Abstract :
An ecological study was carried out to determine nutrient levels of sediments, plant tissues and nutrient dynamics in anAegiceras corniculatum–Kandelia candeldominated forest in Futian Mangrove Nature Reserve, Shenzhen, the Peopleʹs Republic of China. The average tree height of the mangrove is 4•5 m with no vertical stratification. Allometric methodology was used to measure the biomass, and yield a figure of 108•26 t ha−1. The annual growth of the forest (1992) 15•92 t ha−1and the litterfall rate amounted to 11•49 t ha−1. Nutrient stocks of N, P and K in this mangrove were 616•05, 128•63 and 801•17 kg ha−1, with an annual accumulation of 91•34, 14•74 and 130•60 kg ha−1, and with an annual return of 88•30, 12•85 and 29•32 kg ha−1in the form of litter, respectively. The annual uptake (accumulation+return) for N, P and K was 179•64, 27•59 and 159•92 kg ha−1, respectively, in 1992. It seems that this mangrove community is close to equilibrium in terms of import and export of N and P, but has an obvious conservation of K. Enrichment ratios of N, P and K were at 1•10, 0•81 and 0•76, respectively, lower than their counterparts in terrestrial forests. The turnover rate (the stock amount in the community/annual return) of N, P and K was estimated at 7, 10 and 27 years, respectively. Flow coefficients and translocation rates, which reveal the dynamic processes of nutrients between mangrove plants and sediments, are also discussed.
