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Sustainably managed watershed ecosystems play vital roles in ecological stability and contribute to livelihood sustenance. Unfortunately, most watershed ecosystems are threatened by anthropogenic activities such as arable crop cultivation, and infrastructural development. This study investigated the influence of land use on soil physicochemical properties and floristic composition in the watershed of a man-made reservoir (Awba dam). A systematic random sampling technique was used to lay plots (25m by 25m) in alternate positions on identified land use types. Plant species were enumerated and composite soil samples (0-25 cm depth) were collected from four quadrants in each sample plot. Descriptive statistics and diversity indices were computed, and principal component analysis were used to assess the relationship among the variables. Land-use significantly influenced soil chemical properties. Soil from the secondary regrowth had the highest pH (6.25), grassland had the highest organic carbon content (1.95%) while wetland had the highest available phosphorus (40.90 %). There was a significant relationship between species diversity and soil physicochemical properties. A positive relationship was observed between the species dominance, evenness indices with sodium Fe, potassium and calcium. The analysis also revealed that manganese, acidity, and sodium content in soil were more associated with farmland, availability of phosphorus in soil soil PH and high species diversity are more associated with riparian forest, while number of species occurrence are associated with secondary regrowth in the area. This study had revealed that land use system influenced tree species diversity and soil properties in the watershed ecosystem. Therefore, appropriate measures are needed to ensure the survival of key tree species in the watershed to help maximize the structural and functional role of the ecosystem. |
