ADAPTATION OF FIELD-BASED ECOLOGICAL HEALTH ASSESSMENT PROTOCOL FOR CENTRAL AND SOUTH EASTERN HIGHLAND RIVERS IN ETHIOPIA

Abstract

Rapid bioassessment protocols have been developed as inexpensive monitoring tools to assess the health of streams, rivers and lakes. The present study was conducted to adapt macroinvertebrate-based field protocol for assessing the ecological health of streams and rivers in the central and south-eastern highlands of Ethiopia. Abiotic and biotic data were collected from 154 sites distributed in the upper section of four major basins, namely Awash and Rift-Valleyin the centeral highlands, and Wabi-Shebele and Genale. The field-based assessment protocol was adapted based on the rapid field protocol developed for assessing highland streams in the Hindu-Kush-Himalayan regions in 2010. The decision support table of the protocol includes both abiotic and biota components that can be identified in the field, with a special focus on benthic macro-invertebrates as bioindicator. The sensitivity of a specific benthic invertebrate (BMI) taxon to different level of degradation was based on biotic score (ETHbios) developed for assessing Ethiopian highland streams and rivers in 2015. To ensure simplicity of the protocol, only 15 BMI taxa with clear ecological quality preference are included. The sensitivity ranges from less tolerant taxa such as Perlidae, Scirtidae and Lepidostomatidae to tolerant taxa such as Psychodidae, Chironomidae and Syrphidae.  The protocol is manually calculated in the field and used to categorize streams and rivers into five ecological water quality classes namely high (I), good (II), moderate (III), poor (IV) and bad (V). This categorization serves as an ‘early warning’ method to identify areas that require urgent attention for intervention measures or detailed investigation in the future studies. The method can be considered as rapid, inexpensive but scientifically sound monitoring method to evaluate the ecological conditions of running waters in the highlands of Ethiopia.

Key Words: River health, Highland streams, Field protocol, Benthic invertebrates

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