SPECIES CHARACTERIZATION IN RELATION TO EDAPHIC FACTORS IN A MANGROVE SWAMP FOREST: AN ORDINATION APPROACH

Species characterization in relation to edaphic factors was carried out in a mangrove swamp forest using ordination approach (PCA). Vegetation and soil were sampled systematically with a ten 50 x 10 m quadrat. In each quadrat, soil samples were obtained at the depths of 0 – 30 m while plants were identified to species level and their frequency, density, height, basal area and crown cover were determined. The floristic catalogue revealed a total of 10 species belonging to 8 families. Rhizophora mangle had the highest density value (120.41±16.04 st/ha) while Nypa fruticans, Rhizophora mangle and Paspalum vaginatum respectively had the highest frequency value (100%) Rhizophora mangle was the tallest species (11.50±1.37 m) as well as the species with the widest coverage (10.68±1.08 m2/ha). Elaeis guineensis had the largest (1.79±0.05 m2/ha) basal area (0.13±0.04 m2/ha). The use of PCA delineated three principal component axes (VS1, VS2 and VS3). The first, second and third axes were grouped as vegetation adaptation to salinity gradient, niche preference gradient and residual niche preference gradient, respectively. Positive associations showed nutrient levels that enhanced growth while negative relationships showed levels of nutrients that were limiting to plant performance. Conclusively, this study showed that the vegetation and soil factors in this mangrove swamp are highly interrelated, as shown by the magnitudes of correlations between them, hence, highlights that the interactions that govern mangrove abundance may produce different zonation patterns depending on the underlying environmental conditions.