Community Measurements

Indirect Gradient Analysis o Use Importance Values (Sum of Relative Frequency, Rel. Dominance, Rel. Density)

Indirect Gradient Analysis o Develop Climax adaptation number for each species (By comparing the stands with different leading dominants)

Indirect Gradient Analysis o Those stands the most different are placed at either end o Those most like the extremes are placed close to them o #’s are assigned based on similarity

Indirect Gradient Analysis o Use Importance Values (Sum of Relative Frequency, Rel. Dominance, Rel. Density) o Develop Climax adaptation number for each species (By comparing the stands with different leading dominants) o Continuum Index for stand = ∑Imp. Val. x Climax Adaptation # for each species found in stand o Plot the dominant species with point for each stand (Imp. Value on Y axis; Cont. Index on X)

Distribution & Abundance

Direct Gradient Analysis o Some figure (usually density) plotted against an environmental gradient (such as elevation)

Direct Gradient Analysis o If difficulty in measuring environmental factor: Classify species into ecological amplitude Trees: a)mesic b)submesic c)subxeric d)xeric Values assigned (a=0, d=3) For each stand count individuals in each group Then multiply value X # of individuals in that group. Sum products and divide by total # of individuals o One value for trees & tall shrubs, one for herbaceous plants, then plot values

Continuum classes

Possible outcomes

Gradual vs. Steep (Whittaker) Great Smoky Mtns. Siskyou Mtns.

Ordination o Similar to Gradient Analysis Stands ordered according to composition and abundance, often with cluster analysis o Stands are plotted on a 2-dimensional grid o Values for each stand assigned to environmental factors are then plotted o Look to see trends of factors that correlate with the spread of the stands studied. o Stands may also be plotted geographically

Similarity Index o Coefficient of Community  CC = 2S ab /(S a +S b ) Where: S a = # of species in sample A only S b = # of species in sample B only S ab = # found in both samples o Same formulation as the Bray and Curtis Similarity Index (simply different terms used)

Old Growth Forests - LS Index o 200m X 10m plots (or transect taken) o Count trees over 16”dbh and trees with lichen (Collema or Leptogium) Northern Hardwood Index

o LS index then places the stand in one of the categories seen here

Species Diversity o A measure of richness and eveness o Richness: Number of species Margelef’s: (S-1)/log N o Reciprocal of Simpson’s index 1/∑p i 2 More responsive to abundant species o Shannon index -∑p i lnp i More responsive to rare species