1. Systems Approach

2. Ecosystem Community Population

3. Ecosystem Landscape

4. Community -Populations of different species that interact. Ecosystem - the various communities of organisms interacting with the environment. Landscape -a physical area such as a watershed consisting of various landscape elements (fields, forests) and the species found.

5. Community Species richness Species diversity Functional groups Life Forms Trend Analysis Statistical Approach

10. Ecosystem Energy Flow Nutrient cycling

13. Landscape Spatial Arrangement of landscape elements or units.

14. Community Central Question: How is a community structured and by what?

15. Are there patterns in community structure? If so, what has caused this pattern Competition Predation Time Size of patches (islands)‏

16. Equilibrium Non-equilibrium

17. Equilibrium - focus on the mean

18. Non-equilibrium - focus on the variation

19. Equilibrium Non-equilibrium Mean Variation Predictability Unpredictable Competition Island Biogeography Disturbance Succession

20. Competition An equilibrium concept.

21. Data from Gause 1934

24. Competition is often not an important structuring process in communities.

25. Species area relationship Preston (1948, 1960 and 1962)‏ –S = CA z –log S = (log C) + z(log A)‏

26. Island Biogeography 2 processes - extinction and colonization Function of – island size and distance from mainland.

29. Succession

30. -fire, insect damage, wind, flooding -unpredictable in space and time -results in non-equilibrium dynamics -recognized as being central to ecosystems Disturbance a non-equilibrium concept

31. Modeling Disturbance

32. Intermediate Disturbance Hypothesis Predator Mediated Co-existence Hyp.

33. Effect of grazing on species richness

36. Succession In the Boreal Forest

37. Holling’s Four-Box Model of ecosystem function.

38. Keystone Species

40. Other Keystone species: - Beaver (create ponds)‏ - Elephants (Trees)‏ - Sea otter (Seaurchins)‏

41. Community structure Equilibrium and non-equilibrium AND Time.

42. Complexity Stability Complexity

43. Complexity Stability Debate Elton Complexity -> Stability May 1970’s Modeling – Not so! Subsequently refuted (late 80’s & 90’s)‏ Yodzis - modeling –Tillman – experiments –BUT we still did not understand the nature of stability

44. Summary Populations –movement –Fragmentation –Spatially structured populations Communities –Dynamic equilibrium/non-equilibrium –Competition –Island Biogeography Protected areas - corridors –Disturbance Intermediate disturbance hypothesis predator mediated co-existance Ecosystem stability