Changes in Ecosystems: Ecological Succession

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

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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 successionprocess • 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.agen.ufl.edu

Changes in Ecosystems: Ecological Succession