What is succession in Ecology?

This lesson is about succession in biology. We'll cover what succession is in general, and we'll learn the difference between primary and secondary succession. We'll also look at some specific examples in different ecosystems.

What Is Succession?

When it comes to inheritance law, a successor is a person who comes after you in a family lineage. Your father was your grandfather's successor, and you are your father's. As your father's successor, you will likely inherit his money when he dies. But you'll change that money a little bit before you eventually pass it on to your own kids. You might invest it, or spend some, or buy property. Those things will be passed onto your children, and in the same way, they will use that inheritance, change it, and pass it on to their children.

Although biology has to do with living species, not money or inheritance, the idea of succession in biology is the same. Succession in biology is the order in which species appear in an ecosystem over time. So, like your father passes his money on to you, the first species in an environment passes on the changes it has made to the second species. The second species changes the environment a little more, maybe creating more ground cover or changing the soil, and then passes that on to the third species to inhabit the area, and so on.

Order of Succession

The species that colonize a new area of land do so in a specific order. Although the species in ecosystems may be different, the general order of succession is the same. Pioneer species are the first species to arrive on the scene. They are usually small plant-like species, like lichen or moss. After the pioneer species are established, larger plants can inhabit the area, like grasses, then shrubs. Finally, trees start to grow and the forest ecosystem reaches a stable place again.

Lichen colonizing a rock.

Succession happens when an environment has been cleared of life, either through a minor disturbance, like a fire, or through something major, like a volcanic eruption. There are two kinds of succession based on the type of disturbance, primary and secondary succession.

Primary Succession

Primary succession occurs when a community, or group of species, evolves from a barren land with no life at all. The soil is completely fresh and devoid of life. An example of primary succession occurs after a volcanic eruption. Hot lava spews from the Earth, coating the land around it. This area near the volcano starts with no life at all. Eventually, seeds will land there and pioneer species will begin to colonize the area. The pioneer species will begin to break down the volcanic rock and establish soil that other plants can grow in.

Stages of primary succession.

Secondary Succession

Secondary succession occurs when there is disturbance that destroys the life in an ecosystem, but the remnants, soil, nutrients, and some seeds may remain. An example is a forest fire. Although the fire burns through the trees and disrupts the animals' habitat, the basic necessities for life still remain. Since there is already nutrient rich soil, the pioneer species do not need to prepare the area for other plants, and succession can occur more quickly. Other incidents that may result in secondary succession include high winds from hurricanes or tornados or excessive flooding.

Ecological succession in a boreal forest immediately after a fire (left) and after colonization (right).

• What is Human Ecology?
• What is ecological succession in Biology?
• Succession in Ecology