Physico-chemical and Macroinvertebrate Assessment of Guji, BiloIlala and Kumbabe Wetlands in Didessa head waters, southwest Ethiopia.

Abstract

Manyecological studies indicate wetlands are susceptiblefor different ecological challenges. The present study aimed to assess the physicochemical and biological water quality of BiloIlala, Guji and Kumbabewetlands in Didessa headwaters in southwest Ethiopia. In this study the pH, electrical conductivity, water temperature and DO were measured insitu using a multi- meter with different sensor probes while water samples were analyzed for BOD5, TSS and nutrient (nitrate, ammonia and orthophosphate) in the laboratory following standard procedures. Significant variations in the mean values of physico-chemical parameters and nutrients among the three wetland groups were tested using Kruskal-Wallis followed by Mann-Whitney pair wise post-hoc tests due to lack of homoscedasticity and normality in the data. Normality and homoscedasticity of the data were tested using Shapiro-Wilk and Leven statistics respectively. Benferroni p values corrected for multiple testing were used to evaluate significance of pair wise comparisons for the Mann-Whitney post-hoc tests. Spearman’s correlation coefficient was used to test the possible correlations among the measured parameters. Macroinvertebrates samples were collected using kick net and preserved in 75% alcohol and identified in laboratory following standard keys. Statistical analyses were run in PAST version 3.08 and SPSS version 16.Acordingly average water temperature of the wetlands varied from 21.4°C to23.5 °C, average dissolved oxygen varied from 6.02 mg/l to 6.79 mg/L, average EC varied from 62 µS/cm to 119.85 µS/cm, pH values varied from 6.99 to 7.31, TSS values for the wetland varied from 0.004 mg/L to 0.007 mg/L. Whereas the median values of NH3, NO 3 -and PO 4 3-varied from 0.06 mg/L to 0.14 mg/L, 0.67 mg/L to 3.09 mg/L and 0.45 mg/L 0.81 respectively. Similarly MMI scores for all the wetlands showed very good wetland condition. Habitat assessment also implies that grazing has the highe