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Abstract

Abundance and diversity of zooplankton and macro invertebrate communities in Fogera floodplain was studied. Three sites were selected in study area based on land use and substrate type. Physico-chemical data ware taken in situ using combined probe, temperature, pH, TDS, conductivity and secchi depth for water transparency. Zooplankton and Macro invertebrate samples were collected by using a 250 m mesh sized deep net. Data ware sorted and identified at family level in laboratory. Result of two way ANOVA indicated that all physico-chemical parameters showed significant spatial and temporal variation. Total of 26 taxa comprising of 4,344 individuals of macro invertebrates were collected from study sites. Taxa richness at study sites ranged from 21 at Amendamesk to 24 at Taqua and Alewbahir. Invertebrate species richness was dominated by collectors and predators at all sites. Collectors were relatively higher at (AB), while predators were higher in abundance and diversity in all sites. Some of the macro invertebrate metrics calculated from sample data showed spatial and temporal variation. Metrics Shannon Diversity Index, evenness index and per cent taxa richness were lower during dry season while Dominant Taxa were higher. Sensitive metrics and Taxa Richness showed negative correlation with temperature , pH, TDS, Conductivity and positive correlation with secchi depth while Dominate taxa responded in the opposite way. Zooplankton community in study sites was dominated by copepods in all sites which contributed 88% of total community and were best represented by calanoids while Cladocerans and rotifers were least abundant groups. In general floodplain was dominated by rice farming and has favorable environment for aquatic fauna including fish although, the area was threatened by anthropogenic impacts. Therefore, wise use of resources should be adapted to maximize effective utilization of these resources by developing environmentally meaning full strategic plans and implement a catchment-based floodplain management and conservation activities to address upcoming problems.