The major factor influencing plant communities that exist in an area is the climate, in association with rock type, landforms, water and soil. Locally climate may be modified.
Succession is the changes that occur over time as a plant community reaches a seral climax. It is influenced by - competition, number of new species and environmental stress, for example, lack or water.
Seres
An ecosystem passes through several stages before it reaches a climatic climax. These are called seres.
Particular species are associated with each sere, with certain species becoming dominant. This progression through seral stages is shown below:
Climax communities
If natural conditions are not interrupted climactic climax is the final stage that seres reach. It is the natural vegetation that should be found in an area. For example, for most of the UK this would be deciduous woodland.
Plagio Climax: This is where the resultant community has been permanently influenced by humans. For example, by burning or grazing.
Sub climax: If vegetation does not reach its climax as a result of interruptions by local factors such as soil changes or differences in parent rock. The interruptions are known as arresting factors.