Secondary succession refers to the sequential changes in vegetation that occur after a disturbance such as wildfires, hurricanes or human alterations. The rate of change in secondary succession is faster than in primary successions. The studies at different scales on the phenomena studied to understand succession has produced contrasting theories on the succession process. Arguments as to whether succession features competition among plants or some sort of positive process where the presence of one species reinforces the subsequent occurrence of another species at the site have produced considerable argument among ecologists. Ecological models that reproduce successional patterns provide insight into this issue as well as in the nature of successional outcomes. Restoration ecology represents a significant application of succession theory.

Key Concepts:

• Secondary successions are the changes in vegetation that occur after agricultural abandonment or the disturbance of an existing ecosystem. They can be contrasted with primary successions that occur on new substrates.
  
• The concept of succession has a long history in ecology and is a central concept in understanding the dynamics of ecosystems.
  
• There have been and continue to be considerable debate about the nature of succession. The time and space scales considered in ecological succession studies have a pronounced effect on the processes and resultant patterns identified in the studies.
  
• The concept of secondary succession and how it functions is essential a systems theory application in ecology.
  
• Models of ecological succession have developed to investigate the roles of individual species and even of individual plants on determining the patterns of successional change.
  
• Complex nonlinear responses in ecosystems components and the environment can produce complex successions with multiple stable states and multiple paths.
  
• Secondary succession has significant application in the restoration of altered ecosystems.