Ecological Succession The natural process by which one community of organisms slowly replaces another in an area.

Ecological SuccessionThe natural process by which one

community of organisms slowly replaces another in an area

Two Types of Succession

Facts:Process that occurs where no ecosystem existedStarts after a disturbance where no soil exists begins on bare rock with Pioneer Species :

EX: Mosses and Lichens

Pioneer speciesthe first species to populate an area where Primary succession is taking place – ex: lichen and mosses

1.Primary Succession

Two Types of Succession

2. Secondary Succession: series of changes that occur after a disturbance in an existing ecosystem

– starts after a disturbance where soil exists– Ex: Fire devastates a forest – Area of Rainforest cut down by loggers

Primary Succession; Begins as bare rock and pioneer species; moss and lichen. Over time soil is produced allowing for the growth of grasses…making the soil richer which allows for the growth of shrubs. When the grasses die and shrubs loose their leaves this produces waste which creates an even richer amount of soil allowing for the growth of maples and oak trees.

Eventually the once bare area become dense with tall trees that it leaves little area for more plants to grow, ecosystem is at equilibrium This is called a Climax Community

CLIMAX COMMUNITY• Final Stage of succession

• Usually 1 dominant species

• Community is at equilibrium– Enough producers and consumers to maintain a

healthy ecosystem

• Remains stable unless a natural disaster or major human impact event occurs

Mt. St. Helen

Before Eruption

What stage of succession do you think will now occur, if any?

What appears to be growing on the bare rock?

Describe what has happened.

Secondary Succession