During our recent movie making campaign in the Lake Tana Biosphere Reserve we could witness one of the current major threats to the lake: the water hyacinth invasion.
Recently added to the list of UNESCO Biosphere Reserves, Ethiopia’s Lake Tana is a multi-purpose lake, facing different challenges, among them a water hyacinth invasion is a serious thread. According to the Water Hyacinth Coverage Survey Report, produced by scientists from Bahir Dar University in May 2015, „it was officially recognized that one of the top ten ecologically dangerous and worst invasive weeds, water hyacinth (Eichhornia crassipes), infested Lake Tana.
According to a 2012 survey, about 20 ha of the shore on the north-eastern part of Lake Tana was infested. Following this infestation, the Bureau of Environmental Protection, Land Administration and Use (BoEPLAU) made a physical removal campaign. It is estimated that between 90–95 % of the water hyacinth was basically removed from the lake through this manual removal approach in 2013.
In August 2014, a survey report by experts revealed water hyacinth re-outbreak in Lake Tana. More than 50.000 ha of the shore area and about 128 km shore length was infested.
As suggested by Ogutu-Ohwayo, the plant might have been introduced “unintentionally” by botanists in the 1980’s. The plant is causing a great threat to the general ecosystem of the lake and human activities as well, mainly by reducing water quality. The “invasion” phenomenon is even more exacerbated by massive eutrophication resulting from nutrients emanating from intensive agriculture surrounding the lake. The negative impacts of water-hyacinth have pushed the scientific community to call for an urgent mobilization of expertise. Facing the limits of biological, mechanic and chemical control, a critical need for paradigmatic change is required, in order to minimize the spread of the species.
UNESCO in partnership with the African Union Commission, HOAREC and ISHU produced a feasibility-study in order to provide a comprehensive picture of the waterhyacinth’s biology and associated challenges on Lake Tana while contributing to the paradigmatic shift of considering the plant as an opportunity rather than a threat. This feasibility study tests the potential harvest of water hyacinth towards the production of bio-fuel and organic agro-fertilizer, which will be highly valuable for biodiversity conservation as well as towards the green economy.
Meanwhile the water hyacinth threat is omnipresent and is gaining a lot of attention in social media, among environmental activists, the civil society, singers, poets, etc. E.g. the team of the Blue Nile Resort Hotel organized a physical removal campaign. Although this is a serious threat, the problem holds the potential to lead towards growing environmental awareness at Lake Tana and within its community in general.