Weizhi Lu, Luzhen Chen, Wenqing Wang, Nora Fung-Yee Tam, Guanghui Lin.Acta Oecologica,2013.49: 83-91.

Mangroves will either face longer tidal inundation or retreat landwards in response to on-going acceleratedsea level rise. However, little is known about the growth, regeneration or colonization ofmangrove seedlings under the different tidal inundation regimes associated with accelerated sea levelrise. In the present study, a field survey and a greenhouse mesocosm experiment were conducted toevaluate possible effects of accelerated sea level rise on colonization, establishment and seedling growthof a mangrove pioneer species, Avicennia marina. Avicennia populations at different elevations of theintertidal zone on Xiamen Island in Fujian Province, China showed distinctive patterns in both seedlingdensity and plant age. The seedlings at lower elevations had less annual biomass accumulation andpopulation productivity, but higher shoot to root ratios, suggesting that elevation has positive effects onseedling growth. The greenhouse mesocosm experiment with 1-year-old A. marina seedlings utilized fiveinundation periods (0, 2, 4, 6 and 12 h in a semidiurnal tidal cycle) and two inundation depths (rootimmersion and canopy immersion). Both inundation period and depth exerted significant and negativeeffects on biomass accumulation, photosynthetic rate, leaf electron transportation and water use efficiency.However, the negative effects of canopy immersion were more profound than root immersion.Canopy immersion exacerbated the effects of prolonged inundation, with no seedlings surviving undercanopy immersion at the 12-hour treatment. These results suggest that at lower elevations with highersea level, canopy immersion will have greater negative effects on seedling colonization, establishmentand early growth of A. marina. This finding is instrumental in predicting the future dynamics of mangroveforests under increasing sea levels.