Understanding Biodiversity

Biodiversity

• The variety of life on Earth includes species, ecosystems, and genetic diversity within species.
• Biodiversity is crucial for sustaining ecosystems and supporting human well-being.

Two Components of Biodiversity

• Species Diversity: The variety of species found in a specific habitat or ecosystem, illustrated by thousands of species in a rainforest.
• Genetic Diversity: Variations in genes within a species, evidenced by different breeds of dogs or rice strains.

Reasons for Preserving Biodiversity

• Ecological Stability: Biodiversity supports pollination, water purification, and climate regulation in ecosystems.
  • Pollinators like bees and butterflies help maintain plant populations, which is important for ensuring food security.
• Economic Benefits: Industries such as agriculture, medicine, and tourism rely on biodiversity.
  • The Pacific yew tree produces Taxol, which is a compound used in cancer treatment.
• Cultural and Aesthetic Value: Biodiversity contributes to cultural identity and spiritual practices and provides inspiration.
  • Indigenous Amazon tribes use diverse plants for traditional medicine, and eco-tourism is enabled by national parks.

HIPPO: Major Threats to Biodiversity

• HIPPO is an acronym representing major threats to biodiversity and species extinction.

H – Habitat Destruction

• Habitat destruction involves the loss or degradation of natural environments due to human activities like deforestation, urbanization, and agriculture.
  • Clearing the Amazon rainforest for cattle ranching and soybean farming destroys habitats for species like jaguars and macaws.

I – Invasive Species

• Invasive species are non-native species introduced into an ecosystem that outcompete or prey on native species or bring diseases.
  • Burmese pythons in Florida's Everglades prey on native animals which disrupts the ecosystem.

P – Pollution

• Pollution involves contaminants like plastics, pesticides, oil spills, and industrial waste harming species and ecosystems.
  • Chemical runoff from farms causes algal blooms in water bodies, which creates dead zones.

P – Population Growth (Human)

• Increasing human population puts pressure on natural resources, leading to overconsumption, habitat destruction, and pollution.
  • Expanding cities and farmland in countries like India and China leads to habitat loss for species such as tigers and elephants.

O – Overexploitation

• Overexploitation includes overhunting, overfishing, and excessive resource use depleting populations faster than they can recover.
  • Overfishing of Atlantic cod in the 20th century led to the collapse of the fishery.

Fire Exclusion in U.S. Forests

• 20th-century fire suppression policies led to an accumulation of dry vegetation, creating highly flammable conditions.
• More intense and destructive fires resulted from the fire suppression policies.

Addressing the Problem of Fire Exclusion

• Prescribed Burns: Controlled fires set to reduce fuel buildup and restore natural fire cycles.
• Thinning Forests: Removing excess vegetation and small trees to prevent severe wildfires.
• Public Awareness and Policy Changes: Recognizing the ecological role of fire and promoting responsible fire management.

Ecosystem Management in National Forests

• This holistic approach maintains healthy, sustainable ecosystems while balancing environmental, economic, and social needs.
• The approach considers long-term ecological health.

Ecosystem Management Methods

• Selective Logging: Harvesting only certain trees to maintain forest structure and biodiversity.
  • In the Pacific Northwest, selective logging protects old-growth forests while allowing timber production.
• Habitat Restoration: Restoring ecosystems affected by human activity, such as replanting native vegetation and reintroducing species.
  • Wetland restoration projects improve water filtration and provide habitat for wildlife.
• Adaptive Management: Adjusting policies based on scientific monitoring and changing environmental conditions.
  • If a forest's wildlife population declines, management practices may shift to focus on habitat conservation.

Overgrazing and Desertification

• Overgrazing reduces vegetation and exposes soil to erosion when livestock consume vegetation faster than it regenerates.
• Overgrazing leads to desertification, where fertile land turns into desert.
  • In the Sahel region of Africa, overgrazing combined with drought has contributed to widespread desertification.

Practices to Reduce Overgrazing

• Rotational Grazing: Moving livestock between different grazing areas to allow vegetation time to recover.
  • Farmers in the U.S. Great Plains use rotational grazing to maintain healthy grasslands.
• Stocking Rate Management: Limiting the number of animals per unit of land.
  • Ranchers in Australia monitor forage availability and adjust livestock numbers.

Use of Fire in Rangelands

• Fire is used to manage rangelands.

Why Fire is Used in Rangelands

• Reducing Invasive Species: Eliminating non-native plants that outcompete native grasses.
• Restoring Nutrients: Burning plant material returns essential nutrients to the soil, promoting healthy grass regrowth.
• Preventing Woody Plant Encroachment: Maintaining open grassland ecosystems.

Example of Fire Use in Rangelands

• In the Flint Hills of Kansas, prescribed fires maintain tallgrass prairies by preventing the spread of invasive shrubs and trees.

Ecological Terms

• These are definitions and examples for ecological restoration terms.

Restoration

• Restoration involves returning an ecosystem to its original condition before degradation by reintroducing native species and restoring natural processes.
  • Reforestation of Yellowstone National Park after the 1988 wildfires is an example of restoration.

Rehabilitation

• Rehabilitation involves improving a damaged ecosystem to a functional state, enhancing ecosystem services.
  • Converting abandoned farmland into grasslands to prevent soil erosion in the Midwest U.S. is an example of rehabilitation.

Remediation

• Remediation involves removing pollutants or contaminants from the environment.
  • Cleaning up an oil spill in the Gulf of Mexico using bacteria that break down petroleum is an example of remediation.

Mitigation

• Mitigation includes actions taken to reduce or offset environmental damage.
  • A construction company creating wetlands to compensate for the destruction of natural wetlands during highway development is an example of mitigation.

Environmental Problems with Mining

• Mining operations clear large areas of land, leading to deforestation and loss of biodiversity.
  • Mountaintop removal mining in Appalachia has destroyed forests and altered river ecosystems.

Environmental Effects of Water Pollution due to Mining

• Mining can release toxic chemicals into water sources, contaminating drinking water and harming aquatic life.
  • Acid mine drainage from coal mines in West Virginia has polluted rivers, making them unsafe.

Environmental Effects of Air Pollution due to Mining

• Mining activities produce dust and emissions that contribute to respiratory diseases and climate change.
  • The release of sulfur dioxide from mining operations has contributed to acid rain.

Criticisms of the 1872 General Mining Law

• No Environmental Protections: It does not require mining companies to restore land or clean up pollution after operations end.
• Cheap Land Sales: Companies can purchase public land for mining at extremely low prices, leading to resource exploitation.
• Taxpayer Burden: It does not require companies to pay royalties for minerals extracted, meaning taxpayers bear the cost of cleanup and land restoration.
  • Mining companies purchased federal land for a few dollars per acre but extracted billions of dollars' worth of minerals, leaving behind toxic waste.

Ice Cores

• Ice cores are cylindrical samples drilled from ice sheets and glaciers that preserve atmospheric and environmental data.

How Ice Cores Determine Past Climate History

• Scientists analyze ice cores.
  • Gas Bubbles: By analyzing air bubbles trapped in the ice, scientists can measure historical greenhouse gas levels.
    • Ice cores from Antarctica show that CO₂ levels have fluctuated over glacial and interglacial periods.
  • Isotopic Composition: Analyzing the ratio of oxygen isotopes reveals past temperatures.
    • Ice core data from Greenland confirm the occurrence of past ice ages and warming periods.
  • Dust and Particles: Layers of volcanic ash, dust, and pollen evidence of ancient volcanic eruptions.
    • Ice cores from the Arctic contain evidence of ancient volcanic eruptions, such as Mount Tambora’s eruption in 1815, which led to the "Year Without a Summer."
• These ice core records help scientists understand long-term climate trends and predict future climate changes.

Greenhouse Effect

• Gases in Earth's atmosphere trap heat from the Sun, preventing it from escaping back into space.
• Greenhouse gases absorb some of this heat and re-radiate it in all directions, including back to Earth's surface.
• This trapped heat increases global temperatures.

Consequences of Global Warming

• Rising Sea Levels: Melting glaciers and ice sheets, along with thermal expansion of seawater, lead to coastal flooding.
  • Cities like Miami and Jakarta are experiencing more frequent flooding.
• More Extreme Weather: Increased temperatures lead to stronger storms, heatwaves, droughts, and wildfires.
  • The intensity of hurricanes is linked to warmer ocean temperatures.
• Ecosystem Disruptions: Many species struggle to adapt to changing temperatures, leading to habitat loss and biodiversity decline.
  • Coral reefs are dying due to ocean warming and acidification, causing widespread coral bleaching.
• Threats to Agriculture and Food Supply: Changes in temperature and precipitation patterns reduce crop yields and increase food insecurity.
  • Prolonged droughts in California have decreased water availability for farming, impacting food production.

Anthropogenic Air Pollutants

• Carbon Monoxide (CO): Reduces oxygen delivery in the bloodstream.
• Sulfur Dioxide (SO₂): Contributes to acid rain.
• Nitrogen Oxides (NOₓ): Leads to the formation of ground-level ozone (smog).

Legislation Regulating Air Pollution in the U.S.

• The Clean Air Act (CAA) of 1970 (amended in 1977, 1990).
• It sets limits on emissions from industries, vehicles, and power plants.
• It authorizes the Environmental Protection Agency (EPA) to enforce air quality standards.

Controversy Surrounding the Clean Air Act

• Regulation of greenhouse gas emissions is controversial, with debates over economic impacts.
• Stricter emissions limits are viewed as harmful to economic growth and job creation.
  • The debate over the Clean Power Plan (2015).

Carbon Cycle

• Describes how carbon moves through Earth's atmosphere, biosphere, hydrosphere, and geosphere.

Biological Sources and Sinks of Carbon

• Sources: Respiration by plants, animals, and decomposers releases carbon dioxide (CO₂) into the atmosphere.
• Sinks: Photosynthesis by plants and algae absorbs CO₂ from the atmosphere, storing carbon in biomass.

Geologic Sources and Sinks of Carbon

• Sources: Volcanic eruptions and weathering of carbonate rocks release carbon into the atmosphere.
• Sinks: Carbon is stored in fossil fuels (coal, oil, natural gas) and sedimentary rocks like limestone.

Anthropogenic (Human) Sources and Sinks of Carbon

• Sources: Burning fossil fuels, deforestation, and industrial activities release large amounts of CO₂ and methane (CH₄).
• Sinks: Oceans absorb CO₂, but excessive absorption leads to ocean acidification.
• Some carbon capture and storage (CCS) technologies are being developed to artificially sequester carbon.

Environmental Legislation

• 1956 - Water Pollution Control Act includes grants for communities willing to act on sewage and industrial water pollution control.
• 1957 - The Price-Anderson Act limited liability of owners of nuclear power plants and government in case of accidents.
• 1964 - Wilderness Act protects wilderness areas.
• 1966 - Freedom of Information Act (FIA) provides that “any person” can make requests for government information without identifying themselves or explaining why they want the information.
• 1966 – National Historic Preservation Act created the National Register of Historic Places, the list of National Historic Landmarks, and the State Historic Preservation Offices to preserve historical and archaeological sites in the United States of America.
• 1968 - National Wild and Scenic Rivers Act identified scenic rivers for preservation.
• 1969 - National Environmental Policy Act (NEPA) requires environmental impact statements (EIS) for all projects involving federal land and established Council on Environmental Quality.
• 1970 - Occupational Safety and Health Act of 1970 promotes safe conditions for workers.
• 1970 - Clean Air Act (revised 1977, 1990) sets health standards for clean air that states and industry must meet, allows industry to trade emissions permits to reduce pollution, and established the Environmental Protection Agency (EPA); states develop implementation plans.
• 1970 - Federal Pollution Control Act or Clean Water Act (revised 1985) established National Pollution Discharge Elimination System (NPDES) that requires permits for discharge of pollutants into surface waters and is regulated by the EPA; requires best practical control technology (BPC) for treatment of pollution and required sewage treatment for all municipalities by 1988; states must develop implementation plans.
• 1972 - Federal Pesticides Control Act required registration of pesticides and was amended in 1996.
• 1972 - Marine Protection Research and Sanctuaries Act (Ocean Dumping Act) expands on 1899 River and Harbors Act to include oceans.
• 1972 - Marine Mammals Protection Act prohibits the taking of marine mammals.
• 1972 - Coastal Zone Management Act provides Federal funds for state management of coastal waters.
• 1972 - Noise Control Act regulates noise pollution from sources like airports and industry.
• 1973 - Endangered Species Act protects species designated as endangered.
• 1974 - Great Lakes Water Quality Agreement (amended 1978) made between the US and Canada to regulate pollution in the Great Lakes.
• 1974 - Safe Drinking Water Act sets standards for drinking water and protects groundwater and was amended in 1986 and 1996.