Natural Capital and Biodiversity

Natural Capital and Biodiversity

Natural Capital Overview

  • Natural Capital (CI): Encompasses natural resources and ecosystem services.

Natural Resources

  • Definition: Materials derived from Earth that can be utilized for economic gain.
  • Examples: Water, minerals, lumber, fertile soil, coal, oil, natural gas.
  • Classification: Can be categorized as either renewable or non-renewable resources.

Ecosystem Services

  • Definition: The benefits that humans receive from ecosystems. These services are vital for human well-being and survival.
  • Provisioning Services:
    • Provide tangible goods that people can use directly.
    • Examples: Lumber, water (drinking, irrigation), furs/leather, various food crops, medicinal plants, minerals, and fuels (e.g., oil, coal, natural gas).
  • Regulating Services:
    • Involve cycles and systems that regulate environmental conditions, maintaining stability.
    • Examples: Flood control provided by wetlands, various biogeochemical cycles (e.g., carbon, nitrogen, water cycles), and photosynthesis (regulating atmospheric composition).
  • Cultural Services:
    • Provide recreational and aesthetic value, enriching human experience.
    • Examples: National parks and city parks for recreation, natural landscapes that inspire art and creativity, and nature's contribution to spiritual enrichment.
  • Supporting Services:
    • Fundamental ecosystem processes that would be exceptionally difficult and costly for humans to replicate or regulate through artificial means.
    • Examples: Pollination (essential for plant reproduction and agriculture), water purification (natural filtration by ecosystems), and decomposition (breaking down organic matter, recycling nutrients).

Biodiversity

  • Definition: The variety of living things within an ecosystem.
  • Types of Diversity: Includes genetic diversity (variation within a species), species diversity (variety of species), and habitat diversity (variety of habitats or ecosystems).
  • Benefits for Humans:
    • Enhanced Ecosystem Stability: Biodiverse ecosystems are more resilient and less prone to catastrophic events such as food web collapses, widespread species extinctions, or other severe ecological disruptions.
    • Potential for Medical Cures: A significant portion of modern medicine originates from natural sources.
      • Statistic: Approximately 70\% of prescription drugs are derived from natural sources.
      • Specific Examples:
        • Taxol: A crucial cancer drug, sourced from the rare Pacific yew tree.
        • Horseshoe Crabs: Produce a coagulant that is vital for pharmaceutical testing and medical applications.
    • Economic Benefits and Stability: High levels of genetic, species, habitat, and ecosystem diversity are economically advantageous and contribute to overall ecological and economic stability.

Measuring Biodiversity

  • Species Diversity:
    • Definition: Encompasses both the number and variety of species present in a particular ecosystem or community.
    • Components:
      • Species Richness: Refers to the total number of different species observed in a given area.
      • Species Evenness: Indicates the comparative number of individuals present for each species, assessing how equally distributed the individuals are among the different species.
  • Example: Species Diversity of Trees in Two Forest Communities
    • Scenario: Two hypothetical forest communities (Community 1 and Community 2) each have a total of 16 trees and 4 different species of trees (Species A, B, C, D).
    • Community 1 Data:
      • Total number of trees: 16
      • Total number of tree species (species richness): 4
      • Species Evenness (distribution of individuals per species):
        • \text{Species A: } \frac{4}{16} = 25\%
        • \text{Species B: } \frac{4}{16} = 25\%
        • \text{Species C: } \frac{4}{16} = 25\%
        • \text{Species D: } \frac{4}{16} = 25\%
      • Observation: Community 1 exhibits high species evenness, as each species is represented by an equal number of individuals.
    • Community 2 Data:
      • Total number of trees: 16
      • Total number of tree species (species richness): 4
      • Species Evenness (distribution of individuals per species):
        • \text{Species A: } \frac{1}{16} = 6.25\%
        • \text{Species B: } \frac{11}{16} = 68.75\%
        • \text{Species C: } \frac{2}{16} = 12.5\%
        • \text{Species D: } \frac{2}{16} = 12.5\%
      • Observation: Community 2 exhibits low species evenness, as Species B heavily dominates, while Species A is minimally represented.
    • Conclusion: Both Community 1 and Community 2 share the same species richness (number of different species). However, Community 1 possesses a greater species evenness compared to Community 2. Consequently, Community 1 is considered to have a greater overall species diversity. This demonstrates that biodiversity is not just about the number of species, but also their relative abundance.