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Invasion of Water Hyacinth (Eichhornia crassipes) Is Associated with Decline in Macrophyte Biodiversity in an Ethiopian Rift-Valley Lake—Abaya

Macrophytes, as an integral component of wetlands and shallow lakes, play critical ecological role, such as nutrient cycling, and nitrogen removal through denitrification coupled with nitrification. Water hyacinth (Eichhornia crassipes) is a menace to global aquatic environments with serious and devastating consequences. It is also an invasive plant species introduced to Ethiopian water bodies around the mid-20th century with recently exacerbated devastating ecological and economic consequences.

In this paper, the authors reported the impact of the invasive plant species on macrophyte species assemblage and biodiversity in Lake Abaya, southwestern Ethiopia. In the study, the authors compared four sites in Lake Abaya, two hyacinth infested and two non-infested, each site consisting of 15 plots. And each plot (quadrats) with a size of 0.5 × 0.5 m2 and 25 meter apart from each other. In the field, macrophytes were counted within each plot. Besides, macrophyte species richness, abundance and Simpson’s diversity index, and similarity index for plots was calculated using SPSS version and 17 Multiple Correspondence Analyses with two Dimensions was computed.

The results showed that water hyacinth affected the macrophyte community composition, abundance and diversity negatively. Even though some macrophyte species from the Poaceae and Cyperaceae families appeared to coexist with the alien plant, the invasive species had reduced macrophyte abundance and diversity at the infested sites, and in some cases changed the community to nearly monotypic flora. The data affirmed that water hyacinth had the potential to alter macrophyte composition, abundance and diversity in the wider Ethiopian aquatic ecosystems.

In conclusion, the paper reveals that wetland ecosystems, especially shallow freshwater lakes in the tropics, continue to face sustained human infraction because of their close ties with local economies and the livelihood of communities. And a comprehensive look at the wider environmental, economic and other impacts of the invasive water hyacinth in Ethiopia is currently not only warranted but overdue.

Article by Bedilu Bekele Mengistu, et al, from Ethiopia and USA.

Full access: http://mrw.so/1Q6SnC
Image by G-TAKI, from Flickr-cc.

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