What typically triggers secondary succession?

Secondary succession is primarily triggered by disturbances that alter an existing ecosystem but do not completely destroy it. The destruction of a community by human activities, such as deforestation, urban development, or pollution, often leaves behind soil and some remnants of the original ecosystem, allowing for the possibility of new growth and species to re-establish themselves.

In contrast, natural disasters like volcanic eruptions can lead to primary succession, as they typically create new land where no soil or ecosystem previously existed. The formation of new land is also associated with primary succession, where life must start from scratch. Migration of various species may contribute to succession processes but is not a direct trigger for secondary succession on its own. Thus, the destruction caused by human activities best characterizes the events that initiate secondary succession.