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Ecological Succession. Equilibrium in Ecosystems. What is Succession? . Succession is the series of predictable changes that occur in a community over time. Succession helps an ecosystem to recover and return to a state of equilibrium after a fire, volcano or other disaster.
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Ecological Succession Equilibrium in Ecosystems
What is Succession? • Succession is the series of predictable changes that occur in a community over time. • Succession helps an ecosystem to recover and return to a state of equilibrium after a fire, volcano or other disaster.
Types of Succession • There are two types of succession: Primary and Secondary
Primary Succsession • Primary Succession occurs where no ecosystem previously existed.
How Can There Be an Area Where No Ecosystem Previously Existed? • New Volcanic Island • Area of Rock Uncovered by retreating Glaciers
Steps in Primary Succession • A new island is formed through long series of volcanic eruptions. No life exists on this new rocky material at first.
How do Living Organisms Get to the New Island? Ocean waves carry spores, seeds, small plants and animals to the new island Birds flying over the island do the same
What Can Live on the New Island? • The newly created island is made of volcanic rock, but no soil. Most large plants with roots can’t grow without soil. • Most animals can’t survive without plants, so how can life exist on this new island?
The First Plants • Small plants like lichens and mosses do not have roots. These small plants have the ability to grow on rocks and slowly break-down the rocks to produce soil.
Succession continues… • The newly produced soil can now start to support small plants with some degree of roots systems. Grasses with small root systems will typically start to grow next.
Weathering of Rock Continues • As more plants grow, the roots of the plants break down the rock further to produce richer and more abundant soil. • Succession continues with larger plants now having the ability to grow. • On many islands, ferns will now begin to grow.
More Weathering… • Over time, larger and more complex plants will begin to grow. Flowering plants will now be seen. • The types of producers become more varied and this sets the stage for animals to be able to survive.
Succession continues… Larger and larger plants now grow, providing food, shelter and nesting places for a variety of animals. Many different types of trees now begin to grow.
The new ecosystem is now full of varied types of life, plants and animals live successfully together.
The island is burned to the ground. The trees, other plants and animals are destroyed. All that is left is the rock and soil.Equilibrium is destroyed and the process of succession must once again begin.
Secondary Succession Secondary Succession occurs following a disturbance to an ecosystem, such as after a devastating fire. • Secondary succession occurs naturally after hurricanes, floods, and tornadoes. • Secondary succession also occurs after farming, logging and mining have disturbed an ecosystem.
Steps of Secondary Succession • Secondary succession occurs in a place where an ecosystem has previously existed. • Secondary succession can happen faster because soil has already been produced. • If soil was not lost in the disturbance, plants can grow more quickly.
After the disturbance, grasses begin to grow on existing soil .
Complex Plants now enter the scene
Large plants soon overtake the island. Monkey Pod Tree
The renewed ecosystem is now full of varied types of life, plants and animals live successfully together.
