The existence of monospecific zones is characteristic of mangroves of the river Mucuri, BA, where Laguncularia racemosa L. and Rhizophora mangle L. occupy regions under higher influence of the tide and Avicennia germinans L. is limited to places with lower salinity. The mangrove vegetation can be classified in riverine forests (margin of the river) and basin forests (interior). Physico-chemical parameters of the sediment and their relationship with the concentration of foliar nutrients were related to the distribution of the species. The results showed that A. germinans dominates sites with lower pH, salinity, charge for cationic exchange and silt values and higher clay content than the other two species. The substract of R. mangle was characterised by higher organic matter and fine sandy structure. Regarding the soil, the riverine and the basin forests presented sandy and loamy soils, respectively. Sediments of A. germinans showed the lowest macronutrient contents while R. mangle showed the highest ones, mainly in the cationic exchanges (K, Ca and Mg). Species restricted to the sites with high macronutrient contents showed lower foliar concentration of chemical elements. A. germinans accumulated higher macronutrient content while L. racemosa and specially R. mangle were higher in micronutrient. Despite of growing in richer substract in Mn, L. racemosa accumulated the smallest contents of this element in leaves. The low values of Fe and Zn concentration factor in R. mangle and of Mn in L. racemosa suggest that these species are more adapted to the occupation of sites with larger concentrations of those micronutrients.
Mangrove; minerals; zonation; Avicennia germinans; Laguncularia racemosa; Rhizophora mangle
