Biodiversity

Biodiversity encompasses millions of distinct biological species on Earth, a result of four billion years of evolution. It includes all forms of life, the genetic variation within these forms, and their complex interrelations within ecosystems. This interconnectedness is vital for the sustainability of life and environment.

Learning Outcomes:

1. Understand the levels and measurement of biodiversity.
2. Explore the services provided by biodiversity.
3. Identify causes of biodiversity loss.
4. Learn the modes and significance of biodiversity conservation.
5. Comprehend IUCN classification of conservation priority.

Biodiversity Overview

Biodiversity refers to the variety and variability of life on Earth, including terrestrial, marine, and aquatic ecosystems. It covers the diversity within species, between species, and of ecosystems. Conservation and sustainable use of biodiversity are essential for ecological stability, forming a fundamental part of human existence.

Levels of Biodiversity

Biodiversity exists at three fundamental levels:

1. Genetic Diversity: This involves the variation in genes within a particular species, allowing adaptation to environmental changes and ensuring species survival.
2. Species Diversity: Represents the variety of living organisms on Earth. Species differ genetically, and the ratio of one species’ population to the total number of organisms in a biome defines its diversity.
3. Ecosystem Diversity: Refers to different habitats formed by a region’s climate, vegetation, and geography. Examples include coral reefs, deserts, wetlands, and rainforests. Changes in environmental conditions influence the diversity within an ecosystem.

Important Note: Closely related species, like humans and chimpanzees, share about 98.4% of their genetic makeup.

Measurement of Biodiversity

Biodiversity is measured primarily through:

1. Species Richness: The number of species found within a community.

• Alpha Diversity: Diversity within a specific area or ecosystem.
• Beta Diversity: Comparison of species diversity between different ecosystems.
• Gamma Diversity: Overall diversity across multiple ecosystems within a region.

1. Species Evenness: Indicates the proportion of species at a given site. Low evenness suggests dominance by a few species.

Biodiversity and Food Web

Life’s building blocks (carbon, oxygen, nitrogen, hydrogen) cycle through ecosystems. Producers (green plants) absorb nutrients and produce energy, while consumers (animals and humans) depend on these producers or other consumers. Food chains link producers to consumers, forming complex food webs crucial for ecological balance.

Important Note: Disrupting food chains can have cascading negative effects, pushing multiple species closer to extinction.

Services Provided by Biodiversity

Biodiversity supports essential natural, biological, and social services:

1. Ecosystem Services: Protection of water resources, soil formation, nutrient cycling, pollution breakdown, climate stability, and ecosystem maintenance.
2. Biological Services: Provides food, medicinal resources, timber, ornamental plants, genetic diversity, and breeding stocks.
3. Social Services: Research and education opportunities, recreation and tourism, and cultural values.

Causes for Biodiversity Loss

Biodiversity loss results from species extinction or habitat destruction. Common causes include:

1. Natural Causes: Floods, earthquakes, landslides, rivalry among species, lack of pollination, and diseases.
2. Man-Made Causes: Habitat destruction, commercial exploitation, hunting, agricultural expansion, pollution, wetland filling, and coastal destruction.

Biodiversity Conservation

Conserving biodiversity is crucial to preserve ecological diversity and food chain continuity. Conservation methods are categorized as:

1. Ex-situ Conservation: Protects biodiversity outside its natural habitat.

• Examples: Zoological parks, botanical gardens, seed banks.
• Reintroduction: The Gangetic gharial has been reintroduced to rivers where it had become extinct.

1. In-situ Conservation: Conserves species within their natural habitats.

• Examples: National parks, sanctuaries, biosphere reserves, and protected forests.

Important Note: Constraints in biodiversity conservation include low prioritization, exploitation for monetary gain, and inadequate species knowledge.

Botanical Garden

Botanical gardens are scientifically planned collections of diverse plants. They serve purposes like studying plant taxonomy, acclimatizing exotic plants, conserving germplasm, developing hybrids, and preserving threatened species.

Zoo

A Zoo is an establishment where captive animals are kept for exhibition and conservation. Zoos have evolved from centers of entertainment to pivotal wildlife conservation and educational institutions. They now play a crucial role in species conservation through captive breeding.

The Red Data Book

Species judged as threatened are listed in the Red Data Book, published by the International Union for Conservation of Nature (IUCN). It contains up-to-date information on endangered species, symbolized by the color “red” to denote danger.

IUCN Classification of Conservation Priority

The IUCN categorizes species based on their risk of extinction:

1. Extinct (EX): No reasonable doubt that the last individual has died.
2. Extinct in the Wild (EW): Species survive only in captivity or as a naturalized population outside their historic range.
3. Critically Endangered (CR): Species facing an extremely high risk of extinction with criteria like:

• Population reduction of over 90% in 10 years.
• Less than 50 mature individuals.

1. Endangered (EN): High risk of extinction with criteria including:

• Population reduction of 70% in 10 years.
• Fewer than 250 mature individuals.

1. Vulnerable (VU): High risk of extinction in the wild, with criteria such as:

• Population reduction of 50% over the last 10 years.
• Fewer than 10,000 mature individuals.

1. Near Threatened (NT): Close to qualifying as threatened in the near future.
2. Least Concern (LC): Species widespread and abundant, not qualifying for any threatened categories.
3. Data Deficient (DD): Insufficient information to assess the species’ risk of extinction.
4. Not Evaluated (NE): Species not yet evaluated against criteria.

Important Note: The number of species in the pink pages (critically endangered) is increasing, while the green pages (species recovering) remain few.

India’s Biodiversity

India is one of the mega-diverse countries, accounting for nearly 7% of the world’s recorded species while supporting 18% of the human population. The diversity in its ecosystems and habitats, ranging from forests to wetlands, stems from varied climatic, topographic, and edaphic conditions.

India Represents:

1. Two Realms: The Himalayan (Palearctic) and Malayan Realms.
2. Five Biomes: Distinct ecological communities adapted to particular climates.
3. Ten Bio-geographic Zones: Regions with specific ecological and geographical characteristics.
4. Twenty-Five Bio-geographic Provinces: Subdivisions representing unique biodiversity.

Concept: Biogeographic realms are large spatial regions sharing broadly similar biota, influenced by geography and climate.

Modes of Conservation

Conservation is approached through ex-situ (outside natural habitat) and in-situ (within natural habitat) methods. Ex-situ strategies include botanical gardens, zoos, and seed banks, while in-situ efforts involve creating protected areas like national parks, biosphere reserves, and forests.

Conservation Mode	Description	Examples
Ex-situ	Conservation outside natural habitats	Zoos, botanical gardens, seed banks
In-situ	Conservation within natural habitats	National parks, biosphere reserves

Causes of Extinction

Species extinction may occur due to:

1. Natural Causes: Natural disasters, species rivalry, diseases, etc.
2. Human Activities: Urbanization, agriculture, industrial development, habitat destruction, hunting, and poaching.

Measurement Techniques Comparison

Measurement Component	Description
Species Richness	Total number of species in an ecosystem
Species Evenness	Proportion of each species in the ecosystem
Alpha Diversity	Diversity within a specific area
Beta Diversity	Comparison between different ecosystems
Gamma Diversity	Overall diversity within a region

Learning Insight: Conservation efforts must prioritize both species richness and evenness to maintain ecological balance.

Key Conservation Challenges

Conservation faces constraints like low prioritization of natural resources, monetary exploitation, inadequate knowledge, and the impact of unplanned urbanization.

Important Note: Conservation of biodiversity is intertwined with the cultural, economic, and ecological stability of human societies.

MCQ: Which of the following is an example of in-situ conservation?

1. Seed bank
2. National park
3. Botanical garden
4. Zoo
   Answer: 2. National park