
• Give examples of in-situ conservation methods.
• What is ex-situ conservation?

In-situ Conservation

Definition and Types

• Protection of whole ecosystems and biodiversity in natural habitats.
• Two types: Hotspots and Protected Areas.
• Hotspots: Areas rich in unique species, sensitive to human impact; 34 globally, 3 in India.
• Protected Areas:
  • National Parks: Strict wildlife protection, no farming or grazing.
  • Biosphere Reserves: UNESCO zones - Core (no human activity), Buffer (limited research), Transition (sustainable use).
  • Sanctuaries: Protect animals, allow limited human use like grazing.
• India's sacred groves protect rare endemic species; found in Meghalaya, Rajasthan, Western Ghats, Madhya Pradesh.

Memory Aids

• Hotspots = high diversity, high threat.
• National Parks = strict protection.
• Biosphere Reserves = three zones for balance.
• Sanctuaries = protection with limited use.
• Sacred groves = cultural conservation.

Quick Checkpoints

• What defines a biodiversity hotspot?
• What activities are allowed in biosphere reserve zones?
• Where are sacred groves found in India?

Ex-situ Conservation

Definition and Methods

• Conservation of species outside their natural habitats.
• Includes offsite collections and gene banks.
• Offsite Collections: Botanical gardens, zoos, wildlife parks breed and preserve species.
• Gene Banks: Maintain seeds, live plants, genetic material.
• Seed Banks: Orthodox seeds (dry/cold tolerant) and recalcitrant seeds (sensitive).
• Orchards: Maintain plants with recalcitrant seeds.
• Tissue Culture: Multiply plants using pollen, embryos; useful for endangered species.
• Cryopreservation: Freeze cells/tissues at -196°C for long-term preservation.

Memory Aids

• Offsite = gardens and zoos.
• Gene banks = genetic diversity storage.
• Orthodox seeds = dry and cold tolerant.
• Recalcitrant seeds = sensitive seeds.
• Tissue culture = rapid multiplication.
• Cryopreservation = ultra-cold storage.

Quick Checkpoints

• What is ex-situ conservation?
• How do seed banks differ for orthodox and recalcitrant seeds?
• What is the role of tissue culture in conservation?

International Efforts

Key Agreements and Organisations

• Earth Summit (1992): Promoted Convention on Biological Diversity (CBD), signed by 152 nations; India joined in 1994.
• Commitments:
  • Conserve biodiversity.
  • Manage biodiversity sustainably.
  • Share benefits equitably.
• Earth Summit (Rio+20, 2012): New sustainable development strategies.
• NGOs like Greenpeace support conservation globally.
• Agenda 21: Blueprint for sustainable development in 21st century.
• World Conservation Union (IUCN): Leadership in conservation.
• World Wide Fund for Nature (WWF): Conservation support.
• CITES: Restricts trade in endangered species, helps prevent poaching.
• UNESCO's Man and Biosphere (MAB) program supports biosphere reserves.

Memory Aids

• CBD = global biodiversity treaty.
• Agenda 21 = 21st-century sustainability plan.
• CITES = trade control for endangered species.
• IUCN and WWF = global conservation leaders.

Quick Checkpoints

• What is the purpose of the Convention on Biological Diversity?
• Which organisations support global biodiversity conservation?
• What does CITES regulate?

Biodiversity Conservation in India

National Efforts

• In-situ conservation managed by Ministry of Environment and Forests.
• Ex-situ conservation managed by National Bureau of Plant, Animal and Fish Genetic Resources.
• International Crop Research Institute for Semi-Arid Tropics (ICRISAT) conserves germplasm of key crops.
• Multiple centres maintain diverse crop varieties for conservation.

Memory Aids

• Ministry of Environment = in-situ.
• National Bureau = ex-situ genetic resources.
• ICRISAT = crop germplasm conservation.

Quick Checkpoints

• Who manages in-situ conservation in India?
• What is the role of ICRISAT?
• Which organisation handles ex-situ conservation?