Impact of Natural Disruptions on Ecosystems

Nov 19, 2024

Lecture Notes: Natural Disruptions to Ecosystems

Key Concepts

  • Objective: Explain how natural disruptions impact ecosystems.
  • Skill Practice: Describing trends and data.

Natural Disturbance

  • Definition: Natural events disrupting structure and function of ecosystems.

    • Interrupts energy and matter cycling.
    • Displaces organisms.
    • Can reshape or destroy ecosystems.

  • Examples:

    • Tornadoes
    • Hurricanes
    • Fires
    • Asteroid impacts (e.g., asteroid that killed the dinosaurs)

  • Comparison to Human Disturbance:

    • Natural disturbances can be more impactful.

Time Scales of Natural Disturbances

  1. Periodic Events

    • Occur with regular frequency (predictable)
    • Example: Wet and dry seasons in savannahs.

  2. Episodic Events

    • Occur frequently but irregular intervals
    • Examples: Hurricanes, droughts, fires.

  3. Random Events

    • Unpredictable timing
    • Examples: Earthquakes, asteroid strikes.

Natural Climate Change

  • Causes:

    • Changes in Earth's orbit and tilt.
    • Result in ice ages and warmer periods.

  • Observations:

    • Temperature varies over centuries (cool and warm periods).
    • Natural CO2 level variations.

  • Human vs. Natural Climate Change:

    • Current CO2 levels exceed natural historical variations.

Sea Level Rise

  • Causes:

    • Increased CO2 leads to warmer temperatures.
    • Melting polar ice caps.
    • Thermal expansion.

  • Habitat Implications:

    • Loss of coastal estuaries.
    • Changes in aquatic plant exposure to sunlight.
    • Flooding of terrestrial coastal ecosystems.

Migration Due to Environmental Change

  • Examples of Migration:
    • Wildebeest following rain patterns.
    • Marine species relocating due to temperature shifts.
    • Birds adjusting migration timing due to climate change impacts on food availability.

Practice FRQ: Analyzing Data Trends

  • Task: Describe relationship between latitude and leaf date changes on a U.S. map.
  • Considerations: Impact of climate change on plant phenology.

Conclusion

  • Importance of Understanding: Natural disruptions and climate change significantly influence ecosystems.
  • Next Steps: Focus on human-driven climate change in future units.

Remember to review the concepts of natural disruptions and practice analyzing data trends as part of your study routine.

Full transcript