Impact of Different Types of Land Use on Pattern of Herbaceous Plant Community in the Nigerian Northern Guinea Savanna

摘要

This study was carried out with the aim of finding the pattern of distribution and composition of herbaceous plant with respect to different types of land use in the Nigerian Northern Guinea Savannah. Data on plant species was collected using quadrat. Soil sample was collected using core and analyzed for physicochemical properties. The soil physicochemical properties include Total Nitrogen (%), Available Phosphorus (mg/ kg-1), Exchangeable Potassium (cmol (+)/ kg-1), PH, Organic Carbon (%) and Soil textural class. Different effects of land use, which include trampling, arable cultivation, grazing and mowing affected the floristic structure of plant community and soil physicochemical properties in different ways. Each land use type creates a uniquely different type of plant community. Greater impact on the plant community structure was by trampling and cultivation and lesser grazing and mowing. Species dominance based on the Important Value Index (IVI) was found to be the most important indicator of these land use types, and evenness was the least among these parameters that can be used as an indicator of these land use type. Different land use types create closely related some of the soil physicochemical properties, and yet are dominated by different plant species even in contiguous plots, suggesting that the impact of these land use types in shaping plant community structure lays more in their direct impact on the plants rather than indirectly by modifying their local environment. In comparison with Protected Land, grazing and mowing showed relatively no negative impact on the mean soil physicochemical parameters. However, the values of all the soil properties analyzed were largely negatively affected while comparing the Protected Land with the Cultivated and Trampled Lands. Grazing and mowing reduced Species Richness, but greater reduction was by trampling and cultivation. Species diversity was narrowly increased and decreased by grazing and mowing respectively, but largely decreased by trampling and cultivation. Species Evenness was relatively unaffected by trampling, arable cultivation and mowing, but increased by grazing. Such study in a unique geographical region will contribute for cross-biome comparison with similar studies, which is necessary toward generalizations of ecological knowledge for universally unified theories. Knowledge of the pattern of impact of different types of land management as environmental filters of plant species and determinant of plant community structure may be used for prediction, which is very essential for conservation and restoration programmes.