Describe the major factors that influence the process of change during primary succession on bare rock exposed by a retreating glacier

Question

What will be an ideal response?

Answer 1

Primary succession will result where a major disturbance has removed virtually all life, such as occurs with a retreating glacier from bare rock. Within several years, pioneer species such as lichens and mosses are able to colonize the rock surface, since these species are easily dispersed and able to tolerate the harsh conditions of this initial environment. These pioneer species will release small amounts of organic matter as they grow and die, modifying the rock surface, making it more favorable for other more complex species. Herbaceous plants and small shrubs begin to replace the original lichens and mosses, out-competing them. These new species, too, modify the environment, and are likewise replaced by other species such as woody plants and trees. Eventually, species become established which create environments that favor their own survival, and are adapted to the specific temperature and rainfall in their region. These species are known as the climax community and will likely be maintained until a major disturbance (i.e. fire or flood) alters the community, possibly to an earlier stage of succession.