Succession Ecosystems Unit, May 18, 2007

Do ecosystems stay the same forever, or do they change

Ecosystems are always changing! Sometimes the changes are fast (fires, earthquakes) and sometimes they are slow (a new tree growing).

*Succession is the gradual process by which certain species replace other species in an ecosystem. The organisms that are present at one stage change the ecosystem in some way that makes it possible for other species to live. Succession

A.Bare Rock and Lichens: Lichen (algae + fungus) grow on rocks and produce acids that help to break down the rock. Dead lichen and small rock pieces form soil. B.Mosses and Ferns: Mosses and ferns are able to grow on the thin, nutrient poor soil. As they die and decompose the soil layer gets thicker and more nutrient rich. C.Grasses, Flowers and Shrubs: More plants can now grow in the fertile soil. They attract insects, birds and small mammals. The soil layer gets even richer. D.Trees: Trees can now grow in this ecosystem. They provide shelter and habitat for other animals and plants. Forest Succession:

Succession is a slow process! It can take hundreds or even thousands of years. ANIMATION

Succession of a Wetland. A. Wetland in a forest

Succession of a Wetland. A. Wetland in a forest B. Erosion starts to fill in the wetland with soil. The wetland gets smaller.

Succession of a Wetland. A. Wetland in a forest B. Erosion starts to fill in the wetland with soil. The wetland gets much smaller. C. The wetland has completely filled in with soil and mosses and is now a bog with young trees growing on it.

A farmer has cut down a forest to have a field to grow his crops. Predict what will happen to the field if the farmer decides to move and leave the farm abandoned! How long will it take for the land to be a mature forest again? Mature Beech and Maple Forest 0-5 yrs 5-10 yrs yrs yrs