Distribution, composition and impact of environmental factors on benthic macroinvertebrates functional feeding groups and ecosystem attributes in river Yaah (East Lekie)

From July 2022 to May 2023, a study was carried out in the Lékié division (Center region) and its objective was to evaluate the composition and distribution of benthic macroinvertebrates functional feeding groups in relation to the characteristics of environmental factors and determine the ecosystem attributes of the Yaah watercourse. For that, in three sampling stations, the collection of water samples for analysis and benthic macroinvertebrates were carried out according to standard methods. The grouping of benthic macroinvertebrates into functional feeding groups was done thanks to the keys and appropriate works. A total of 730 benthic macroinvertebrates belonging to 38 families were identified and the families of Belostomidae (11.51%) and Libellulidae (10.96%) were the most dominant. The 38 families of benthic macroinvertebrates identified were grouped into 5 trophic functional groups, predators (63.29%) and Shredders (22.19%) were largely predominant. The distribution of collectors varied from YA 1 to YA 3. The abundance relative of Shredders decreased from upstream to downstream while that of filters increased earlier and these variations were consistent with the River Continuum Concept. The electrical conductivity was influenced positively the distribution of scrapers and gathering collectors while the suspended solids negatively influenced the distribution of shredders and positively the distribution of predators. The watercourses sampled were heterotrophic, conducive to the development of shredders and dominated by Coarse Particulate Organic Matter and predators.