WATER HYACINTH INVASION IN THE RIFT VALLEY LAKES BASIN—AN EMERGING ENVIRONMENTAL AND SOCIO-ECONOMIC CHALLENGES: A REVIEW PAPER

Water hyacinth (Eichhornia crassipes) occurs almost throughout wetlands of Africa and poses serious socio economic and environmental problems of people in riparian communities, which added constraints on the sluggish development process. This review aims to show the spatial distribution, characteristic and impacts of water hyacinth to initiate urgent policy attention and amelioration mechanisms in Rift Valley Lakes Basin (RVLB). This invasive weed has spread quickly from Amazon to many tropical and sub-tropical countries and known to cause major ecological, environmental, and socioeconomic challenges. In Ethiopia, water hyacinth was officially reported from Awash basin, Koka Lake in 1962. Then, the plant had succeeded in infesting wetlands in western and north western Ethiopia, and recently lakes of RVLB mainly Lake Ziway and Lake Abaya. Lake Ziway– the shallow freshwater ecosystem reputed for its prolific birdlife, rich fish fauna and home to hippos population, islands of ancient monasteries and engine (irrigation water source) of mechanized to smallholder farms, is a corridor of employment, industrialization, and socioeconomic development. On top of these all development led pressures, invasion of water hyacinth has conveyed competition in water demand and enhanced immense ecological and environmental challenges. Lake Abaya the second largest lake next to Lake Tana, has recently been overrun by water hyacinth mainly sourced from the eastern side of the lake. Researchers reported that water hyacinth in Lake Abaya affects the macrophyte community composition, abundance and diversity negatively. This affirms its wider impact on Ethiopian aquatic ecosystems. A comprehensive look at the short and long term consequences of its expanding invasion within the framework of specific local environmental, ecological and societal conditions is long-overdue. Proper policy attention and interventions would reduce invasion of water hyacinth and limit water depletion to enhance water resource potential. It also reduces eutrophication, improves water ecosystem health and the livelihood of the local community and other water users. Keywords: Abaya Lake, Ethiopia, invasive species, Rift Valley Lakes Basin, Water hyacinth, Ziway Lake