Unit 3: Biodiversity and conservation - Subjective Questions

Biodiversity refers to the variety and variability of living organisms, including diversity within species, between species, and of ecosystems.

Its importance includes:

• Maintaining ecological balance and ecosystem stability.
• Supporting food chains and nutrient cycling.
• Providing food, fuel, medicines, fibre, and genetic resources.
• Increasing the ability of ecosystems to withstand environmental changes.
• Supporting livelihoods, culture, recreation, and scientific research.
• Preserving evolutionary potential for future generations.

Biological diversity is studied at three major levels:

• Genetic diversity: Variation in genes within a species. For example, different varieties of rice, mango, or cattle breeds show genetic diversity.
• Species diversity: Variety and relative abundance of different species in a particular region. A tropical forest containing trees, birds, insects, mammals, and microorganisms has high species diversity.
• Ecosystem diversity: Variety of ecosystems, habitats, and ecological processes in a geographical area. Forests, grasslands, wetlands, deserts, rivers, and marine ecosystems represent ecosystem diversity.

These levels are interrelated and together form the overall biodiversity of a region.

Genetic diversity is the variation in hereditary characteristics among individuals of the same species. It arises through mutation, recombination, and gene flow.

Its significance includes:

• Enabling populations to adapt to climate change, diseases, pests, and environmental stress.
• Providing the raw material for natural selection and evolution.
• Reducing the risk of extinction caused by inbreeding.
• Supporting the development of improved crops and livestock.
• Preserving useful traits such as drought tolerance, disease resistance, and high productivity.

A population with greater genetic diversity generally has a better chance of surviving changing environmental conditions.

Species diversity refers to the variety of species and their relative abundance in a given area. It includes both species richness and species evenness. For example, a rainforest may contain many species of plants, animals, fungi, and microorganisms.

Ecosystem diversity refers to the variety of ecosystems, habitats, communities, and ecological processes within a region. Examples include wetlands, forests, deserts, coral reefs, and grasslands.

Difference: Species diversity focuses on variation among living species, whereas ecosystem diversity focuses on variation among habitats and ecological systems. Ecosystem diversity provides the physical settings in which species live and interact.

Biodiversity has several important values:

• Ecological value: It maintains food webs, pollination, decomposition, soil formation, nutrient cycling, climate regulation, and ecosystem stability.
• Economic value: It provides food, timber, fuelwood, fibres, medicines, genetic resources, and raw materials for industries.
• Social value: Plants and animals are associated with traditional knowledge, customs, religion, festivals, and the cultural identity of communities.
• Aesthetic value: Natural landscapes and wildlife provide beauty, recreation, tourism, inspiration, and mental well-being.
• Informational value: Organisms provide knowledge about evolution, ecological processes, genetics, medicine, agriculture, and potential future discoveries.

Ecosystem services are the benefits that humans obtain directly or indirectly from ecosystems.

They are classified as follows:

• Provisioning services: Products obtained from ecosystems, such as food, freshwater, timber, fuel, fibres, and medicines.
• Regulating services: Benefits from regulation of ecological processes, including climate regulation, flood control, pollination, water purification, and disease regulation.
• Cultural services: Non-material benefits such as spiritual value, recreation, tourism, education, and aesthetic enjoyment.
• Supporting services: Basic processes necessary for other services, including soil formation, photosynthesis, nutrient cycling, and habitat provision.

Ecosystem services support human survival, economic activities, health, and social well-being. Biodiversity strengthens these services by making ecosystems more productive and resilient.

A biodiversity hotspot is a region that contains exceptionally high levels of endemic species but is facing severe habitat loss and other threats.

According to the commonly used criteria, a hotspot must:

• Contain at least 1,500 endemic species of vascular plants.
• Have lost at least 70% of its original natural vegetation.

Hotspots are significant because:

• They contain species found nowhere else in the world.
• They represent areas where conservation action can prevent many extinctions.
• They help prioritize limited financial and scientific resources.
• Protection of hotspots also safeguards ecosystem services and local livelihoods.

Examples associated with India include the Himalaya, Indo-Burma, Western Ghats and Sri Lanka, and Sundaland, which includes the Nicobar Islands.

The major threats to biodiversity include habitat destruction, overexploitation, biological invasions, pollution, climate change, and human-wildlife conflict.

Habitat loss occurs when natural habitats are converted for agriculture, industries, roads, dams, mining, settlements, and urban development. It is the most important cause of biodiversity decline.

Habitat fragmentation divides a large continuous habitat into smaller isolated patches. This:

• Reduces available space and population size.
• Restricts movement and gene flow.
• Increases edge effects and exposure to predators or invasive species.
• Prevents migration and breeding of wildlife.

Habitat degradation reduces the quality of a habitat through pollution, overgrazing, deforestation, altered water flow, and excessive resource extraction. Conservation requires protected areas, habitat restoration, wildlife corridors, sustainable land use, and environmental impact assessment.

Poaching is the illegal hunting, capturing, or killing of wild animals and the illegal collection of plants. It is driven by demand for meat, skins, horns, bones, medicines, pets, and ornamental products. Poaching reduces population size, disrupts food webs, and may cause local or global extinction.

Biological invasions occur when non-native species enter a new habitat, become established, spread rapidly, and harm native species or ecosystems. Invasive species may compete for resources, prey on native organisms, transmit diseases, or alter ecosystem processes.

Control measures include:

• Strict enforcement of wildlife protection laws.
• Monitoring, patrolling, and regulation of wildlife trade.
• Community participation and alternative livelihoods.
• Quarantine and screening of imported organisms.
• Early detection and rapid removal of invasive species.
• Restoration of native habitats and public awareness.

Human-wildlife conflict occurs when the needs or activities of humans and wild animals negatively affect each other. Examples include crop damage by elephants, livestock predation by large carnivores, attacks on people, and damage to property.

Causes:

• Habitat loss and fragmentation.
• Expansion of agriculture, roads, industries, and settlements.
• Blockage of wildlife corridors.
• Scarcity of food and water in natural habitats.
• Increasing human and wildlife populations.

Effects:

• Human injury, death, and economic loss.
• Retaliatory killing of wildlife.
• Loss of public support for conservation.

Management:

• Protect and restore habitats and corridors.
• Use early-warning systems, fencing, barriers, and safe livestock enclosures.
• Provide timely compensation for losses.
• Involve local communities in conservation.
• Use scientific monitoring and translocation only when necessary.

The categories indicate different levels of conservation concern:

• Extinct species: Species for which no reasonable doubt remains that the last individual has died.
• Endangered species: Species facing a very high risk of extinction in the wild because of a severe decline in population, restricted range, or other threats.
• Vulnerable species: Species likely to become endangered if the threats affecting them continue.
• Rare species: Species with small populations or restricted distribution that may not currently be threatened but are at risk because of their limited occurrence.
• EDGE species: Species that are Evolutionarily Distinct and Globally Endangered. They have few close relatives and are also at high risk of extinction.

These categories help governments and conservation organizations set priorities for research, protection, recovery, and habitat management.

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

Examples include:

• National parks.
• Wildlife sanctuaries.
• Biosphere reserves.
• Community reserves.
• Sacred groves and protected forests.

Advantages:

• Protects entire ecosystems and many species simultaneously.
• Allows natural evolution, adaptation, breeding, and ecological interactions.
• Conserves genetic diversity within natural populations.
• Protects ecosystem services and cultural landscapes.

Limitations:

• It may be difficult where habitats are already highly fragmented.
• Protected areas can face poaching, invasive species, pollution, and human-wildlife conflict.
• Very small or critically threatened populations may not recover without additional intervention.

Ex-situ conservation is the protection and maintenance of organisms outside their natural habitats under controlled conditions.

Examples include:

• Zoos and aquariums.
• Botanical gardens and arboreta.
• Seed banks and gene banks.
• Pollen, tissue, and DNA banks.
• Captive breeding and artificial propagation programs.

Comparison:

• In-situ conservation protects organisms in their natural ecosystems, whereas ex-situ conservation protects them outside those ecosystems.
• In-situ methods preserve natural interactions and evolutionary processes, whereas ex-situ methods provide controlled care and intensive management.
• In-situ conservation is generally preferred for ecosystem protection, while ex-situ conservation is useful for critically endangered species, genetic storage, research, and later reintroduction.

The two approaches should be used together for effective conservation.

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

• Trans-Himalaya: Cold deserts and high-altitude ecosystems.
• Himalaya: Mountain forests, alpine meadows, and high endemism.
• Indian Desert: Arid ecosystems of Rajasthan and adjoining areas.
• Semi-Arid: Grasslands, scrublands, and seasonal habitats.
• Western Ghats: Tropical forests with high rainfall and endemism.
• Deccan Peninsula: Plateaus, deciduous forests, and grasslands.
• Gangetic Plain: Fertile plains, rivers, wetlands, and agricultural landscapes.
• North-East India: Rainforests, hills, and exceptional species richness.
• Islands: Andaman, Nicobar, and Lakshadweep ecosystems with many endemic species.
• Coasts: Mangroves, estuaries, beaches, coral reefs, and marine habitats.

These zones help identify ecological regions, plan protected areas, conserve representative habitats, and develop region-specific management strategies.

India is considered a mega-diversity nation because it has exceptionally high species richness, genetic diversity, ecosystem diversity, and endemism.

Reasons include:

• Great variation in climate, altitude, rainfall, and soil.
• Presence of mountains, plateaus, deserts, forests, grasslands, wetlands, islands, coasts, and marine ecosystems.
• Location at the junction of several biogeographic regions.
• Presence of global biodiversity hotspots such as the Himalaya, Western Ghats, Indo-Burma, and Sundaland regions.
• Large numbers of endemic plants and animals.
• Rich agricultural diversity, including numerous traditional crop varieties and livestock breeds.
• Extensive cultural and traditional knowledge related to biological resources.

India's biodiversity supports food security, livelihoods, ecosystem services, medicine, tourism, and cultural traditions. Its conservation is therefore important nationally and globally.

Both methods are complementary. In-situ conservation should generally be the primary approach, while ex-situ methods provide additional support.

Biodiversity threats often act together rather than independently.

• Habitat loss reduces living space and separates populations.
• Overexploitation, including poaching, hunting, fishing, and collection, decreases populations faster than they can recover.
• Invasive species compete with, prey upon, or infect native organisms, especially in disturbed habitats.
• Pollution contaminates air, water, and soil and may cause poisoning, reproductive failure, and eutrophication.
• Climate change alters temperature, rainfall, sea level, seasonal cycles, and species distributions.

These threats can produce a synergistic effect. For example, habitat fragmentation may reduce a population's genetic diversity, making it less able to adapt to climate change or resist disease. Effective conservation must therefore use integrated approaches such as habitat protection, sustainable resource use, pollution control, invasive-species management, climate adaptation, and ecological restoration.

Effective biodiversity conservation requires both ecological protection and social cooperation.

• Protected areas such as national parks, wildlife sanctuaries, and biosphere reserves protect habitats, breeding populations, and ecological processes from destructive activities.
• Wildlife corridors connect fragmented habitats and allow animals to move for feeding, breeding, seasonal migration, and gene flow. They reduce isolation and road-related mortality.
• Community participation includes involving local people in planning, monitoring, habitat restoration, sustainable harvesting, and benefit sharing. It also recognizes traditional ecological knowledge.

These approaches are important because protected areas alone may be too small or isolated. Local communities can help prevent poaching, reduce conflict, and support long-term conservation when their rights and livelihoods are respected.

A species of conservation concern is a species whose population, habitat, distribution, or future survival is threatened or requires special protection. Such species may be extinct, endangered, vulnerable, rare, or evolutionarily distinct and globally endangered.

Prioritization is necessary because:

• Conservation funds and personnel are limited.
• Some species face a much higher risk of extinction than others.
• Species with unique evolutionary history may represent irreplaceable biodiversity.
• Protecting umbrella or keystone species can conserve many other organisms and habitats.
• Early action is usually more effective and less expensive than emergency recovery after severe decline.

Priorities are determined using population trends, range size, habitat quality, threat intensity, ecological importance, genetic uniqueness, and the feasibility of recovery actions.

Biodiversity loss affects both ecosystems and human societies.

Ecological consequences:

• Disruption of food webs and nutrient cycles.
• Reduced pollination, seed dispersal, and soil fertility.
• Greater vulnerability to pests, diseases, invasive species, and climate change.
• Loss of ecosystem resilience and reduced productivity.
• Extinction of species and erosion of genetic diversity.

Economic consequences:

• Decline in crop production, fisheries, forestry, and livestock improvement.
• Loss of medicinal and industrial resources.
• Reduced tourism and recreation income.
• Increased costs for water purification, flood control, and soil restoration.
• Greater risks to the livelihoods of forest-dependent and coastal communities.

Therefore, biodiversity conservation is an ecological necessity as well as an economic investment.