In this lesson you will learn about the differences between primary and secondary succession. You will also discover how and why each process occurs as well as their importance to the survival of a habitat.
You turn on the television and see that there is breaking news! A wildfire is raging out of control on the west coast of the United States, in California. You call your friends and family who reside there, and are relieved to find that they are safe. However, before you can complete your call, your friend Malcolm asks you to speak to his daughter, who is upset.
Little Kennedy gets on the phone and tells you that she’s worried about the forest and the animals living in the woods near her home. She cries, ”The woods will be gone forever! The bunnies will never be able to live there again.” You tell her that she doesn’t have to worry. She asks,” Why not?” You explain that secondary succession will occur and will help the forest come back. In the end of secondary succession, the animals will be able to return to their homes.
”That’s great,” Kennedy says with excitement. She then asks you, ”But what exactly is secondary succession? Is there a such thing as primary succession?”Believe it or not, new forest communities are being ‘born’ all the time. The earth has been around for millions of years, and since the earth came to be, there have been many natural disasters. Some have been fires, like in the example described above.
Others have been even more devastating, like volcanic eruptions, tornadoes, hurricanes, and many others. Although these events are caused by natural phenomena, they can still wreak havoc on ecological communities. Many of these phenomena offer opportunities for primary and secondary succession to occur.
A Forest is Born – Primary Succession
Hawaii is a place that offers many great examples of primary succession. It has active volcanoes present. As a result, new land is constantly being made.
As the volcanoes erupt and the lava cools, the land near the volcano keeps expanding. The newly formed land has no soil, vegetation, or animals living on it. This is how primary succession begins. In primary succession an ecological forest community is built over a long period of time, starting from the deposit of soil suitable to sustain life and ending with a thriving forest community. Newly formed lava has no soil on top of it. Over time, dust and debris will settle on the newly formed land. Pioneer species, which are the first species to inhabit newly developing ecological communities, will begin to inhabit the land.
Fungi, lichen, and algae are all examples of pioneer species. As the pioneer species complete their life cycles and continue to reproduce and die, their bodies enrich the newly formed soil. As the soil becomes enriched it will be able to support more complex plants. More complex plants will eventually attract insects, birds, snakes, and other animals to the new community. Over time, what was once a barren and lifeless area will become an established and complex forest community.
A Forest is Reborn – Secondary Succession
Earlier we discussed some natural disasters that occur. Most are not as extreme as a volcanic eruption and do not completely disrupt the ecosystem. One type of natural disaster that fits this description is a fire. Most times, the entire community won’t be destroyed by a fire.
Some of the plants and animals will survive, while the ones who die will immediately enrich the soil. What we are describing here is secondary succession. Secondary succession is the process in which a previously established ecological community suffers a relatively minor ecological disturbance (fire, tornado etc), and becomes reestablished. As was described to little Kennedy, the forest will come back after the fire and all the animals that lived in the forest will come back too. The good thing about secondary succession is that, compared to primary succession, it takes a lot less time to occur.
This is because the community still has some of the organisms that were there previously, as well as the soil. It takes less times to rebuild something than to start from scratch.
In primary succession an ecological forest community is built over a long period of time, starting from the deposit of soil suitable to sustain life and ending with a thriving forest community. Pioneer species are the first to inhabit newly developing ecological communities during primary succession.
Fungi, lichen, and algae are all examples of pioneer species. As the pioneer species complete their life cycles, their bodies enrich the newly formed soil. This enriched soil supports more complex plants that attract other organisms to the land. Over time, what was once a barren and lifeless area becomes an established forest community.
Secondary succession is the process in which a previously established ecological community suffers a relatively minor ecological disturbance (fire, tornado etc) and then becomes reestablished. Compared to primary succession, secondary succession takes less time to occur.