Question

Give an example of a disaster that leads to primary succession and list and explain each of the steps in the succeeding phases of that succession. How does primary succession differ from secondary succession? What type of succession do we see most commonly associated with clear-cutting of forests?

Answer 1

There are many examples available of a disaster that leads to primary succession. For example, Surtsey is a volcanic island off the southern coast of Iceland. It emerged from the Atlantic Ocean in a volcanic eruption in November 1963. After that plants such as sand ryegrass, oysterleaf, and seaside sandplant grown on this island. Here, much of the vegetation is comprised of lichens and mosses. On newly created volcanic islands, these first colonizing plants are weedy species, such as mosses, fast-growing grasses and lichens. They do not grow tall but their reproduction takes place rapidly. These plants die and decompose after germinating and growing. Then their remains create pockets of soil in which other plants, as well as fungi, started growing. New plants grow after that, whose seeds might brought by wind or birds. These new plants and species helps sun-loving grasses, shrubs, and other pioneer species. More plants and animals arrive, and some become colonized on the island. A change occurs in ecosystem with each new arrival. After many years, the biological community transitions from collections of pioneer and intermediate species to a climax community occurred. Therefore, in this way volcanic eruption leads to primary succession.

In primary succession, recently formed rock is colonized by living things for the first time. Secondary succession is the disturbance, in an area that was already occupied by living things and then re-colonized following the disturbance. Secondary succession differs from primary succession in that it starts after a major disturbance such as a drought situation, devastating flood, volcanic eruption, earthquake, etc.

Secondary succession is most likely associated with clear-cutting of forests. Here already living things existed which is being disturbed. Therefore, it is considered under secondary succession.