Invasive, Endangered, Keystone Species

Invasive, Endangered, Keystone, and Indicator Species APES

Learning Objectives

  • Endangered Species (TOPIC 9.9)

  • Invasive Species (TOPIC 9.8)

  • Ecological Succession (TOPIC 2.7)

Enduring Understanding

  • EIN-4: The health of a species is closely tied to its ecosystem; minor environmental changes can have significant impacts.

Learning Objectives and Essential Knowledge

  • ERT-2.1.2:

    • EIN-4.B: A keystone species is vital in shaping community structure.

    • EIN-4.B.1: Factors leading to species endangerment include hunting, dietary limitations, invasive species competition, and specific habitat needs.

  • ERT-2.1.3:

    • EIN-4.B.2: Indicator species reflect the ecosystem's quality through presence and abundance indicative of environmental changes.

    • Some species successfully adapt to changes, decreasing extinction risk.

Invasive Species

  • EIN-4.A:

    • EIN-4.A.1: Invasive species can thrive beyond their native habitats.

    • They are harmful when they threaten native species.

  • EIN-4.B.3: Common issues with invasive species include competition for resources.

  • EIN-4.A.2: Many invasive species are r-selected generalists that outcompete native species.

  • EIN-4.B.4: Strategies against invasives include legislation and habitat protection.

Vocabulary

  • Invasive Species

  • Endangered Species

  • HIPPCO

  • Conservation Easement

  • Keystone Species

  • Trophic Cascade

  • Foundation Species

  • Indicator Species (Bioindicator)

Keystone Species

  • Critical to maintaining ecosystem balance; the removal leads to significant ecosystem changes.

  • Can be any trophic level: top predators, primary consumers, or producers.

Example: Kelp Forests

  • Charles Darwin's observation on the biodiversity dependent on kelp highlights its keystone role in ocean ecosystems.

Case Study: Wolves in Yellowstone

  • Historical Context: Gray wolves were exterminated in the 1920s leading to trophic cascades and ecological imbalance.

  • Reintroduction: In 1995, wolves were reintroduced, stabilizing elk populations and restoring ecological balance.

  • Impacts: Restored willows and aspens supported diverse wildlife, enriching the ecosystem.

Foundation Species

  • Similar to keystone species but create and maintain habitat structure.

  • Example species include:

    • Kelp in kelp forests

    • Willows along stream banks

    • Mangroves in coastal regions

Keystone vs. Foundation Species

  • Keystone Species: Impact ecosystem dynamics significantly; removal causes collapse.

  • Foundation Species: Establish and sustain habitat structure; contribute to ecosystem maintenance.

Indicator Species (Bioindicators)

  • Reflect environmental quality; reveal status based on pollutants and ecosystem health.

  • Examples:

    • Lichens: sensitive to sulfur dioxide, indicating pollution levels.

    • Animals like amphibians show environmental health through presence or deformities.

Invasive Species Dynamics

  • Defined as established organisms that negatively affect ecology, economy, and human health.

  • Characteristics: Dominance in new ecosystems due to absence of predators and ecological checks.

  • Examples include:

    • Cane toads, Burmese pythons, zebra mussels, feral cats.

Notable Invasive Examples

  • Cane Toad: Native to South America; problematic in Australia.

  • Zebra Mussels: Disrupt North American waterways.

  • Chytrid Fungus: Affects amphibian populations worldwide.

Control Measures for Invasive Species

  • Strategies include:

    • Prevention: Monitoring materials and awareness.

    • Physical Removal: Trapping and manual removal efforts.

    • Biological Control: Introducing natural predators; mixed results.

    • Chemical Control: Use of pesticides and herbicides.

Endangered Species

  • High risk of extinction; often specialists and K-selected species vulnerable to:

    • Habitat loss and fragmentation

    • Invasive species

    • Pollution

    • Climate change

    • Overexploitation

Protection Strategies for Endangered Species

  • Legislation (CITES, ESA).

  • Habitat protection initiatives.

  • Creation of environmental preserves and conservation easements.

  • Activism and awareness-raising measures.