Koontz, J., D.G. Huggins, C.C. Freeman, D.S. Baker - Central Plains ...

Comparisons of data from those few sites that were revisited indicate that temporal and
hydrological differences can affect both abiotic and biotic conditions within these floodplain
wetlands. However, most of this study is based on the comparisons of two populations and the
temporal and spatial variance within individual sites is part of the error that most be accept in
one sample studies of populations.
Disturbance Assessment
A field-level disturbance assessment (DA) score system was developed during these studies
(Appendix D). Initial development began in Phase I and continued through the early part of
Phase II (see Kriz et al. 2007, Beury 2010). The initial field form of the DA was revised for
Phase II and all sites scored with the early version were rescored.
The DA was developed as a Level 2 assessment tool to estimate the possible level of disturbance
a site might be exposed to based on locally observed conditions and factors. The reference
wetland population consistently had lower DA scores than the random population, although
some wetlands in the random population are probably of reference quality. CDFs for DA scores
for each study group clearly show population distinctions up through the 90 percentile (Figure
38).
In addition to scoring both the reference and random population to examine the DA‟s
discriminatory ability we also used the DA to look at other wetland and landscape (i.e.
ecoregions) factors. Only the Phase II wetlands were used in these tests as this population was
thought to be the most variable in terms of levels of disturbance. Disturbance assessment scores
were similar among the ecoregions, though means and standard error measures were slightly
different. Means and standard errors for the final DA were 8 (STDERR = 0.94), 9.8 (STDERR =
1.69), and 10.38 (STDERR = 0.82) for the WCP, IRV, and CIP ecoregions, respectively. No
significant differences were determined among the major wetland classes examined in this study,
but lacustrine scores tended to be higher than palustrine scores. Unconsolidated Bed scores were
significantly lower than Aquatic Beds, but all types were similar in means and variance (Figure
39). Though not significant statistically, mean scores for the UB wetland type were the lowest
among all wetland types. Generally DA scores for each wetland type except MIX followed the
same pattern as FQI and MMI (the macroinvertebrate multimetric index discussed in the next
section) (Figure 39). The DA scores for MIX tend to be high, but the FQI and MMI scores
suggest that the level of impacts are more moderate when compared to the other wetland types.
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