GS Notes

5. New Environment Notes 03

22 min read

Elaborate Notes

Functions in Ecosystem

  • Biotic Interaction Biotic interaction refers to the complex web of relationships and effects that organisms in an ecosystem have on one another. These interactions are the driving force behind natural selection and are fundamental to ecosystem dynamics and structure. They can be classified based on the nature of the interaction (e.g., competition, predation, mutualism, commensalism, parasitism) and are integral to the flow of energy and the cycling of nutrients within the ecosystem. The subsequent classification of organisms based on their feeding habits (trophic levels) and ecological roles are manifestations of these intricate biotic interactions.

  • Types of Organisms in Ecosystem (Based on Trophic Levels/Feeding Habits) These classifications are based on the organism’s primary source of nutrition, which determines its position in a food chain or food web. This hierarchy of feeding is known as the trophic structure.

    • (a) Producers (Autotrophs): These are organisms that produce their own food, typically through photosynthesis. They form the first trophic level and are the foundation of almost all ecosystems. They convert inorganic substances (like carbon dioxide and water) and a primary energy source (like sunlight) into organic compounds (like glucose).

      • Historical Context: The concept of photosynthesis was first elucidated through the work of scientists like Jan Ingenhousz in the late 18th century, who discovered that light was essential for plants to produce oxygen.
      • Examples: Terrestrial ecosystems are dominated by plants. In aquatic ecosystems, the primary producers are phytoplankton—microscopic marine algae—and cyanobacteria, which are responsible for a significant portion of the Earth’s oxygen production.

    • (b) Herbivores (Primary Consumers): These organisms feed directly on producers. They occupy the second trophic level. Their role is crucial in transferring energy from producers to higher trophic levels.

      • Examples: In a terrestrial ecosystem, examples include cows, goats, deer, and elephants. In an aquatic ecosystem, zooplankton that feed on phytoplankton are primary consumers.

    • (c) Carnivores (Secondary, Tertiary, etc., Consumers): These organisms feed on other animals. Secondary consumers feed on herbivores, while tertiary consumers feed on other carnivores. They occupy the third and higher trophic levels.

      • Examples: A lion hunting a zebra is a secondary consumer. An eagle that eats a snake which ate a frog is a tertiary consumer. Wolves, sharks, and spiders are other examples.

    • (d) Detritivores/Scavengers (Decomposers): These organisms play a vital role in nutrient cycling.

      • Detritivores: They feed on detritus, which is dead organic material such as fallen leaves, dead bodies of organisms, and fecal matter. They break down this material internally. Examples include earthworms, millipedes, and woodlice.
      • Scavengers: These are animals that consume carcasses of other animals that have died or been killed by other predators. They are crucial for cleaning the ecosystem. Examples include hyenas, vultures, and jackals.

    • (e) Nectarivores: These are animals that have evolved to feed on the sugar-rich nectar produced by flowering plants. This is often a mutualistic relationship, as the animal helps in pollinating the plant.

      • Examples: Hummingbirds, sunbirds, honey possums, and many insects like bees and butterflies.

    • (f) Frugivores: These organisms primarily feed on fruits. They are essential for seed dispersal, as they often excrete the seeds far from the parent plant, aiding in forest regeneration.

      • Examples: The Great Hornbill is a key frugivore in the forests of Northeast India and Southeast Asia, crucial for dispersing seeds of large-fruited trees. Other examples include parrots, parakeets, monkeys, and fruit bats.

    • (g) Graminivores: This is a specific type of herbivory where organisms feed predominantly on grasses (plants of the family Poaceae).

      • Examples: Many large grazing mammals like cows, horses, Indian Bison (Gaur), rhinoceroses, and elephants are graminivores. Birds like sparrows, munias, and bluethroats also consume grass seeds.

  • Types of Organisms Based on Ecological Roles This classification goes beyond feeding habits to describe the specific functional impact an organism has on its ecosystem.

    • (a) Flagship Species: This is a concept rooted in conservation marketing and strategy. A flagship species is chosen to represent a conservation cause, such as an ecosystem or an environmental issue. The choice is based on its charismatic appeal, cultural significance, or public recognition, making it an effective ambassador for generating awareness and financial support.

      • Historical Context: The practice was popularized by conservation NGOs like the World Wildlife Fund (WWF), which has used the Giant Panda as its logo since its founding in 1961.
      • Examples: The Bengal Tiger is used to champion the conservation of forest ecosystems in India. The Great Indian Bustard, a critically endangered and the heaviest flying bird, is a flagship species for the conservation of arid and semi-arid grasslands in India.
      • Note: The Sarus Crane is indeed the world’s tallest flying bird and serves as a flagship species for wetland conservation, particularly in the Indo-Gangetic plains.

    • (b) Keystone Species: The term was coined by zoologist Robert T. Paine in 1969. A keystone species is one whose impact on its ecosystem is disproportionately large relative to its abundance. Its removal can trigger a cascade of negative effects, leading to a dramatic shift in the ecosystem’s structure and function (a phenomenon called a trophic cascade).

      • Historical Context/Example: Paine’s research (1966, 1969) on the rocky intertidal shores of Washington, USA, showed that removing the predator starfish Pisaster ochraceus led to the collapse of the ecosystem, as its primary prey, mussels, outcompeted and eliminated other species. The reintroduction of gray wolves to Yellowstone National Park (established 1872, world’s first national park) in 1995 is a classic example. The wolves controlled the elk population, which had overgrazed willow and aspen. The recovery of these plants stabilized riverbanks and provided habitats for beavers and songbirds, demonstrating a widespread trophic cascade.
      • Other Examples: Honey bees are keystone species due to their critical role in pollination. Elephants are considered “ecosystem engineers” because they modify their habitat by uprooting trees, creating clearings, and digging waterholes, which benefits numerous other species.

    • (c) Indicator Species: An indicator species is an organism whose presence, absence, or abundance reflects a specific environmental condition. They serve as an early warning system for environmental changes or degradation.

      • Scientific Application: Ecologists use indicator species for biomonitoring. The presence of certain lichen species indicates low air pollution (especially sulfur dioxide), while their absence suggests poor air quality.
      • Examples: River Dolphins (like the Ganges River Dolphin) are indicators of the health of a river ecosystem; their declining numbers point to high levels of water pollution and habitat fragmentation. Corals are sensitive to water temperature, pH, and sedimentation, making them indicators of marine ecosystem health and climate change impacts. Blackbucks indicate the health of Indian grasslands. The Himalayan Monal, a pheasant, indicates the health and integrity of the Himalayan alpine and sub-alpine ecosystems.

    • (d) Umbrella Species: These are species that require large areas of habitat to survive. Conservation efforts focused on protecting umbrella species indirectly lead to the protection of a large number of other species that share the same habitat. The “umbrella” of protection covers the entire ecosystem.

      • Conservation Strategy: This is a pragmatic approach in conservation biology, where protecting a single, wide-ranging species can be more efficient than trying to manage every species individually.
      • Examples: Top predators like the tiger and the snow leopard are classic umbrella species because their home ranges are vast. Conserving a viable tiger population requires protecting large forest tracts, which in turn protects all the other flora and fauna within that forest. In marine environments, corals and kelp forests act as umbrella species as their physical structures create complex habitats that support thousands of other organisms.

  • Ecosystem Services The concept was popularized and systemically classified by the Millennium Ecosystem Assessment (MEA), a UN-sponsored initiative concluded in 2005. It refers to the many and varied benefits that humans freely gain from the natural environment and from properly-functioning ecosystems.

    • (a) Provisioning Services: These are the tangible products obtained from ecosystems.

      • Examples: Food (crops, livestock, fish), fresh water, fiber (timber, cotton, jute), biofuels, genetic resources, and minerals.

    • (b) Regulating Services: These are the benefits obtained from the regulation of ecosystem processes. They are often less visible but fundamentally crucial for human well-being.

      • Examples: Climate regulation (through carbon sequestration by forests and oceans), air quality regulation, water purification, flood prevention (by wetlands and forests), erosion control, pollination, and disease regulation.

    • (c) Cultural Services: These are the non-material benefits people obtain from ecosystems. They are deeply linked to human societies, traditions, and psychological well-being.

      • Examples: Spiritual and religious values (sacred groves), aesthetic appreciation (landscape beauty), opportunities for recreation and ecotourism, and educational and scientific inspiration.

    • (d) Supporting Services: These are the services that are necessary for the production of all other ecosystem services. They are the foundational processes of ecosystems.

      • Examples: Nutrient cycling (like the carbon and nitrogen cycles), soil formation, primary production (photosynthesis), and maintenance of biodiversity.

Biogeochemical Cycles

A biogeochemical cycle is the pathway by which a chemical substance moves through both biotic (biosphere) and abiotic (lithosphere, atmosphere, and hydrosphere) components of Earth. These cycles are essential for life as they recycle elements required by organisms.

  • Classification:
    • (a) Gaseous Cycle: The reservoir pool (the main stock of the element) is the atmosphere or the hydrosphere. These cycles tend to be relatively rapid. Examples include the Carbon, Nitrogen, Water, and Oxygen cycles.
    • (b) Sedimentary Cycle: The primary reservoir is the Earth’s crust (lithosphere). Elements are released from rocks by weathering and are then taken up by organisms. These cycles are generally much slower than gaseous cycles. Examples include the Sulphur and Phosphorous cycles.

Water Cycle (Hydrological Cycle)

This cycle describes the continuous movement of water on, above, and below the surface of the Earth.

  1. Evaporation & Transpiration: Solar energy heats surface water, causing it to evaporate and turn into water vapor. Plants also release water vapor from their leaves in a process called transpiration.
  2. Condensation: As the warm, moist air rises, it cools. The water vapor condenses into tiny water droplets or ice crystals. This condensation occurs around microscopic particles in the air known as cloud condensation nuclei or hygroscopic particles (e.g., dust, salt). This process leads to cloud formation.
  3. Precipitation: When the water droplets in clouds grow large enough, they fall back to Earth’s surface as precipitation (e.g., rain, snow, sleet, hail).
  4. Collection & Runoff: The precipitation is collected in water bodies (oceans, lakes, rivers) or soaks into the ground (infiltration), becoming groundwater. Water that flows over the land surface is called runoff.
  5. Condensation at Ground Level: When water vapor condenses near the ground, it can form dew (on surfaces), frost (if the temperature is below freezing), fog (a cloud at ground level with visibility less than 1 km), or mist (less dense than fog).

Carbon Cycle

This cycle describes the movement of carbon atoms between the atmosphere, oceans, land, and living organisms.

  1. Atmospheric Carbon: Carbon exists in the atmosphere primarily as carbon dioxide (CO₂).
  2. Photosynthesis: Plants, algae, and cyanobacteria absorb atmospheric CO₂ and, using sunlight, convert it into organic compounds (carbohydrates) for energy. The chemical equation is: 6CO₂ + 6H₂O + Sunlight → C₆H₁₂O₆ + 6O₂. This process ‘fixes’ carbon in the biosphere.
  3. Consumption: Animals (consumers) obtain carbon by eating plants or other animals.
  4. Respiration: All living organisms, including plants and animals, perform respiration, a process that breaks down organic compounds to release energy, releasing CO₂ back into the atmosphere.
  5. Decomposition: When organisms die, decomposers (bacteria and fungi) break down their organic matter. This process releases carbon into the soil and atmosphere.
  6. Fossil Fuel Formation: Over millions of years, some dead organic matter is not fully decomposed and gets buried under layers of sediment. Under heat and pressure, it transforms into fossil fuels (coal, oil, natural gas).
  7. Combustion: The burning of fossil fuels, as well as biomass (like wood), by humans for energy—an anthropogenic process—releases vast amounts of stored carbon into the atmosphere as CO₂.
  8. Ocean-Atmosphere Exchange: The oceans are a massive carbon sink. CO₂ from the atmosphere dissolves in ocean water. Marine organisms use it for photosynthesis or to build shells (calcium carbonate). While oceans absorb significant CO₂, they can also release it back into the atmosphere, especially as water temperature rises.

Oxygen Cycle

The oxygen cycle is intrinsically linked to the carbon cycle.

  1. Photosynthesis: This is the primary source of atmospheric oxygen. As shown in the equation above, plants release oxygen as a byproduct of converting CO₂ and water into glucose.
  2. Respiration: Most living organisms use oxygen for aerobic respiration to break down food and release energy, producing CO₂ as a waste product.
  3. Decomposition: Decomposers also consume oxygen during the process of breaking down dead organic matter.
  4. Oxidation/Weathering: Oxygen reacts with elements in the Earth’s crust, such as iron, to form oxides (e.g., rust). This chemical weathering process removes oxygen from the atmosphere.
  5. Photolysis: In the upper atmosphere, high-energy ultraviolet radiation from the sun can break down water molecules (H₂O) into hydrogen and oxygen.

Nitrogen Cycle

This cycle describes the conversion of nitrogen into various chemical forms as it circulates among the atmosphere, terrestrial, and marine ecosystems. Atmospheric nitrogen (N₂) is abundant (about 78%) but is inert and unusable by most organisms.

  1. Nitrogen Fixation: The conversion of atmospheric nitrogen (N₂) into ammonia (NH₃) or related nitrogenous compounds.

    • Biological Fixation: Carried out by specialized microorganisms.
      • Free-living bacteria: Azotobacter and Clostridium in the soil.
      • Symbiotic microbes: Rhizobium bacteria live in the root nodules of leguminous plants (like peas and beans). Cyanobacteria (Blue-Green Algae) such as Anabaena and Nostoc (Spirulina is a type of cyanobacterium but is more known for its nutritional value) also fix nitrogen.
    • Atmospheric Fixation: The immense energy of lightning breaks nitrogen molecules, allowing them to combine with oxygen to form nitrogen oxides, which dissolve in rain to form nitrates.
    • Industrial Fixation: The Haber-Bosch process, developed in the early 20th century, combines atmospheric nitrogen and hydrogen under high temperature and pressure to produce ammonia for fertilizers.

  2. Nitrification: The conversion of ammonia to nitrites and then to nitrates, which are the forms most usable by plants. This is a two-step process carried out by different bacteria.

    • Nitrosomonas bacteria convert ammonia (NH₃) into nitrites (NO₂⁻).
    • Nitrobacter bacteria convert nitrites (NO₂⁻) into nitrates (NO₃⁻).

  3. Assimilation: Plants absorb nitrates from the soil through their roots and incorporate them into proteins and nucleic acids. Animals then get nitrogen by eating plants.

  4. Ammonification: When organisms die, decomposers (bacteria and fungi) convert the organic nitrogen back into ammonia (NH₃). This process returns nitrogen to the soil.

  5. Denitrification: The conversion of nitrates (NO₃⁻) back into gaseous nitrogen (N₂), which is released into the atmosphere. This process is carried out by denitrifying bacteria like Pseudomonas under anaerobic (low-oxygen) conditions, completing the cycle.

  6. Anthropogenic Impact: The combustion of fossil fuels releases nitrogen oxides (NOx) into the atmosphere, contributing to acid rain (in the form of nitric acid) and smog.

Phosphorus Cycle

This is a sedimentary cycle, meaning it has no significant atmospheric component.

  1. Reservoir: The main reservoir of phosphorus is in rocks and marine sediments in the form of phosphate ions (PO₄³⁻).
  2. Weathering: The slow process of weathering and erosion of these rocks releases phosphates into the soil and water.
  3. Assimilation by Plants: Plants absorb dissolved phosphates from the soil and incorporate them into organic molecules like DNA, RNA, and ATP.
  4. Consumption: Animals obtain phosphorus by eating plants or other animals.
  5. Decomposition: When plants and animals die, decomposers break down their organic matter, returning phosphates to the soil and water through excretion and decomposition. This is a relatively fast part of the cycle.
  6. Sedimentation & Lithification: Phosphates from the soil can be leached into water bodies by rain and rivers. In aquatic environments, much of this phosphorus settles to the bottom, becomes part of the sediment, and over geological time, is compressed and uplifted to form new rock (lithification), thus closing the long-term cycle.

Sulphur Cycle

This is a sedimentary cycle, but it has a significant atmospheric component, making it a hybrid cycle.

  1. Reservoir: The main reservoir of sulphur is in the lithosphere. It is stored in rocks and sediments in inorganic forms as sulfate (SO₄²⁻) and sulfide (FeS₂) minerals. In organic forms, it is found in fossil fuels like coal, petroleum, and peat.
  2. Release: Sulphur is released into the environment through:
    • Weathering of rocks.
    • Volcanic eruptions, which release sulfur dioxide (SO₂) and hydrogen sulfide (H₂S).
    • Decomposition of organic matter by microbes.
    • Anthropogenic sources, primarily the combustion of fossil fuels and industrial processes like smelting, which release large amounts of SO₂.
  3. Atmospheric Processes: In the atmosphere, SO₂ reacts with oxygen and water to form sulfuric acid (H₂SO₄), a major component of acid rain. These sulfate particles can then be deposited back on Earth through wet (rain, snow) and dry deposition.
  4. Assimilation: Plants absorb sulfate ions from the soil and incorporate them into proteins. Animals get sulphur by consuming plants.
  5. Decomposition: Decomposers release sulphur from dead organic matter, often in the form of hydrogen sulfide (H₂S). Specialized bacteria can then convert this back into sulfates, making it available for plants again.

Tigers

  • IUCN Red List Categories: The International Union for Conservation of Nature (IUCN) maintains a Red List of Threatened Species, which classifies species based on their risk of extinction. The categories are: Not Evaluated (NE), Data Deficient (DD), Least Concern (LC), Near Threatened (NT), Vulnerable (VU), Endangered (EN), Critically Endangered (CR), Extinct in the Wild (EW), and Extinct (EX).

  • Big Cats in India: India is home to five species of big cats:

    1. Lion (Panthera leo) - specifically the Asiatic Lion, found only in Gujarat.
    2. Tiger (Panthera tigris) - the Bengal subspecies.
    3. Leopard (Panthera pardus).
    4. Snow Leopard (Panthera uncia).
    5. Cheetah (Acinonyx jubatus) - The Asiatic Cheetah was declared extinct in India in 1952. An African Cheetah reintroduction project was initiated in 2022.
    • Note: The Jaguar (Panthera onca) and Puma (Puma concolor) are native to the Americas and are not found in India.

  • Tiger Conservation Status and Details:

    • IUCN Status: The tiger as a species is listed as Endangered (EN) on the IUCN Red List.
    • CITES Status: It is listed in Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which means international commercial trade in tigers or their body parts is prohibited.
    • Tiger-Range Countries (TRCs): There are 13 countries where tigers are still found in the wild: India, Nepal, Bhutan, Bangladesh, Myanmar, Thailand, Malaysia, Indonesia, Cambodia, Laos, Vietnam, China, and Russia.
    • Global Tiger Population: India is the global leader in tiger conservation, hosting over 70% of the world’s wild tiger population. The “Status of Tigers in India, 2022” report estimated the population at 3,682.
    • Subspecies: Tiger subspecies are often grouped into continental and island populations.
      • Continental Tigers:
        • Royal Bengal Tiger (Panthera tigris tigris): Found in India, Nepal, Bhutan, Bangladesh.
        • Indo-Chinese Tiger (Panthera tigris corbetti): Found in Southeast Asia.
        • Malayan Tiger (Panthera tigris jacksoni): Found in the Malay Peninsula.
        • Amur/Siberian Tiger (Panthera tigris altaica): Found in the Russian Far East and Northeast China. It is the largest of all tiger subspecies.
        • South-China Tiger (Panthera tigris amoyensis): Considered functionally extinct in the wild.
      • Island Tigers:
        • Sumatran Tiger (Panthera tigris sumatrae): Found only on the island of Sumatra, Indonesia. Critically Endangered.
        • Javan Tiger (Panthera tigris sondaica): Formerly on the island of Java. Declared extinct.
        • Bali Tiger (Panthera tigris balica): Formerly on the island of Bali. Declared extinct.
    • Ecological Importance: The tiger is the largest of all big cat species. It holds immense ecological significance as it is simultaneously a:
      • Keystone Species: As a top predator, it regulates the populations of herbivores, preventing overgrazing and maintaining the health of the forest vegetation.
      • Umbrella Species: Protecting tigers requires conserving vast tracts of forest habitat, which in turn protects countless other species within that ecosystem.
      • Flagship Species: Its charismatic nature makes it a powerful symbol for conservation, attracting global attention and funding.

Prelims Pointers

  • Producers: Organisms capable of photosynthesis (e.g., plants, phytoplankton).
  • Herbivores: Plant-eating organisms (e.g., cow, goat, deer).
  • Carnivores: Feed on other animals (e.g., lion, wolf, shark).
  • Detritivores/Scavengers: Feed on dead organic matter (e.g., earthworms, vultures, hyenas).
  • Nectarivores: Feed on nectar (e.g., hummingbird, bees).
  • Frugivores: Fruit-eating organisms (e.g., parrots, monkeys, hornbills).
  • Graminivores: Grass-eating organisms (e.g., cow, horse, elephant, rhinoceros).
  • Flagship Species: A charismatic species used as an ambassador for a conservation cause (e.g., Tiger, Giant Panda).
  • Keystone Species: A species with a disproportionately large effect on its ecosystem (e.g., Wolves in Yellowstone, Sea Otters, Elephants).
  • Indicator Species: A species whose status provides information on the overall health of the ecosystem (e.g., Lichens for air pollution, River Dolphins for water pollution, Corals for marine health).
  • Umbrella Species: A wide-ranging species whose protection indirectly protects many other species in its habitat (e.g., Tiger, Snow Leopard).
  • Ecosystem Engineers: Organisms that create, modify, or maintain habitats (e.g., Elephants, Beavers).
  • World’s First National Park: Yellowstone National Park, USA (established in 1872).
  • Tallest Flying Bird: Sarus Crane.
  • Heaviest Flying Bird: Great Indian Bustard.
  • Ecosystem Services: Classified into four types: Provisioning, Regulating, Cultural, and Supporting.
  • Biogeochemical Cycles Reservoir:
    1. Gaseous Cycles: Reservoir is the atmosphere or hydrosphere (e.g., Carbon, Nitrogen, Oxygen, Water).
    2. Sedimentary Cycles: Reservoir is the Earth’s crust/lithosphere (e.g., Phosphorus, Sulphur).
  • Nitrogen Cycle Bacteria:
    1. Nitrogen Fixation: Azotobacter, Clostridium (free-living); Rhizobium (symbiotic).
    2. Nitrification: Nitrosomonas (ammonia to nitrite); Nitrobacter (nitrite to nitrate).
    3. Denitrification: Pseudomonas.
  • Phosphorus Cycle: Does not have a significant gaseous or atmospheric phase.
  • Big Cats in India: Lion, Tiger, Leopard, Snow Leopard, and Cheetah (reintroduced).
  • Big Cats NOT in India: Jaguar and Puma.
  • Tiger (Panthera tigris) Status:
    • IUCN Red List: Endangered.
    • CITES: Appendix I.
  • Tiger-Range Countries: Total 13 countries including India, Nepal, Russia, and Indonesia.
  • Largest Tiger Subspecies: Amur or Siberian Tiger.
  • Extinct Tiger Subspecies: Bali Tiger, Javan Tiger.

Mains Insights

GS Paper I: Geography and Indian Society

  • Cultural Ecosystem Services and Society: The concept of cultural services highlights the deep connection between ecosystems and human societies. In India, this is exemplified by ‘Sacred Groves’, which are patches of forest protected by local communities due to religious beliefs. This traditional conservation practice preserves biodiversity and represents a non-material, spiritual service provided by the ecosystem. The degradation of such ecosystems can lead to a loss of cultural identity and traditional knowledge.
  • Biogeochemical Cycles and Geomorphology: The water cycle is a fundamental driver of geomorphological processes like erosion and deposition, shaping landscapes through the actions of rivers and glaciers. Similarly, the slow weathering process in the phosphorus and sulphur cycles contributes to soil formation and the chemical composition of the Earth’s crust over geological time scales.

GS Paper III: Environment, Biodiversity, and Economy

  1. Conservation Models and Species Roles:

    • Cause-Effect (Keystone Species): The removal of a keystone species triggers a ‘trophic cascade’. For instance, the elimination of tigers (a top predator) can lead to an unchecked increase in herbivore populations (like deer), resulting in overgrazing. This overgrazing degrades forest undergrowth, affects soil quality, impacts other smaller herbivores, and ultimately reduces the forest’s biodiversity and resilience. This demonstrates that single-species conservation (especially of a keystone species) is crucial for ecosystem-wide stability.
    • Debate (Pragmatism in Conservation): The concepts of flagship, keystone, and umbrella species represent different strategies in conservation. While a flagship species (like the panda) is good for fundraising, it may not be ecologically the most crucial. An umbrella species approach (like conserving tigers) is efficient as it protects entire habitats. A keystone species approach is critical for functional integrity. A balanced conservation policy must judiciously use all three approaches based on specific ecological and social contexts.

  2. Ecosystem Services: Valuation and Integration into Policy:

    • Valuation Debate: There is an ongoing debate on the economic valuation of ecosystem services. Proponents, like economist Robert Costanza, argue that assigning a monetary value can help policymakers recognize their importance and incorporate them into national accounts (e.g., Green GDP). Critics argue that it is ethically problematic to commodify nature and that many cultural and supporting services are priceless and cannot be captured in monetary terms.
    • Cause-Effect (Degradation and Disasters): The degradation of regulating services has direct economic and social consequences. For example, the destruction of coastal mangroves (which provide flood prevention services) has been directly linked to increased damage and loss of life during tsunamis (e.g., the 2004 Indian Ocean tsunami) and cyclones. This establishes a clear cause-effect link between environmental degradation and increased vulnerability to natural disasters.

  3. Anthropogenic Disruption of Biogeochemical Cycles:

    • Carbon Cycle Disruption: The massive release of carbon from burning fossil fuels has overwhelmed the natural sequestration capacity of forests and oceans, leading to global warming and climate change. This necessitates global policy responses like the Paris Agreement under the UNFCCC.
    • Nitrogen and Phosphorus Cycle Disruption: The industrial production of fertilizers (Haber-Bosch process) and agricultural runoff have drastically altered the nitrogen and phosphorus cycles. Excess nutrients in water bodies lead to eutrophication—algal blooms that deplete oxygen, creating ‘dead zones’ and causing a collapse of aquatic ecosystems. This highlights the need for policies promoting sustainable agriculture and better wastewater management.

  4. Tiger Conservation as a Development Challenge:

    • Successes and Challenges of Project Tiger (1973): Project Tiger has been a globally acclaimed success, increasing the tiger population significantly. However, its success has created new challenges. The ‘fortress conservation’ model, which creates inviolate core areas, has often led to the displacement of forest-dwelling communities, raising human rights concerns.
    • Human-Wildlife Conflict: As tiger populations recover and expand their territories, they increasingly come into conflict with human populations living on the peripheries of protected areas, leading to livestock predation and human casualties. An effective conservation strategy must include robust mechanisms for conflict mitigation, community participation, and providing alternative livelihoods to reduce dependency on forest resources.
    • Economic Dimension: Tiger tourism is a significant source of revenue, but it must be managed sustainably to avoid ecological damage (‘tourism carrying capacity’) and ensure that economic benefits flow to local communities, making them stakeholders in conservation.

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