Socio-ecological Impacts of Water Hyacinth (Eichhornia Crassipes) Under Dry Climatic Conditions: The Case of Shagashe River in Masvingo, Zimbabwe

In Zimbabwe, aquatic environments continue to endure water hyacinth (Eichhornia Crassipes) invasions. The intricate and distinctive characteristics of water hyacinth make it one of the most ecologically resilient aquatic plants enabling it to invade major water systems. There is still paucity of scientific knowledge about the social and ecological ramifications of this macrophyte. In this study, we assessed the social and ecological effects of water hyacinth along Shagashe River. The mixed methods research design was adopted as the strategy of inquiry. Sampling sites were selected to compare two environments along the river, one under the cover of water hyacinth and the other without water hyacinth. Moreover, the sampling was done in two distinct periods i.e. the dry season and wet season. In each of these sections and periods, 15 sampling points were selected using the stratified random sampling criteria. Ecological data for the two sections were compared by means of one way analysis of variance (ANOVA). A comparison was also done on the social data from the two sections of the river and also from the two seasons. Ecological data was collected mainly through field measurements of biodiversity, sedimentation rate and velocity. Laboratory testing of evaporation rate and water parameters augmented the ecological data collection processes. Data on sociological aspects was collected mainly through interviews, questionnaire surveys and the story telling approach. Results show that the water hyacinth infested environment had low phytoplankton productivity, low dissolved oxygen, high sedimentation rates, high water loss and reduced river velocity among other ecological effects. Communities have been affected through lack of access to debris free water, reduced access to water points, reduction of fish catch and clogging of irrigation pipes. We conclude that water hyacinth has significant socioecological ramifications along Shagashe River. There is need to identify and exploit potential opportunities provided by the presence of water hyacinth such as biogas production, use as animal feed and use as raw material for the craft industry in order to convert the water hyacinth socio-ecological “curse” into a “blessing”.

Author(s): Chapungu L, Mudyazhezha OC and Mudzengi B