Unit 3: Biodiversity and conservation - Subjective Questions

Biodiversity refers to the variety and variability of living organisms and the ecological complexes of which they are a part. It includes diversity within species, between species, and of ecosystems.

Significance of biodiversity:

• It maintains ecological balance and ecosystem stability.
• It supports food chains, nutrient cycling, pollination, and decomposition.
• It provides food, medicine, fuel, fibre, and other resources.
• It increases the ability of ecosystems to withstand environmental changes.
• It has cultural, spiritual, recreational, aesthetic, and educational importance.
• It provides genetic resources for crop improvement and scientific research.

Thus, biodiversity is essential for both the functioning of ecosystems and human well-being.

Biological diversity occurs at three major levels:

1. Genetic diversity: It is the variation in genes among individuals of the same species. For example, different varieties of rice, mango, or wheat show genetic diversity.

2. Species diversity: It refers to the variety and relative abundance of different species in a particular region. A forest containing trees, mammals, birds, reptiles, insects, fungi, and microorganisms has high species diversity.

3. Ecosystem diversity: It is the variety of ecosystems, habitats, and ecological processes in a geographical area. Examples include forests, grasslands, wetlands, deserts, coral reefs, and mangroves.

These levels are interdependent. Loss of genetic diversity can weaken species, while species loss can disturb entire ecosystems.

Genetic diversity is the variation in hereditary characteristics among individuals of the same species. It results from mutations, genetic recombination, and gene flow.

Importance:

• It enables populations to adapt to environmental changes.
• It increases resistance to diseases, pests, and climatic stress.
• It reduces the risk of extinction caused by inbreeding.
• It provides useful traits for developing improved crop and livestock varieties.
• It forms the basic material for natural selection and evolution.

For example, traditional crop varieties may contain genes for drought tolerance or disease resistance. Conserving such varieties is important for future food security.

Species diversity refers to the variety of species present in a community and their relative abundance.

It has two major components:

• Species richness: The total number of different species present in an area. A forest containing 100 species has greater richness than one containing 50 species.
• Species evenness: The degree to which individuals are distributed equally among the species. A community in which all species have similar populations has high evenness.

A habitat may have high species richness but low evenness if one species is overwhelmingly dominant. Both richness and evenness are important for assessing the overall diversity and ecological health of a community.

Ecosystem diversity is the variety of ecosystems, habitats, communities, and ecological processes within a region. Examples include Himalayan forests, coastal mangroves, deserts, grasslands, rivers, wetlands, and coral reefs.

Importance in conservation:

• Different ecosystems support different groups of plants and animals.
• It protects a wide range of habitats and ecological niches.
• It maintains processes such as nutrient cycling, water purification, and carbon storage.
• It increases resilience against droughts, floods, climate change, and other disturbances.
• It preserves genetic and species diversity associated with each ecosystem.

Conservation planning must therefore protect representative examples of all major ecosystems rather than focusing on only a few attractive species.

Biodiversity has several important values:

• Ecological value: Organisms maintain food webs, pollination, decomposition, soil formation, nutrient cycling, and ecosystem stability.
• Economic value: Biodiversity supplies food, timber, medicines, fibres, fuel, fisheries, livestock resources, and materials for industries.
• Social value: Plants and animals are associated with traditions, religious beliefs, festivals, indigenous knowledge, and community identity.
• Aesthetic value: Natural landscapes, wildlife, flowers, forests, and coral reefs provide beauty, recreation, tourism, and inspiration.
• Informational value: Organisms provide genetic, biochemical, ecological, and scientific information useful in medicine, agriculture, biotechnology, and education.

These values show that biodiversity is valuable even when it has no immediate commercial use.

Ecosystem services are the benefits that humans obtain from ecosystems. They are commonly grouped into four categories:

1. Provisioning services: Products obtained from ecosystems, such as food, fresh water, timber, fuelwood, fibres, medicines, and genetic resources.
2. Regulating services: Natural regulation of ecological processes, including climate regulation, flood control, pollination, erosion control, water purification, and disease regulation.
3. Cultural services: Non-material benefits such as recreation, tourism, spiritual experiences, education, cultural identity, and aesthetic enjoyment.
4. Supporting services: Basic processes necessary for other services, including soil formation, photosynthesis, nutrient cycling, and primary production.

Human survival and economic development depend heavily on these services, although many are not directly priced in markets.

Biodiversity hotspots are regions that contain exceptionally high levels of endemic species but are also facing severe habitat loss and other threats.

A region is generally recognized as a hotspot when it:

• Contains at least 1,500 endemic species of vascular plants.
• Has lost at least 70 percent of its original natural vegetation.

Indian regions associated with global hotspots include:

• The Himalaya.
• The Indo-Burma region, including parts of northeastern India.
• The Western Ghats and Sri Lanka region.
• The Sundaland hotspot, represented in India by the Nicobar Islands.

Hotspots receive conservation priority because protecting a relatively small area can save a large number of unique species.

The major threats to biodiversity include:

• Habitat loss and fragmentation: Conversion of forests, wetlands, and grasslands for agriculture, industries, roads, dams, and cities reduces living space and isolates populations.
• Poaching and illegal wildlife trade: Excessive hunting and collection reduce animal and plant populations and may cause local or total extinction.
• Biological invasions: Non-native species may compete with, prey upon, or transmit diseases to native species.
• Human-wildlife conflicts: Crop damage, livestock predation, property loss, and threats to human life often lead to retaliatory killing of animals.
• Pollution and climate change: Toxic substances, altered temperature, changing rainfall, ocean acidification, and extreme events disturb reproductive and ecological processes.

These threats may reduce population size, genetic variation, ecosystem stability, and the availability of ecosystem services.

Habitat loss occurs when a natural habitat is destroyed or converted into another land use. Habitat fragmentation occurs when a large continuous habitat is divided into smaller, isolated patches.

Major causes:

• Agricultural expansion and urbanization.
• Mining, industries, roads, railways, dams, and power projects.
• Deforestation, overgrazing, and drainage of wetlands.

Ecological consequences:

• Reduction in available food, shelter, and breeding sites.
• Decline in population size and genetic diversity.
• Isolation of populations and reduced gene flow.
• Increased edge effects, such as higher temperature, wind, and predation.
• Greater human-wildlife conflict.
• Disruption of migration routes and ecological processes.

Wildlife corridors, habitat restoration, protected areas, and sustainable land-use planning can reduce these effects.

Poaching is the illegal hunting, capturing, killing, or collection of wild animals and plants. It may be carried out for meat, skins, horns, bones, medicines, pets, trophies, or illegal trade.

Effects:

• Decline in wildlife populations.
• Disruption of food chains and ecological relationships.
• Loss of breeding adults and genetic diversity.
• Increased risk of extinction.
• Economic losses to ecotourism and local communities.

Control measures:

• Strict enforcement of wildlife protection laws.
• Patrolling, surveillance, camera traps, and intelligence networks.
• Regulation of markets and international trade.
• Community participation and alternative livelihood programmes.
• Public awareness and reduction of demand for wildlife products.
• Strong penalties and cooperation among states and countries.

A biological invasion occurs when a non-native species becomes established and spreads in a new region, causing ecological, economic, or health-related harm. Such organisms are called invasive alien species.

Impacts include:

• Competition with native species for food, water, light, and space.
• Predation on native organisms that lack suitable defenses.
• Introduction of diseases and parasites.
• Hybridization and genetic contamination of native species.
• Alteration of fire regimes, nutrient cycles, soil conditions, and water availability.
• Reduction in species richness and ecosystem productivity.

Examples include water hyacinth in aquatic systems and Lantana in forest habitats. Prevention, early detection, mechanical removal, biological control, and habitat restoration are important management strategies.

Human-wildlife conflict occurs when the needs or activities of people and wild animals negatively affect each other. It commonly arises because of habitat loss, fragmentation, expansion of agriculture, settlement near forests, blocked migration routes, and scarcity of food or water.

Consequences:

• Crop damage, livestock loss, property destruction, and human injuries.
• Retaliatory killing or capture of wildlife.
• Fear and economic hardship among local communities.
• Decline of threatened animal populations.

Mitigation measures:

• Protect and restore habitats and wildlife corridors.
• Use fencing, trenches, early-warning systems, and safe livestock enclosures.
• Provide timely compensation for losses.
• Develop community-based conservation programmes.
• Improve waste management to prevent attracting animals.
• Promote scientific land-use planning and awareness programmes.

Species of conservation concern are categorized according to their population status, distribution, threats, and evolutionary importance.

• Extinct species: Species for which no living individual remains anywhere in the world.
• Endangered species: Species facing a very high risk of extinction in the near future because of severe population decline, restricted range, or serious threats.
• Vulnerable species: Species likely to become endangered if the factors causing population decline continue.
• Rare species: Species with small populations or restricted geographical distribution. They may not currently be endangered but are susceptible to future threats.
• EDGE species: EDGE means Evolutionarily Distinct and Globally Endangered. These species have few close relatives and are also at high risk of extinction. They represent unique evolutionary history and require focused conservation.

These categories help governments and conservation agencies prioritize action.

Key distinction: Endangered status is primarily associated with a very high extinction risk, vulnerable status indicates a lower but significant future risk, and rarity describes limited population size or distribution without necessarily indicating a current high extinction risk.

In-situ conservation means conserving species in their natural habitats where they continue to interact with other organisms and natural ecological processes.

Major methods in India include:

• National parks.
• Wildlife sanctuaries.
• Biosphere reserves.
• Conservation reserves and community reserves.
• Sacred groves and protected wetlands.
• Protection of wildlife corridors and natural habitats.

Advantages:

• Conserves entire ecosystems and many species together.
• Maintains natural behavior, reproduction, and evolution.
• Protects genetic diversity and ecological interactions.
• Allows species to adapt to changing environmental conditions.
• Conserves ecosystem services and cultural landscapes.

In-situ conservation is generally the preferred method for maintaining viable wild populations over the long term.

Ex-situ conservation is the protection and maintenance of species outside their natural habitats. Examples include zoos, botanical gardens, aquaria, seed banks, gene banks, tissue culture laboratories, cryopreservation facilities, and captive-breeding centres.

Ex-situ conservation is especially useful for species whose wild populations are critically small, habitats are severely damaged, or immediate rescue and breeding are necessary. Ideally, ex-situ efforts should support later reintroduction into natural habitats.

India is divided into major biogeographic zones based on climate, physiography, vegetation, and animal life. The commonly recognized zones are:

1. Trans-Himalaya: Cold deserts and high-altitude regions.
2. Himalaya: Mountain ecosystems with forests, alpine meadows, and high endemism.
3. Indian Desert: Arid landscapes, dunes, and specialized desert species.
4. Semi-arid zone: Grasslands, thorn forests, and scrub habitats.
5. Western Ghats: Evergreen forests, high rainfall, and exceptional endemism.
6. Deccan Peninsula: Plateaus, deciduous forests, and grasslands.
7. Gangetic Plain: Fertile plains, rivers, wetlands, and agricultural landscapes.
8. Northeast India: Rainforests, hills, and rich Indo-Burmese biodiversity.
9. Islands: Andaman, Nicobar, and Lakshadweep ecosystems with many endemic species.
10. Coasts: Mangroves, estuaries, beaches, coral reefs, and marine habitats.

This classification helps identify representative ecosystems, prioritize protected areas, and design region-specific conservation strategies.

India is considered a mega-diversity nation because it contains an exceptionally large variety of ecosystems, species, and genetic resources within its geographical area.

Factors responsible:

• Wide variation in climate, altitude, rainfall, temperature, and soil.
• Presence of mountains, plateaus, plains, deserts, forests, wetlands, islands, and coastal ecosystems.
• Location at the meeting point of several biogeographic regions.
• Long coastline and diverse marine environments.
• Presence of biodiversity hotspots such as the Himalaya, Western Ghats, Indo-Burma, and Nicobar-related Sundaland region.
• High levels of species endemism, especially in the Western Ghats, northeastern region, Himalaya, and islands.
• Large genetic diversity in crops, livestock, medicinal plants, and wild relatives.
• Numerous traditional communities possessing valuable ecological knowledge.

India's biodiversity requires both ecosystem-level protection and community-based conservation.

A comprehensive biodiversity conservation strategy should combine habitat protection, species recovery, sustainable development, and community participation.

Major components:

• Expand and effectively manage national parks, wildlife sanctuaries, biosphere reserves, wetlands, and marine protected areas.
• Protect biodiversity hotspots, endemic species, wildlife corridors, and important habitats.
• Restore degraded forests, grasslands, wetlands, mangroves, and coral reefs.
• Control poaching, illegal trade, pollution, invasive species, and unsustainable resource extraction.
• Use ex-situ facilities such as seed banks, gene banks, zoos, botanical gardens, and captive-breeding programmes for highly threatened species.
• Reintroduce captive-bred or rescued organisms into suitable natural habitats after scientific assessment.
• Involve local and indigenous communities through benefit sharing, sustainable livelihoods, and participatory monitoring.
• Strengthen environmental education, biodiversity databases, research, and long-term monitoring.
• Address climate change through ecosystem restoration and climate-resilient conservation planning.

Integration of in-situ and ex-situ approaches provides both immediate protection and long-term ecological security.