Dispersal property and early growth of mangrove propagules of Rhizophora apiculata and Avicennia marina.

Seed dispersal study is essential to understand the population dynamics, which is fundamentally important to support the conservation and management of mangrove ecosystem. A laboratory study was conducted to investigate the propagule dispersal properties of two important mangrove species in Malaysia, Avicennia marina and Rhizophora apiculata. Propagules of both species were collected from the wild and released into the salinity treatments of 0, 10, 20 and 30 ppt. The dispersal properties of the propagules were observed for 60 days. In the saltwater, A. marina propagules showed high viability rate, always buoyant and developed roots and shoots rapidly while R. apiculata propagules also presented high viability rate, but their buoyancy depended on salinity and they had slower growth rate. Both species developed poorly in the freshwater especially those of A. marina. Overall, the propagule dispersal properties were significantly different between species and between freshwater and saltwater. A. marina propagules possess greater attributes to be dispersed in open coast while R. apiculata propagules are more adapted to the inland areas. The dispersal potentials of both species were found corresponded to their natural distributions in the west coast of Peninsular Malaysia. This supports the notion that propagule dispersal is one of the determinants of species distribution and abundance. [ABSTRACT FROM AUTHOR]