1. Community ecology Outline: Community structure: attributes Factors influencing the structure of communities Community dynamics Chapter 16-18

3. Community attributes # of species Relative abundance of species Nature of species interactions (food webs) Physical structure

4. Community structure Species richness (# of species within community) 10

5. Community structure Relative abundance (% each species contributes to the total number of individuals)

7. Stand one Stand two

8. Simpson’s diversity index D = 0 - 1 –0: high diversity –1: low diversity Stand one (Table 16.1): D=0.13 Stand two (Table 16.2): D=0.36

9. Dominance Yellow-poplar

10. Food webs

12. Keystone species

13. Functional groups Feeding level Exploitation of common resources (guilds) Photosynthetic pathway Shade tolerance Life history

14. Physical structure

16. Zonation

18. supratidal intertidal subtidal

22. Association Relatively consistent species composition Uniform general appearance Distribution that is characteristic of a particular habitat

23. Organismic concept of communities

24. Continuum concept of communities

25. Factors controlling community structure

26. Fundamental niche

29. Species interactions

31. Keystone predation

32. Apparent competition

33. Indirect commensalism

34. Top-down vs. bottom-up control

36. The number of trophic levels regulates plant, herbivore and carnivore numbers B/comp: numbers limited by availability of resources (bottom-up regulation). Competition strong, predation weak. T/pred: numbers limited by predation (top-down regulation). Competition weak, predation strong. # trophic levels:

37. Stress tolerance and competition

38. Smooth cordgrass Salt meadow cordgrass Black needle rush

39. Environmental heterogeneity

41. Relationship between the number of plants per 300m 2 plot beside the hood river, NWT, and an index (ranging from 0 to 1) of spatial heterogeneity in abiotic factors associated with topography and soil. More spatially heterogeneous plots had higher species richness.

43. Environmental quality

44. Plant species diversity in a control plot and a fertilized plot in the Parkgrass experiment in Rothamstead, England. Fertilized plots have lower species diversity. The Parkgrass experiment, which began in 1856, is the longest running ecological experiment.

45. Community stability Types of stability: 1.Resilient community: returns to former state after disturbance 2.Resistant community: changes little in response to disturbance

46. Community dynamics: Succession

47. Pioneer species Late successional species Primary succession

48. Secondary succession

49. beach grassshrubspinesoak

50. Primary succession: newly exposed substrate

51. Dryas sp. An early succession species on glacial moraines in Glacier bay. Dryas is a symbiotic N-fixing plant

52. Populus trichocarpa Salix arctica After Dryas, cottonwood and willows become established

53. Alnus incana Alders become the dominant tree after 50 years

54. Tsuga mertensianaPicea sitchensis “Climax”: mixed spruce-hemlock forest

55. Secondary succession: after disturbance

58. Density Autogenic vs. allogenic change

61. Allogenic environmental change

62. Oak-pine forest Species diversity during succession

63. Intermediate disturbance hypothesis

64. HighLow

65. In New Zealand streams, less disturbed sites support more complex communities (i.e., communities with larger, more connected food webs)

66. Bark beetle/wood- boring beetle Fungi/bacteria Predatory insects Moss and lichen Invertebrates/ mice/ salamanders Succession of heterotrophs

68. Changes over geologic time

71. Concept of community revisited