Dry Season Identification And Species Characteristics Of Aquatic Macrophytes In The Floodplains Of River Benue At Makurdi

A survey experiment was conducted during the dry season (March- April) of 2013 in the floodplains of River Benue in streams, ponds, main drainage channels and marshy areas within Makurdi metropolis comprising nine (9) locations, to determine the prominent dry season aquatic macrophytes infesting these water areas, their distribution and species characteristics. Macrophyte survey was carried out based on a combination of transects. In each transect all species and ecological groups (emergent and floating-leaved plants) were recorded. A total of 31 aquatic macrophytes were identified. Of all the macrophyte species identified, those belonging to the families Cyperaceae Onagraceae, Poaceae and Pontederiaceae respectively were the dominant group found and most distributed in the sample locations. However, Water hyacinth (Eicchornia crassipes), was observed to be the single most distributed macrophyte specie. The percentage weed occurrence in River Benue was observed to be significantly higher (p<0.05) than in all the other locations. This was followed by Berbesa and Tyumugh, Agongul, University of Agriculture Annex, Katsina-ala Street, BBL, Adubu, New Bridge Abattoir and Industrial Layout. Also, in River Benue, Eicchornia crassipes, Azolla pinnata, Cyperus difformis, Cyperus erecta, Kyllinga pumila, Pycreus lanceolatus and Cyperus haspan showed the highest macrophtye abundance. At Adubu and New Bridge Abattoir Eicchornia crassipes was observed to have maximum Macrophyte abundance (MA) 5, Frequency of occurrence (FO) 100%, Relative abundance (RF) 26.6% and Dominace index (DI) 100%, respectively. At Makurdi Industrial Layout, even though Eicchornia crassipes recorded a comparatively less MA (4), the FO (100%) and DI (100%) was observed to be the same as in Adubu and New Bridge Abattoir while the RF was 57.1%. The Simpson’s divertsity index (SDI) results indicated the following order: River Benue 0.92% > Berbusa 0.86% > Tyumugh 0.84% > University Agriculture Annex, Katsina-ala street 0.81% > Adubu 0.79% > Benue Bottling Company (BBL) 0.77%.