1. Chapter 16 Species Abundance and Diversity

2. 1st Question of the Day Define the term “Community”

3. 1st Question of the Day Define the term “Community” An association of interacting species inhabiting some defined area.

4. Chapter 16 Species Diversity Objectives: 1.Identify the abundance distributions of species in a community 2.Determine objective measures of species diversity 3. Determine how many species there exist in the world 4. Identify trends in species diversity distribution 5. Relate the concepts of diversity and stability

5. Log-Normal Pattern of Species Abundance In Communities Very few species have extremely high relative abundance Why ? Low ◄ Abundance ► High (Log Scale) Number of Species

6. Log-Normal Pattern of Species Abundance In Communities Very few species have extremely high relative abundance Very few species have extremely low relative abundance Most species are moderately abundant Plants Birds Low ◄ Abundance ► High (Log Scale) Number of Species

7. Species Abundance Log normal distributions are thought to be a consequence of species in a community subdivided niche space. What does this mean?

8. Species Richness How many species exist in the world? E. O. Wilson found 1.4 million classified Most ecologist agree 3-10 million E. O. Wilson estimates 100 million Problem!!!! Hard to measure (or find) the dang critters!!!

9. Species Richness Terry Erwin: Tropical rain forest insects

10. Species Richness 30 - 40m

11. Species Richness Bug Bomb to the tree tops----

12. Species Richness Bug Bomb to the tree tops---- Funnels to catch Insects as they fell---

13. Terry Erwin

14. Species Diversity Erwin’s results 163 species of beetles in one species of tree Luehea seemannii Estimated 50,000 tropical tree species If this typical - then 8,150,000 canopy dwelling tropical beetles Beetles represent 40% of arthropods

15. Species Diversity In tropical canopy - 20 million species arthropods Twice as many arthropods in canopy as on the ground - 30 million tropical species Conclusions: From 163 beetles - expanded to 30 million arthropod species in tropical rain forests

16. Species Diversity Stork - Similar techniques to Erwin Indonesia 10-80 million species on earth

17. Species Richness How many species exist in the world? E. O. Wilson found 1.4 million classified Most ecologist agree 3-10 million E. O. Wilson estimates 100 million

18. Species Diversity Bacteria: Pinch of soil - Quarts grains decaying organic matter free nutrients 10 billion bacteria

19. Species Diversity Pinch of soil - 1/1,000,000 of the pinch Spread out on agar plate and grow - expect 10,000 bacterial colonies How many do we see? 10-100 colonies

20. Species Diversity Bacteria: Bergey’s Manual of Systematic Bacteriology 4,000 species of bacteria How many exist? Unknown, and limited by technology to grow them.

21. Species Diversity Definition: 1. A measure of the number of species (species richness) and 2. The relative abundance (evenness) within a community.

22. Species Diversity Low Diversity: either few species or highly uneven abundances High Diversity: large number of species or very even abundances

23. Fig. 16.5

24. Species Diversity AAAAABCDABCD AAAAAAAADCBA AAAA AAAABCAD AAAAAAAACDAB

25. Species Diversity AAAAABCDABCD AAAAAAAADCBA AAAA AAAABCAD AAAAAAAACDAB LowestHighestDiversity Shannon-Weiner Index Pages 374-375 Table 16.1

26. Species Diversity Some Assumptions -Species Diversity Indices 1. All species have equal impact on the community 2. No account made for variation within a species (e.g., larvae or adult)

27. Species Diversity Some Assumptions -Species Diversity Indices 3. Species accounts can be taxonomically difficult 4. Cannot compare different communities (e.g., plankton and fish, tree and insect)

28. Species Diversity OK-- We can’t measure all the species in the world (at least not at the moment) But!!! Can we get some guidance or hints where biodiversity is greatest???

29. Species Diversity More land area to develop and no barriers to spread of species Biodiversity Hotspots

30. Latitudinal Trends at Different Latitudes 8 40 72 Latitude Number of species 75 50 25 Quadrupedal Mammals (4 legged furry things!) Muncie

31. Species Diversity Why? Three reasons----------

32. Species Diversity 1. With environmental (habitat) heterogeneity, species diversity increases, compared to uniform environments - greater niche differentiation and resource partitioning

33. Species Diversity Environmental heterogeneity: can be defined as "with parts that are different". Resource partitioning: avoidance of, or reduction in, competition for similar resources by individuals of different species occupying different nonoverlapping ecological niches

34. Foliage Height and Bird Species Diversity

35. MacArthor’s warblers Fig. 16.9

36. Species Diversity Variant nutrient (and moisture) availability

37. Variation in Nitrate and Soil Moisture Different plant species are the superior competitor under different soil conditions. Complex environment prevents competitive exclusion.

38. Variation in Soil Conditions Is Associated With Variation In Species Composition of Plant Communities. Fig. 16.14

39. Species Diversity 2. Nutrient Availability: High species diversity occurs in environments with LOW nutrient availability. In high nutrient environments, competition for LIGHT dominates. Competitive exclusion is more likely to drive some species extinct.

40. Soil Fertility and Plant Species Diversity (Rain Forest in Ghana, Africa)

41. Species Diversity 3. Disturbance:

42. Question for the Day! What level of disturbance (e.g., fire, drought, local condo development, etc.) would be associated with the highest and lowest diversity levels? Pick from low, medium, and high disturbance levels. Of course, defend your answer---------

43. Fig. 16.18

44. Species Diversity - Who Cares? Principle of Community Ecology: Diversity and stability are causally related. More Stable Less Stable

45. Species Diversity Why? 1. Increasing species diversity leads to more complex interactions: e.g., more species, more predation, more competition, more parasitism 2. Complex systems are more stable: changes in a single species have less impact

46. Stability Two parts: 1. Resistance - the ability of a system to resists perturbation 2. Resilience - the ability of a system to return to normal following disturbance

47. Species Diversity What if---- An exotic species enters a community. (Presumably) it would immediately increase species richness, but would it increase species diversity overall???????????????

48. Kudzu

49. Zebra Mussels

50. European Starling

51. Nile Perch

52. Summary for Today! 1. Determined abundance distributions and species richness 2. Determined species diversity is a mix of abundance and eveness 3. Identified reasons for levels of species diversity 4. Diversity and stability are related concepts

53. Species Diversity Intermediate Levels of Disturbance - # of Species Frequency or intensity of disturbance Low High