Socio-ecological impacts of water hyacinth, Eichhornia crassipes (MART.) in Lake Tana, Gulf of Gorgora, Ethiopia

Abstract

Water hyacinth is one of the aggressive alien aquatic macrophyte threatening biodiversity, economic development and human wellbeing. Currently, the macrophyte has invaded Lake Tana and its catchment causing several socio-ecological impacts. So far, there is limited information on socio-ecological impact of water hyacinth in Lake Tana specifically gulf of Gorgora. Therefore, the main aim of this study was to assess socio-ecological impact of water hyacinth in Lake Tana gulf of Gorgora, located in North West of Ethiopia from November 2019 to January 2020. Two sampling sites (infested and non-infested) were identified based on infestation of water hyacinth. A total of 30 water and 12 water hyacinth samples were collected with a survey of 50 individuals. Results revealed that water quality, phytoplankton diversity, fishing, navigation, health condition of local people, recreational and aesthetic value were impacted negatively due to infestation. Conversely, higher accumulation of toxic heavy metals and dissolved metallic ions in the root, stem and leaf of the macrophyte impacted positively. Infestation of the macrophyte significantly affected water quality and species diversity of Lake Tana. In the infested site; DO (3.3 to 4.5), SRP (0.012 to 0.023 mg L-1), TP (0.24 to 0.28 mg L- 1), NO3-N (0.74 to 0.97 mg L-1) and TN (2.1 to 3.2 mg L-1) were significantly (p < 0.01) lower than non-infested site. Generally, infestation of water hyacinth negatively impacted the society and the ecology in Lake Tana catchment. Therefore, continuous monitoring and management of the macrophyte is required.