Practice question

Nudation first creates a bare or newly available site, migration then brings propagules into that site, and ecesis follows when those immigrants establish and grow. Later processes include aggregation, competition, reaction, and stabilization, so the stated sequence correctly captures the opening phases. Organisms can drive succession autogenically by changing their own habitat, while floods, erosion, sedimentation, or climate can drive allogenic change. Biological agents such as grazers and pathogens may also redirect succession by altering competitive relationships. Distinguishing the driver from the observed sequence clarifies mechanism: community turnover is the response, whereas substrate development, resource preemption, facilitation, or external forcing explains why replacement occurs. This distinction prevents every temporal fluctuation from being mislabeled as ecological succession. In this context, the keyed term, Nudation → Migration → Ecesis, identifies the relevant mechanism or quantitative relationship and links the observed pattern to its underlying ecological cause. The distinction is testable by measuring changes in organisms, resources, or process rates through time rather than relying on the label alone.