2: Ecological Succession

Ecological Succession

Natural, gradual changes in the types of species that live in an area

Primary Succession

• Begins in a place without any soil

• Caused by volcanos, landslides, flooding

• Pioneer species

Primary Succession: Step 1

Soil forms as lichens and weather/erosions break down rocks into smaller pieces.

Primary Succession: Step 2

Lichens die and decompose, adding small amount fo organic matter to the rock to make soil.

Primary Succession: Step 3

Simple plants like mosses and ferns can grow int eh new soil.

Primary Succession: Step 4

The simple plants die, adding more organic matter to the soil.

Primary Succession: Step 5

Soil layer thickens, and grasses, then trees, then insects, then small mammals begin to take over.

Secondary Succession

• begins in a place that already has soil (and living organisms)

• Occurs faster and has different pioneer species than primary

• Ex: after forest fires.

Climax Community

A stable group of plants and animals that is the end result of the succession process

• Ex. Grasses in prairies, cacti in deserts

Fire Climax Community

Unstable and periodically burns and regrows (coastal chapparal)