What characterizes the process of succession in ecosystems?

Succession in ecosystems is characterized by a gradual change over time following a disturbance. This process involves a series of stages where different species of plants and animals colonize an area, gradually altering the environment, which creates new opportunities for other species to thrive.

After a disturbance—such as a fire, flood, or human activity—initially, the landscape may appear barren, but over time, pioneer species, which are typically hardy and resilient, begin to establish themselves. As they grow, die, and decompose, they contribute organic matter to the soil, improving its quality and allowing more complex plants to take root. This process can lead to a climax community, where the ecosystem becomes stable and is dominated by a diverse range of species.

The other options describe processes or events that do not align with the fundamental concept of succession. Sudden changes do not characterize succession, which is inherently gradual. Immediate recovery suggests a quick return to a previous state, which does not account for the complex sequence of changes inherent in succession. Lastly, while succession can indeed lead to increases in species diversity, this process is typically driven by disturbances rather than occurring without them. Thus, the gradual nature of the change following a disturbance is what defines succession in ecosystems.