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

Count Intolerant Taxa to Suspended Solids and Sediments (SSS) was significantly correlated with total
plant richness, native plant richness, mean plant conservatism, mean native plant conservatism, mean
specific conductivity, ammonia-NH3, total nitrogen, dissolved nitrogen, available N:P ratio, atrazine
metabolite desethylatrazine (DEA), metribuzine, cyanazine, and Number of Herbicides Detected.
Robust regression analysis of Count SSS Intolerant Taxa and the stressor variables in Table 13 showed
that NH3 and Number of Herbicides Detected as the only significantly correlated variables. The
equation explained about 36% of the observed variance in the Count SSS Intolerant Taxa metric.
Count SSS Intolerant Taxa = 4.284377+ 12.98026 × NH3 (µg/L) – 384267
× Number of Herbicides Detected
The Macroinvertebrate Multiple Metric Index (MMI)
The above metrics were determined to be useful for assessing the biological condition (i.e.
integrity) of the lower Missouri River floodplain wetland study population and were combined in
a multiple metric index (MMI). In the metric development process, scoring the index is the most
simple and straight forward task. Because both Stoddard et al. (2008) and Chipps et al (2006)
referenced the continuous scoring technique for multi-metric indices described by Blocksom
(2003), the following scoring calculation adapted from Minns et al. (1994) was used for metrics
that increase in value (indicating positive wetland quality) with decreasing disturbance (Chipps
et al. 2006):
Ms = Mr/ Mmax x 10
Where Mr is the raw metric score and Mmax is the maximum score found in the sample
population, and Ms is the resulting individual metric score for each sample. Metric values that
increase with increase disturbance, meaning those that indicate negative wetland quality, were
calculated as:
Ms‟ = 10 - (Mr/Mmax *10)
The final multiple metric score for each site was calculated as:
MMI = (ΣMsi/n) * 10
Msi are the individual metric scores and n is equal to the number of individual metrics used to
calculate the final index (Table 14 - Table 16).
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