APES Unit 0: Ecosystem Services, The Tragedy of the Commons, Deforestation, and Ecological Footprints

Ecosystem Services

  • Humans benefit from ecosystems in a multitude of ways; collectively, these benefits are known as ecosystem services.
  • Ecosystem services can be grouped into four broad categories:
    • Cultural: spiritual and recreational benefits; use of nature for science and education; therapeutic and recreational uses.
    • Provisioning: production of food and water; provides humans with water, food, medicinal resources, raw materials, energy, and ornaments.
    • Regulating: control of climate and disease; waste decomposition and detoxification; purification of water and air; pest and disease control and regulation of prey populations through predation; and carbon sequestration.
    • Supporting: nutrient cycles and crop pollination; primary production, nutrient recycling, soil formation, and pollination.

Categories and Examples of Ecosystem Services

  • Cultural

    • Examples: Sustainable fisheries and aquaculture can directly support recreational services.
    • Note: Recreational fishing is linked to healthy aquatic ecosystems.

  • Provisioning

    • Examples: Ecosystems provide a diversity of materials and products (e.g., livestock produce various raw materials such as fiber (wool), meat, milk).
    • Additional points: Provides food and water; supplies medicinal resources, raw materials, energy, and ornaments.

  • Regulating

    • Examples: Keeps pest populations in balance through natural predators and parasites; disease regulation; climate regulation; waste decomposition; water/air purification; carbon sequestration.
    • Significance: Helps maintain ecosystem health and resilience, reducing the need for human-made inputs.

  • Supporting

    • Examples: Supports nutrient cycles and crop pollination; primary production; nutrient recycling; soil formation; pollination.

Ecosystem Services: Benefits and Connections

  • Cultural: Recreational and aesthetic benefits can motivate conservation and sustainable use.
  • Provisioning: Reliable access to food, water, fibers, and materials supports human livelihoods.
  • Regulating: Ecosystem processes that stabilize climate, purify water/air, control pests, and sequester carbon reduce risk and costs to society.
  • Supporting: Underpins all other services by maintaining fundamental ecological processes like soil formation and nutrient cycling.

5.1 – The Tragedy of the Commons

  • Garrett Hardin wrote “The Tragedy of the Commons” in 1968.
  • Core idea: The essay parallels global resource depletion and pollution; seas, air, water, animals, and minerals are “the commons.” Those who exploit commons become rich, but the price is paid as external costs by people on Earth.
  • The tragedy arises when individuals act in self-interest regarding shared resources, leading to resource depletion and degradation for the whole community.

Examples of Environmental Problems Echoing the Tragedy

  • Air pollution.
  • Burning of fossil fuels and consequent global warming.
  • Frontier logging of old-growth forests and slash-and-burn practices.
  • Habitat destruction and poaching.
  • Over-extraction of groundwater and wastewater from excessive irrigation.
  • Overfishing.
  • Uncontrolled human population growth leading to overpopulation.

Limits to the Tragedy of the Commons

  • Breaking a commons into smaller, privately owned parcels fragments the policies governing the entire commons; different standards and practices on one parcel may affect others.
  • Economic decisions are generally short-term, based on world market reactions, while environmental decisions are long-term.
  • Incorporating discount rates into the valuation of resources would incentivize investors to bear short-term costs for long-term gains. ext{discount rate} effects can alter decisions.
  • Privately owned land is subject to market pressure. Example: if privately owned timberland has an annual value increase of 3 ext{ ext{%}} but loan interest rates to purchase the land are 7 ext{ ext{%}}, this may prompt selling or harvesting for short-term profits.
  • Some commons are easier to control than others. Land, lakes, rangelands, deserts, and forests are geographically defined and easier to control than air or open oceans, which do not belong to any one group.

5.2 – Clear-Cutting

  • Clear-cutting: when all trees in an area are cut at the same time.
  • Environmental impacts include:
    • Decrease in biodiversity due to habitat loss.
    • Increased sunlight reaching the ground, warming and drying the environment; not suitable for many forest plants.
    • Temporary increase in available wood, followed by long periods with little to no wood available.
    • Microclimates within the forest change, affecting associated food webs.
    • Reduction in both long-term (old-growth forests) and short-term carbon sinks, leading to more CO_2 entering the atmosphere.
    • Increased water runoff and soil erosion.

Edge Effects

  • Edge effects describe how local environments change along boundaries or edges.
  • Forest edges created during harvesting, especially clear-cutting, alter shade, moisture, and microclimates.
  • As a stand of young trees regrows, the environment changes and can diverge from the original conditions.

Deforestation – Tree Harvesting

  • Deforestation: the conversion of forested areas to non-forested areas used as grasslands for livestock, grain fields, mining, petroleum extraction, fuelwood cutting, commercial logging, tree plantations, or urban development.
  • Natural deforestation can be caused by desertification, forest fires, glaciation, tsunamis, and volcanic eruptions.

Impacts of Deforestation

  • Allows runoff into aquatic ecosystems.
  • Changes local climate patterns.
  • Decreases soil fertility due to erosion; forest soils are moist but quickly dry out without tree cover.
  • Degrades environment with reduced biodiversity and reduced ecological services.
  • 80 h of Earth’s land animals and plants live in forests." (Note: as stated in the source: "Eighty percent of Earth’s land anima ts live in forests.")
  • Increases habitat fragmentation.
  • Reduces available habitats for migratory species (birds and butterflies).
  • Threatens extinction of species with specialized niches.

Deforestation Mitigation Steps

  • Adopting uneven-aged forest management practices.
  • Educating farmers about sustainable forest practices and their advantages.
  • Monitoring and enforcing timber-harvesting laws.
  • Growing timber on longer rotations.
  • Reducing fragmentation in remaining large forests.
  • Reducing road building in forests.
  • Reducing or eliminating clear-cutting.
  • Relying on more sustainable tree-cutting methods, including selective and strip cutting.

5.11 – Ecological Footprints

  • An ecological footprint is a measure of human demand on Earth’s ecosystems.
  • It is a standardized measure of demand for natural capital (world’s stocks of natural assets, which include air, geology, soil, water, and all living things).
  • Ecological footprints represent the amount of biologically productive land and sea necessary to supply the resources a human population consumes and to assimilate associated waste.
  • This concept helps compare human demand with the planet’s ecological capacity to regenerate.