Introduction: In the last fifty years, the lagoon system of the Ciénaga Grande de Santa Marta (Fig. 1) was exposed to contrary interventions in its hydrological system. The gradual reduction of freshwater supply from 1960 to 1995 resulted in salinity increase and death of 286 km2 of mangrove forests. With the purpose to restore the ecosystem and to renew the freshwater supply, from 1995 to 1998 several channels between the Magdalena River and the lagoon system were reopened (Perdomo et al., 1998). It was expected that mangroves would regenerate quickly after the reduction of salinity. But in the western part of the lagoon system vegetation regenerated in an unexpected way. Our observations showed that in this part surface water salinity was of important influence on the species composition of the regenerating vegetation (Röderstein et al., in preparation). Here we present the results of our study carried out between km 15 and km 27 south of the Barranquilla-Ciénaga Road (Fig. 1, 2).
