Communities gradually change from one type to another. The sequence of change, from the inital colonisation of a new area to
establishing a relatively stable community, is called ecological succession. There are two main types; primary and secondary. Ecological
succession happens in stages called seres or seral stages; each stage has its own community of organisims, and can usually be
identified by the plants it contains.
Primary succession; colonizing a new area. Primary
succession take splaces in newly formed areas
where no life has previously existed
The process of succession. Succession is a complex process driven by many
factors acting simultaneously. In the early stages, abiotic factors are the most
impotant in determining whcih organisms colonize a habitat. Only those
organisms that can tolerate the hostile enviroment can establish themselves.
These are called pioneer species. Pioneer species arrive haphazardly and those
tolerant of hostile survive. They may change the habitat in ways that favour other
species more. After the pioneer species have become established, biotic factors
become increasingly important in the habitat. When the colonizers die, they enrich
the soil, making the habitat less hostile and allowing other species to become
established. As succession continues, the species diverisity of the community
increases, and the food web of the ecosystem becomes more complex
According to the climax theory, ecological succession leads to a more complex
community with a high species diversity that is in equlibrium with its enviroment.
This has been called the climax community. It is generally assumed that an
increase in species diveristy makes an ecosystem more stable because of the
large number of alternative links between members of the community.
Secondary succession; takes place in the areas
where life is already present but has been altered
in some way. this process is faster than promary
succession because the soil often contains seeds.
There are three main causes of primary succession; 1.Natural catastrophes that
remove existing vegetation 2. Human destruction of climax communities 3. Human
management of habitats to maintain communities at an early succession stage.
In order to prevent secondary succession occuring on and
aerable land, the field would have to be ploughed regularly
Conservation biology and habitat management. Plagioclimaxes; a
relatively stable climax community resulting from ecological succession
that has been arrested, deflected, either directly or indirectly, as a result of
human activity