Ecological Succession Notes

Ecological Succession

Ecosystems are dynamic and undergo constant change due to disturbances such as hurricanes, volcanic eruptions, and forest fires. These events can leave behind barren landscapes, but life gradually returns through a process called ecological succession.

Ecological Succession

Ecological succession is the process by which living things repopulate an area after a disturbance. This repopulation occurs in a series of stages.

Primary Succession

Primary succession occurs when there is no soil or life present in the ecosystem. Examples include:

  • Volcanic eruption where lava hardens into rock.

  • Glaciers receding and leaving behind barren rocks.

Pioneer species, such as lichens and mosses, are the first to return to an area. These species help to break down the rock and create soil. Over time, grasses, herbs, and wildflowers establish themselves. The progression continues with tree seedlings, eventually leading to a climax community.

The stages may include:

  • Lichens and Mosses

  • Grasses, Herbs and Wildflowers

  • Shrubs

  • Tree seedlings (e.g., Aspen, Black Spruce, Jack Pine, White Spruce, Balsam Fir, Paper Birch)

Secondary Succession

Secondary succession occurs when plants and animals have been wiped out, but the soil remains. Examples include:

  • Clear-cutting

  • Forest fires

In secondary succession, pioneer species are not needed. Grasses, shrubs, and wildflowers return relatively quickly, followed by trees.

The process begins with:

  • Fast-growing plants initially dominating the disturbed area.

  • Eventually, a climax community is re-established.

Climax Community

The climax community is the final stage of ecological succession. In this stage, the ecosystem does not change much.

Succession in Coral Reefs

Coral reefs also undergo ecological succession.

  • Primary Succession: An underwater volcano erupts, and lava creates a blank slate. Coral is deposited and begins to grow on the lava flow.

  • Secondary Succession: Through spawning, coral stacks new offspring on top of itself, creating a reef. Boat damage can also lead to secondary succession.

Ecological Succession on a Coral Reef stages:

  • Colonizing Stage: New reef substrate

  • Successionist Stage: Old reef substrate

  • Climax Stage: As of now, there is no recorded observation of the climax stage of reef development.

The video shows the ecological succession on a coral reef over time, with examples of lava flows at different stages of colonization (3 months, 10 years, 15 years, 20 years, 40 years, and 100 years old).