What does the term "ecological succession" refer to?

The term "ecological succession" refers to the gradual process by which ecosystems develop over time. This concept encompasses the progression of species composition and community structure in a particular area following disturbances or the initial establishment of ecosystems. Succession can occur in many forms, including primary succession, which happens in lifeless areas such as a new volcanic island, starting from bare substrate, and secondary succession, which occurs in areas where a disturbance has destroyed a community but left the soil intact, such as after a forest fire. This process is characterized by a series of stages where different types of plants and animals colonize the area, leading to changes in the environment and paving the way for more complex ecosystems.

In contrast, the other options describe different concepts or processes that are not directly related to ecological succession. Random changes in climate pertain to natural variability and do not imply a structured progression of ecosystem development. The creation of new ecosystems without prior disturbance does not accurately represent the nature of succession, as this process often begins in response to disturbances or changes in the environment. Lastly, immediate recovery after a disaster is more akin to resilience rather than succession, as it does not capture the long-term changes and gradual transitions in species composition that characterize ecological succession.