laurifolia was the next most common species and was found in thirty-six percent of the
sites. Ten of the fourteen sites had seedlings or saplings of subcanopy species present;
however, no site had more than 2 species occurring. Shrub seedlings or sapling occurred
in all sites sampled except LP2 Phase 1, the youngest site. Vines occurred in all but the
two youngest sites. The greatest number of vine species (11) occurred in Sink Branch
(18 years).

 Species diversity in the understory ranged from 1.08 to 1.57. Species evenness
 neared unity for all sites (0.90 to 1.0) and was less than 0.90 in only one site (0.86 at
 SP6).

 The understory community status is provided in Table 7.10. Those sites with the
 lowest "Understory Community Wetland Status" contain a greater probability of
 sampling wetland species and perhaps a greater probability of being a wetland. Figure
 7.7 is a graphical representation of community wetland status. The horizontal line in
 Figure 7.7 represents the average "Understory Community Wetland Status" of all sites
 sampled. Six of the research sites have a lower than average status suggesting that they
 have a greater likelihood of supporting wetlands plants. However, it is understood that
 just being wet does not necessarily indicate a quality wetland.

 Figure 7.8 shows the number of obligate, facultative wetland and facultative plant
 species along transects in several research sites. These figures identify areas along the
 transect where the plant community is dominated by obligate wetland species. They also
 identify transects where facultative upland species outnumber wetland species. Notice
 that although East Lobe falls above the line in Figure 7.7, the plant wetland status along
 each of two transects (Figure 7.8b) shows a dominance of obligate, facultative wetland
 and facultative plant species. The center section of transect 1 corresponds to a
 topographic low, which results in water levels that may restrict vegetation establishment.

 Figure 7.9 shows the probability of sampling understory species under varying
levels of light transmittance. Frequency of occurrence under each of ten light
transmittance class ranging from 0-10% to 90.1-100% transmittance were calculated for
all understory species occurring in at least ten quadrats. This represents the frequency of
occurrence of a species below 1 meter; it does not include the occurrence of trees or
shrubs greater than one meter. Acer sp., Apios sp., Clematis sp., Galium sp., Rubus sp.,
Sambucus sp. and Urena lobata more frequently occurred in lower light transmittance
classes. In contrast, Typha sp. and Pontedaria cordata occurred more frequently in areas
with greater light transmittance. Unexpectedly, Ludwigia peruviana and Mikania
scandens occurred more frequently in lower light transmittance levels perhaps, as a result
of control measures such as herbiciding or hand removal.


Frequency of Occurrence of Species in the Understory

 Table 7.11 lists the frequency of occurrence of species of all structural categories
in the understory. This provides insight into occurrence of regeneration of all structural
categories.


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