Changes in Ecosystems: Ecological Succession

1. Changes in Ecosystems:Ecological Succession

2. Succession Definition: • Natural, gradual changes in the types of species that live in an area.

3. Causes of Change? • Brainstorm with your table ABIOTIC factors that could cause disruption in an ecosystem.

4. What if?

5. What if?

6. What if? • An avalanche?

7. Causes of Change? • Brainstorm with your table BIOTIC factors that could cause disruption in an ecosystem.

8. What if? • Deforestation?

9. Human Development

10. Invasive Species • Thousands of non-native invasive plants and animals have infested millions of acres of land and water across the United States. • These invaders cause massive disruptions in ecosystems by reducing biodiversity and damaging the health of our nation’s ecosystems. They have the capacity to dominate, overwhelm, or wipe out native species. • The financial impact from invasive species infestations in the United States has been estimated at $138 billion per year in total economic damages and associated control costs. Congongrass Burmese Python Kudzu

11. Insects • Nationwide, 70 million acres of public and private lands are at serious risk from insects and diseases • Across the South, one of the biggest forest management challenges is the Southern Pine Beetle. Attacking timber stands throughout the region, it is estimated that 57 million acres are at risk of infestation. From 1999 to the present, the Southern Pine Beetle outbreak has caused timber value losses of over $1.5 billion. • Gypsy Moth Pine Beetle Gypsy Moth, Lymantria dispar (Linnaeus) femalePhoto from USDA APHIS PPQ archives

12. Diseases • Forest pests and disease have seriously harmed the environment and have imposed significant cost to the U.S. economy. • Exotic pests and pathogens, such as the chestnut blight, Dutch elm disease, and beech bark disease have had a profound effect on forests. Annosum Root Disease

13. M-DCC / PCB 2340C There are two main types of Ecological Succession • Primary Succession: The development of an ecosystem in an area with no life before. • Secondary Succession: An ecosystem develops after a disturbance in an area where life has existed before.

14. Primary Succession Example: • Cooling lava from a volcano forms a new island. M-DCC / PCB 2340C

15. Primary Succession • Begins in a place without any soil • In the beginning there is only rock, sand, volcanic ash. • Since there is no soil, there is no community. Where does the soil come from?

16. M-DCC / PCB 2340C Primary Succession

17. In order for there to be soil there must be nutrients like nitrogen. So … why is there no soil?

18. Primary Succession • Lichens begin growing on the rocks. Over many years lichens break down rock into sand. • Weathering and erosion break down rock into sand.

19. Primary Succession • Lichens that do not need soil to survive • Called PIONEER SPECIES • (Why? What is a “pioneer”?)

20. Primary Succession • Lichens grow larger. Some die. Decomposers arrive and break down the lichens. The dead lichens and waste materials of the decomposers enrich the sand. Nitrogen cycle begins. Eventually enough nutrients enter the sand and it becomes soil.

21. http://www.life.uiuc.edu

23. Intermediate Species • Seeds are blown in by the wind or carried in by animals. Simple plants like mosses can grow in the new soil • The plants grow and the soil gets enriched as plants die..

24. Intermediate Species • Herbs and weeds can grow in the thicker, enriched soil

25. Intermediate Species • 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

26. Intermediate Species • Medium sized animals and birds make this their habitat. • The vegetation grows closer together, reducing the amount of space available for growing. • Competition between lichen and shrubs for the same space. Eventually one species (lichen) will die out (or move) and the other species will survive (shrubs).

27. Intermediate Species • These plants die, and they add more nutrients to the soil • Shrubs and tress can survive now

28. Intermediate Species • 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

29. M-DCC / PCB 2340C Primary Succession

30. These plants die, and they add more nutrients to the soil • Now larger trees can grow: Beech, Oak, Walnut, Maple…

31. Effects on Biodiversity? • Brainstorm with your table how biodiversity changes as an area undergoes succession.

32. M-DCC / PCB 2340C The Climax Community • A climax community is a mature, stable community that is the final stage of ecological succession. • In an ecosystem with a climax community, the conditions continue to be suitable for all the members of the community. • Every region has its own set of climax species, which are the plants that are best adapted for the area and will survive after succession has finished, until another disturbance clears the area.

33. These are Climax Communities M-DCC / PCB 2340C

34. 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

35. Threats to Climax Communities • Forest Fires • Humans building cities and roads • Flooding, Volcanic eruptions • Clearing a community for agricultural purposes • Anything that destroys the existing community, but much of the soil remains. Sometimes, some of the organisms remain as well.

36. Secondary Succession

37. Secondary Seccession

38. Secondary Succession • Organisms are destroyed but the soil is safe. • The soil already contains the seeds of weeds, grasses, and trees. More seeds are carried to the area by wind and birds. • Succession begins again but the primary species are different. • Because soil is present, this succession is faster.

39. Ecological Succession • N

40. Secondary Succession on an Abandoned Cornfield

41. Secondary Succession • 1. Some seeds in the soil begin to grow.

42. Secondary Succession • Larger shrubs move in.

43. Secondary Succession • 3. Fast growing trees (such as pines) move in • 4. These are followed by slower-growing hardwood trees

45. Ecological Facilitation • In some communities, species interact in ways where some benefit is received without harm to either species. • Examples: • Mutualism – both species benefit • Commensalism – One species benefits, neither is harmed

46. Why would species “help” each other? • Protection from predators (clownfish and anemones) • To reduce competition (sea urchins eat kelp which reduces competition between the kelp for light)

47. Why would species “help” each other? • Protection from stress (seedlings growing in shade) • Access to resources (bromeliads grow on tree branches to reach light)

48. Why would species “help” each other? • For transport or to transport genetic material (Like pollen or seeds)