Assessment of Grass Composition and Distribution Pattern on Pipeline Right-of-Way in Bayelsa State and its Potential Use for Dominant Grazers

This study investigates grass diversity and distribution pattern along a pipeline linear corridor in two Local Government Areas in Bayelsa State and the feasibility of utilizing them for cattle grazing. The areas lie within coordinates 4º15'N and 5º23'N, and 5º22'E and 6º45'E. The term grass is applied in this paper to describe a variety of vegetation forms, exclusively composed of herbaceous plants. Random pair sampling design was used, and species richness and evenness were determined using the taxonomic data obtained. The results revealed nineteen families and were represented in four different growth habits. The most often encountered families were Poaceae, Cyperacaee, and Asteraceae. Sixty-seven (67) species were sampled in the Ogbia pipeline corridor, and 66 species in Yenagoa. Sixty-six of the species had 99% occurrence on both sites. Poaceae and Cyperaceae account for two-thirds of the entire species recorded, and were the prevalent by growth habits. Herbs ranked second, the majority of which were Asteraceae; other growth habits observed were vines, and ferns. Vines were rare in occurrence, whereas ferns clumped in their distribution pattern. Simpson index values of 0.023 and 0.026 and Shannon-Weaver index values of 3.953 and 3.346 were recorded in Ogbia and Yenagoa sites, respectively. The evenness index values (0.003 and 0.003) and Margalef values (7.449 and 7.329) were also obtained from the two sites, respectively. The highest species density in Ogbia was observed for P. laxum (7.93m2), while L. haxandra yielded the highest mean density of 9.42m2 in Yenagoa. A. compressus, O. longistamiinata, and A. gangetica recorded the highest frequency index (70%) in Ogbia, whereas, A. compressus constituted the highest frequency index (75%) in Yenagoa, followed by O. corymbosa and P. maximum (70%) each. The ability of these species to thrive in pipeline corridor conditions underscores the potential use of the corridor as alternative grazing lands.