Changes in Ecosystems: Ecological Succession

Succession: Gradual rebuilding of an ecosystem that has been drastically changed. 2 types of succession primary or secondary

Primary Succession Begins without soil just rock After lava flow covers an area After glaciers melt

Starts with PIONEER SPECIES such as lichen and moss that do not need soil to survive.

Primary Succession Lichen and moss break down rocks into smaller pieces When lichens die, they decompose, adding nutrients to the rock to make soil

http://www.life.uiuc.edu

Primary Succession Simple plants like weeds and ferns can grow in the new soil http://www.uncw.edu http://uisstc.georgetown.edu

Primary Succession The simple plants die, adding more nutrients to soil The soil layer thickens, and grasses, wildflowers, and other plants begin to take over http://www.cwrl.utexas.edu

Primary Succession These plants die, and they add more nutrients to the soil Shrubs and trees can survive now http://www.rowan.edu

Primary Succession Insects, small birds, and mammals have begun to move in What was once bare rock now supports a variety of life http://p2-raw.greenpeace.org

Climax Community A stable group of plants and animals that is the end result of the succession process Does not always mean big trees Grasses in prairies Cacti in deserts

Timeline of Primary Succession Rocks= 0 years Lichen/Moss= 5 years Simple Plants= 6-8 years Grass & Shrubs= 10-25 years Young trees= 50-100 years Mature trees= 150 years Climax community= 300 years

Secondary Succession Starts with soil Occurs faster and has different pioneer species (simple plants) than primary succession Example: after forest fires or abandoned farm

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http://www.ux1.eiu.edu

http://www.agen.ufl.edu