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

quality of plant community, respectively. The floristic quality index is only one component for
assessing the plant community in wetlands. Other factors, such as native wetland plant species
richness, may also indicate the condition of the wetlands health or quality to maintain diverse
communities of invertebrates and vertebrates, including amphibians, water fowl, and small
mammals. In situ water quality measures in this study consisted of mean values for water depth,
Secchi disk depth, water temperature, turbidity (NTU), conductivity (mS/cm), dissolved oxygen,
and pH. Water depth was measured with a surveyor‟s telescoping leveling rod to the nearest
centimeter. Water properties were measured with a Horiba U10 Water Quality Checker. One
liter samples were collected along three imaginary transect lines at right angles to a line
extending along the longest axis of the study wetland and combined in a 5-liter carboy as one
composite sample (Figure 2). Chemical laboratory analysis was conducted on composite water
samples for concentrations of chlorophyll-a, nitrates, nitrites, ammonia, total nitrogen, total
phosphorus, total and dissolved organic carbon (TOC and DOC), and six agriculturally applied
herbicides, including atrazine and its two major metabolites. Chlorophyll-a analysis was
conducted using fluorometric methods, nitrogen and phosphorus concentrations were determined
with inline digest flow injection analysis, TOC and DOC were measured with a Shimadzu TOC
analyzer, and herbicide concentrations were determined using Gas Chromatography/Mass
Spectrometry (see Appendix C for analytical and measurement methods). All water quality
analyses were conducted in CPCB‟s chemistry laboratories except the herbicides analyses, which
were performed at the University of Kansas‟s Chemistry Department laboratories.
Figure 2. Illustration of wetland survey layout. X = wetland centroid where GPS location was
recorded. A = long axis transect line. B = cross axis transect lines. C = composite water
sample. ● = in situ water quality measurement locations.
Macroinvertebrates
Macroinvertebrate sampling was conducted at four sites in the littoral zone of the major
vegetated habitat areas within each wetland. These zones were usually transitional areas
between open water and emergent macrophyte beds, more commonly referred to as „edge‟
habitat. At each zone, a kick and sweep method with a 500-micron D-frame aquatic net was
used to capture invertebrates in the benthos substrate. The surface of the benthos was disturbed
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