In the context of community dynamics, which of the following is an example of an extreme disturbance to an ecosystem?

• A. A major volcanic eruption that rapidly buries a landscape in ash and lava
• B. A gradual increase in average temperature over many decades
• C. Seasonal leaf fall in a temperate deciduous forest
• D. Daily fluctuations in light intensity due to passing clouds

Answer: (A)

Verified step by step guidance

1. Understand the concept of disturbance in community ecology: a disturbance is any event that disrupts ecosystem, community, or population structure and changes resources, substrate availability, or the physical environment.
2. Identify characteristics of an extreme disturbance: it is typically sudden, severe, and causes significant changes to the ecosystem, often leading to a reset or major alteration of community structure.
3. Evaluate each option based on these criteria: a major volcanic eruption is sudden and severe, rapidly burying the landscape and drastically altering the environment.
4. Compare with other options: gradual temperature increase is slow and less immediately disruptive; seasonal leaf fall is a regular, predictable event; daily light fluctuations are minor and temporary.
5. Conclude that the major volcanic eruption best fits the definition of an extreme disturbance because of its rapid and profound impact on the ecosystem.