Volumetric Water Content


 Volumetric water contents (one expression of soil moisture) of hummock soils
 can be used as an indication of the available microhabitats for vegetation growth. Figures
 5.11-5.15 have the volumetric water content plotted against hummock elevation for each
 soil type in the Agrifos wetland for each sampling period. A best-fit line has been drawn
 through each group of points, and an r2 value determined. A steeper slope of the best-fit
 line indicates a higher range of moisture values from the highest elevation to the lowest.
 In each sampling period, the organic soils have the steepest slope and therefore the
 highest range of moisture from the lowest to highest elevation. Overburden hummocks
 appear to have the shallowest slopes, indicating a more even distribution of moisture
 from lowest to highest elevation. From the first to the last sampling period, the r2 values
 steadily increase for each soil type throughout 1999. Organic soil values increase from
 0.58 to 0.87. Sandy soil values increase from 0.37 to 0.88. Overburden soil values
 increase from 0.33 to 0.92.

 Figures 5.16, 5.17 and 5.18 show the volumetric water contents plotted against
 elevation for the hummocks in the Cargill wetland. The organic soils and overburden
 soils have similar slopes, indicating close ranges in moisture values. The increasing r2
 values are again seen for these soil types in 1999. The organic values increase from 0.35
 to 0.75, and the overburden values increase from 0.47 to 0.81.

 Figures 5.19-5.23 show the average volumetric water content for each hummock
 in the Agrifos wetland. The maximum and minimum values for volumetric water content
 are also plotted to show the range of micro-sites. A line has been drawn connecting the
 average values to show the trend for each soil type. Figure 5.19 presents data from the
 first sampling period. The organic hummocks, plotted in the middle of the graph, have
 higher averages and wider ranges of water contents than overburden and sand hummocks.
 Overburden hummocks have higher averages than the sand hummocks. The overburden
 hummocks also appear to have a similar width of ranges as the sand hummocks, but with
 higher minimum and maximum values. The same trend appears in each of the next three
 figures, which contain data for the other sampling periods.

 Figures 5.24. 5.25 and 5.26 show similar data from the Cargill wetland. Again,
the trend shows organic hummocks to have higher average volumetric water content than
the overburden hummocks. Organic soils also have a wider range of values than the
overburden soil, indicating more available micro-sites for vegetation.


HUMMOCK TO OFF-HUMMOCK COMPARISON


Species Diversity

 The ability of hummocks to provide microhabitat for vegetation growth not found
in other areas of a wetland would be a major attraction of incorporating hummocks into


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