SOCIO-ECOLOGICAL IMPACTS OF WATER HYACINTH (Eichhornia crassipes) INVASIONS ON AKANYARU WETLAND, RWANDA

Abstract

Water hyacinth has been reported to invade African freshwater bodies massively during 1950’s due to eutrophication. In Rwanda the weed has been reported to invade Akanyaru river in 1987. Presently, it has been found almost all over the country, which resulted in a chronic environmental, social and economic problem in the country. Therefore, the aim of this study was to explore the socio-ecological impacts of Water Hyacinth (Eichhornia crassipes) infestation on Akanyaru wetland in Rwanda. The data was obtained through stratified sampling method where the sampled area was stratified into three strata according to the level of Water Hyacinth invasion (High invasion (Musenyi); Medium invasion (Ntarama) and No invasion (Nyarugenge). Moreover, household survey was conducted to explore the socio-economic impact of the species. The results have shown that Water hyacinth affect water quality of Akanyaru river as the highest TDS, Turbidity, Temperature, EC and BOD were recorded at highly invaded area and the highest DO, Sulphates, phosphates and nitrates recorded at the control. About 16.33% of the respondents have responded that they use a lot of time for fishing, 13.78 % responded that Breaking fishnet is the problem, 2.55 % responded that they do face a problem of disappearance of some fish species, 30.10 % responded hindering fish catchability and 32.65% the increase in fish price. About 31.12% of the respondents have responded that water hyacinth affect transport by causing the increase in time to reach the destination, while 28.06 % said that it reduced income inquired from transport industry; 12.24% of the respondents responded that it causes flooding in their farms, while 33.67 % responded that it causes water level reduction which affect water needed for irrigation purposes. The weed does also affect the macrophyte community composition and diversity negatively as during the study a huge number of macrophyte species were recorded at the area with no invasion, and in some cases the weed has been noticed that it changed the community to a monotypic one. Understanding the impacts of the species will help to improve management programs and policies to address its socio-economic and ecological menace.