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Rhizophora is the dominant genus of mangrove forests on the Atlantic coast of northern South America. What determines the zonation frequently observed in sympatric populations of the two neotropical species, R. mangle and R. racemosa, and their hybrids, R. × harrisonii, is an open question. The most widely held hypothesis is that differences in salinity tolerance among the taxonomic groups explain the observed zonation. To address this question, we analyzed the elemental composition of soils and canopy leaves from 60 Rhizophora spp. trees distributed in different intertidal zones of an estuarine site of the Paria Gulf, Venezuela. The low intertidal zone showed lower salinity, organic matter, C, N, S, and Na, and higher bulk density, Al, Fe, and Mn concentrations compared with the higher intertidal zones. Using morphological characters and microsatellite molecular markers, we identified 39 pure R. mangle, 19 …