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.

Primary Secondary and 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.

Start your Timeline in Your NB What will you draw here to represent the beginning of primary succession? Year Zero

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.

Add to your Timeline in Your NB What type of plants do you think will first reappear? Draw them here. Year Zero Months to years later

Lichens and Mosses on Rocks

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.

Grass

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.

Add to your Timeline in Your NB Think about what you know about succession, then draw what type of plant you now think will grow in this area Year Zero Months to years later Years later

Ferns

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.

Tropical Flowering Plants

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.

Add to your Timeline in Your NB After many years have passed, what type of plants will now be found in this area if no other disturbances occur? Draw these here. Year Zero Months to years later Years later Many Years Later

Monkey Pod Tree

Ecosystem Reaches Equilibrium

The new ecosystem is now full of varied types of life, plants and animals live successfully together.

Disaster Strikes…

The island is burned to the ground 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.

Start your Timeline in Your NB What will you draw here to represent the beginning of secondary succession? Year Zero

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 or small plants will begin to grow on existing soil

Ferns or small shrub-like plants can quickly fill in areas where grasses and smaller plants first grew

Large plants eventually overtake the island. Monkey Pod Tree

The renewed ecosystem is now full of varied types of life, plants and animals live successfully together.

The Ecosystem Once Again Reaches Equilibrium

Complete your Timeline in Your NB What will you draw here to represent the events that happen in secondary succession? Year Zero