Conservation Biology Notes

Learning Goals

  • Distinctions Among Concepts:

    • Ecology: Study of relationships among organisms and their environment.
    • Conservation Biology: Applied science aimed at preserving species and ecosystems.
    • Environmentalism: Political viewpoint advocating for ecological protection.

  • Reasons for Conservation: Understand multiple motivations for conservation efforts.

  • Factors Influencing Conservation: Recognize the challenges involving economic trade-offs and human impacts on conservation.

The Biodiversity Crisis

  • Species Diversity:
    • Approx. 2 million species described; estimates suggest 8.7 million may exist.
    • Human activities dramatically altering global ecosystems, leading to a potential sixth mass extinction (Anthropocene).

Conservation Biology

  • Integrated Fields: Combines ecology, physiology, molecular biology, genetics, economics, and evolutionary biology.
  • Distinction: Not a political movement (environmentalism), though it can inform policy.

Four Levels of Biodiversity

  • Genetic Diversity: Variation in genes within and between populations.
    • Threatened by habitat loss and intervention (e.g., zoos).
  • Species Diversity: Variety of species within an ecosystem.
    • % at risk: 12% of birds, 21% of mammals, 32% of amphibians.
  • Ecosystem Diversity: Range of ecosystems in an area; decreased through human action (e.g., wetland destruction).
  • Higher Level Taxonomic Diversity: Loss of species threatens entire families or orders.
    • Example: Tuatara species in New Zealand represent Rhynchocephala class.

Justifications for Conservation

  1. Self Interest:
    • Provides food, recreation, raw materials, water, climate regulation, and ecosystem services.
    • Example: Genetic traits from wild varieties help improve crops.
  2. Theistic/Philosophical/Aesthetic/Ethical:
    • Ethical beliefs underpin many conservation efforts.
    • Historical importance of human connection with nature (John Muir).

Threats to Biodiversity

  1. Habitat Destruction:
    • Significant loss of grasslands and forests, leading to fragmentation.
  2. Fragmentation:
    • Individual habitat patches become biological "islands," risking populations.
  3. Ecosystem Process Disruption:
    • Altered natural processes (e.g., fire regimes, grazing patterns) can endanger species.
  4. Introduced Species:
    • Exotic species disrupting local ecosystems (Example: brown tree snake in Guam).
  5. Overexploitation:
    • Species like Stellar’s sea cow hunted to extinction.

Vulnerability Factors for Species

  • Endemism: Limited geographical range increases extinction risk.
  • Rarity: Naturally rare species face challenges; hard to monitor.
  • Small Population Size: Increased risk of genetic drift and inbreeding.
  • Ecological Specialization: Specialized species face extinction if habitat changes occur.
  • Utility to Humans: Attractive species face hunting pressure or habitat loss.

Economic and Human Factors in Conservation

  • Conflicting Demands: Balancing endangered species' habitat needs against human industry (timber, mining, etc.).
  • Economic Value of Whales: Shift toward whale-watching vs. hunting, demonstrating potential for more sustainable economic models.

Protected Areas and Management

  • Reserve Size Debate: Larger vs. smaller reserves; both have pros/cons for various ecosystems and species.
  • Marine Reserves: Protecting areas can enhance fisheries; land reserves can support pollinators.

Case Studies in Conservation

  • Monarch Butterfly Biosphere Reserve: Importance of preserving monarch habitats while balancing economic pressures of local populations.
  • Indigenous Involvement: Traditional practices contributing to the conservation of endemic species while meeting human needs.