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

Total Nitrogen mg/L
Mean Conductivity uS/cm
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Study Phase
Chlorophyll a ug/L
Herbicides Detected
Figure 45. Median box plots of water quality parameters that were significantly different
between study populations for (a) log total nitrogen mg/L, (b) log chlorophyll-a, (c) log mean
conductivity mS/cm, and (d) the number of herbicides detected. Box area represents inner
quartile range, while “whiskers” represent the upper and lower observations.
All metrics that discriminated between the identified a priori groups in the metric selection
process were tested for congruency with other wetland assessment tools and water quality
parameters using ANOVA or Kruskal-Wallace analysis. Metric scores for percent burrowers,
count of heavy metal (HM) intolerant taxa, and count of taxa intolerant to suspended solids and
sediments (SSS) were the only metrics found to be significantly different between the two study
populations (Figure 46). However, the log transformed mean percent Hydroptilidae was
significantly different (p = 0.004) between study populations suggesting that this metric could
discriminate between the populations if the measurement scale was adjusted (use of log values or
some other transformation). Counts of intolerant taxa to heavy metals and percent burrowers
were normally distributed and were statistically different between populations. Percent
burrowers (mean = 38.7) was significantly lower in reference sample than the random samples
(mean = 54.3). Counts of intolerant taxa to heavy metals were highest in the reference (mean =
17.4) population when tested against the random population (mean = 13.3).
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Study Phase
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