SuccessionArticle
Ecological succession is defined as a series of transitions in species composition over ecological time. The process of succession is termed primary succession when it involves establishment of a community in a newly-formed habitat where even soil does not exist, such as on a volcanic island or on the rubble left behind by a retreating glacier - imagine Long Island just after the last glaciers receded - the process of a community of organisms becoming established on the pile of bare rock that formed the island would be an example of primary succession.
Secondary succession occurs when an existing community has been cleared by some disturbance that leaves the soil intact and a new community gradually develops in the area opened by the disturbance. The re-growth of plant communities following forest fires is one example of secondary succession. The development of a community of species following human disturbances like construction or logging would be another good example.
Some common trends in succession:
1. The species composition changes continuously during the succession, but change is usually more rapid in the earlier stages than in the later ones.
2. The total number of species represented increases initially, then sometimes declines slightly, and finally becomes more or less stabilized in the older stages. This trend applies particularly to the heterotrophs, whose variety is usually much greater in the later stages of the succession.
3. Net primary productivity (the amount of energy converted into products of photosynthesis by autotrophs, and available to heteroptrophs) increases until it reaches a stable high level.
Change in net primary productivity during plant succession on an area cleared of an oak-pine forest in Brookhaven, New York. The first rise represents the invasion of the area by herbs. The later rise (after ~14 years) reflects the entrance of larger woody plants into the community.
4. The store of inorganic nutrients held in the organisms and
Secondary succession occurs when an existing community has been cleared by some disturbance that leaves the soil intact and a new community gradually develops in the area opened by the disturbance. The re-growth of plant communities following forest fires is one example of secondary succession. The development of a community of species following human disturbances like construction or logging would be another good example.
Some common trends in succession:
1. The species composition changes continuously during the succession, but change is usually more rapid in the earlier stages than in the later ones.
2. The total number of species represented increases initially, then sometimes declines slightly, and finally becomes more or less stabilized in the older stages. This trend applies particularly to the heterotrophs, whose variety is usually much greater in the later stages of the succession.
3. Net primary productivity (the amount of energy converted into products of photosynthesis by autotrophs, and available to heteroptrophs) increases until it reaches a stable high level.
Change in net primary productivity during plant succession on an area cleared of an oak-pine forest in Brookhaven, New York. The first rise represents the invasion of the area by herbs. The later rise (after ~14 years) reflects the entrance of larger woody plants into the community.
4. The store of inorganic nutrients held in the organisms and