Reasons for reforestation success and failure with three mangrove species in Colombia

Abstract

As a result of human-induced changes in the hydrology of the lagoon system of the Ciénaga Grande de Santa Marta, Caribbean coast of Colombia, 60% of the originally 51 000 ha of mangrove forest have died. The main reasons for this mass mortality were hypersalinization, increased sedimentation rates, and lowering of the water level. During the 1989–1998 period, efforts were made to reestablish the destroyed areas. The rehabilitation measures started with monitoring and the reopening of obstructed channels to introduce more freshwater into the area. Between 1994 and 1997, the first reforestation experiments with propagules, seedlings, and saplings were carried out at two sites with reestablished hydrology. The experiments with Avicennia germinans, Laguncularia racemosa, and Rhizophora mangle showed that the reforestation success depends mainly on site selection and preparation. Generally, all species developed best at sites with low salinities and a water level near the soil surface. Highest mortalities were found in set propagules and seedlings of L. racemosa and A. germinans, whereas the best survival rates occurred in R. mangle propagules as well as in L. racemosa saplings. Growth rates, especially of L. racemosa, were extremely high when the ecological factors were favourable, and flowering set in early.