THE DECOMPOSITION OF MANGROVE LITTER IN A SUBTROPICAL MANGROVE FOREST

Decomposition of Avicennia marina (Forsk.) Vierh. leaf and woody litte r (twigs) was studied using litter bag experiments in a subtropical ma ngrove forest at two tidal levels (high and low) with different inunda tion regimes and during two seasons (summer and winter). Losses in dry weight were best described by a single exponential model which showed loss rates of both leaves and twigs were significantly higher low dow n on the shoreline (greater inundation) and in summer. The time (days) required for the loss of half of the initial dry weight (t(50)) was s ummer: high 59, low 44; winter: high 98, low 78. For twigs the values (days) were summer: high 383, low 179; winter: high 1327, low 1207. Th ere is an exponential relationship between leaf litter t(50)'s and lat itude which indicates the importance of temperature and therefore seas on, to the dynamics of organic cycling and export in mangrove systems.