Topics to be Learn :

  • Introduction
  • Levels of biodiversity
  • Patterns of biodiversity
  • Biodiversity current scenario
  • Loss of biodiversity
  • Conservation and biodiversity
  • Biological Diversity Act 2002
  • Environmental  issues
  • Greenhouse effect and global warming
  • Ozone depletion
  • Deforestation
  • Mission Harit Maharashtra

Diversity Summary: Diversity is variety.

Biodiversity:

  • Definition: Variety of life on Earth, including microorganisms, viruses, algae, fungi, plants, and animals in different habitats.
  • Diversity seen in shape, color, form, nutrition, habitats, reproduction, motility, life cycle, lifespan, etc.
  • Coined by Walter Rosen, popularized by Edward Wilson.
  • Definition: Differences in genes, species, and ecosystems within defined areas.
  • Result of over 3.5 billion years of evolution, influenced by natural and human processes.

Levels of Biodiversity:
  • Various Levels: Diversity seen from molecular to ecosystem levels.

  1. Genetic Diversity:

    • Also known as intraspecific diversity.
    • Diversity in genes and chromosomes among species.
    • Variations in alleles within species.
    • Essential for healthy breeding populations.
    • Genetic variations lead to individual differences and aid evolution.
    • Races and subspecies formed due to genetic diversity.
    • Examples:
      • 1000 varieties of mangoes, 50,000 varieties of rice or wheat in India.
      • Variations in potency and concentration of reserpine in Rauwolfia vomitoria.

  2. Species Diversity:

    • Also called interspecific diversity.
    • Diversity in the number of plant and animal species in a region.
    • Expressed as species richness and evenness.
    • Species diversity higher in Western Ghats than Eastern Ghats.
    • Natural forests richer in species than timber plantations.

  3. Ecological or Ecosystem Diversity:

    • Diversity of ecosystems and habitats in a given area.
    • One or many different types of ecosystems.
    • High in India, low in Norway.
    • India has various ecosystems like grasslands, estuaries, rain forests, and deserts.
    • Western Ghats show significant ecosystem diversity.
    • Ladakh and the Rann of Kutch have lower ecosystem diversity.

Patterns of Biodiversity:

  1. Latitudinal Species Diversity:

    • Greater species richness at lower latitudes, declining towards poles.
    • Called distribution of diversity along latitudes.
    • Factors:
      • Overall stability of tropical regions.
      • Lesser annual climatic changes.
      • Plenty of sunlight.
      • Lesser drastic disturbances like glaciations.
      • Reduced gene flow due to lesser migrations.
      • Normal temperature and higher annual rainfall.

  2. Altitudinal Species Diversity:

    • More diversity at lower altitudes, decreases at higher altitudes.
    • Due to change in climatic conditions and drastic seasonal variations.

  3. Species-Area Relationship:

    • Number of species proportional to area size.
    • Observed by Alexander von Humboldt.
    • Observations by Humboldt:
      • Species richness increases with area up to a limit.
      • Relationship often a rectangular hyperbola.
      • Equation: log S = log C + Z log A.
       
    • Explanation:
      • Larger areas have more resources for species.
      • For smaller areas, Z ranges from 0.1 to 0.2.
      • Larger areas show steeper slopes, indicating faster increase in species count.
      • In very large areas, number of species increase faster than explored area. 
    Importance of Species Diversity to the Ecosystem:

  1. Stability of Community:

    • Stable community has constant biomass production.
    • Withstands disturbance, recovers quickly, resists invasive species.

  2. Productivity Stability Hypothesis (David Tillman):

    • Rich diversity leads to less variation in biomass production over time.

  3. Rivet Popper Hypothesis (Paul Ehrlich):

    • Relationship between diversity and ecosystem wellbeing.
    • Loss of key species threatens ecosystem balance rapidly.
    • Affects food chain, food web, energy flow, and natural cycles.

Biodiversity Current Scenario:

  • IUCN data (2004): Over 1.5 million documented species, many more unstudied.
  • Majority of temperate species researched, but tropical species not.
  • Robert May estimates 7 million species on the planet.
  • India holds 8.1% of world's biodiversity.
  • India is one of 12 nations with greatest diversity.
  • India has around 45,000 plant and 90,000 animal species.
  • Rapid deforestation and reforestation threaten undocumented species.

Loss of Biodiversity:
  • Imbalance in ecosystem if biodiversity is lost.
  • Three types of extinctions:
    • Natural extinction: Forest fires, earthquakes.
    • Mass extinction: Major loss of species.
    • Anthropogenic extinction: Habitat destruction, hunting, overexploitation.
  • Five mass extinctions in Earth's history.
  • Sixth extinction happening now, 100 to 1000 times faster than pre-human times.
  • 50% of diversity lost, altering environmental processes.
Causes of Biodiversity Loss: Four major causes, known as Evil Quartet:
(i) Habitat Loss and Fragmentation:
  • Primary factor destroying biodiversity.
  • Large natural habitats disappearing due to pollution and degradation.
  • Human activity largely responsible.
  • Endangers local organisms, migratory birds, and animals.
  • Tropical rainforest reduction from 14% to 6%, leading to species extinction.
(ii) Overexploitation:
  • Humans using natural resources excessively.
  • Overuse due to consumption and accumulation.
  • Threatens various organisms.
  • Examples: dodo bird, stellar sea cow, passenger pigeon extinct due to overexploitation.
  • Overfishing in the sea leading to fish scarcity.
(iii) Alien Species Invasion:
  • Introduction of invasive species causing extinction of local species.
  • Examples: Carrot grass (Parthenium), Lantana, Water hyacinth (Eichhornia).
  • Example of invasive animal: African catfish Clarias gariepinus, harming endemic catfish varieties.
  • Major reason for extinction of local species.
(iv) Co-extinctions:
  • When two organisms are obligately linked, extinction of one leads to extinction of the other.
  • Co-extinction occurs.
  • Unique parasites perish with their hosts.
  • Coevolved plant-pollinator faces threat.

Extinct Species: Totally eliminated from Earth. E.g., Dinosaurs.
Endangered Species:
  • Species with dwindling numbers.
  • Monitored by IUCN through Red List.
Categories According to IUCN:

  1. Extinct (EX):

    Final member passed away or existence unverified.

  2. Extinct in the Wild (EW):

    Species only existing in captivity.

  3. Critically Endangered (CR):

    Extremely high risk of extinction.
    • Very few surviving members (≤ 50).

  4. Endangered (EN):

    Very high risk of extinction.
    • Rapid population decline (50-70% over 10 years).

  5. Vulnerable (VU):

    Very high risk of extinction.
    • Rapid population decline (30-50% over 10 years).

  6. Near Threatened (NT):

    • Close to becoming threatened. May meet threatened status criteria soon.

  7. Least Concern (LC):

    Pervasive and abundant species after assessment.

  8. Data Deficient (DD):

    Insufficient data related to extinction risk.

  9. Not Evaluated (NE):

    Species not assessed by IUCN.
Conservation and Biodiversity:

Definition: Protection, upliftment, and scientific management of biodiversity to maintain an optimum level and sustainable benefits.

Reasons for Conservation:

  1. Utilitarian Reasons:

    • Narrowly Utilitarian Reasons:
      • Humans benefit from biodiversity for food, clothing, shelter, industrial products, aesthetics, ornaments, artifacts, and medicines.
      • Industrial products like resins, tannins, and perfumes obtained from biodiversity.
      • Ornaments and artifacts made from biodiversity.
      • Many medicines derived from biodiversity, contributing 25% to global medicine market.
      • Around 25,000 species used for traditional medicines by tribal populations worldwide.
      • Bioprospecting for economically important species.
    • Broadly Utilitarian Reasons:
      • Biodiversity provides oxygen, seed dispersal, pollination, and other free services.
      • All green plants produce oxygen, essential for human survival.
      • Amazon forest alone provides 25% of the world's oxygen.
      • Insects aid in pollination and seed dispersal.
      • Without pollination and seed dispersal, humans would suffer food shortages.
      • Biodiversity also crucial for human recreation.
    • Considering these, conservation of biodiversity is essential.

  2. Ethical Reasons:

    • Humans share Earth with diverse life forms, all with equal right to survive.
    • Ethically, species should not be eliminated for prospective economic use.
Conservation of Biodiversity:

In Situ Conservation:

  • Preservation of organisms in their natural environment.
  • Onsite conservation.
  • Done in natural habitats like national parks, sanctuaries, biosphere reserves.
  • Dynamic process, cost-effective.
  • Preserves farming and horticultural varieties.
  • Captive breeding not always successful.
  • Examples: Western Ghats, Indo-Burma, Eastern Himalayas - world's biodiversity hotspots.
  • In India: 34 biodiversity hotspots, 14 biosphere reserves, 90 national parks, 448 wildlife sanctuaries.
  • Sacred groves: protected areas in the name of God, found in Meghalaya, Maharashtra, Karnataka, Rajasthan, Madhya Pradesh.
Ex-Situ Conservation:
  • Protection of critically endangered species in captivity.
  • Done outside natural habitat.
  • Species conserved in wildlife safari parks, zoological parks, botanical gardens.
  • Modern techniques: seed banks, tissue culture, cryopreservation.
  • Static process, expensive.
  • Successful captive breeding helps increase endangered organisms.

Biological Diversity Act 2002:
  • The Rio de Janeiro Earth Summit produced the Convention on Biological Diversity (CBD- 1992).
  • Indian government passed the Biological Diversity Act (BD Act) in 2002 in accordance with CBD.
  • Provides framework for managing and preserving nation's natural resources sustainably.
  • Broadly defines biodiversity including plants, animals, microorganisms, genetic materials, and by-products.
  • Excludes value-added goods and human genetic material.
Objectives:
  1. Regulation of Access to Indian Biological Resources.
  2. Scientific Cataloguing of Traditional Knowledge about Ethnobiological Materials.
Three-Tier System in India:

  1. National Biodiversity Authority (NBA):

    At national level.

  2. State Biodiversity Boards (SBBs):

    At state level.

  3. Biodiversity Management Committees (BMCs):

    At local level.

Environmental Issues:

Environment Protection Act 1986: Indian Government passed to protect and improve environment quality.

Reasons for Loss of Natural Resources:

  • Exponential human population growth.
  • Industrial development.
  • Uncontrolled exploitation of nature.
  • Utilization and production of synthetic materials.
  • Construction activities.
  • Resultant pollution.

Types of Pollution: Air pollution, Noise pollution, Water pollution, Radioactive pollution, Soil pollution.

Pollutant: Substance causing pollution.

Air Pollution:

  • Unfavorable alteration in air quality damaging respiratory system.
  • Severity depends on exposure duration, pollutant concentration, and organism type.
  • Affects crop yield, causes premature plant death.
  • Major cause: automobile traffic.

Types of Air Pollutants: Particulate and Gaseous pollutants.

Particulate Air Pollutants:

  • Solids or liquids.
  • Fine particles (<1 μm) remain suspended in air, causing harm.
  • PM 2.5 particles cause significant harm.
  • Examples: Smoke, smog, pesticides, heavy metals, dust, radioactive elements.

Gaseous Pollutants: CO, CO2, SO2, NO, NO2, etc.

  • Carbon Dioxide (CO2):

    • Greenhouse gas, excess produced by human activities like fossil fuel burning.
    • Natural balance disturbed, affects photosynthesis.
    • Aeroplane traffic emits CO2.

  • Carbon Monoxide (CO):

    • Produced by incomplete fuel combustion.
    • Toxic gas, vehicular exhausts major source.
 

Nitrogen Dioxide (NO2) and Nitrogen Monoxide (NO):

  • Released by automobiles and chemical industries.
  • NO2 forms nitric acid when combined with water vapors.
  • Causes irritation to eyes and lungs; at high concentrations, can damage lungs, liver, and kidneys.

Control Measures for Air Pollution:

(i) Electrostatic Precipitator:

  • Removes particulate matter (soot, dust) from industrial exhaust.
  • Capable of removing almost 99% of particulate matter.

Working:

  1. High voltage applied, producing electric discharge.
  2. Discharge ionizes air in smokestack, creating free electrons.
  3. Electrons attach to gaseous or dust particles.
  4. Negatively charged particles settle on positive electrode, collected in reservoir.

(ii) Exhaust Gas Scrubbers:

  • Clean air by removing both dust and gases.
  • Exhaust passed through dry or wet packing material.
  • Gases like SO2 removed, sometimes by passing through water or lime spray.

 
 (iii) Catalytic Converters:
  • Remove harmful gases like CO and nitrogen oxides from automobile exhausts.
  • Reduce harmful effects of air pollution.

 Working:

  1. Reduction Block:

    • Nitrogen oxides enter the reduction block of the catalyst.
    • Oxides of nitrogen react to form nitrogen and oxygen.

  2. Oxidation Block:

    • Exhaust gases enter the oxidation block of the catalyst.
    • Hydrocarbons and newly formed oxygen react to form carbon dioxide.

  3. Release Block:

    Least harmful gases are released.
Controlling Vehicular Air Pollution: A Case Study of Delhi:
  • In 1990, Delhi ranked fourth among the most polluted cities globally.
  • In response to Public Interest Litigation (PIL), Supreme Court of India ordered Delhi government to take actions.

Measures Taken:

  • Conversion of all city buses to CNG by 2002.
  • Introduction of new fuel policy, setting norms to reduce sulphur and aromatic content of petrol and diesel.
  • Engine upgradation.
  • Introduction of Bharat stage emission standards (equivalent to Euro norms).
  • Implementation of BS II to BS VI norms from 2001 to 2017.
  • Administrative measures such as closing educational institutions, suspending construction or demolition work, and vacuum cleaning of roads.
  • Penalties imposed on polluting industries; Badarpur thermal power plant temporarily closed down.
Noise Pollution:
  • Definition: Noise is considered an air pollutant causing psychological and physiological changes in humans.
  • Effects: Permanent hearing loss, sleeplessness, increased heartbeat, altered breathing, psychological stress, interference in learning.
  • Sources: Machines, transportation, construction sites, industries.

Ways to Reduce Noise Pollution:

  1. Noise Reduction in Industries:

    • Use of sound absorbent materials.
    • Muffling the noise.

  2. Enforcement of Laws:

    • Strict enforcement of laws prohibiting horn use in schools and hospitals.
    • Regulations on firecrackers and loudspeakers, with the use of loudspeakers prohibited after 10 p.m.
Water Pollution:
  • Causes: Mostly manmade.
  • Definition: Water with pathogens, heavy metals, and oils.
  • Impurities: Even a small amount (0.1%) of impurities makes water polluted.
  • Legislation: Water Prevention and Control of Pollution Act 1974 to safeguard water resources.
  • Sources: Domestic sewage and industrial effluents.

Domestic Sewage and Industrial Effluents:

  • Components: Dissolved salts, nutrients, toxic metal ions, organic compounds, harmful bacteria, and viruses.
  • BOD (Biochemical Oxygen Demand): Measure of biodegradable organic matter in polluted water, expressed in mg/L.
  • Algal Bloom: Excessive growth of blue-green algae, releasing toxins and causing fish death.
  • Water Hyacinth (Eichhornia crassipes): Invasive species causing nuisance by excessive growth in water bodies.

Types of Eutrophication:

  1. Natural Eutrophication:

    Ageing of a lake due to nutrient enrichment over a long period.

  2. Cultural or Accelerated Eutrophication:

    Pollutants from human activities cause accelerated ageing of water bodies.

Biological Magnification: Accumulation of pollutants in organisms and their increasing concentrations along the food chain. Examples: DDT and mercury.

Thermal Pollution:
  • Sources: Thermal and nuclear power plants using water as coolant.
  • Effects: Rise in water temperature causing loss of flora and fauna sensitive to temperature.

Measures to Reduce Sewage Water:

  1. Ecosan:

    • Definition: Ecological sanitation (Ecosan) safely reuses excreta in agriculture as manure.
    • Benefits:
      • Reduces the need for chemical fertilizers.
      • Closed system without water, suitable for water-scarce areas.
      • Helps in recycling nutrients for agriculture.
      • Feces composted to organic manure over time.
    • Implementation: Implemented in Gujarat, Kerala, Tamil Nadu, and Sri Lanka.

  2. Reverse Osmosis (RO):

    • Definition: Sewage water reused after reverse osmosis treatment.
    • Benefits: Solves water scarcity and sewage treatment issues.

  3. Rainwater Harvesting (RWH):

    • Definition: Collection and storage of rainwater for later use.
    • Benefits: Addresses water scarcity, mandatory for new constructions.

Solid Waste Management:

  • Definition: Waste from homes, offices, stores, schools, hospitals, etc.
  • Municipal Wastes: Collected and disposed of by municipalities.
  • Methods: Burning: Reduces waste volume but causes air pollution.

Key Points:

  • Ecosan reuses human excreta as manure, reducing the need for chemical fertilizers.
  • RO treats sewage water for reuse, addressing water scarcity.
  • RWH collects rainwater to mitigate water scarcity, now mandatory for new constructions.
  • Burning solid waste reduces volume but causes air pollution.

Sanitary Landfills:

  • Waste is compacted and buried in trenches to prevent attraction of pests.
  • Despite being widely used, they are not foolproof.
  • Issues include increasing trash volume, seepage of dangerous chemicals, and pollution of underground water reserves.
  • Need for environmental awareness to reduce non-biodegradable waste.

Types of Solid Wastes:

  1. Biodegradable: Naturally decomposes, can be buried in pits.
  2. Recyclable: Should be given to kabadiwallahs and rag-pickers.
  3. Non-biodegradable: Should be reduced at the source; eco-friendly packaging advocated.

Biomedical Wastes:

  • Generated by hospitals; contain harmful chemicals and microorganisms.
  • Handled carefully, treated, and disposed of using incinerators.

Electronic Wastes (E-Wastes):

  • Materials like computers, mobile phones, CDs, batteries, etc.
  • Managed by burying in landfills or incineration.
  • In developing countries, metals are recovered through recycling.
  • Recycling exposes workers to toxic substances, should be done in an eco-friendly manner.

Anti-Plastic Notifications: Maharashtra government has banned plastic usage to create a "Plastic Free Maharashtra."

Greenhouse Effect:
  • Natural phenomenon that raises Earth's average temperature.
  • Earth's temperature would be -18 °C without it; currently averaging 15 °C.
  • Excessive greenhouse effect leads to global warming and climate change.
  • Atmospheric gases like carbon dioxide, methane, etc., trap infrared radiation, warming the Earth's surface.
  • Main greenhouse gases: carbon dioxide, methane, chlorofluorocarbons (CFCs), nitrous oxide (N2O), water vapour.

Global Warming:

  • Increase in Earth's temperature, mainly caused by greenhouse effect.
  • Earth's temperature has risen by 0.6 °C in the past century, most in the last three decades.
  • CO2 concentration increases temperature by retaining more heat.
  • Industrialization, atmospheric air pollution, and greenhouse effect contribute to global warming.
  • Effects include El Niño, melting polar ice caps, rising sea levels, coastal submergence.

Measures to Reduce Greenhouse Effect and Global Warming:

  1. Reducing fossil fuel use: Decreases CO2 emissions.
  2. Efficient energy use: Promotes solar or wind energy.
  3. Reducing deforestation: Preserves carbon sinks.
  4. Tree plantation and afforestation: Increases carbon absorption.
  5. Population control: Slows down carbon emissions.
  6. International initiatives: Agreements to reduce greenhouse gases.

El Niño and La Niña:

  • El Niño: Climate cycle in the Pacific Ocean with global weather impacts. Warm water shifts eastward along the equator towards the coast of America.
  • La Niña: Cooling of surface ocean waters along the tropical west coast of South America.

Ozone Depletion:

  • Ozone layer in the upper stratosphere absorbs ultraviolet radiation from the sun, protecting life on Earth.
  • Formed by action of ultraviolet radiation on molecular oxygen.
  • Ozone absorbs harmful UV radiation, preventing DNA and protein damage.
  • Measured in Dobson units (DU).
  • Disruption of ozone layer due to excessive chlorofluorocarbons (CFCs) in the atmosphere.
  • CFCs released from products like refrigerators reach the stratosphere, where UV rays release chlorine atoms, degrading ozone.
  • Results in ozone depletion or formation of ozone hole, especially over Antarctica.

Deleterious Effects of Ozone Depletion:

  1. Skin aging: UV radiation accelerates skin aging.
  2. Skin cancers: Damage to skin cells increases the risk of skin cancers.
  3. Eye damage: UV radiation causes inflammation and damage to the cornea, leading to snow-blindness and cataracts.
  4. DNA damage: UV-B radiation damages DNA, leading to mutations.

Montreal Protocol:

  • International treaty signed in 1987 in Montreal, Canada.
  • Aimed to control emissions of ozone-depleting substances.
  • Implemented in 1989, leading to a reduction in ozone depletion worldwide.

Deforestation:

  • Converting forested land into barren land.
  • Tropical forests reduced by about 40%, temperate forests by 1%.
  • India's forest cover decreased from 30% to 19.4% since early 20th century.
  • National Forest Policy (1988) recommends 67% forest cover in hilly areas and 33% in plains.

Causes:

  • Unplanned human activities.
  • Conversion to agriculture: For food production.
  • Timber and firewood extraction.
  • Infrastructure development: Dams, roads, etc.
  • Government policies: Encouraging development.
  • Slash and burn agriculture: Jhum cultivation.
  • Overpopulation leads to repeated cultivation.

Major Effects:

  • Increased CO2: Loss of carbon stored in trees.
  • Loss of biodiversity: Habitat destruction.
  • Hydrologic cycle disturbance.
  • Soil erosion and desertification.

Reforestation:

  • Restoring lost forests through natural or human efforts.
  • Human-led reforestation can cause loss of natural biodiversity.

People's Participation:

  • Saalumarada Thimmakka: Planted and tended to 385 banyan trees, honored with National Citizens Award and Padma Shri.
  • Moirangthem Loiya: Restored Punshilok forest over 17 years, containing over 250 plant species, including 25 varieties of bamboo.
 

Case Study: People's Participation in Forest Conservation

(1) Amrita Devi Bishnoi and the Bishnoi Community:

  • In 1731, Amrita Devi and Bishnoi community members sacrificed their lives to save trees.
  • Represents sacrificing lives for environmental conservation.
  • Amrita Devi Bishnoi Wildlife Protection Award instituted by the Government of India.

(2) Chipko Movement:

  • In 1974, Garhwal region of Himalayas.
  • People hug trees to protect them from being cut down.
  • Gained global recognition as a symbol of environmental activism.

(3) Joint Forest Management (JFM):

  • Introduced by the Indian Government in the 1980s.
  • Collaborates with local communities for forest protection and management.
  • Aims for sustainable forest conservation.

Mission Harit Maharashtra:

  • Started by the Maharashtra government in 2016 to plant 50 crore trees.
  • District-wise yearly plantation targets set, governed by the National Forest Policy.
  • 24-hour toll-free helpline (1926) for information and awareness.
  • Mobile app 'MY Plants' tracks plantation details.
  • Plantation figures: 2.87 crore (2016), 5.17 crore (2017), 15.17 crore (2018), 33 crore (2019).
  • Adoption of Japanese Miyawaki method in districts like Beed, Hingoli, Pune, etc.