Changes in Communities: Ecological Succession

1. Changes in Communities:Ecological Succession

2. Ecological Succession • The natural, gradual changes in the types of species that live in a particular area • The gradual replacement of one plant community by another through natural processes over time

3. Primary Succession • Begins in a place without any soil • Sides of volcanoes • Landslides • Flooding • Starts with the arrival of organisms that do not need soil to survive, such as lichens. • Called PIONEER SPECIES

5. Primary Succession • Soil starts to form as lichens and the forces of weather and erosion help break down rocks into smaller pieces • When lichens die, they decompose, adding small amounts of organic matter to the rock to make soil

7. Primary Succession • Simple plants like mosses and ferns can grow in the new soil

8. Primary Succession • The simple plants die, adding more organic material • The soil layer thickens, and grasses, wildflowers, and other plants begin to take over

9. Primary Succession • These plants die and they add more nutrients to the soil • Shrubs and trees can now survive

10. Primary Succession • Insects, small birds, and mammals have begun to move in • What was once bare rock now supports a variety of life

11. Secondary Succession • Begins in a place that already has soil and was once the home of living organisms • Occurs faster and has different pioneer species than primary succession • Example: after forest fires

12. Secondary Succession On Abandoned Farmland

13. Two Types of SuccessionFrom http://www.geowords.org/ensci/imagesbook/04_03_succession.swf

14. 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

15. Invasive Species Defined as a species that is: • non-native (or alien) to the ecosystem under consideration. • whose introduction causes or is likely to cause economic or environmental harm or harm to human health. • Invasive species can be plants, animals, and other organisms (e.g., microbes). • Human actions are the primary means of invasive species introductions.

16. Eastern Red Cedar:An Invasive Species • Eastern Red Cedar invasions create a forest canopy which out-competes native vegetation for sunlight and water. • The resulting bare soils and increased erosion severely impact native plants and animals. • How are humans responsible?

17. A Local Example Southeast corner of 135th & Quivira