DefinePK

Abstract

This study investigates the biodiversity, diversity, and distribution of Rotifera in the upper sector of the Tigris River, Wasit Province, Iraq, from January to December 2022. Five sites, approximately 10 Km apart, were selected along a 1415 Km stretch of the river. A total of 67 rotifer taxa were identified. The highest density recorded was 27,454 individuals/m³ in November, and the lowest was 710.6 individuals/m³ in July. The relative abundance index identified five less abundant rotifer species. The species richness index ranged from moderate to ideal, while the Shannon-Wiener index indicated moderate diversity. The species uniformity index varied from unbalanced up to highly balanced. Sites 2 and 3 had the highest similarity index values, whereas sites 1 and 4 had the lowest. Thirty-four taxa were constant species, with others being accidental or accessory. Our results concluded that upstream areas recorded lower relative abundance compared to downstream. According to the Shannon-Wiener index, the Tigris River can be classified as having high diversity, suggesting a good and diversified aquatic ecosystem