Principles of Vegetation Measurement & Assessment
and Ecological Monitoring & Analysis

 
Veg Sampling
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Detailed Calculations for Shannon Wiener Index

Avg. plants/m2

                
UPLAND SITE

 n

 n/N   ln of (n/N)   n/N*ln(n/N)      
Greasy Grass 3 0.333 x -1.099 = -0.366      
Fuzzy Forb 3 0.333 x -1.099 = -0.366      
Spiney Shrub http://www.cnr.uidaho.edu/veg_measure/Modules/Lessons/Module%207/Pix/Shannon_W.gif
3
0.333 x -1.099 = -0.366      
SUM = 9  = N       -1.099  = ∑ or sum  
            1.099  = H'
 or Shannon Weiner Index
            Value becomes positive because of
  negative sign in formula
Avg. plants/m2
LOWLAND SITE

 n

 n/N   ln of (n/N)   n/N*ln(n/N)      
Greasy Grass 7 0.778 x -0.251 = -0.195      
Fuzzy Forb 2 0.222 x -1.504 = -0.334      
Spiney Shrub 0                
SUM = 9        
-0.530
 = ∑ or sum  
            0.530  = H'
or Shannon Weiner Index

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Detailed Calculations for Simpson's Index

  Avg. plants/m2          
UPLAND SITE

 n

 n-1 n(n-1) n(n-1)/ N(N-1)    
Greasy Grass 3 2 6 0.083    
Fuzzy Forb 3 2 6 0.083    
Spiney Shrub 3 2 6
0.083
   
SUM = N = 9     0.167  = ∑ or sum = λ 
N(N-1) = 9 x 8 = 72     = Simpsons Index
Avg. plants/m2    
LOWLAND SITE

 n

 n-1 n(n-1) n(n-1)/ N(N-1)    
Greasy Grass 7 6 42 0.583    
Fuzzy Forb 2 1 2 0.028    
Spiney Shrub 0    
 
   
SUM = N = 9     0.611  = ∑ or sum = λ 
N(N-1) = 9 x 8 = 72     = Simpsons Index

>> Return to Diversity Estimate Page