COMPOSITION AND STRUCTURE OF HERBACEOUS FLORA AND VEGETATION OF THE LOWER DELTA OF OUÉMÉ IN SOUTHERN BENIN

Abstract

The composition of the herbaceous vegetation of the Lower delta of Ouémé was assessed using phytoecological data records performed following the method of Braun-Blanquet from a systematic sampling transect. The observations were made in 10 m x 10 m plots. Herbaceous flora consisted of 257 species distributed in 179 genera and 60 families which most represented species were Leguminosae, Cyperaceae, Asteraceae and onvolvulaceae. The most frequent species were: omoea aquatica (39%), Echinochloa pyramidalis (34%), Leersia hexandra (27%), Justicia anselliana (25%) and Alternanthera sessilis (22%). The number of species was around 7 in aquatic vegetation and 174 in fields and fallows. The diversity index was 0.33 to 3.42 bits with a Pielou equitability from 0.28 to 0.96. Species with wide biogeographical distribution types were dominant (53% of the area).