IMPACT OF ECOHYDROLOGICAL INTERVENTIONS ON MACROINVERTEBRATE DIVERSITY ASSOCIATED WITH PHYSICOCHEMICAL PARAMETERS ON THE WETLANDS ALONG THE SOUTHEASTERN SHORE OF LAKE TANA, ETHIOPIA

Abstract

Biological indicators have the improvement of monitoring ecological conditions and to measure of anthropogenic impacts on aquatic ecosystems. This indicates that appropriate wetland management mitigation measures that should be implemented in degraded wetlands to conserve biodiversity and improve water quality. The aim of the study was to investigate the impacts of ecohydrological intervention in relation to macroinvertebrate diversity and relate macroinvertebrate diversity with physicochemical parameters of the wetland in Lake Tana shore intervention site. Sampling stations were selected according to vegetation gradient. The sampling procedure employed using quadrats along transects following the main ecological gradient of water depth and vegetation structure and growth form. Four quadrats at every 25m distance were laid at each transect. A total of 24 quadrats of 1m x1m size were taken. Collected samples of each quadrat were pooled to represent each sampling site. One way ANOVA was further done to test any significant variation in macroinvertebrate and physiochemical attributes among stations. The Hilsenhoff Family-level Biotic Index (HFBI) was calculated for macroinvertebrate families. The HFBI index was analyzed and identified 975 macroinvertebrate individuals belonging to 15 families which were collected from all sampling sites during the study period, and the most dominant family were Hydrophilidae Coenagrionidae and Physidae. Based on the Shannon diversity index, the Gumetirs wetland was grouped under good ecological condition as compared to the remaining two reference wetlands. There was a significant variation in abundance and biodiversity of macroinvertebrates among sampling sites and better conditions exist at the intervention site. The correlation analysis between physicochemical parameters and macro-invertebrate abundance showed that organic carbon and temperature are most likely positively correlated with macroinvertebrate abundance. Thus, high macroinvertebrate diversity indicated that wetlands found in a good ecological condition.