Water quality, habitat, and fish assemblage relationships in middle-order agriculture and forest streams of the Mississippi Alluvial Plain

Ecological Processes

Table 1 Repeated-measures ANOVA of environmental (mean ± SD) variables in agriculture and forest streams of the Mississippi Alluvial Plain

Variable	Agriculture	Forest	Season	Main effect (stream type)	Interaction (season × stream type)
Temperature (°C)	23.32 ± 5.75	21.80 ± 4.60	< 0.001	0.209		0.228
DO (mg/L)	7.00 ± 2.46	6.80 ± 1.14	0.323	0.901		0.111
Specific conductance (µS/cm)	311.79 ± 197.46	231.15 ± 63.22	< 0.001	0.160		0.002
					Summer	0.012
					Fall	0.024
pH (su)	7.96 ± 0.87	7.98 ± 0.41	< 0.001	0.826		0.007
					Spring	0.021
Turbidity (NTU)	219.08 ± 305.75	49.38 ± 16.10	0.043	0.060		0.045
					Spring	0.002
Total suspended solids (mg/L)	48.93 ± 44.26	27.35 ± 11.55	0.057	0.117		0.047
					Spring	0.004
Chloride (mg/L)	21.03 ± 17.83	13.21 ± 8.92	0.005	0.304		0.434
Alkalinity (mg/ L as CaCO₃)	93.03 ± 62.54	98.60 ± 26.80	< 0.001	0.750		< 0.001
					Spring	0.028
Hardness (mg/L as CaCO₃₎	122.53 ± 77.34	105.53 ± 27.72	< 0.001	0.562		< 0.001
					Summer	0.038
TAN (mg/L)	0.18 ± 0.22	0.03 ± 0.03	0.018	0.005		0.002
					Summer	< 0.001
Nitrate (mg/L)	1.09 ± 0.56	0.54 ± 0.14	0.269	0.010		0.102
Total nitrogen (mg/L)	2.52 ± 0.82	2.22 ± 0.40	0.018	0.001		0.212
Phosphate (mg/L)	0.16 ± 0.08	0.05 ± 0.03	0.290	< 0.001		0.638
Total phosphorus (mg/L)	0.47 ± 0.20	0.21 ± 0.13	0.003	< 0.001		0.678
Water-column Chl-a (μg /L)	25.29 ± 18.01	11.83 ± 4.74	0.030	0.087		0.193
Benthic Chl-a (μg/cm³)	0.42 ± 0.27	0.32 ± 0.22	0.002	0.329		0.988
Total Habitat Score	150 ± 26	182 ± 10	0.022	0.020		0.372
Instream Habitat Score	70 ± 9	83 ± 9	0.039	0.010		0.829
Riparian Habitat Score	80 ± 18	98 ± 2	0.056	0.040		0.055

Data were collected in spring, summer, and fall 2014. Significant effects (P ≤ 0.05) that were interpretable are denoted with bold print. Results for salinity were deemed uninterpretable and are not shown