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Explore the process of ecological succession in Yellowstone Park after a forest fire in 1988, including primary and secondary succession stages. Learn about assessing forest health, identifying threats, and maintaining a healthy ecosystem.
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Ecological Succession Chapter 2 Section 2
Bell Work • Imagine you have been hired to oversee the maintenance of a forest. • How would you evaluate the health of the forest? • What actions would you take to keep the forest healthy? • What might be a threat to the health of the forest?
Ecological Succession • In 1988 large areas of Yellowstone Park burned to the ground. • How do you think the park looked the following spring?
The “dead” forest began to change New plant growth began Ecological Succession
Succession 1. Gradual development of a community of organisms over time Succession A. Takes place in all communities B. Takes place over time Succession
Primary Succession • Primary Succession • A. Takes place after an ecosystem is completely destroyed, including its soil • B. There is no soil in this area, usually just bare rock • Example: volcanic eruption
Steps in Primary Succession • 1. After an volcanic eruption, lava covers the land and hardens into rock
Primary Succession • 2.Lichens begin to form on rocks • A. Lichens-plant like organism that is a fungusand algae • B. Acids from the lichens begin to break down the rock • C. These pieces of broken rock and the remains of dead lichens start forming soil Pioneer species- first organisms to grow in a succession example-lichens
Primary Succession • 3. After many years • A. The soil is deep enough for mosses to grow • B. Mosses replace lichens • C. Tiny organisms like insects live the in the lichens and mosses • Their remains add to the soil
Primary Succession • 4. Over time • Soil layer thickens • Moss is replaced by ferns • Next • Growth of grasses and wildflowers • Once the soil is deep enough: • Shrubs and small trees come into the area
Primary Succession • 5. After hundreds or even thousand of years • The soil may be deep enough to support a forest • The final stage of succession is the climax community
Secondary Succession • Secondary Succession • Changes that takes place after an environment is disrupted in some way (the soil must remain intact) • Example-forest fire, hurricane, farm land left unused
Secondary Succession • 1. fast growing grasses and non-woody plants appear
Secondary Succession • 2. Larger shrubs move in
Secondary Succession • 3. Fast growing trees (such as pines) move in • 4. These are followed by slower-growing hardwood trees
Secondary Succession • 5. As new plants take root and grow, animals begin moving back in the ecosystem • Succession ends with a climax community (when species have adapted to the average conditions in that area)
