Informatics Publishing Limited

Minshen Huang ¹, Qing Li ², Tongchao Le ³, Fanglin Tan ³

Affiliations
1 Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian 361005, CN
2 Center for Earth System Science, Ministry of Education Key Laboratory for Earth System Modeling, Tsinghua University, Beijing 100084, CN
3 Fujian Academy of Forestry, Fuzhou, Fujian 350012, CN

Abstract

Field species composition investigation showed an obvious zonation pattern of three main species of mangrove forests along Zhangjiang estuary. Aegiceras corniculata was mostly found in upstream and Avicennia marina mainly distributed in intermediate and downstream, while Kandelia obovata grows across the estuary and a majority in upstream and intermediate. Foliar carbon isotope discrimination of the three species, decreased from both upstream to downstream and wet to dry season, indicated their increased water use efficiency to increased soil salinity and decreased availability of freshwater. Increased ocean water uptake ratio (increased δ¹⁸O values) of all the three species from upstream to downstream further indicated their adaptations to decreased availability of freshwater. Decreased responses of water use efficiency in response to ocean water uptake ratio were also observed in all the three species. Significant relations observed in Avicennia marina and Kandelia obovata may indicate their higher adaptations to increased ocean water uptake than Aegiceras corniculata with no significant relationships, which may explain why the distribution of Aegiceras corniculata was confined to the low salinity area. All the results above, implicated that the zonation pattern of mangrove forests were linked to their physiological process on how water use efficiency responded to change of ocean water uptake ratio.

Keywords

Mangrove, Zonation Pattern, Water Use Efficiency, Water Sources, Stable Isotopes.

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