Biodiversity and Conservation Study Notes

Wildlife Conservation in Namibia

  • Namibia addresses conservation of biological resources in its constitution (1996).
  • 20% of land is managed by 79 conservancies.
  • Home to largest populations of black rhinos, cheetahs, and growing lion and elephant populations.
  • Ecotourism contributes to sustainable income and serves as a model for other nations.

Species Richness and Biological Diversity

  • Species: Organisms capable of interbreeding but not with others outside their group.
  • Total species on Earth estimated at 2-100 million; 10,000 identified yearly.
    • As of late 2015: 1.6 million named species, including 350,000 plants, 64,000 vertebrates, 800,000 insects.
  • Species richness refers to the variety of species in a community, affected by environmental stress and community isolation.

Importance of Biodiversity

  • Biodiversity supports ecosystem health, and includes:
    • Genetic diversity: variations within species.
    • Species richness: number of species.
    • Ecosystem diversity: variance of ecosystems.
  • Ecosystem services: clean air, water, and soil; biodiversity enhances resilience to disturbances.

Endangered and Extinct Species

  • Extinction: natural process; accelerated by human activities.
  • Approximately 23,000 species endangered as of 2015; includes 26% of mammals, 41% amphibians.
  • Endangered Species Act defines and protects endangered and threatened species.

Human Causes of Species Endangerment

  • Greatest threats: habitat loss, pollution, invasive species, and overexploitation.
  • Habitat fragmentation and degradation mainly due to human activities are significant issues.

Conservation Biology

  • In situ conservation: preserves biodiversity in nature (parks/reserves).
  • Ex situ conservation: preserves biodiversity in controlled settings (zoos, seed banks).
  • Active management and restoring habitats are crucial for effective conservation.

Conservation Policies and Laws

  • Endangered Species Act (1973) protects U.S. endangered/threatened species.
  • International agreements like CITES regulate trade in endangered species.
  • Undertakings such as the Earth Summit aim to decrease extinction rates.