Changes in Ecosystems: Ecological Succession. Definition: Natural, gradual changes in types of...
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Transcript of Changes in Ecosystems: Ecological Succession. Definition: Natural, gradual changes in types of...
Changes in Ecosystems:Ecological Succession
Definition:
• Natural, gradual changes in types of species living in area; can be primary or secondary
• Succession based on changes in plant communities over time.
Primary Succession
• Begins in place w/o soil – Sides of volcanoes where lava flow has
occurred.– Landslides– Flooding
• Step 1: Starts w/ arrival of living things (ex: lichens) - do not need soil to survive
• Called PIONEER SPECIES
http://botit.botany.wisc.edu
http://www.saguaro-juniper.com/
Primary Succession
• Step 2: Soil starts to form
– Weathering & erosion break down rocks into smaller pieces
– Lichens die & decompose - adding small amounts of organic matter (N,P,C) to the rock to make soil
http://www.life.uiuc.edu
Primary Succession
• Step 3: Simple plants (mosses & ferns) grow in the new soil
http://uisstc.georgetown.edu
http://www.uncw.edu
Primary Succession
• The simple plants die, adding more organic material
• The soil layer thickens, and grasses, wildflowers, and other plants begin to take over
http://www.cwrl.utexas.edu
Primary Succession
• Step 4: Lower plants die, adding more nutrients to the soil
• Step 5: Shrubs and tress 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
LAVA FLOWS & PRIMARY SUCCESSION
Secondary Succession
• Begins in a place that already has soil and was once the home of living organisms
• Occurs faster because the land doesn’t have to build up the soil.
• has different pioneer species than primary succession
• Very often occurs after natural disasters such as forest fires, volcanic eruptions involving the spewing of ash.
The Cedar Wildfire was the biggest wildfire in California. It was ignited was caused by a hunter when he lit a flammable shrub called chapparral. These fires burned down about 280,000 acres of land.
2 years after the fire…..
Mt. St. HelensWashington1980’s
http://www.geo.arizona.edu
http://www.ux1.eiu.edu
Climax Community
• A stable group of plants and animals that is the end result of the succession process
Climax Community!
http://www.agen.ufl.edu
Climax Communities are NOT always big hardwood trees such as oaks and maples!!!
Desert Climax Community Beach Climax Community
Grasslands Climax Community Taiga Climax Community