THE EFFECT OF INCREASED SEDIMENT ACCRETION ON THE SURVIVAL AND GROWTHOF RHIZOPHORA-APICULATA SEEDLINGS

The effects of experimental sediment accretion on the survival and gro wth of Rhizophora apiculata seedlings planted on an expanding mud flat in Pak Phanang Bay (south-east Thailand) were assessed. Seedling mort ality rates increased linearly (R-2=0.87, F=75.9, P<0.0001) with incre asing sediment accretion, at a rate of 3% per cm of sediment deposited , and implied a 96% increase in mortality at the highest sediment accr etion applied (32 cm). Similarly, seedling growth declined linearly wi th increasing sediment accretion (r=-0.95, P<.001) with the seedlings receiving 32 cm of sediment showing no significant growth. These resul ts clearly show that Rhizophora a apiculata seedlings will not be effi cient colonizers of coastal areas exposed to sudden events of high (>4 cm) sediment accretion and, therefore, afforestation programmes based on this species are unlikely to be successful in such areas. (C) 1997 Academic Press Limited.