Effects of aquatic macrophytes on the limnology and utilization of Moro reservoir, Ilorin, Nigeria

Abstract

Qualitative sampling of the macrophytes, invertebrates fauna attached to the macrophytes and physico-chemical parameters of Moro reservoir was undertaken to study the effects of the macrophytes on the limnology and utilization of the reservoir and its resources. Eight species of macrophytes were recorded with Eichhomia crassipes mart; Pistia stratiotes linn; and Heterantheria callifolia solms; being the dominant species. Bulinus and Biomphalaria species of snails, adult insects, larva and nymph of oligochaetes worms were the invertebrate fauna found attached to the macrophytes. The high concentration of nutrients such as nitrate, calcium and magnesium promoted the growth of the macrophytes which in tum
brought changes in the limnological conditions of the reservoir as well as having consequences on public health as a result of the vectors of water borne disease found attached to them. Interferences with fisheries, domestic water supply, irrigation, navigation and recreational use of the reservoir was also observed due to the massive growth of these macrophytes on the reservoir. Appropriate management measures to control the weed in the reservoir such as the introduction of biological agents, mechanical and chemical controls and limnological manipulations were suggested.

Key words: Macrophytes, invertebrate fauna, limnology, management and reservoir.