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Forests and their Interactions

Forests and their Interactions. AP Environmental Science. Types of Forests. Any area where trees cover more than 10% of land. Includes: open savannas - < 20% ground cover Closed canopy forest – tree crowns overlap to cover most of the ground.

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Forests and their Interactions

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  1. Forests and their Interactions AP Environmental Science

  2. Types of Forests • Any area where trees cover more than 10% of land. • Includes: • open savannas - < 20% ground cover • Closed canopy forest – tree crowns overlap to cover most of the ground. • Primary forests: composed primarily of native species

  3. Reason why old forests are important? O.F. contain unique biological features w/: • large live & dead trees • a large variety of vegetation, insectsand animals species. • Often home to rare species, threatenedspecies and endangered species of plants and animals, making themecologically significant.

  4. Types of Forests-Old Growth Other names include: • Virgin forests • Primary forests • Ancient forests • Primevil forests

  5. Old Growth Forests

  6. New Growth Forests

  7. New Growth forests

  8. Deforestation & Consequences Cause of deforestation? Consequences!! Erosion Water Runoff Excess CO2 Loss of biodiversity Loss of cultural & historic values • Logging industry • Cattle ranching • Farming • Biofuel production • Food production (ie. palm oil)

  9. Forest Canopies • Upper canopy • Mid-canopy • Lower Canopy • http://www.canopyintheclouds.com/panos/elfinforest

  10. Forest Fires • Forest Fire Management • Nova Fires by Month 2000

  11. Forest Fires-Hot Question • In Mediterranean climates like portions of California, a wetter than normal winter often leads to greater severity of fires following summer. This paradox occurs because increased rain leads to… • A. Greater accumulation of chaparral biomass • B. Higher pollination of annual flowers • C. Greater recreational use of parklands • D. Greater erosion & damage to access roads • E. Decreased summer rainfall

  12. Forest Protection Legislation 1. Debt for Nature Swap • Roadless Rule – Clinton Administration • Northwest Forest Plan to regulate harvesting on about 9.9 million ha of federal lands in Oregon, Washing and northern California.

  13. Question to ponder? • The largest area of old-growth forest in the United States is located in: • Alaska • B. Montana • California • North Carolina • Michigan

  14. Forest and Competition • There are several species interactions within an ecosystem: • 1. Competitive Exclusion Principle • 2. Resource Partitioning • 3. Ecological Niche

  15. CompetitionBetween Species • may occur when 2 or more species in community use similar resources & those resources are in short supply OR • - may limit the population growth of the competing speciesIntraspecific Interactions • Relationships within the same species • This type of interspecific competition:

  16. 1. 1. Competitive Exclusion Principle • Experiment #1: Russian ecologist G. F. Gause studied the effects of interspecific competition in two closely related species of protists called Paramecium.What do these results tell you about the interaction of these 2 species? Separate cultures Combined cultures P. aurelia P. caudatum

  17. From his research, Gause concluded that two species so similar that they compete for the same limiting resources cannot coexist in the same place for any length of time. • One species will always be more efficient and adaptable:….in getting food….in reproducing • Ecologists called this concept the • competitive exclusion principle

  18. Ecological Niche: a. Sum total of a species’ use of biotic and abiotic resources in its environ & b. A species’ habitat & it’s job (ex. Forest / producer) • We can now restate the competitive exclusion principle as follows: Two species cannot coexist in a community if their niches are identical.

  19. Resource Partitioning- Experiment #1:Explain this example of resource partitioning. How have the different species adapted to their competition? A. ricordii A. ricordii A. insolitus A. distichus A. insolitus A. aliniger A. christophei A. distichus A. christophei A. distichus A. cybotes A. cybotes A. etheridgei A. etheridgei Figure 19.7 A. insolitus

  20. 2. Resource Partitioning • There are two possible outcomes of competing species w/ identical niches (not just living in the same area) • 1. Extinction of one species • 2. Evolution of one species to use a • different set of resources • Resource partitioning is the differentiation of niches that enables similar species to coexist in a community.

  21. Reproductive Potential …Is an organism’s ability to grow at the fastest rate. (To replenish the species—innate!)

  22. R-selected Hint: Rapid Repro Early reproduction Short life span Hi mortality Little/no parental care Large # of offspring produced 2. K-selected Hint: Longer Repro Late reproduction Long life span Low mortality High parental care Small # of offspring produced REPRODUCTIVEPOTENTIAL COMPARISON

  23. REPRODUCTION TYPES R-SELECTED TYPES K-SELECTEDTYPE

  24. Reproduction Connection • Which of the following is generally true of a K-strategist species? • A. They reach sexual maturity faster. • B. They have more young. • C. They are likely to be invasive species. • D. They have longer life spans. • E. Their populations cycles are more rapid.

  25. The Complexity of Community Networks • The interrelatedness of interactions between species makes communities complex Recruitment Release of volatile attractants Chemical in saliva Wounding Detection by plant Figure 19.17

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