APES 9.9 Endangered Species

How Species Become Endangered

  • Poaching:

    • Illegal hunting and trade of animals or their parts.

    • Exotic species are particularly vulnerable (e.g., elephant tusks, rhino horns).

    • Countermeasure: Removing valuable parts (e.g., tusks) to deter poaching.

    • Example: American bison hunted nearly to extinction due to overharvesting.

  • Overharvesting:

    • Species can be hunted or harvested excessively for food or trade.

    • Example: Tigers taken from the wild for the exotic pet trade.

  • Specialized Habitat Requirements:

    • Some species have narrow food and habitat needs (e.g., koalas require eucalyptus trees).

    • Environmental changes (e.g., wildfires) can drastically affect survival.

  • Invasive Species:

    • Invasive species compete aggressively with native species.

    • Example: Zebra mussels outcompete native mussels, leading to endangerment.

  • Climate Change:

    • Alters habitats and ecosystem dynamics, making it hard for species to adapt.

    • Example: Boreal forests may become too warm for cold-adapted species.

Strategies for Protecting Endangered Species

  • Preventing Poaching:

    • Hire armed guards to protect vulnerable populations.

    • Implement strict penalties for poaching offenses.

  • Habitat Protection:

    • Protect natural habitats to allow species to survive and reproduce.

    • Government purchases or designations (e.g., national parks, wildlife preserves).

  • Legislation:

    • CITES: International treaty regulating trade of exotic species.

      • Member countries must establish agencies to monitor species trade.

    • Endangered Species Act: U.S. law empowering Fish and Wildlife Service to protect endangered species.

      • Allows habitat acquisition to aid in species recovery.

  • IUCN Red List:

    • Classification of species based on conservation status.

    • Categories include:

      • Least Concern: Abundant species

      • Near Threatened: Likely to become endangered

      • Endangered: High risk of extinction

      • Extinct in the Wild: No natural populations left

      • Extinct: No individuals remaining on Earth.

Endangerment by Taxon

  • Amphibians: 41% threatened due to climate change and habitat reliance.

  • Mammals: 25% evaluated as endangered.

  • Birds: 13% endangered.

  • Warm Water Coral: 1/3 evaluated as endangered due to ocean acidification.

  • Conifers: 34% endangered due to disease and pest expansion from climate impacts.

Specialists vs. Generalists

  • Specialists: More vulnerable to endangerment due to narrow ecological niches.

  • Generalists: Better adapted to survive changing conditions due to diverse diet and habitat use.

Competition as a Factor in Endangerment

  • Interspecific Competition:

    • Competition between different species can limit resources.

    • Example: Shenandoah salamander endangered due to competition with red-backed salamander.