Incidence of Freshwater Aquatic Macrophytes in Relation to the Nutrients Content of Gwaigwaye and Mairuwa Reservoirs, Funtua, Nigeria

Abstract

Studies were conducted between (September 2017 to October 2018) to investigate the variation in the compositional distribution of macrophyte communities in relation to the nutrient contents in the water and sediments of Mairuwa and Gwaigwaye reservoirs, Funtua, located in the Northern vegetation of Nigeria. All the nutrients from sediments were analyzed using standard procedures with spectrophotometer, flame photometer, and titration methods. Nitrogen, phosphorus, and calcium were higher in Mairuwa reservoir than in Gwaigwaye, while potassium, on the other hand, was higher in Gwaigwaye than in Mairuwa reservoir. Magnesium was not detected in either of the two reservoirs. The modified method of flora collection was used with a random sampling technique. The correlation analysis indicated that the distribution and abundance of aquatic macrophyte composition were significantly (P<0.05) different. The overall community structure was made up of nine (9) species from Mairuwa and eleven (11) species from Gwaigwaye reservoirs. Both the number of species present and the densities of such species were higher in Mairuwa than in Gwaigwaye reservoir. Four growth patterns of macrophytes were observed viz; emergent macrophytes were the dominant (56.7%), floating macrophytes (26.5%), submerged macrophytes (13.4%), and the least marginal macrophytes (3.4%). Similarly, species densities (stands per square metre) ranged from 1-29m in Mairuwa and 4-90m in Gwaigwaye. Implications of these trends to the well-being of the two ecosystems are highlighted. Government and non-governmental organizations at all levels should ensure that the precious aquatic resources are solely protected by enacting laws against the anthropogenic action of the inhabitants in and around the catchment.