measurements were made of the 12 trees of each species on the hummock. Two ash, five
bay, and five cypress trees were found off the hummocks. Tree measurements at the Iluka
site were limited to diameter at breast height due to the extreme height of the trees.
Height was not estimated for these trees.


VEGETATION MEASUREMENT

 No species were initially planted on the Agrifos or Cargill hummocks to observe
 colonization. Plants were identified, and a percent cover for each species within a 0.25m2
 circular quadrat was given. Four quadrats on each hummock were counted during each
 sampling period. Two quadrats were placed along the top of the hummock in lower
 moisture condition, and two were placed along the slope of the hummock at the soil/
 water interface. Quadrats were placed in similar places on each hummock. Quadrats were
 placed at 18 points off the hummocks in the Agrifos wetland, 12 points in the Cargill
 wetland, and five points in the Iluka wetland to compare vegetation in differing growing
 conditions. Off hummock quadrats were randomly located. Quadrat sampling points were
 marked with 30.5cm sections of PVC pipe on the hummocks and with 90cm sections of
 PVC off the hummocks. The numbers of species (s) were counted as a simple diversity
 measurement. The percent cover (Ci) for each species (Brower and others 1990) within
 the quadrat was determined.

 Percent Cover- Ci = ai / A 100 [6]
 ai = total area covered by a species
 A = total area sampled

 The richness and relative coverage was correlated to show the value of each species in
 the hummock community. The Shannon diversity index (Brower and others 1990) was
 used to determine diversity as each quadrat is considered a random sample of the entire
 community.

 Shannon Diversity Index- H' = -Zpi*logio (pi) [7]
 H' = Shannon diversity
 pi = n/N
 N = number of individuals total
 ni = number of individuals in a given species

Because understory vegetation was not sampled by individual, relative coverage was used
to determine pi by calculating the probability a species would be sampled in a quadrat.

 Weighted Probability pi = P/ P [8]
 where P = ni/n
 P = probability a species will be sampled
 n = total number of quadrats
 ni = number of times a species is sampled


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