Diversity assessment of benthic macroinvertebrate communities in <scp>B</scp>anco <scp>N</scp>ational <scp>P</scp>ark (<scp>B</scp>anco <scp>S</scp>tream, <scp>C</scp>ôte d'Ivoire)

Abstract

Abstract In the present study, a first inventory of benthic macroinvertebrates in the B anco S tream, C ôte d'Ivoire, and the correlations between environmental variables and taxonomic richness were analysed. Seven stations were sampled monthly over a 1‐year period, using a hand net (10 × 10 cm, 250 μm mesh, 50 cm length). One hundred and thirty‐two macroinvertebrate taxa were recorded. These taxa were distributed among 74 families and 15 orders belonging to I nsecta (118 taxa; 89% of total richness), O ligochaeta (seven taxa), C rustacea (five taxa) and M ollusca (two taxa). K ruskal– W allis test revealed significant difference (at least P &lt; 0.05) in macroinvertebrate richness between upstream stations ( S 1 and S 2) and stations S 4, S 5 and S 6. Chironominae and T anypodinae (Insecta) were the two very frequent taxa in all the stations. Lumbriculidae ( O ligochaeta), D esmocaris trispinosa ( C rustacea) and E urymetra sp. ( I nsecta) were frequently found in the samples. Hierarchical cluster analysis revealed three groups of sampling stations according to taxonomic similarity. Taxonomic richness was significantly and negatively correlated with conductivity, while it was significantly and positively correlated with substrate types (woody debris and gravel). Due to the fact that B anco stream is the locality type of an endemic shrimp species ( M acrobrachium thysi ), this basin is of high conservation priority.