1. Classification of communities
And now,
for something completely different....
Classification of communities

2. Association analysis 4 major approaches: 1) Tabular methods
2) Cluster analysis
3) Association analysis
4) Ordination methods

3. Cluster analysis Expresses similarity of stands graphically (2 D)
Similarity? Coefficient of Community (CC)
CC: how close composition is b/w samples

4. Cluster analysis 2 major indices:
Jaccard’s Index
Sorensen’s Index
Presence or cover (“weighted by cover”)
Values: from 100 (same) to 0 (no sp. in common)

5. Cluster analysis
Generate dendrogram (tree diagram showing similarities)
Y axis = “resolving power:” 40

6. Cluster analysis Decide level similarity: Result: associations
CC = 10 (threshold III): 2 associations
CC = 20 (threshold II): 7 associations
CC = 30 (threshold I): 15 associations
Result: associations

7. Association analysis 4 major approaches: 1) Tabular methods
2) Cluster analysis
3) Association analysis
4) Ordination methods

8. Association analysis Uses differential spp. (influence on other spp.)
How document? Use contingency table analysis

9. Association analysis Contingency table analysis
Calculate chi-square for every pair sp. (all samples)
Old
Lab
Exercise

10. Association analysis Matrix chi-square values Species Species A B C D
A X
B X
C X
D X
Total

11. Association analysis Species Species A B C D A X 57 12 23 B 57 X 17 3
C X
D X
Total
Select sp. w/ highest chi-square total
Split stands into 2 groups: w/ A & w/o A

12. Association analysis Repeat on each split group
1 sp. A present
Other lacks sp. A
Continue subdivide until total chi-square < some number

13. Association analysis Ex, 70 quadrats in salt marsh
Association analysis: use until total chi-square = 7

14. Association analysis
Dendrogram (70 quadrats)

15. Association analysis 8 groups: presence/absence sp. +32, +38 = group 1
Etc.
Group =
association

16. Association analysis
Summary: Associations defined

17. Classification of communities
4 major approaches:
1) Tabular methods
2) Cluster analysis
3) Association analysis
4) Ordination methods

18. Ordination Methods
Plant
Ecology
Theatre!
Not that kind of ordination…

19. Plant Ecology Theatre Reg: Trouble at t’mill
Lady M: Oh no! What sort of trouble?
Reg: One on’t cross beams gone owt askew on’t treddle.
Lady M: Pardon?
Lady M: I don’t understand what you’re saying.
Reg: One of the cross beams has gone out of skew on the treadle.
Lady M: What on earth does that mean?
Reg: *I* don’t know! Mr. Wentworth just told me to come in here
and say that there was trouble at the mill, that’s all. I didn’t
expect a kind of Spanish Inquisition!
Nobody expects
the Spanish
Inquisition....

20. Ordination Methods
Data graphical
“ordination space”

21. Ordination Methods Associations based on dominants
Correlate vars. w/ axes:
4 methods

22. Ordination Methods (4) 1) Principal Components Analysis (PCA)
(called components)
Axes

23. Ordination Methods Ex, PCA output: 60-stand by 30-species matrix
Can plot spp. (LITU=Liriodendron tulipifera, QURU=Quercus rubra)
PCA-1 correlates w/ stand age (open circles=young stands)
Open=young
stands

24. Ordination Methods (4) 2) Detrended Correspondence Analysis (DCA): DCA
PCA

25. Ordination Methods (4) 3) Nonmetric Multidimensional Scaling (NMDS):
Vectors: correlations w/ env. vars. (show direction)
K=soil potassium
BA=basal area
DEN=tree density
NO3=soil nitrate
Open=young
stands

26. Ordination Methods (4) 4) Canonical Correspondence Analysis (CCA):
Vectors: relate vars. (length = strength influence of var.)
CEC=soil cation exchange capacity
SAND=amt sand in soil
OM=soil organic matter
BA=basal area
DEN=tree density
NO3=soil nitrate
Open=young
stands

27. Ordination Methods
Dominant

28. Remote sensing

29. Remote sensing
Reflectance info:

30. Remote sensing Can measure: protein, lignin,
Mapping conifers killed by
bark beetles in Canada

31. Remote sensing
Involves ground truthing:

32. Vegetation mapping
Vegetation:

33. Vegetation mapping National Vegetation Classification System (U.S.)
Hierarchical classification (Division largest, Association smallest units)
Physiognomy important:
Floristics important:
USA! USA!

34. Vegetation mapping
Ex: Populus deltoides/Salix woodland

35. Vegetation mapping
Use GIS (geographic information system)

36. Vegetation mapping What map? 1) Actual vegetation Ground truthing
needed to
verify patterns

37. Vegetation mapping
2) pre-human vegetation: aka Potential vegetation

38. Vegetation mapping Early explorers Ex, William Bartram
SE US early 1700s