Science.....?

Question

Please Help......Describe how secondary successsion in a forest differs from primary succession after a volcano eruption.

Answer 1

Secondary succession cheats.

Let's put it this way: Primary succession is the regular succession process starting from absolutely nothing. There is probably no soil (a lava flow would leave just hard rock) and probably no indigenous plant life. So you have to start from the very, very bottom - things that can be carried by the wind, burrow into hard rock, and produce most of what they need on their own.

In secondary succession, it's assumed there's a disturbance but it's not a completely catastrophic one (like, for example, the blast from a volcano knocks over all the trees and sets fire to things but there is no lava flow). So there is probably mostly usable soil left, seeds and roots from former plants, and so on. The habitat can't exactly pick up just where it left off, but it hardly needs all the rock-breakers either. Secondary succession, therefore, usually involves far fewer stages which proceed far more rapidly.

Of course, even secondary succession won't occur if whatever disturbs the environment lingers to CONTINUE disturbing it. If a volcano continues to blow dark clouds out which block sunlight, you won't have succession at all!

Answer 2

Secondary forests generally have less biodiversity because they are made up of plants that re-entered the area, and not the plants that were originally there (since those were all killed off.) Also, a volcanic eruption may change the composition of the soil and make it more difficult for some plants to grow. There is more information at the source I linked.