Aquatic macrophytes diversity and distribution: a case study of Ifewara Reservoir, Osun State, Nigeria

Abstract

This study determined the species composition, diversity, distribution, spatio-temporal variations and community structure of macrophytes community in Ifewara reservoir, Osun State, Nigeria. Samples were collected from ten stations established over the three main basins of the reservoir (upper-flow, middle and lower basins). At each sampling station, plant species were collected and identified following standard procedures at the IFE Herbarium. The generated data were subjected to Clustal analysis, Principal Component Analysis (PCA) and Analysis of Variance (ANOVA). A total of 22 macrophytes species which belong to 17 genera and 13 families were recorded. The most dominant family was Onagraceae, which comprised four species. About two-thirds (65.2%) of the macrophtyes were of emergent form, with 30.4% as floating form, and 4.3% as submerged form. Azolla pinnata, Wolfia microscopica and Lemna minor were recorded only during the dry season with a record of about 22 species. PCA and Cluster analysis revealed a high correlation between upper and lower basins. The highest mean occurrence of 45.3±6.4% was recorded in the upper basin of the reservoir. The study concluded that the macrophytes community of the Ifewara reservoir was fairly diverse and most species were widely distributed.