Which of the following is an example of a long-term change to ecosystems?

• A. Seasonal migration of birds
• B. Daily fluctuations in temperature
• C. Primary succession following a volcanic eruption
• D. Temporary flooding after heavy rainfall

Answer: (C)

Verified step by step guidance

1. Understand the concept of long-term changes in ecosystems: These are changes that occur over extended periods and significantly alter the structure, composition, or function of an ecosystem. Examples include processes like succession, climate change, or permanent habitat alteration.
2. Review the concept of primary succession: Primary succession is the gradual development of an ecosystem in an area where there was previously no soil or life, such as after a volcanic eruption. This process can take hundreds or thousands of years, making it a long-term change.
3. Compare the options provided: Seasonal migration of birds and daily fluctuations in temperature are short-term changes that occur regularly and do not permanently alter the ecosystem. Temporary flooding after heavy rainfall is also a short-term event that does not lead to permanent ecosystem changes.
4. Identify why primary succession following a volcanic eruption is the correct answer: After a volcanic eruption, the area is initially barren with no soil or life. Over time, pioneer species like lichens and mosses colonize the area, leading to soil formation and the gradual establishment of a complex ecosystem. This process represents a long-term change.
5. Conclude that primary succession following a volcanic eruption is an example of a long-term change to ecosystems because it involves the creation and development of an entirely new ecosystem over an extended period.