Author(s): Mathieu Kobenan Kra, Idrissa Adama Camara, Edia Oi Edia, Mexmin Koffi Konan, Dramane Diomande and Allassane Ouattara

Abstract: This paper presents a study on aquatic macroinvertebrate communities in lower Comoe river belonging to Grand Bassam wetland (Côte d’Ivoire). Six sites (C1-C6) were sampled during eight campaigns from June 2014 to May 2017. At each site macroinvertebrates were collected using a Van Veen grab and kick-net (25 x 20 cm, 500 µm mesh size). Environmental variables were recorded also. Water was collected from each sampling site for nutrient (phosphorus, nitrate) analysis in laboratory. A total of 97 macroinvertebrate taxa belonging to 49 families, 15 orders and 08 classes were identified in the lower Comoe river. Insecta was the most representative class (70 taxa) followed by Gastropoda (14 taxa). The order of Coleoptera was the most diversified (20 taxa) followed by Odonata (15 taxa). The Shannon-Weawer index varied between 0.66 and 2.82 and the Pielou evenness index between 0.30 and 0.96. The highest values of the rarefied richness was observed in the C1 (06) and C2 (6.45) sites, which were less subject to the different anthropogenic pressures, whereas the lowest values were recorded in C5 (2.20), a site under pressure from pig farming and organic fertilizers. The Sorensen Similarity index varied from 35.44% to 43.37% and was higher between C1 and C2, which are very close sites. The rare taxa were the most numerous at the different sites. Association of the different indices shown that C1, located upriver is less impacted and C5 in downriver the most impacted site.

Pages: 472-481  |  784 Views  79 Downloads

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