Ecological assessment of Cheffa Wetland in the Borkena Valley, northeast Ethiopia: Macroinvertebrate and bird communities

摘要

A comparative study of macroinvertebrates and bird communities was undertaken to assess the ecological integrity and human impact in Cheffa Wetland, northeastern Ethiopia. The study was undertaken from February to May 2010. Physicochemical parameters of the water, birds, macroinvertebrates and human impact classes were assessed at 10 sites in the wetland exposed to different anthropogenic activities. We have compared Shannon index of diversity of macroinvertebrates and birds along with different habitat classes. Multivariate statistics were used to extract the main driving forces for changes in macroinvertebrate and bird community patterns out of a complex data set. Subsequently, we compared the diversity indices of the macroinvertebrate and bird communities for the detection of human impacts. A total of 2789 macroinvertebrates belonging to 34 families in 10 orders were collected and 3128 birds belonging to 57 species recorded. Macroinvertebrates belonged to five different orders: Hemiptera (seven families), Coleoptera (five families), Odonata (five families), Gastropoda (seven families) and Diptera (five families), exceeding 77% of the overall sample. Abundance and diversity of the bird and macroinvertebrate communities were related mainly to concentrations of DO, nitrate and chloride, habitat conditions, and human disturbances. Of the 57 species of birds recorded, the cattle egret (Bubulcus ibis), white-faced whistling ducks (Dendrocygna viduata), Egyptian goose (Alopochen aegyptiacus) and spur-winged lapwing (Vanel-lus superciliosus) were the most abundant. The physicochemical variables showed great variation among sites. The results revealed that human interference in wetland may result in serious ecological imbalances in the natural life cycle and impact on human welfare. Long-term studies are required to predict changes in wetland ecology and population dynamics, with the objective of developing appropriate measures by federal, regional and local stakeholders to ensure wetland restoration and sustainability.