18.10 Biodiversity

Definition

• Biodiversity: The degree of variation in life forms within an ecosystem.
• Goes beyond simply listing species; encompasses three key levels:
  1. Ecosystem Diversity:
  • The variety of ecosystems and habitats present in an area.
  • Includes the different physical environments (e.g., forests, wetlands, grasslands) and their interactions.
  1. Species Diversity:
  • The number of species in an ecosystem and their relative abundance (balance of population sizes among species).
  1. Genetic Diversity:
  • Variation in genes within a species, contributing to adaptability and resilience.

Importance of Biodiversity

• Ecosystem Services:
  • Provides essential functions like pollination, nutrient cycling, water purification, and climate regulation.
• Species Interdependence:
  • Ensures stability of food webs and resilience against environmental changes.
• Genetic Resources:
  • Offers genetic material for agriculture, medicine, and biotechnology.
• Cultural and Aesthetic Value:
  • Enhances human well-being and connects to cultural heritage.

Global Biodiversity Hotspots

• Areas with high species richness and unique endemic species.
• Examples of biodiversity-rich regions:

1. Congo Basin (Africa):
   • Vast tropical rainforest with unique species like okapi and gorillas.
2. South East Asia:
   • Includes tropical rainforests in Indonesia, Malaysia, and the Philippines.
3. Amazon Rainforest (South America):
   • Home to one-tenth of all known species, including jaguars and anacondas.
4. Caribbean and Central America:
   • Rich in coral reefs and tropical rainforests with many endemic species.
5. South-West Australia:
   • Contains unique plant and animal species found nowhere else.
6. New Zealand:
   • Isolation over millions of years has resulted in unique species like:
   • Tuatara (Sphenodon sp.): A living fossil endemic to New Zealand.
   • Flightless birds like the kiwi and kakapo.

Endemism

• Definition: Species that are native to and found only in a specific geographical region.
• Examples:
  • Tuatara:
    • Found only in New Zealand.
    • Survived extinction in other parts of the world due to New Zealand’s prolonged isolation.
  • Galápagos Tortoises:
    • Endemic to the Galápagos Islands.

Threats to Biodiversity

• Habitat Loss:
  • Deforestation, urbanization, and agriculture.
• Climate Change:
  • Alters ecosystems and shifts species distributions.
• Pollution:
  • Contaminates habitats and harms species.
  • Overexploitation:
    • Unsustainable hunting, fishing, and resource extraction.
  • Invasive Species:
    • Non-native species that outcompete or prey on endemic ones.

Conservation Efforts

• Protected Areas:
  • Establishing national parks, reserves, and wildlife sanctuaries.
• Sustainable Practices:
  • Promoting eco-friendly agriculture and reducing overexploitation.
• Restoration Ecology:
  • Rehabilitating degraded ecosystems.
• Community Involvement:
  • Empowering local populations to participate in conservation.

FIGURE

• Figure A:
  • Highlights the tuatara (Sphenodon sp.), a unique endemic species from New Zealand.
  • Demonstrates how geographical isolation supports biodiversity and prevents extinction of unique species.

Summary

• Biodiversity includes diversity at ecosystem, species, and genetic levels.
• Biodiversity hotspots like the Congo Basin, Amazon, and New Zealand are rich in species, many of which are endemic due to long-term isolation or unique conditions.
• Protecting biodiversity is vital for ecological stability, human well-being, and sustaining natural resources.